Analytical expressions for the deflection surface of symmetrically loaded circular and annular plates resting on discrete point supports are derived. The formulation of the problem is based on classical small deflection plate theory. It is also assumed, in the formulation, that the supports are situated equal distances apart on a single concentric circle. There is no restriction placed on the number of supports or on the size of the support circle which could be as large as the plate itself or as small as the size of the hole of the annular plate. The singularity effects associated with the concentrated supports on the plate problems considered here are accounted for in the solution, by drawing an analogy from the Michell's solution to a clamped circular plate subjected to an eccentric point load. This procedure yields solutions in much more suitable form for practical numerical problems than other known methods. In the case of circular plates on multipoint supports, explicit solutions are given to a number of loading conditions. Solutions to a uniformly loaded circular plate on multipoint supports are compared with the published experimental results; the conclusions are favorable. From the numerical data obtained for a uniformly loaded circular plate on multipoint supports, a procedure is outlined for obtaining contour maps of deformed uniformly loaded plates with discrete supports on two support circles. Solutions to annular plates on multipoint supports are derived for the first time. By utilizing this result, design charts are drawn to indicate the optimum size of the support circle, which would produce least peak-to-peak displacements for any given size of hole, and a specified number of supports. Contour maps associated with annular plates on three point supports are also drawn to illustrate the influence of support circle on the displacements. It was found that when there are a fewer number of supports and/or the size of the hole is small, the magnitude of peak-to-peak displacements and the size of the optimum support circle are considerably different from the associated quantities when the support is a continuous ring. / Ph. D.

A transition calculus is developed for describing and analyzing the dynamic behavior of logic circuits. Boolean partial derivatives are introduced that are more powerful and applicable to a wider class of problems than the Boolean difference. The partial derivatives are used to define a Boolean differential which provides a concise method for describing the effect on a switching function of changes in its variables. It is shown that a nonconstant function is uniquely determined by its differential, and integration techniques are developed for finding a function when its differential is known. The useful concepts of exact integrals, compatible integrals, and integration by parts are introduced and the conditions for their existence are established. Algorithms for both differentiation and integration are simply implemented using Karnaugh maps. / Ph. D.

A comparison of the results of Experiments 1 and 2 vividly demonstrates the vulnerability of ram spermatozoa to the stress of freeze-thawing. When ram spermatozoa were subjected to freeze-thaw stress, there was more variation among treatments reflected in maintenance of both intact acrosomes and motile life (Experiment 2, Table 9) than when unfrozen sperm were studied (Experiment 1, Table 5). The influence of glycerol and Tris are particularly noteworthy. Though rate of thaw is not part of the surrounding media, it does control the amount of time the cells are subjected to an even more hostile environment (high salt concentrations) encountered near the melting point of ice. Therefore, the benefit of higher thaw temperatures and resulting faster thaw rates was undoubtedly due to minimizing exposure time of spermatozoa to this adverse condition. / Master of Science

The aim of this study was to apply the hypothesis of functional decentralization to the United States Court of Appeals for the Fourth Circuit for the years 1968-1970. It was expected that there would exist a number of smaller specialized sub-courts handling particular issue areas. While a number of statistically significant individual patterns were found, and three specialized sub-courts were identified, these findings cannot be interpreted as substantively significant. The anticipated pattern was that a large percentage of the issue areas would emerge as specialized. The specialized sub-court found in the Libel issue area is negated by the fact that the issue area had only seven cases. In terms of the overall pattern of behavior of the court the two specialized sub-courts remaining cannot be interpreted as having any substantive significance. That the anticipated patterns of behavior were not found may have two explanations. The first is that the seating patterns discerned occurred solely through chance. Thus, for the period 1968-1970, assignment of judges to appellate panels in the United States Court of Appeals for the Fourth Circuit was done on a completely random basis. The second possible explanation is that there exists a fault in the research design which led to inability to reject the null hypothesis. There are several areas of potential error. The first lies in the typing of cases. Inevitably, unless the researcher is skilled in the principles of law and has sufficient time to study every case before typing, some forcing of cases into inappropriate case types will occur. Future researchers employing this technique will have to decide for themselves how much forcing is acceptable. In this research, approximately five per cent of the cases were forced. When spread over twenty-four primary case types, this five per cent may not have had any significant effect, but the potential for error cannot be discounted nor is it possible to assume that the forced cases were distributed evenly through the range of case types. / Master of Arts

Morphological studies in the past have been almost exclusively confined to the description and illustration of adult females. Morphological studies of Diaspididae were further restricted to the pygidial area. This study is an attempt to provide complete descriptions, illustrations, and measurements for morphological characters for all life stages of C. americana Johnson and C. kosztarabi Takagi and Kawai. The majority of the specimens were obtained from weekly collections of local infestations on the Virginia Polytechnic Institute and State University campus. Freshly collected scale insect samples were mounted in both Hoyer's medium and Canada balsam for microscopic study. The biologies of the two species in Blacksburg, Virginia were studied using weekly collections. Both species were bivoltine. C. americana overwintered mainly in the egg stage; the first brood hatched about April 20, and the second brood about July 25, in 1972. C. kosztarabi overwintered as fertilized females. Eggs were laid in early spring hatching about May 28 in 1973, and the eggs of the second generation began hatching about August 10, in 1972. Dimorphic males of both species were collected. C. americana males exhibited apterous and brachypterous conditions. C. kosztarabi males were either apterous or pterous. Several species of hymenopterous parasites were reared from each species. / Master of Science

