" s1997 vau| sm 00| 0|eng d" (VPI) etd-3345131939761081 Walker, Gordon James Conceptual Development and Empirical Testing of an Outdoor Recreation Experience Model: The Recreation Experience Matrix (REM) Computer data - 5 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1997 Thesis (PHD)--Virginia Polytechnic Institute and State University, 1997-03-31 Includes bibliographical references. This dissertation examines four issues, including: (a) whether outdoor recreation experiences not included in the Recreation Experience Preference (REP) scales exist; (b) whether these experiences can be categorized using a framework called the Recreation Experience Matrix (REM); (c) how well the Recreation Opportunity Spectrum (ROS) variables of activity, setting, and expertise explain the types of experiences outdoor recreationists receive; and (d) how well two new variables--primary mode and mode dependence--explain the types of experiences outdoor recreationists receive. In order to address these issues, an on-site questionnaire was distributed at Mount Rogers National Recreation Area in Virginia during October and November, 1995. A total of 410 people completed this questionnaire. Of these, 336 provided useable addresses for a follow-up mail-out questionnaire, with 169 (50.3%) actually returning it. After performing a variety of statistical analyses, it was found that: (a) some outdoor recreationists did report having non-REP experiences involving identity, cognition, absorption, and self-concept; (b) indirect support does exist for classifying outdoor recreation experiences using the REM framework; and (c) the ROS variables of activity, setting, and expertise, do explain some outdoor recreation experiences, as do the new variables of primary mode and mode dependence. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. outdoor recreation recreation experience preference scales recreation experience matrix recreation opportunity spectrum Virginia Tech Forestry Daniel R. Williams Committee Member K. Jill Kiecolt Committee Member Bradley R. Hertel Committee Member Joseph W. Roggenbuck Committee Co-Chair R. Bruce Hull Committee Co-Chair unrestricted http://scholar.lib.vt.edu/theses/available/etd-3345131939761081/ " s1997 vau| sm 00| 0|eng d" (VPI) etd-171110282975860 A'Hearn, Francis W. The Industrial College of the Armed Forces: Contextual Analysis of an Evolving Mission, 1924-1994 Computer data - 10 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1997 Thesis (PHD)--Virginia Polytechnic Institute and State University, 1997-04-21 Includes bibliographical references. This study assessed the changing mission of the Industrial College of the Armed Forces as it evolved from the institution's founding as the Army Industrial College in 1924 to its 70th anniversary in 1994. The study drew heavily from archival materials in the Special Collections of the National Defense University in Washington, DC. The problem investigated in this research was to analyze how and why the institution's mission changed over time within the context of internal and external forces and events. Based upon the historical method of research, the study identified six periods in the institution's development over seven decades: its origins in the aftermath of World War I from 1918 to 1924; its growth in the interwar years, 1924 to 1940; the institution's temporary closure and subsequent reconstitution as the Industrial College of the Armed Forces during and after World War II, from 1940 to 1947; a formative period during the Cold War from 1947 to 1962; its continuing evolution throughout the Vietnam era from 1962 to 1974; and finally the College's modern development as a joint service educational institution from 1974 to 1994. The study found that the institution has changed dramatically over much of this century, just as the world and the country's national security concerns have changed profoundly in the same period. The mission of the College has evolved from a narrow focus on training military officers in procurement and industrial mobilization to that of a graduate institution dedicated to educating a select group of promising senior military and civilian officials in the political, economic, and resource dimensions of national security. Over time, the focus has shifted from training to education, from military to national issues, from internal and external educational programs to primarily internal ones, and from a predominant interest in domestic issues to an equally strong concern for international matters. The study finds that a variety of internal and external events and forces have impelled these changes. A wide range of influential individuals and stakeholders, bureaucratic power structures, governmental agencies, special review boards, and various political, economic, military, and social considerations have influenced the mission of the College. The study also concludes that several factors have likely contributed to the institution's relatively unusual longevity as a government entity. Its dual identity as an educational institution and a government organization set apart from the mainstream bureaucracy has had a favorable influence. So too has the institution been aided by the unique service it has provided to multiple customer constituencies. In fact, the College's mission has made it unique as an institution of adult education and learning in this country and perhaps the world. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. History Adult Education Armed Forces Virginia Tech Adult Education John Bokel Harold Stubblefield Committee Chair Marcie Boucouvalas Thomas Hunt Albert Wiswell unrestricted http://scholar.lib.vt.edu/theses/available/etd-171110282975860/ " s2000 vau| sm 00| 0|eng d" (VPI) etd-05012000-14030054 Bell, Tannisha D. An Examination of Race and Recurrent Substance Problems in the United States Computer data - 1 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 2000 Thesis (MS)--Virginia Polytechnic Institute and State University, 2000-04-17 Includes bibliographical references. Several studies show that African-Americans are less likely than whites to use alcohol or drugs. However, if African-Americans use drugs then they are more likely to become heavy and persistent users. African-Americans are also more likely to have a current substance abuse disorder. There is not much in the literature to explain this phenomenon. The purpose of this study is to examine the alcohol and drug abuse, use and dependence of blacks and whites in order to explain the differences in the course of the substance disorder, using data from the National Comorbidity Survey. There are many variables thought to contribute to the racial difference, such as socio-economic status (measured by income and education), religion, insurance, employment status, and marital status. The data in this literature indicate that the aforementioned variables do not explain the racial difference in substance disorders. However, after performing interaction analyses, it is clear that the effects of treatment are different for blacks and whites. Treatment is more effective for whites, and it may even cause the substance disorder to become worse for blacks. Several studies indicate that this may be the result of cultural differences between the treatment staff and the clients. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. African-Americans Drugs Substance Abuse Race Virginia Tech Sociology Clifton Bryant Committee Member Donald Shoemaker Committee Co-Chair Michael Hughes Committee Co-Chair restricted http://scholar.lib.vt.edu/theses/available/etd-05012000-14030054/ " s1997 vau| sm 00| 0|eng d" (VPI) etd-3621112139711101 Ahmad, Syed Alwi B. Fermion Quantum Field Theory In Black-hole Spacetimes Computer data - 1 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1997 Thesis (PHD)--Virginia Polytechnic Institute and State University, 1997-04-18 Includes bibliographical references. The need to construct a fermion quantum field theory in black-hole spacetimes is an acute one. The study of gravitational collapse necessitates the need of such. In this dissertation, we construct the theory of free fermions living on the static Schwarzschild black-hole and the rotating Kerr black-hole. The construction capitalises upon the fact that both black-holes are stationary axisymmetric solutions to Einstein's equation. A factorisability ansatz is developed whereby simple quantum modes can be found, for such stationary spacetimes with azimuthal symmetry. These modes are then employed for the purposes of a canonical quantisation of the corresponding fermionic theory. At the same time, we suggest that it may be impossible to extend a quantum field theory continuously across an event horizon. This split of a quantum field theory ensures the thermal character of the Hawking radiation. In our case, we compute and prove that the spectrum of neutrinos emitted from a black-hole via the Hawking process is indeed thermal. We also study fermion scattering amplitudes off the Schwarzschild black-hole. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. General Relativity Quantum Field Theory Virginia Tech Physics Lay Nam Chang Committee Chair M. Blecher T. Mizutani B.K. Dennison T. Takeuchi unrestricted http://scholar.lib.vt.edu/theses/available/etd-3621112139711101/ " s1997 vau| sm 00| 0|eng d" (VPI) etd-133422039701091 Anderson, Alaric Lee Investigation of Steel Joist Supported Wood Floor Systems Computer data - 6 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1997 Thesis (MS)--Virginia Polytechnic Institute and State University, 1997-02-01 Includes bibliographical references. This study investigates four aspects associated with steel joist supported wood floor systems: 1) acceptability, 2) prediction of deflection, 3) prediction of frequency, and 4) effects of diagonal bracing. Six full scale floor systems and two two-joist floor systems were constructed in the laboratory. Span length, joist spacing and diagonal bracing were the only parameters modified for each floor. Four tests were performed for each floor setup: heel drop impact, walking perpendicular and parallel to the floor joists, static concentrated load at midspan, and testing to determine subjective evaluation. Five acceptability criteria were investigated: Swedish Building Technology Design Guide, Australian Standard Domestic Metal Framing Code, Canadian Timber Floor Criterion, Murray's Criterion, and Johnson's Criterion. The results from these criteria were compared to the measured results of each floor system. Four methods to predict vertical deflection due to a static load at midspan were compared to measured values of each floor system. The effect of diagonal bracing on floor stiffness was also investigated. Results and concusions were made for each aspect investigated. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. none Virginia Tech Civil Engineering T. M. Murray Committee Chair R. H. Plaut None T. E. Cousins None unrestricted http://scholar.lib.vt.edu/theses/available/etd-133422039701091/ " s1997 vau| sm 00| 0|eng d" (VPI) etd-23281533974920 Ackley, John A. Weed Management Programs in Potato, Transplanted Tomato and Transplanted Pepper with Rimsulfuron and Other Herbicides Computer data - 1 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1997 Thesis (PHD)--Virginia Polytechnic Institute and State University, 1997-03-31 Includes bibliographical references. Weed management programs in ŒSuperior' potato with PRE and POST rimsulfuron treatments were investigated during 1992, 1993, and 1994. Common ragweed control by PRE combinations of metolachlor with linuron or metribuzin was higher when treatments included PRE or POST rimsulfuron. Common lambsquarters control was 93 to 96% by treatments that included POST rimsulfuron. Applications of 35 g ai/ha rimsulfuron plus 280 g ai/ha metribuzin POST controlled weeds comparable to sequential applications. Potato recovered from occasional injury caused by rimsulfuron, rimsulfuron plus metribuzin, and organophosphate insecticides combined POST with rimsulfuron plus metribuzin. Several acetolactate synthase (ALS)-inhibiting herbicides were evaluated for yellow nutsedge control in the greenhouse. Herbicides were applied POST to yellow nutsedge at actual or anticipated commercial rates. Yellow nutsedge control was 92 and 71% from halosulfuron and chlorimuron, respectively. Control ranged from 48 to 69% from primisulfuron, pyrithiobac, and rimsulfuron. Control from nicosulfuron and imazethapyr was 45 and 68%, respectively, while thifensulfuron and CGA-152005 had almost no activity on yellow nutsedge. Chlorimuron, imazethapyr, and halosulfuron were the only herbicides which reduced yellow nutsedge regrowth., Rrimsulfuron was evaluated in tomato at 26 and 35 g ai/ha, sequentially at 26 g/ha, at 26 g/ha plus metribuzin at 280 g ai/ha, and metribuzin at 280 g/ha were evaluated POST for weed control in transplanted ŒAgriset' tomato. Common lambsquarters was controlled by rimsulfuron at 35 g/ha. Rimsulfuron plus metribuzin gave consistent control of common ragweed but jimsonweed and goosegrass control was generally low. Rimsulfuron treatments caused < 12% injury to tomato. Tomato yield was consistently high in the metribuzin, metribuzin plus rimsulfuron, and rimsulfuron sequential treatments. In greenhouse studies, giant foxtail and large crabgrass control by rimsulfuron was above 95 and 85% respectively, but goosegrass was not controlled. Height of four tomato cultivars was not reduced, but dry weight of ŒFloradade' and ŒSunbeam' was reduced by rimsulfuron. In 1993, 1994 and 1995, PPI clomazone at 390 g ai/ha, POST rimsulfuron at 35 g ai/ha, and PPI trifluralin at 560 g ai/ha were evaluated for weed control in transplanted ŒKeystone RG3' bell pepper. Common lambsquarters and jimsonweed control was highest by clomazone treatments, while common ragweed control was low from all treatments. Keystone RG3 in the field and greenhouse and ŒCamelot', ŒJupiter' and ŒMemphis' in the greenhouse were injured by POST rimsulfuron and had lower height and dry weight than untreated controls. In the greenhouse, black nightshade control was below 23% and jimsonweed control was below 49% by rimsulfuron POST. The absorption, translocation, and metabolism of rimsulfuron was investigated in three Solanaceous weed species. Rimsulfuron uptake did not differ between black nightshade and eastern black nightshade while less labeled herbicide was absorbed by hairy nightshade. Black and eastern black nightshade translocated up to 50% of the labeled herbicide out of the treated leaf with 40 to 50% of the herbicide being moved to the actively growing regions of the plant. In hairy nightshade, an average 40% of the labeled herbicide was moved out of the treated leaf and less than 30% of the translocated herbicide was moved basipetally. Most major metabolites were apparent at 24 and 48 hours however, there were no differences in metabolite composition. Rimsulfuron will be an effective herbicide for use in weed management programs in potatoand tomato, however rimsulfuron causes too much injury in pepper to be used. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. clomazone metribuzin trifluralin pepper potato rimsulfuron nightshade tomato Virginia Tech Plant Pathology, Physiology, and Weed Science Henry P. Wilson Committee Chair E. Scott Hagood None John Hess None Kriton K. Hatzios None Ronald D. Morse None unrestricted http://scholar.lib.vt.edu/theses/available/etd-23281533974920/ " s1997 vau| sm 00| 0|eng d" (VPI) etd-123322282975860 Adams, Nicole An Ongoing Dialogue Computer data - 1 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1997 Thesis (MA)--Virginia Polytechnic Institute and State University, 1997-02-03 Includes bibliographical references. This thesis is an attempt to reconcile the form of an idea with the form of a thing in this world to be experienced. An exploration of the meaning behind the words idea, form, making and experience begins to unite the intellect of an architect with the design of an architect. The terms are defined in the thesis and explained through the project. The thesis through the project sets out to take these terms beyond mere words and give them an opportunity to inform eachother. It is this dialectic between idea, form, making and experience that I believe to be the heart of architecture. Idea and form are inextricably tied to one another. đWhich is the origin of the other?ø is not as pertinent a question as đhow do the two inform each other?ø. Ideas change from project to project as do the forms inherent in those ideas. Preceeding both idea and material form is another type of form that is immaterial and often remains unseen. It is the character which is essential to a thing. Whether it be a place or an object, it is the quality in the thing itself. This character is the instigator of idea and form. It is the architect£s goal to make this inherent form perceivable. An architect makes idea and form manifest through a concept of making. In Notes for a Theory of Making in a Time of Necessity, Giuseppe Zambonini emphasizes that đWe must look not only at the quality of the material used and at the craft employed, but also at the quality of the thought process selecting and shaping the material. . .quality cannot be an intrinsic condition that belongs to the object . . . but rather it must express the intent by which it is created and therein the clarity and strength of the meaning being produced by its formø (Zambonini, 21). This quality of design can best be achieved the earlier making and materiality are involved in the design process. The questions of đwhat is the form of this idea?ø and đhow is this form to be made?ø begin the relationship between idea, form and making. The immediate responses may be intuitive, but the final one is the resultof numerous makings. This is why architecture is practiced. When the question arises:đhow can this form not only embody an idea but be the idea?ø, the dialogue takes on a greater import. The way in which a thing will be experienced starts to inform its making. đIt is the process that will engage both user and observer in an active, participating relationship with the work and thereby give the work its meaningø (Zambonini, 21). It is at this point that the dialectic is fully engaged. These four aspects simultaneously inform each other and nurture the project throughout its life, from drawing board, to construction to the various experiences that it will impart. It is not just one aspect, but these four in communion that are the architecture. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. none Virginia Tech Architecture William Brown V. Hunter Pittman Frank Weiner unrestricted http://scholar.lib.vt.edu/theses/available/etd-123322282975860/ " s1997 vau| sm 00| 0|eng d" (VPI) etd-255314202974780 Al-Yakoob, Salem Mohammed Mixed-Integer Mathematical Programming Optimization Models and Algorithms For An Oil Tanker Routing and Scheduling Problem Computer data - 1 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1997 Thesis (PHD)--Virginia Polytechnic Institute and State University, 1997-02-27 Includes bibliographical references. This dissertation explores mathematical programming optimization models and algorithms for routing and scheduling ships in a maritime transportation system. Literature surveyed on seaborne transportation systems indicates that there is a scarcity of research on ship routing and scheduling problems. The complexity and the overwhelming size of a typical ship routing and scheduling problem are the primary reasons that have resulted in the scarcity of research in this area. The principal thrust of this research effort is focused at the Kuwait Petroleum Corporation (KPC) Problem. This problem is of great economic significance to the State of Kuwait, whose economy has been traditionally dominated to a large extent by the oil sector. Any enhancement in the existing ad-hoc scheduling procedure has the potential for significant savings. A mixed-integer programming model for the KPC problem is constructed in this dissertation. The resulting mathematical formulation is rather complex to solve due to (1) the overwhelming problem size for a typical demand contract scenario, (2) the integrality conditions, and (3) the structural diversity in the constraints. Accordingly, attempting to solve this formulation for a typical demand contract scenario without resorting to any aggregation or partitioning schemes is theoretically complex and computationally intractable. Motivated by the complexity of the above model, an aggregate model that retains the principal features of the KPC problem is formulated. This model is computationally far more tractable than the initial model, and consequently, it is utilized to construct a good quality heuristic solution for the KPC problem. The initial formulation is solved using CPLEX 4.0 mixed integer programming capabilities for a number of relatively small-sized test cases, and pertinent results and computational difficulties are reported. The aggregate formulation is solved using CPLEX 4.0 MIP in concert with specialized rolling horizon solution algorithms and related results are reported. The rolling horizon solution algorithms enabled us to handle practical sized problems that could not be handled by directly solving the aggregate problem. The performance of the rolling horizon algorithms may be enhanced by increasing the physical memory, and consequently, better solutions can be extracted. The potential saving and usefulness of this model in negotiation and planning purposes strongly justifies the acquisition of more computing power to tackle practical sized test problems. An ad-hoc scheduling procedure that is intended to simulate the current KPC scheduling practice is presented in this dissertation. It is shown that results obtained via the proposed rolling horizon algorithms are at least as good, and often substantially better than, results obtained via this ad-hoc procedure System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. ship scheduling aggregation mixed-integer programming Virginia Tech Mathematics H. Sherali Committee Chair T. Herdman None R. Wheeler None J. Burns None L. Johnson None restricted http://scholar.lib.vt.edu/theses/available/etd-255314202974780/ " s1997 vau| sm 00| 0|eng d" (VPI) etd-335713312971890 Appel, Justin Ronald Sensitivity Calculations For Conservation Laws With Application To Discontinuous Fluid Flows Computer data - 1 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1997 Thesis (PHD)--Virginia Polytechnic Institute and State University, 1997-03-14 Includes bibliographical references. Flow sensitivities are the derivatives of the variables that describe the fluid flow with respect to the parameters that determine the fluid flow. Sensitivities are of interest in their own right and are also of use in flow optimization, control and design and in the calculation of perturbed flows. Problems arise in all sensitivity calculation methods in the presence of discontinuities and other complexities such as shock waves, contact discontinuities and rarefaction waves that commonly occur in super and hypersonic inviscid, compressible fluid flows. Flow sensitivities are calculated using finite difference quotients, automatic differentiation and the sensitivity equation method for a variety of numerical methods. Explanations for the inaccuracies arising in the numerical approximations and implications these inaccuracies have on different applications are discussed. Possible corrections for the inaccuracies are outlined. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. none Virginia Tech Mathematics Max D. Gunzburger Committee Chair John A. Burns None Eugene M. Cliff None Terry L. Herdman None Janet S. Peterson None unrestricted http://scholar.lib.vt.edu/theses/available/etd-335713312971890/ " s1996 vau| sm 00| 0|eng d" (VPI) etd-104722369631841 Aliftiras, George Receiver Implementations for a CDMA Cellular System Computer data - 2 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1996 Thesis (MS)--Virginia Polytechnic Institute and State University, 1996-07-01 Includes bibliographical references. The communications industry is experiencing an explosion in the demand for personal communications services (PCS). Several digital technologies have been proposed to replace overburdened analog systems. One system that has gained increasing popularity in North America is a 1.25 MHz Code Division Multiple Access (CDMA) system (IS-95). In CDMA systems, multiple access interference limits the capacity of any system using conventional single user correlation or matched filter receivers. Previous research has shown that multiuser detection receivers that employ interference cancellation techniques can significantly improve the capacity of a CDMA system. This thesis studies two such structures: the successive interference cancellation scheme and the parallel interference cancellation scheme. These multiuser receivers are integrated into an IS-95 compatible receiver model which is simulated in software. This thesis develops simulation software that simulates IS-95 with conventional and multiuser receivers in multipath channels and when near-far conditions exist. Simulation results present the robustness of multiuser receivers to near-far in a practical system. In addition to multiuser implemenations, quantization effects from finite bit analog to digital converters (ADC) in CDMA systems will also be simulated. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. multiuser receiver CDMA interference cancellation quantization Virginia Tech Electrical and Computer Engineering Dr. Brian D. Woerner Committee Chair Dr. Theodore S. Rappaport Committee Member Dr. Charles W. Bostian Committee Member unrestricted http://scholar.lib.vt.edu/theses/available/etd-104722369631841/ " s1997 vau| sm 00| 0|eng d" (VPI) etd-831102339731121 Bethard, Greg L. A Microcomputer Simulation to Evaluate Management Strategies For Rearing Dairy Replacements. Computer data - 1 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1997 Thesis (PHD)--Virginia Polytechnic Institute and State University, 1997-04-18 Includes bibliographical references. A microcomputer simulation was developed as a tool for analyzing the dairy replacement enterprise. The simulation was constructed using a spreadsheet, and equations were developed using stepwise regression procedures. The simulation predicted BW, DMI, and fixed and variable costs for each week of a heifer£s life from birth to calving. After calving, milk yield, feed costs, and fixed costs were predicted for first lactation. Variation was estimated for each predicted variable, thus enabling normal distribution of predicted values. The simulation was used to analyze profitability of various growth rate scenarios and marginal costs associated with changing feed costs, heat detection efficiency, death loss, and abortion rate. For the growth rate analysis, six scenarios were evaluated: 1) normal growth from 5 wk to calving, 2) accelerated growth from 5 wk to calving, 3) slow growth from 5 wk to calving, 4) normal growth from 5 wk to 14 mo and accelerated growth from 14 mo to calving, 5) accelerated growth from 5 wk to 14 mo and control growth from 14 mo to calving, and 6) slow growth from 5 wk to 14 mo and accelerated growth from 14 mo to calving. Average daily gain from birth to calving was 0.78, 0.90, 0.62, 0.78, 0.75, and 0.80 kg/d, and age at calving was 25.1, 23.1, 27.4, 23.1, 23.0, and 23.1 mo, respectively. Total rearing cost from birth to calving was 1246, 1220, 1275, 1148, 1148, and 1138 $/heifer, and net profit through first lactation was 399, 407, 319, 441, 432, and 463 $/heifer, respectively. Results suggest modest growth rates from birth to calving (0.75 to 0.80 kg/d) with reduced first calving age (<24 mo) is most desirable, and delayed calving (>24 mo) is costly and merits higher growth rates with earlier breeding. Increasing feed costs, death loss at birth through weaning, or abortion rate one percentage point increased rearing costs 7.33, 2.40, and 9.10 $/heifer. Improving heat detection efficiency one percentage point reduced rearing costs $2.80/heifer. For the heat detection analysis, the relationship between age at first calving and total rearing costs was -584.38 + 73.49 x calving age in mo (R-squared = 0.97), for ages at first calving from 24.4 to 26.6 mo. Results of this research agree with field observations that managers should strive for early calving (<24 mo) and modest growth rates (0.75 to 0.80 kg/d) to maximize profitability of the replacement enterprise. In addition, death loss, abortion rate, and heat detection efficiency are variables that a manager must control to minimize heifer rearing costs. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. dairy simulation model heifer Virginia Tech Dairy Science Carl E. Polan Thomas L. Bailey Robert E. James Committee Chair Charles C. Stallings Michael L. McGilliard unrestricted http://scholar.lib.vt.edu/theses/available/etd-831102339731121/ " s1997 vau| sm 00| 0|eng d" (VPI) etd-454016449701231 Allan, James P. The British Labour Party in Opposition, 1979-1997: Structures, Agency, and Party Change Computer data - 10 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1997 Thesis (MA)--Virginia Polytechnic Institute and State University, 1997-04-24 Includes bibliographical references. The British Labour Party has spent eighteen years in opposition since 1979. During that time it lost four consecutive general elections to the Conservative Party. In 1997, however, it now looks set to win its first election since 1974. This thesis examines the Labour Party in opposition since 1979, using a theoretical framework informed by Anthony Giddens' structuration theory. Based on a dialectical notion of the structure and agency linkage, a two-tiered framework is constructed which at one level views a political party as consisting of a set of structures which can constrain and enable party leaders in their attempts to make the party electorally successful, and at another level the party is regarded as a collective agent in its own right, which in turn is subject to the effects of larger external structures. By comparing the strategies adopted by the Labour Party and its leaders since 1979, the thesis demonstrates that the apparent recovery in the Party's electoral fortunes has corresponded with an increase in the ability of agents to successfully negotiate structural constraints, whilst taking advantage of enabling structures. However, it is also clear that the transformation of Labour into an electorally viable party in 1997 is not solely the product of agency in the period since the last election; rather, it is the culmination of a longer-term process of party change. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. electoral performance The Labour Party structure and agency Virginia Tech Political Science Charles L. Taylor Committee Chair Stephen K. White Committee Member Rebecca H. Davis Committee Member unrestricted http://scholar.lib.vt.edu/theses/available/etd-454016449701231/ " s1997 vau| sm 00| 0|eng d" (VPI) etd-3034112939721181 Barake, Taha Mohamed A Generalized Analysis of Multiple-Clad Fibers with Arbitrary Step-Indx Profiles and Applications Computer data - 1 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1997 Thesis (MS)--Virginia Polytechnic Institute and State University, 1997-04-22 Includes bibliographical references. A generalized analysis of multiple-clad cylindrical dielectric structures with step-index profiles is presented. This analysis yields unified expressions for fields, dispersion equation and cutoff conditions for weakly guiding optical fibers with step-index but otherwise arbitrary profiles. The formulation focuses on triple-clad fibers, but can accommodate single and double-clad fibers as special limiting cases. Using the generalized solutions, transmission properties of several types of specialty fibers for broadband applications, including dispersion-shifted, dispersion-flattened, and dispersion compensating fibers, are studied. Improved designs for dispersion-shifted and dispersion compensating fibers are achieved. Fiber parameters and material compositions for the improved designs are provided. The proposed design for the dispersion-shifted fiber yields zero second-order as well as third-order dispersion at the 1.55 micrometer wavelength. The dispersion compensating fiber proposed here provides a large negative dispersion of about -400 ps/nm.km at the 1.55 micrometer wavelength for the fundamental mode. Numerical results for dispersion characteristics, cutoff wavelengths, and radial field distributions are provided. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. multiple-clad fibers dispersion-altered fibers Virginia Tech Electrical and Computer Engineering Dr. Lee Johnson Dr. Ioannis M. Besieres Dr. Ahmad Saffai-Jazi Committee Chair unrestricted http://scholar.lib.vt.edu/theses/available/etd-3034112939721181/ " s1996 vau| sm 00| 0|eng d" (VPI) etd-522014589642481 Almajdoub, Salahuddin A. A Design Methodology for Physical Design for Testability Computer data - 2 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1996 Thesis (PHD)--Virginia Polytechnic Institute and State University, 1996-07-01 Includes bibliographical references. Physical design for testability (PDFT) is a strategy to design circuits in a way to avoid or reduce realistic physical faults. The goal of this work is to define and establish a speci c methodology for PDFT. The proposed design methodology includes techniques to reduce potential bridging faults in complementary metal-oxide-semiconductor (CMOS) circuits. To compare faults, the design process utilizes a new parameter called the fault index. The fault index for a particular fault is the probability of occurrence of the fault divided by the testability of the fault. Faults with the highest fault indices are considered the worst faults and are targeted by the PDFT design process to eliminate them or reduce their probability of occurrence. An implementation of the PDFT design process is constructed using several new tools in addition to other "off-the-shelf" tools. The first tool developed in this work is a testability measure tool for bridging faults. Two other tools are developed to eliminate or reduce the probability of occurrence of bridging faults with high fault indices. The row enhancer targets faults inside the logic elements of the circuit, while the channel enhancer targets faults inside the routing part of the circuit. To demonstrate the capabilities and test the eff ectiveness of the PDFT design process, this work conducts an experiment which includes designing three CMOS circuits from the ISCAS 1985 benchmark circuits. Several layouts are generated for every circuit. Every layout, except the rst one, utilizes information from the previous layout to minimize the probability of occurrence for faults with high fault indices. Experimental results show that the PDFT design process successfully achieves two goals of PDFT, providing layouts with fewer faults and minimizing the probability of occurrence of hard-to-test faults. Improvement in the total fault index was about 40 percent in some cases, while improvement in total critical area was about 30 percent in some cases. However, virtually all the improvements came from using the row enhancer; the channel enhancer provided only marginal improvements. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. Bridging Faults The Labour Party Structure and Agency IDDQ Testing Electoral Performance Physical Design for Testability Virginia Tech Electrical and Computer Engineering Charles L. Taylor Committee Chair Rebecca H. Davis Committee Member Stephen K. White Committee Member Scott F. Midkiff Committee Chair James R. Armstrong Committee Member Hanif D. Sherali Committee Member Aicha A. Elshabini-Riad Committee Member Joseph G. Tront Committee Member unrestricted http://scholar.lib.vt.edu/theses/available/etd-522014589642481/ " s1996 vau| sm 00| 0|eng d" (VPI) etd-274210359611541 Atalla, Mauro J. Model Updating Using Neural Networks Computer data - 1 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1996 Thesis (PHD)--Virginia Polytechnic Institute and State University, 1996-04-01 Includes bibliographical references. Accurate models are necessary in critical applications. Key parameters in dynamic systems often change during their life cycle due to repair and replacement of parts or en- vironmental changes. This dissertation presents a new approach to update system models, accounting for these changes. The approach uses frequency domain data and a neural net- work to produce estimates of the parameters being updated, yielding a model representative of the measured data. Current iterative methods developed to solve the model updating problem rely on min- imization techniques to nd the set of model parameters that yield the best match between experimental and analytical responses. Since the minimization procedure requires a fair amount of computation time, it makes the existing techniques infeasible for use as part of an adaptive control scheme correcting the model parameters as the system changes. They also require either mode shape expansion or model reduction before they can be applied, introducing errors in the procedure. Furthermore, none of the existing techniques has been applied to nonlinear systems. The neural network estimates the parameters being updated quickly and accurately without the need to measure all degrees of freedom of the system. This avoids the use of mode shape expansion or model reduction techniques, and allows for its implementation as part of an adaptive control scheme. The proposed technique is also capable of updating weakly nonlinear systems. Numerical simulations and experimental results show that the proposed method has good accuracy and generalization properties, and it is therefore, a suitable alternative for the solution of the model updating problem of this class of systems. