A total expected cost model for multivariate acceptance sampling is developed. The components of cost included in the model are presented in two phases: the cost of making the quality control decision (sampling inspection) and the cost of implementing the quality control decision (accept the inspection lot, scrap the lot, or screen the lot). Several variables are to be controlled within their given specification limits, where the sample mean for each of the variables in the criterion by which lot acceptance for that variable is determined. The decision variables are the sample size and the lower and upper control limits for each of the characteristics subjected to the control. The pattern search is used to determine the values of the decision variables which minimize the total expected cost of quality control per inspection lot submitted for control. The lot mean, sample mean, and individual unit measurements for each of the quality characteristics are considered to be random variables. Sensitivity analysis is performed to determine the robustness of the model to changes in the form of the distributions on the lot means given that the desired mean and variance of these distributions has been accurately estimated. / Master of Science

The rapid deterioration of the water quality in the upper end of the Roanoke River arm of Smith Mountain Lake has caused much concern. Eutrophic conditions have been established in this portion of the lake since 1965, when it was first brought to operating level. A multiphase productivity study was conducted on Smith Mountain Lake and lower Leesville Lake during July, August and September of 1971. Parameters monitored in this study included oxygen, temperature, algae, bacteria, specific conductance, light and primary productivity. The effect of each of these parameters on the trophic levels in the reservoirs was studied. The results of this investigation showed that the inflow of the nutrient rich Roanoke River had caused eutrophic conditions to develop on the upper reaches of Smith Mountain Lake. High suspended solids levels had greatly reduced light penetration, causing productivity to be limited in the uppermost portions of the lake. Evaluation of the productivity potential of the hypolimnion of Smith Mountain Lake indicated that destratification would be detrimental to water quality. Stratification in Smith Mountain Lake was only slightly affected by the pump-back from lower Leesville Lake. Equations were developed in this study for predicting the level of productivity from light extinction coefficients. These equations showed good correlation with observed levels of productivity in the lower half of Smith Mountain Lake. / Master of Science

The in vivo effects of triiodothyronine on the synthesis of hepatic purine nucleotides was investigated in sulfaguanidine-fed hypothyroid rats. To prevent the rapid destruction of nucleotides caused by anoxia and ischemia an apparatus was designed to maintain ether anesthesia while providing normal levels of oxygen. Liver samples were obtained from anesthetized rats by freezing in situ. Administration of 15 µg of triiodothyronine to hypothyroid rats weighing 110-120 g resulted in stimulation of the incorporation of [1-¹⁴C]glycine into the total soluble adenine and guanine nucleotide pools as early as l hour following injection. The increase in the specific activity of adenine was greater than that of guanine for up to 4 hours. No increases were detected in the levels of total adenine or guanine. Hormone treatment stimulated the rate of incorporation of glycine into AMP and NAD⁺ within 1.5 hours. The magnitude of the observed increases in specific activity of AMP and NAD⁺ were dependent upon the relative timing of administration of hormone and glycine. The greatest increase in specific activity was observed in NAD⁺. The effect of the hormone on the synthesis of GMP was variable and dependent upon relative timing of administration of hormone and glycine. At the shortest times studied there was no apparent effect of the hormone on the specific activity of GMP. At longer times of hormone treatment a moderate decrease in specific activity was observed in the GMP. Treatment of rats with actinomycin D prior to hormone injection did not prevent the stimulation of synthesis due to triiodothyronine. Actinomycin D alone stimulated the incorporation of the precursor into the soluble nucleotides and magnified the effects of the hormone in increasing the specific activities of AMP and NAD⁺. / Master of Science

To determine the relationship between conceptual development and performance on reversal learning tasks in children, a three part experiment was conducted employing 45 preschool, 45 kindergarten and 45 second grade children. During part one, all 135 subjects were taught the initial learning phase of the Kendler’s (1962) reversal shift task. When initial learning criterion was met, subjects from each age group were divided into 3 subgroups of 15 subjects each. The first subgroup was given conceptual training on an analytic task described by Kagan, Moss and Sigel (1963). The second subgroup was given conceptual training on a nonanalytic task (also described by Kagan et. al., 1963) and the third subgroup served as a control group by receiving no conceptual training. Once training criterion was met, all subjects were given a reversal shift task. Three significant trends were found: (1) with increasing age, reversal performance improved, (2) kindergarten children were more nonanalytic in their response preference than either preschool or second grade children and (3) while both types of training resulted in enhanced reversal performance, analytic training was more useful than nonanalytic training in facilitating reversal learning. Two separate phenomena are suggested by these results. First, preschool and kindergarten children appear to make discriminations on the basis of dimensional preferences while second grade children are able to discriminate on the basis of analytic reasoning. Second, for those subjects unable to verbally mediate, training appears to help them focus their attention on the relevant dimensions of the discrimination task. / Master of Science

A computer simulation model of the relationship between education, health, and income was developed for a low-income area of Miami, Florida. A basic assumption was that a causal, circular relationship exists among these factors and that change in one will give rise to an accumulative advance in the others. The estimates obtained from the model were for the ten year period 1960-1970. They confirmed the general absence of change in the study area. The education, health, and income components remained at or near original levels. Using these estimates as a datum, modifications were then introduced into certain model variables to simulate the effect of an improved transit system. With the exception of health, which did seem to be noticeably affected by transit service, the general pattern of the study area remained unchanged. The conclusions of this research were that: 1. Low-equilibrium systems, such as the urban ghetto, have substantial inertia in their social processes. This inerti~ minimizes the effects of social and economic change. 2. Change, to be effective, must concentrate on strategic system variables and must be of large magnitude and occur over a long period. 3. The circular connectivity of processes in ghetto systems is not strong. As a result, a cumulative upward charge in the ghetto is difficult to achieve. 4. Transportation does not appear to be an important catalyst to system change. / Master of Urban and Regional Planning

