Four samples of cellulose acetates having degrees of combined acetic acid between 50.8 - 55.8% were fractionated to obtain sharp fractions or approximately the same degree of polymerization. About 2000 grams starting material of each sample of cellulose acetate were needed to obtain approximately 50 grams or sharp fraction for testing the mechanical properties of their films. Fractionation of the cellulose acetate was from an acetone-water mixture, by addition of n-heptane to precipitate a certain traction. After a series of refractionations, a sharp fraction of each of the four cellulose acetates was obtained. These fractions had different degrees of acetylation but approximately the same degrees of polymerization. These fractions were then dissolved in acetone and cast into films which were conditioned for three days and their mechanical properties were determined in an attempt to determine the effect of degree of acetylation on the mechanical properties. It was found that the degrees of acetylation of the various sharp tractions of cellulose acetates had no appreciable effect on the mechanical properties of their films. It was concluded that the degrees of polymerization of the various fractions were so high that the effect of the degree or acetylation on the mechanical properties could not be detected. The degrees of polymerization of the various samples were determined by the viscosity method using acetone and cupriethylenediamine as the solvents, It was found that the degrees of polymerization of the various samples of cellulose acetates determined by the cupriethylenediamine viscosity method were almost four times greater than the degrees of polymerization of the same samples determined by the acetone viscosity method using constants obtained from the literature. / Ph. D.

Experiments were undertaken to study in vivo the effect of hexachloronaphthalene in vitamin A metabolism in the rat. The status of vitamin A in the animal was determined by tissue analysis for the vitamin and by visual observation for symptoms of vitamin A deficiency. Four studies were made. The effects of dietary hexachloronaphthalene on preformed residual vitamin A, on assimilation of dietary carotene, on assimilation of a single oral dose of carotene, and on the absorption and storage of a single oral dose of vitamin A palmitate were investigated. In addition, the effect of ingested hexachloronaphthalene on calf plasma protein was studied. The following conclusions were derived from the results of the experiments. 1. The metabolism of dietary hexachloronaphthalene resulted in an increased requirement for vitamin A in peripheral tissue. This effect was apparently separate from the liver hypertrophy and fatty infiltration which are characteristic results of chlorinated naphthalene ingestion in rats. The mechanism of this increased demand for vitamin A was not discerned. Vitamin E supplementation was or no apparent value in preventing this increase in the requirement for vitamin A. 2. The addition of vitamin E to carotene-rich diets normally produces an increased yield of vitamin A. This stimulus of carotene conversion was not apparent when hexachloronaphthalene was included in the ration. 3. The ingestion of dietary hexachloronaphthalene depressed the ability of the rat to convert carotene to vitamin A. This was not true when the total dose of the toxic compound was included in the carotene solution. The addition of a bile salt to the carotene solution was not or value in preventing the depression of carotene conversion. Neither, however, did it stimulate conversion in the normal animals as was expected. 4. The ingestion of dietary hexachloronaphthalene had no apparent effect on the ability of the rat to absorb and store a single oral dose of vitamin A palmitate. 5. Paper electrophoresis studies and analysis of changes in TCA precipitable plasma protein in calves indicated that a depression of the level of the plasma proteins, especially the albumins, was a manifestation of the ingestion of hexachloronaphthalene by these animals. / Master of Science

In this study eighty farmers were interviewed. As far as the writer was able to determine, this number represented over fifty per cent of the farmers who received one-half or more of their income from the farm as cash or family food. If the number interviewed may be considered to constitute a valid study, several conclusions are formulated. / Master of Science

Numerous findings have indicated that the distance between the evaporator and condenser of the molecular still is not as critical, as far as mean free-path design criteria are concerned, as formerly believed. It had been recommended that studies be made on the present apparatus at Virginia Polytechnic Institute to determine exactly how critical this factor is. The purpose of this investigation was to study the effect of condenser temperature and location on the molecular distillation characteristics of stearic acid, and from this study, determine this relationship of condenser temperature and location to be used in centrifugal molecular still operation. This investigation was accomplished using a magnetically driven centrifugal molecular still with a five-inch rotor and employing the following operating conditions: operating pressure, 24 ± 2 microns of mercury, absolute; feed rate, 60 to 65 milliliters per minute; rotor speed, 1000 ± 50 revolutions per minute; feed-residue temperature differential, 24 ± 1 degrees centigrade; condenser water temperature, 25, 35, and 45 degrees centigrade; condenser locations, 3/4 2-1/2, and 5-3/8 inches from the evaporator; and number of passes of the feed over the rotor per fraction, one. lt was concluded from this investigation that if the Iocation of the condenser did not exceed a mean free-path multiple of three, that the location of the condenser had no effect on the elimination maximum of stearic acid, and the elimination maximum was increased approximately one degree centigrade for every four degrees centigrade decrease in condenser temperature. The elimination maximum was not affected by condenser temperature when the condenser was located in a position with a mean free path multiple of six. / Master of Science

