This thesis explores the role the U.S. plays in the developmental process of international nonproliferation regime. The argument of this thesis is mainly based on the power-based perspective, which assumes that the U.S., the first country to obtain nuclear technology, profoundly influences the creation and persistence of the nonproliferation regime. First of all, I discuss the debate on the theories of international regime in order to highlight the applicability of power-based approach in the research of nonproliferation regime. Secondly, I examine both the nuclear policy of the U.S. and the developmental history of nonproliferation regime, so as to explain the former¡¦s impacts over the latter. Finally, I evaluate the different means and postures of the U.S. when she confronts different violators. Through this inquiry, I attempt to expose the flaw of the nonproliferation regime: the proliferation problem is still not totally suspended even after the establishment of the nonproliferation regime. The main factor of the flaw is, nonetheless, resulted from the U.S.¡¦ misapplication of her nuclear hegemonic power and her selective proliferation policy towards different violators, although she had positively contributed to the creation and persistence of the nonproliferation regime.

The use of high power converters has increased tremendously. Increased demand for transportation, housing and industrial needs means that more number of power converters interact with the utility power grid. These converters are non-linear and they draw harmonic currents, significantly affecting power quality. To reduce harmonics, filters, power factor correction circuits and capacitor banks are required. And the development of hybrid technologies and renewable energy power stations trigger a demand for power converters with bi-directional capabilities. The objective of this thesis is to develop a high power quality, bi-directional AC-DC power converter that is a solution to the aforementioned problems. This thesis studies an existing topology for a high power AC-DC power conversion with transformer isolation. The topology consists of an uncontrolled rectifier followed by a DC-DC converter to produce a set voltage output. A design example of the topology is simulated using the PSIM software package (version 6). Critical performance characteristics such as power factor and total harmonic distortion are analyzed. Following that study a new topology is proposed, which is an improvement over the older design, with reduced power conversion stages. The new topology has a fully controlled current source Pulse Width Modulation (PWM) rectifier at the front end to replace the uncontrolled rectifier and DC-DC combination. This topology has multiquadrant operational capabilities and the controller employs Selective Harmonic Elimination techniques to produce the programmed PWM switching functions for the rectifier. A design example of the converter and the digital controller are simulated in PSIM environment. The converter input current THD (Total Harmonic Distortion) and input power factor are within IEEE 519 and DoE standards. The converter is simulated in both first and fourth quadrant operations. A side-by-side comparison of the two topologies is done with respect to design and performance features such as power factor, THD, filter size, etc. The new topology converter provides performance superior to that of the older topology. Finally the thesis explores possible applications for the converter in power supplies, renewable energy and hybrid technologies.

Abstract The decrement of Nitrogen Oxide (NOx) emission can slow down the impaction to the natural environment as well as avoiding the global warming become worse continuously. The three coal fired boilers in CSC were designed as capable of multi-fuel burning but its primary fuel is coal. The original designed coal is PCI coal from Australia. The NOx emission generating while using PCI coal is around 320 ppm and can,t meet the local EPA emission requirement set for year 2001, which is 300ppm. To cope with more stringent environmental requirement, the first stage strategy is to evaluate the NOx removal technologies and selecting the optimum one of them to fight against NOx emission. By means of MCDM (Multi-Criteria Decision-Making) methodologies, SNCR is chosen due to its simplicity and acceptable NOx-out ability. The 45% NOx reduction rate can be achieved and the control NOx final output will be lower than 200ppm, which is the promised level to the local EPA. In compromising the NOx reduction requirement and the practical running cost factor, the 240ppm NOx level has been determined for operating the SNCR system. The second stage of NOx reduction evaluation is focused on the coal brands selection. It¡As believed that through the right choose of suitable coal can offer the contribution to both environment and economic. After surveying the different coal composition analysis and carrying out real trial burn, the ADARO coal from Indonesia was picked up from competition and deem as the most environment friendly coal in terms of owning the optimum coal compositions and the lowest pollutants generation including NOx, SO2, as well as ash. As a result, the ADARO coal application is highly successful in the aspects of less pollutant generation and saving cost expenditure caused by the related environment equipment systems operation and maintenance. Obviously, the positive and close relationship between environment and economic has been proved. Base on the real evidence, this paper proves that by choosing the suitable methodologies, the NOx reduction can be accomplished to some extent. The whole environment can be benefited by this action and meanwhile the air pollution tax plus operation and maintenance cost can be reduced further. It¡As hoped that by announcing this paper, the outstanding performance of remarkable NOX reduction outcome and its coat saving advantage can be applied to the whole industrial field. Let¡As work together for the purpose of decreasing the pollutants emission, lightening the harms to the natural environment and fulfilling the duties of protection the all eco system. Key words: Nitrogen Oxide, Selective Non-Catalytic Reduction(SNCR), environmental coal, Multi-criteria decision-making(MCDM)

