Thesis (M.H.A.)--University of Michigan, 1962.

Thesis (Ph.D.)--Electrical and Computer Engineering, Georgia Institute of Technology, 2008. / Committee Chair: Skrinjar, Oskar; Committee Member: Oshinski, John; Committee Member: Tannenbaum, Allen; Committee Member: Vela, Patricio; Committee Member: Yezzi, Anthony

Thesis (M.S.)--Medical College of Ohio, 2004. / "In partial fulfillment of the requirements for the degree of Master of Science in Occupational Health." Major advisor: Farhang Akbar. Includes abstract. Document formatted into pages: iv, 75 p. Title from title page of PDF document. Includes bibliographical references (p. 58-68).

Thesis (M.H.A.)--University of Michigan, 1962.

No description available.

Undertaken in conjunction with JUMP (Joint Universities Masters Programme in Hydrology and Water Resources). Bibliography: leaves 76-83. Establishes a methodology using genetic algorithms to find the optimum operating policy for variable speed pumps in a water supply network over a period of 24 hours.

Made available in DSpace on 2014-11-10T11:09:39Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-02-28Bitstream added on 2014-11-10T11:58:06Z : No. of bitstreams: 1 000790142_20150301.pdf: 390914 bytes, checksum: 95b9a220b9d4a5482156b1dec041ab78 (MD5) Bitstreams deleted on 2015-03-03T12:45:18Z: 000790142_20150301.pdf,Bitstream added on 2015-03-03T12:45:55Z : No. of bitstreams: 1 000790142.pdf: 682383 bytes, checksum: 3dbc82ed1f73520c8bd02ab9d953a065 (MD5) / A contaminação cruzada é um dos principais fatores que contribuem para os surtos de doenças de origem alimentar. Estima-se que até 60% dos casos de doenças transmitidas por alimentos estejam relacionados às práticas inadequadas, como a contaminação cruzada envolvendo superfícies de corte, onde a carne de frango crua é manipulada concomitantemente a outros alimentos. Dentre os micro-organismos responsáveis por causar doenças de origem alimentar, destaca-se Salmonella spp., sendo o sorovar S. Enteritidis o mais envolvido nos casos de infecções humanas além de ser reconhecida pela sua capacidade de aderir, colonizar e formar biofilme em superfícies de contato com alimentos. O biofilme permite que as bactérias se desenvolvam e cresçam aderidas a superfícies conferindo resistência aos processos de higienização, podendo causar contaminação durante o preparo dos alimentos. Assim, 10 cepas de S. Enteritidis foram utilizadas para testes de contaminação cruzada entre três superfícies de corte (plástico, madeira e vidro) e pepinos antes e depois da higienização. Além disso, essas cepas foram avaliadas quanto a sua capacidade de formar biofilme em materiais hidrofóbicos (madeira e plástico) e hidrofílicos (vidro). Quando as superfícies testadas não foram higienizadas houve a recuperação das células bacterianas de todas as superfícies e, depois, em todos os pepinos em contato com essas superfícies. Em relação às superfícies de corte higienizadas, o vidro foi o material que apresentou a menor recuperação do patógeno e a menor ocorrência de contaminação cruzada para pepinos. Entre as 10 cepas testadas, três (30%) não foram capazes de produzir biofilme em nenhumas das superfícies analisadas, mesmo possuindo os genes csgD e adrA. A maior porcentagem de produção de biofilme ocorreu na madeira e no plástico (60% e 40%, respectivamente) seguido do vidro (10%), mostrando que a bactéria adere melhor em ... / The cross-contamination is one of the main factors which contribute to foodborne outbreak. It is estimated that about 60% of foodborne diseases are related to the inappropriate practices, such as cross-contamination involving cutting surface, where the raw chicken is manipulated concurrently to other food. Among the microorganisms responsible by causing foodborne diseases, we can highlight the Salmonella spp., being the serovar Salmonella Enteritidis the one most involved in cases of infection in humans besides being recognized by its capacity to adhere, colonize and biofilm formation on surfaces of contact with food. The biofilm allows the bacteria to develop and grow adhered to surfaces offering resistance to the hygienic process, being able to cause contamination during the food prepare. Thus, 10 strains of S. Enteritidis were used to test the cross-contamination among three cutting surfaces (plastic, wood and glass) and cucumbers before and after hygiene. Besides, these strains were evaluated to their capacity to form biofilm in hydrophobic materials (wood and plastic) and hydrophilic (glass). When the tested surfaces were not sanitized there was the recovering of Salmonella on all the surfaces and in the cucumbers which had contact with these surfaces. Related to the cutting surfaces under sanitized process, the glass was the material with less recovering of the pathogen and the lower occurrence of cross contamination with the cucumbers. Among the 10 strains, three (30%) were not able to produce biofilm in any surface, even in a presence of csgD and adrA genes. The largest percentage of biofilm production occurred on the wood and plastic (60% and 40%, respectively) followed by glass (10%), showing the bacteria adhere better in hydrophobic material. It is possible to conclude that the cutting surfaces represent a critical point in cross-contamination, mainly when they weren’t sanitized. S. Enteritidis was able to form biofilm in ...

