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No description available.

Call number: LD2668 .T4 1979 N89 / Master of Science

The problem solved in this thesis is one of transient linear heat conduction in a two layer, three-dimensional slab subjected to an arbitrary heat flux on one surface, where each layer is thermally orthotropic. The sides and bottom of the slab are either insulated (Bi = 0) or held at a constant temperature (Bi = infinity). The Biot number of the top surface varies from zero to infinity. The solution is developed by decomposing the problem into a number of simpler problems, each of which is solved using eigenfunction expansions. In the vertical direction, the eigenvalue problem is solved using the Krawczyk algorithm, and an orthogonality relationship is found by Vodicka's method.

by Ho Kam-ho. / Chinese title: / Bibliography: leaves 133-134 / Thesis (M.Phil.) -- Chinese University of Hong Kong, 1983

Tsui Pui Yuen = 納米鈀硅合金比容的硏究 / 徐沛源. / Thesis submitted in 2000. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2001. / Includes bibliographical references. / Text in English; abstracts in English and Chinese. / Tsui Pui Yuen = Na mi ba gui he jin bi rong de yan jiu / Xu Peiyuan. / Abstract --- p.i / 摘要 --- p.ii / Acknowledgments --- p.iii / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- A New Age of Materials --- p.1 / Chapter 1.2 --- Nanocrystalline Materials --- p.1 / Chapter 1.3 --- Fabrication of Nanocrystalline Materials --- p.2 / Chapter 1.4 --- Phase Transformation --- p.3 / Chapter 1.5 --- Nucleation and Growth --- p.5 / Chapter 1.6 --- Spinodal Decomposition --- p.7 / Chapter 1.7 --- The Relation of Undercooling and the Morphology of SD --- p.9 / Chapter 1.8 --- Method to Obtain Large Undercooling --- p.9 / References --- p.11 / Figures --- p.12 / Chapter Chapter 2 --- Experimental --- p.19 / Chapter 2.1 --- Method --- p.19 / Chapter 2.2 --- Preparation of Fused Silica Tubes --- p.19 / Chapter 2.3 --- Sample Preparation --- p.19 / Chapter 2.3.1 --- Alloying --- p.19 / Chapter 2.3.2 --- Fluxing --- p.20 / Chapter 2.3.3 --- Controlled Undercooling --- p.20 / Chapter 2.4 --- Analyzing Method --- p.20 / Chapter 2.4.1 --- Measurement of density --- p.20 / Chapter 2.4.1.1 --- Theory --- p.20 / Chapter 2.4.1.2 --- Experimental Setup --- p.21 / Chapter 2.4.2 --- Microstxucture Analysis --- p.21 / References --- p.23 / Figures --- p.24 / Chapter Chapter 3 --- Results and Discussions --- p.28 / References --- p.32 / Table --- p.33 / Figures --- p.34

Digitized by Kansas Correctional Industries

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Abstract not available

Nisin, an antimicrobial peptide used in food preservation was evaluated for thermal stability. Nisin retained antimicrobial activity after having been heated at 121��C for seven hours. Anhydrous nisin and concentrated nisin solutions (5-10 mg/ml) were still active after having been heated up to 190��C or 230��C. When exposed to high temperatures of 200 or 250��C for up to one hour, nisin lost all antimicrobial activity. After 3.5 hours of heating at 121��C an inactive nisin degradation product, designated nisin L, was isolated. In comparison to native nisin, nisin L had reduced activity against Pediococcus pentosaceus FBB-61 and no activity against Bacillus cereus T vegetative cells or spores. Structural changes to nisin L were studied by high performance liquid chromatography (HPLC), ion spray mass spectroscopy (MS), ��H nuclear magnetic resonance spectroscopy (NMR) and circular dichroism (CD) spectroscopy and compared to original nisin. There was no difference in molecular weight between nisin and nisin L. Both MS spectra contained nisin, with average molecular weight (MW) of 3354 daltons (D), and hydrated nisin with average molecular weight of 3372 D. Nisin L had higher proportion of hydrated molecules, and it had molecules with more then one water addition. Proton NMR analysis of nisin L indicated that dehydrobutyrine 2 and dehydroalanine 5 residues had been altered, and that several new hydrogen resonances appeared. Water additions in nisin L are likely to have occurred at dehydroresidues, making them inactive. Nisin L was found to be more polar, as would be expected for a more hydrated peptide. Analysis of CD spectra indicated that nisin L had smaller content of a helix and therefore lesser membrane spanning capability. Tandem mass spectroscopy of original nisin revealed that it was hydrated at lysine 34 residue. / Graduation date: 1996