Management of big wildlife such as bears can be a difficult task, especially in the face of human-wildlife conflict and demands of the hunting industry. The Brown Bear (Ursus arctos) population at Yusufeli County (Artvin, northeastern Turkey) has recently been the focus of scientific, social and economic concerns. This study population of c. 140 individuals occurs within 800 km2 of forested and alpine land. Legal hunting of male bears was allowed in 2007 after an interval of four years. This study aims to find out through a population viability analysis the level and frequency of trophy hunting this population can tolerate for the next 50 years. A matrix model with six age-classes for each sex was constructed using observed and literature-based parameter values. RAMAS Metapop was used to simulate four different scenarios where numbers of hunted bears and hunting frequency changes. The model was highly sensitive to maximum growth rate and adult survival. Interval extinction probabilities for the next 50 years ranged between 0% and 26% depending on the scenario. Viable scenarios (with an extinction probability &lt / 0.05) were only possible with either no trophy hunting or hunting of 4 subadult/adult males and 1 adult female every other year. Legal and illegal hunting jointly impact the bear population in a strong way, and when they occur simultaneously every year, they lead to extinction in the long run. Avoidance of illegal killing and a close supervision of trophy hunting are crucial in the management of this bear population.

Rapid prototyping methods embrace a family of manufacturing methods that are developed to speed up the prototyping stage of product design. The sole needed input for production being the solid model of the part, mold/tool-free production characteristics and the geometric part complexity that can be achieved due to layer-by-layer production have extended the applicability/research areas of these methods beyond prototyping. Local pore formation in part that occurs as a result of the discrete manufacturing nature of rapid prototyping methods can be viewed as an opportunity for material development. In this thesis, the manufacturing-internal (porous) structure-mechanical property relations of porous materials are investigated. These porous parts are produced via Selective Laser Sintering (SLS) which is a rapid prototyping method. The elastic modulus, tensile strength, rupture strength and Poisson&rsquo / s ratio of uniform porous specimens with known porosities are determined through standardized mechanical tests for polymeric materials. The mechanical property variation profiles in graded materials are determined using the mechanical properties of uniform parts. The mechanical behavior of uniform and graded materials under applied loads are modeled using finite element method and simulation results are compared to the results of mechanical tests performed on graded materials. In addition, feasibility of producing resin filled composite parts from these uniform and graded porous parts are sought. Porous parts (both uniformly and graded) that are infiltrated with epoxy resin have been characterized mechanically and the results have been compared with the uninfiltrated porous parts.

Selective laser sintering is a rapid prototyping method (RP), which was originally developed, along with other RP methods, to speed up the prototyping stage of product design. The sole needed input for production being the solid model of the part, the mold/tool-free production characteristics and the geometric part complexity that can be achieved due to layer-by-layer production have extended the applicability/research areas of these methods beyond prototyping towards new applications and material development. Local pore formation in a part that occurs as a result of the discrete manufacturing nature of selective laser sintering is normally considered a defect. In the current research, this is viewed as an opportunity for material development: Exploitation of rapid prototyping methods to produce composites/functionally graded materials with controlled porous structures. That the material interior structure (porous structure) and exterior shape are formed during the same course renders selective laser sintering process as an attractive manufacturing alternative for producing complex-geometry composite/porous materials, which may be difficult or impossible to manufacture with other techniques. In this thesis, the use of selective laser sintering (a rapid prototyping method) in producing uniformly porous and graded polymeric graded porous structures is studied. The material used was polyamide powder (PA 2200) and the selective laser sintering machine used was the EOSINT P 380 system. In this research, three process parameters of the SLS system, the hatching distance, the laser power and the laser scanning speed were varied to produce parts that have different porosities. Porous parts with a homogenous porous microstructure (uniformly porous parts) could be produced, as well as graded porous parts. The results of uniformly porous structure production were utilized to build graded porous structures by imparting different porosities along a certain direction within a single part. Both, uniformly porous and graded structures were characterized physically and mechanically. The porous parts (both uniformly porous and graded porous) were infiltrated with epoxy resin to produce epoxy-PA composites and graded materials. The physical and mechanical properties of these parts were compared with those of the uninfiltrated (porous PA) structures