In an attempt to provide a consistently high quality product to the consumer, the apple industry is currently considering making condition a part of grade. Information concerning apple movement at the retail level is needed to help determine where such standards should be set. To provide such information, a study of six stores located in Southwest Virginia was undertaken to determine how long apples remain in retail displays under current marketing practices. Observations were also made on marketing practices which affected the quality of fruit reaching the consumer. Each store was studied for a minimum two week period. Current stocks and incoming lots were color coded and counted each day to determine the length of time apples remained on the retail shelf. Samples were taken of lots when they entered the store and after they had been on display. An oral interview was conducted with each of the produce managers. The results indicate that 95 percent of bagged, loose, and overwrapped apples were sold within 7, 9, and 12 days respectively. Sales of bagged apples were 4 times that of overwraps and loose combined. The results of the produce managers' interviews indicated that they are usually satisified with the product they are receiving. The study indicates that the required shelf life of apples could be reduced through improved merchandising practices. The quality of apples reaching the consumer could be improved by making condition part of grade. / Master of Science

A model of the inter- and intra-seasonal energy flow through deer populations ,.;as developed through the use of the existing literature. The model was programmed in Fortran IV for computer based use in evaluating the potential biological productivity of land for deer. The model was developed specifically for evaluating land being considered for acquisition for deer-management areas. The model uses "Standard Deer Units" (an integration of climatic, behavior, and range characteristics affecting the energy dynamics of the deer) as a measure of the energy available for the production and maintenance of deer. Estimation of successional changes in cover and forage production are made by use of a flexible statistical distribution model known as a \.Jeibull distribution. Indices of the potential sightable and harvestable deer production are calculated in standard deer units at 5-year intervals over a 50-year planning horizon. / Master of Science

Studies over a two-year period were undertaken to evaluate the potential and effect of Rhinocyllus conicus as a biological control agent for Carduus nutans and C. acanthoides in Virginia. Over an 81 day range, 25 females oviposited an average of 100.5 eggs. Life expectancy did not differ between sexes. Examination of 1999 C. nutans plants in Pulaski Co. showed: 26.7% of all blooms were infested (46.7% terminals and 18.2% laterals); no weevil orientation relative to plant density but a preference for terminal blooms and no bloom size preference for oviposition. Evaluation of 261 capitula revealed that an infested bloom produced 37 mature seeds/mm of diameter. Each larva destroyed 9.7 achenes. Weevil mortality on C. nutans capitula occurred primarily during the egg stage (58.3%). Mechanical egg dislodgement was not a major mortality factor. Ege and/or adult parasitism was not observed. Aliolus curculionis, Bracon mellitor, and Campoplex polychrosidis parasitized the weevil larvae and pupae. Twelve other possible parasites were collected. Crowding was not a significant mortality factor. An egg maturation of 31.9% was noted, and 3.1 weevils emerged per infested bloom. Mortality among sites ranged from 56.1% (adjacent to trees) to 95.8% (unprotected). Weevil adults exhibited thigmotaxis by overwintering in the cracks of the framework of a large outdoor rearing cage. They apparently preferred this site rather than soil litter and debris. Best release establishment and dispersal occurred on C. nutans which was preferred to Carduus acanthoides. / Master of Science

One of the most critical urban problems is the ever-increasing demand for transportation facilities. An alternative for reducing the degree of peak-hour congestion is to increase the passenger movement capability of a facility by providing exclusive bus lanes. The Shirley Highway Express-Bus-on-Freeway Demonstration Project was implemented to test the hypothesis that the provision of rapid and convenient bus service over an exclusive lane would attract significant numbers of automobile passengers. Such a diversion would improve the passenqer movement and relieve the congestion of the facility, thus, resulting in an improved level of service for all travelers. This study was an evaluation of the project, and the main objectives were: 1. Determine the effects of the busway on bus patronage and automobile travel. 2. Analyze the sources of bus patrons and determine the reduction in automobiles. 3. Use the automobile reduction in comparing the level of service for the existing facility to the freeway without the exclusive busway~ In approaching these objectives, the study identified and evaluated such parameters as travel times, passenger and vehicular volumes, commuter profiles, and occupancy rates. Speed-volume-capacity relationships were used to compare the quality of service on the existing facility to a hypothetical roadway without an operational busway. The analysis revealed a large increase in bus patronage and a reduction in automobiles and congestion on the Shirley Highway. The existing facility was providing acceptable service, while the demand on the hypothetical roadway exceeded the capacity. / Master of Science

The removal of nitrate nitrogen from a munitions waste by means of bacterial reduction was investigated using packed anaerobic columns. The feasibility of using a munitions waste high in organic carbon (Water Dry Process Waste) as the organic carbon source was also investigated. Simultaneously the biological processing was accomplished in two manners, anaerobic packed columns and batch anaerobic vessels. It was found that anaerobic columns were effective in reducing 100 mg/l nitrate nitrogen by as much as 99.9% operating at an empty column detention time of 8.76 hours. No difference in denitrification capacity was found between columns packed with activated carbon or sand, but the activated carbon was found to be an undesirable media because of its low specific gravity which permitted it to float after gasification began, and because of foul-smelling odors associated with the activated carbon effluent. The Water Dry Process Waste was found to be a suitable organic carbon source for denitrification and it had a consumptive ratio of 1.47. Batch vessels were found to be ineffective in significantly reducing total nitrogen over a period of 46 days. Buildup of high concentrations of nitrite within the vessels suggested inhibition of the biomass to an extent that further denitrification would not occur. / Master of Science