Thesis (M.S.)--Virginia Polytechnic Institute, 1952. / Vita. Includes bibliographical references (leaves 73-75). Also available via the Internet.

Please read the abstract in the section 00front of this document / Dissertation (MEng (Electrical Engineering))--University of Pretoria, 2007. / Electrical, Electronic and Computer Engineering / MEng / unrestricted

Thesis (M. Sc.)--University of Hong Kong, 1983.

Currently, Ghana does not use Hot Water Treatment (HWT) as a phytosanitary control measure for mangoes. The effect of HW on the quality of ‘Keitt’ mangoes in Ghana was evaluated. Mangoes were washed with chlorinated water or hot water treated at 47°C for 70 min and stored at 25°C for 8 days. There was no treatment*Storage effect (P> 0.05) on the variables studied. Mangoes TA decreased (P<= 0.05) and pH increased with storage time. HWT had no impact on mango quality but had 50% reduction in decay during storage.

Generating enough heat to convert water into steam is a major expense for projects that inject steam into reservoirs to enhance hydrocarbon recovery. If the temperature of the injected fluid is lowered this expense would be reduced. In the past, attempts have been made to inject hot water instead of steam. The results have all been rather poor, the major problem being low sweep efficiency. The hot water just doesn’t enhance oil recovery enough. Adding propane to the steam injected in the reservoir lowers the boiling point of the light to intermediate hydrocarbon fractions, upgrading the oil and reducing viscosity. The goal of this investigation is to see if the same effects could be achieved when adding propane to hot water – making it a lower cost option for an injection operation. Results conclude that you need steam to achieve satisfactory recovery. These results reflect differences in heat injected by steam compared to that of hot water. Steam has a more penetrating effect, shooting into the reservoir where the hot water moves more slowly forward. The propane just doesn’t seem to have the same accelerating effect when used with water as it does when used with steam.

This study measured and compared different temperatures and dwell times of hot water treatment on the reduction of Escherichia coli O157:H7 and Salmonella Typhimurium on beef carcass surfaces. Two different types of beef surfaces, lean and fat, were inoculated with a fecal slurry containing E. coli O157:H7 and S. Typhimurium at ca. 7-log CFU/g, washed to remove gross fecal matter, and rinsed with hot water between 66 and 82 degrees C (150 to 180 degrees F water) for either 5, 10, or 15 s. There were no differences (P > 0.05) in the log reductions of S. Typhimurium and E. coli O157:H7 on the lean surfaces for all three temperature treatments (66, 74, and 82 degrees C). Although the 15 s treatment resulted in a numerically higher log reduction than the other treatments, each of the times resulted in at least a 1 log reduction of both S. Typhimurium and E. coli O157:H7 for lean surfaces. For the fat surfaces, all time treatments for the 82 degrees C and the 10 and 15 s treatments for the 74 degrees C resulted in the highest log reduction for S. Typhimurium. The 5 and 10 s dwell times for treatments at 66 degrees C and the 5 s dwell time at 74 degrees C resulted in the lowest log reduction of S. Typhimurium and E. coli O157:H7. For E. coli O157:H7 all temperature and time treatments resulted in at least a 1 log reduction for the fat surfaces of the outside round. Therefore, hot water treatment is a proven method for reducing both coliforms and pathogenic bacteria.

This study measured and compared different temperatures and dwell times of hot water treatment on the reduction of Escherichia coli O157:H7 and Salmonella Typhimurium on beef carcass surfaces. Two different types of beef surfaces, lean and fat, were inoculated with a fecal slurry containing E. coli O157:H7 and S. Typhimurium at ca. 7-log CFU/g, washed to remove gross fecal matter, and rinsed with hot water between 66 and 82 degrees C (150 to 180 degrees F water) for either 5, 10, or 15 s. There were no differences (P > 0.05) in the log reductions of S. Typhimurium and E. coli O157:H7 on the lean surfaces for all three temperature treatments (66, 74, and 82 degrees C). Although the 15 s treatment resulted in a numerically higher log reduction than the other treatments, each of the times resulted in at least a 1 log reduction of both S. Typhimurium and E. coli O157:H7 for lean surfaces. For the fat surfaces, all time treatments for the 82 degrees C and the 10 and 15 s treatments for the 74 degrees C resulted in the highest log reduction for S. Typhimurium. The 5 and 10 s dwell times for treatments at 66 degrees C and the 5 s dwell time at 74 degrees C resulted in the lowest log reduction of S. Typhimurium and E. coli O157:H7. For E. coli O157:H7 all temperature and time treatments resulted in at least a 1 log reduction for the fat surfaces of the outside round. Therefore, hot water treatment is a proven method for reducing both coliforms and pathogenic bacteria.

