Thesis (M.S.)--Missouri University of Science and Technology, 2009. / Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed January 22, 2009) Includes bibliographical references (p. 53-55).

Thesis (MS)--Montana State University--Bozeman, 2009. / Typescript. Chairperson, Graduate Committee: Steven R. Shaw. Includes bibliographical references (leaves 55-56).

Thesis (PH.D.)--Michigan State University. Chemical Engineering, 2008. / Title from PDF t.p. (viewed on Aug. 11, 2009) Includes bibliographical references (p. 179-189). Also issued in print.

Includes bibliographical references (p. 115-129).

Thesis (Ph. D.)--Oregon State University, 2007. / Printout. Includes bibliographical references. Also available on the World Wide Web.

Thesis (MTech (Chemical Engineering))--Cape Peninsula University of Technology, 2011 / High temperature polymer electrolyte membrane fuel cells (PEMFC) operating between 120-180 oC are currently of much research attention. The acid doped polybenzimidazole (PBI) membranes electrolyte are known for their tolerance to relatively high levels of carbon monoxide impurity in the feed. Most fuel cell modelling are theoretical in nature and are solved in commercial CFD platforms such as Fluent. The models require a lot of time to solve and are not simple enough to be used in complex systems such as CHP systems. This study therefore, focussed on developing a simple but yet accurate model of a high temperature PEMFC for a CHP system. A zero dimensional model for a single cell was developed and implemented in Engineering Equations Solver (EES) environment to express the cell voltage as a function of current density among others. Experimental results obtained from literature were used to validate and improve on the model. The validated models were employed for the simulation of the stack performance to investigate the effects of temperature, pressure, anode stoichiometry and the level of CO impurity in the synthesis gas, on the cell potential and overall performance. Good agreement was obtained from the simulation results and experimental data. The results showed that increasing temperature (up to 180oC) and acid doping level have positive effects on the cell performance. The results also show that the cell can operate with a reformate gas containing up to 2% CO without significant loss of cell voltage at elevated temperatures. The single cell model was extended to a 1 kWe high temperature PEMFC stack and micro-CHP system. The stacks model was validated with experimental data obtained from a test station. The model was used to investigate the performance of PEMFC and CHP system by using uncertainty propagation. The highest combined cogeneration system efficiency of 87.3% is obtained with the corresponding electrical and thermal efficiencies are 41.3% and 46 % respectively. The proposed fuel processing subsystem provides an adequate rate of CH4 conversion and acceptable CO-level, making it appropriate for integration with an HT PEMFC stack. In the steam methane reformer 97% of CH4 conversion is achieved and the water gas shift reactors achieve about 98% removal of CO.

Thesis (MTech (Mechanical Engineering))--Cape Peninsula University of Technology, 2016. / The high cost of fossil fuels and the fact that the world has arguably reached its peak oil production, has driven the need to seek alternative fuel sources. The main objective of the current study is to determine the performance of a laboratory-mounted diesel engine when fuelled with varying laboratory prepared biofuel and biodiesel and whether the advancement of the injection timing parameters will improve the engine power output and improve the smoke effect of these different fuel blends. The laboratory prepared biofuels used in this project range from 100% bio-fuel (BF100) to 50%, 30% and 10% biodiesel blends (BF50, BF30 and BF10, respectively). It should be noted that these blends are not commercially available, since they were blended in the laboratory specifically for these tests. The overall results of the study show that there is a distinct opportunity for using certain bio-fuel blends in specific applications as the power outputs are no more than one quarter less than that of base diesel. Concomitantly, the smoke opacity in all of the blends is lower than that of base diesel, which is a significant benefit in terms of their overall air emissions.

