The possibility of acetone shock loadings to phenol acclimated systems resulting in sequential substrate utilization and increased effluent phenol concentrations was evaluated. Phenol acclimated batch and continuous-flow systems, developed with seed from a municipal wastewater treatment plant, were shock loaded with acetone, bacto-peptone, and domestic primary effluent. Phenol and acetone utilization rates were then monitored using direct injection gas-liquid chromatography. The results of the investigation indicated that, under the described experimental conditions, qualitative shock loading of phenol acclimated/utilizing cultures had no significant effect on effluent phenol concentrations. Variations of system pH, however, were found to have extreme effects. / Master of Science

It is well known that the cost of large-scale software systems has become unacceptably high. Software metrics by giving a quantitative view of software and its development would prove invaluable to both software designers and project managers. Although several software quality metrics have been developed to assess the psychological complexity of programming tasks, many of these metrics were not validated on any software system of significant size. This thesis reports on an effort to validate seven different software quality metrics on a medium size data base system. Three different versions of the data base system that evolved over a period of three years were analyzed in this study. A redesign of the data base system, while still in its design phase was also analyzed. The results indicate the power of software metrics in identifying the high complexity modules in the system and also improper integration of enhancements made to an existing system. The complexity values of the system components as indicated by the metrics, conform well to an intuitive understanding of the system by people familiar with the system. An analysis of the redesigned version of the data base system showed the usefulness of software metrics in the design phase by revealing a poorly structured component of the system. / Master of Science

The purpose of this thesis is to examine the possibilities for the revitalization of an abandoned railroad station and to derive from the project significant issues and strategies which can be applied to any reuse project. / Master of Architecture

A theoretical study of the deformation fields of the cornea under internal pressure is presented. The general elasticity equations describing a thin shell of variable thickness are solved using finite difference techniques. To gain insight into the natural corneal structure, the constant thickness case is compared to one of normal thickness. The bending stresses are found to influence the cornea's natural curvature. In the third case, the normal thickness is increased 10% to model the edematous state resulting from the incisions made during radial keratotomy. A comparison of the third case reveals the increased thickness in the peripheral cornea makes a minor contribution to the displacement; but moreover, the curvature change is opposite to that desired from radial keratotomy. The incisions are necessary to weaken the lateral support of the shell allowing the displacement and change in curvature which corrects myopia. / Master of Science

Twelve obese normotensive females were studied to determine the effects of either a 71% carbohydrate (HC) hypocaloric diet or a 33% carbohydrate (LC) hypocaloric diet concommitant with an aerobic exercise program on sodium (Na) balance and blood pressure changes. Subjects participated three times a week in a submaximal periodic exercise session and were placed on one of the diets for 28 days. Posttreatment, each participant consumed a 1000 kcal mixed diet while remaining in the exercise program. Daily Na losses were measured by 24 hr urine collection, and blood pressure measurements were made weekly. Both treatment groups significantly decreased in weight with LC losing more than HC (8.0 kg by LC group; 6.7 kg by HC group). Although urine Na balance was negative for the first 2 days of both VLCD's, Na excretion fell over time to result in net Na retention over the experimental period. Though the LC group lost more Na during the first week than EC during subsequent weeks, the differences between groups were nonsignificant. There were no significant differences between groups in serum Na or urine Na balance. However, Na urinary loss significantly decreased across time. Both systolic and diastolic blood pressure decreased non-significantly an average of 4% from baseline values throughout the treatment (5.2/4.0 mmHg in the HC group and 4.3/2.3 mmHg in the LC group). Carbohydrate inclusion in both diets was found to be effective in retaining Na after 4 days on a VLCD. Changes on different postural positions did not reveal evidence of hypotension. Overweight normotensive individuals did not reduce blood pressure values below normal levels. / M.S.

