No description available.

No description available.

Avhandling--Göteborg, 2003. / Bibliogr. p. 355-370. Index. Résumé en anglais.

No description available.

Bochum, Univ., Diss., 2001. / Computerdatei im Fernzugriff.

Bochum, Univ., Diss., 2001. / Computerdatei im Fernzugriff.

Bochum, Universiẗat, Diss., 2001.

Selective ester bond cleavage using lithium and zinc halides was attempted in a select group of phospholipids, namely phosphatidylcholine (PC), phosphatidylethanolamine (PE), and phosphatidylserine (PS). Several reaction parameters including catalyst (lithium chloride, lithium bromide, lithium iodide, zinc chloride, zinc bromide and zinc iodide), reaction temperature (21, 30, 50 and 60 oC), and reaction time (2 and 4 hours) were varied and the effects on cleavage studied. Reacted phospholipid samples were characterized by attenuated total reflectance (ATR) and transmission FTIR spectroscopy. The FTIR spectra of pure (unreacted) and reacted PC, PE and PE were analyzed qualitatively and quantitatively (Peak Height Ratio). The appearance of asymmetric carboxylate anion stretch (1577 cm-1) and symmetric phosphonyl dianion stretch (1006 cm-1) in the reacted phospholipid spectra reveals cleavage of ester bonds in carbonyl and phosphonyl. Reaction temperature and time did not significantly influence the cleavage results over the temperature and time range tested.

Five series of PT-30/organoclay (Cloisite 10A, Cloisite 30B, Nanomer I.28E, Nanomer I.30E and Nanomer I.44PA) composites were prepared and characterized. The dispersion of clay tactoids in PT-30 resin was studied by XRD and TEM. XRD analyses determined that the d-spacings of each nanoclays of these were expanded upon dispersing in the PT-30 matrix versus the as-received clay. TEM micrographs further demonstrated that the intercalation of clay layers by PT-30 occurred during the curing process. Histograms of clay tactoids distributions were generated based on the combination of XRD and TEM results. The glass transition temperatures (Tg) of selected PT-30/clay composites were measured by DSC and compared. Partial clay exfoliation with some resin intercalation was demonstrated. The average flexural strengths and flexural moduli of all composites were obtained using three-point bending tests.

Increasing fuel prices, stricter government policies, and technological developments made it possible to seek for renewable alternatives, called biofuels, to petroleum fuel. Biodiesel, a biofuel that is produced from chemically mixing animal fat, vegetable oils, or recycled restaurant grease with alcohol and catalyst, is gaining popularity in recent years as a substitute for petroleum diesel. Ninety percent (90%) of U.S. biodiesel industry makes use of soybean oil as its feedstock. However, soybean oil alone cannot meet such a huge demand on biofuel production. Hence, it is important to identify and get more information about other feedstocks, specifically on its effects on the performance and exhaust emissions of diesel engines. The purpose of this study is to investigate the performance and emissions of two diesel engines operating on different biodiesel fuels (i.e. canola oil, sunflower oil, safflower oil, peanut oil, and chicken fat) and compare them to the performance and emissions when the engine is operated on soybean oil-based biodiesel and petroleum-based diesel. Results indicated that an engine operating on biodiesel generates a little less power and torque at any given speed than one running on diesel. Such power and torque loss were attributed to the biodiesel's lower energy content. The lower heating value (energy content) of biodiesel can be reflected in the specific fuel consumption, i.e., to generate the same power, more biodiesel is needed. The reduction in torque and power of less than 10% indicates that in some cases biodiesel has better combustion than diesel. Unfortunately, the high efficiency of combustion may give rise to increased combustion temperature which may lead to higher exhaust emissions. The gradual decrease in the total hydrocarbon and CO2 emissions, as blends were increased from B20 to B100, was also found to be an indication of better combustion using biodiesel fuels than petroleum diesel. However, NOx emissions were higher, predominantly at low speeds for most biodiesel and blends and therefore may require some additives or engine modifications/or adjustments to equalize the NOx emissions of diesel. Other emissions particularly SO2 were lower than standards require.