A logarithmic spiral trajectory is not the optimum trajectory for a solar sailing space vehicle. Investigation of the governing equations showed that the performance of the solar sail depends on one parameter "a". This parameter "a", defined simply as the ratio of radial to tangential forces, was seen to be significant for two reasons: first, the logarithmic spiral is restricted to values of a = 2 √ 2 ; secondly, decreased values of "a" indicate better performance characteristics. For values of a < 2 √ 2 a new trajectory was generated and found to be more efficient than any logarithmic spiral trajectory. / Master of Science

The basic objectives of this study are (1) the identification of planning needs, (2) the development of an orderly approach to the processes of planning, and (3) the development of an argument for planning in rural counties of Virginia. The data was obtained through library research, personal interview, and field inspection in rural counties of Virginia. The most significant results are: 1. Current population trends show both compositional and quantitative changes taking place in the rural counties of Virginia. 2. Land use development patterns in Virginia rural counties, under the present conditions, are wasteful and overtax the existing facilities. 3. Land usefulness determinations involving soil composition and physical characteristics are gaining in use in agriculture, engineering, building, and taxation. 4. County government, although organized in its most prevalent form for antiquatedness and obsolescence, is adequate to make gainful use of the processes of planning, including the most up-to-date ideas. 5. Legislation is adequate at the state level to enable the county unit of government to implement by ordinances the policies appropriate to a rural county planning program. 6. Economic conditions in the rural counties are important indices to the soundness of the county's Condition. 7. Implementation of planning programs in the rural counties can be accomplished through action programs involving citizen participation as part of a continuous planning and educational process. / Master of Science

In this thesis, confidence bounds on simple and more complex parameters are stated along with detailed computational procedures for finding these confidence bounds from the given data. Confidence bounds on the more familiar parameters, i.e., μ, ơ², μ₁ - μ₂, and ơ²₁/ơ²₂, are briefly presented for the sake of completeness. The confidence statements for the less familiar parameters and combinations of parameters are treated in more detail. In the cases of the non-centrality parameters of the non-central t², F and X² distributions, a variance-stabilizing transformation is used, a normal approximation is utilized, and confidence bounds are pub on the parameter. In the non-central t² and non-central F distributions iterative procedures are used to obtain confidence bounds on the non-centrality parameter, i.e., a first guess is made which is improved until the desired accuracy is obtained This procedure is unnecessary in the non-central X² distribution, since the expressions for the upper and lower limits can be reduced to closed form. Computational procedures and completely worked examples are included. / Master of Science

This study is concerned with the desirability and feasibility of a well-planned industrial testing program which will improve a company's over-all efficiency by improving the skill, knowledge, and attitude of the employees. A careful study has been made of the material already published and available on the subject of testing programs, consisting of a historical background of training, consideration of the use of testing as a personnel device, and a detailed discussion of the various types of tests and testing programs. Case studies have been made of several selected industries and personal interviews made with management and personnel officials to determine their attitudes toward testing. An evaluation has been made as to the justification of testing programs, pointing out some of their weaknesses and suggesting possible solutions. / Master of Science

The distinction between the magnetohydrodynamic generator and the conventional wire-wound generator is that the role of the armature in the letter is played by an electrically conducting fluid in the former. This fluid is passed through a transverse electric and magnetic field and between two parallel plate electrodes. The induced electric field in the fluid, which is proportional to the fluid velocity and magnetic flux density, maintains a voltage drop across the electrodes and a current is generated when the electrodes are connected to an external load, closing the circuit. Thus energy is extracted from the fluid and delivered to an external load as electrical power. / Master of Science

The problem of determining the stability of a set of linear differential equations has been of interest to mathematicians and engineers for a considerable length of time. The problem is attacked by obtaining the characteristic equation of the original set of equations and determining the stability of this equation. The stability of the characteristic equation is first considered in terms of a continued fraction expansion. Necessary and sufficient conditions are given for the characteristic equation to be stable. The stability of the equation is then determined by means of a determinant sequence, which was the manner originally presented by A. Hurwitz in 1895. The Nyquist criterion, which is a graphical method for determining whether the equation is stable, is then presented. An example is given for each of the above methods to illustrate the procedure used in determining whether the equation is stable or unstable. Also included is a brief analysis of stability for non-linear equations. / Master of Science

