The majority of Eskom's 22kV lines use wood as the support structure material. The economics of wood pole cross arms and their flashover withstand capabilities outweigh those of steel cross arms. However, wood pole structures are vulnerable to what is known as a Pole Top Fire. When insulators and wood cross arms become polluted, small and sustained leakage currents flow along the surface of the insulator and thereafter into the wood itself. This eventually leads to burning of the wood. Many of the 22kV lines traverse vast rural lands, going over people's path ways. If this fire is not discovered timeously, it can cause breakage of the relevant cross arm or the pole itself. A broken cross arm usually causes the outer phase conductor to hang between one and two meters above ground. When it's dark, rural inhabitants cannot see clearly and walk directly into these low lying energized conductors which cause severe injuries and often fatalities. Low hanging conductors cannot be detected electrically and are potentially hazardous to humans and animals. Safety is currently one of the highest priorities for Eskom Distribution and hence there is a dire need to mitigate Pole Top Fires. The researcher hypothesizes that the implemented mitigating technique of bonding does not eliminate Pole Top Fires. In this study accurate statistics on Pole Top Fires in KwaZulu - Natal are provided and causes of fires investigated to provide an understanding thereof. Two basic mechanisms of burning have been identified and explained. These are surface tracking and sparking, and internal sparking. This has helped to explain what mitigation techniques will be effective. A critical analysis on the performance of recommended mitigation techniques is conducted. This study therefore aims to conclude on the effectiveness of implemented techniques to mitigate Pole Top Fires. By comprehensive and critical analysis of a complex operational and safety related problem technical options for mitigating or eliminating the fires are identified, critically analyzed and only those options that are really technically feasible are proposed. This has not been properly done in Eskom before. It is within this context that this research has been undertaken. / Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2007.

Despite emerging water shortages, most water is only used once, and often with low efficiency. However, with appropriate treatment, water can be re–used to reduce the demand on freshwater sources. The Department of Water Affairs, South Africa, promotes industries to reduce discharges into water resources in order to sustain an overall good water quality of all water systems. All of this ultimately leads to industries striving towards zero effluent discharge. Primary Column Bottoms (PCBs) is a wastewater stream derived from the Fischer–Tropsch Gas to Liquid process and consists mainly of organic acids, but no nitrogen or phosphorous, which by implication excludes possible biodegradation. In the operation of cooling towers in industrial processes, cooling water quality has a direct impact on the cooling performance of the system, where nutrient levels may affect fouling, scaling and corrosion observed in the cooling towers. Fouling, scaling and corrosion affect the operating efficiency of cooling water systems and may necessitate the addition of chemical agents to control these phenomena. This has a financial and labour time impact on the operation of these systems. In this study a mini cooling tower test rig was operated with a synthetic PCB effluent as cooling water and various cycles of concentration, pH and linear flow velocities (LFVs). A constant delta temperature of 10 °C was maintained. Cycles of concentration (COC) evaluated included 2, 4 and 6 cycles of concentration and linear flow velocities evaluated was 0.6 m/s, 0.9 m/s and 1.2 m/s. Fouling, scaling and corrosion rates were determined using corrosion coupons and heat exchanger tubes for mild steel and stainless steel. Besides the evaluation of the various operational parameters for fouling, scaling and corrosion, the possibility for chemical oxygen demand (COD) removal by operating the cooling tower as a bioreactor was also evaluated. To this end nutrient correction was applied to the reactor to allow for a CNP ratio of 100:10:1. With regard to fouling, scaling and corrosion, mild steel was more affected by fouling, scaling and corrosion compared to stainless steel where almost no fouling, scaling and corrosion was observed. Overall increased linear flow velocities resulted in higher fouling and scaling rates, whereas lower linear flow velocities resulted in decreased corrosion rates. In terms of cycles of concentration, increased COC resulted in higher fouling, scaling and corrosion rates. Despite the high nutrient removal levels, the accompanying fouling, scaling and corrosion was still below the particular industry’s guidelines. Besides physical–chemical evaluation of the towers under the various operational conditions, culture–dependent and culture–independent methods were also employed. Concerning culture–dependent approaches the study demonstrated that aerobic and anaerobic organisms are present in both the planktonic and sessile phase of the cooling tower reactors. Heterotrophic aerobes were found to be the most abundant under all the operating conditions. Sulphate reducing bacteria were more abundant in the sessile phase of the cooling towers, and the presence of high sulphate levels in the experiments could be indicative of the sulphate reducing bacteria actively participating in the microbial community. Lower than expected corrosion levels, however, suggest that a combination of the organisms in the biofilm rather than sulphate reducing bacteria alone, contributed to the corrosion rates observed. Culture–independent methods, specifically phospholipid fatty acid analysis supported the results from the culture–dependent methods. Furthermore results demonstrated that linear flow velocity had a greater effect on the community structure than cycles of concentration. Finally molecular methods, specifically denaturing gradient gel electrophoresis, found that increasing cycles of concentration resulted in increased microbial community diversity, while increasing linear flow velocity resulted in decreased microbial community diversity. Regarding COD removal, nutrient correction of the synthetic PCB effluent achieved 89.35 % COD removal at 2 COC and 1.2 m/s LFV, while 80.85 % COD removal was achieved at 4 COC at 1.2 m/s LFV. From these results it was recommended that the operation of the cooling tower should be at 4 COC and 1.2 m/s, which despite slightly lower % COD removal, were characterised by fouling, scaling and corrosion rates well within guidelines. / Thesis (M. Environmental Science)--North-West University, Potchefstroom Campus, 2012.