<u>Diplostomulum trituri</u> is associated with pathological damage which includes increased size of the ventricles and loss of neural tissue. Neurophysiological symptoms of parasitism include sluggish behavior and poor reflexes. Black material was observed in the lumen of the intestinal ceca. Several mesocercariae were observed to be attached to the neural tissue by their oral sucker. In 150 newts examined from Mountain Lake, Giles County, Virginia, the incidence of infection with <u>D. trituri</u> was 100 percent. The total number of parasites in the brain and surrounding area ranged from 2 to 300. The number of mesocercariae in the ventricles of the brain was approximated to range from 5 to 30. The attempts to recover the encysted larval stage and/or adult failed using Japanese quail, mallard ducks, raccoon, muskrat, opossum, domestic cat, and fish from families Salmonidae, Catostomidae, Cyprinidae, and Centrarchidae as experimental definitive hosts for <u>Diplostomulum trituri</u>. / Master of Science

Sixty-seven adult and 42 subadult female gray squirrels (Sciurus carolinensis) were collected over a period of one year between December, 1966 and November, 1967 in the vicinity of Blacksburg, Virginia. Each squirrel was classified as being in one of four reproductive states (vaginal orifice closed, vaginal orifice open, pregnant, or lactating). Differences in ovarian and uterine characteristics due to month, age, and reproductive state were analysed by analysis of variance and a multiple range test. Pregnant adults had significantly (P<0.05) greater paired ovarian weights than lactating adults or those adults with a closed vaginal orifice. Uterine weights in the four reproductive states were all significantly (P<0.05) different, with pregnant adults highest, adults with open vaginal orifices next highest, lactating adults next highest and adults with closed vaginal orifices lowest. Pregnant adults had significantly (P(O.05) more tertiary follicles and significantly (P<0.05) higher sums of follicular diameters than all other reproductive states. Squirrels with open vaginal orifices had significantly (P<0.05) higher average diameters of the four largest follicles than all other reproductive states. Ovarian and uterine weights of subadults were less than adults during most months. Ovarian and uterine weights increased in late winter, decreased in early spring, increased during the summer and decreased in the fall. Follicular development was more variable, but showed general increases in the summer months. The seasonal trends reflected the frequency of occurrence of the various reproductive states in the monthly samples. Two experiments were conducted on captive female gray squirrels. In the first experiment it was determined that FSH-P can cause the formation of luteal glands in the absence of HCG injection. LH contamination of FSH-P probably caused the luteinization. There were no significant differences in ovarian response between squirrels receiving HCG subcutaneously and those receiving it intravenously after pretreatment with FSH-P. In the second experiment, 2.0 mg FSH-P/d~ on days 1, 2, 3, 4, 5, 6, and 7 with subcutaneous injection of 200 IU HCG on day 13 produced significantly (p<0.05) more luteal glands than 200~ FSH-P on days l~ 2, 3, 4, 5, 6, and 7 with subcutaneous injection of 200 IU HCG on day 5. However, there were no significant differences in development of tertiary follicles. Squirrels treated with NIH-FSH-S-6 and HCG had development of large tertiary follicles with no luteinization. / Master of Science

At the present time, millions of dollars are being lost by major airlines each year because of the inability of high density air terminals to efficiently service all of the demands placed upon them during peak periods of demand. Up to the present time, studies involving congestion have been aimed primarily at the implementation of computerized techniques to aid the air traffic controller during peak demand periods. By scheduling aircraft in a given system in a different manner, delay, caused by congestion, could possibly be reduced at high density terminals even more than it has been reduced by the results obtained from previous studies. The approach taken in this study involves testing different heuristic scheduling algorithms, based on what has been done previously, to determine what extent total system delay can be reduced. The method of approach which was followed was based on a simulator which models aircraft movement between N major terminals. For each scheduling algorithm developed, hourly statistics related to the number of aircraft demanding service, average departure delay, and average arrival delay were calculated along with total system delay times for arriving and departing aircraft. The results obtained from these algorithms were analyzed and compared with the scheduling algorithm which resulted in a reduction in delay being examined in greater detail to determine whether or not such a schedule would actually be feasible and worthwhile. / Master of Science

The effect of surface finish on the transfer of polychlorotrifluoroethylene (PCTFE) to mild steel was studied using a radio-tracer technique. A pin-on-disk apparatus was used in conjunction with neutron activation of PCTFE to study the initial stages of transfer. Quantitative transfer and friction data were obtained as functions of surface finish and the number of repeated passes of polymer over mild steel. Qualitative supporting evidence for postulated transfer mechanisms was obtained using scanning electron microscopy. The results showed that bulk transfer of PCTFE to mild steel does occur at room temperature. Initial transfer to polished (0.10 um - rms) surfaces, abraded (0.81 um - rms) surfaces, and glass bead blasted (1.73 um - rms) surfaces was attributed to an abrasive wear mechanism. An apparent translation to adhesive wear was observed during later stages of transfer. This transition occurred much sooner with the polished surface than with the rough surfaces. This work also demonstrated that a radio-tracer technique could be effectively applied to the study of polymer wear. The minimum mass detection limit with this technique was 0.3 ug. This sensitivity is at least one order of magnitude better than that obtained with reported polymer wear measurement methods. / Master of Science

Today, increases in expenditures are creating tremendous strains on the financial resources of state and local governments. As these demands for services increase, the state and local governments continuously find their financial resources incapable of bending to meet these needs. Currently state and local governments together combined spend twice as much as the federal government to provide public services to the citizens. Education, roads, welfare, public health, hospitals, police, sanitation are all state and local responsibilities with the cost of providing these services falling primarily upon state and local sources of revenue. Consequently, state and local taxes have been raised almost to the saturation point and the bases of old taxes have had to be enlarged. / Master of Arts