A computational study of the flow in a tandem inducer/impeller rocket pump has been performed using a 3D elliptic flow program including viscous effects. The axial inducer has four blades and the centrifugal impeller has eight main blades and sixteen splitter blades. The purpose of this thesis is to investigate the flow in the turbopump, and check its proper design. A literature review discusses both elements of the pump, and then analyzes the possible matching configurations. More details are given for the geometry of interest. The generation of a single zone 3D grid for the tandem combination is then presented in detail, after which simpler grids are derived for the inducer alone. The results of the 3D tandem inducer/impeller calculation are presented extensively to provide good knowledge of the flow inside this little investigated configuration. Velocity vectors, static pressure and rotary stagnation pressure are shown in meridional and blade-to-blade views. A balanced flow split is achieved in the impeller main-blade passages. Cavitation inception is also discussed. Additional 3D calculations are performed for the inducer alone, with varying exit geometry (axial or radial). Comparisons of geometry influence on the inducer flow are carefully investigated, as well as the influence of the impeller. The impeller slightly modifies the inducer exit flow but not its overall performance. As a consequence, it is found that separate design calculations could be performed for the inducer and the impeller. The latter would use the inducer circumferentially averaged exit flow as its inlet conditions. It is suggested that impeller suction performance be optimized using tandem inducer/impeller calculations. / Master of Science

Previous studies demonstrate that members of the strictly aerobic genus Gluconobacter produce detectable quantities of hydrogen sulfide (H₂S) when incubated in SYP medium (5% sorbitol, 1% yeast extract, and 1% peptone) containing thiosulfate. This finding is puzzling, since the microbial evolution of H₂S is characteristic of anaerobic or facultative bacteria. The goal of this research was to determine the physiological role of H₂S evolution for the gluconobacters. A methylene blue method was used to quantify the amount of H₂S evolved from cultures grown aerobically for 3 days at 28°C. Five of the six tested strains of gluconobacter evolved from 6 to 68 μg of H₂S. Strains which grew to a higher density (> 300 μg cell protein/ml ) evolved between 10 and 68 μg of H₂S. Strains which grew to a lesser extent (< 140 μg cell protein/ml ) evolved no more than 6 μg of H₂S. Uninoculated SYP medium containing 1% thiosulfate showed no evidence of H₂S evolution; however, sterile SYP medium with decreasing concentrations of yeast extract and peptone showed increasing amounts of H₂S evolved. When SYP medium was exhausted by gluconobacter growth for 72 hours, then supplemented with thiosulfate, filter sterilized, and incubated for 3 days at 28°C, these sterile solutions evolved over 400 μg of H₂S. A drop in pH. similar to that which occurs during gluconobacter growth, is not sufficient to evolve H₂S. My results to date suggest that H₂S evolution results not from gluconobacter metabolism, but rather from spontaneous decomposition of thiosulfate and the depletion of media components during growth. / Master of Science

Master of Science

The purpose of this study was to document pictorially the exterior architectural style and the interior configurations of Virginia high schools, and to relate these designs to major curricular trends. This study, using historical research methods, will preserve Virginia's secondary educational institutions for future resource. A history of the high school in Virginia was developed as a background for the study of school architecture. The methodology used in this study produced a selection of high school buildings which best represented an architectural period, beginning with the oldest high school building still in use to the most recently constructed schools. All 284 public high schools were surveyed to obtain data on the date of construction, condition of the structure, presence or absence of additions, and other pertinent data concerning the building. From this population, seventeen schools were chosen to represent school buildings in each of the decades covered. Selection of the schools was based on the following criteria: 1) Date of original construction; 2) Completeness of original structure (The pristine element of an existing building is dependent upon the absence of major renovations, changes, or additions to the structure which would drastically alter the architectural style.); 3) Overall rating by the building principal (condition, design, and functional ability to serve students, staff, and community); 4) Noteworthy architectural or unique educational features; and 5) Subjective comparison, (examining floor plans and photographs). Each of the buildings in the sample was visited to obtain data relating to curricular emphasis in the design. Each architectural period was researched for significant educational and curricular trends that may have influenced high school design. The outcome of this study was a document containing a written and pictorial history of the architectural and curricular features of Virginia high schools. / Doctor of Philosophy

