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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
271

Architecture in Eden: a transition between urban and rural conditions

Oziemblowsky, Richard January 1984 (has links)
This project examines the relationship between urban and rural conditions that exist in Alexandria, Virginia. The architect has drawn heavily from an editorial for <u>OPPOSITIONS</u> magazine entitled “The Third Typology”, by Anthony Vidler. “The Third Typology” is not utilized as a paradigm for architectural design, but rather as a validation of the ideologies employed. / Master of Architecture
272

Multipass effects of wheel and track type vehicles on soil compaction

Minaei, Saeid January 1984 (has links)
A field study was conducted in the fall of 1982 to investigate the effect of vehicle type, traffic moisture level, and their interactions on soil compaction. During the study two procedures commonly used for soil bulk density determination were also compared. Treatments at the following levels were applied: i) Soil moisture: Two levels ii) Vehicle type: wheel and track type iii) Traffic intensity: 0, 1, 3, and 9 passes. Each treatment combination was replicated three times and these were installed in random order on 48, 6 x 30 m test plots. Soil samples were taken at three locations from each test plot for the determination of moisture level. Core samples were taken in and outside the rut at three locations along each track for bulk density determination. Bulk density data using a double probe nuclear densitometer were taken at one location along the track. Statistical analysis of the data indicated that, of the factors considered in the study, number of vehicle passes and interactions between moisture level and vehicle type and number of passes and vehicle type had a significant effect on the compaction of the top soil layer. The two methods for measuring soil density were compared using the paired student's t-test and an equation was developed relating the density values obtained by nuclear and gravimetric procedures. Comparison of the data from the two methods indicated that the nuclear densitometer underestimated the core bulk density. / Master of Science
273

Immunotherapeutic alteration of tumor-induced suppression of interleukin 2 and 3 production by Propionibacterium acnes vaccination

Roberson, Alice Marie January 1984 (has links)
Previous reports indicate that anti-tumor activity arising from systemically injected P. acnes is macrophage-mediated, whereas anti-tumor activity arising from locally injected P. acnes is T cell-mediated. It is possible these P. acnes-induced cytotoxic T cells arise via the Interleukin cascade. Therefore, this study investigated the involvement of Interleukin 2 (IL 2) and Interleukin 3 (IL 3), known components of the Interleukin cascade, in local P. acnes-mediated anti-tumor action. A 500 ug dose of heat-killed stationary phase P. acnes given simultaneously with 10⁴ tumor cells was found to inhibit tumor formation completely, therefore this amount was used as a standard dose throughout the study. Unvaccinated counterparts developed palpable tumors two weeks after tumor cell administration. Lower doses of vaccine protected animals from tumor growth to a lesser degree. A vaccine prepared from logarithmic phase P. acnes exerted a moderate anti-tumor effect in some cases. IL 2 and IL 3 levels were measured in vitro in normal BALB/c mice (N), tumor-bearing mice (TBH), normal vaccinated mice (N+V), and mice receiving both tumor cell and vaccine injection (T+V). IL 2 and IL 3 production was maintained in both N and N+V host splenocyte cultures throughout the study. In a similar fashion, levels of IL 2 and IL 3 in T+V host splenocyte cultures were comparable to those of N+V hosts. However, TBH splenocyte production of IL 2 and IL 3 began to decline when tumors became palpable, at Day 14 after tumor cell inoculation. By Day 28, TBH IL 2 and IL 3 levels were <15% of normal control levels. Causes for this suppression of IL 2 and IL 3 production in TBH were examined. From reports of others it appeared that suppression may be mediated through prostaglandin(s). Addition of the prostaglandin inhibitor indomethacin to splenocyte cultures greatly enhanced IL 2 production by N, N+V and T+V splenocytes, but failed to restore IL 2 production in TBH splenocyte cultures to normal levels. Thus, it appeared prostaglandins were not directly responsible for the majority of suppression seen in TBH. In the non-tumor-burdened host, prostaglandin appeared to play a homeostatic role regarding IL 2 production. Indomethacin-treatment had little effect on IL 3 production. Nylon wool fractionation of N, TBH, N+V and T+V splenocytes suggested a cell removed by nylon wool treatment was largely responsible for the suppression of IL 2 and IL 3 production in TBH. No obvious presence of functional suppressor cells was noted in N, N+V or T+V splenocytes. From these results, it appeared that P. acnes administration maintains and/or restores IL 2 and IL 3 production, thus favoring the production of CTL. In addition, the suppression of IL 2 and IL 3 production seen in TBH may be due to a nylon wool adherent suppressor cell. A model describing the effect of P. acnes administration on local anti-tumor activity was presented. / Master of Science
274

The effects of acetone shock loading on phenol acclimated cultures

Reynolds, Larry Robert January 1984 (has links)
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
275

Application of software quality metrics to a relational data base system

Reddy, Geereddy R. January 1984 (has links)
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
276

Pennsylvania Station: a system of reuse

Ruppel, Barbara Spillers January 1984 (has links)
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
277

A theoretical model of the cornea as a thin shell of variable thickness in relation to radial keratotomy

Williams, Sharon Lee January 1984 (has links)
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
278

The effect of an aerobic exercise program and two hypocaloric diets of different carbohydrate content on blood pressure and sodium balance in obese females

Ruiz, Karina January 1984 (has links)
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.
279

Estimation of spacecraft attitude in the presence of unmodeled disturbance torques

Pinson, Earl Douglas January 1984 (has links)
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
280

The milk supply response of Virginia dairy farmers

Rao, R. Narain January 1984 (has links)
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.

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