A general approach is presented for the estimation of spacecraft attitude from rate gyroscope measurements of angular velocity and indirect inertial orientation measurements obtained from a pair of star sensors. The estimation algorithm is developed in such a way that the measured minus estimated angular velocity residuals are consistent with the apriori knowledge of the instrument error variance. The angular velocity history is modeled as a Fourier Series. whereas the attitude is modeled as the solution of the appropriate kinematic differential equations. The study presented addresses computer implementation issues and provides numerical results from several simulated attitude and velocity histories. The software is presented in FORTRAN code in an appendix. / Master of Science

The objective of this study was to estimate the milk supply response of Virginia dairy farmers, including estimation of supply elasticities with respect to relevant prices. The supply response was estimated using linear regression techniques and quarterly data from 1965 through 1982. The hypothesis that producers are profit maximizers was not rejected. For the entire period the estimated supply responded positively to own-price changes, negatively to feed and cull-cow prices, and positively to technical change using time as a proxy variable. Estimated own-price elasticities for total and Grade A milk supplies were 1.19 and 0.94, respectively, and for Grade B milk supply was 2.11. Responses to own-price changes were completed within two years. The Chow test for structural change in the estimated coefficients of explanatory variables resulted in rejection of the hypothesis that supply responses were constant over the entire period. Producers continued to adjust supply positively to own-price changes for the years 1974 through 1982. However, estimated own-price elasticities for total, Grade A and Grade B milk supplies decreased to 0.84, 0 80 and 0.97, respectively. Technological efficiency, using time as a proxy, continued to contribute to increased output. Producers did not respond to feed price changes. Grade A supply response to own-price changes was completed within three years, and it took two years for total and Grade B supply to complete responses to own-price changes. / M.S.

The sludge blinding coefficient, β, was evaluated in this experimental study, to determine if β could be used as a useful characterization parameter for sludge filterability. Fresh activated sludge, activated sludge aged at room temperature, primary sludge, alum sludge, and a calcium carbonate slurry were filtered using a Buchner funnel apparatus and varying size filter media at various pressure differentials. Particle size measurements were also performed on the above mentioned sludges using an automated particle size analyzer to examine the impact of particle size and size distribution on β. Effects of conditioning, elutriation, supernatant removal, and replacement on β were also studied. In general, β correlated well with the average specific resistance, indicating that it could be useful in predicting a sludge filtration pattern. β was found to increase as the mean particle size of a sludge decreased, or the particle size distribution of a sludge widened. Conditioning, elutriation, supernatant removal, and replacement were found to reduce β by improving the mean particle size of a sludge and narrowing a sludge particle size distribution. In addition, β was found to increase by the applied pressure differential and filter media pore sizes for a few sludges. / Master of Science

Optimization techniques are used to investigate changes in structural design which increase the energy absorbing capabilities of a marine vessel in a collision. The structural model of the vessel includes the stiffened shell, web frame supports, and rigid bulkheads. The failure criterion used is hull rupture, appropriate for tanker design. The collision scenario is a right angle strike by a rigid vertical bow midway between two rigid bulkheads. The stiffened shell is modelled as a series of longitudinal beams in plastic bending and plastic membrane tension. Optimization parameters included both the number and dimensions of the transverse web frames and longitudinal beams. The technique was applied to the redesign of a large oil tanker. Minimizing the weight with a constraint on the energy was superior to maximizing the energy with a weight constraint in both computation time and performance. Optimization increased the volume of the shell beams while decreasing their moment-of-inertia. In addition the volume and strength of the frame were decreased precipitating early development of membrane tension in the shell and spreading of damage throughout the compartment. An reduced the number of web frames from optimum design six to two and increased the energy absorbed before rupture by 130%. Lesser collisions energies were found for more conservative designs which included a set number of web frames and restrictions of other design parameters. The use of high strength steel was also investigated. / M.S.

The possibility that visual thresholds fluctuate in a circadian rhythmic (twenty-four hour) pattern was examined. Subjects were tested at 0400h, 1000h, 1600h and 2200h in a 30 minute dark adaptation procedure using a von Békésy tracking method. Two experiments were performed; the first tested cone functions with a red 1 degree monochromatic test stimulus located ten degrees nasally. There were no sex differences for the ten male and female subjects used in this study. However, there were time of day differences with higher thresholds at 1000h than at any other time. The second experiment examined both rod and cone thresholds with a heterochromatic test stimulus. Sex differences were found 'for the 10 male and 10 female subjects. The rods for males were found to exhibit significantly higher thresholds at 1000h than any other time. There were no significant differences for females. The null results for females may be due to an influence of the menstrual cycle on vision. The rod differences for males is thought to occur because of rod outer segment shedding which also has a circadian rhythm. A circadian rhythm questionnaire was administered to the subjects and it was found that morningness and vigorousness related to visual thresholds. / Master of Science