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In the past, the emission of SO[2], NO[x] and CO[2] gasses, as a result of the combustion of fossil fuels within the power industry has been a major contributor to the pollution of the environment. Controls over the last few years have been implemented to combat the effects of air pollution on the environment. One such control is the reduction of sulphur dioxide (SO[2]) from power stations, which is achieved by fitting desulphurisation systems to new and existing installations. At present there are many types of desulphurisation processes available, which produce a variety of wastes that vary in quality and quantity. The majority of processes fit into three main categories, wet, semi dry and dry desulphurisation processes. Desulphurisation systems work by introducing alkaline sorbents, such as limestone, to the SO[2] gasses, either during or after combustion. The limestone reacts with the SO[2] gasses to form new insoluble materials such as gypsum (CaSO[4].2H[2]O). However, semi-dry and dry processes produce wastes that are usually a blend of fly ash and some form of calcium sulphate. The wide variation in chemical, physical and mineralogical properties of the wastes produced hinders their utilisation, because general experimental investigations are only relevant to specific types of wastes. In addition, the wastes can contain large quantities of sulphates, which are normally limited to a few percent in plain cements to regulate setting, and therefore, their initial potential appears limited. The current investigation aims to evaluate the performance of paste, mortar and concrete that contain large quantities of actual and simulated desulphurised wastes. Members of the Copernicus project (1999) provided various desulphurised wastes from Eastern European installations for investigation. Fly ash and gypsum from UK sources were blended in different proportions to simulate desulphurised wastes based on a range of SO[3] contents typically associated with actual desulphurised wastes produced throughout Eastern Europe. Several tests were conducted on paste, mortar and concrete containing actual and simulated desulphurised wastes to investigate basic physical, mechanical and durability properties. These include chemical shrinkage, porosity and pore size distribution, water absorption, length change, compressive strength, and sulphate resistance. The outcomes of investigation were positive in that cement based materials containing high levels of desulphurised wastes were produced, which exhibit physical, mechanical, and durability properties equal or superior to reference cements, and cements containing more common replacement materials such as fly ash and slag. Attempts were made to correlate specific properties such as chemical composition, porosity and pore size distribution, and chemical shrinkage with strength in order to determine the key factors influencing strength development of cement-based materials containing desulphurised wastes. The relationship between SO[3] content and compressive strength of pastes containing simulated desulphurised wastes (FA-G blends) was used to predict the theoretical strength of cement-based materials containing actual desulphurised wastes with reasonable accuracy. Thus reinforcing the decision to evaluate simulated desulphurised wastes due to the diverse nature of desulphurised wastes currently available across Eastern Europe.

Two basic types of photovoltaic (PV) array simulator have been designed and tested. The first involves the use of a pilot panel and variable light source. It is implemented with analogue circuits. A stability analysis based on Popov's method is presented for this simulator with resistance-inductance (R-L) loads. In the second, characteristic array curves are stored in the memory of a microprocessor-based simulator. The design of both simulators is based on the transfer function method. By using the computing facility available, a stability study for the Type I simulator and some dynamic simulations are carried out. Both simulators are capable of driving a special load, namely, an experimental solar pumping system. The experimental results for both types of' simulator are satisfactory in terms of steady state precision and dynamic behaviour when used with this load. Compared with previously-reported PV array simulator designs [6,7,8,9,18], the two simulators described here have the following distinctive features: 1. A new method of sample curve generation for the Type II simulator results in relatively short sampling period and small memory size. 2. The sample curves of the type II simulator are based directly on the real PV array to be simulated. They are more accurate than the sample curves in references [6,7,9]. 3. Different loads (R, R-L and an experimental solar pumping system) have been considered in the design and have been tested in laboratory. 4. A stability analysis and some dynamic simulations are presented for the type I simulator. An analysis of this type has not been reported in previous studies [6,7,8,9,18]. / Applied Science, Faculty of / Electrical and Computer Engineering, Department of / Graduate

Solar energy has come to the forefront as a scalable and largely underutilized renewable energy resource. The current cost of solar electricity, namely from photovoltaics, along with other logistics factors, has prevented the widespread adaptation of the technology. A key determinant of efficiency and cost for a solar cell is the current collector grid. This work presents the Collimated Aerosol Beam Direct Write (CAB-DW) system as a non-contact printing method that can achieve current collector grid finger widths of less than 10 μm which are amenable to decreasing both resistive and optical losses. The ability to produce high aspect ratio grid fingers, and deposit optimized grid structures on high efficiency SHJ solar cells using silver nanoparticle inks is also demonstrated. A decrease in shadowing and via profile modification of the grid fingers is presented, along with a study of aging and degradation of electrical properties within silver nanoparticle inks.

Mobile generation platforms are very common among both military and civilian applications. However, in military applications getting fuel to the front lines can come at a very high cost. This cost is both financial, costing upwards of hundreds of dollars a gallon, and human, with resupply convoys being the leading cause of casualties in today's warfront. Diesel generators operate much more efficiently at higher loads, rather than the lower loads that the systems normally operate at. To improve fuel efficiency, a hybridized generator system is proposed. This system combines a standard generator with a large rechargeable battery pack. The addition of the battery pack allows for several unique power scenarios to occur through power generation. The battery pack functions to provide an efficient storage capability for the system. During times of excess load, the battery and generator work together. This allows for algorithms to manage the generator set to operate at peak efficiency while addressing load spikes. A system like this has been theoretically designed and a simulation has been developed to determine the impact over a standard system. Actual load cycle information from military sources has been used to evaluate the concept. The results of the simulation show increase efficiency, in the low load scenarios, to more than double the standard generator efficiency. / Master of Science

At starting, electrical motors require large power and current. This may not be a problem in a large electrical system but it may be very severe for a limited power source like a solar array. If a direct approach is taken the array rating must be 5-6 times the motor rating in order to start the motor and its high inertia high friction load. Batteries have been used to store energy and supply that energy for starting. Batteries need maintenance and their low efficiency is a problem too. In this study a new type of controller has been suggested and developed for the use with D.C. motors. Computer simulation showed promising results. The controller uses the array power, which is equal to the rated power of the motor, for starting and for running condition. Experimental results showed that the theoretical results are applicable.

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No description available.

No description available.