A multifunctional structural polymer electrolyte membrane (PEM) fuel cell was designed, developed and manufactured. The structural fuel cell was designed to represent the rear rib section of an aircraft wing. Custom membrane electrode assemblies (MEA s) were manufactured in house. Each MEA had an active area of 25cm2.The platinum loading on each electrode (anode and cathode) was 0.5mg/cm2. Sandwiched between the electrodes was a Nafion 212 electrolyte membrane. Additional components of the structural fuel included metallic bipolar plates and end plates. Initially all the components were manufactured from aluminium in order for the structural fuel cell to closely represent an aircraft wing rib. However due to corrosion problems the bipolar plate had to be manufactured from marine grade 361L stainless steel with a protective coating system. A number of different protective coating systems were tried with wood nickel strike, followed by a 5μm intermediate coat of silver and a 2μm gold top coat being the most successful. Full fuel cell experimental setup was developed which included balance of plant, data acquisition and control unit, and a mechanical loading assembly. Loads were applied to the structural fuel cells tip to achieve a static deflection of ±7mm and dynamic deflections of ±3mm, ±5mm, and ±7mm. Static and dynamic torsion induced 1° to 5° of twist to the structural fuel cell tip. Polarisation curves were produced for each load case. Finite element analysis was used to determine the structural fuel cell displacement, and stress/strain over the range of mechanical loads. The structural fuel cells peak power performance dropped 3.9% from 5.5 watts to 5.3 watts during static bending and 2% from 6.2 watts to 6.1 watts during static torsion. During dynamic bending (2000 cycles) the structural fuel cell peak power performance dropped 11% from 6.7 watts to 6 watts (3mm deflection at 190N), 23% from 6.3 watts to 4.8 watts (5mm deflection at 270N), and 41% from 7.2 watts to 5 watts (7mm deflection at 350N). During dynamic torsion (2000 cycles) the structural fuel cell peak power performance dropped 16% from 6 watts to 5.1 watt (3° of torsional loading), and 30% from 6.4 watts to 4.3 watts (5° of torsional loading). The simulated (finite element modelling) displacement of -6.6mm (At maximum bending load of 364.95N) was within 9% of the actual measured displacement of -7.2mm at 364.95N. Furthermore the majority of the simulated strain values were within 10% of the actual measured strain for the structural fuel cell.

Nuclear fuel failures during the reactor operation happen quite often in the world. The theoretical part of this thesis is dedicated to the most common causes of nuclear fuel failures. It describes failure mechanism and corrective actions. The unfavorable trends in nuclear fuel behavior are prevented by suitable method of nuclear fuel monitoring. Some of them may affect the safety of the power plant. For example, the fuel assembly bow affects the function of rod cluster control assembly. Another part, which describes inspection methods, is devoted to inspection and repair of nuclear fuel. The thesis concentrates on the Temelin NPP, where there was implemented post-irradiation inspection program for checking compatibility between Westinghouse's fuel assemblies and water chemistry of reactor VVER. This program continues even after the change of nuclear fuel supplier. Practical part of this thesis is dedicated to proposal of a new method of fuel assembly bow measurement for Temelin NPP based on ultrasound. This proposal is supported by measurement on the experimental device for detection of spacer grid position developed by Research Centre Rez.

Thesis (M. Tech. - (Engineering: Electrical, Department: Electronic Engineering, Faculty of Engineering and Technology)) -- Vaal University of Technology, 2011. / “Never before in peacetime have we faced such serious and widespread shortage of energy” according to John Emerson, an economist and power expert for Chase Manhattan Bank. Many analysts believe that the problem will be temporary, but others believe the energy gap will limit economic growth for years to come. A possible solution to this problem can be fuel cell technology. Fuel cells (FCs) are energy conversion devices that generate electricity from a fuel like hydrogen. The FC however, could also be used in the reverse or regenerative mode to produce hydrogen. The reversible fuel cell (RFC) can produce hydrogen and oxygen by introducing water to the anode electrode chamber, and applying a potential across the anode and cathode. This will cause the decomposition of the water to produce oxygen at the anode side and hydrogen at the cathode side. In order to make this process as efficient as possible several aspects need to be optimised, for example, the operation temperature of the RFC, water management inside the RFC and supply voltage to the RFC. A three cell RFC and its components were constructed. The three cell RFC was chosen owing to technical reasons. The design factors that were taken into consideration were the different types of membranes, electrocatalysts, bipolar plates and flow topologies. A water trap was also designed and constructed to eliminate the water from the hydrogen water mixture due to water crossover within the MEA. In order to optimise the operation of the RFC a number of experiments were done on the RFC. These experiments included the optimal operating voltage, the effect that the temperature has on the production rate of hydrogen, and the effect that the water flow through the RFC has on the production rate of hydrogen. It was found that there is no need to control the water flow through the RFC because it had no effect on the production rate of hydrogen. The results also showed that if the operating temperature of the RFC were increased, the energy it consumes to warm the RFC significantly decreases the efficiency of the whole system. Thus the RFC need not be heated because it consumes significantly more energy to heat the RFC compared to the energy available from the hydrogen produced for later use. The optimised operating voltage for the three cell RFC was found to be 5.05 V. If the voltage were to be increased or decreased the RFC efficiency would decrease.