Despite emerging water shortages, most water is only used once, and often with low efficiency. However, with appropriate treatment, water can be re–used to reduce the demand on freshwater sources. The Department of Water Affairs, South Africa, promotes industries to reduce discharges into water resources in order to sustain an overall good water quality of all water systems. All of this ultimately leads to industries striving towards zero effluent discharge. Primary Column Bottoms (PCBs) is a wastewater stream derived from the Fischer–Tropsch Gas to Liquid process and consists mainly of organic acids, but no nitrogen or phosphorous, which by implication excludes possible biodegradation. In the operation of cooling towers in industrial processes, cooling water quality has a direct impact on the cooling performance of the system, where nutrient levels may affect fouling, scaling and corrosion observed in the cooling towers. Fouling, scaling and corrosion affect the operating efficiency of cooling water systems and may necessitate the addition of chemical agents to control these phenomena. This has a financial and labour time impact on the operation of these systems. In this study a mini cooling tower test rig was operated with a synthetic PCB effluent as cooling water and various cycles of concentration, pH and linear flow velocities (LFVs). A constant delta temperature of 10 °C was maintained. Cycles of concentration (COC) evaluated included 2, 4 and 6 cycles of concentration and linear flow velocities evaluated was 0.6 m/s, 0.9 m/s and 1.2 m/s. Fouling, scaling and corrosion rates were determined using corrosion coupons and heat exchanger tubes for mild steel and stainless steel. Besides the evaluation of the various operational parameters for fouling, scaling and corrosion, the possibility for chemical oxygen demand (COD) removal by operating the cooling tower as a bioreactor was also evaluated. To this end nutrient correction was applied to the reactor to allow for a CNP ratio of 100:10:1. With regard to fouling, scaling and corrosion, mild steel was more affected by fouling, scaling and corrosion compared to stainless steel where almost no fouling, scaling and corrosion was observed. Overall increased linear flow velocities resulted in higher fouling and scaling rates, whereas lower linear flow velocities resulted in decreased corrosion rates. In terms of cycles of concentration, increased COC resulted in higher fouling, scaling and corrosion rates. Despite the high nutrient removal levels, the accompanying fouling, scaling and corrosion was still below the particular industry’s guidelines. Besides physical–chemical evaluation of the towers under the various operational conditions, culture–dependent and culture–independent methods were also employed. Concerning culture–dependent approaches the study demonstrated that aerobic and anaerobic organisms are present in both the planktonic and sessile phase of the cooling tower reactors. Heterotrophic aerobes were found to be the most abundant under all the operating conditions. Sulphate reducing bacteria were more abundant in the sessile phase of the cooling towers, and the presence of high sulphate levels in the experiments could be indicative of the sulphate reducing bacteria actively participating in the microbial community. Lower than expected corrosion levels, however, suggest that a combination of the organisms in the biofilm rather than sulphate reducing bacteria alone, contributed to the corrosion rates observed. Culture–independent methods, specifically phospholipid fatty acid analysis supported the results from the culture–dependent methods. Furthermore results demonstrated that linear flow velocity had a greater effect on the community structure than cycles of concentration. Finally molecular methods, specifically denaturing gradient gel electrophoresis, found that increasing cycles of concentration resulted in increased microbial community diversity, while increasing linear flow velocity resulted in decreased microbial community diversity. Regarding COD removal, nutrient correction of the synthetic PCB effluent achieved 89.35 % COD removal at 2 COC and 1.2 m/s LFV, while 80.85 % COD removal was achieved at 4 COC at 1.2 m/s LFV. From these results it was recommended that the operation of the cooling tower should be at 4 COC and 1.2 m/s, which despite slightly lower % COD removal, were characterised by fouling, scaling and corrosion rates well within guidelines. / Thesis (M. Environmental Science)--North-West University, Potchefstroom Campus, 2012.

