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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.
11

The design of a thiokol plant

Petrey, Robert C. January 1943 (has links)
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.
12

A multi-attribute layout design problem

Mishra, Prateer January 1992 (has links)
Plant layout procedures available today consider either the quantitative attribute or the qualitative attribute of the layout problem. These procedures are based on maximizing or minimizing one objective function. Some of the procedures that address the multi-attribute nature of the plant layout problem are based on assigning weights to objective functions and then solving the problem by heuristic methods. Exact methods guarantee optimal solution but are computationally intensive for large sized problems. Heuristic methods do not guarantee optimal solution, but are computationally less intensive and relatively faster than the exact methods. This thesis suggests a procedure for solving the multi-attribute plant layout problem. The procedure is based on formulating the plant layout problem as a Quadratic Assignment Problem. Solution to the formulation is achieved by solving it by a combination of exact and heuristic methods. This solution procedure gives better results than just the heuristic method and is not computationally intensive. A computer implementation of the proposed procedure is developed in "C" programming language. A detailed experimentation is conducted to study the performance of the proposed procedure as compared to a well known procedure called Blocplan. The layouts generated by the proposed procedure are found to be much better than those generated by Blocplan. In the literature there is no discussion on the criticality of a layout to the change in flow related input data. An analysis is performed to study the affect of change in flow related input data on the final layout and a measure is developed for determining the criticality of a given layout to the change in flow related input data for the case of equal size departments. / M.S.

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