No description available.

M.S.

The report of the Baruch Committee on the rubber situation included a recommendation for a production of 60,000 ton per year production of Thiokol by the end of 1943. Thiokol is a type of synthetic rubber formed by the reaction between organic dihalides and inorganic polysulfides. They find wide application where resistance to petroleum oils, organic solvents, and low permeability. The purpose of this investigation was to design a Thiokol with a production of 2000 tons per year. Research was conducted to determine operating conditions for the production of sodium polysulfide, one of the raw materials for the production of Thiokol, and conditions for the Thiokol production. The information for the design of the ethylene dichloride, the other raw material of Thiokol, was obtained from literature. The studies of the polysulfide solution showed that 13.83 grams of sulfur would react with every 10. 2 grams of caustic when sulfur was in excess. The amount of sulfur that reacted was independent of the amount of excess sulfur. Other studies indicated that a dilution of 100 cc. of water per 10.2 grams of caustic was desirable, and that a period of 12 minutes of boiling gave the highest polysulfide content. Further time of boiling was not deleterious, but neither did the amount of sulfur as polysulfide increase. A complete sulfur analysis of the polysulfide solution showed a polysulfide content approximately 3.2 times that of the monosulfide indicating higher polysulfides than tetrasulfide being formed. Experiments conducted with the polysulfide solution as prepared and using just ethylene dichloride gave unsatisfactory results, although products obtained using lower temperatures were slightly better than those with higher temperatures. Magnesium chloride was unsatisfactory as a dispersing agent using the polysulfide as prepared, but ethyl alcohol gave satisfactory results. Studies of dilution yielded products of high values ranging from 91 to 75. Large amounts of freshly precipitated were satisfactory as dispersing agents but with small amounts the value of the product was 60. The highest valued product obtained was with 5 cc. of ethyl alcohol and dilution, but a satisfactory product, value 85, was obtained with one gram of magnesium chloride and dilution. Since the latter was more economical, these conditions were selected for the design of the Thiokol plant. Preconstruction cost accounting of the designed plant indicate an annual cost of $610,087 per year and a surplus of $589, 912 per year. This is based on a selling price of $0.30 per pound for Thiokol. / M.S.

M.S.

M.S.

A literature review of rubber-bearing plants in the United States was made, and the essentials of distribution, ecology and rubber content presented in condensed form. Filed lettuce of the specie Lactuca scariola was investigated to determine its place among the other rubber-bearing plants. Nearly pure stands of natural growing wild lettuce were harvested and the weights of plant material determined. Yields up to 2,830 pounds of dry leaves together with 5,760 pounds of dry stems per acre were obtained. The seasonal variation in rubber content and resins of one natural growing wild lettuce stand was studied from the time of the appearance of flower buds to the end of the growth cycle. At this time of maximum rubber content of this stand the calculated yield was between 1.16 and 1.57 pounds of rubber per acre. An experimental planting was undertaken to determine rubber content, resin content, and growth and cultivation characteristics of the earlier stages of growth. Young plants gave up to 0.339 percent rubber and a calculated yield of 13.7 pounds of rubber per acre. Drying temperatures up to the 180°F gave no decreases in rubber content during drying. The rubber content of harvested plants was found to decrease rapidly on exposure to sunlight. At least 10.7 percent of the seeds were found to have the power of germinating soon after ripening. Seeds ripened in the fall were found to have between 49 and 68 percent germinating power. / Master of Science

no abstract provided by author / Master of Science

M.S.

Two groups of cows were fed a ration in which three pounds of a grain mixture was used to every four pounds of hay. Two cows (Test Tube and Deborah) were fed Timothy hay with a grain mixture containing yellow corn. The other three cows (Dolly, Connie and Dot) were fed Alfalfa hay with a grain mixture containing white corn. The grain was also modified for protein balance. Relationships of carotene and Vitamin A concentrations in the blood, milk and feed were then studied. An attempt was made to correlate the various factors involved, the variables being: period of gestation; time after calving; intake of the vitamin and its precursor in the feed; milk produced; percent of the concentration of Vitamin A activity of blood and milk represented by carotene; total Vitamin A activity of the same; and, the efficiency of the secretion in the milk of the Vitamin A activity of the feed ration. The methods of determination of the carotene and Vitamin A (together constituting the Vitamin A activity) are given with details of the calculations. Milk was collected on the first, third and fifth day after calving and at approximately monthly intervals thereafter. Having begun the experiment with the cows in various stages of gestation, it was possible to obtain only six samples from Dot while ten were collected from others. The blood samples also were taken monthly. The feeds were analyzed at three monthly intervals and the rate of loss of Vitamin A activity observed. Minimum values were used in all calculations. / M.S.

A brief investigation was made of various organic and inorganic solvents for the dissolution of urinary calculi in vitro and Albright’s (1) citric acid buffer and a solvent designated in this investigation simply as “G” (33) were shown to be the most efficient solvents. Further investigation showed that something was necessary to increase the efficiency of these solvents, as the dissolution would proceed to a certain point where the solvent ceased to act. It was at this point that the investigation changed its course and the attack was centered on the organic colloidal matrix in the structure of the stone. It is a well known fact that this organic matrix is resistant to weak acids and bases (30) and therefore the course of the investigation pointed to those most remarkable agents, “the enzymes”, which due to their enormous amount of surface energy are capable of producing astonishing results. The enzymes investigated were not selected for their specific action, but they were selected for the purpose of studying the effect of their surface energy on the colloidal matrix of urinary calculi. The investigation indicates that a calculus pretreated with urease for fifteen minutes, followed by a 6 hour irrigation with “G” (33) solution is sufficient to cause dissolution and disintegration in nearly all of the one hundred calculi selected at random. (See Table 5) The ability of urease to hasten disintegration may be due to its activity on the colloidal matrix, causing it to swell, thereby giving back the former hydrotropic properties mentioned by Snapper (52). Colloidal material was isolated from a large calculus and was subjected to the action of urease. After 6 hours the colloids from the calculus had swollen approximately five hundred times their original volume, and changed from a dark brown-colored material to a white translucent gel. These organic colloidal matrices of urinary calculi are apparently of a reversible nature and irreversible as investigators have assumed in the past (30). Investigations were made and reported in various sections of this paper on the ability of other enzymes, peroxide, and acids to act as dissolution agents or as aids to dissolution. An efficient in vitro irrigator Fig. 1 is described and its merit in the irrigation of urinary calculi lies in the facts that its construction is simple, its rate of flow can be accurately regulated by a slight manipulation, and the calculus can be treated in various ways without removing it from the original crucible. It now remains for the urologist to investigate the possibility of in vitro dissolution, using the above auxiliary agent. It is suggested that the urease might be used simultaneously with the irrigation solvent. / Ph. D.