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. adaptive control neural networks model updating Virginia Tech Engineering Science and Mechanics Daniel J. Inman Committee Chair Harry H. Robertshaw Ali H. Nayfeh Ronald D. Kriz O. H. Griffin, Jr. unrestricted http://scholar.lib.vt.edu/theses/available/etd-274210359611541/ " s1997 vau| sm 00| 0|eng d" (VPI) etd-3210192049721391 Bail, Thomas R. A Disturbance-Rejection Problem for a 2-D Airfoil Exhibiting Flutter Computer data - 1 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1997 Thesis (MS)--Virginia Polytechnic Institute and State University, 1997-04-21 Includes bibliographical references. Flutter suppression is a problem of considerable interest in modern avionics. Flutter is a vibration caused by energy in the airstream being absorbed by a non-rigid wing. Active control is one possible method of suppressing flutter. However, due to unmeasurable aerodynamic-lag states, developing an active control using full-state feedback is not viable. The use of a state-estimator is a more practical way of developing active controllers. In this paper we investigate two control methods using state-estimators. We also use simple models of disturbances to test attenuation and robustness of each control method. Finally, a method of quantitative robust analysis is reviewed and then applied to each of the controlled systems. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. LQG H flutter singular values Virginia Tech Mathematics Dr. Terry Herdman Dr. Robert Rogers Dr. John Burns Committee Chair unrestricted http://scholar.lib.vt.edu/theses/available/etd-3210192049721391/ " s1996 vau| sm 00| 0|eng d" (VPI) etd-0521318109613220 Fleming, Todd B. Improving the Performance of the world Wide Web over Wireless Networks Computer data - 1 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1996 Thesis (MS)--Virginia Polytechnic Institute and State University, 1996-11-04 Includes bibliographical references. The World Wide Web (WWW) has become the largest source of Internet traffic, but it was not designed for wireless networks. Documents with large inline images take a long time to fetch over low-bandwidth wireless networks. Radio signal dropouts cause file transfers to abort; users have to restart file transfers from the beginning. Dropouts also prevent access to documents that have not yet been visited by the user. All of these problems create user frustration and limit the utility of the WWW and wireless networks. In this work, a new Wireless World Wide Web (WWWW) proxy server and protocol were developed that address these problems. A client based on NCSA Mosaic connects to the proxy server using the new protocol, Multiple Hypertext Stream Protocol (MHSP). The proxy prefetches documents to the client, including inline images. The proxy also reduces the resolution of large bitmaps to improve performance over slow links. MHSP provides the ability to resume file transfers when the link has been broken then reestablished. The WWWW system was tested and evaluated by running script-controlled clients on different emulated network environments. This new system decreased document load time an average of 32 to 37 percent, depending on network configuration. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. wireless networks WWW MHSP proxy threads protocols Virginia Tech Electrical and Computer Engineering Scott F. Midkiff Committee Chair Nathaniel J. Davis F. Gail Gray unrestricted http://scholar.lib.vt.edu/theses/available/etd-0521318109613220/ " s1996 vau| sm 00| 0|eng d" (VPI) etd-310141259631631 Batongbacal, Alan L. A User-Extensible Architecture for Visualization and Analysis of Time-Series Trace Data Computer data - 1 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1996 Thesis (MS)--Virginia Polytechnic Institute and State University, 1996-04-01 Includes bibliographical references. This thesis describes the design and implementation of Chitra95, a software system developed for the visualization and analysis of time-series trace data. Chitra95 is based upon two earlier generations of Chitra and is aimed at producing a system with broad applicability and utility in this area of research. This thesis contributes to the area of software design for trace visualization and analysis by proposing a set of design principles towards achieving the goals of system extensibility, reusability, reliability, testability and verifiability. These design principles are demonstrated by Chitra95, a software architecture proposed in this thesis for visualization and analysis of time-series trace data. This architecture is novel in its combination of independence from problem domain semantics; optimization for user-extensibility and code reusability; freedom from any specific user interface model; ability to simultaneously produce an integrated application and a reusable toolkit of parts that may either be customized into a turnkey system or integrated into other software systems; support for enhanced reliability, testability and verifiability; and support for an interface to the World Wide Web and for remote execution. Finally, this thesis makes the specific contribution of a data structure for representing large traces that permits the maintainance of multiple versions of a trace and retains the ability to undo modifications made to a trace. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. none Virginia Tech Computer Science Prof. Marc Abrams Committee Chair Prof. Dennis Kafura None Prof. Sallie Henry None unrestricted http://scholar.lib.vt.edu/theses/available/etd-310141259631631/ " s1996 vau| sm 00| 0|eng d" (VPI) etd-12164379662151 Battermann, Astrid Preconditioning of Karush--Kuhn--Tucker Systems arising in Optimal Control Problems Computer data - 1 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1996 Thesis (MS)--Virginia Polytechnic Institute and State University, 1996-06-14 Includes bibliographical references. This work is concerned with the construction of preconditioners for indefinite linear systems. The systems under investigation arise in the numerical solution of quadratic programming problems, for example in the form of Karush--Kuhn--Tucker (KKT) optimality conditions or in interior--point methods. Therefore, the system matrix is referred to as a KKT matrix. It is not the purpose of this thesis to investigate systems arising from general quadratic programming problems, but to study systems arising in linear quadratic control problems governed by partial differential equations. The KKT matrix is symmetric, nonsingular, and indefinite. For the solution of the linear systems generalizations of the conjugate gradient method, MINRES and SYMMLQ, are used. The performance of these iterative solution methods depends on the eigenvalue distribution of the matrix and of the cost of the multiplication of the system matrix with a vector. To increase the performance of these methods, one tries to transform the system to favorably change its eigenvalue distribution. This is called preconditioning and the nonsingular transformation matrices are called preconditioners. Since the overall performance of the iterative methods also depends on the cost of matrix--vector multiplications, the preconditioner has to be constructed so that it can be applied efficiently. The preconditioners designed in this thesis are positive definite and they maintain the symmetry of the system. For the construction of the preconditioners we strongly exploit the structure of the underlying system. The preconditioners are composed of preconditioners for the submatrices in the KKT system. Therefore, known efficient preconditioners can be readily adapted to this context. The derivation of the preconditioners is motivated by the properties of the KKT matrices arising in optimal control problems. An analysis of the preconditioners is given and various cases which are important for interior point methods are treated separately. The preconditioners are tested on a typical problem, a Neumann boundary control for an elliptic equation. In many important situations the preconditioners substantially reduce the number of iterations needed by the solvers. In some cases, it can even be shown that the number of iterations for the preconditioned system is independent of the refinement of the discretization of the partial differential equation. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. preconditioning optimal control quadratic programming karush-kuhn-tucker systems indefinite systems Virginia Tech Mathematics John A. Burns Christopher Beattie Matthias Heinkenschloss Committee Chair unrestricted http://scholar.lib.vt.edu/theses/available/etd-12164379662151/ " s1997 vau| sm 00| 0|eng d" (VPI) etd-4437152139711101 Zabaronick, Noel A. EYE TRACKING USING FIBER OPTICS AND COMPUTER VISION TECHNIQUES Computer data - 2 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1997 Thesis (MS)--Virginia Polytechnic Institute and State University, 1997-04-04 Includes bibliographical references. We describe a system for tracking the motion and determining the velocity of the human eye using a combination of fiber optics and imaging optics integrated with a CCD camera, a framegrabber, and a PC. Systems such as the one we describe are needed for monitoring location of interest for better human- computer interfaces and virtual reality simulations, for monitoring pilot cognitive skills during flight simulations, and for detecting the early warning signs of driver drowsiness. Where some eye-tracking devices are cumbersome because they require a person to limit head motion to remain in view of a camera or uncomfortable because they require the use of an elaborate headpiece, our proposed system is as simple to wear as a pair of eyeglasses, with the only added weight to the glasses being that of a fiber optic bundle. This fiber bundle guides the image of an 880 nm LED illuminated eye as it is reflected from a hot mirror built into the eyeglass assembly. The guided image is focused onto a CCD and the camera's output is linked to a PC framegrabber card. Software written in Microsoft Visual C++ locates the user's pupil in each video image and tracks the motion and velocity of the pupil over time. The prototype system tracks the center of the pupil to an accuracy of only 1/5 of the pupil size. This diminished accuracy results from the minimized computation scheme of pupil detection. The technique relies on edge detection and direction of image gradient over very few pixels so that the system is optimized for speed. Many other methods of pupil detection could be investigated in future research in order to optimize such a system for other parameters. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. none Virginia Tech Electrical and Computer Engineering Dr. Anbo Wang Committee Member Dr. Marten DeVries Committee Member Dr. Lynn Abbott Committee Member Dr. Richard O. Claus Committee Chair unrestricted http://scholar.lib.vt.edu/theses/available/etd-4437152139711101/ " s1997 vau| sm 00| 0|eng d" (VPI) etd-1123161739741061 Benning, Jennifer Lyn Development of Alternative Crab Claw Processing Systems to Minimize Environmental Impact Computer data - 3 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1997 Thesis (MS)--Virginia Polytechnic Institute and State University, 1997-03-14 Includes bibliographical references. Development of Alternative Crab Claw Processing Systems to Minimize Environmental Impact by Jennifer Lyn Benning Chair: Dr. Gregory Boardman Environemental Engineering (ABSTRACT) In the recent years, environmental regulations enforced by federal, state, and local agencies have increasingly addressed water quality issues through progressively more stringent regulations. These regulations have raised concerns in the blue crab industry because processors are now subject to regulations under which new processors are unable to meet the effluent limitations with current processing techniques. This study focuses on the mechanized processing of crab claws. Currently, processors use a brine bath, referred to as the Harris Claw machine, to separate crab claw meat and shell, and this process yields a wastewater which is significantly high in pollutant strength, and is untreatable by biological methods due to the toxicity associated with the high chloride concentrations found in the waste stream. Several alternative crab claw processing systems were developed and evaluated in terms of the meat product yield, the meat product quality, and the wastewater characterization. Two alternatives involved the use of dense media, a 22.5% Staley 1300 corn syrup solution with 5.0% salt and a 30.0% Staley 1300 corn syrup solution, to separate the crab claw meat and shell. These methods, in full scale tests, produced meat yields comparable to that of the brine solution and improved the overall taste of the meat product. However, the effluents had significantly higher BOD5 concentrations. Another alternative to the Harris Claw machine, involved the design, characterization, and testing of a hydraulic separator system (HSS). The HSS was tested on a small scale, but was found to have a meat yield comparable to the Harris Claw machine. The HSS significantly improved the flavor of a final meat product, although the HSS meat product had a significantly lower shelf life than the Harris Claw machine meat product. The wastewater quality was improved, because the HSS eliminates the problems associated with a high chloride ion concentration and potentially reduces overall water consumption. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. waste minimization enviromental impact crab claw blue crab processing Virginia Tech Environmental Engineering Dr. Gregory D. Boardman Committee Chair Dr. John C. Little Dr. George J. Flick unrestricted http://scholar.lib.vt.edu/theses/available/etd-1123161739741061/ " s1997 vau| sm 00| 0|eng d" (VPI) etd-5852152749721461 Berkelman, James Habitat Requirements and Foraging Ecology of the Madagascar Fish-Eagle Computer data - 1 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1997 Thesis (PHD)--Virginia Polytechnic Institute and State University, 1997-05-06 Includes bibliographical references. With a population estimate of 99 pairs, the Madagascar fish-eagle (Haliaeetus vociferoides) is one of the rarest birds of prey in the world. I investigated the ecological requirements of the Madagascar fish-eagle in 1994 and 1995 to help determine management action to prevent its extinction. I investigated fish-eagle foraging ecology in 1996 to determine its prey preference and whether fish abundance and availability affect fish-eagle foraging rates and foraging success. Madagascar fish-eagle nest and perch trees were taller, broader, had more unobstructed branches, and had a greater arc of accessibility than unused trees. Perch trees also were deciduous more often and had a narrower growth form than unused trees. Nest sites had more shoreline perch trees than unused sites. Lakes occupied by fish-eagles were deeper and clearer, and had more shoreline perch trees, more fish, a greater total fish weight, and more fish species than unoccupied lakes. I developed logistic regression models to predict the probability of Madagascar fish-eagle use based on the measured habitat variables. Nest and perch tree models included tree height. The nest site model included number of shoreline perches. Lake models included number of shoreline perches and either number of fish, total fish weight, or number of fish species. These models can be used to predict fish-eagle habitat use with > 70% accuracy. Introduced tilapia, Oreochromis spp. and Tilapia spp., made up the majority of both the gill net (66.3%) and fish-eagle catch (64.7%) in similar proportion, which suggests that the fish-eagle is an opportunistic predator. Replacement of native fish species by exotics, thus, probably has not been detrimental to the island's fish-eagle population. Male fish-eagle foraging success was positively correlated with number of fish, total fish weight, and number of fish species, which suggests that declines in the fish population could adversely affect the fish-eagle population. The results of this study indicate that Madagascar fish-eagles require bodies of water with large shoreline trees and an ample fish population. I recommend greater protection of aquatic habitats, monitoring and management of freshwater fish populations, and education of local people in sustainable tree harvesting practices. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. lake foraging nest tree madagascar fish-eagle perch tree habitat Virginia Tech Fisheries and Wildlife Sciences Brian R. Murphy department head Dean F. Stauffer John J. Ney Carola A. Haas James D. Fraser Committee Chair Richard G. Oderwald restricted http://scholar.lib.vt.edu/theses/available/etd-5852152749721461/ " s1998 vau| sm 00| 0|eng d" (VPI) etd-173510281975580 Zhang, Michael Tao Electrical, Thermal, and EMI Designs of High-Density, Low-Profile Power Supplies Computer data - 10 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1998 Thesis (PHD)--Virginia Polytechnic Institute and State University, 1998-02-17 Includes bibliographical references. This work presents the analyses and designs of high-density, low-profile power supplies, including the electrical, thermal, and EMI aspects. Emphasis is placed on forward and flyback converters. The efficiency improvements of employing synchronous rectification are theoretically derived and experimentally verified in forward and flyback converters. The performances of synchronous rectifiers in forward converters are analyzed with regards to transformer reset and SR driven method. The effectiveness of synchronous rectification in flyback converters is evaluated in various operation modes and control schemes. The paralleling techniques utilized to realize high-density, low-profile power conversion are presented. Current sharing in transformer paralleling is addressed and evaluated in forward topology. The performance and the operation principles of one-choke and two-choke interleaved forward converters are analyzed. The thermal management of high-density power supplies in sealed enclosures is optimized using computational fluid dynamics simulations. The theoretical limit of power density due to thermal constraint is determined. In addition, the thermal-design optimization guidelines are given and verified experimentally. A systematic methodology is developed to facilitate the analysis and design of conducted EMI problems in high-density power supplies. Partial element equivalent circuit method is employed for parasitic parameter extraction. Layout and packaging are optimized to minimize conducted EMI noises. Noise predictions by Saber simulations are confirmed by experimental measurements. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. none Virginia Tech Electrical and Computer Engineering Douglas J. Nelson Dan Y. Chen Lay N. Chang Dusan Borojevic Milan M. Jovanovic Committee Co-Chair Fred C. Lee Committee Co-Chair unrestricted http://scholar.lib.vt.edu/theses/available/etd-173510281975580/ " s1997 vau| sm 00| 0|eng d" (VPI) etd-317182749721461 Fischer, Patrick Numerical Simulation of Microwave Sintering of Zinc Oxide Computer data - 1 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1997 Thesis (MS)--Virginia Polytechnic Institute and State University, 1997-05-08 Includes bibliographical references. Experiments at the University of Maryland Plasma Physics Laboratory have discovered an unusual temperature response in the form of a "thermal wave" which begins at the center and propagates towards the surface of a zinc oxide sample, when heated in a microwave cavity without the presence of oxygen. This effect is believed to be caused by the irregular temperature dependence of the dielectric properties of zinc oxide, particularly dielectric loss. Two thermocouple probes were used to measure the temperature response in a small cylindrical sample of zinc oxide packed in powder insulation, and heated in a microwave oven. In order to determine if the unusual response is caused by the dielectric properties, this work uses a finite-difference mathematical model to simulate the experiments, both for the case of zinc oxide heated in ordinary air, as well as for the case of zinc oxide heated in nitrogen. A revised version of the model is used to determine if the thermocouple probe has any effect on the temperature of the sample. The spatial and temporal temperature distribution results from the model indicate that the thermocouple probe has a negligible effect on the results and that the "thermal wave" can be attributed to the irregular temperature dependence of the dielectric loss of the material. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. zinc oxide microwave heat transfer permittivity thermal wave Virginia Tech Mechanical Engineering Dr. J.R. Thomas Committee Chair Dr. E. P. Scott Dr. T. E. Diller unrestricted http://scholar.lib.vt.edu/theses/available/etd-317182749721461/ " s1996 vau| sm 00| 0|eng d" (VPI) etd-5741181879602301 Bhogaraju, Prabhakar V. V. A Case-Based Reasoner for Evaluating Crop Rotations in Whole-Farm Planning Computer data - 1 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1996 Thesis (MS)--Virginia Polytechnic Institute and State University, 1996-07-31 Includes bibliographical references. I have worked on a Case-Based Reasoning (CBR) system that evaluates crop rotations for their soil erosion and risk of insect pest problems. The purpose of this system is to provide decision support for an automated whole-farm planner (CROPS). CROPS (Buick et al., 1992) generates crop rotation plans that can address some of the environmental, economic and legislative pressures facing natural resource managers. To generate and recommend a crop rotation plan CROPS requires estimates on the soil erosion risks and pesticide pollution potential of the crop rotation. In this research I have designed and prototyped a system that can assist CROPS in the process of whole-farm planning by providing information required for determining the soil erosion risks and the pesticide pollution potential of crop rotations. Inputs for the system include: a crop rotation, its tillage and residue management practices, and field conditions. Soil erosion risk is quantified using the C-value. Pest risks are likelihood of pest outbreaks that require control in a crop rotation. CBR was the chosen methodology for system implementation. In CBR, solutions to new problem situations are derived from retrieving and adapting solutions to similar problem situations experienced in the past. The system was prototyped using Esteem, a CBR development shell, and runs on a PC under the MS. Windows operating system. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. none Virginia Tech Entomology Forrest W. Ravlin David H. Vaughan Nicholas D. Stone Committee Chair unrestricted http://scholar.lib.vt.edu/theses/available/etd-5741181879602301/ " s1997 vau| sm 00| 0|eng d" (VPI) etd-38419290973280 Bittner, Ray A. Jr. Wormhole Run-Time Reconfiguration: Conceptualization and VLSI Design of a High Performance Computing System Computer data - 1 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1997 Thesis (PHD)--Virginia Polytechnic Institute and State University, 1997-01-23 Includes bibliographical references. In the past, various approaches to the high performance numerical computing problem have been explored. Recently, researchers have begun to explore the possibilities of using Field Programmable Gate Arrays (FPGAs) to solve numerically intensive problems. FPGAs offer the possibility of customization to any given application, while not sacrificing applicability to a wide problem domain. Further, the implementation of data flow graphs directly in silicon makes FPGAs very attractive for these types of problems. Unfortunately, current FPGAs suffer from a number of inadequacies with respect to the task. They have lower transistor densities than ASIC solutions, and hence less potential computational power per unit area. Routing overhead generally makes an FPGA solution slower than an ASIC design. Bit-oriented computational units make them unnecessarily inefficient for implementing tasks that are generally word-oriented. And finally, in large volumes, FPGAs tend to be more expensive per unit due to their lower transistor density. To combat these problems, researchers are now exploiting the unique advantage that FPGAs exhibit over ASICs: reconfigurability. By customizing the FPGA to the task at hand, as the application executes, it is hoped that the cost-performance product of an FPGA system can be shown to be a better solution than a system implemented by a collection of custom ASICs. Such a system is called a Configurable Computing Machine (CCM). Many aspects of the design of the FPGAs available today hinder the exploration of this field. This thesis addresses many of these problems and presents the embodiment of those solutions in the Colt CCM. By offering word grain reconfiguration and the ability to partially reconfigure at computational element resolution, the Colt can offer higher effective utilization over traditional FPGAs. Further, the majority of the pins of the Colt can be used for both normal I/O and for chip reconfiguration. This provides higher reconfiguration bandwidth contrasted with the low percentage of pins used for reconfiguration of FPGAs. Finally, Colt uses a distributed reconfiguration mechanism called Wormhole Run-Time Reconfiguration (RTR) that allows multiple data ports to simultaneously program different sections of the chip independently. Used as the primary example of Wormhole RTR in the patent application, Colt is the first system to employ this computing paradigm. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. VLSI data flow DSP wormhole run-time reconfiguration FPGA Virginia Tech Electrical and Computer Engineering Scott F. Midkiff Nathaniel J. Davis A. Lynn Abbott Peter M. Athanas Committee Chair Calvin J. Ribbens unrestricted http://scholar.lib.vt.edu/theses/available/etd-38419290973280/ " s1997 vau| sm 00| 0|eng d" (VPI) etd-353622132974710 Zhong, Caoyuan Modeling of Airport Operations Using an Object-Oriented Approach Computer data - 3 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1997 Thesis (PHD)--Virginia Polytechnic Institute and State University, 1997-02-04 Includes bibliographical references. This research develops an object-oriented approach to model airport ground network traffic operations. A generic modeling library is developed as a tool kit to model the basic traffic operations in the airfield using an object-oriented approach. The proposed generic modeling library for airfield operations is a collection of predefined abstract components implemented in the Java object-oriented programming language. Classes are defined and used as the basic components in a variety of airfield operation modeling, simulations, and optimizations. The generic airport modeling framework consists of a set the components that are necessary for modeling the basic activities of airfield traffic operations. By using the multi-threading techniques, components are integrated into the proposed modeling framework. Unlike traditional sequential simulation model, this framework organizes simulation activities into four major groups which are: flight schedule, aircraft movement, time, and animation. Instead of using built-in control logic, the framework adapts an open system policy which gives the flexibility to the end users to incorporate the user-preferred control logic into the end models. Another purpose in this research is to provide a future mechanism to study airfield ground traffic automated control systems with Just-In-Time forecasting and model system performance in a real-time ATC environment. The proposed generic library could be implemented into a Internet/intranet ready application which can query real time information and provide real time advice to pilots and air traffic controllers. This study is one of a few current research projects that are of using multiple threading technique to study traffic operation problems. The proposed generic library is originally implemented with C++ and, in the final stage, with Java, a truly cross-platform object-oriented language. Application written in Java can run on most of the mainstream computer operating systems without modifications. Although the proposed library is for airfield traffic control system, it could also be extended into air traffic control system as well as advanced transportation system. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. airport simulation object-oriented modeling java Virginia Tech Civil Engineering Dr. Keying Ye Dr. R. Sivanandan Dr. Richard D. Walker Dr. Donald R. Drew Dr. Antonio A. Trani Committee Chair unrestricted http://scholar.lib.vt.edu/theses/available/etd-353622132974710/ " s1997 vau| sm 00| 0|eng d" (VPI) etd-145110201974500 Blanks, Joseph E. Optimal Design of an Enclosure for a Portable Generator Computer data - 1 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1997 Thesis (MS)--Virginia Polytechnic Institute and State University, 1997-02-07 Includes bibliographical references. A simple, effective design for enclosing portable generators to reduce the radiated noise is an idea that seems to be desired by the consumers in this market. This investigation is to determine the feasibility of producing such an enclosure for a generator. Several engineering aspects are incorporated in the design of the enclosure. The first, and probably the most paramount, are the acoustical effects of the enclosure itself. The investigation follows the theories for insertion loss of a close fitting enclosure. The thesis examines the system behavior of a close fitting enclosure that most acoustic text books ignore and how the material stiffness, density and source-to-enclosure distance affect the insertion loss and effectiveness of the enclosure. Measured and theoretical sound pressure level around the generator before and after the application of the enclosure are presented using standards described by ISO standard 1344. The second important consideration for the enclosure design involves the heat transfer characteristics. The requirements of cooling air to the generator are discussed. Also presented are some acoustic design considerations to prevent any "direct line of sight" to any of the necessary openings which will help in the overall insertion loss. The use of an optimal engineering design technique is presented, demonstrating its strengths and weakness in this application. The optimization method used for the study is the Hooke and Jeeves, or pattern search method. This method solved for the optimum material properties in approximately 30 iterations depending on the initial starting points and the desired weighting parameters. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. acoustic isolation insertion loss passive acoustical treatment close fitting enclosure optimization acoustic enclosure Virginia Tech Mechanical Engineering William R. Saunders Committee Chair Douglas J. Nelson Harry H. Robertshaw unrestricted http://scholar.lib.vt.edu/theses/available/etd-145110201974500/ " s1997 vau| sm 00| 0|eng d" (VPI) etd-1111112749721461 Bolling, John Glenn Implementation of Constrained Control Allocation Techniques Using an Aerodynamic Model of an F-15 Aircraft Computer data - 1 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1997 Thesis (MS)--Virginia Polytechnic Institute and State University, 1997-05-21 Includes bibliographical references. Control Allocation as it pertains to aerospace vehicles, describes the way in which control surfaces on the outside of an aircraft are deflected when the pilot moves the control stick inside the cockpit. Previously, control allocation was performed by a series of cables and push rods, which connected the 3 classical control surfaces (ailerons, elevators, and rudder), to the 3 cockpit controls (longitudinal stick, lateral stick, and rudder pedals). In modern tactical aircraft however, it is not uncommon to find as many as 10 or more control surfaces which, instead of being moved by mechanical linkages, are connected together by complex electrical and/or hydraulic circuits. Because of the large number of effectors, there can no longer be a one-to-one correspondence between surface deflections on the outside of the cockpit to pilot controls on the inside. In addition, these exterior control surfaces have limits which restrict the distance that they can move as well as the speed at at which they can move. The purpose of Constrained Control Allocation is to deflect the numerous control surfaces in response to pilot commands in the most efficient combinations, while keeping in mind that they can only move so far and so fast. The implementation issues of Constrained Control Allocation techniques are discussed, and an aerodynamic model of a highly modified F-15 aircraft is used to demonstrate the various aspects of Constrained Control Allocation. This work was conducted under NASA research grant NAG-1-1449 supervised by John Foster of the NASA Langley Research Center System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. flight control control allocation F-15 Virginia Tech Aerospace and Ocean Engineering Dr. Frederick Lutze Dr. Mark Anderson Dr. Wayne Durham Committee Chair unrestricted http://scholar.lib.vt.edu/theses/available/etd-1111112749721461/ " s1996 vau| sm 00| 0|eng d" (VPI) etd-17616979652211 Feldman, Michael A. Efficient Low-Speed Flight in a Wind Field Computer data - 1 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1996 Thesis (MS)--Virginia Polytechnic Institute and State University, 1996-07-24 Includes bibliographical references. A new software tool was needed for flight planning of a high altitude, low speed unmanned aerial vehicle which would be flying in winds close to the actual airspeed of the vehicle. An energy modeled NLP formulation was used to obtain results for a variety of missions and wind profiles. The energy constraint derived included terms due to the wind field and the performance index was a weighted combination of the amount of fuel used and the final time. With no emphasis on time and with no winds the vehicle was found to fly at maximum lift to drag velocity, Vmd. When flying in tail winds the velocity was less than Vmd, while flying in head winds the velocity was higher than Vmd. A family of solutions was found with varying times of flight and varying fuel amounts consumed which will aid the operator in choosing a flight plan depending on a desired landing time. At certain parts of the flight, the turning terms in the energy constraint equation were found to be significant. An analysis of a simpler vertical plane cruise optimal control problem was used to explain some of the characteristics of the vertical plane NLP results. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. optimization optimal control aircraft performance Virginia Tech Aerospace and Ocean Engineering Eugene M. Cliff Committee Chair Frederick H. Lutze Wayne C. Durham unrestricted http://scholar.lib.vt.edu/theses/available/etd-17616979652211/ " s1997 vau| sm 00| 0|eng d" (VPI) etd-2720162749721461 Zhu, Ping SPACE DESIGN FOR THE ACITC EDUCATIONAL TECHNOLOGY OFFICE AREA USING A WORKPLACE NEIGHBORHOOD CONCEPT Computer data - 9 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1997 Thesis (MS)--Virginia Polytechnic Institute and State University, 1997-04-25 Includes bibliographical references. Today, the workplace is undergoing dramatic changes, featuring increased team activities and informal interactions. The work place neighborhood is a design concept derived from a city planning theory that may solve the workplace design problems arising from these changes, and provided a focus for this project. The Educational Technology office area of the Advanced Communication and Information Technology Center (ACITC) possesses the features representing the general workplace tendency today. The purpose of this project was to develop a workplace neighborhood space prototype for this office area. This prototype will provide a work environment conducive to team efforts and informal interactions and a workplace neighborhood space model for future reference. The project had three design phases: design programming, design development, and design evaluation and revision. During the design programming, a survey questionnaire was distributed to all of the 12 Educational Technology employees and behavioral mapping observations were conducted. Then, a conceptual plan, a series of workplace space patterns and a floor plan were developed for the workplace neighborhood space prototype. Finally, computer models were prepared for three neighborhood units for design evaluation. The result of the design evaluation indicated that the concerns between individual and group work spaces were not solved. The space prototype was revised, and a computer model of the revised space prototype was prepared. The revised space prototype met the work patterns of the employees more closely and reflected the design concept of workplace neighborhood more clearly System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. space design workplace neighborhood Virginia Tech Housing, Interior Design and Resource Management Eric Wiedegreen Lennie Scott-Webber Joan McLain-Kark Committee Chair restricted http://scholar.lib.vt.edu/theses/available/etd-2720162749721461/ " s1997 vau| sm 00| 0|eng d" (VPI) etd-18441213972900 Yagow, Eugene R. Auxiliary Procedures for the AGNPS Model in Urban Fringe Watersheds Computer data - 10 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1997 Thesis (PHD)--Virginia Polytechnic Institute and State University, 1997-02-28 Includes bibliographical references. The Agricultural Nonpoint Source model (AGNPS) is a single-event grid-based model used for simulating runoff, sediment and nutrients from agricultural areas. This study involved using geographic information system (GIS) spatial data and functionality to improve the spatial and temporal assignment of parameter values for the AGNPS 5.0 model and incorporated methods for representing urban fringe land uses and their nonpoint source (NPS) pollution contributions in model inputs. Auxiliary procedures for modeling with AGNPS were developed both for enhancing input into the model and for enhancing modeled output. On an event basis, one procedure automated the creation of complex-formatted AGNPS 5.0 model input files using GIS as a spatial data manager. One pair of alternative procedures were developed to automate the assignment of parameter values on an event basis. One procedure used typical average annual parameter values, and the second assigned parameter values using adaptations of existing time-dependent relationships. On a monthly basis, a sequencing procedure was created to perform multiple runs with the model for a list of storms while updating parameters for each event and aggregating monthly modeled spatial output. Another pair of alternative procedures were developed to facilitate the simulation of monthly output from AGNPS modeled events. The first of these aggregated event output for all storms in each month, while the second supplemented the aggregated output with baseflow and septic system loads. The study area was the 6,500 ha urbanizing Bull Run watershed in northern Virginia, which was modeled as 14,621 cells. Databases were assembled and 109 selected storm events within a 16-year period were modeled using the above procedures. Event data were added together, where necessary, to correspond with observed data from composite-sampled intervals. Output from the two event parameterization procedures were compared with monitored loads calculated for 89 composite periods, while output from the two monthly simulation procedures were compared with monthly monitored data for 23 complete months. The monitored-modeled comparisons were considered inconclusive. Evidence strongly suggested that the rainfall records from a rain gauge outside the watershed did not correspond well with monitored runoff. The average runoff produced with the AGNPS model from the 109 selected storms amounted to 40.7% of rainfall, consistent with the calculated long-term average of 38% for the Bull Run watershed. A nonpoint source pollution index was developed to utilize monthly modeled total nitrogen, total phosphorus, and suspended sediment. Individual rating curves were developed to separately transform loads and concentrations of each pollutant into sub-index values. The maximum sub-index from each parameter was added together and averaged for the index. The index was calculated at the watershed outlet from monitored data, and in a spatially-distributed fashion along all streams from simulated output. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. geographic information systems index model interface nonpoint source pollution Virginia Tech Biological Systems Engineering Mary Leigh Wolfe John Perumpral Saied Mostaghimi Theo Dillaha James Bohland Vernon Shanholtz Committee Chair unrestricted http://scholar.lib.vt.edu/theses/available/etd-18441213972900/ " s1997 vau| sm 00| 0|eng d" (VPI) etd-2230102449761431 Yatsko, Michael S Ethnicity in Festival Landscapes: An Analysis of the Landscape of Jaialdi '95 as a Spatial Expression of Basque Ethnicity Computer data - 16 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1997 Thesis (MS)--Virginia Polytechnic Institute and State University, 1997-05-08 Includes bibliographical references. Ethnic festivals are dynamic socio-spatial phenomena in American society in which rationalized spaces are transformed into “festival space” and the cultural landscapes within the boundaries of the festivals are transfigured into festival landscapes. The landscapes of ethnic festivals generate, via a colorful assortment of cultural performances and symbols, metaphors of ethnicity and spatial expressions of social processes which influence ethnic groups. As a metaphor of ethnicity, festival landscapes have become both a tool for the ethnic boundary maintenance of ethnic groups and a form of symbolic ethnicity for many assimilated individuals. This thesis analyzes the landscape of the Basque festival, Jaialdi ’95, as a tool for the ethnic boundary maintenance for the American Basque community and the Basque colony in Boise, Idaho, and as a form of symbolic ethnicity for assimilated American Basques. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. none Virginia Tech Geography Neil L. Shumsky Kristin Addis Bonham C. Richardson Susan R. Brooker-Gross Committee Chair unrestricted http://scholar.lib.vt.edu/theses/available/etd-2230102449761431/ " s1997 vau| sm 00| 0|eng d" (VPI) etd-33501632971610 Zhou, Hongyi STRUCTURE-PROPERTY RELATIONSHIPS: MODEL STUDIES ON MELT EXTRUDED UNIAXIALLY ORIENTED HIGH DENSITY POLYETHYLENE FILMS HAVING WELL DEFINED MORPHOLOGIES Computer data - 1 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1997 Thesis (PHD)--Virginia Polytechnic Institute and State University, 1997-02-14 Includes bibliographical references. High density polyethylene (HDPE) films having simple and well-defined stacked lamellar morphology, either with or without a distinct presence of row-nucleated fibril structures, have been utilized as model materials to carry out investigations on solid state structure-property relationships. Four different subjects that were addressed are: 1) mechanical properties and deformation morphologies, 2) orientation anisotropy of the dynamic mechanical a relaxation, 3) orientation dependence of creep behavior, and 4) crystalline lamellar thickness and its distribution. For the first three topics, appropriate mechanical tests, including tensile (INSTRON), creep (TMA), and dynamic mechanical (DMTA) tests, were performed at different angles with respect to the original machine direction (MD) of the melt extruded films; morphological changes as a result of these mechanical tests were detected by WAXS, SAXS, and TEM. For the forth topic, crystalline lamellar thickness and its distribution were determined by DSC, SAXS, TEM and AFM experiments. In the large strain deformation study (chapter 4.0), samples were stretched at 00ʻ, 45ʻ and 90ʻ angles with respect to the original MD. A distinct orientation dependence of the tensile behavior was observed and correlated to the corresponding deformation modes and morphological changes, namely 1) lamellar separation and fragmentation by chain slip for the 00ʻ stretch, 2) lamellar break-up via chain pull-out for the 90ʻ stretch, and 3) lamellar shear, rotation and break-up through chain slip and/or tilt for the 45ʻ stretch. A strong strengthening effect was observed for samples with row-nucleated fibril structures at the 00ʻ stretch; whereas for the 90ʻ stretch, the presence of such structures significantly limited deformability of the samples. In the dynamic strain mechanical a relaxation study (chapter 5.0), samples were tested at nine different angles with respect to the original MD, and the morphologies of samples before and after the dynamic tests were also investigated. The mechanical dispersions for the 00ʻ and 90ʻ tests were believed to arise essentially from the crystalline phase, and they contain contributions from two earlier recognized sub-relaxations of aI and aII. While for the 45ʻ test, in addition to a high temperature aII relaxation, a interlamellar shear induced low temperature mechanical relaxation was also observed. It is concluded that the low temperature relaxation is related to the characteristics of the interface between the crystalline lamellae and amorphous layers. In the small strain creep study (chapter 6.0), samples were tested at the 00ʻ, 45ʻ and 90ʻ angles at the original MD. Both creep strain and creep rate for samples at the three angles were very different. An Eyring-rate model was utilized to analysis the observed creep behavior, and structural parameters associated with this model, including population of creep sites, activation energy and volume, were obtained by fitting the experimental data to the Eyring-rate equation. It was concluded that the plateau creep rate in these model materials is primarily controlled by the density and physical state of tie-chains in the amorphous phase. For the lamellar thickness and distribution study, DSC, SAXS, TEM and AFM experiments were conducted for samples having a well-defined stacked lamellar morphology. It was found that the most probable lamellar thickness from SAXS and TEM agreed very well; however, these values did not match with those obtained by DSC and AFM. It was pointed out that the use of DSC to determine lamellar thickness and distribution is so sensitive to heating rate and numerical values for the parameters in the Gibbs-Thomson equation that it is not believed to be suitable for quantitative analysis. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. polyethylene tensile property mechanical relaxation creep lamellar thickness Virginia Tech Materials Science and Engineering Thomas C. Ward Herve Marand Ronald G. Kander David A. Dillard Garth L. Wilkes Committee Chair unrestricted http://scholar.lib.vt.edu/theses/available/etd-33501632971610/ " s1996 vau| sm 00| 0|eng d" (VPI) etd-520112859651791 Waldhart, Chris Analysis of Tow-Placed, Variable-Stiffness Laminates Computer data - 2 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1996 Thesis (MS)--Virginia Polytechnic Institute and State University, 1996-06-05 Includes bibliographical references. It is possible to create laminae that have spatially varying fiber orientation with a tow placement machine. A laminate which is composed of such plies will have stiffness properties which vary as a function of position. Previous work had modelled such variable-stiffness laminae by taking a reference fiber path and creating subsequent paths by shifting the reference path. This thesis introduces a method where subsequent paths are truly parallel to the reference fiber path. The primary manufacturing constraint considered in the analysis of variable-stiffness laminates was limits on fiber curvature which proved to be more restrictive for parallel fiber laminae than for shifted fiber. The in-plane responses of shifted and parallel fiber variable-stiffness laminates to either an applied uniform end shortening or in-plane shear were determined. Both shifted and parallel fiber variable-stiffness laminates can redistribute the applied load thereby increasing critical buckling loads compared to traditional straight fiber laminates. The primary differences between the two methods is that parallel fiber laminates are not able to redistribute the loading to the degree of the shifted fiber. This significantly reduces the increase in critical buckling load for parallel fiber variable-stiffness laminates over straight fiber laminates. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. variable-stiffness laminates curvilinear fibers tow placement machine buckling Virginia Tech Engineering Science and Mechanics Robert M. Jones Zafer Gurdal Committee Chair Calvin Ribbens unrestricted http://scholar.lib.vt.edu/theses/available/etd-520112859651791/ " s1997 vau| sm 00| 0|eng d" (VPI) etd-301411131974430 Walker, Kenroy A. The Aspirations Formation of Disadvantaged Jamaican Male Youths Computer data - 2 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1997 Thesis (PHD)--Virginia Polytechnic Institute and State University, 1997-01-30 Includes bibliographical references. This study examined the aspirations formation of disadvantaged Jamaican male youths. The design of the study was a Type 3 holistic design which considered the global nature of multiple cases, and focused on the impact of work, family, school, peers and siblings on subjects1 aspirations. Six case studies were conducted using observations, focus groups, taped interviews and document inspection techniques. Data were analyzed using McCraken1s coding techniques. The results showed that the youths1 aspirations were leveled, reflected realities of their employment possibilities, and were patterned after their father1s occupations. The youths1 reluctance to raise their aspirations signals the need for Jamaican policy makers to address the problems caused by low aspirations among youths. Recommendations for further research are offered. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. none Virginia Tech Curriculum and Instruction Dr. Joyce Williams-Green Dr. Terry Wildman Dr. Jimmie Fortune Dr. John Burton Dr. Darrel Clowes Committee Chair unrestricted http://scholar.lib.vt.edu/theses/available/etd-301411131974430/ " s1997 vau| sm 00| 0|eng d" (VPI) etd-055132139711101 Walsh, Maryann Sheridan LOOKING AT THE PICTURE BY STEPPING OUTSIDE: A QUALITATIVE STUDY OF PARENTS' OF ADOLESCENTS EXPERIENCES IN FAMILY THERAPY Computer data - 1 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1997 Thesis (MS)--Virginia Polytechnic Institute and State University, 1997-04-03 Includes bibliographical references. Parents with adolescents often find themselves caught in the stress and strain that normally accompanies this stage of life. It is when parents cannot meet the demands of troubled adolescents that they find themselves seeking family therapy. Most of what is reported about the process of therapy continues to be from the therapist's or reseacher's perspective. There has been an increased interest in what clients have to say about their experiences. The purpose of this study was to develop a detailed description of how parents of adolescents who attended family therapy in private practice settings viewed their experiences. Fifteen parents who had been to therapy with their adolescent were recruited by their therapist to be interviewed for this study. A multicase qualitative design and constructivist theoretical framework guided the investigation. The constant comparative analysis was used to develop four core categories that described the subtitles of parents' therapeutic experience. Five case stories illustrated the core categories and parents' quotes were used to further embellish the findings. The findings included parents' experiences prior to beginning therapy, during therapy as well as reflections in retrospect. The pre-therapy presentation, based on expectations and past experiences in treatment, affected the way parents initially approached therapy. A supportive therapeutic climate was necessary for parents to trust and become open to possibilities and do the hard work required to make changes. The story of their current experience was part of the family therapy process. Parents recognized changes and what they valued about their experiences in family therapy. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. parents of adolescents clients experience qualitative study Virginia Tech Family and Child Development Sandra M. Stith, Ph.D. Eric E. mcCollum, Ph.D. Jean L. Coleman, Ed.D Karen H. Rosen, Ed.D. Committee Chair unrestricted http://scholar.lib.vt.edu/theses/available/etd-055132139711101/ " s1997 vau| sm 00| 0|eng d" (VPI) etd-1115202339731121 Borisuk, Mark T. BIFURCATION ANALYSIS OF A MODEL OF THE FROG EGG CELL CYCLE Computer data - 1 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1997 Thesis (PHD)--Virginia Polytechnic Institute and State University, 1997-04-21 Includes bibliographical references. Fertilized frog eggs (and cell-free extracts) undergo periodic oscillations in the activity of "M-phase promoting factor" (MPF), the crucial triggering enzyme for mitosis (nuclear division) and cell division. MPF activity is regulated by a complex network of biochemical reactions. Novak and Tyson, and their collaborators, have been studying the qualitative and quantitative properties of a large system of nonlinear ordinary differential equations that describe the molecular details of this system as currently known. Important clues to the behavior of the model are provided by bifurcation theory, especially characterization of the codimension-1 and -2 bifurcation sets of the differential equations. To illustrate this method, I have been studying a system of 9 ordinary differentail equations that describe the frog egg cell cycle with some fidelity. I will describe the bifurcation diagram of this system in a parameter space spanned by the rate constants for cyclin synthesis and cyclin degradation. My results suggest either that the cell cycle control system should show dynamical behavior considerably more complex than the limit cycles and steady states reported so far, or that the biochemical rate constants of the system are constrained to avoid regions of parameter space where complex bifurcation points unfold. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. cell cycle MPF bifurcation theory parameter space Virginia Tech Mathematics John A. Burns John J. Tyson Committee Co-Chair Terry L. Herdman Committee Co-Chair Kenneth P. Hannsgen Eugene M. Cliff unrestricted http://scholar.lib.vt.edu/theses/available/etd-1115202339731121/ " s1997 vau| sm 00| 0|eng d" (VPI) etd-532916102971680 Bowser, Kristina L. THE EFFECTS DAILY, MAXIMAL OF RESISTANCE EXERCISE ON MUSCULAR FUNCTION Computer data - 4 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1997 Thesis (MS)--Virginia Polytechnic Institute and State University, 1997-02-10 Includes bibliographical references. Overtraining is a common problem in athletes that prevents many from becoming đeliteø. A decrement in an athletes£ performance is usually an indicator that overtraining syndrome may be developing. Unfortunately, there is no model that can determine overtraining. A decline in performance results in a depression in maximum muscular force. It is not known whether the force depression is a result of central or peripheral factors. In this study, the two training protocols on different legs determined whether force declines are muscular (peripheral) or psychological (central). Specifically, in this study, the subjects trained one leg at maximal intensity for two weeks, and the other trained at a low intensity for two weeks. After training for two weeks, both legs were placed on a low intensity workout to monitor the recovery process. The purpose of this study was to observe muscle strength performance decrements after overtraining one leg in comparison to properly training the other leg by knee extension exercises for two weeks in trained males. Also, after overtraining the one leg for two weeks, the leg was placed on a reduced training program in order to look at recovery if overtraining occurred. Maximal force output was measured isokinetically on the Biodex three times: pre-, post-, and final test. An analysis of this data revealed no significant changes in maximal muscular force output after a high intensity training protocol. Therefore, this investigation demonstrated that overtraining in the quadricep did not result from the two weeks of high intensity resistance training. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. muscle force overtraining weight training Virginia Tech Human Nutrition Jay H. Williams Committee Chair Kerry Redican Shala E. Davis restricted http://scholar.lib.vt.edu/theses/available/etd-532916102971680/ " s1997 vau| sm 00| 0|eng d" (VPI) etd-4814221949711381 Boyd, Curtis Barton A Load-Deflection Study of Fiber-Reinforced Plastics as Reinforcement in Concrete Bridge Decks Computer data - 1 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1997 Thesis (MS)--Virginia Polytechnic Institute and State University, 1997-05-05 Includes bibliographical references. Approximately fifty percent of the bridges in the United States are considered deficient. The deterioration of the concrete components is a leading cause of the problem. The deterioration of concrete bridge decks is due primarily to corrosion of the reinforcing steel in the concrete. A promising solution to the problem is the use of fiber reinforced plastics (FRP) as a replacement for reinforcing steel. The use of FRP as reinforcement has the following advantages of lightweight, high tensile strength, corrosion resistance, flexibility, and electromagnetic resistance. This paper looks at the use of FRP as reinforcement in concrete beams and compares the information from deflection measurements of different configurations. Also, a material cost comparison is made to determine the cost of using the FRP reinforcement over standard steel reinforcement. Concrete bridge deck systems are designed using steel and fiber-reinforced plastics and allowable stress and load resistance factor methods. Recommendations for further study and uses of FRP are made. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. bridge reinforced concrete bridge design FRP fiber reinforced plastics Virginia Tech Civil Engineering Richard M. Barker Committee Chair Thomas M. Murray Richard E. Weyers unrestricted http://scholar.lib.vt.edu/theses/available/etd-4814221949711381/ " s1996 vau| sm 00| 0|eng d" (VPI) etd-394172159651721 Ward III, Allan Residual Stress Effects on Power Slump and Wafer Breakage in GaAs MESFETs Computer data - 2 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1996 Thesis (PHD)--Virginia Polytechnic Institute and State University, 1996-06-06 Includes bibliographical references. The objectives of this investigation are to develop a precise, non-destructive single crystal stress measurement technique, develop a model to explain the phenomenon known as 3power slump2, and investigate the role of device processing on wafer breakage. All three objectives were successfully met. The single crystal stress technique uses a least squares analysis of X-ray diffraction data to calculate the full stress tensor. In this way, precise non-destructive stress measurements can be made with known error bars. Rocking curve analysis, stress gradient corrections, and a data reliability technique were implemented to ensure that the stress data are correct. A theory was developed to explain 3power slump2, which is a rapid decrease in the amplifying properties of microwave amplifier circuits during operation. The model explains that for the particular geometry and bias configuration of the devices studied in this research, power slump is linearly related to shear stress at values of less than 90 MPa. The microscopic explanation of power slump is that radiation enhanced dislocation glide increases the kink concentration, thereby increasing the generation center concentration in the active region of the device. These generation centers increase the total gate current, leading to a decrease in the amplifying properties of the device. Passivation layer processing has been shown to both reduce the fracture strength and increase the residual stress in GaAs wafers, making them more susceptible to wafer breakage. Bare wafers are found to have higher fracture strength than passivated wafers. Bare wafers are also found to contain less residual stress than SiON passivated wafers, which, in turn, are found to have less stress than SiN passivated wafers. Topographic imaging suggests that SiN passivated wafers have larger flaws than SiON passivated wafers, and that the distribution of flaw size among SiN passivated wafers is wider than the distribution of flaws in SiON passivated wafers. These flaws are believed to lead to breakage of the device during processing, resulting in low fabrication yield. Both the power slump model and the wafer breakage data show that these phenomena are dependent on residual stress developed in the substrate during device fabrication. Reduction of process-induced residual stress should therefore simultaneously decrease wafer breakage rates and reduce power slump during device fabrication and operation. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. gallium arsenide MESFET wafer breakage semiconductor device x-ray diffraction stress Virginia Tech Materials Science and Engineering Robert W. Hendricks Committee Chair Avraham Amith Ronald S. Gordon Guo-Quan Lu Aicha Elshabini-Riad unrestricted http://scholar.lib.vt.edu/theses/available/etd-394172159651721/ " s1998 vau| sm 00| 0|eng d" (VPI) etd-211714251972550 Warren Jr., J.E. NONLINEAR STABILITY ANALYSIS OF FRAME-TYPE STRUCTURES WITH RANDOM GEOMETRIC IMPERFECTIONS USING A TOTAL-LAGRANGIAN FINITE ELEMENT FORMULATION Computer data - 2 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1998 Thesis (PHD)--Virginia Polytechnic Institute and State University, 1998-07-12 Includes bibliographical references. With the increasing use of lightweight frame-type structures that span long distances, there is a need for a method to determine the probability that a structure having random initial geometric imperfections will become unstable at a load less than a spe cified fraction of the perfect critical load. The overall objective of this dissertation is to present such a method for frame-type structures that become unstable at limit points. The overall objective may be broken into three parts. The first part co ncerns the development of a three-dimensional total Lagrangian beam finite element that is used to determine the critical load for the structure. The second part deals with a least squares method for modeling the random initial imperfections using the mo de shapes from a linear buckling analysis, and a specified maximum allowable magnitude for the imperfection at any imperfect node in the structure. The third part deals with the calculation of the probability of failure using a combined response surface/ first-order second-moment method. Numerical results are presented for two example problems, and indicate that the proposed method is reasonably accurate. Several problems with the proposed method were noted during the course of this work and are discuss ed in the final chapter. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. Reliability Imperfection Stability Finite Element Nonlinear Virginia Tech Engineering Science and Mechanics S. M. Holzer S. Thangjitham Committee Chair D. T. Mook D. H. Morris R. H. Plaut unrestricted http://scholar.lib.vt.edu/theses/available/etd-211714251972550/ " s1997 vau| sm 00| 0|eng d" (VPI) etd-3213172239721111 Watson, George W Beyond the Psychological Contract: Ideology and the Economic Social Contract Computer data - 4 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1997 Thesis (PHD)--Virginia Polytechnic Institute and State University, 1997-05-24 Includes bibliographical references. By combining normative philosophy and empirical social science, I craft a research framework for assessing differential expectations of economic justice within the economic social contract of the United States. I argue that distinct viewsof such a contract grounded in the tradition of individualism and communitarianism manifest in people's judgments about economic justice. We empirically test these hypotheses on a sample of 270 subjects, finding broad support for the theoretical framework. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. none Virginia Tech Management Anthony T. Cobb Richard Wokutch Carroll U. Stephens R.J. Harvey John Christman Jon M. Shepard Committee Chair unrestricted http://scholar.lib.vt.edu/theses/available/etd-3213172239721111/ " s1997 vau| sm 00| 0|eng d" (VPI) etd-1554192149731401 Weissbart, Erich J The Leached Layer Formed On Wollastonite In An Acid Environment Computer data - 6 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1997 Thesis (MS)--Virginia Polytechnic Institute and State University, 1997-04-29 Includes bibliographical references. THE LEACHED LAYER FORMED ON WOLLASTONITE IN AN ACID ENVIRONMENT Erich J. Weissbart (ABSTRACT) Experiments were carried out in a fixed-bed external recycle mixed flow reactor to measure the rate of dissolution and the development of a leached layer on wollastonite. Each experiment ran for approximately 24 hours and the release rates of Si and Ca in the interval from 14 to 24 hours were analyzed. Each experiment began with an incongruent stage where Ca was released faster than the silica that remained on the surface to form the leached layer. The silica release rate after 14 hours was 2.13 x 10-9 ( 1.03 x 10-9, 1 , n=67) mol/m2/sec, and this rate appeared to be independent of pH from pH 2 to 6 at 25 degrees C. BET surface area measurements of reacted wollastonite showed large increases in BET Asp over the course of experiments even though both the Ca and Si release rates decreased. These large increases of measured Asp were the result of the growing internal porosity of the leached layer, and much of this surface does not seem to contribute to Si release rates. From these data, we infer that the overall reaction for the hydrolysis of wollastonite in an acid environment is best explained by two relatively independent reactions. First, Ca is removed from the crystal leaving behind linear silica polymers; then the silica polymers are released into solution where they hydrolyze to form H4SiO4. nCaSiO3 + 2nH+ nCa2+ + (H2SiO3)n (H2SiO3)n + nH2O n(H4SiO4) As the leached layer grows in thickness, the Ca release rate slows because it is controlled by transport through the leached layer. A model of Ca diffusion through the leached layer shows that the leached layer grows thicker at lower pH and presents a longer diffusion path for Ca transport into the solution. This diffusion limited reaction offsets the faster rate of the Ca hydrolysis reaction so that at steady state the Ca rates should also become equal to the Si release rate. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. none Virginia Tech Geological Sciences M. F. Hochella J. R. Craig J. D. Rimstidt Committee Chair unrestricted http://scholar.lib.vt.edu/theses/available/etd-1554192149731401/ " s1998 vau| sm 00| 0|eng d" (VPI) etd-4857172839711171 Wilcox, Karen L. PRIVILEGE IN FAMILIES: COMPLEXITY IN ADULT SIBLING RELATIONSHIPS Computer data - 3 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1998 Thesis (PHD)--Virginia Polytechnic Institute and State University, 1998-07-12 Includes bibliographical references. The purpose of this study was to examine privilege in families and uncover the complexities of sibling relationships in adulthood. Through interviewing 13 adult siblings and 3 mothers from 4 families my goal was to gain a clearer picture of what privilege in families means. The sample consisted of a family with 3 sisters, a family with 3 brothers and a sister, a family with 4 brothers, and a family with 2 brothers and a sister. The adult siblings ranged in age from 30 to 60, with an average age of 42. The mothers ranged in age from 62 to 70, with an average age of 67. The study was guided by three theoretical frameworks: a life course, a phenomenological, and a feminist perspective. I conducted this study utilizing an integration of qualitative and feminist methodologies. I used a snowball sampling technique to recruit participants. Data were collected through the use of qualitative in-depth interviews. The interview guides were developed based on the research questions, the review of literature, and the theories guiding the study. I draw 5 conclusions from this study. First, there is a sense of devotion to family that is both expected and fulfilled by simply spending time together, being there for each other in times of need, and at times compromising personal needs or wants. Second, there is an overarching sense of justice that is discussed in everyday language, but at the same time referred to as "something we don't ever think about." Third, descriptions of having a continuous bond among siblings is verbalized as "being the same but different" or just feeling "something in the air," while at the same time mourning the absense of something that is "gone forever." Fourth, interviewing multiple family members extends the understanding of the difficulty of taking different stories heard by each family member and fitting them together into a "family photo." Finally, maintaining an awareness of what it is like to try to "speak for your family" has a different meaning when you also hold the knowledge that everyone else is doing the same thing--but different. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. favoritism brother parental expectations fairness sister Virginia Tech Family and Child Development Katherine R. Allen Committee Chair Joyce A. Arditti Committee Member Rosemary Blieszner Committee Member Victoria R. Fu Committee Member Michael J. Sporakowski Committee Member unrestricted http://scholar.lib.vt.edu/theses/available/etd-4857172839711171/ " s1996 vau| sm 00| 0|eng d" (VPI) etd-492119119643530 Broderick, Kevin Dee Constructing A Successful Therapeutic Experience With Adolescent Clients: A Qualitative Study Of Adolescent Experiences In Family Therapy Computer data - 1 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1996 Thesis (MS)--Virginia Polytechnic Institute and State University, 1996-12-05 Includes bibliographical references. CONSTRUCTING A SUCCESSFUL THERAPEUTIC EXPERIENCE WITH ADOLESCENT CLIENTS: A QUALITATIVE STUDY OF ADOLESCENT EXPERIENCES IN FAMILY THERAPY by Kevin Dee Broderick Committee Chair: Eric McCollum Marriage and Family Therapy (ABSTRACT) Traditionally, therapists and researchers have not asked adolescents about their family therapy experience. This qualitative study was designed to solicit in-depth feedback from adolescents who have recently participated in family therapy to broaden our understanding of their experiences in counseling. Interviews were conducted with 10 adolescents, between the ages of 14 and 20, to discover what helps teenagers have a successful family therapy experience. From the interviews, five main categories emerged; (1) client/therapist relationship, (2) talking and being heard in both individual and family sessions, (3) gaining insight during therapy, (4) taking personal responsibility for making therapy work, and (5) seeing positive results. Feedback from the adolescents is used to suggest ways family therapists might enhance their effectiveness with adolescent clients and a model for treatment success is presented. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. none Virginia Tech Family and Child Development K. H. Rosen J. U. Coleman S. M. Stith E. E. McCollum Committee Chair unrestricted http://scholar.lib.vt.edu/theses/available/etd-492119119643530/ " s1996 vau| sm 00| 0|eng d" (VPI) etd-314610359611541 Bruner, Christopher William Stuteville PARALLELIZATION OF THE EULER EQUATIONS ON UNSTRUCTURED GRIDS Computer data - 1 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1996 Thesis (PHD)--Virginia Polytechnic Institute and State University, 1996-05-01 Includes bibliographical references. Several different time-integration algorithms for the Euler equations are investigated on two distributed-memory parallel computers using an explicit message-passing paradigm: these are classic Euler Explicit, four-stage Jameson-style Runge-Kutta, Block Jacobi, Block Gauss-Seidel, and Block Symmetric Gauss-Seidel. A finite-volume formulation is used for the spatial discretization of the physical domain. Both two- and three-dimensional test cases are evaluated against five reference solutions to demonstrate accuracy of the fundamental sequential algorithms. Different schemes for communicating or approximating data that are not available on the local compute node are discussed and it is shown that complete sharing of the evolving solution to the inner matrix problem at every iteration is faster than the other schemes considered. Speedup and efficiency issues pertaining to the various time-integration algorithms are then addressed for each system. Of the algorithms considered, Symmetric Block Gauss-Seidel has the overall best performance. It is also demonstrated that using parallel efficiency as the sole means of evaluating performance of an algorithm often leads to erroneous conclusions; the clock time needed to solve a problem is a much better indicator of algorithm performance. A general method for extending one-dimensional limiter formulations to the unstructured case is also discussed and applied to Van Albada's limiter as well as Roe's Superbee limiter. Solutions and convergence histories for a two-dimensional supersonic ramp problem using these limiters are presented along with computations using the limiters of Barth & Jesperson and Venkatakrishnan--the Van Al-bada limiter has performance similar to Venkatakrishnan's. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. unstructured grids parallel algorithms computational fluid dynamics Virginia Tech Aerospace and Ocean Engineering Joseph G. Hoeg William L. Devenport Joseph A. Schetz Bernard Grossman Robert W. Walters Committee Chair unrestricted http://scholar.lib.vt.edu/theses/available/etd-314610359611541/ " s1996 vau| sm 00| 0|eng d" (VPI) etd-461113689652491 Wilson II, Lawriston A Prediction of Fertility of Virginia Beef Heifers Using Expert Systems Technology Computer data - 1 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1996 Thesis (MS)--Virginia Polytechnic Institute and State University, 1996-08-16 Includes bibliographical references. An expert system to predict the fertility of beef heifers was developed using the A.I. Toolkit KAPPA-PC 2.33. The knowledge base was developed from scientific literature and from a beef cattle reproduction expert. The expert system computes an evaluation age, age both at the start and end of the breeding season, and weight per day of age to classify a heifer as having either a 3LOW2, 3GOOD2, or 3EXCELLENT2 likelihood of conception. The expert system summarizes the information that is entered into the computer and creates a text file of the summary. It also gives explanations for every prediction to help identify and alleviate any problem areas that may affect a heifer1s ability to reproduce. The program requires an IBM compatible computer installed with Windows 3.13 or greater. From simulated data for purebred or crossbred British cattle, there was 72% prediction agreement between the expert system and the expert. From analysis of historical data of Hereford-Angus crossbred cattle, heifers categorized as 3LOW2 and 3GOOD2 had significantly higher observed pregnancy rates than expected for each category. There was no significant difference between observed and expected pregnancy rates for heifers in the 3EXCELLENT2 category. Pregnancy rates for post-weaning and pre-breeding evaluations for the 3LOW2 heifers were found to be lower from the combined 3GOOD2 and 3EXCELLENT2 heifers at P=.03 and P=.06 respectively. Observed successful calving rates for heifers categorized as 3LOW2, 3GOOD2, and 3EXCELLENT2 did not differ significantly from the expected calving rates for each category. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. artificial intelligence beef cattle biological type reproduction Virginia Tech Animal & Poultry Sciences W. E. Beal Conrad D. Heatwole William D. Hohenboken Committee Chair unrestricted http://scholar.lib.vt.edu/theses/available/etd-461113689652491/ " s1997 vau| sm 00| 0|eng d" (VPI) etd-91432539751141 Favor, Craig M. Evaluation of A "Floating" Aerobics Floor Computer data - 9 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1997 Thesis (MS)--Virginia Polytechnic Institute and State University, 1997-04-11 Includes bibliographical references. Aerobics dance floors often produce annoying floor vibrations in adjacent parts of a building due to the rhythmic impact of the aerobicists. Various types of shock absorbing aerobics and dance floors are widely used to prevent injuries to the participants, but the floors may not prevent vibrations in adjacent areas of the building. The purpose of this investigation is to evaluate a temporary "floating" concrete aerobics floor designed to prevent the force and vibrations induced by rhythmic exercises from being transmitted to the existing building floor system. The test floor is a concrete slab mounted on pressurized air springs. A series of tests was conducted to determine the vibration characteristics of the floor and the forces transferred to the supporting floor system. Experienced aerobicists compared the response of the "floating" floor to existing aerobics floors. Based on the experimental results, vibration characteristics and a prediction of the force transmitted to the supporting floor by the "floating" floor system were determined. Recommendations are made in terms of the feasibility of the "floating" floor concept, additional testing to be performed, and possible applications. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. none Virginia Tech Civil Engineering Thomas M. Murray Committee Chair David E. Allen Richard M. Barker Raymond H. Plaut unrestricted http://scholar.lib.vt.edu/theses/available/etd-91432539751141/ " s1997 vau| sm 00| 0|eng d" (VPI) etd-17391653976940 Buck, Sharon Perkins Applying Probabilistic Risk Assessment to Agricultural Nonpoint Source Pollution Computer data - 1 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1997 Thesis (MS)--Virginia Polytechnic Institute and State University, 1997-01-30 Includes bibliographical references. A probabilistic risk assessment (PRA) for the discharge of excessive nitrogen from nonpoint sources (NPSs) to a stream was performed for a small agricultural watershed in northern Virginia. Risk, by definition, is the product of the frequency of occurrence of an event and the consequences of that event. The purpose of this research was to determine the probability of occurrence of a nitrogen discharge event (i.e., frequency). The consequences of such a discharge event were not explicitly determined but were implicitly assumed to be negative in nature. An event tree was developed to show the basic hydrologic processes at work in a small watershed. However, the event tree could not be used to discover the causes for nitrogen loss from the watershed. Therefore, a fault tree was developed for excessive nitrogen discharge in surface runoff on any day from agricultural sources. The development of the fault tree was found to be a useful exercise in understanding the intricate cause and effect relationships between agricultural practices and NPS pollution. Based on the results, the fault tree methodology might be used as an effective teaching or communication tool. The fault tree was also evaluated quantitatively to determine a probability of occurrence for excessive nitrogen discharge to the stream on any day. Land use, fertilization, monitoring, and long-term weather records were used in conjunction with scientific judgment and expert opinion to establish the probabilities within the fault tree and to calculate the overall probability of nitrogen discharge to the stream on any day. The results obtained from the fault tree calculations tend to underestimate the importance of cropland best management practices (BMPs) over the long term, because the fault tree was developed on a daily basis (i.e., every day in a year has the same probability of a discharge event occurring). A more accurate depiction of the NPS pollution control problem was achieved by assuming the occurrence of a runoff event. A second fault tree was presented for the discharge of excessive nitrogen to the stream during a runoff event. The quantitative assessment of the new fault tree showed more clearly the impact of BMPs on reducing the likelihood of nitrogen discharge. A 0.15 decrease in the probability of nitrogen discharge during a runoff event was calculated for the Owl Run watershed from 1987 to 1993 due to the effects of BMPs installed during that time period. A 0.20 decrease was calculated for an Owl Run subwatershed for the same time period. This subwatershed isolated two major dairy operations and the effects of the BMPs installed for those dairies. Despite the success of the fault tree in mirroring changes within the watershed, the amount of data and time required to perform the quantitative assessment may limit its use in the NPS pollution control field. The basic nature of the fault tree technique also limits its usefulness in the field. One such limitation is that degrees of events cannot be expressed. For example, a BMP is either present or not present on a fault tree. There can be no indication of how effective the BMP is in preventing NPS pollution without substantially increasing the level of detail displayed by the tree. Another limitation is that the ultimate result of the fault tree calculations is a probability of occurrence. This value is not as easily understood as the output of NPS pollution computer models, for example, where the output has specific meaning and units (e.g., milligrams of nitrogen per liter of runoff). The qualitative fault tree, however, has the advantage over computer models when it comes to understanding the concepts behind the technique and being able to see the cause and effect relationships at work in the watershed. Laypersons can understand the fault tree more easily than the complex computer code and intricate equations of models. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. probabilistic risk assessment nonpoint source pollution Virginia Tech Biological Systems Engineering Mary Leigh Wolf Committee Chair Frank E. Woeste John V. Perumpral Donald M. Vietor Saied Mostaghimi unrestricted http://scholar.lib.vt.edu/theses/available/etd-17391653976940/ " s1998 vau| sm 00| 0|eng d" (VPI) etd-31251021109643250 Wittmer, Kenneth S Turbulent flowfield downstream of a perpendicular airfoil--vortex interaction Computer data - 1 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1998 Thesis (PHD)--Virginia Polytechnic Institute and State University, 1998-08-12 Includes bibliographical references. Experiments were performed to document the turbulent flowfield produced downstream of an airfoil encountering an intense streamwise vortex. This type of perpendicular airfoil--vortex interaction commonly occurs in helicopter rotor flows. The experiments presented here thus provide useful information for the prediction of helicopter noise, particularly BWI noise. Three-component velocity and turbulence measurements were made in unprecedented detail using a computerized miniature four-sensor hot-wire probe system; revealing much about the structure and behavior of this flow over a range of conditions. The interaction between the vortex and the airfoil wake leaves the vortex surrounded by a large region of intense turbulence unlike the turbulence surrounding an isolated vortex. Even for close separations, the vortex core passes the airfoil virtually unchanged. However, vorticity of opposite sign is shed by the airfoil in response to the angle of attack distribution induced by the vortex resulting in an unstable circulation distribution according to Rayleigh's criterion. Simple theoretical models adequately describe the shed vorticity distribution of the airfoil and the unstable circulation distribution it imparts on the vortex. As the flow develops, the vortex continuously distorts the airfoil wake. The strain rates imparted by the vortex on the spanwise vorticity contained in the airfoil wake result in an anisotropic, turbulence producing stress field. For several chord lengths downstream, the vortex core remains laminar and little change is seen in the unstable circulation distribution. While the vortex core is laminar, turbulent fluctuations measured in the core are the result of inactive wandering motions and the characteristic length and velocity scales of the flat portion of the vortex wake appear to be appropriate scales for the fluctuations. Eventually, the vortex core becomes turbulent as indicated by an increase in high frequency velocity fluctuation levels of more than an order of magnitude. Subsequently, the circulation distribution reorganizes to a stable distribution. A loss in core circulation occurs due to a decrease in the peak tangential velocity which is proportionately larger than the increase in the vortex core radius. The peak tangential velocity decreases to the point where it is exceeded by the axial velocity deficit---another unstable situation. These effects increase with decreased separation between the vortex and the airfoil, but appear to be largely independent of airfoil angle of attack an only weakly dependent upon vortex strength. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. vortex turbulence BWI helicopter noise hot-wire Virginia Tech Aerospace and Ocean Engineering Roger L. Simpson Saad A. Ragab Wayne L. Neu William H. Mason William J. Devenport Committee Chair unrestricted http://scholar.lib.vt.edu/theses/available/etd-31251021109643250/ " s1997 vau| sm 00| 0|eng d" (VPI) etd-23349150973140 Cameron, Rick A. Fixed-Point Implementation of a Multistage Receiver Computer data - 1 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1997 Thesis (PHD)--Virginia Polytechnic Institute and State University, 1997-01-13 Includes bibliographical references. This dissertation provides a study of synchronization and quantization issues in implementing a multistage receiver in fixed-point Digital Signal Processing (DSP) hardware. Current multistage receiver analysis has neglected the effects of synchronization and quantization; however, these effects can degrade system performance and therefore decrease overall system capacity. The first objective is to analyze and simulate various effects of synchronization in a multistage system. These effects include the effect of unsynchronized users on the bit error rate (BER) of synchronized users, and determining whether interference cancellation can be used to improve the synchronization time. This information is used to determine whether synchronization will limit overall system capacity. Both analytical and simulation techniques are presented. The second objective is to study the effects of quantization on the performance of the multistage receiver. A DSP implementation of a practical receiver will require a DSP chip with a fewer number of bits than the computer chips typically used in simulation of receiver performance. Therefore, the DSP implementation performs poorer than the simulation results predict. In addition, a fixed-point implementation is often favored over a floating-point implementation, due to the high processing requirements necessitated by the high chip rate. This further degrades performance because of the limited dynamic range available with fixed-point arithmetic. The performance of the receiver using a fixed-point implementation is analyzed and simulated. We also relate these topics to other important issues in the hardware implementation of multistage receivers, including the effects of frequency offsets at the receiver and developing a multiuser air protocol interface (API). This dissertation represents a contribution to the ongoing hardware development effort in multistage receivers at Virginia Tech. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. interference cancellation quantization synchronization CDMA Virginia Tech Electrical and Computer Engineering John Kobza Brian Woerner Committee Chair Hugh VanLandingham Jeffrey H. Reed Theodore Rappaport unrestricted http://scholar.lib.vt.edu/theses/available/etd-23349150973140/ " s1997 vau| sm 00| 0|eng d" (VPI) etd-431616132974710 Wolf, Bettina Revealing Essence Computer data - 2 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1997 Thesis (MA)--Virginia Polytechnic Institute and State University, 1997-01-31 Includes bibliographical references. There is a fine line between the "simple" and the "simplistic". The simple such as the plain, the pure, and the truthful holds a complexity within, which is extremely hard to obtain. It ultimately results in beauty. The simplistic embodies nothing more than obviousness and boredom. My aim is to strive for simple beauty. Concerning objects and architecture, to simplify means to reduce by eliminating the superficial and the superfluous, to unmask what is essential. Quality materials and craftsmanship are prerequisites. In combination with the accuracy of the design they help to attain the desired result which speaks of precision and clarity. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. wolf simplicity simple beauty art gallery Virginia Tech Architecture Michael OBrien Frank Weiner Heinrich Schnoedt Robert J. Dunay Committee Chair restricted http://scholar.lib.vt.edu/theses/available/etd-431616132974710/ " s1997 vau| sm 00| 0|eng d" (VPI) etd-358103049751491 Cary, Charles William III Effective Lengths of Web-Tapered Columns in Rigid Metal Building Frames Computer data - 1 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1997 Thesis (MS)--Virginia Polytechnic Institute and State University, 1997-05-27 Includes bibliographical references. Current procedures for estimating effective length factors for web-tapered members rely heavily on the use of charts and graphs. This makes them difficult to implement using a computer. In addition, they are often based on unrealistic assumptions. In cases where these assumptions are not satisfied, design errors may result. This investigation proposes a modification to an effective length factor expression developed by Lui (1992). This modification allows the expression to be applied to web-tapered members with good accuracy. A derivation of the proposed expression is presented, and the results obtained by applying the expression to a range of frames are compared to the results obtained from second-order finite element analyses. Calculations involved in using the expression are presented. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. tapered effective length metal building column Virginia Tech Civil Engineering W. Samuel Easterling Thomas M. Murray Committee Chair Siegfried M. Holzer unrestricted http://scholar.lib.vt.edu/theses/available/etd-358103049751491/ " s1996 vau| sm 00| 0|eng d" (VPI) etd-5155161059611611 Case, Scott Wayne Mechanics of Fiber-Controlled Behavior in Polymeric Composite Materials Computer data - 1 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1996 Thesis (PHD)--Virginia Polytechnic Institute and State University, 1996-05-28 Includes bibliographical references. Modern durability and damage tolerance predictions for composite material systems rely on accurate estimates of the local stress and material states for each of the constituents, as well as the manner in which the constituents interact. In this work, an number of approaches to estimating the stress states and interactions are developed. First, an elasticity solution is presented for the problem of a penny-shaped crack in an N-phase composite material system opened by a prescribed normal pressure. The stress state around such a crack is then used to estimate the stress concentrations due to adjacent fiber fractures in a composite materials. The resulting stress concentrations are then used to estimate the tensile strength of the composite. The predicted results are compared with experimental values. In addition, a cumulative damage model for fatigue is presented. Modifications to the model are made to include the effects of variable amplitude loading. These modifications are based upon the use of remaining strength as a damage metric and the definition of an equivalent generalized time. The model is initially validated using results from the literature. Also, experimental data from APC-2 laminates and IM7/K3B laminates are used in the model. The use of such data for notched laminates requires the use of an effective hole size, which is calculated based upon strain distribution measurements. Measured remaining strengths after fatigue loading are compared with the predicted values for specimens fatigued at room temperature and 350ʻF (177ʻC). System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. durability damage tolerance micromechanical models composite materials fatigue strength prediction life prediction Virginia Tech Engineering Science and Mechanics Scott L. Hendricks Richey M. Davis Surot Thangjitham Demetri P. Telionis Kenneth L. Reifsnider Committee Chair unrestricted http://scholar.lib.vt.edu/theses/available/etd-5155161059611611/ " s1996 vau| sm 00| 0|eng d" (VPI) etd-4924178109653120 Cato, Mary E. The Limits of Law as Technology for Environmental Policy: A Case Study of the Bronx Community Paper Company Computer data - 1 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1996 Thesis (MS)--Virginia Polytechnic Institute and State University, 1996-09-28 Includes bibliographical references. This thesis examines environmental law as a social technology, using approaches from science and technology studies, including methods for studying controversies as well as actor-network and technology transfer concepts. Legal technologies, including statutes, regulations, and lawsuits, have become significant participants in United States environmental policy. That policy developed during the twentieth century in response to contrasting concerns about nature (development of natural resources vs. protection of native species and wilderness), along with growing concern about urban environmental issues (such as air and water quality), and waste disposal). The environmental movement that began after World War II gained power with provisions incorporated into 1970s environmental legislation allowing citizens to sue polluting industries and corporations. Opposition to environmentalism developed in the 1980s, as wise use and property rights movements seeking to expand development of natural resources, and an environmental justice movement concerned with issues and constituencies not addressed by mainstream environmental organizations. As a result of that opposition, the environmental movement in the United States has strengthened, and broadened both the memberships in varied organizations and the range of issues addressed. A case study of the Bronx Community Paper Company provides an example of the current state of environmental law and policy in the United States, and the limited ability of legal technologies to resolve increasingly complex environmental controversies. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. social technology controversy studies environmental law actornetwork technology transfer Virginia Tech Science & Technology Studies Richard F. Hirsh Marianne K. De Laet Committee Co-Chair Mark V. Barrow, Jr. Committee Co-Chair unrestricted http://scholar.lib.vt.edu/theses/available/etd-4924178109653120/ " s1996 vau| sm 00| 0|eng d" (VPI) etd-34131420119653540 Wooster, Roland Peter Optimizing Response Time, Rather than Hit Rates, of WWW Proxy Caches Computer data - 2 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1996 Thesis (MS)--Virginia Polytechnic Institute and State University, 1996-12-19 Includes bibliographical references. This thesis investigates the possibility of improving World Wide Web (WWW) proxy cache performance. Most published research on proxy caches is concerned only with improving the cache hit rate. Improving only the hit rate, however, ignores the actual retrieval times experienced by WWW browser users. This research investigates removal algorithms that consider the time to download a file as a factor. Our experiments show that a removal algorithm that minimizes only the download time yields poor results. However, a new algorithm is investigated that does provide improved performance over common removal algorithms using three factors --- the speed at which a file is downloaded, the size of the file, and the number of references to the file (the number of hits). Experiments are conducted with a modified version of the Harvest Cache which has been made available on the Internet from the Virginia Tech Network Research Group's (VT-NRG) home page. WWW traffic from the ".edu" domain is used in all of the experiments. Five different removal algorithms are compared: least recently used, least frequently used, document size, and two new algorithms. The results indicate that the new three factor algorithm reduces the average latency experienced by users. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. none Virginia Tech Computer Science Dr. Scott Midkiff Dr. Edward Fox Dr. Marc Abrams Committee Chair unrestricted http://scholar.lib.vt.edu/theses/available/etd-34131420119653540/ " s1996 vau| sm 00| 0|eng d" (VPI) etd-2455212097410 Cerezo, Graciela M. Solution Representation and Indentification for Singular neutral Functional Differential Equations Computer data - 1 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1996 Thesis (PHD)--Virginia Polytechnic Institute and State University, 1996-12-06 Includes bibliographical references. The solutions for a class of Neutral Functional Differential Equations (NFDE) with weakly singular kernels are studied. Using singular expansion techniques, a representation of the solution of the NFDE is obtained by studing an associated Volterra Integral Equation. We study the Collocation Method as a projection method for the approximation of solutions for Volterra Integral Equations. Particulary, the possibility of achieving higher order approximations is discussed. Special attention is given to the choice of the projection space and its relation to the smoothness of the approximated solution. Finally, we study the identification problem for a parameter appearing in the weakly singular operator of the NFDE. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. integral equations neutral functional differential equations parameter identification collocation method Virginia Tech Mathematics John A. Burns Eugene M. Cliff Jeffrey Borggaard Terry L. Herdman Committee Chair David L. Russell unrestricted http://scholar.lib.vt.edu/theses/available/etd-2455212097410/ " s1997 vau| sm 00| 0|eng d" (VPI) etd-2638232149731401 Chandran, Rakesh Sarasamma INFLUENCE OF ISOXABEN APPLICATION TIMING ON DISSIPATION AND BROADLEAF WEED CONTROL IN TURF Computer data - 7 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1997 Thesis (PHD)--Virginia Polytechnic Institute and State University, 1997-04-30 Includes bibliographical references. Isoxaben is a preemergence (PRE) broadleaf herbicide used in turf and ornamentals. Field, greenhouse, and laboratory research evaluated this herbicide for PRE control of selected broadleaves in turf, suspected postemergence (POST) herbicidal effects, and the influence of application timings and rates on soil residual. During seed germination in moist filter paper, isoxaben concentrations required for 50% inhibition of radicle growth (GR50) were 0.013, 0.010, 0.008, 0.008, and 0.007 ppm for dandelion, buckhorn plantain, white clover, black medic, and common lespedeza, respectively. In greenhouse experiments, isoxaben applied POST at 2.24 kg ai/ha suppressed the growth of Florida betony, black medic and white clover by 45, 65, and 66%, respectively, and reduced regrowth of Florida betony by 71%. In soil bioassays, yellow rocket control from isoxaben applied in fall was approximately 20 and 30% greater than spring-applied isoxaben at 3 and 6 MAT, respectively. Buckhorn plantain control from fall treatments at 3 MAT was approximately 15% higher than spring-applied isoxaben at 3 MAT. Application timings did not influence control of spotted spurge, a less sensitive weed. Isoxaben applied to turf in spring at 1.12 kg/ha provided > 90% control of buckhorn plantain, dandelion, and corn speedwell at 4 MAT. Fall applied isoxaben at the same rate provided total control of common chickweed, corn speedwell and henbit at 3 MAT and 80 to 90% control of white sweet clover and buckhorn plantain that germinated the following spring. Double (spring followed by fall) application of isoxaben to turf appeared to enhance broadleaf weed control in some instances. Dissipation of isoxaben in the top 3.8 cm of a Ross silt-loam soil as affected by spring, fall, and spring followed by fall applications was determined using high performance liquid chromatography (HPLC) analysis. Isoxaben residues in soil decreased by 55 and 92% by 3 and 6 MAT, respectively, for spring treatments, and decreased 29 and 52% by 3 and 6 MAT for fall treatments, respectively. A soil-bioassay study correlated well with chemical analysis of isoxaben residues, as the correlation coefficients were 0.85 and 0.89 for yellow rocket and buckhorn plantain, respectively. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. degradation herbicide fate preemergence half-life Virginia Tech Plant Pathology Roderick W. Young E. Scott Hagood S. Wayne Bingham Committee Co-Chair Jeffrey F. Derr Committee Co-Chair John R. Hall III unrestricted http://scholar.lib.vt.edu/theses/available/etd-2638232149731401/ " s1996 vau| sm 00| 0|eng d" (VPI) etd-492413240975230 Wolter, Matthias Regional Stormwater Management Facility System at the School of Veterinary Medicine, Blacksburg, Virginia Computer data - 5 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1996 Thesis (MS)--Virginia Polytechnic Institute and State University, 1996-03-12 Includes bibliographical references. Continuing development of the Virginia Tech campus is increasing downstream flooding and water quality problems. To address these problems, the University has proposed the construction of a stormwater management facility to control the quantity and quality of stormwater releases to Strouble Creek, a tributary of the New River. The overall goal of this project is to design a stormwater management facility proposed for the Virginia-Maryland College of Veterinary Medicine at Virginia Tech in Blacksburg, Virginia that will reduce present and anticipated downstream flooding and water quality problems. Specific objectives of the project are: ʺ control of flooding in lower areas by reducing the peak discharge while disturbing existing wetlands as little as possible, ʺ address removal of major NPS pollutants such as total phosphorus (TP), total nitrogen (TN), metals, organic compounds related to petroleum and gasoline, and suspended sediment (SS) from stormwater runoff, and ʺ design of a dam system that is able to withstand all driving forces and constructed in accordance with governing regulations. The design requirement to limit wetland disturbance below one acre was maintained. The requirement set by officials of Virginia Tech is based on the Nationwide Permit 26 of the Wetland Regulations. An individual permit process is thus avoided. Considering this demand, however, the freedom of the stormwater management facility design was significantly restricted. Resulting from the previous restrictions mentioned, the facility will include two ponds in series - a lower, dry pond and an upper, wet pond. The stormwater management system is designed to reduce the peak discharge. The dry pond is designed to detain water only for a short period of time, as opposed to the wet pond which is designed to retain water, thereby maintaining a permanent pool of water, and to change the characteristics of runoff. The wet pond was chosen to be of an Extended Detention wetland type. Aspects such as the availability of suitable area and detention volume governed the decision to make use of this type of stormwater wetland. The constraint on a maximum possible water surface elevation due to the Veterinary School1s road embankment, which crest elevation is at 2023 ft, was considered in the design. The stormwater management facility was designed to meet water quantity control requirements and to address water quality benefits. Storm water management regulations intending to mitigate the adverse effects of land development to streams and waterways were met. Requirements to limit peak discharges from 2-year and 10-year events to existing discharge levels were achieved. Several outlet structures for each of the ponds were investigated. The structures proposed are a perforated riser/broad-crested weir for the wet pond and a proportional weir for the dry pond. They were chosen as a result of analyses on hydraulic performance, maximum water surface elevations, drawdown times, peak discharge rates, and pollutant removal capabilities. The average pollutant removal capability of 75% of TSS, 45% TP, and 25% TN for an extended stormwater wetland, as found in the literature, is expected to be lower for the proposed facility, since the wetland-to-watershed-area ratio is considerably smaller (0.22%) than the required minimum ratio of 1%. However, other suggested desirable parameter for extended detention wetland systems such as required treatment volume, effective flow path length, and dry weather water balance will be maintained. The structural design of the dams was based on experience and research data. The dams are designed to consist of two zones, shell and core. The core extends as a cutoff trench 4 feet below the ground surface. Additionally, toe drain trenches and anti-seep collars along the pipe where penetrating the dam will be placed to collect and reduce seepage, respectively. Special considerations toward seepage problems were taken into account for both dams by placing a cutoff trench and a toe drain trench. Note: The appendix of this project report contains four AutoCAD files, that can only be viewed using AutoCAD. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. HEC-1 Dam Basin Outlet Structures Wetland Stormwater Detention Facility VT/PSUHM Virginia Tech Biological Systems Engineering Dillaha III, Theo A. Committee Chair Kibler, David F. Marsh, Lori S. unrestricted http://scholar.lib.vt.edu/theses/available/etd-492413240975230/ " s1997 vau| sm 00| 0|eng d" (VPI) etd-24131773971961 Cheng, Patty W. Effective Use of MRP-Type Computer Systems to Support manufacturing Computer data - 1 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1997 Thesis (MS)--Virginia Polytechnic Institute and State University, 1997-03-19 Includes bibliographical references. Within the last 30 years, Manufacturing Resource Planning (MRP-type) computer systems have quickly evolved from basic materials requirement planning software to today’s enterprise resource planning (ERP) integrated software packages that reside on client/server computer architecture. However, given the magnitude of influence these computer systems encompass, very little research has been conducted to monitor and improve how companies are actually using these MRP, advanced MRP and ERP computer systems. In practical terms, where is the typical manufacturing organization today in terms of MRP systems development? To what extent is software being applied for use in enterprise integration? A survey study of manufacturing companies in Virginia and Tennessee was conducted to evaluate the current use and performance of computer systems to support manufacturing applications. This study explores the reasons why organizations chose to use these systems, the problems and benefits derived from the MRP/ERP systems, and the characteristics of the types of companies that have benefited from the use of MRP-type systems. The survey participants evaluated the performance of their manufacturing or enterprise planning systems on the basis of data accuracy, customer satisfaction, user satisfaction, systems effectiveness, convenience, information relevance, and software reliability. Furthermore, success factors associated with organizational performance were tested and evaluated. The correlation between perceived performance was tested against the influence of upper management support, the level of emphasis on training, sources of technical expertise, and organizational experience with MRP-type systems. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. manufacturing computer systems organizational performance enterprise resource planning (ERP) MRP usage Virginia Tech Industrial and Systems Engineering Dr. C. Patrick Koelling Committee Chair Dr. Brian M. Kleiner Dr. Ralph D. Badinelli unrestricted http://scholar.lib.vt.edu/theses/available/etd-24131773971961/ " s1996 vau| sm 00| 0|eng d" (VPI) etd-195610359611541 Farrar, Angela L. It's All About Relationships: African-American and European-American Women's Hotel Management Careers Computer data - 1 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1996 Thesis (PHD)--Virginia Polytechnic Institute and State University, 1996-02-19 Includes bibliographical references. Among the 44000-plus general managers employed in United States' hotels in 1993, there were only 100 women, 15 African-Americans, and three African-American women. Additionally, less than 0.5 percent of corporate hospitality managers were women. Given this relative underrepresentation of European-American women and African-Americans, combined with the increasing diversity of hotel clientele and service providers, the purpose of this study is to broaden our understanding of the sources of inequitable occupational outcomes among race-gender groups in hotel management. Two research questions addressed are addressed (1) How are hotel management careers racialized and gendered?; and (2) How are the career experiences of African-American women who are hotel managers different from those of European-American women who are managers? A grounded hermeneutic research approach of joint collection, analysis, and contextualized interpretation of data was used. The data were collected using semi-structured interviews with ten African-American women and five European-American women who are hotel managers. The constant comparative method of analysis yielded 58 critical difference defining incidents in which the women's race and gender influenced their career experiences. Further analysis of these incidents yielded four conceptual categories: career stages, relationships, power resources, and human resource management practices. The women's careers were racialized and gendered through (1) their relationships to European-American men, which (2) provided the women with different resources at each stage of their careers and (3) influenced the way their superiors, who were predominantly European-American men, applied human resource practices. The differences in the career experiences of the women who participated in this study were largely a result of their different positions in relation to European-American men. These relationships to European-American men were significant as the women described these men as "having an inborn advantage in this industry" and as "running things." In the final chapter, I suggest actions hospitality practitioners, educators, and researchers can take to address several factors identified as contributing to the creation of inequitable career outcomes. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. hotel manager career race gender Virginia Tech Hospitality and Tourism Management S. K. Murrmann Committee Chair T. Calasanti R. Minish S. M. Nkomo M. Rafig J. F. Williams-Green unrestricted http://scholar.lib.vt.edu/theses/available/etd-195610359611541/ " s1996 vau| sm 00| 0|eng d" (VPI) etd-351189119613430 Wu, Veronica Tong Chemical, Physical and Sensory Characteristics of Lactose-reduced Baked Custards Made with a Low-fat, Low-cholesterol Egg Substitute Computer data - 4 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1996 Thesis (MS)--Virginia Polytechnic Institute and State University, 1996-09-24 Includes bibliographical references. Two experiments were conducted to examine the effects of type of milk (whole; nonfat; nonfat, 70% lactose-reduced) and type of egg (fresh, whole egg; egg substitute) on the quality of baked custards. The egg substitute was a combination of dried egg whit e solids, dried low-fat, low-cholesterol egg yolk solids, and xanthan gum. Custard formulations served as prototypes for use in studies conducted in the Department of Food Science and Technology, Virginia Tech. In those studies, the effects of processing parameters on the quality of the custards were examined. The goal of all the studies was to develop shelf-stable lactose-reduced custard mixes that have potential for use in the foodservice industry. In Experiment I, chemical, physical, and sensory characteristics of a dessert type baked custard, made with sucrose, were examined. In Experiment II, the same characteristics were examined for a cheese flavored, entree type custard made without sucrose. Results indicate that use of nonfat and nonfat, 70% lactose-reduced milk in place of whole milk decreased significantly total fat and cholesterol concentrations in both types of custard mixes. Lactose-reduced milk also decreased lactose and increased gala ctose concentrations. The egg substitute decreased total fat and cholesterol concentrations and increased protein concentration. In general, lactose reduction had little effect on the physical and sensory characteristics of both types of custards, but the egg substitute affected these characteristics. Custards made with the egg substitute had less intense yellow color and greater gel strength than those made with fresh, whole egg. These custards also were less bright and more uneven in color and had weake r egg flavor and aftertaste. Based on results of this study, development of a lactose-reduced custard is feasible. However, additional studies are needed to examine potential for use of the formulations in the foodservice industry. Because the mixes could be used as bases for other types of products, such as custard pies, filled pastries, and quiches, studies that focus on development of those products could help define the niche for the mixes in the foodservice industry. Because of the trend in today1s market for reduced-fat, reduc ed-cholesterol foods, additional studies could be done to examine the effects of various types of egg substitutes on the quality of the custards. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. custard lactose intolerance elderly sensory evaluation egg substitute Virginia Tech Human Nutrition William E. Barbeau Susan E. Duncan Denise Brochetti Committee Chair restricted http://scholar.lib.vt.edu/theses/available/etd-351189119613430/ " s1996 vau| sm 00| 0|eng d" (VPI) etd-234115969621901 Cherbaka, Mark F. Verification and Configuration of a Run-Time Reconfigurable Custom Computing Integrated Circuit for DSP Applications Computer data - 1 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1996 Thesis (MS)--Virginia Polytechnic Institute and State University, 1996-07-08 Includes bibliographical references. In recent years, interest in the area of custom computing machines (CCMs) has been on a steady increase. Much of the activity surrounding CCMs has centered around Field-Programmable Gate Array (FPGA) technology and rapid prototyping applications. While higher performance has been a concern in some applications, the solutions are limited by the relatively small FPGA bandwidth, density and throughput. This leads to area, speed, power, and application-specific constraints. In recent months, an integrated circuit known as the VT Colt has been developed to address some high performance digital signal processing (DSP) problems that conventional processors, CCMs, and ASICs cannot do under the space and power constraints. The Colt chip takes a data-flow approach to processing and is highly reconfigurable to suit the many computationally demanding tasks that new DSP applications present. A significant portion of the development of the Colt chip is architectural justification, functional verification, and configurability. This thesis explores verification of the Colt chip at various levels of development including mapping arithmetic computations and DSP algorithms that the Colt architecture was designed to solve. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. CCM configuration verification DSP Virginia Tech Electrical and Computer Engineering A. Lynn Abbott Joseph G. Tront Peter M. Athanas Committee Chair unrestricted http://scholar.lib.vt.edu/theses/available/etd-234115969621901/ " s1997 vau| sm 00| 0|eng d" (VPI) etd-197231939761081 Chien, Kevin Yang-Cheng A Line demarcating Greenwich Village Computer data - 1 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1997 Thesis (MA)--Virginia Polytechnic Institute and State University, 1997-02-07 Includes bibliographical references. The trail of the artifact is an anonymous line on a tourist map of Manhattan. It delimits the boundary, separates the inner and outer, and occupies space. This occupied space juxtaposing the edge of Greenwich Village is an invisible and a undetermined line in the city. Architecture is the result of thinking of object as act, as transformation, and as invention. The project searches, explores, and makes this line present. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. consciousness line conceptual demarcate Virginia Tech Architecture Pia Sarpaneva William Galloway Frank Weiner Committee Chair restricted http://scholar.lib.vt.edu/theses/available/etd-197231939761081/ " s1997 vau| sm 00| 0|eng d" (VPI) etd-243114171971470 Christian, Jason L. From Two Packets to One: Increasing the Performance of Linda-LAN Computer data - 1 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1997 Thesis (MS)--Virginia Polytechnic Institute and State University, 1997-02-03 Includes bibliographical references. Although networked-based computational environments such as Linda-LAN provide parallel processing capability, performance is still a major concern. One critical factor that can hinder the performance of any parallel processing environment is the high cost of interprocess communication. The goal of this project is to increase the performance of C-Linda programs executed in the Linda-LAN environment. With the current two packet message passing scheme, a receiving process listens for a header packet to arrive on a socket connection. Once the header packet has been received, the process then reads the data packet that follows. Reading the data packet may cause the process to block since the data may not have arrived. By modifying the two packet scheme to use only a single packet, the potential for blocking is removed since the header and data packets are guaranteed to arrive at the same time. Hence, the time spent waiting for the data is nullified, thus producing an increase in performance. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. linda-LAN network interprocess communication linda parallel processing Virginia Tech Computer Science Dr. Calvin Ribbens Dr. James D. Arthur Committee Chair Dr. Osman Balci unrestricted http://scholar.lib.vt.edu/theses/available/etd-243114171971470/ " s1996 vau| sm 00| 0|eng d" (VPI) etd-3023162379652351 Clark, Richard L. Jr. Influence of the Interphase on the Mechanical Properties of Nylon 66 Composites Computer data - 1 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1996 Thesis (PHD)--Virginia Polytechnic Institute and State University, 1996-08-01 Includes bibliographical references. The mechanical properties of glass fiber and carbon fiber reinforced nylon 66 were investigated using both microscopic and macroscopic testing techniques. The objective was to determine how different interphase morphologies affect the adhesion and properties such as damping, ultimate stress and strain, and modulus of the composite. This was accomplished using a modified fiber pull-out test on single filament composites, and dynamic mechanical analysis, vibrational adhesion testing, and uni-axial tension testing on bulk composite samples. Additional techniques such as scanning electron microscopy, profilometry, thermogravimetric analysis, differential scanning calorimetry, and water absorption measurements were performed to assist in data interpretation. The specific interphase that forms in both glass reinforced and high modulus carbon fiber reinforced nylon 66 is termed transcrystallinity. Previous work has shown that this region can be altered by the addition of a specific diluent, poly(vinyl pyrrolidone), as either a blend to the matrix or as a fiber sizing. The diluent serves to dampen nucleation on the fiber surface thus causing the interphase to change from transcrystalline in nature to spherulitic. The changes in composite properties that the different interphases produce were examined. Results from the modified fiber pull-out test showed that the interfacial shear strength decreases as the interphase becomes more spherulitic. Scanning electron microscopy revealed a more cohesive fracture surface of the samples having a transcrystalline interphase. Dynamic mechanical analysis showed that the damping behavior of E-glass/nylon 66 composites does not change with PVP sizing, while carbon fiber/nylon 66 composites showed a decrease in damping with the addition of sizing. Vibrational adhesion testing showed similar effects in the loss tangent of both composites versus fiber sizing. In addition, uni-axial tensile testing revealed an increase in the ultimate strength and toughness of both composites. On the other hand, neither the ultimate strain or modulus was a strong function of fiber sizing. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. none Virginia Tech Materials Science and Engineering James P. Wightman Committee Member Ronald G. Kander Committee Chair Brian J. Love Committee Member Thomas C. Ward Committee Member Bryan B. Sauer Committee Member unrestricted http://scholar.lib.vt.edu/theses/available/etd-3023162379652351/ " s1997 vau| sm 00| 0|eng d" (VPI) etd-5502061974360 Colby, Lesley A. The Humoral Immune Response of Elks (Cervus elaphus nelsoni) and Mice to Vaccination with Brucella abortus Strain RB51 Computer data - 1 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1997 Thesis (MS)--Virginia Polytechnic Institute and State University, 1997-02-04 Includes bibliographical references. Vaccine Brucella abortus strain RB51, unlike the wild strain 2308 and another vaccine strain (strain 19) does not induce anti-O-chain antibodies. An efficacious vaccine strain that fails to produce an O-chain and thus a lack of an anti-O-chain humoral response greatly simplifies identification of vaccinated versus field strain infected animals. The three primary objectives of this research were the following: 1) to develop a serological assay to detect anti-RB51 antibodies in vaccinated elk (Cervus elaphus nelsoni), 2) to identify potential antigenic alterations in RB51 after vaccination of elk and BALB/c mice, and 3) to confirm the general stability of RB51. Elk were divided into four groups based upon gender and the route of inoculation (subcutaneous or ballistic) of RB51 bacteria. This study developed a highly reliable ELISA (using a monoclonal anti-bovine IgG 1 antibody and acetone killed whole RB51 bacteria) which can identify RB51-vaccinated elk. Also, isolates recovered from RB51-vaccinated elk were inoculated into female BALB/c mice whose spleens were then cultured. All elk and mice isolates were bacteriologically, biochemically, and serologically evaluated. This study showed that RB51 is a highly stable strain, which does not revert to smooth morphology or initiate synthesis of LPS-O-chain, maintains it biochemical characteristics, does not undergo detectable antigenic variations, and remains attenuated even after successive passages in elk and mice. Overall, this research indicates that RB51 is a vaccine candidate for the prevention of brucellosis in elk. Further studies are needed to determine the protective capabilities of RB51 in elk. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. BALB/c ELISA biobullet western blot brucellosis Virginia Tech Veterinary Medical Sciences G. G. Schurig DVM, PHD Committee Chair S. Ansar Ahmed, BVSc, PHD N. Sriranganathan, BVSc, MVSc, PhD unrestricted http://scholar.lib.vt.edu/theses/available/etd-5502061974360/ " s1997 vau| sm 00| 0|eng d" (VPI) etd-74919282975860 Coley, James A Reconstitution of Place Computer data - 1 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1997 Thesis (MA)--Virginia Polytechnic Institute and State University, 1997-02-05 Includes bibliographical references. By drawing upon the essential characteristics of a locality, an architect may, through reinterpretation, reconstitute a place. This occurs when mundane characteristics of a locality are reformulated in such a manner that their presence becomes significant. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. reconstitution poetic place poetry Virginia Tech Architecture William Brown Committee Chair V. Hunter Pittman Pia Sarpaneva Frank Weiner restricted http://scholar.lib.vt.edu/theses/available/etd-74919282975860/ " s1997 vau| sm 00| 0|eng d" (VPI) etd-32082539751141 Collins, Dennis James An Examination of Driver Performance Under Reduced Visibility Conditions When Using An In-Vehicle Signing Information System (ISIS) Computer data - 1 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1997 Thesis (MS)--Virginia Polytechnic Institute and State University, 1997-04-10 Includes bibliographical references. Recent technological innovations and the need for increased safety on the world's roads have led to the introduction of In- Vehicle Information Systems (IVIS). These systems will provide navigation and advisory information to drivers while they are driving. One aspect of these systems, In-vehicle Signing Information Systems (ISIS), would provide the warning, regulatory, and advisory information that is currently found on road signs. These systems may be of particular benefit when external elements such as rain, snow, or night driving reduce or eliminate the opportunity for drivers to detect road signs. This study attempts to determine what benefits, if any, are realized by drivers using this system. Fifty-eight drivers operated an instrumented Oldsmobile Aurora under eight conditions. The eight conditions consisted of a daylight-clear weather-ISIS condition, a daylight-clear weather-No ISIS condition, a daylight-rain-ISIS condition, a daylight-rain-No ISIS condition, a night-clear weather-ISIS condition, a night-clear weather-No ISIS condition, a night-rain-ISIS condition, and a night-rain-No ISIS condition. Younger drivers (18-30 years old) and older drivers (65 years or older) took part in this study. Three measures of driver performance were collected along with subjective preference data. Each measure was evaluated in order to determine what impact, if any, weather, time of day, age, and ISIS use had on performance. Subjective data was evaluated to determine driver preference and acceptance of the ISIS display. The results indicated that use of the ISIS display led to reduced speeds and greater reaction distances for all drivers. Evidence was found that seems to indicate that older drivers may receive a greater benefit in complex, unfamiliar, or low visibility situations. Evidence was also found that indicates that all drivers may receive a greater benefit at night for the complex or unfamiliar situations. Subjectively, the majority of the drivers indicated that the ISIS display made them more aware of road sign information. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. adverse weather ISIS Driver performance Virginia Tech Industrial and Systems Engineering Thomas A. Dingus Committee Chair Walter W. Wierwille Vicki L. Neale unrestricted http://scholar.lib.vt.edu/theses/available/etd-32082539751141/ " s1997 vau| sm 00| 0|eng d" (VPI) etd-51481373971961 Combs, Michael T. Optimal Analysis of Sulfonamides From Biological Matrices Using Supercritical Fluids Computer data - 1 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1997 Thesis (PHD)--Virginia Polytechnic Institute and State University, 1997-03-11 Includes bibliographical references. The objective of this research was to develop new sample preparation procedures for the isolation of sulfonamides, as well as, to determine the applicability of employing on-line nitrogen selective and mass spectrometric detection methods. The first phase of this research investigated the effect of temperature and pressure on the supercritical fluid extraction (SFE) of sulfonamides from a spiked sand matrix. Temperature effects were either positive or negative with respect to extraction rate and total recovery, depending on the pressure and extraction fluid employed. The second portion of this research compared trifluoromethane (CHF3) and carbon dioxide (CO2) as fluids for the extraction of sulfonamides from spiked non-fat dry milk, beef liver, and egg yolk were found to be more selective using CHF3 than CO2. The polar trifluoromethane improved the extraction efficiency of the polar sulfonamides from the biological matrices and also reduced the amount of co-extractives. The next phase of this research considered the effect of organic modifier and CO2 in the SFE of sulfonamides from chicken liver, beef liver and egg yolk. Methanol, ethanol, acetone, acetonitrile were compared to determine optimum conditions. A SFE method employing 20% acetonitrile modified CO2 yielded quantitative recovery of sulfonamides from chicken liver, but 20% acetone modified CO2 was required to obtain quantitative recovery from beef liver. Either 20% acetone or 20% acetonitrile yielded quantitative recovery from egg yolk. The last phase of this research focused on the evaluation of selective detection methods for sulfonamide analysis. Chemiluminescence nitrogen detection (CLND) parameters were optimized for use with packed column supercritical fluid chromatography (SFC) yielding a minimum detectable quantity (MDQ) of 5 ng of sulfamethazine, on column. Improvements in the detector design decreased the MDQ to 0.5 ng, while, decreasing the column diameter further reduced the MDQ to 125 pg. The second part of this phase evaluated HPLC/Atmospheric pressure chemical ionization (APCI) mass spectrometry for the detection of sulfonamides. Sensitivity in selective ion mode was found to be as low as 50 pg on column for sulfamethazine. Supercritical fluid extracts of sulfonamides spiked at 100æg/kg in chicken liver were found to be readily detected by this method. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. extraction supercritical chicken liver beef liver sulfonamides egg yolk chromatography mass spectrometry SFE CLND atmospheric pressure chemical ionization HPLC/MS SFC Virginia Tech Chemistry Larry L. Taylor Committee Chair Neal Castagnoli, Jr. Harold M. McNair James O. Glanville Mark R. Anderson unrestricted http://scholar.lib.vt.edu/theses/available/etd-51481373971961/ " s1997 vau| sm 00| 0|eng d" (VPI) etd-5115131974430 Coombs, Dana Joseph Design of User-Weight-based Exercise Machines Computer data - 1 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1997 Thesis (MS)--Virginia Polytechnic Institute and State University, 1997-02-07 Includes bibliographical references. This thesis describes the process of designing exercise machines that raise the weight of the user as the primary source of resistance. Most strength training machines use weight stacks or springs as the source of resistance. While such machines are highly evolved and provide an excellent workout, they typically have a number of disadvantages including high cost, and large size and weight. A user weight-based exercise design will reduce the cost, size and weight of the machine. The design process considers some important issues. Parallelogram linkages are implemented to provide non-rotary motion without the disadvantage of linear bearings. The user input is located with respect to the user providing correct relative motion for the exercise. The design also considers proper resistance curves during the design process. Specific examples are given for each step of the design process. These examples include the evolution of ideas and the creation and use of kinematic and automatic tools. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. linkage engineering design kinematics exercise equipment Virginia Tech Mechanical Engineering Charles F. Reinholtz Committee Chair Larry D. Mitchell Committee Member Paul H. Tidwell Committee Member unrestricted http://scholar.lib.vt.edu/theses/available/etd-5115131974430/ " s1997 vau| sm 00| 0|eng d" (VPI) etd-65172149731401 Cotton, Sarah Mitchell Bodies of Knowledge: The Influence of Slaves on the Antebellum Medical Community Computer data - 11 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1997 Thesis (MA)--Virginia Polytechnic Institute and State University, 1997-05-02 Includes bibliographical references. The influence of slaves on the south is well documented in areas such as agriculture, music, diet, religion and language. This thesis extends the list to include medicine. It also suggests that the importance of cultural transfer to America from places other than Europe has been overlooked in the history of medicine. The medical influence of slaves took the form of botanical remedies, many of them with an African origin, and were disseminated through the treatments of slave healers. Slave medical knowledge offered a viable alternative for whites to both nineteenth-century "heroic" practices and to alternative methods, such as homeopathy and Thomsonianism. In addition, the slave's body itself was a vehicle of medical influence. Informed by nineteenth-century beliefs about the differences between whites and blacks, antebellum physicians performed experiments upon slave bodies that they could not and did not perform on whites'. Transfer of slave medical knowledge was facilitated by personal contact between individuals, by the publicity surrounding slaves who were set free for revealing cures, through the services of slave healers, through newspapers and medical journals in which whites wrote of slave treatments and acknowledged the source of the information, and through word of mouth. This study uses the theme of ambivalence to reconcile the conflicting attitudes of southern physicians and slaveowners towards slave medical knowledge. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. none Virginia Tech History Kathleen W. Jones Committee Chair Beverly Bunch-Lyons Crandall Shifflett restricted http://scholar.lib.vt.edu/theses/available/etd-65172149731401/ " s1997 vau| sm 00| 0|eng d" (VPI) etd-4744152149731401 Curtis, Christopher M. "Can These Be The Sons of Their Fathers" The Defense of Slavery in Virginia, 1831-1832 Computer data - 9 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1997 Thesis (MA)--Virginia Polytechnic Institute and State University, 1997-03-28 Includes bibliographical references. This study argues that the Virginia slavery debate of 1831-32 was an occasion when radical transformations in the nature of the proslavery argument occurred and where changing popular perceptions about the role of government can be seen. Since the Revolution, government in Virginia had been based upon the Lockean concept of the inviolable right of private property and of property’s central relationship to government. During the slavery debate, when the initial emancipationist plan, which addressed the slaveholders’ property rights, was dismissed as impractical, a more radical antislavery doctrine was proposed that challenged traditional beliefs concerning property and the function of government. This doctrine was the legal concept of eminent domain, the right of the state to take private property for public purposes without the consent of the owner. Arguing that slavery threatened public safety, emancipationists called on the state government to act within its eminent domain powers to confiscate this harmful species of property. In the climate of increased public fear, brought on by the recent slave insurrection in Southampton County, this particular emancipationist argument subverted the traditional necessary evil justification for slavery. Defenders of slavery became impaled upon the horns of a dilemma. If they continued to acknowledge that slavery was evil, then they risked engendering the expansive government powers that the emancipationists advocated. If slavery could no longer be justified as a necessary evil, then upon what grounds must its defense now rest? In the face of this dilemma, defenders abandoned their traditional apologetic justification and instead advanced the idea of slavery as a “positive good.” System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. proslavery slavery emancipation virginia Virginia Tech History Crandall Shifflett Committee Chair Neil Larry Shumsky Peter Wallenstein unrestricted http://scholar.lib.vt.edu/theses/available/etd-4744152149731401/ " s1997 vau| sm 00| 0|eng d" (VPI) etd-65916251972550 Valero, Carlos Alberto Applications of Qualitative and Quantitative Techniques of Management in Administrative/Academic Decision-Making in Institutions of Higher Education in Virginia. Computer data - 2 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1997 Thesis (PHD)--Virginia Polytechnic Institute and State University, 1997-02-04 Includes bibliographical references. The purpose of this study was to examine the status and extent to which administrators of colleges and universities in the state of Virginia apply qualitative and quantitative techniques of management in planning, directing, reporting, and controlling activities for enhancing their administrative and academic decision-making capability. The study was directed to the top and operative organizational levels in two categories of administrators (nonacademic and academic) to determine the types of managerial techniques used, degrees of familiarity with these techniques, frequency of use, managerial benefits and constraints, and individual and organizational factors involved in using such techniques. The qualitative and quantitative techniques were selected from diverse sources of related literature. The study followed guidelines of exploratory and descriptive research. Data were collected through a questionnaire mailed to 288 administrators of twelve randomly selected colleges and universities in Virginia. The study was limited to institutions granting at least a four-year baccalaureate degree and having a total enrollment of at least 1,000 students. Data were analyzed using descriptive statistics and factorial analysis of variance to describe administrators1 decision-making capability in terms of the extent of utilization of the selected techniques. Based upon a 55 percent response rate, the findings show that administrators have moderate knowledge about the techniques and their extent of use is fairly low. No significant statistical differences in the degree of familiarity and extent of use with various management techniques (qualitative and quantitative) either by category of administrator assignment (nonacademic and academic) and by level or type of administrator (executive and operative) was found. The most reported techniques related to familiarity and extent of use were Brainstorming, Checklists, Benchmarking and Cost-Benefit Analysis. Respondents positively use and perceive the value of qualitative techniques more favorably than the quantitative techniques for decision-making. Results of this study may be of benefit to both practitioners and academicians. Based upon this study1s findings, practical implications are discussed. Limitations and suggestions also are made for future research into this topic. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. none Virginia Tech Education Dr. David Parks Dr. John W. Dickey Dr. Stephen R. Parson Dr. Karl T. Hereford Dr. Don G. Creamer Committee Chair unrestricted http://scholar.lib.vt.edu/theses/available/etd-65916251972550/ " s1997 vau| sm 00| 0|eng d" (VPI) etd-64712549711241 Daller, Melissa L. The Use of Developmental Advising Models By Professional Academic Advisors Computer data - 1 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1997 Thesis (MA)--Virginia Polytechnic Institute and State University, 1997-04-23 Includes bibliographical references. Academic advising has undergone tremendous changes since its origin in higher education. The notion of faculty performing clerical tasks in order to aid students strictly in academics has been challenged. Today, academic advising is considered one of the best vehicles for promoting intellectual, personal, and social development of students. It is a service that links students’ academic and personal worlds and, hence promotes holistic development. However, little is known about professional advisors, specifically to what extent professional advisors use an approach to advising that can be characterized as developmental. The purpose of this study was to observe and identify the behaviors that occur during academic advising sessions between professional academic advisors and students, and compare these behaviors to the models and definitions of developmental advising proposed in the literature. Qualitative research methods, including observations and interviews, were employed. Ten advisors were observed in 35 actual advising sessions in an effort to identify advising behaviors, which were later used to develop and define advising styles. In addition, each advisor was interviewed about his or her philosophy of advising. Results of the study found that the developmental-prescriptive continuum does not accurately reflect actual advising practice. Most advisor’s style reflected a mix of developmental and prescriptive behaviors. However, the characteristics of advising proposed in the literature (e.g.,content, personalization, and decision-making) were useful in identifying and defining new advising styles. Another important finding dealt with personalization. While most advisors stated students are different and have different needs, and some advisors were observed to personalize the advising session, none of the advisors were observed to alter their style in accordance with students’ differences. This suggests there may be a difference between personalization and individualization of advising. Recommendations for practice include assessment of advisors behaviors and philosophies in addition to student perceptions. Also, there is a need to develop new models of advising. The data from this study recommend the development of an advising model that considers the importance of the advisor-advisee relationship that is dynamic and that reflects stages or phases of advising instead of distinct advising styles. The information gathered from this study lends itself to further research about the advising styles used with specialized student populations, suggesting the need for individualization as well as personalization of advising. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. academic advising developmental prescriptive styles behaviors Virginia Tech Student Personnel Services and Counseling Elizabeth G. Creamer Committee Chair Don G. Creamer Delores W. Scott unrestricted http://scholar.lib.vt.edu/theses/available/etd-64712549711241/ " s1997 vau| sm 00| 0|eng d" (VPI) etd-39581323973910 VanDyke, Laura Snively utrient Management Planning on Virginia Livestock Farms: Impacts and Opportunities for Improvement Computer data - 1 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1997 Thesis (MS)--Virginia Polytechnic Institute and State University, 1997-01-31 Includes bibliographical references. This study provides an environmental and economic analysis of the ability to reduce potential nitrogen loadings to water bodies through the implementation of nutrient management plans on livestock farms. Study results indicate that nutrient management plans do result in significant reductions while maintaining or increasing farm income. Nutrient management plans on the four case farms reduced mean nitrogen losses by 23 to 45 percent per acre while increasing net farm income from $395 to $7,249. While reducing excess nitrogen applications with the implementation of nutrient management plans achieved significant reductions in potential nitrogen losses, further reductions may be achieved through farm level planning. After achieving initial reductions through the elimination of excessive nutrient applications, variation in application rates of organic and inorganic fertilizers across soils may become important in achieving further reductions in nitrogen loss. Study results suggest that it may be beneficial to apply higher rates of manure on soils and slopes less susceptible to nitrogen losses in order to reduce applications elsewhere. Increased nutrient losses on such fields may be more than offset by reductions on soils more susceptible to nutrient losses. Linear programming results for the Shenandoah Valley Dairy show that nitrogen losses could be reduced up to 44 percent below pre-plan losses with no impact on farm net economic returns. However, if nitrogen loss restrictions were instituted beyond this level, the impact on farm income increases significantly. After-plan nitrogen losses can reduced up to 52 percent, but farm returns decrease by 56 percent. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. nitrogen nutrient management simulation linear programming economic returns Virginia Tech Agricultural & Applied Economics James Baker James W. Pease Committee Co-Chair Darrell J. Bosch Committee Co-Chair unrestricted http://scholar.lib.vt.edu/theses/available/etd-39581323973910/ " s1996 vau| sm 00| 0|eng d" (VPI) etd-5048131259631631 Vasavada, Yash M. PERFORMANCE EVALUATION OF A FREQUENCY MODULATED SPREAD-SPECTRUM SYSTEM Computer data - 2 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1996 Thesis (MS)--Virginia Polytechnic Institute and State University, 1996-05-01 Includes bibliographical references. Analog frequency modulated (FM) systems offer advantages of reliable speech quality and simplicity, whereas code division multiple access (CDMA) systems promise high capacity, resistance to multipath fading, and simplified frequency planning. In this thesis, we investigate the performance of a wireless local loop (WLL) system that uses the frequency modulation with the CDMA technique. The performance of the FM CDMA system is affected by the choice of the frequency demodulation method. Performance of different state-of-art DSP based FM demodulators is evaluated. Design improvements with threshold extension, pre-deemphasis, and voice companding techniques are explored, and the limitations of the DSP based FM demodulation methods are identifed. The transmitter, the channel, and the receiver of the FM CDMA system are simulated for particular values of FM bandwidth and spread-spectrum processing gain. The capacity supported by the FM CDMA sysem is estimated with different levels of orthogonal as well as non-orthognal multiple access interference. The performance of the FM CDMA system in AWGN, multipath fading, Doppler spread, and nonlinear signal processing effects is predicted. A power control algorithm for the FM CDMA system is proposed, and its effect on the system performance is studied. The capacity of the FM based wireless system may saturate as the system evolves. An adaptive FM CDMA interference cancelation technique and a digital modulation with CDMA are two approaches investigated as ways to improve system capacity. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. none Virginia Tech Electrical and Computer Engineering Dr. Dennis G. Sweeney Dr. Brian D. Woerner Dr. Jeffrey H. Reed Committee Chair unrestricted http://scholar.lib.vt.edu/theses/available/etd-5048131259631631/ " s1997 vau| sm 00| 0|eng d" (VPI) etd-643151739741061 Vasudevan, Lakshmi ANATOMICAL DEVELOPMENTS AND THE ROLE OF CARBOHYDRATE OR MINERAL NUTRIENT DEFICIENCY IN BUD NECROSIS OF ŒRIESLING1 GRAPEVINES (VITIS VINIFERA L.) Computer data - 18 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1997 Thesis (PHD)--Virginia Polytechnic Institute and State University, 1997-02-26 Includes bibliographical references. Bud necrosis (BN) is observed as an abortion and death of one or more primordia of the developing compound winter bud. Anatomical developments during the onset of BN in ŒRiesling1 and ŒChardonnay1 grapevines were characterized. Examination of ultrathin (1micro m) sections of ŒRiesling1 buds under a light microscope revealed a zone of compressed cells immediately beneath the primary bud axis within 60 days after budbreak. Cell rupture occurred in that zone within 90 days after budbreak. Scanning electron microscopy revealed a similar pattern of tissue destruction. Based on the hypothesis that BN was caused by essential substrate deficiency, localized carbohydrate deprivaton was attempted by shading of ŒRiesling1 grapevines and by shoot tip removal. In one experiment, 92% shade was applied for a three-week period at 20, 40, or 60 days after budbreak in one vineyard and at 40 days after budbreak in another vineyard. In another experiment, 92% shade was applied for a 40-day period at 25 or 65 days after budbreak. Shade reduced photosynthetic photon flux (PPF) in the fruit zone of canopies to <2% of ambient PPF. The first experiment did not increase BN. However, the second experiment increased BN in the distal nodes of the shaded vines compared to the control vines. Shoot vigor, measured as shoot diameter and internode length at season1s end, was positively correlated with BN in shaded as well as unshaded vines. The frequency of necrotic buds was greater at nodes 5 through 16 than at nodes 1 to 4 in both shaded and unshaded vines. Levels of total nonstructural carbohydrates (TNC) measured spectrophotometrically, were not significantly affected by shade treatment. Levels of sucrose, glucose, fructose, and starch in bud, leaf, and stem tissues determined by HPLC, were lower in shaded vines at the point of shade removal than in unshaded vines. Therefore, although three-week periods of shade did not affect BN in ŒRiesling1, 40-day periods of shade increased BN in distal nodes. Shoot tip removal increased BN at nodes distal to node 12. Bud tissues of shoot-tipped vines had lower levels of sucrose, glucose, fructose, and starch than did the control vines. Carbohydrate analysis of bud, leaf, and stem tissues indicated that ŒRiesling1 vines (BN-prone) had lower levels of sucrose compared to ŒChardonnay1 vines (BN-insensitive). Role of mineral nutrient deprivation was examined in ŒRiesling1 and ŒChardonnay1 buds and the results indicated that BN is unlikely caused by essential nutrient deficiency. ŒChardonnay1, the BN-insensitive cultivar had greater levels of starch deposits at 50, 60, 70, and 80 days after budbreak than did the BN-susceptible cultivars, ŒRiesling1, Syrah1, and ŒViognier1. Starch deposits in grape buds were negatively correlated with BN incidence. From these experiments it can be concluded that a negative correlation between carbohydrate levels of grape buds and BN incidence exists. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. none Virginia Tech Horticulture S. E. Scheckler E. P. Beers R. E. Byers G. E. Welbaum Committee Co-Chair T. K. Wolf Committee Chair unrestricted http://scholar.lib.vt.edu/theses/available/etd-643151739741061/ " s1997 vau| sm 00| 0|eng d" (VPI) etd-3025191349721321 Veith, Tamie Lynne Netsim: A Java(TM) -Based WWW Simulation Package Computer data - 1 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1997 Thesis (MS)--Virginia Polytechnic Institute and State University, 1997-04-29 Includes bibliographical references. Use of the World Wide Web (WWW) for transfer of information and ideas is increasingly popular. Java, a programming language for the WWW, provides a simple method of distributing platform-independent, executable programs over the WWW. Such programs allow the expansion of WWW-based computational and analytical tools that support and enhance the existing WWW environment. However, a WWW-based, generalized simulation package is not yet available. Current literature motivates development of a general, WWW-based simulation package with maximum user interactivity and cross-platform capabilities. Advantages of such a package are discussed and explored in three potential applications. Main advantages are wide availability, controlled access, efficient maintenance, and increased integration. Disadvantages, such as variable download times, are also discussed. Netsim, a general, WWW-based simulation package written entirely in Java, is developed and demonstrated. Netsim provides complete model creation and modification capabilities along with graphical animation and data output. Netsim uses the event graph paradigm and object-oriented programming. Java, event graphs and object-oriented programming are discussed briefly. The Java random number generator is verified for uniformity and independence. Netsim is compared to SIGMA, a non-Internet simulation package, using a standard M/M/1 queueing model. Comparison issues and results are discussed. Additionally, tested through hand-tracing for coding validity, Netsim performs as theory prescribes. Netsim documentation and user’s manual are included. Netsim allows expandability for complex modeling and integration with other Java-based programs, such as graphing and analysis packages. Current Netsim limitations and potential customization and expansion issues are explored. Future work in WWW-based simulation is suggested System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. internet java modeling netsim programming simulation WWW Virginia Tech Industrial and Systems Engineering J. W. Schmidt John Kobza Committee Co-Chair Pat Koelling Committee Co-Chair unrestricted http://scholar.lib.vt.edu/theses/available/etd-3025191349721321/ " s1997 vau| sm 00| 0|eng d" (VPI) etd-254122839711171 Velasco, Cesar A. Morales Substructure Synthesis Analysis and Hybrid Control Design for Buildings under Seismic Excitation Computer data - 1 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1997 Thesis (PHD)--Virginia Polytechnic Institute and State University, 1997-04-18 Includes bibliographical references. We extend the application of the substructure synthesis method to more complex structures, and establish a design methodology for base isolation and active control in a distributed model of a building under seismic excitation. Our objective is to show that passive and active control complement each other in such an advantageous manner for the case at hand, that simple devices for both types of control are sufficient to achieve excellent response characteristics with very low control forces. The Rayleigh-Ritz based substructure synthesis method proved to be highly successful in analyzing a structure more complex than the ones previously analyzed with it. Comparing the responses of the hybridly controlled building and the conventional fixed building under El Centro excitation, we conclude that the stresses are reduced by 99.6 %, the base displacement is reduced by 91.7 % and the required control force to achieve this is 1.1 % of the building weight. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. substructure synthesis base isolation structural control hybrid control earthquake engineering Virginia Tech Engineering Science and Mechanics H. VanLandingham S. Thangjitham M. P. Singh R. A. Heller L. Meirovitch Committee Chair unrestricted http://scholar.lib.vt.edu/theses/available/etd-254122839711171/ " s1997 vau| sm 00| 0|eng d" (VPI) etd-4524171049761291 Venezia, Jr., James J Vibration Modeling and Experimental Analysis of a Locomotive Cab Computer data - 10 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1997 Thesis (MS)--Virginia Polytechnic Institute and State University, 1997-05-01 Includes bibliographical references. This study evaluates noise and vibrations in a heavy freight locomotive cab, and provides several measures for providing more comfort to the crew. A full-scale production cab and sill structure is used to provide the results. The cab is setup in a controlled laboratory environment in a manner similar to the installation on a locomotive. Field measurements are used to emulate actual vibration input to the cab structure. A 16-channel data acquisition system is used to collect both noise and vibration data on various parts of the cab structure and inside the cab. Upon establishing the baseline for laboratory vibration measurements and correlating them with field data, a design of experiment was conducted to evaluate the vibration contribution of various parts of the cab. This showed that the cab floor and cab roof had the largest vibrations. A series of solutions including stiffening the cab floor and damping the cab roof were investigated. The results showed that although such solutions reduce localized vibrations, the overall effect on reducing cab interior noise is minimal. As a more global solution, the cab was isolated from the sill structure through six elastomeric elements mounted at the base of the cab and at the crash post. The mounts at the base were selected such that they support the static weight of the cab, provide a resonance frequency that is below the excitation range, and offer good lateral and longitudinal stability. Two tube-form elastomeric mounts were placed between the cab structure and the crash posts which attach to the front of the sill structure. The test results showed that the soft-mounted cab had significantly lower noise and vibration than the original cab. The vibration levels were reduced 10 to 100 times at certain locations and frequency ranges. The overall noise level was reduced by approximately 6 dBA. In an attempt to provide an estimate of effectiveness of the mounts with different stiffness values, a simulation model was prepared in Matlab. Although the model did not yield accurate results, it resulted in several recommendations for future research work. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. locomotive cab soft-mounted elastomeric mounts noise-vibration-harshness (NVH) James J. Venezia Jr. Virginia Tech Mechanical Engineering Dr. Larry D. Mitchell Dr. Mehdi Ahmadian Committee Chair Dr. Robert L. West unrestricted http://scholar.lib.vt.edu/theses/available/etd-4524171049761291/ " s1997 vau| sm 00| 0|eng d" (VPI) etd-3156151139751001 Vergara, John Paul C. Sorting by Bounded Permutations Computer data - 2 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1997 Thesis (PHD)--Virginia Polytechnic Institute and State University, 1997-04-08 Includes bibliographical references. Let P be a predicate applicable to permutations. A permutation that satisfies P is called a generator. Given a permutation $pi$, MinSort_P is the problem of finding a shortest sequence of generators that, when composed with $pi$, yields the identity permutation. The length of this sequence is called the P distance of $pi$. Diam_P is the problem of finding the longest such distance for permutations of a given length. MinSort_P and Diam_P, for some choices of P, have applications in the study of genome rearrangements and in the design of interconnection networks. This dissertation considers generators that are swaps, reversals, or block-moves. Distance bounds on these generators are introduced and the corresponding problems are investigated. Reduction results, graph-theoretic models, exact and approximation algorithms, and heuristics for these problems are presented. Experimental results on the heuristics are also provided. When the bound is a function of the length of the permutation, there are several sorting problems such as sorting by block-moves and sorting by reversals whose bounded variants are at least as difficult as the corresponding unbounded problems. For some bounded problems, a strong relationship exists between finding optimal sorting sequences and correcting the relative order of individual pairs of elements. This fact is used in investigating MinSort_P and Diam_P for two particular predicates. A short block-move is a generator that moves an element at most two positions away from its original position. Sorting by short block-moves is solvable in polynomial time for two large classes of permutations: woven bitonic permutations and woven double-strip permutations. For general permutations, a polynomial-time (4/3)-approximation algorithm that computes short block-move distance is devised. The short block-move diameter for length-n permutations is determined. A short swap is a generator that swaps two elements that have at most one element between them. A polynomial-time 2-approximation algorithm for computing short swap distance is devised and a class of permutations where the algorithm computes the exact short swap distance is determined. Bounds for the short swap diameter for length-n permutations are determined. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. none Virginia Tech Computer Science Lenwood S. Heath Committee Chair Donald C. S. Allison Edward L. Green Ezra A. Brown Clifford A. Shaffer unrestricted http://scholar.lib.vt.edu/theses/available/etd-3156151139751001/ " s1997 vau| sm 00| 0|eng d" (VPI) etd-424817300974290 VIGILAR, GREGORIO G. Jr. DETERMINATION OF OPTIMAL STABLE CHANNEL PROFILES Computer data - 19 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1997 Thesis (PHD)--Virginia Polytechnic Institute and State University, 1997-01-28 Includes bibliographical references. A numerical model which determines the geometry of a threshold channel was recently developed. Such a model is an important tool for designing unlined irrigation canals and channelization schemes, and is useful when considering flow regulation. However, its applicability is limited in that its continuously curving boundary does not allow for sediment transport, which is an essential feature of natural rivers and streams. That model has thus been modified to predict the shape and stress distribution of an optimal stable channel; a channel with a flat-bed region over which bedload transport occurs, and curving bank regions composed of particles that are all in a state of incipient motion. It is the combination of this channel geometry and the phenomenon of momentum-diffusion, that allows the present model to simulate the Œstable bank, mobile bed1 condition observed in rivers. The coupled equations of momentum-diffusion and force-balance are solved over the bank region to determine the shape of the channel banks (the bank solution). The width of the channel1s flat-bed region is determined by solving the momentum-diffusion equation over the flat-bed region (the bed solution), using conditions at the junction of the flat-bed and bank regions that ensure match ing of the bed and bank solutions. The model was tested against available experimental and field data, and was found to adequately predict the bank shape and significant dimensions of stable channels. To make the model results more amenable to the practic ing engineer, design equations and plots were developed. These can be used as an alternative solution for stable channel design; relieving the practitioner of the need to run the numerical program. The case of a stable channel that transports both bedload and suspended sediment is briefly discussed. Governing equations and a possible solution scheme for this type of channel are suggested; laying the groundwork for the development of an appropriate numerical model. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. optimal stable threshold mobile momentum-diffusion Virginia Tech Civil Engineering Panayiotis Diplas Committee Chair Sergios Liapis David Kibler Saad Ragab Mark Widdowson unrestricted http://scholar.lib.vt.edu/theses/available/etd-424817300974290/ " s1997 vau| sm 00| 0|eng d" (VPI) etd-13514459731541 Villanueva, Mara̕ Isabel Isabel Martin ̤ The Social Construction of Sexuality: Personal Meanings, Perceptions of Sexual Experience,and Females' Sexuality in Puerto Rico. Computer data - 1 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1997 Thesis (PHD)--Virginia Polytechnic Institute and State University, 1997-05-06 Includes bibliographical references. A qualitative study on a sample of 12 Puerto Rican women was conducted in Puerto Rico. The purpose of this study was to explore the various ways in which sexual meanings are created, changed, and modified as the nature of social discourse and personal experience changes. The two theoretical frameworks that guided the methodology and analysis of the data were social constructionism and feminism. I assumed that sexuality is socially constructed, shaped by social, political, and economic influences, and modified throughout life. Feminist theories assisted in documenting the ways in which females' sexuality in Puerto Rico is shaped by culture and by institutions that disadvantage females and other oppressed groups by silencing their voices. The theories guided the discussion of the contradicting messages about women's sexualities and their experiences, as these women fought, conformed to, and even colluded with their oppression. Analysis of the participants' written and oral narratives produced the overarching theme of sexual meanings/scripts, along with three interrelated sub-themes: sources and nature of sexual scripts, determining experiences, and social discourses of female sexuality. Participants reported three institutional sources of sexual messages: family, religion-culture, and institutions of education. Their determining experiences follow a common thread that weaves a common story line: the life-long struggle with the incongruencies between the social constructions of female sexuality and the realities of these women's sexual experiences. Sexuality is defined as being challenged and modified through the participants' lives. Four social discourses of female sexuality emerged from the analysis of the data: source of guilt and shame, vulnerability and sexual victimization, ambivalence, and empowerment. A theory of ambivalence was developed from the data as a means to understand the participants' process of developing the paradigms for their own sexuality. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. sexuality puerto rico women sexual discourses sexual scripts female sexuality ambivalence Virginia Tech Family and Child Development Michael J. Sporakowski Committee Chair Rosemary Blieszner Mark J. Benson Katherine R. Allen Jay A. Mancini unrestricted http://scholar.lib.vt.edu/theses/available/etd-13514459731541/ " s1996 vau| sm 00| 0|eng d" (VPI) etd-2047101569611961 Villeneuve, Pierre V. A Numerical Study of the Sensitivity of Cloudy-Scene Bidirectional Reflectivity Distribution Functions to Variations in Cloud Parameters Computer data - 2 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1996 Thesis (PHD)--Virginia Polytechnic Institute and State University, 1996-06-28 Includes bibliographical references. The goal of this research has been to characterize the sensitivity of the earth's shortwave bidirectional reflectivity distribution function (BRDF) to variations in cloud parameters. The BRDF is a remote sensing tool used to predict the flux reflected from a given earth scene from a satellite-based measurement of the reflected intensity. The BRDF is necessary in order to account for the anisotropic nature of the shortwave radiation field. A shortwave atmospheric radiation Monte-Carlo ray-trace model has been developed as part of this research to predict the earth-reflected radiation field at the top of the atmosphere. This model was developed while paying special attention to clouds including realistic three-dimensional cloud fields characterized by fundamental physical properties. This model was used to predict the BRDF for various cloud fields where a single cloud parameter was varied as part of the sensitivity analysis. The results show that the shortwave BRDF is very sensitive to changes in cloud vertical thickness and mean cloud size. This sensitivity is also strongly dependent on the direction from which the scene is observed. In a related analysis, a study was done of the error associated with using a BRDF from one scene to retrieve fluxes from a second scene. The model was also used to predict images of cloud fields for comparison with experimental data from the Rutherford Appleton Laboratories satellite-based Along Track Scanning Radiometer (ATSR). Finally the output from the radiation model was integrated with the end-to-end radiative electrothermal model of a practical earth radiation budget instrument. This integrated model was used to predict the instrument response to scanning a realistic partly-cloudy earth scene. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. none Virginia Tech Mechanical Engineering Curtis H. Stern J. Robert Mahan Committee Chair Douglas J. Nelson Elaine P. Scott James B. Campbell unrestricted http://scholar.lib.vt.edu/theses/available/etd-2047101569611961/ " s1998 vau| sm 00| 0|eng d" (VPI) etd-5414132139711101 Unsal, Cem Intelligent Navigation of Autonomous Vehicles in an Automated Highway System: Learning Methods and Interacting Vehicles Approach Computer data - 26 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1998 Thesis (PHD)--Virginia Polytechnic Institute and State University, 1998-07-12 Includes bibliographical references. One of today's most serious social, economical and environmental problems is traffic congestion. In addition to the financial cost of the problem, the number of traffic related injuries and casualties is very high. A recently considered approach to increase safety while reducing congestion and improving driving conditions is Automated Highway Systems (AHS). The AHS will evolve from the present highway system to an intelligent vehicle/highway system that will incorporate communication, vehicle control and traffic management techniques to provide safe, fast and more efficient surface transportation. A key factor in AHS deployment is intelligent vehicle control. While the technology to safely maneuver the vehicles exists, the problem of making intelligent decisions to improve a single vehicle's travel time and safety while optimizing the overall traffic flow is still a stumbling block. We propose an artificial intelligence technique called stochastic learning automata to design an intelligent vehicle path controller. Using the information obtained by on-board sensors and local communication modules, two automata are capable of learning the best possible (lateral and longitudinal) actions to avoid collisions. This learning method is capable of adapting to the automata environment resulting from unmodeled physical environment. Simulations for simultaneous lateral and longitudinal control of an autonomous vehicle provide encouraging results. Although the learning approach taken is capable of providing a safe decision, optimization of the overall traffic flow is also possible by studying the interaction of the vehicles. The design of the adaptive vehicle path planner based on local information is then carried onto the interaction of multiple intelligent vehicles. By analyzing the situations consisting of conflicting desired vehicle paths, we extend our design by additional decision structures. The analysis of the situations and the design of the additional structures are made possible by the study of the interacting reward-penalty mechanisms in individual vehicles. The definition of the physical environment of a vehicle as a series of discrete state transitions associated with a "stationary automata environment" is the key to this analysis and to the design of the intelligent vehicle path controller. This work was supported in part by the Center for Transportation Research and Virginia DOT under Smart Road project, by General Motors ITS Fellowship program, and by Naval Research Laboratory under grant no. N000114-93-1-G022. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. Intelligent Vehicle Control Stochastic Learning Automata Reinforcement Schemes AHS Virginia Tech Electrical and Computer Engineering John S. Bay Committee Chair Joseph A. Ball William T. Baumann Pushkin Kachroo Hugh F. VanLandingham unrestricted http://scholar.lib.vt.edu/theses/available/etd-5414132139711101/ " s1996 vau| sm 00| 0|eng d" (VPI) etd-3132141279612241 Daniels, Harold Lee Interaction of Cognitive Style and Learner Control of Presentation Mode in a Hypermedia Environment Computer data - 1 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1996 Thesis (PHD)--Virginia Polytechnic Institute and State University, 1996-07-18 Includes bibliographical references. Educational hypermedia has been heralded as providing instruction that accommodates learners1 individual differences, allowing them to learn in accordance with their unique needs, desires, and preferences. Advocates of hypermedia point to learner control, multimedia capability, and parallels to theories of human memory as evidence for educational hypermedia1s efficacy. While intuitively appealing, empirical research has not confirmed (or rejected) this assumption. Nor is there compelling evidence to suggest that learners who posses different cognitive styles benefit equally from educational hypermedia environments. This study reports on an examination of cognitive style field dependence/independence and learner control of presentation mode within an educational hypermedia environment. Participants were 122 high school juniors and seniors enrolled in classes whose curricula dealt with the political process. The experimental sites were three high schools located in North Carolina, Virginia, and West Virginia. Learners classified as field dependent and field independent were asked to explore a commercial hypermedia program concerning the presidential primary election process. Participants were randomly assigned to one of two versions of the program, a control group which utilized the commercially designed multimedia presentations and a treatment group that offered the choice of single-channel presentations in addition to the multiple-channel presentations. After interacting with the program participants completed a ten item post test consisting of five recall and five problem-solving questions. Their actions within the hypermedia environment were automatically tracked by the computer. Data analysis consisted of a 3 x 2 ANOVA to examine interaction between field dependency and learner control of presentation mode as measured by the post test. Field dependency was correlated with frequency of multiple-channel selections. A secondary analysis examined main effects and interactions on the recall and problem-solving questions separately utilizing a 3 x 2 ANOVA. Data analysis revealed no correlation between field dependency and frequency of multimedia selections. The study found no significant interaction between field dependency and control (program or learner) of presentation mode as measured by the ten item post test. Separate analysis of the recall and problem-solving questions also revealed no significant interaction. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. multiple-channel learning cognitive style learner control hypermedia Virginia Tech Curriculum and Instruction Norman R. Dodl Committee Chair David M. Moore John K. Burton Susan G. Magliaro John S. Husser unrestricted http://scholar.lib.vt.edu/theses/available/etd-3132141279612241/ " s1997 vau| sm 00| 0|eng d" (VPI) etd-3123162539751141 Dano, Marie-Laure SMA-Induced Deformations In general Unsymmetric Laminates Computer data - 1 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1997 Thesis (PHD)--Virginia Polytechnic Institute and State University, 1997-04-22 Includes bibliographical references. General unsymmetric laminates exhibit large natural curvatures at room temperature. Additionally, inherent to most unsymmetric laminates is the presence of two stable configurations. Multiple configurations and stability issues arise because of the geometric nonlinearities associated with the large curvatures. The laminate can be changed from one stable configuration to the other by a simple snap-through action. This situation offers the opportunity to use shape memory alloys (SMA) attached to the laminate to generate the snap-through forces and change the shape of the laminate on command. Presented is a model which can predict SMA-induced deformations in general unsymmetric laminates and, particularly, the occurrence of the snap through. First, a methodology is developed to predict the deformations of flat general unsymmetric epoxy-matrix composite laminates as they are cooled from their elevated cure temperature. Approximations to the strain fields are used in the expression for the total potential energy, and the Rayleigh-Ritz approach is used to study equilibrium. To further study the laminate deformations, finite-element analyses are performed. Experimental results are presented which confirm the predictions of the developed theory and the finite-element analyses regarding the existence of multiple solutions and the magnitude of the deformations. Results are compared with those of several other investigators. Next, the deformation behavior of general unsymmetric laminates subjected to applied forces is studied. The principle of virtual work is used to derive the equilibrium equations relating the laminate deformations to the applied forces. By solving the equilibrium equations as a function of the force level, relations between the laminate deformations and the applied force are derived, and the force level at which the laminate changes shape is determined. Finally, an existing SMA constitutive model is implemented into the developed theory to predict the deformations of simple structures to SMA-induced forces. Experiments on a narrow aluminium plate with an externally attached SMA actuator are conducted. The experimental results show good agreement with the predictions from the developed theory. Next, the deformation behavior of general unsymmetric laminates subjected to SMA actuators is predicted using the developed theory. Experiments using SMA actuators to generate the snap through of unsymmetric laminates are conducted. Good correlation with the developed theory is obtained. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. shape control modeling of smart structures instability snap through Virginia Tech Engineering Science and Mechanics M. W. Hyer Committee Chair O. H. Griffin, Jr. E. R. Johnson F. Lalande D. H. Morris restricted http://scholar.lib.vt.edu/theses/available/etd-3123162539751141/ " s1996 vau| sm 00| 0|eng d" (VPI) etd-556181169641921 Daniels, Jean Elizabeth Lucas Ethics Education In Marriage and Family Therapy Graduate Programs Computer data - 1 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1996 Thesis (PHD)--Virginia Polytechnic Institute and State University, 1996-06-21 Includes bibliographical references. Mental health professionals place value on education in the hopeful expectation that ethics instruction will provide the knowledge and awareness required to empower therapists to make ethical clinical decisions. This study examined the current status of ethics education in accredited and non accredited marriage and family therapy graduate programs in the United States and Canada. Surveys were sent to ethics instructors in 123 graduate programs, 72 of which have full or provisional accreditation by the AAMFT Commission on Accreditation for Marriage and Family Therapy Education. A total of 65 surveys were returned, resulting in an overall response rate of 53%. Information was gathered using a modified version of a survey designed by Vanek (1990) that examined eight areas of ethics training: 1) professional and educational characteristics of the instructor, 2) structure of ethics education, 3) instructional methods, 4) goals for ethics education, 5) specific content areas, 6) evaluation indices, 7) instructional materials, and 8) rationale for ethics education. Particular attention was placed on ethical content areas that are unique to a systemic approach to therapy. The future direction of ethics instruction was examined to determine whether instructors would significantly alter ethics education in the future. A series of paired t tests for within-group comparisons was used to determine if significant differences existed between the current and desired emphasis placed on 16 educational goals and 34 content areas. With the exception of four goals, there were statistically significant differences (p<.05) between the current and future emphasis placed on all other goals by ethics instructors. There were also statistically significant differences (p<.05) between the current and future emphasis placed on 22 of the 34 content areas by ethics instructors. These results indicated that the majority of ethics instructors place emphasis on these goals and content areas, but acknowledge a desire to place greater emphasis on them in the future. A series of t tests for independent groups determined that there were no significant differences (p<.05) between accredited and non accredited programs in the degree of emphasis currently placed on any of the specified goals or content areas. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. Ethics marriage and family therapy training education Virginia Tech Family and Child Development Dr. Howard Protinsky Committee Chair Dr. Lee Baruth Dr. Joseph Maxwell Dr. Laurie Shea Dr. Michael Sporakowski unrestricted http://scholar.lib.vt.edu/theses/available/etd-556181169641921/ " s1997 vau| sm 00| 0|eng d" (VPI) etd-342482139711101 Danis, Michelle A. The Effects of Multiple Listing on Bid-Ask Spreads for Equity Options Computer data - 5 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1997 Thesis (MA)--Virginia Polytechnic Institute and State University, 1997-04-14 Includes bibliographical references. The purpose of this thesis was to test the hypothesis that multiple-listing of equity options leads to lower bid-ask spreads because of increased competition. This competition can come in two forms, actual or potential, both of which are theorized to have the same effect on spreads. A model of the determinants of the bid-ask spread was formulated. Separate tests were conducted on 1985 and on 1992 CBOE data. The first test arose from the fact that in 1985, only a certain number of options were multiple-listed, or eligible to be multiple-listed. Spreads for multiple-listed options were conjectured to be below spreads for single-listed options across low levels of volume, and equal to single-listed option spreads at higher levels of volume. The evidence for this was mixed based on several regressions with different functional forms. The second test arose from the fact that in 1992, because of an SEC rule change, all options were eligible to be multiple-listed but still only a few were. Spreads for multiple-listed options were conjectured to be equal to spreads for single-listed options because the single-listed options had the potential to become multiple-listed. Again, the evidence for this was mixed. It appears that the actual and potential competitive effects from multiple-listing had yet to come to fruition as of 1992. Further testing revealed that, on an option-by-option basis, spreads generally rose from 1985 to 1992. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. equity options bid-ask spread competition Virginia Tech Economics (Arts & Sciences) Nancy A. Wentzler Committee Chair William R. Porter Brian k. Reid unrestricted http://scholar.lib.vt.edu/theses/available/etd-342482139711101/ " s1997 vau| sm 00| 0|eng d" (VPI) etd-1913943975930 Deang, Jennifer Marie A Study of Inhomogeneities and Anisotrophies In Superconductors via Ginzburg-Landau Type models Computer data - 1 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1997 Thesis (PHD)--Virginia Polytechnic Institute and State University, 1997-03-14 Includes bibliographical references. Superconductivity continues to be of great theoretical and practical interest and remains a challenging area of scientific inquiry. Most superconductors of practical utility are of type-II, i.e., they allow the penetration of magnetic fields in the form of tubes of flux that are referred to as ``vortices.'' Motion of these vortices due to, e.g., applied currents, induce a loss of perfect conductivity. Knowing how vortices move and arrange themselves in lattice structures, how their movement is suppressed by pinning mechanisms, and how their movement is affected by thermal fluctuations is critical to understanding how to maintain resistanceless current flow. We study a variety of Ginzburg-Landau type models for superconductivity that can account for inhomogeneous and anisotropy materials, grain boundaries, and thermal fluctuations. We develop robust, accurate, and efficient numerical codes and apply them to numerous studies of how vortex motions are affected by the various mechanisms mentioned above. We also examine some analytical aspects of type-II superconductors under the influence of thermal fluctuations. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. superconductivity numerical analysis Virginia Tech Mathematics Max D. Gunzburger Committee Chair John A. Burns Eugene M. Cliff Terry L. Herdman Janet S. Peterson unrestricted http://scholar.lib.vt.edu/theses/available/etd-1913943975930/ " s1997 vau| sm 00| 0|eng d" (VPI) etd-402515359721531 DeLorenzo, Michael NUCARS Modeling of a Freight Locomotive with Steerable Trucks Computer data - 1 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1997 Thesis (MS)--Virginia Polytechnic Institute and State University, 1997-05-20 Includes bibliographical references. The rail dynamics modeling package NUCARS has been used extensively to model freight cars. We have found that it can also be used effectively to model freight locomotives. This thesis discusses the development of a NUCARS model to represent a six-axle freight locomotive equipped with steerable trucks. This includes separating it into a set of individual bodies, representing the suspension components as inter-body connections, and validation of the computer model. This model is then used to conduct a study of the impact on tangent track stability and curving performance of varying suspension parameters. It is found that the presence of damping in the system improves hunting stability, while increasing wheel conicity is harmful to stability and varying the flexicoiling stiffness has little effect. In curving, the clearances between the axles and truck frame are very important. Limiting these clearances in the steerable truck causes it to curve similar to a conventional straight locomotive truck and increases both the track force ratios and angles of attack. Increasing the wheel conicity increases an axle's tendency to align with the track and improves the locomotive's curving performance. The lateral stiffness of the inter-axle links and inter-motor links has little effect on the curving of the locomotive. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. NUCARS locomotive steerable trucks bogies parametric Virginia Tech Mechanical Engineering Mehdi Ahmadian Committee Chair Harry H. Robertshaw Norman S. Eiss unrestricted http://scholar.lib.vt.edu/theses/available/etd-402515359721531/ " s1997 vau| sm 00| 0|eng d" (VPI) etd-2025212339731121 Demaree, Heath Allan Analysis of Quantitative Electroencephalographic and Cardiovascular Responses to Stress Amoung Low- and High-Hostiles Computer data - 1 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1997 Thesis (PHD)--Virginia Polytechnic Institute and State University, 1997-04-16 Includes bibliographical references. This experiment was primarily designed to identify higher cortical correlates of cardiovascular arousal. Low- and high-hostile, right-handed, undergraduate men were identified using the Cook Medley Hostility Scale (CMHS). All participants (N = 30) completed the cold pressor paradigm. Cardiovascular (heart rate, systolic blood pressure, and diastolic blood pressure) and electroencephalographic (beta magnitude) data were collected before and after the stressor. As predicted, high-hostiles showed greater increases of heart rate and systolic blood pressure to the stressor relative to low-hostiles. The primary findings of this research include significantly greater beta magnitude recorded by the T3, relative to F7, electrode among low-hostiles. This may suggest that low-hostiles experience left-frontal disinhibition of left-temporal regions, thereby strengthening cardiovascular regulation during the cold-pressor stress. In addition, irrespective of condition, high-hostiles evidenced significantly greater beta magnitude at regions corresponding to the F7 and F8 electrodes. This perhaps suggests that high-hostiles have a relative inability to increase their rostral modulation of posterior systems related to cardiovascular reactivity/regulation. Low- and high-hostiles did not, however, evidence reliable differences in their ability to monitor cardiovascular arousal to the cold-pressor stress. Findings are discussed in terms of a systems approach, and pertinent future research is recommended. This research did not support the prominent neuropsychological theories of cardiovascular regulation proposed by Heilman et al. (1993) and Tucker and Williamson (1984). Rather, the results may suggest that right- and left-cerebral mechanisms may be primarily responsible for sympathetic and parasympathetic cardiovascular arousal, respectively. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. aggression cerebral laterality arousal cerebral asymmetry cardiovascular disease heart rate blood pressure Virginia Tech Psychology David W. Harrison, Ph.D. Committee Chair Robin P. Cooper, Ph.D. Richard M. Eisler, Ph.D. Robert Lickliter, Ph.D. Thomas H. Ollendick, Ph.D. unrestricted http://scholar.lib.vt.edu/theses/available/etd-2025212339731121/ " s1997 vau| sm 00| 0|eng d" (VPI) etd-3331171059721601 Denbow, Cynthia Jones Membrane Domain of Plant 3-Hydroxy-3-Methylglutaryl Coenzyme A Reductase: Targeting, Topology, and Function Computer data - 1 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1997 Thesis (PHD)--Virginia Polytechnic Institute and State University, 1997-05-06 Includes bibliographical references. The rate limiting step in isoprenoid biosynthesis is catalyzed by 3-hydroxy-3-methylglutaryl CoA reductase (HMGR, EC 1.1.1.34). In plants, HMGR is encoded by small gene families whose members are differentially expressed. In tomato, hmg2 was previously isolated and sequenced. We report the isolation and sequence analysis of a clone (pCD4) encompassing exon I of tomato hmg1 which encodes the putative membrane domain. Sequence comparisons of plant HMGR proteins reveal two hydrophobic stretches within the amino terminus which are highly conserved among species. Using in vitro transcription and translation systems, the membrane domain structure of two tomato HMGR isoforms, HMG1 and HMG2, were analyzed. Results from these experiments reveal that tomato HMGRs are targeted to microsomal membranes in a cotranslational fashion that does not involve cleavage of an N-terminal targeting peptide. Membrane topography of HMGR was revealed by protease protection studies, indicating that both tomato HMGRs span the membrane two times such that both the C- and N-termini are located within the cytosol. HMG2 but not HMG1 was glycosylated in the in vitro system. Deletion of the hmg1 5£ untranslated regions and sequences encoding the first six highly charged amino acids resulted in inefficient translation in vitro. However, targeting to microsomes was unchanged. HMG1 membrane domain was tagged with a FLAG epitope to facilitate in vivo studies. Agrobacterium-mediated transformation was used to introduce the tagged hmg1 gene into two Nicotiana tabacum cell lines, BY-2 and KY-14. The slow growth kinetics of KY-14 prevented effective recovery of transformed lines, however, Northern analyses of BY-2 showed that the hmg1 transgene was expressed. Comparisons of BY-2 and KY-14 revealed differences in defense responses to elicitor treatment. BY-2 cells showed minimal defense capabilities, whereas KY-14 cells were rapidly induced as indicated by increased HMGR enzyme activity and browning of the cells. HMGR enzyme activity was decreased in both KY-14 and BY-2 cells following sterol treatment, but the reduction was more pronounced in KY-14 cells. Thus transgenic BY-2 cells may be useful in future in vivo immunolocalization studies, but analyses of HMGR transcriptional regulation and regulated degradation will require use of the more responsive KY-14 cells.. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. tomato HMGR protein targeting membrane topology protein degradation epitope-tag transgenic cells Virginia Tech Plant Pathology Dr. Carole L. Cramer Committee Chair Dr. Elizabeth A. Grabau Dr. Kriton K. Hatzios Dr. David N. Radin Dr. Sue A. Tolin unrestricted http://scholar.lib.vt.edu/theses/available/etd-3331171059721601/ " s1996 vau| sm 00| 0|eng d" (VPI) etd-18409759651581 DeVaux, David R. A Tutorial on Authorware Computer data - 1 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1996 Thesis (MS)--Virginia Polytechnic Institute and State University, 1996-04-25 Includes bibliographical references. Authorware is an icon-based multimedia authoring tool which allows the rapid development of complex interactive multimedia projects, particularly courseware and kiosk applications, for both the Macintosh and Microsoft Windows operating systems. This project consists of three main elements: interactive courseware, written in Authorware, which teaches the student basic concepts involved in Authorware programming, and demonstrates the function of each of the icons used to program in Authorware; a tutorial through which students are given the opportunity to use Authorware to incorporate various media elements, including written audio, graphics, video, and text, into their own interactive courseware; and various course materials, including a statement of objectives, study questions, and quiz questions. These materials were developed for use in the Virginia Tech Computer Science course CS4984 (Multimedia, Hypertext, and Information Access) as part of the unit on System and Application Construction. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. authorware authoring multimedia CBT Virginia Tech Computer Science Dr. Edward Fox Committee Chair Dr. John Carroll Dr. Mary Beth Rosson unrestricted http://scholar.lib.vt.edu/theses/available/etd-18409759651581/ " s1997 vau| sm 00| 0|eng d" (VPI) etd-34521672975650 Dodd, Jennifer Peters Chemical Identification and Organoleptic Evaluation of Iodine and Iodinated Disinfection By-Products Associated with Treated Spacecraft Drinking Water Computer data - 1 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1997 Thesis (MS)--Virginia Polytechnic Institute and State University, 1997-02-11 Includes bibliographical references. Aboard the International Space Station, potable water will likely be produced from recycled wastewater. The National Aeronautic and Space Administration (NASA) plans to use iodine as a disinfectant, and, consequently, the formation of iodinated disinfection by-products (IDBPs) requires investigation. Objectives of this research were to determine possible precursors of IDBPs, identify IDBPs formed, and apply flavor profile analysis (FPA) as a tool to evaluate water qaulity. Experiments were performed by separately reacting iodine with each of the following organic compounds: methanol, ethanol, 1-propanol, 2-propanol, 1-methoxy-2-propanol, acetone, and formaldehyde. NASA previously identified all of these compounds in wastewater sources under consideration for recycling into potable water. Experiments were performed at pH 5.5 and 8, iodine concentrations of 10 and 50 mg/L, and organic concentrations of 5 and 50 mg/L. Gas chromatography/mass spectrometry was used to identify and monitor the concentrations of organic species. Spectrophotometry was used to monitor the iodine concentration. Acetone was the only compound identified as an IDBP precursor and it reacted to produce iodoacetone and iodoform. Concentrations of iodoform from 0.34 mg/L to 8.637 mg/L were produced at conditions that included each pH level, iodine concentration, and acetone concentration. The greatest iodoform concentration was produced at pH 8 from 50 mg/L of iodine and acetone. FPA indicated that the odor threshold concentration (OTC) of iodoform was 1.5 ug/L, and the OTC of iodine was 500 ug/L. Both iodine and iodoform have medicinal odors, making it difficult to distinguish each compound when present in a mixture. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. disinfection by-product iodine iodoform flavor profile analysis Virginia Tech Civil Engineering Andrea Dietrich Committee Chair Robert Hoehn Daniel Gallagher unrestricted http://scholar.lib.vt.edu/theses/available/etd-34521672975650/ " s1997 vau| sm 00| 0|eng d" (VPI) etd-120142139711101 Domokos-Bays, Becky L. The Role Of The Citizen's Clearinghouse For Hazardous Wastes As An Agent Of AdultEducation In The Environmental Justice Movement From 1981-1985 Computer data - 2 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1997 Thesis (PHD)--Virginia Polytechnic Institute and State University, 1997-03-12 Includes bibliographical references. This historical study examined the educational dimensions of the Citizen’s Clearinghouse for Hazardous Wastes from 1981-1995. Its role as an agent of adult education in the grassroots movement for environmental justice was demonstrated by tracing the movement from the toxic waste disaster at Love Canal, New York and focusing on the role of Lois Gibbs as a leader in the movement. The conceptual framework for the study was built upon interdisciplinary work in the fields of adult education, sociology, and educational history. The study examined the mission, belief systems, processes and strategies of learning and information dissemination by the Clearinghouse during three periods: 1981-1986, during which the organization was formed and began to develop a mission and belief system; the 1987-1991 period when CCHW experienced enormous growth and began to exert its power nationally with campaigns such as the McToxics Campaign. It was also during this period that CCHW began the process of working toward a unified grassroots environmental justice movement; and the period from 1992-1995 which marked the beginning of CCHW’s second decade of existence and in which CCHW conducted an in-depth organizational assessment. Organizing and technical assistance were found to be the primary vehicles of learning. Publications and site visits were powerful dissemination mechanisms used to assist citizens in their struggles against corporations and government authorities. Secondly, citizens who remained active in the environmental justice movement often took on broader roles such as organizing regional citizen groups. The study found that women composed nearly eighty percent of the leaders in the movement. Reasons for involvement varied, but most women became involved initially out of fear for theirs or a loved one’s health. Conclusions drawn indicate that learning occurred through everyday experiences and empowered citizens to take direct action in their communities. Secondly CCHW emerged as a powerful national political force due to its ability to maintain its mission of continuously listening and meeting the needs of its grassroots constituents. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. social movements CCHW adult education Virginia Tech Adult and Continuing Education Harold Stubblefield Committee Chair Marcie Boucouvalas Tom Hunt Ron McKeen Suzanne K. Murrmann unrestricted http://scholar.lib.vt.edu/theses/available/etd-120142139711101/ " s1997 vau| sm 00| 0|eng d" (VPI) etd-4019122049721391 Dotson, Paul Randolph Jr. Sisson's Kingdom: Loyalty Divisions in Floyd County, Virginia, 1861-1865 Computer data - 6 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1997 Thesis (MA)--Virginia Polytechnic Institute and State University, 1997-05-01 Includes bibliographical references. "Sisson's Kingdom" uses a community study paradigm to offer an interpretation of the Confederate homefront collapse of Floyd County, Virginia. The study focuses primarily on residents' conflicting loyalty choices during the war, and attempts to explain the myriad of ways that their discord operated to remove Floyd County as a positive portion of the Confederate homefront. The study separates the "active Confederate disloyalty" of Floyd County's Unionist inhabitants from the "passive Confederate disloyalty" of relatives or friends of local Confederate deserters. It then explores the conflicting loyalties of the county's pro-Confederates, Unionists, and passive disloyalists, seeking to understand better the wide variety of loyalty choices available to residents as well as the consequences of their choices. To determine some of the significant factors contributing to the Floyd County community's response to the Confederacy and Civil War, this thesis documents the various ways residents' reactions took shape. Chapter One examines the roots of these decisions, exploring briefly Floyd County's entrance into Virginia's market economy during the 1850s and its residents' conflicting choices during Virginia's secession crisis. In the aftermath of secession, many Floyd residents embraced their new Confederate government and enlisted by the hundreds in its military units. The decision by some county soldiers to desert their units and return to Floyd caused loyalty conflicts between their supporters and the county's pro-Confederates. This conflict, and the effects of deserters living in the Floyd community, are both explored in Chapter Two. Floyd's Unionist population and its loyal Confederate residents clashed violently throughout much of the war, hastening the disintegration of the Floyd homefront. Their discord is examined in Chapter Three. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. appalachia desertion floyd county civil war unionism Virginia Tech History Dr. Crandall A. Shifflett Committee Chair Dr. James I. Robertson, Jr. Dr. Peter Wallenstein unrestricted http://scholar.lib.vt.edu/theses/available/etd-4019122049721391/ " s1997 vau| sm 00| 0|eng d" (VPI) etd-487142639761151 Usita, Paula M. Immigrant Mothers--American Daughters: Context and Meaning of Relationships Computer data - 2 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1997 Thesis (PHD)--Virginia Polytechnic Institute and State University, 1997-04-22 Includes bibliographical references. Life course and gender theorists emphasize the importance of contextual factors on human development and family life, including social structural positions, assignment of meaning to events, and cultural beliefs and practices. In addition, life course theorists punctuate the relevance of event timing on individual and familial growth and they seek to understand adaptive life patterns. Family scholars and gerontologists espouse the use of life course and gender theories to examine ethnic minorities' familial experiences. The present research examined relationships between immigrant post WWII mothers in mid and late life and adult daughters. Five contextual factors were examined: (1) perceptions of minority group status; (2) beliefs of having power, privilege, and prestige; (3) ethnic community involvement; (4) language and communication practices; and (5) expectations of women's relationships within families. In addition, the researcher considered the timing of mothers' immigration on relationship patterns. Twenty-two mothers and daughters participated in individual semi-structured interviews in which they discussed the associations among the contextual factors and challenging, fulfilling, and neutral relationship pathways. Thematic analysis of the mothers' and daughters' interview data and analysis of the investigator's research journal revealed that dimensions of communication, transitions and turning points, culture, and contact underscore relationship pathway. The findings from the present study contribute to theoretical perspectives, such as life course and gender theory, by illustrating the juxtaposition among factors such as generational position, culture, and gender. The implications of the research include the utility of using gender and life course perspectives jointly, the importance of considering how policies have direct and lingering affects on people's lives, the significance of social geography in ethnic minorities' lives, the need to attend to generational positions within immigrant families, and the usefulness of the research findings for support group settings and for counselors working with immigrant and ethnic minority group members. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. gender gerontology immigrant minority relationship Virginia Tech Family and Child Development Katherine R. Allen Rosemary Blieszner Committee Chair Jay A. Mancini Ann Kilkelly Victoria R. Fu unrestricted http://scholar.lib.vt.edu/theses/available/etd-487142639761151/ " s1997 vau| sm 00| 0|eng d" (VPI) etd-5943202339731121 Drayer, Thomas Hudson A Design Methodology for Creating Programmable Logic-based Real-time Image Processing Hardware Computer data - 1 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1997 Thesis (PHD)--Virginia Polytechnic Institute and State University, 1997-01-24 Includes bibliographical references. A new design methodology that produces hardware solutions for performing real-time image processing is presented here. This design methodology provides significant advantages over traditional hardware design approaches by translating real-time image processing tasks into the gate-level resources of programmable logic-based hardware architectures. The use of programmable logic allows high-performance solutions to be realized with very efficient utilization of available logic and interconnection resources. These implementations provide comparable performance at a lower cost than other available programmable logic-based hardware architectures. This new design methodology is based on two components: a programmable logic-based destination hardware architecture and a suite of development system software. The destination hardware architecture is a Custom Computing Machine (CCM) that contains multiple Field Programmable Gate Array (FPGA) chips. FPGA chips provide gate-level programmability for the hardware architecture. Sophisticated software development tools, called the TRAVERSE development system software, are created to overcome the significant amount of time and expertise required to manually utilize this gate-level programmability. The new hardware architecture and development system software combine to establish a unique design methodology. There are several distinct contributions provided by this dissertation. The new flexible MORRPH hardware architecture provides a more efficient solution for creating real-time image processing computing machines than current commercial hardware architectures. The TRAVERSE development system software is the first integrated development system specifically for creating real-time image processing designs with multiple FPGA-based CCMs. New standards and design conventions are defined specifically for creating solutions to low-level image processing tasks, using the MORRPH architecture for verification. The circuit partitioning and global routing programs of the TRAVERSE development system software enable automated translation of image processing designs into the resources of multiple FPGA chips in the hardware architecture. In a broad sense, the individual contributions of this dissertation combine to create a new design methodology that will change the way hardware solutions are created for real-time image processing in the future. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. real-time image processing FPGA-based computing design methodology reconfigurable computing MORRPH TRAVERSE Virginia Tech Electrical and Computer Engineering Joseph G. Tront Committee Chair Richard W. Conners Committee Co-Chair A. Lynn Abbott D. Earl Kline Charles E. Nunnally unrestricted http://scholar.lib.vt.edu/theses/available/etd-5943202339731121/ " s1997 vau| sm 00| 0|eng d" (VPI) etd-3447141249711311 Dulaney, Ronald E. Jr. Library Computer data - 1 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1997 Thesis (MArch)--Virginia Polytechnic Institute and State University, 1997-05-01 Includes bibliographical references. This study began with the desire to design a public town library of the future and became a search for an inkling of what is essential to Architecture. It is murky and full of contradictions. It asks more than it proposes, and the traces of its windings are better ordered through collage than logical synthesis. This study is neither a thesis nor a synthesis. When drawing out the measure of this study it may be beneficial to state what it attempts to place at the perimeter. Architecture is not a product of society, civilization, or economy. Architecture is not democratic, and it cannot be brought forward in the public realm. Architecture is not a private affair. Architecture is not space, and it is not building. This study does attempt to hold that Architecture is founded in speech and gesture which originate in culture. As 'constructions' (construings), Architecture and the book share with the body the potential for utterance. The library is the coincidence of Architecture, the book, and the body. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. architecture building library book body Virginia Tech Architecture Steve Thompson Committee Chair Heinrich Schnoedt Frank Weiner unrestricted http://scholar.lib.vt.edu/theses/available/etd-3447141249711311/ " s1997 vau| sm 00| 0|eng d" (VPI) etd-524414252972830 Dwyer, John L. Adult Education in Civil War Richmond January 1861- April 1865 Computer data - 1 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1997 Thesis (PHD)--Virginia Polytechnic Institute and State University, 1997-03-19 Includes bibliographical references. This study examines adult education in Civil War Richmond from January 1861 to April 1865. Drawing on a range of sources (including newspapers, magazines, letters and diaries, reports, school catalogs, and published and unpublished personal narratives), it explores the types and availability of adult education activities and the impact that these activities had on influencing the mind, emotions, and attitudes of the residents. The analysis reveals that for four years, Richmond, the Capital of the Confederacy, endured severe hardships and tragedies of war: overcrowdedness, disease, wounded and sick soldiers, food shortages, high inflationary rates, crime, sanitation deficiencies, and weakened socio-educational institutions. Despite these deplorable conditions, the examination reveals that educative systems of organizations, groups, and individuals offered the opportunity and means for personal development and growth. The study presents and tracks the educational activities of organizations like churches, amusement centers, colleges, evening schools, military, and voluntary groups to determine the type and theme of their activities for educational purposes, such as personal development, leisure, and recreation. The study examines and tracks such activities as higher education, industrial training, religious education, college-preparatory education, military training, informal education, and educational leisure and recreation, such as reading and listening to and singing music. The study concludes that wartime conditions had minimal affect on the type and availability of adult education. Based on the number and types of educational activities and participants engaged in such activities, the study concludes that adult education had influenced and contributed to the lives of the majority of Richmonders, including the thousands of soldiers convalescing in the city's hospitals. Whatever the educative system, the study finds that the people of Richmond, under tremendous stress and despondency improved themselves individually and collectively. Thus, Civil War Richmond's adult education experience is about educative systems that gave people knowledge, comfort, and hope under extreme deprivation and deplorable conditions. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. richmond adult education civil war Virginia Tech Adult Education Harold W. Stubblefield Committee Chair Alan W. Beck Thomas C. Hunt Ronald L. McKeen Albert K. Wiswell restricted http://scholar.lib.vt.edu/theses/available/etd-524414252972830/ " s1997 vau| sm 00| 0|eng d" (VPI) etd-36171339701021 Teaster, Pamela B WHEN THE STATE TAKES OVER A LIFE: THE PUBLIC GUARDIAN AS PUBLIC ADMINISTRATOR Computer data - 1 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1997 Thesis (PHD)--Virginia Polytechnic Institute and State University, 1997-02-17 Includes bibliographical references. Public guardians are individuals appointed by the state to care for the interests of incapacitated citizens. The nature and quality of their care is examined at sites in Maryland, Delaware, Tennessee, and Virginia. In the first three states public guardianship programs have been running for at least ten years; in Virginia two pilot projects are currently underway. All sites use different service delivery models. In addition to studying case file notes, public guardians, program supervisors, and wards were observed and interviewed with regard to their background, their views on public guardianship, accountability and effectiveness, and services provided. The aim of this study is to contribute to a better qualitative understanding of how well state public guardian programs intersect intimately with individuals for whom no other responsible decision maker exists. The study concludes with recommendations regarding the roles of the public guardian in improving wards' quality of life through substitute decision making and in enhancing democratic governance to give voice to wards through their own participation in decision making and relationships with their public guardian. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. autonomy public administration guardianship democratic governance Virginia Tech Public Administration and Public Affairs Larkin S. Dudley William J. McAuley Doris T. Zallen Gary L. Wamsley unrestricted http://scholar.lib.vt.edu/theses/available/etd-36171339701021/ " s1996 vau| sm 00| 0|eng d" (VPI) etd-283092199612941 Eaglesham, Susan L. Online Support Groups: Extending Communities of Concern Computer data - 1 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1996 Thesis (PHD)--Virginia Polytechnic Institute and State University, 1996-09-18 Includes bibliographical references. Using survey data from 75 participants in computer self-help groups, variables were identified which theoretically indicate that computer self- help groups function similarly to face-to-face self-help groups.This exploratory research provided demographic information which allows users of computer self-help groups to be more clearly described. The findings of this study indicated that computer group users perceived similar benefits of use to people in traditional self-help groups. Study participants also perceived certain benefits from computer group use not found in traditional face-to-face groups. Among these were the convenience of use, anonymity, and the benefits of writing as a way to connect to others. The findings indicated that computer groups provided a unique context in which new beliefs and ideas about problems can be constructed. The findings were interpreted to indicate that there are certain risks involved in computer group use of which mental health professionals and potential users need to be cognizant. Finally, several areas for possible future study are discussed. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. therapy computers self-help groups Virginia Tech Family and Child Devleopment: Joyce A. Arditti Committee Chair Scott W. Johnson Howard O. Protinsky Michael J. Sporakowski Claire Cole Vaught unrestricted http://scholar.lib.vt.edu/theses/available/etd-283092199612941/ " s1996 vau| sm 00| 0|eng d" (VPI) etd-23521427119653610 Ellis, Roger L. Ballistic Impact Resistance of Graphite Epoxy Composites With Shape Memory Alloy and Extended Chain Polyethylene Spectra Hybrid Components Computer data - 1 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1996 Thesis (MS)--Virginia Polytechnic Institute and State University, 1996-12-09 Includes bibliographical references. Graphite epoxy composites lack effective mechanisms for absorbing local impact energy often resulting in penetration and a structural strength reduction. The effect of adding small amounts of two types of high strain hybrid components on the impact resis tance of graphite epoxy composites subjected to projectiles traveling at ballistic velocities (greater than 900 ft/sec) has been studied. The hybrid components tested include superelastic shape memory alloy (SMA), a material having an unusually high stra in to failure (15 - 20%), and a high performance extended chain polyethylene (ECPE) known as Spectra™, a polymer fiber traditionally used in soft and hard body armor applications. A 1.2% volume fraction superelastic SMA fiber layer was embedded on the specimens front, middle, and backface to determine the best location for a hybrid component in the graphite composite. From visual observation and energy absorption values, it was c oncluded that the backface is the most suitable location for a high strain hybrid component. Unlike the front and middle locations, the hybrid component is not restricted from straining by surrounding graphite material. However, no significant increases in energy absorption were found when two perpendicular SMA layers and an SMA-aramid weave configuration were tested on the backface. In all cases, the embedded SMA fibers were pulled through the graphite without straining to their full potential. It is believed that this is due to high strain rate effects coupled with a strain mismatch between the tough SMA and the brittle epoxy resin. However, a significant increase in energy absorption was found by adding ECPE layers to the backface of the composite . With only a 12% increase in total composite mass, a 99% increase in energy absorption was observed. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. ballistic impact hybrid composites graphite composites SMA spectra Virginia Tech Mechanical Engineering Dr. Frederic Lalande Committee Co-Chair Dr. Craig A. Rogers Committee Co-Chair Dr. Victor Giurgiutiu unrestricted http://scholar.lib.vt.edu/theses/available/etd-23521427119653610/ " s1997 vau| sm 00| 0|eng d" (VPI) etd-1719959711591 Ely, Paul T. Internal Damping Rates of Construction Cranes Computer data - 1 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1997 Thesis (MS)--Virginia Polytechnic Institute and State University, 1997-05-27 Includes bibliographical references. The conveyance of payloads by construction cranes generates pendulations of the payload. This research provides a critical design parameter for the development of a device that aids in reduction of these pendulations. Previous research developed a tuned mass damping system, that effectively attenuated the energy of a pendulating payload. In order to be effective the internal damping rate of the tuned mass damper must be at least twice that of the system to be damped. Prototypes of a tuned mass damping system have achieved damping rates between 6 and 12 %, making cranes with damping rates below 3% attractive. This research indicates that the internal damping rate of construction cranes is on the order of one percent, suggesting that a tuned mass damping system could be retrofitted to today's construction cranes. This thesis is an investigation of the internal damping rates of construction cranes. Three hydraulic and two lattice boom cranes were tested. The motion of pendulating payloads was modeled after a simple pendulum. The internal damping rate was calculated using logarithmic decrement technique. Light to medium duty cranes were tested with loads similar to those used in duty cycle operations. Damping tests were performed both perpendicular and parallel to the mast of the crane. Values were calculated from data extracted from videos of a payload oscillating over a measurement scale. A FMC Link Belt 25-ton hydraulic crane was tested at 6.4 % of capacity and displayed damping rates between 0.25 and 0.6 %. A 50-ton FMC Link Belt was tested at 10 % of capacity and had damping rates of 0.18 % for both tests. The third hydraulic crane was a 60-ton P&H T-600XL. The test parallel to the mast was performed at 6 % of capacity having a damping rate of 0.22 %. The test-performed perpendicular to the mast was at 3.5 % of capacity with a damping rate of 0.65 %. Two lattice boom cranes with capacities of 70 and 100 tons were tested. The 70-ton LIMA 778c£s damping rates were 0.06 and 1.3 percent. This test was performed at 15 % of capacity. The 100-ton Link Belt LS318 was tested at 6.8 % of capacity and had damping rates between 0.07 and 0.08 percent. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. none Virginia Tech Civil Engineering Dr. Yvan J. Beliveau Committee Chair Dr. Thomas Brandon Dr. James Lutz unrestricted http://scholar.lib.vt.edu/theses/available/etd-1719959711591/ " s1997 vau| sm 00| 0|eng d" (VPI) etd-182122439741131 Thayne, Tim R Solution-Focused Leadership: The Development and Evaluation of a Marriage and Family Therapy-Based Leadership Training Program Computer data - 1 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1997 Thesis (PHD)--Virginia Polytechnic Institute and State University, 1997-04-02 Includes bibliographical references. This research project utilized concepts and methods from the field of marriage and family therapy, to help leaders from business organizations develop greater relationship competency. A training workshop was designed and then evaluated to improve the quality of the training process, and to answer the following question: what, if any, effect did the workshop have on the participants1 relationship competencies in their work and/or family roles? The workshop participants were 12 people from small to medium sized business organizations who held leadership positions in their companies. The training model consisted of an initial three-day session, followed by a two-month interim period where the participants were given individual coaching, concluded by a two-day follow-up session. Several qualitative methods were used for obtaining data including the use of focus groups, in-depth interviews, and case notes. Formative evaluation processes provided information critical to the program1s improvement. Summative evaluation results indicate that the training was effective in helping individuals increase their relationship competency in the following four areas: 1) increased awareness, 2) greater relationship orientation, 3) new relationship-oriented behaviors, and 4) perceived outcomes. Participants reported having greater awareness of their own cognitive and emotional processes, as well as greater empathy for the experiences of others. Participants1 attitudes became more relationally oriented and were followed by new behaviors that promoted closer family relationships and collaborative work relationships. Participants credited the training with positive relational outcomes such as greater trust, more intimacy, and better communication in selected relationships. Other outcomes, specific to the experience of particular individuals, were also attributed to the training experience. The results provide preliminary evidence that MFT processes may be effective in helping leaders develop interpersonal or relationship competencies in a workshop setting. This study adds to the collection of research where family therapy models have been successfully utilized in diverse human systems contexts. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. leadership development program evaluation interpersonal competency marriage and family therapy solution-focused therapy Virginia Tech Family and Child Development Howard Protinsky Committee Chair Kusum Singh Committee Member Harold A. Kurstedt, Jr. Committee Member Joseph W. Maxwell, Jr. Committee Member Michael J. Sporakowski Committee Member unrestricted http://scholar.lib.vt.edu/theses/available/etd-182122439741131/ " s1996 vau| sm 00| 0|eng d" (VPI) etd-222102139711101 Ergen, Feyza F. Effects of Interface Format, Feedback Style, and System Lag on the Usability of Hand-Held Internet Controllers Computer data - 1 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1996 Thesis (MS)--Virginia Polytechnic Institute and State University, 1996-12-17 Includes bibliographical references. The increasing popularity of the World Wide Web (WWW) has created a new market: Web access through television to accommodate those who either cannot afford existing hardware or are intimidated by computers. Current efforts to combine the WWW and television have targeted potential novice users. One of the approaches for creating a WWW browsing system that is both simple to use and inexpensive is the utilization of the existing cable system to provide Web access through television. Some unique characteristics of this browsing system are fast access to the Web, the use of nine buttons on a universal remote control, and an index structure for reaching Web sites. Since browsing the Web through television is relatively new, many interface issues need to be examined. The purpose of this research was to investigate potential user interface designs for this WWW browser and to evaluate the usability of the nine-button interface. Sixteen volunteers participated in the experiment and were asked to navigate to specific Web sites with two interface formats, five different system lag times (0.2, 0.7, 1.3, 2.0, and 3.0 seconds), and three feedback styles (active feedback, passive feedback and no feedback). Participants were prescreened for their experience with computers and browsing the Web. The experiment was conducted in a living room setting to simulate real life situations and participants were given a total of 42 tasks to complete throughout the experiment. Each task consisted of navigating through the tree structure with either one of the two interface formats until reaching a designated Web site. The number of errors committed and task completion times were recorded. In addition, participants were asked to rate the WWW browser system after each task as well as after the entire experiment. Participants preferred the 0.2 second system lag and the active feedback style. Overall, they committed fewer errors and took less time to complete tasks with the tabbing interface than with the one-to-one mapping interface. Experienced participants committed more errors than did the inexperienced ones. Increase of system lag time was determined to have a greater adverse effect on the tabbing interface than on the one-to-one mapping interface. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. user-interface design human-computer interaction system response time feedback tree-menu structures internet Virginia Tech Industrial and Systems Engineering Robert J. Beaton Committee Chair John Deighan Willard Farley unrestricted http://scholar.lib.vt.edu/theses/available/etd-222102139711101/ " s1997 vau| sm 00| 0|eng d" (VPI) etd-1624102249741411 Theaux, Heather M Discrimination of Linguistic and Prosodic Information In Infant-Directed Speech by Six-Month-Olds Computer data - 3 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1997 Thesis (MS)--Virginia Polytechnic Institute and State University, 1997-05-08 Includes bibliographical references. The purpose of the present study was to tease apart the paralinguistic from the linguistic aspects of infants' perception of infant-directed (ID) speech. Several studies have shown that infants beginning at a few days after birth discriminate native from nonnative speech and can discriminate specific contours (rising, falling, rising-falling) in ID speech. Some studies have also indicated that infants at 4.5 months of age prefer their own name over other names but at 6 months of age, fail to prefer a sentence with their own name embedded in it. Using a discrimination procedure, the current study investigated whether 6-month-old infants could detect a change in contour and/or a change in words when listening to ID utterances. Results indicated that 6-month-old infants detected both a contour and a word change. From these results, it is argued that as has been shown in other exper- iments, infants are extremely sensitive to subtle changes in speech. Furthermore, ID speech appears to facilitate infants' ability to discriminate small changes in ID speech (both linguistic and paralinguistic). It is suggested that future studies investigate more discrete changes in speech samples and a replication of this research with adult-directed (AD) speech. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. word discrimination pitch contours infant directed speech Virginia Tech Psychology Robin Panneton Cooper Committee Chair Martha Ann Bell Helen J. Crawford unrestricted http://scholar.lib.vt.edu/theses/available/etd-1624102249741411/ " s1996 vau| sm 00| 0|eng d" (VPI) etd-38431826109623300 Escobar, Jose Alejandro stress and fatigue analysis of svi-tested camshaft lobes Computer data - 1 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1996 Thesis (MS)--Virginia Polytechnic Institute and State University, 1996-11-08 Includes bibliographical references. Nondestructive evaluation techniques were employed to fully characterize three 2.3L camshafts tested in an engine simulator for an equivalent of 100,000 miles. Optical microscopy, acoustic microscopy (SAM), and profilometry were used to characterize wear and fatigue, crack depth, and surface roughness, respectively. Results show cracking to occur mainly in the opening ramp of the most abusively ground cam lobes. No clear evidence was found for subsurface cracking at depths as great as 200 mm from the lobe£s surface. Profilometry results show no evidence of any major tribological effect due to the sliding friction of the follower. Fractography studies show a difference between fracture surfaces among the cracks examined; straight cracks exhibit features resembling fatigue propagation, while fracture surfaces from pitted cracks show a more brittle behavior. Small grinding cracks (approximately 300 mm in length) were found in the opening ramps of the most abusively ground lobes prior to testing. Knoop and Nanoindenter microhardness indicate a near-surface rehardening for the most abusively ground lobe (confirmed by metallography), and temper burn for the remaining lobes. X-ray residual stress results made in the opening ramp of the tested lobes show evidence of residual stress relaxation. X-ray line width data as a function of depth does not correlate with residual stress. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. camshaft lobes grinding residual stress fatigue life prediction rolling contact stress fatigue engine testing fracture surfaces thermal damage Virginia Tech Materials Science and Engineering Robert W. Hendricks Committee Chair Ronald W. Landgraf Stephen L. Kampe William T. Reynolds unrestricted http://scholar.lib.vt.edu/theses/available/etd-38431826109623300/ " s1997 vau| sm 00| 0|eng d" (VPI) etd-1826102339731121 Evans, Gwynnen Stokes programs on paper: an examination of virginia's service delivery area jobh training partnership act title II-A job training plans Computer data - 4 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1997 Thesis (MS)--Virginia Polytechnic Institute and State University, 1997-04-17 Includes bibliographical references. A key purpose of federal job training policy is to ensure that the workforce has the skills necessary to obtain and retain gainful employment. The purpose of this study was to describe and compare key elements of Virginia's fourteen service delivery area (SDA) plans in order to determine how they would deliver programs to achieve the stated purpose of JTPA Title II-A, which targets disadvantaged adults. In addition, the plans were evaluated as to their potential to guide successful program implementation. The plans were reviewed to describe and analyze who is trained, how they are trained, and what objectives the plans establish. The plans were ranked as to their fulfillment of eight criteria drawn from JTPA studies on successful program strategies and from education program planning literature. Though the plans provided basic descriptions of SDA efforts to train disadvantaged adults, they did not reflect full use of successful strategies or education program planning techniques, especially in the areas of linking training to the local labor market and using overall evaluation. The SDAs did not use the plans to distinguish their local level activities, opting most often to meet minimal compliance with plan guidelines as to the information provided. The individual being trained is underrepresented in most of the plans. A few plans did meet many of the criteria and demonstrated how these strategies and planning tools can be reflected at this early stage of program implementation. The plan preparation guidelines themselves were found to be a factor in the limitations of the plans. Changes in policy requiring plans to better detail their programs could enhance their effectiveness as planning tools. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. JTPA job training policy implementation Virginia Tech Adult Learning Albert K. Wiswell Committee Chair Marilyn V. Lichtman Harold W. Stubblefield unrestricted http://scholar.lib.vt.edu/theses/available/etd-1826102339731121/ " s1997 vau| sm 00| 0|eng d" (VPI) etd-583512259711521 Faison, Inga L. The Effect of Ozone on Diesel Soot Precursors Computer data - 1 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1997 Thesis (MS)--Virginia Polytechnic Institute and State University, 1997-04-23 Includes bibliographical references. A joint experimental and numerical project has been initiated at Virginia Tech to study the effect of ozone on diesel soot precursors. This thesis is the first stage of the numerical part of the project, and contains a study of the effect of the different ozone levels on diesel soot precursors. This numerical study is executed via the use of two computer programs, Senkin, and PSR. An idealistic model of the diesel engine was used in both analyses. The numerical studies were done at three different engine speeds, 1500, 2000, 2500 RPM and eight different levels of ozone. Studies were performed with ozone introduced with the intake air and with the fuel. Eleven product species, which include dominant soot precursors such as acetylene (C2H2) and the propargyl radical (C3H3), were examined and evaluated during this experiment. After analyzing both simulations, the PSR predictions were not useful since it omits the existence of temperature and species gradients. The PSR analysis was used as a preliminary model to get an overall idea of combustion pollutant formation and predicted the exit soot precursor concentrations were unaffected by any ozone addition. However, the Senkin analysis predicted the ozone injection did have the potential to reduce the formation of soot precursors. The Senkin analysis predicted more realistic results and therefore it is believed to yield the correct conclusion. However, it was suggested that an additional program, such as KIVA3, be utilized to predict a more practical view of the chemical kinetic behavior of ozone and its effect on the diesel engine. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. soot precursors diesel engine combustion ozone Virginia Tech Mechanical Engineering Dr. Balakrishnan Ganeshan Committee Chair Dr. Uri Vandsburger Dr. Alan A. Kornhauser unrestricted http://scholar.lib.vt.edu/theses/available/etd-583512259711521/ " s1997 vau| sm 00| 0|eng d" (VPI) etd-10623859701581 Flora, Jonathan P. The Effects of Temperature On The Durability Of Resistance Of Soybean To Soybean Mosaic Virus Computer data - 1 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1997 Thesis (MS)--Virginia Polytechnic Institute and State University, 1997-05-08 Includes bibliographical references. The objectives of this study were to determine the effects the temperature sensitivity of alleles of Rsv1 in soybean (Glycine max (L.) Merr.). Soybean cultivars carrying alleles of Rsv1 were exposed to several heat treatments designed to induce heat shock protein production prior to inoculation with soybean mosaic virus (SMV). The heat treatment methods were similar to those employed in the research with N gene-tobacco mosaic virus studies. The soybean cultivars used were Lee 69, York, Kwanggyo, Ogden and PI96983, carrying the Rsv, Rsv1-y, Rsv1-k, Rsv1-t, and Rsv1 allles of Rsv1, respectively, and were selected to provide a range of reactions to selected SMV pathotype groups. For example Rsv1-y and Rsv1-k give a necrotic response to SMV G4 and SMV G6, respectively, while both are resistant to SMV G1. To determine the durability of resistance under heat shock conditions, the symptoms were observed for changes in the phenotype of the resistance response. Immunological techniques were employed to determine the vascular movement and localization of the viral antigen in the plant. Heat treatments used were found to induce HSP but to have no effect on the resistance phenotype. A detached leaf assay was used to test the same Rsv1 alleles at constant high temperatures. Primary trifoliolate leaflets were removed and inoculated, then placed into a continuously lighted incubator at 20 C or 30 C. Leaf immunoprint assays were used to determine the localization of the viral antigen. The visible symptoms for necrotic lesions and veins were observed for necrotic phenotype-pathotype combinations but mosaic symptoms were not observed on detached leaves, as expected for inoculated leaves. The detached leaf assay confirmed that no change from the expected resistance response of the Rsv1 alleles occurred at 30 C. A breakdown of resistance to SMV at high temperature had been reported in soybean by Tu and Buzzell (1987). The resistance gene in which the high temperature breakdown occurred has been determined to be in Rsv3. Using cultivars and breeding lines carrying Rsv3 in a similar experiment was attempted in growth chambers. Preliminary results suggest that Rsv3 is temperature sensitive. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. soybean mosaic virus resistance heat shock Virginia Tech Plant Pathology Dr. Sue A. Tolin Committee Chair Dr. Glenn R. Buss Dr. Herman Warren restricted http://scholar.lib.vt.edu/theses/available/etd-10623859701581/ " s1998 vau| sm 00| 0|eng d" (VPI) etd-105513359611541 Fowler, Christian Synthesis Fundamentals Seminar: Testing the Instructional Project Development and Management (IPDM) Model Computer data - 1 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1998 Thesis (MA)--Virginia Polytechnic Institute and State University, 1998-08-12 Includes bibliographical references. This paper presents the development of an instructional unit that tested an instructional development model. The model was based on the Instructional Project Development and Management (IPDM) model designed by Castelle Gentry. A short student seminar was developed using the stages and techniques proposed by Gentry. The subject of the seminar was electronic music synthesizer programming. An evaluation of the seminar concludes that it is an efficient and complete model for developing instructional units. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. gentry instructional design musical synthesizer IPDM Virginia Tech Education Glen Holmes Committee Chair John Husser John Burton unrestricted http://scholar.lib.vt.edu/theses/available/etd-105513359611541/ " s1996 vau| sm 00| 0|eng d" (VPI) etd-5134151959631701 Fowler, Leslie Paige Application of the Filtered-X LMS Algorithm for Disturbance Rejection in Time-Periodic Systems Computer data - 1 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1996 Thesis (MS)--Virginia Polytechnic Institute and State University, 1996-05-03 Includes bibliographical references. Extensive disturbance rejection methods have been established for time-invariant systems. However, the development of these techniques has not focused on application to time-periodic systems in particular until recently. The filtered-X LMS algorithm is regarded as the best disturbance rejection technique for aperiodic systems by many, as has been proven in the acoustics industry for rejecting unwanted noise. Since this is essentially a feedforward approach, we might expect its performance to be good with respect to time-periodic systems in which the disturbance frequency is already known. The work presented in this thesis is an investigation of the performance of the filtered-X LMS algorithm for disturbance rejection in time-periodic systems. Two cases are examined: a generalized linear, time-periodic system and the helicopter rotor blade in forward flight. Results for the generalized system show that the filtered-X LMS algorithm does converge for time-periodic disturbance inputs and can produce very small errors. For the helicopter rotor blade system the algorithm is shown to produce very small errors, with a 96%, or 14 dB, reduction in error from the open-loop system. The filtered-X LMS disturbance rejection technique is shown to provide a successful means of rejecting time-periodic disturbances for time-periodic systems. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. adaptive control filtered-x LMS time-periodic disturbance rejection helicopter rotor blade Virginia Tech Mechanical Engineering Harry H. Robertshaw Committee Chair William R. Saunders Harley H. Cudney unrestricted http://scholar.lib.vt.edu/theses/available/etd-5134151959631701/ " s1997 vau| sm 00| 0|eng d" (VPI) etd-2517151449731331 Freeman, Philip M. Residing Computer data - 1 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1997 Thesis (MA)--Virginia Polytechnic Institute and State University, 1997-05-06 Includes bibliographical references. Architecture possesses the potential to elevate one's intellectual and visceral perceptions from unconscious passings to informed events. The quest for creating events involves an intermediary which promotes the transition from a casual involvement to an active engagement. This intermediary role is that of the experience. By imposing a presence, or creating a sense of place, architecture awakens the mind and stirs the soul. Doing this, the architecture is raised to a higher order, revealing a significance that is true, as something more, not as something else. The making of events through the experience fulfills the aspirations of architecture to unearth the events that dwell in the interaction between place and occasion. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. entering transitioning gathering withdrawing Virginia Tech Architecture Pia Sarpaneva Committee Chair Michael O'Brien Frank Weiner restricted http://scholar.lib.vt.edu/theses/available/etd-2517151449731331/ " s1997 vau| sm 00| 0|eng d" (VPI) etd-204516459731541 Gagnon, Heather Elizabeth Scandalous Beginnings: Witch Trials to Witch City Computer data - 1 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1997 Thesis (MA)--Virginia Polytechnic Institute and State University, 1997-05-21 Includes bibliographical references. On June 10, 1692, Bridget Bishop was hung as a witch in the community of Salem Village of the Massachusetts colony. Bishop was the first of twenty that died, all of whom professed their innocence. By the end of the madness, more than two hundred persons stood accused of witchcraft. They attempted to prove their innocence or they falsely admitted guilt in order to save their own lives. Citizens did not discuss the episode for many years after the trials were ended. The whole episode was an embarrassing blemish on the history of the state, and there was little atonement for the unjust hangings of those who had proclaimed their innocence. Three hundred years later, Salem, Massachusetts is very different. The image of the witch on a broomstick has been commercialized, and the city has become known as the “Witch City.” The city makes over $25 million a year in tourism and is one of the largest tourist attractions in all of New England. This change raises some very important questions, such as how did this change occur? Why did it occur? Is Salem unique? How did perceptions change over time, and why? This thesis attempts to answer these questions by examining a variety of sources. This thesis strives to explain how a tiny New England town that experienced the tragic phenomenon of the witch trials and hangings, evolved into the present-day Witch City. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. witch trials witches massachusetts cities salem Virginia Tech History Ronald J. Nurse Committee Chair Arthur R. Ekirch Daniel B. Thorp unrestricted http://scholar.lib.vt.edu/theses/available/etd-204516459731541/ " s1999 vau| sm 00| 0|eng d" (VPI) etd-120199-091346 Jones, Mary Ellen Politically Corrected Science: The Early Negotiation of U.S. Agricultural Biotechnology Policy Computer data - 1 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1999 Thesis (PHD)--Virginia Polytechnic Institute and State University, 1999-11-19 Includes bibliographical references. This social history of science policy development emphasizes the impact on the agricultural community of federal policies regarding release of recombinant DNA (rDNA) organisms into the environment. The history also demonstrates that the U.S. Coordinated Framework for Biotechnology Regulation (1986) is based principally in political criteria, not solidly based in science as its proponents claimed. The power struggle among policy negotiators with incompatible belief systems resulted in a political correction of biotechnology. I also demonstrate that episodes in the rDNA controversy occur in repetitive and periodic patterns. <p> During the 1980s, the first rDNA microbial pesticide, Ice-Minus, struggled through a policy gauntlet of federal agency approval processes, a Congressional hearing, and many legal actions before it was finally released into the environment. At the height of the controversy (1984-1986), the Reagan Administration would admit no new laws or regulations to slow the development of technologies or hinder American international competitiveness. At the same time, Jeremy Rifkin, a radical activist representing a green world view, used the controversy to agitate for social and economic reform. Meanwhile, a group of Congressional aides who called themselves the “Cloneheads” used the debate to fight for more public participation in the science policy-making process. <p> Conflicting perspectives regarding biotechnology originated, not in level of understanding of the science involved, but in personal perspectives that were outwardly expressed as political group affiliations. The direction of federal biotechnology policy was influenced most successfully by politically best-positioned individuals (what I call a “hierarchy effect”) who based decisions on how biotechnology harmonized with their pre-existing beliefs. The success of their actions also depended on timing. <p> Historical events during the rDNA controversy followed the same periodic pattern--gestation, threshold, crisis/conflict, and quasi-quiescence--through two consecutive eras--the Containment Era (1970s) and the Release Era (1980s). These periods are modeled after Fletcher’s stages through which ethical issues evolve (1990). However, an agricultural perspective on the debate reveals that such stages also occur in finer detail on repeating, overlapping, and multi-level scales. Knowledge of this periodicity may be useful in predicting features of future episodes of the rDNA controversy <p> System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. Cloneheads periodicity of technological controversy Reagan Administration Jeremy Rifkin rDNA world view and science policy preferences genetic engineering recombinant DNA in agriculture science and politics Virginia Tech Science & Technology Studies Richard M. Burian Committee Member Doris T. Zallen Committee Chair Sue A. Tolin Committee Member Richard F. Hirsh Committee Member Cornelia B. Flora Committee Member restricted http://scholar.lib.vt.edu/theses/available/etd-120199-091346/ " s1997 vau| sm 00| 0|eng d" (VPI) etd-374116272974850 Gaines, David N. Studies on Conura torvina (Hymenoptera: Chalcididae) Reproduction and biology in Relation to Hosts in Brassica Crops. Computer data - 1 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1997 Thesis (PHD)--Virginia Polytechnic Institute and State University, 1997-01-24 Includes bibliographical references. Conura torvina (Cresson) (Hymenoptera: Chalcididae) is a solitary pupal endoparasite of numerous insect species. In Brassica crops it acts as a parasite of Plutella xylostella (L.) (Lepidoptera: Plutellidae) and was found as a hyperparasite of Cotesia rubecula (Marshall) (Hymenoptera: Braconidae) and several other parasitoid species. Cotesia rubecula was introduced into Virginia in 1987 as a biological control agent for Pieris rapae (L.) (Lepidoptera: Pieridae), and because C. torvina was thought to have eliminated this population of C. rubecula, studies of C. torvina£s reproductive biology and behavior were initiated. A study using plants laden with "trap hosts" to detect C. torvina activity in the spring indicated no activity until late June, but proved trap host sampling to be an efficient and effective method of monitoring C. torvina activity. Studies of C. torvina£s ability to reproduce in C. rubecula pupae of different ages indicated that C. torvina can successfully parasitize pupae at all stages of development, but was most successful in young to middle aged pupae. Studies of C. torvina£s host species preference indicated the larger host species such as P. xylostella were preferred. Equal numbers of P. xylostella and C. rubecula were parasitized, but a greater proportion of fertile eggs were laid in P. xylostella. Smaller host species were often ignored. Host dissection studies indicated that caged C. torvina were inefficient at host finding and oviposition. Superparasitism was common, but declined as the females gained oviposition experience. Experienced C. torvina produced an average of 8.25 progenies per day for a period of 12 days when provided with 13 P. xylostella hosts each day. Conura torvina produced up to 14 progenies a day when provided 3 26 hosts. Dissection of C. torvina ovaries indicated three ovarioles per ovary with a mean of 9.2 and maximum of 15 mature eggs per female. Host dissection indicated that a mean of 18 and maximum of 30 eggs could be laid per day. New eggs were produced as oviposition occurred. Significantly larger eggs were laid in P. xylostella than in C. rubecula, and significantly more eggs were laid in C. rubecula than in P. xylostella. From these data and data from earlier studies I concluded that C. torvina has a poor reproductive ability and its impact as a hyperparasite is limited to the summer months. This makes C. torvina an unlikely cause of C. rubecula£s disappearance. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. cotesia orobenae cotesia rubecula pieris rapae plutella xylostella development time hyperparasite ovaries ovarioles ovulation oviposition superparasitism seasonality trap plants trap hosts Virginia Tech Entomology Dr. L. T. Kok Committee Chair Dr. R. L. Pienkowski Dr. D. G. Pfeiffer Dr. R. D. Fell Dr. B. D. Opell restricted http://scholar.lib.vt.edu/theses/available/etd-374116272974850/ " s1998 vau| sm 00| 0|eng d" (VPI) etd-1454132679612381 Gardner, Tara Conti Delipidation Treatments for Large-Scale Protein Purification Processing Computer data - 1 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1998 Thesis (PHD)--Virginia Polytechnic Institute and State University, 1998-08-12 Includes bibliographical references. Triglycerides are the majority lipid component of most biochemical mixtures and are virtually water insoluble. Lipid removal is desired prior to protein purification processing to decrease nonspecific fouling of downstream chromatographic matrices. Transgenic pig milk was used as a model system to study delipidation from therapeutic protein sources. The majority of triglycerides was extracted from stable lipid micelles and removed with a method that can be incorporated in downstream protein purification processing without denaturing the target protein. An efficient delipidation treatment used TNBP, a non-polar solvent, to extract lipid micelles and then phase transfer milk lipids into a TNBP-swelled dextran particulate. A batch incubation of a whey/TNBP mixture with pre-swollen Sephadex LH-20 or hydroxyalkoxypropyl dextran (HAPD) beads at 4 C for 24 hours removed 67 + 2 % (0.645 mg triglycerides/ml Sephadex LH-20) and 71 o + 1 % (0.628 mg triglycerides/ml HAPD) of the triglycerides present in the skimmed transgenic whey, respectively. Fully swollen beads removed 20% more triglycerides than beads which were wetted but not swollen in TNBP, indicating that a larger phase volume and internal adsorption of the lipids onto the Sephadex matrix dominates over surface adsorption. Polyclonal ELISAs indicated that 89 + 6% of the recombinant human Protein C was still present in the transgenic whey after this delipidation treatment, indicating this treatment did not denature or harm the target protein. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. delipidation lipid removal protein purification transgenic milk sephadex TNBP Virginia Tech Chemical Engineering William H. Velander Committee Chair Richey M. Davis William L. Conger unrestricted http://scholar.lib.vt.edu/theses/available/etd-1454132679612381/ " s1997 vau| sm 00| 0|eng d" (VPI) etd-5742153049751491 Giunta, Anthony A. Aircraft Multidisciplinary Design Optimization using Design of Experiments Theory and Response Surface Modeling Methods Computer data - 1 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1997 Thesis (PHD)--Virginia Polytechnic Institute and State University, 1997-05-01 Includes bibliographical references. Design engineers often employ numerical optimization techniques to assist in the evaluation and comparison of new aircraft configurations. While the use of numerical optimization methods is largely successful, the presence of numerical noise in realistic engineering optimization problems often inhibits the use of many gradient-based optimization techniques. Numerical noise causes inaccurate gradient calculations which in turn slows or prevents convergence during optimization. The problems created by numerical noise are particularly acute in aircraft design applications where a single aerodynamic or structural analysis of a realistic aircraft configuration may require tens of CPU hours on a supercomputer. The computational expense of the analyses coupled with the convergence difficulties created by numerical noise are significant obstacles to performing aircraft multidisciplinary design optimization. To address these issues, a procedure has been developed to create two types of noise-free mathematical models for use in aircraft optimization studies. These two methods use elements of statistical analysis and the overall procedure for using the methods is made computationally affordable by the application of parallel computing techniques. The first modeling method, which has been the primary focus of this work, employs classical statistical techniques in response surface modeling and least squares surface fitting to yield polynomial approximation models. The second method, in which only a preliminary investigation has been performed, uses Bayesian statistics and an adaptation of the Kriging process in Geostatistics to create exponential function-based interpolating models. The particular application of this research involves modeling the subsonic and supersonic aerodynamic performance of high-speed civil transport (HSCT) aircraft configurations. The aerodynamic models created using the two methods outlined above are employed in HSCT optimization studies so that the detrimental effects of numerical noise are reduced or eliminated during optimization. Results from sample HSCT optimization studies involving five and ten variables are presented here to demonstrate the utility of the two modeling methods. System requirements: PC, World Wide Web Browser and PDF reader. Available electronically via Internet. high-speed civil transport aerodynamics parallel computing Virginia Tech Aerospace and Ocean Engineering Bernard Grossman Committee Chair Raphael T. Haftka William H. Mason Layne T. Watson Eugene M. Cliff unrestricted http://scholar.lib.vt.edu/theses/available/etd-5742153049751491/ " s1998 vau| sm 00| 0|eng d" (VPI) etd-55691079662221 Gonzalez, Reinaldo J. Raman, Infrared, X-ray, and EELS Studies of Nanophase Titania Computer data - 10 file(s) Blacksburg, Va. University Libraries, Virginia Polytechnic Institue and State University, 1998 Thesis (PHD)--Virginia Polytechnic Institute and State University, 1998-07-13 Includes bibliographical references. Sol-gel titania particles were investigated, primarily by optical techniques, by systematically varying synthesis, sample handling, and annealing variables. The material phases investigated were amorphous titania, anatase TiO2, and rutile TiO2. Annealing-induced phase transformations from amorphous TiO2 to anatase to rutile were studied by Raman scattering, infrared reflectivity, infrared absorption, x-ray