Accurate finite volume solution algorithms for the two dimensional Navier Stokes equations and the three dimensional Euler equations for both structured and unstructured grid topologies are presented. Results for two dimensional quadrilateral and triangular elements and three dimensional tetrahedral elements will be provided. Fundamental to the solution algorithm is a technique for generating multidimensional polynomials which model the spatial variation of the flow variables. Cell averaged data is used to reconstruct pointwise distributions of the dependent variables. The reconstruction errors are evaluated on triangular meshes. The implementation of the algorithm is unique in that three reconstructions are performed for each cell face in the domain. Two of the reconstructions are used to evaluate the inviscid fluxes and correspond to the right and left interface states needed for the solution of a Riemann problem. The third reconstruction is used to evaluate the viscous fluxes. The gradient terms that appear in the viscous fluxes are formed by simply differentiating the polynomial. By selecting the appropriate cell control volumes, centered, upwind and upwind-biased stencils are possible. Numerical calculations in two dimensions include solutions to elliptic boundary value problems, Ringleb’s flow, an inviscid shock reflection, a flat plate boundary layer, and a shock induced separation over a flat plate. Three dimensional results include the ONERA M6 wing. All of the unstructured grids were generated using an advancing front mesh generation procedure. Modifications to the three dimensional grid generator were necessary to discretize the surface grids for bodies with high curvature. In addition, mesh refinement algorithms were implemented to improve the surface grid integrity. Examples studied include a Glasair fuselage, High Speed Civil Transport, and the ONERA M6 wing. The role of reconstruction as applied to adaptive remeshing is discussed and a new first order error estimator is presented. Numerical examples of the remeshing procedure include both smooth and discontinuous flows. / Ph. D.

This thesis is a study of classical and quantum gravity with Ashtekar variables. The Ashtekar constraints are shown to capture the essence of the constraints and constraint algebra of General Relativity in four dimensions. A classification scheme of the solution space of the Ashtekar constraints is proposed and the corresponding physics is investigated. The manifestly covariant equations of motion for the Ashtekar variables are derived. Explicit examples are discussed and new classical solutions of General Relativity are constructed by exploiting the properties of the Ashtekar variables. Non-perturbative canonical quantization of the theory is performed. The ordering of the quantum constraints as well as the formal closure of the quantum constraint algebra are explored. A detailed Becchi-Rouet-Stora-Tyutin (BRST) analysis of the theory is given. The results demonstrate explicitly that in quantum gravity, fluctuations in topology can occur and there are strong evidences of phases in the theory. There is a phase which is described by a topological quantum field theory (TQFT) of the Donaldson-Witten type and an Abelian antiinstanton phase wherein self-interactions of the gravitational fields produce symmetry breaking from SO(3) to U(1). The full theory is much richer and includes fluctuations which bring the system out of the various restricted sectors while preserving diffeomorphism invariance. Invariants of the quantum theory with are constructed through BRST descents. They provide a clear and systematic characterization of non-local observables in quantum gravity, and can yield further differential invariants of four-manifolds. / Ph. D.

The expanding field of executive development programs was investigated. The field was found to be active and influenced by a number of different academic disciplines. However, no overall structure exists for guiding the examination, comparison or discussion of executive development programs. This work provides a structure in the form of a "framework for inquiry." The framework is then used to describe and analyze seven focus programs. Included in this study are the programs of the Naval Aviation Administration, Federal Executive Institute, Harvard University, U.S. Army War College, Center for Creative Leadership, Bell South, and the World Bank. All programs are thoroughly described and analyzed, but not evaluated. Use of the framework facilitates a comparative review of the similarities and differences of programs. This study demonstrates how a number of factors of the framework can combine to give a program a distinct overall identity. It also shows how certain factors may be very important in contributing to the identity of one program, but not important in contributing to another. This underscores the value of using the framework for inquiry in its entirety when studying executive development programs. This work also demonstrates other uses of the framework, including selection of a program by a prospective participant and development of a program by a sponsoring organization. The dissertation concludes with a prescriptive call for "program coherence," in which executive development program managers consciously align all program factors toward establishing and maintaining overall program identity. This identity should be consistent with the individual and organizational development goals of the program. / Ph. D.