Escherichia coli O157:H7 and Salmonella have emerged as the most common foodborne enteric pathogens causing human illness from the consumption of beef. By mandate of the U.S. Department of Agriculture (USDA), Food Safety and Inspection Service (FSIS), the industry has implemented a Hazard Analysis and Critical Control Points (HACCP) system that utilize intervention technologies for controlling, preventing, and/or reducing enteric pathogens. In addition, USDA-FSIS has mandated that each facility must validate, monitor, and verify the effectiveness of each intervention implemented to eliminate E. coli O157:H7 and Salmonella. For this study, microbial decontamination interventions at two beef slaughter facilities were validated to demonstrate effectiveness in eliminating or reducing enteric pathogens. The facilities selected utilized either a lactic acid spray treatment or a combination of hot water followed by a lactic acid treatment. At both facilities, mesophilic plate counts (MPC) were significantly (P < 0.05) reduced, and E. coli and coliforms were eliminated below detectable limits at both facilities. No Salmonella positive samples were detected after either facility's intervention sequence. The framework used in this research to validate interventions can also be utilized in the future for yearly verification of the effectiveness of each intervention.

Generating enough heat to convert water into steam is a major expense for projects that inject steam into reservoirs to enhance hydrocarbon recovery. If the temperature of the injected fluid is lowered this expense would be reduced. In the past, attempts have been made to inject hot water instead of steam. The results have all been rather poor, the major problem being low sweep efficiency. The hot water just doesn’t enhance oil recovery enough. Adding propane to the steam injected in the reservoir lowers the boiling point of the light to intermediate hydrocarbon fractions, upgrading the oil and reducing viscosity. The goal of this investigation is to see if the same effects could be achieved when adding propane to hot water – making it a lower cost option for an injection operation. Results conclude that you need steam to achieve satisfactory recovery. These results reflect differences in heat injected by steam compared to that of hot water. Steam has a more penetrating effect, shooting into the reservoir where the hot water moves more slowly forward. The propane just doesn’t seem to have the same accelerating effect when used with water as it does when used with steam.

Solar Domestic Hot Water systems and air-source heat pumps offer the potential for energy savings in residential hot water production, however their performance is limited in cold climates, where the low ambient temperature reduces the collector efficiency or the heat pump coefficient of performance. Combining these systems into a Solar-Assisted Heat Pump can alleviate these limitations by reducing the required collector temperature and by providing an increased heat pump evaporator temperature. This study is a continuation of the development of an Indirect Solar-Assisted Heat Pump undertaken at the Queen’s University Solar Calorimetry Laboratory. Previously, a numerical study compared its performance to existing technology, and based upon this feasibility analysis, a prototype was constructed for controlled laboratory tests using simulated solar input. In the current study, the prototype was modified to include a novel hybrid collector such that its performance under actual weather conditions throughout the year could be assessed. On sunny days, the system experienced daily averaged collector efficiencies between 0.47 and 0.88, depending on the flow rate and season. Averaged heat pump coefficients of performance of 2.54 to 3.13 were observed. Overcast days experienced reduced coefficients of performance, between 2.24 and 2.44. However, on overcast days, upwards of 76% of the collected energy gain was from convection with the surroundings. Based upon these experimental results, a model for the hybrid collector was developed. Annual simulations of the system were conducted to compare the performance of the solar heat pump system when fitted with the hybrid collector relative to cases with more conventional glazed and unglazed collectors commonly used in solar thermal systems. Results were produced for three Canadian cities: Toronto, Vancouver and Winnipeg. The heat pump with the hybrid collector outperformed the other collectors in the Toronto climate, with a free energy ratio of 0.548. Adding a thermally controlled valve to the hybrid collector was proposed to further increase the annual free energy ratio, and was shown to perform best in all three cities, with free energy ratios of 0.558, 0.576 and 0.559 for Toronto, Vancouver and Winnipeg, respectively. It is proposed that additional improvements could be achieved by allowing the collectors to deliver heat directly to the storage tank, by circumventing the heat pump if the conditions were favorable. / Thesis (Master, Mechanical and Materials Engineering) -- Queen's University, 2012-01-06 13:44:41.77