A large portion of the existing building stock in North America is comprised of post-World War II high-rise apartment buildings, particularly in the Greater Golden Horseshoe in Ontario. They are home to a large portion of the Canadian population. These buildings are nearly 50 years old and reaching the end of their useful lifespan. Significant deterioration has lead to life safety concerns, poor standards of living, and aesthetic degradation. They also consume a significant amount of energy resulting in contributing to Canada’s high per capita greenhouse gas emissions. This thesis investigates the impact of various retrofit strategies on the energy consumption, durability, and occupant comfort of the towers. The building enclosure is the primary focus. The impacts were analyzed using three approaches. Whole building energy consumption was simulated by adapting a spreadsheet based Building Energy and Loads Analysis (BELA) model, originally intended for office buildings. Heat flow and temperatures across the enclosures were modeled using a two-dimensional finite element model (Therm 5.2). A single, theoretical building dubbed the, “Archetype”, was developed to define the characteristics of a “typical” tower using details extracted from four sets of drawings for towers built in Toronto during the late 1960s. Various quantities and configurations of thermal insulation were added to the Archetype and the resulting effective thermal resistances were modeled. Adding insulation to the interior significantly reduces the effectiveness of any added thermal resistance. Insulating on the exterior allows the insulation around the balconies to reach 80% of its rated value, even without insulating the balconies. Energy efficiency measures (EEMs) including retrofitting the walls, windows, appliances, or HVAC equipment were simulated and it was found that each on its own did not have a major impact on annual energy consumption. Packages of EEMs were created and simulated. It was found that a basic and high-performance whole building retrofit packages would save approximately 40% and 55% of the annual energy consumption, respectively, based on the Archetype. An analysis and discussion of the enclosure retrofit impacts on freeze-thaw potential, interior surface and interstitial condensation, occupants’ thermal comfort, and passive thermal comfort was completed. An interior versus exterior enclosure retrofit comparison summary illustrated that an exterior enclosure retrofit has significant benefits relative to an interior retrofit including ease of construction, greater durability, and improved comfort. The difference in annual energy reduction between an interior and exterior enclosure retrofit was small.

Thesis (Ph.D.)--University of Tulsa, 1985. / Bibliography: leaves 78-80.

Thesis (Ph.D.)--University of Tulsa, 1985. / Bibliography: leaves 78-80.

Thesis (M.Eng. (Chemical Engineering)) -- Universiteit van Pretoria, 2007. / Includes bibliographical references.

Thesis (Master)--İzmir Institute Of Technology, İzmir, 2005. / Keywords: Artificial neural networks, fuzzy logic, modeling, cooling load, prediction. Includes bibliographical references (leaves. 44-45).

Thesis (M.Eng.)(Chemical Engineering)--University of Pretoria, 2006. / Accompanied by a CD-ROM: Appendix B. Cooling tower model results. Includes bibliographical references. Available on the Internet via the World Wide Web.

Thesis (M.Tech.:Biotechnology)-Dept. of Biotechnology, Durban University of Technology, 2007 xvi, 185 leaves / Spirulina is a blue-green, multicellular, filamentous cyanobacterium that can grow to sizes of 0.5 millimetres in length. It is an obligate photoautotroph and has a pH growth range from 8.3 to 11.0.The large-scale production of Spirulina biomass depends on many factors, the most important of which are nutrient availability, temperature and light. These factors can influence the growth of Spirulina and the composition of the biomass produced by changes in metabolism. Brine effluent from cooling towers of electricity generating plants may provide an ideal growth medium for Spirulina based on its growth requirements, i.e. high alkalinity and salinity. The aim of this research was to optimise brine effluent from cooling towers by supplementing it with salts, in order to use this optimised effluent in a small open laboratory raceway pond in an attempt to increase the biomass production of Spirulina.