Urbanism and its associated architecture not only takes place in designated city areas but also in the Realm of the Middle Landscape. Although it is hardly possible to invent a new architecture, the necessity remains to think about questions of urbanism and its built structures in the context of history, technology and sociology. One interpretation which challenges the current urban development, such as the issue of the sprawl of mid size towns, has the potential to direct planning tools and clarify intentions towards a more differentiated strategy of orientation. This approach to design opens the possibility to develop a higher level of sophistication by articulating building elements within classical parameters such as proportion, geometry and composition. The filtering into a modern context which includes the knowledge of attributes of contemporary materials and technology will facilitate the process of transfer. / M. Arch.

Ph. D.

Master of Architecture

This investigation examined the ability of the Veterans Specific Activity Questionnaire (VSAQ) to predict the functional capacities (expressed in metabolic equivalents or METs) of twenty male participants previously diagnosed with CAD who were referred for exercise testing as part of their participation in a community based exercise program. On the morning of their normally scheduled GXT, each individual completed the VSAQ and was administered a maximal exercise test on a treadmill utilizing a ramp style protocol based on their self estimation of functional capacity. Respiratory gas exchange values were recorded throughout and analyzed via stepwise linear regression with respect to several experimental and demographic variables such as age, BMI, percent body fat and time since entering a cardiac maintenance exercise program. The only variable to contribute significantly to the prediction of FC with regard to exercise capacity as measured by respiratory gas analysis was the VSAQ. The VSAQ explained 22.% of the variance in actual performance and this variable only showed a modest association with the criterion measure (r = 0.47 SEE 2.25, p <0.05). A similar finding was noted when this criterion of exercise performance was estimated from treadmill speed and grade equations. In this case, the VSAQ accounted for 34% of the variance in exercise performance, i.e., r=0.58 (SEE 2.16, p <0.05). The final regression equation by which the VSAQ might be used to predict exercise capacity by the gas exchange criterion was: METs = 4.21 + 0.50(VSAQ). The final regression equation for prediction of MET exercise capacity by speed/grade at peak exercise was: METs = 4.60 + 0.65(VSAQ). / Master of Science

The purpose of radar signal processing is to extract desired data from radar signals. Testing of the radar signal processor requires that one produce a test consisting of a sequence of digitized radar sensor data. If the signal processor is modeled in VHDL then the sequence of sensor data will be applied to the model in a VHDL test bench. Generation of the sensor data and sensor models for VHDL testbenches is a labor intensive task which cannot be performed manually. This thesis concentrates on the transformation of the mathematical representations of Synthetic Aperture Radar signals and sensors into VHDL models, and provides the mathematical underpinning for the other testbench work. Cadence/Comdisco SPW is used to describe the behavioral model of the test bench, which is hierarchically constructed using the primitives in the SPW library. A parameterized VHDL model is constructed from the block diagrams in SPW to generate the test for the VHDL signal processing model under test. / Master of Science

Single story, rigid gable frames are commonly used by the metal building industry for light, industrial buildings. These rigid gable frames are usually constructed of built-up, web tapered, columns and rafters for reasons of economy. The tapering of the webs optimizes the members to develop a fully-stressed design. The purpose of this study was to investigate the AISC LRFD strength of the rigid knee portion of gable frames. The experimental portion of this study was sponsored by Kawada Industries, Inc., Costa Mesa, California. Eight specimens consisting of a tapered column and a portion of the tapered rafter were tested to failure under three types of loading that approximated the gravity, lateral, and cyclic load cases. The analytical portion of this study investigated the LRFD strength of the eight tapered knee specimens. The calculated LRFD strengths were compared to the experimentally obtained capacities. It was concluded that the LRFD shear strength provisions were overly conservative. The LRFD shear strength for tapered members was limited to the elastic or inelastic buckling strength of the web plate. Procedures for the application of the LRFD tension field action model to account for the post-buckling strength of tapered webs were presented. The application of tension field action to end panels, panels with large aspect ratios, and hybrid girders was also addressed. It was shown that the application of the LRFD tension field model to tapered members produced less conservative results. / Master of Science