Means of achieving rapid, efficient separations of analytes are explored in detail, with particular emphasis on the use of chromatographic and electrophoretic theory as an aid in system design and optimization. The benefits of miniaturization of chromatographic systems are assessed. First, the utility of semi-micro Ion Chromatography is explored by the manufacture of 2mm ID analytical and suppressor columns and a micro-conductivity cell. The quality of the columns and detector cell are evaluated by the separation of a test mixture and the calculation of peak variance contribution of the detector cell. The use of readily available analytical scale instrumentation for semi-micro IC is demonstrated. Next, a further downsizing of the IC system is described, in which 530μm ID fused silica tubing is utilized for column manufacture. In this case, a suppressor column is not used and UV detection is employed in the analysis of nucleoside monophosphates. Again, column performance characteristics are measured and noted. Application of this system to the separation of a hydrolysed nucleic acid sample demonstrates the feasibility of the technique to the analysis of volume-limited samples in low concentration with notable sensitivity. The benefits of a miniaturized liquid chromatographic system under pressure-driven flow is studied and the improved permeability of micropacked capillary columns is exploited in the manufacture of several 25 to 30cm columns which achieve high efficiencies with relatively low pressure drops. Van Deemter plots illustrate the performance characteristics of the columns. Finally, electroosmotic flow is studied as the motive force for liquid chromatographic separations. This combination of two techniques, packed capillary liquid chromatography and capillary electrophoresis, results in a system which achieves good resolving power through maximization of selectivity and efficiency. / Ph. D.

To incorporate users' opinions into the evaluation phase early in the software documentation development stage, the critical incident technique was used to identify usability problems in a fault free software user document. The critical incidents were used to modify the original document to improve its usability. To test whether the modified document was better in usability than the original document, an experiment was conducted to compare objective measures and subjective ratings. Four objective measures included number of errors, task completion time, document reading time, and number of personal helps requested. In addition, subjective ratings on ease of use, accuracy of information, inconsistencies, ease of learning, completeness, helpfulness of figures, and ease of understanding were compared between the two documents. The analyses showed that for 3 of 4 objective measures and 7 out of 9 subjective ratings, the new document was better and easier to use. In some cases, this difference was task specific. Generally, easier tasks accounted for better objective measures and more favorable subjective ratings. / Master of Science

Model-following control design methodology is introduced for nonlinear plants and models. The plant equations are considered to be linear in the control input. Dynamic matching conditions are presented and the resulting error dynamics are given. The stability of error dynamics is ensured, using Liapunov's second theorem; by modifying the model state rates, which effectively introduces error feedback. The methodology is applied to two problems. Motion control of an n-link manipulator with torque controllers on each linkage, and control of an aircraft lacking direct control of lift and side force. The former represents the systems where all of the degrees of freedom can be controlled, and the latter represents the systems where only some of the degrees of freedom can be controlled. The aircraft control problem is analyzed in more detail. The resulting control law does not require any explicit gain scheduling, but instead, requires estimates of the stability and control derivatives. A method is proposed to compensate for actuator dynamics. The control law is then verified by simulating some maneuvers on the aircraft model provided for the AIAA Controls Design Challenge, which includes nonlinear and full-envelope aerodynamic and engine models, and rate and position limited controls. The maneuvers simulated include a level acceleration and a 3-g turn. / Master of Science

Previous investigations have shown that metabolic rate remains elevated for a period of time after the cessation of exercise. While other investigations have examined the effect of intensity and duration of prior exercise, the purpose of this study was to examine the effect of exercise mode and the employment of different muscle masses on the elevation of post-exercise metabolic rate (EPOC). Fifteen non-smoking, physically active females (21.1 ± 1.3 years; 21.4 ± 4.6 %BF) volunteered for this investigation. Each subject completed a graded maximal exercise test (GXT) on the Monark 880 cycle ergometer (Max HR=192.5 ± 2.3 bpm; Max V02=2.68 ± O.lll/min; Max RPE=19.5 ± 0.1) from which a heart rate corresponding to 70% V02max was chosen. Subjects then exercised on either a Monark 880 cycle ergometer (LE) or the Schwinn Airdyne (ALE) in random order for thirty minutes at the prescribed heart rate (HR). Exercise bouts were separated from each other and from the GXT by at least 48 hours. Workloads were monitored in five minute intervals and adjusted to maintain the appropriate heart rate. The mean exercise heart rates were 172.5 ± 2.8 bpm for the LE bout and 170.0 ± 2.8 bpm for the ALE bout, respectively. Two-way repeated measures ANOVA revealed no significant difference \r >0.05) between exercise treatments in terms of HR or V02. Repeated measures trend analYSis revealed no significant difference in either EPOC or post-exercise heart rate between the two treatments across a one-hour seated recovery period. There was also no significant difference (p>O.05) in excess post-exercise caloric expenditure during the recovery period as a result of the different exercise treatments. Therefore, this suggests that neither exercise modality nor the distribution of work over a larger muscle mass had an effect on EPOC when exercise intensity and duration were held constant. / Master of Science