Artificial and natural weathering studies were conducted on four dioctahedral micas found in soil parent material of the Virginia Piedmont. Emphasis was given to the relationship between loss of K (also Na in certain cases), increase in CEC, and expansion characteristics. Boiling treatments with several different solutions were used to promote artificial weathering. In terms of the three parameters of primary interest, the results were of three general types, depending upon the nature of the boiling medium. Boiling solutions of HCl and HOAc removed K and Na, but produced only slight expansion and a negligible increase in CEC. The acid solutions, being at low pH, liberated from the mineral large amounts of Al, which likely underwent hydrolysis later to form hydroxy-Al polymeric groups. These groups can occupy exchange sites, but they remain nonexchangeable. Boiling aalt solutions of NaCl and MgCl₂ removed K and Na in large amounts, produced considerable, but only a slight increase in CEC resulted. The explanation for the small increase in CEC was believed to be due also to blocking of exchange sites by nonexchangeable hydroxy-Al groups, because salts tend to accelerate the hydrolysis reaction. A boiling Na-citrate solution removed K effectively, produced marked expansion, and caused a large increase in CEC. Citrate complexes Al, which probably accounted for the high CEC. When a sample was treated with hot HCl prior to Na-citrate boiling, the loss of K and increase in CEC was stoichiometric. The equivalence was attributed to the removal of amorphous material by HCl and complexing of Al by Na-citrate. Vermiculite and kaolinite were the natural weathering products of the dioctahedral micas studies. There was a striking similarity between the artificially-produced vermiculite and that occurring under natural conditions. The product formed under both circumstances expanded to approximate 14 A. when glycerol-solvated and contracted to 10 A. upon K-saturation and heating. Although the artificial weathering media were not representative of natural weathering conditions, the basic mechanism of mica alteration apparently was similar. The soil micas altered easily in the laboratory compared to an Ontario muscovite. Thus, it was concluded that soil micas are quite different from the specimen-type micas. They may possess a lower charge or lack the structural control of specimen muscovites. The difference in ease of weathers between dioctahedral and trioctahedral micas likely is attributable to the difference in chemical composition, especially in the octahedral layer. Dioctahedral micas appear to be more strongly bonded than trioctahedral micas as a result of the higher-charged Al⁺⁺⁺ ion in the octahedral layer. This stronger bonding would tend to restrict initial alteration. Subsequent alteration also would be hindered because, as weathering proceeds, greater hydrolysis of Al in dioctahedral micas would result in more fixation of positively-charged hydroxy-Al polymers in the interlayer position. This fixed Al inhibits expansion of dioctahedral micas. In trioctahedral micas, which contain Fe and/or Mg, this type of fixation does not occur during acidic weathering. A significant finding was the occurrence of paragonite, the Na analogue of muscovite, in intimate association with muscovite. A relatively constant Na/K molar ratio of approximately one was maintained in both the parent rocks and soils. This indicated that equal molar quantities of paragonite and muscovite were present and that weathering of the two micas was similar. Paragonite is believed to be more widespread occurrence than previous work has indicated. Its influence on soil genesis, morphology, and classification may be significant. / Ph. D.

This thesis presents an experimental study of creep and shrinkage of concrete made from local limestone aggregate and type III cement. The cylindrical test specimens were exposed to the atmosphere in order to observe the effects that variations of temperature and relative humidity had upon creep and shrinkage. These effects are shown by graphical presentations in the thesis. Creep strains for the five month period of investigation are shown graphically for each of four conditions of stress, 1000 psi constant stress 1000 psi variable stress 500 psi constant stress, and 500 psi variable stress. Exponential equations for these surveys were derived from the creep data of the five month study. Ultimate creep values were predicted from these equations and are presented together with their respective creep coefficients. These values are given to represent the anticipated creep for limestone aggregate concrete subjected to field conditions. / Master of Science

When rennet type cottage curd was made from cheese milk pasteurized at 143°F. for 30 min. the heat labile serum proteins remained with the whey and represented a loss of approximately 15% of the total cheese milk protein. However, when higher heat treatments than pasteurization were applied, up to 65% of the serum proteins of cheese milk were denatured, rendered coagulable with the caseins and incorporated into the cottage curd. Similar results were obtained by blending high- and low- heat cheese milk. Composition and flavor quality of cards containing increased amounts of serum protein were closely comparable to curds made from conventional pasteurized cheese milk. The yield of curd was increased. As the heat treatment of cheese milk was increased from 143 to 180°F., the denaturation of serum protein in drained whey increased from 0.0 to 60.01%, the percent of whey solids decreased 7.1%, pH at the A-C endpoint increased from 4.72 to 5.10, and time from setting to cutting decreased from 4.75 to 2.50 hr. When the percent of high-heat milk in blended cheese milks was increased from 20 to 95%, the percent of denatured serum protein in drained whey increased from 4.8 to 37.2%, the percent of whey solids decreased from 1.1 to 5.3%. pH at the A-C endpoint increased from 4.70 to 5.05, and time from setting to cutting decreased from 5.50 to 2.50 hr. High quality curd comparable to the control was made from cheese milks receiving heat treatments up to 170° F. for 30 min. and from blonde containing up to 95% high·heat milk. Heat treatments over 170°F. slightly lowered the quality score of curd. Pounds of curd per lb. of cheese milk protein was found to be the best procedure for calculating and expressing yield. When curd was made from cheese milk heated at 170°F. and from blends containing 85% high·heat milk, the curd yield was increased 16.22 and 9.61% above the control, respectively. / Master of Science

The object of this thesis was to investigate some of the factors that night effect the oil film performance between piston rings and cylinder walls. An apparatus was constructed to measure the instantaneous changes in resistance across the oil film. A piston ring of an air-cooled single cylinder engine was insulated from the rest of the piston using Teflon. A bridge circuit was used to feed the unbalanced signals to an oscilloscope. The traces on the oscilloscope were recorded by means of an Polaroid-Land recording camera. An external motor having a speed control system was used to drive the engine. It was found from this investigation that the lubrication could be improved by increasing the engine speed and oil viscosity. More metallic contact was found when the engine was under its own power. The results also showed that the breakdown of oil film occurred when the oil temperature was increased. The experimental results indicated that the piston ring and the cylinder wall were never separated by lubricating oil at dead centers. The breakdown of oil film occurred at these positions in every case. / Master of Science