An experimental investigation of highly underexpanded exhaust jets impinging in a direction normal to a curved surface was conducted in the NASA-Langley Research Center 55-foot vacuum cylinder. The investigation included measurements of impingement pressures and measurements of various normal shock characteristics. Variables of the investigation were the size of the jet, jet-exit Mach number, exhaust gas, distance of the jet from the impingement surface, curvature of the surface, and jet-exit to ambient pressure ratio. The experimental data are presented and compared with available theory. / Master of Science

Population density as high as 0.70 square foot per bird had no apparent effect on growth, feed conversion, mortality, and market quality on Medium White turkeys to 10 weeks of age. At 14 weeks of age body weight and feed conversion decreased slightly for both males and females allowed less than 0.85 square foot per bird. Market quality and mortality were unaffected for both sexes allowed less than 0.85 square foot per bird. It was noted that consideration had to be given to litter management when high density production methods were practiced because wet litter at decreased floor space levels may contribute to potential disease outbreaks and added cost of dry litter for replacement. Both males and females reared on range were significantly heavier at 18 and 22 weeks of age than those reared in confinement at two and three square feet per bird. Bird density of two square feet per bird in confinement did not adversely affect body weight or feed conversion from 14 to 22 weeks of age. Market quality and mortality were approximately equal for confinement and range reared turkeys. Economic returns above poult and feed cost were found to be approximately 13 and 25 cents higher per square foot of floor space for females and males respectively, when allowed 0.70 rather than 1.30 square foot per bird to 14 weeks of age. / Master of Science

This thesis presents an analytic solution for the stress distribution in a semi-infinite strip subjected to symmetrical loads on the transverse edge. Three different types of loading on the transverse edge are considered: (i) a segment of uniform load, (ii) two concentrated normal loads, and (iii) two concentrated tangential loads. The solution is constructed by the method of images. Under successive reflections the given strip and the resulting images become a semi-infinite plate with a series of periodic loads on the edge. The stress function for such a plate is constructed by superposing the known solutions of a simple nature. To satisfy the boundary conditions along the longitudinal edges of the semi-infinite strip, additional stress functions are introduced. When the boundary conditions are adjusted, a system of integral equations and a system of algebraic equations are obtained, which are further reduced. to a single system of algebraic equations. The latter system is solved by the method of successive approximations. In each case, the expressions for normal stresses along the longitudinal axis are derived and numerical values for these stresses are given. / Master of Science

A finite difference method of investigating the shock layer in the vicinity of the stagnation point in a two-dimensional supersonic flow past a circular cylinder is analyzed. This method differs from existing methods which have been used in the past for solving this type of problem in that it uses the properties along the stagnation streamline as initial conditions. However, the method can still be classified as one of the direct type. A potential flow solution along the stagnation streamline is used to approximate the initial conditions. The results are compared with existing solutions and available experimental data. / Master of Science

Parawing vehicles may have unusual values of many of the mass and aerodynamic factors affecting dynamic lateral stability and control. These unusual characteristics are due in large part to the fact that the center of gravity of parawing vehicles is located far below the parawing, whereas conventional aircraft usually have the vertical center-of-gravity location near the plane of the wings. The present thesis is an analytical investigation of the dynamic lateral stability and control of a typical parawing vehicle. The analysis was made using three-degree-of-freedom, rigid body equations of motion. Stability derivatives used in the calculations were obtained from static and dynamic force tests of a parawing model with rigid leading-edge and keel members. The analysis is treated mainly in terms of the effects of vertical center-of-gravity position, since this was found to be the most significant factor affecting the lateral stability and control of the hypothetical vehicle. / Master of Science

The enhancing effect of K on alfalfa (Medicago sativa L.) yield has frequently been reported, but the nature of this influence has not been clearly shown. It was assumed that K contributed either to increased leaf expansion, thereby resulting in a larger photosynthetic surface, or to higher CO₂ assimilation rates per unit leaf area. Sand culture technique for growing plants was used in two greenhouse experiments, while field plants were grown in plots with soil differing in available K. Yield increases were consistently obtained with high K. Added K increased plant height and leaves per plant and per plot, The rate of leaf accumulation was higher as K increased. Leaf size and weight per unit area also increased, as did stomatal number and aperture. Larger epidermal cells and greater numbers per leaf were observed with high K nutrition. Percent K in plants was associated with rate of K application. Net photosynthesis rates of excised leaves increased with potassium application, but all K levels had similar light compensation points. Leaves from plants with added K had lower CO₂ compensation points, indicating higher efficiency of CO₂ assimilation. Based on these data, K appears to function both to increase the effective photosynthetic surface through greater leaf initiation and development and to increase the rate of CO₂ utilization per unit leaf area. The latter increase probably results from greater CO₂ diffusion into substomatal cavities. / Ph. D.