This study investigated the effects of group cohesiveness on group conformity, and on member satisfaction. In this study, group cohesiveness, group conformity, and member satisfaction were considered to be constructs. The definition of the construct of group cohesiveness included the interrelated components of psychological closeness, interpersonal liking, group affiliation, and trust. The definition of group conformity included the components of compliance and acceptance. The definition of member satisfaction included the components of satisfaction with the group decision, satisfaction with the group process, and satisfaction with the group atmosphere. The major research hypotheses suggested that group cohesiveness has an effect on member satisfaction, on acceptance of social influence, and on compliance with the group. The study examined also the role of the moderating variables of self-esteem, sociometric status, and gender. A total of 77 undergraduate students at Virginia Tech participated in a decision-making experiment. The students were led to believe they were assigned to congenial work groups based on their responses to pre-experimental questionnaires. In fact, the students were randomly assigned to groups, and randomly assigned to one of the two treatment conditions high or low cohesiveness. Verbal and written manipulation instructions were used to induce high and low cohesiveness in the groups. This manipulation was significant, and moderately successful. During the experiment, the subjects had to work on two rank-ordering exercises as individuals, and as groups. The experimental results suggested that group cohesiveness and member satisfaction are significantly correlated. Subjects who perceived their group to be highly cohesive were more satisfied with the experimental group meeting than subjects who perceived their group to be less cohesive. There was no evidence for a relationship between group cohesiveness and acceptance of social influence. This finding, however, should not be generalized since it is possible that group cohesiveness has no immediate impact on acceptance in emerging groups. The results also suggest there is a relationship between group cohesiveness and compliance. Students who were assigned to the high cohesiveness treatment complied more frequently with their group than students who were assigned to the low cohesiveness treatment. / Master of Science

The purpose of this study was to identify the relationship between the topics addressed in FaciJitiesDesign&Managementfrom January 1984 to October 1991 and the responsibilities of facility managers as identified by the International Facility Management Association (IFMA). In addition to the eight IFMA responsibilities't five researcher-developed categories were included. Content analysis of the title and abstract of each feature article (N=413) of the journal was utilized. Of the 10 primary categories (eight primary categories identified by lEMA and two categories developed from the literature review) which were applied to 273 articles, the responsibility most frequently addressed in the journal was interior planning, followed by responsibilities in interior installation, maintenance and operations, facility management, architecture and engineering services, budgeting, space management, real estate, longrange planning, and facility management in foreign countries. As identified by the analysis of the journal articles, the primary categories of interior planning and interior installation may be considered as the most important tasks of facility management. The category of general facility management knowledge which was not included in the original IFMA list was addressed frequently and may be considered as an evolving responsibility. Three additional categories of responsibility not included in the original 10 categories were identified in the analysis and applied to 140 articles. These three categories encompassed issues related to organization, office technology, and implementation of facility management. The category most frequently addressed among these three was office technology. The findings of this study support several suggestions. Planning and designrelated responsibilities were identified as the major tasks of facili ty management departments. Related concerns included changing furniture needs to accommodate technological changes, increasing attention to employee welfare in the office design, and the increasing effect of office technology on facility management. These same topics reflect needs for continued education among practicing professionals. Similarly, facility management educational programs must develop needed planning and design-related skills as well as a knowledge of real estate and tax law. accounting and financial management, and use of computerized facility planning and building system technologies. / Master of Science

This study examined the effects of disk speed, temperature and anvil condition on chip size from sawmill residues of Loblolly pine (<i>Pinus taeda</i> L.). Objectives were: 1) to document the effects of disk speed, temperature and anvil condition on the amount of over thick, oversize, accept, pin and fine chips produced from edgings, 6"x6" cants and trim blocks and 2) to recommend changes in processing sawmill residues to minimize the production of over thick, pin and fine chips. Ten trials were conducted at the Chesapeake Corporation's West Point, Virginia hardwood sawmill using a Fulghum Industries 60-in. (152-cm) diameter, six-knife, vertical disk chipper. Tests were conducted at approximately 80, 70, 60, 50 and 40% of the full disk speed of 707 rpm for the three material types. It was found that decreasing disk speed decreases the amount of pin and fine chips and increases the amount of over thick chips for all material types. The maximum amount of accept and oversize chips was obtained at 50% disk speed. If 50% efficient secondary processing of the over thick chips is achieved, the maximum amount of oversize and accept chips would be produced at 40% disk speed. All frozen and chilled residue types tended to produce less oversize chips and significantly more pins and fines than wood at ambient temperature. A worn anvil caused a significant increase in pins and fines while causing a significant decrease in oversize chips from the cants. Design changes are suggested to reduce the amount of over thick chips produced by vertical disk chippers. / Master of Science