Membrane technology can be utilised for the high purification and desalination of water. However membrane filtration processes are commonly impeded by membrane fouling, which can lead to flux decline and an overall reduction in separation efficiency within the process. Therefore the aim of this research study was a comprehensive investigation of the issue of biofouling on industrial RO membranes through molecular biology techniques, characterisation of surface charge of foulant bacteria and RO membrane surface and AFM imaging and force measurements on clean and fouled membranes for the determination of adhesion force and micromechanical properties. The laboratories within Gwangju Institute of Science and Technology, South Korea and Swansea University, Wales were equipped for the scope of this research work. Research focused on the extraction of microbial DNA obtained from fouling layers on the surface of Reverse Osmosis Membranes obtained from the Fujairah Water and Power Plant, UAE. The use of the culture independent method of the molecular technique based on the 16S rDNA sequence and constructed gene libraries, was then used to determine the bacterial species that caused significant fouling on the RO membrane. Four bacterial species isolated from the fouling layer from the RO membrane were characterised in terms of electrophoretic mobility and zeta potential to determine the cell surface charge within various industrial relevant environments for the elucidation of cell adhesion mechanisms to the membrane surface. AFM images of virgin and fouled membranes were obtained and analysed to reveal the roughness of the surface which could influence fouling and the surface charge of the membranes were measured through the method of streaming potential at various industrial relevant environments to further elucidate the mechanisms of cell adhesion to the membrane surface. Force measurements were performed to reveal the adhesion force and elasticity values of virgin, process fouled and purposely fouled with the four bacterial isolates, to determine process behaviour in various environmental conditions. Through this research and future work, it is hoped that a rational strategy for economic and effective cleaning processes will be developed which will maintain efficient membrane operation and prolong membrane life, thus enabling the reduction of operating costs of such processes.

Orientador: Vera Lúcia Mores Rall / Banca: Rodrigo Taanelli Hernandes / Banca: José Paes de Almeida Nogueira / Resumo: A contaminação cruzada é um dos principais fatores que contribuem para os surtos de doenças de origem alimentar. Estima-se que até 60% dos casos de doenças transmitidas por alimentos estejam relacionados às práticas inadequadas, como a contaminação cruzada envolvendo superfícies de corte, onde a carne de frango crua é manipulada concomitantemente a outros alimentos. Dentre os micro-organismos responsáveis por causar doenças de origem alimentar, destaca-se Salmonella spp., sendo o sorovar S. Enteritidis o mais envolvido nos casos de infecções humanas além de ser reconhecida pela sua capacidade de aderir, colonizar e formar biofilme em superfícies de contato com alimentos. O biofilme permite que as bactérias se desenvolvam e cresçam aderidas a superfícies conferindo resistência aos processos de higienização, podendo causar contaminação durante o preparo dos alimentos. Assim, 10 cepas de S. Enteritidis foram utilizadas para testes de contaminação cruzada entre três superfícies de corte (plástico, madeira e vidro) e pepinos antes e depois da higienização. Além disso, essas cepas foram avaliadas quanto a sua capacidade de formar biofilme em materiais hidrofóbicos (madeira e plástico) e hidrofílicos (vidro). Quando as superfícies testadas não foram higienizadas houve a recuperação das células bacterianas de todas as superfícies e, depois, em todos os pepinos em contato com essas superfícies. Em relação às superfícies de corte higienizadas, o vidro foi o material que apresentou a menor recuperação do patógeno e a menor ocorrência de contaminação cruzada para pepinos. Entre as 10 cepas testadas, três (30%) não foram capazes de produzir biofilme em nenhumas das superfícies analisadas, mesmo possuindo os genes csgD e adrA. A maior porcentagem de produção de biofilme ocorreu na madeira e no plástico (60% e 40%, respectivamente) seguido do vidro (10%), mostrando que a bactéria adere melhor em ... / Abstract: The cross-contamination is one of the main factors which contribute to foodborne outbreak. It is estimated that about 60% of foodborne diseases are related to the inappropriate practices, such as cross-contamination involving cutting surface, where the raw chicken is manipulated concurrently to other food. Among the microorganisms responsible by causing foodborne diseases, we can highlight the Salmonella spp., being the serovar Salmonella Enteritidis the one most involved in cases of infection in humans besides being recognized by its capacity to adhere, colonize and biofilm formation on surfaces of contact with food. The biofilm allows the bacteria to develop and grow adhered to surfaces offering resistance to the hygienic process, being able to cause contamination during the food prepare. Thus, 10 strains of S. Enteritidis were used to test the cross-contamination among three cutting surfaces (plastic, wood and glass) and cucumbers before and after hygiene. Besides, these strains were evaluated to their capacity to form biofilm in hydrophobic materials (wood and plastic) and hydrophilic (glass). When the tested surfaces were not sanitized there was the recovering of Salmonella on all the surfaces and in the cucumbers which had contact with these surfaces. Related to the cutting surfaces under sanitized process, the glass was the material with less recovering of the pathogen and the lower occurrence of cross contamination with the cucumbers. Among the 10 strains, three (30%) were not able to produce biofilm in any surface, even in a presence of csgD and adrA genes. The largest percentage of biofilm production occurred on the wood and plastic (60% and 40%, respectively) followed by glass (10%), showing the bacteria adhere better in hydrophobic material. It is possible to conclude that the cutting surfaces represent a critical point in cross-contamination, mainly when they weren't sanitized. S. Enteritidis was able to form biofilm in ... / Mestre

Thesis (MDiploma (Mechanical Engineering))--Cape Technikon, 1992. / An investigation into the use of thermoelectric cooling energised by photovoltaic (PV) panels for removing sensible heat from electronic telecommunications equipment. The thermoelectric cooler consists of a solid-state heat pump which operates on the principle of the Peltier effect. The thermoelectric device transfers heat through a cold sink to ambient outside air via a hot sink. A major prerequisite was that the system should be selfsufficient in terms of power because the sites for the microwave transmitters are often remote. Solar power was the only alternative source of energy and the cooler was designed to accept direct current from PV panels which are usually used to power transmitters on distant locations. The cooling device had to be reliable, virtually maintenance-free and simple to repair.