This dissertation is a study of the composition dynamics of a bench size sieve-plate distillation column. The column was 2-3/4 inches in diameter, 30 inches in length, and contained 10 sieve-plates spaced 2-1/4 inches apart. A benzene-toluene mixture was used as the feed to the column. The pulse testing method for obtaining dynamic information was used. The column was upset by introducing a rectangular pulse increase in benzene composition in the feed stream. The response of each plate was measured in the form of temperature and was converted to a composition response. Frequency response curves were determined for each plate from the pulse response. For the frequency response analysis, the forcing function of a plate was considered to be a weighted sum of the compositions of the liquid and vapor streams entering the stage, while the output function was considered to be the liquid composition on the plate near the exit downcomer. The resulting frequency response was relatively flat in the frequency region of primary interest. The flatness of the frequency response was attributed to poor liquid mixing on tha plates. Based on the experimental observations, a plate in the column may be mathematically represented by a dead time and a steady-state gain. / Ph. D.

Six fungi, Pestalotiopsis westerdijkii QM:381, Myrothecium verrucaria QM:460, Aspergillus terrus QM:72f, Chaetomium globosum QM:459, Basidiomycetes sp. QM:806, Trichoderma viride QM:6a were screened according to their ability to elaborate an extracellular enzyme system which has the highest soy fiber-degrading activity and the highest carboxymethylcellulase activity. Pestalotiopsis westerdijkii QM:481 gave the most potent extracellular enzyme system. When Pestalotiopsis westerdijkii was grown on a wheat bran medium at a temperature of 31.5°C for ten days, it elaborated the most potent extracellular enzyme system. It was found that the optimum conditions for this extracellular enzyme system, acting on soy residue for the purpose of making soy residue protein available for extraction, were pH 4.6 and 38°C. Treating one gram of soy residue, 40 ml (32 mg Nitrogen) enzyme preparation, at the optimum pH and temperature for 20 hours caused the most efficient extraction of protein. There was an increase in the amount of soluble carbohydrates, reducing sugars, glucose and galactose due to the action of enzyme on soy residue. The amount of non-protein nitrogen in the extractable fraction of soy residue after treatment with enzyme preparation or water increase with the increase of incubation time even in the presence of toluene which prevents bacterial contamination. This is probably due to the action of proteases from the soybean and enzyme preparation. In large scale experiments, when 40 ml (32 mg Nitrogen) of the enzyme preparation per gram of soy residue were used, about 60% of the soy residue protein was made available for water extraction and the yield of extractable protein in soy milk was increased by 20%. Feeding experiments using treated or untreated soy residue and soy milk showed that the treated milk contains protein of higher quality and better digestibility when compared to untreated soy milk or treated residue. The most limiting amino acid in these products is methionine. The amino acid composition of these products was very much the same. / Ph. D.

This research is directed towards the minimization of the total cost of the single-item, single-source, deterministic inventory system in the face or multiple constraints. The Lagrangian multiplier technique is used for optimization. Two models, the general model and the special model, with multiple constraints are studied. For the special model the solution becomes indeterminate and/or incompatible whenever more than one constraint is active and the trial and error method is suggested for this situation. For the general model, the constraints are classified into two basic groups of incompatible constraints. Also, other possible groups of incompatible constraints are listed. A sample solution for one group, out of many possible groups, of compatible constraints is presented. Illustrative examples are given. / Master of Science

This thesis contains a brief review of some of the work that has been done concerning the generation and testing of pseudo-random numbers. Computer subroutine programs written in FORTRAN IV are given for the generation of pseudo-random numbers from Pearson distributions as well as from any combination of mixtures of two Pearson distributions, a normal distribution with arbitrary mean and variance and a uniform distribution on any finite interval. The Pearson distribution may be specified either by the first four moments or from sample data, then the parameters of the fitted distribution are printed and, if desired, a graph of the distribution. A graph of the mixture of distributions may be obtained from 10,000 pseudo-random numbers from the mixture. The speed of generation varies from about 10,000 random numbers per minute (on the IBM 7040), for a Pearson distribution with moments calculated from the generated numbers, to more than 100,000 numbers per minute if mixtures are used. The subroutines are applied to a Monte Carlo investigation of the robustness of several methods of confidence interval estimation. / M.S.