Thesis (Dipl.-Ing.)--Johannes Kepler Universität Linz, 2005. / Title from PDF title page (viewed Apr. 29, 2010). Abstract also in German. Includes bibliographical references (p. 60-63).

Thesis (M.Eng.)(Chemical)--University of Pretoria, 2004. / Includes summary. Includes bibliographical references.

Made available in DSpace on 2014-10-09T12:38:44Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:05:20Z (GMT). No. of bitstreams: 1 06007.pdf: 6761154 bytes, checksum: 544e5e82c9fa4e346e3dac046b8ce34f (MD5) / Tese (Doutoramento) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

Made available in DSpace on 2014-10-09T12:38:44Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:05:20Z (GMT). No. of bitstreams: 1 06007.pdf: 6761154 bytes, checksum: 544e5e82c9fa4e346e3dac046b8ce34f (MD5) / Tese (Doutoramento) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

University of Macau / Faculty of Science and Technology / Department of Electromechanical Engineering

No description available.

No description available.

Turnbull’s transient nucleation theory, when applied to the transformation that takes place when high purity aluminum-copper alloys are quenched directly to the aging temperature, explains the incubation period that precedes steady state nucleation. This incubation period arises from the comparatively slow rate of diffusion of solute atoms in forming the equilibrium concentration of critical size embryos which must be achieved before steady state nucleation can proceed. This rate of diffusion is a function of the temperature, degree of supersaturation, number of critical size embryos and plastic deformation. / Master of Science

Copper cast alloys de-activate antibiotic-resistant bacteria on contact and could be very effective in decreasing potentially harmful microorganisms in the environment. In this study copper alloys with varying copper contents were utilized to evaluate their antimicrobial effects on Pseudomonas aeruginosa, Escherichia coli, and Enterococcus faecium in changing environmental conditions. The survival rates of P. aeruginosa wild type and its derivative transposon mutants of the cin operon on copper cast alloys were investigated in order to demonstrate the influence of genes involved in copper resistance. The gene disruption of the response regulator of the cin operon resulted in shorter survival rates on copper alloys, which was also influenced by temperature and method of exposure. Bacteria often have acquired copper resistance mechanisms in order to withstand higher copper concentrations in their surroundings, which may be a factor in their survival rates on copper surfaces. Copper- and antibiotic-resistant E. coli and E. faecium strains were obtained from pigs raised on feeds containing copper sulfate and antibiotics. Survival rates of these bacteria were influenced by the percentage of copper in the alloys, varying moisture conditions on copper surfaces, suspension media used, and differences between strains. Survival was also dependent on copper corrosion rates since corrosion inhibition with benzotriazole or a thick surface layer of thermal oxide resulted in prolonged survival on copper surfaces. Corrosion of copper surfaces releases copper ions which directly affect bacterial survival on copper alloys. The results obtained in this study emphasize that copper alloys are effective as antimicrobial materials but changing environmental conditions can significantly influence bacterial survival on copper surfaces. These findings can be applied to a better utilization of copper alloys in water, food, and healthcare environments. Antibiotic- and copper ion-resistant bacteria can be killed on contact with copper alloys which makes the proliferation of these microorganisms less likely and reduces the risk to human health. However, in a very different environment copper ion-resistant microbes can be useful for plant-microbe associations in bioremediation of copper mining wastelands.

No description available.