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In this work, the steady-state performance of zeolite-based (Cu-ZSM-5) and vanadium-based honeycomb monolith catalysts was investigated in the selective catalytic reduction process (SCR) for NO removal using NH3. The aim was to delineate the effect of various parameters including pretreatment of the catalyst sample with H2, NH3-to-NO ratio, inlet oxygen concentration, and space velocity. The concentrations of the species (e.g. NO, NH3, and others) were determined using a Fourier Transform Infrared (FTIR) spectrometer. The temperature was varied from ambient (25 C) to 500 C. The investigation showed that all of the above parameters (except pre-treatment with H2) significantly affected the peak NO reduction, the temperature at which peak NO reduction occurred, and residual ammonia left at higher temperatures (also known as 'NH3 slip'). Depending upon the particular values of the parameters, a peak NO reduction of around 90% was obtained for both the catalysts. However, an accompanied generation of N2O and NO2 species was observed as well, being much higher for the vanadium-based catalyst than for the Cu-ZSM-5 catalyst. For both catalysts, the peak NO reduction decreased with an increase in space velocity, and did not change significantly with an increase in oxygen concentration. The temperatures at which peak NO reduction and complete NH3 removal occurred increased with an increase in space velocity but decreased with an increase in oxygen concentration. The presence of more ammonia at the inlet (i.e. higher NH3-to-NO ratio) improved the peak NO reduction but simultaneously resulted in an increase in residual ammonia. Pretreatment of the catalyst sample with H2 (performed only for the Cu-ZSM-5 catalyst) did not produce any perceivable difference in any of the results for the conditions of these experiments.

Two flow reactor studies, using an electrically heated laminar flow reactor over Vanadia based (V2O5-WO3/TiO2) honeycomb catalyst, were performed at 1 atm pressure and various temperatures. The experiments were conducted using simulated exhaust gas compositions for different exhaust gases. A quartz tube was used in order to establish inert conditions inside the reactor. The experiments utilized a Fourier transform infrared (FTIR) spectrometer in order to perform both qualitative and quantitative analysis of the reaction products. Urea-water solution decomposition was investigated over V2O5-WO3/TiO2 catalyst over the entire SCR temperature range using the temperature controlled flow reactor. The solution was preheated and then injected into pure nitrogen (N2) stream. The decomposition experiments were conducted with a number of oxygen (O2) compositions (0, 1, 10, and 15%) over the temperature range of 227oC to 477oC. The study showed ammonia (NH3), carbon-dioxide (CO2) and nitric oxide (NO) as the major products of decomposition along with other products such as nitrous oxide (N2O) and nitrogen dioxide (NO2). The selective catalytic reduction (SCR) of nitric oxide (NO) with urea-water solution over V2O5-WO3/TiO2 catalyst using a laboratory laminar-flow reactor was investigated. Urea-water solution was injected at a temperature higher than the vaporization temperature of water and the flow reactor temperature was varied from 127oC to 477oC. A FTIR spectrometer was used to determine the concentrations of the product species. The major products of SCR reduction were NH3, NO and CO2 along with the presence of other minor products NO2 and N2O. NO removal of up to 87% was observed. The aim of the urea-water decomposition experiments was to study the decomposition process as close to the SCR configuration as possible. The aim of the SCR experiments was to delineate the effect of various parameters including reaction temperature and O2 concentration on the reduction process. The SCR investigation showed that changing parameter values significantly affected the NO removal, the residual NH3 concentration, the temperature of the maximum NO reduction, and the temperature of complete NH3 conversion. In the presence of O2, the reaction temperature for maximum NO reduction was 377?C for ratio of 1.0.

Wireless data broadcast is an efficient way to disseminate digital information to clients equipped with mobile devices. It allows a huge number of the mobile clients simultaneously access data at anytime and anywhere in the wireless environments. Applications using wireless data broadcast to disseminate information include accessing stock activities and traffic conditions. Using index technologies on the broadcast file, i.e., selective tuning, can reduce a lot of energy consumption of the mobile devices without significantly increasing client waiting time. Most of the research work for selective tuning assumes that each data item broadcast on the wireless channel is fairly evenly accessed by mobile clients. In real-life applications, more popular data may be frequently accessed by clients than less popular ones, i.e., skewed access patterns. In this dissertation, to support efficiently selective tuning with skewed access patterns in the single-channel wireless environments, we first propose a skewed distributed index, SDI, on the uniform data broadcast, on which each data item is broadcast once in a broadcast cycle. Second, we propose a skewed index, SI, on the nonuniform data broadcast, on which a few popular data items are broadcast more frequently in a broadcast cycle than the others. The first proposed algorithm, SDI, considers the access probabilities of data items and the replication of index nodes. The proposed algorithm traverses a balanced tree to determine whether an index node should be replicated by considering the access probability of its child node. In our performance analysis and simulation results, we have shown that our proposed algorithm outperforms the variant-fanout tree index and the distributed index. The second proposed algorithm, SI, applies Acharya et al.'s Broadcast Disks to generate a broadcast program, in which the popular data items are broadcast more times than the others, in order to reduce client waiting time. Moreover, the proposed algorithm builds a skewed tree for these data items and allocates index nodes for the popular data items more times than those for the less popular ones in a broadcast cycle. From our performance analysis and simulation results, we have shown that our proposed SI outperforms the flexible index and the flexible distributed index.