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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.
1

Development of polyesters as propellant inhibitors

Hsu, Yao-Sheng 01 July 2003 (has links)
Abstract Two kinds of unsaturated polyesters¡¦ prepolymers were synthesized via two steps. For the hard segment, isophthalic acid was reacted with 1,2-propanediol first, then maleic anhydride was added to yield a copolyester with Tg around 13
2

Development of Inhibiting Materials Resistant to Nitroglycerine Migration

Chen, Chi-he 12 July 2004 (has links)
Oligomers of hard and soft segments of unsaturated polyesters were synthesized in two steps. For the hard segment, isophthalic acid was reacted with 1,2-propanediol first, then maleic anhydride was added for further esterification. For the soft segment, diethylene glycol was used to replace 1,2-propanediol. In the previous study, the excess amount of glycol was 20% in weight. In this study, glycol was 10 and 5 wt% in excess, respectively. Decreasing the excess amount of glycol from 20 to 5 wt%, the number average molecular weight of both hard and soft segments increased about 30-40% from 1000 g/mol, and the degree of isomerization of maleic acid changed from 40.5 to 57.3% for the oligomers of the soft segment. The hard and soft segments synthesized in this study were blended in weight ratios from 0 to 100 % in an interval of 20 %, and then cured with styrene for further mechanical testing. The micro-tensile strength of cured soft and hard segments increased 1.3 and 8 times, respectively, in this study compared with that of specimens prepared under the condition of 20 wt% in excess of glycol. Therefore, the criteria of inhibitors can also be achieved by varying the excess amount of glycols. To evaluate the nitroglycerine migration and the erosion rate, only two (60% hard segment and 40% soft segment) of the formulas which passed the criteria of mechanical properties were investigated by replacing lithophone with magnesium hydroxide. In the case of 10 wt% in excess of glycol, the migration of nitroglycerine at infinite time (M
3

Biological Health Assessment of an Industrial Wastewater Treatment Facility

Zivich, Jamie Dionne 08 August 2011 (has links)
The biological treatment of wastewaters from an industry was studied. Among the more important wastewater constituents of concern were high levels of suspended solids, due to graphite and nitrocellulose, the solvents, ethanol and acetone, and nitroglycerine (NG). The goal of this project was divided into four objectives. The impacts of graphite on a microbial population were evaluated. Sequencing batch reactors (SBRs) were used to monitor the effects of graphite on mixed liquor suspended solids (MLSS), removal of soluble chemical oxygen demand (sCOD), and specific oxygen uptake rates (sOUR). Graphite appeared to have no adverse effect on the microbes. The potential benefits of adding sucrose, nitrogen, and phosphorus to SBRs were evaluated. The MLSS was maintained at 1,250 mg/L, similar to the microbial population in the suspended growth system at the industry. Sucrose addition increased the sCOD removals and sOUR. No direct effect was observed with the addition of nitrogen and phosphorus. The treatability of acetone and ethanol was studied through sOUR and batch testing to determine bacterial response to solvents. Both solvents were utilized by the microbes. The concentrations tested proved to be beneficial, not inhibitory. Ethanol and a 50/50 mixture of acetone and ethanol were more viable substrates than acetone. NG treatability was examined under anoxic and aerobic conditions in SBRs and batch biological reactors. NG degradation occurred under anoxic conditions, but was more favorable in aerobic environments. NG was degraded in all SBR tests to below detection limit (0.5 mg/L); therefore, the optimal treatment could not be determined. / Master of Science

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