Master of Science

One of the most challenging aspects of architectural practice is the design of residences. Because the solution appropriate for each situation differs with the composition, the cultural and ethnic background, and the living pattern of each family, the design of a home is never lacking in interest; because the family and its home are the basis of our civilization, residential architecture is of lasting significance. While within and about the home the individual comes under its influence, and his physical and emotional health are greatly affected. Physiologically he is affected by temperature, ventilation, humidity, and illumination; psychologically he is affected by crowding, clutter, noise, color, and spatial relationships. By deciding upon one design or another, the designer of homes, whether he is conscious of it or not, influences the future success and happiness of family life in the most intensive manner. Therefore, the architect has at his command a tremendous power of good or evil. Although definite progress in raising the standards of dwelling design has been made since World War II, there is still a great need for exploration in the field of house design, especially with regard to the technical and functional aspects of planning. The purpose of this thesis is to provide an opportunity for such general investigation and to apply the information thus gained to an actual, specific problem, the design of a residence for the author's parents. / Master of Science

Tests on hamsters reveal that there is a decided protective index from the soluble antigen prepared by the acid-heat extraction of living cultures of Leptospira pomona. They also reveal that the antigen must be given in quantities sufficiently small to be amenable to the system of the test animal or a condition of ”immunogenic paralysis“ results. Due to the number of hamsters in any one group whose pooled sera was tested, a fair evaluation could not be made between various groups in the agglutination-lysis test. Tests on the stability of the immunogenic agent used show that it is completely stable for at least a period of three months when stored in a refrigerator at 5 °C. / Master of Science

It was the purpose of this investigation to study the effect of varying the direct to reverse time ratio of periodically-reversed, direct current from 1.0 to 20.0 at an anode current density of 4.5 amperes per square centimeter, and to study the effect of alternating current of 60, 240, and 500 cycles per second, 0.2 to 4.5 amperes per square centimeter, superimposed on direct current on the electrolytic production of peroxydisulfuric acid. Electrolyses of 200 milliliters of sulfuric acid of specific gravity 1.4, at a temperature of 5 to 10 °C were performed with direct current. The anode current density was varied. The surface area of platinum anode and lead cathode was 2.0 and 221.8 square centimeters, respectively. For one hour of electrolysis, the yields were 7.9, 14.0, 20.2, and 22.9 grams of peroxydisulfuric acid at the anode current density of 1.5, 3.0, 4.5, and 6.0 amperes per square centimeter, respectively. The current efficiencies corresponding to these anode current densities were 85.0, 77.0, 61.5, and 53.4 per cent. The results showed that the yield was increased and the current efficiency was decreased with increase in the anode current density. Electrolysis of the same concentration and volume of sulfuric acid using periodically-reversed, direct current yielded 14.2 grams at an anode current density of 4.5 amperes per square centimeter and at a temperature of 5 to 8 °C. The time of electrolysis was one hour and the time ratio of direct to reverse electrolysis was 20. The current efficiency obtained under these conditions was 42.6 per cent. Decreasing the direct to reverse time ratio gave lower yields and current efficiencies. Apparently, there is no advantage in using periodically-reversed, direct current over the use of direct current for this reaction under the above experimental conditions. Electrolyses of 200 milliliters of sulfuric acid of the same concentration were performed with 60 cycles per second, alternating current superimposed on direct current. The direct current density was 4.5 amperes per square centimeter for the ten tests, but the surface area of the platinum anode was changed from two to one square centimeter and the direct current was decreased from 9.0 to 4.5 amperes. The current efficiency decreased sharply from 61.5 to approximately 31.0 per cent as the ratio of peak alternating to direct current increased from zero to 0.2 and then it remained constant until the ratio reached one. The current efficiency decreased suddenly to almost zero when the ratio was greater than one. The same sulfuric acid was electrolyzed under the same experimental conditions with 240 and 500 cycles per second, alternating current superimposed on direct current. Both direct and alternating anode current densities were varied. The direct current density was 2.2 and 4.5 amperes per square centimeter. The current efficiencies obtained during these tests were almost the same as that obtained with 60 cycles per second, alternating current within a specific limit of the ratio of peak alternating to direct current. The ratio of peak alternating current to direct current at which the current efficiencies suddenly dropped to zero was 0.75 for 240 cycles per second, and 0.5 for 500 cycles per second, instead of one for 60 cycles per second, superimposed alternating current. The platinum anode was activated and dissolved into the sulfuric acid when the ratio of peak alternating to direct current was greater than 1.0, 0.75, and 0.5 for 60, 240, and 500 cycles per second, alternating current superimposed on direct current. Apparently, there is no advantage in using alternating current superimposed on direct current over the use of direct current for electrolytic production of peroxydisulfuric acid. / Master of Science

This investigation was designed to secure data concerning the over-all effects of a high fox population on other game species, particularly the quail, rabbit, squirrel and ground-hog. In order to obtain a better understanding of the influence of the red fox upon other game species, some knowledge of the size of the populations of other game animals must be known. For this reason, a rather intensive study of the fox was made on the 2300- acre V.P.I. College Farms as some data were available on this area regarding the population and population changes in the quail, rabbit, squirrel and woodchuck. The study was carried on from April, 1950, to March, 1952. An extremely high fox population existed on the area during the period covered by the investigation (April, 1950, through March, 1952), so it was natural for the study to be carried on here. It is hoped that this investigation will point out some of the ecological factors which must be considered in determining a sound wildlife program for the management of the red fox and other game species on the same areas. / M.S.

M.S.