Master of Science / Department of Mechanical and Nuclear Engineering / Liang-Wu Cai / The study on artificially created materials has much evidence of naval properties. Phononic Crystals (PCs) are new class of artificially constructed materials. They have a large number of scattering inclusions that are embedded in a homogeneous host material. These scatterers are arranged in periodic lattice structures. The scatterers and host materials are usually either solids or fluids. Phononic materials are useful due to their ability to hinder the existence of certain frequencies over which the propagation of elastic and acoustic waves are forbidden. The formation of phononic band gaps (PBGs) in PCs is determined by the material properties and the geometry of the periodic lattice structures. Some PCs have full band gaps [14, 55] while others have partial band gaps [35]. Although the study of PCs is an attractive area for many researchers, the investigations on PCs are just emerging. The aim of the thesis is to study on perform fabrication and experimental characterization of 2-D PCs having eccentrically layered scatterers. In addition, the influence of the eccentricity of the layered scatterers on the amplitude spectrums are experimentally observed. Hence, the main objective in this work is to characterize the influence of the eccentricity orientation angles on the transmitted amplitude spectra. The layered scatterers were created by inserting the paraffin-coated stainless steel rods into the cavities. Two sets of stainless steel rod diameters (2 mm and 2.5 mm) were used. The eccentricity orientation angles of scatterers were changed from 0 degree to 90 degrees at the increment of 22.5 degrees. Ultrasonic waves were introduced into the test pieces to observe the propagated waves through the material. The ultrasonic Through Transmission Test (TTT) followed by signal processing techniques was employed to produce the transmitted spectra of PCs. The frequency dependent amplitude spectrums were observed at the chosen frequency ranges with the help of MATLAB and Fast Fourier Transformation (FFT) function. The results show that the geometry and the material parameters change the attenuation of amplitudes by hindering the wave propagation. This leads PC as a good candidate for a sound barrier for controlling the wave propagation or vibrations within the chosen frequency ranges. Keywords: Phononic Crystal/s (PC or PCs); Phononic Band Gap/s (PBG or PBGs); Through Transmission Test (TTT), Fast Fourier Transformation (FFT), Square array, Triangular array, Amplitude spectrum/ Spectra, Eccentrically layered scatterers

Over the last three centuries the rapidly increasing influence of technology has come to dominate every aspect of human life. Progressive realization of adverse effects has led to increasing demand for and imposition of control measures. The concept of common law embodied in legal tradition have been found inadequate, and forced a change to "enacted law". The regulatory explosion necessitated delegation from legislative to executive agencies.The resulting techniques of control developed in the United Kingdom, New Zealand, Australia, Canada and the United States are examined. One common factor stands out, the extensive dependence of law-making bodies on independent technical specification material from non-government sources, and the confused, conflicting, and inconsistent methods of utilizing those specifications in law-making. Most of this independent material comes from Standards bodies. Their basic concept, the establishing of acceptable practice by prior agreement, is outlined, and the growth of the movement traced from the original development in Britain to a World-wide movement. Their processes of consultation and consensus represent a practical democratic system of self regulation. Studies of these aspects are rare, but a number of those relevant are reviewed, ranging from the Robens committee in Britain, through Building Code Reform in New Zealand, to a whole series of very recent reports from the United States, including a Presidential Task Force, an attempt to establish a National Standards Policy, a Federally commissioned study by a Professor of Law, and a Presidential Executive Order.From these emerge the pattern of complaint: Regulatory control is excessive, rigid, and liable to cause economic waste. It tends to be ineffective, and fails to achieve primary aims. As technology development exposes society to greater risks, efficiency becomes more vital, and failure to achieve control a serious danger. Problems arise from the failure of traditional legal approaches to adapt to the newer challenge of technology, particularly the legal acceptance of law "as it is" without recognition that the task calls for developing the law-making process to meet the needs of the changed situation. It is contended that many of the problems in regulatory control of technology come from the practice of making technical specification material direct legal command. The various reports reviewed comment on the limitations inherent in negative legislative control, the irrelevance of litigation, Court action and punishment, to the fundamental problem of achieving successful control. There is need for the encouragement of self regulation, and establishment of appropriate links with law.The special characteristics and responsibilities of law controlling technology are brought out, and call for identification as a separate branch of law: "Technological Law". Such law, it is contended, needs to make optimum usage of (a) the factors that have contributed to the dominance of technology, including the scientific approach, and the practice of prior agreement and (b) the essential components of democratic society, including participation, consensus, decentralized control, and self regulation associated with a formal method of determining acceptability.Practical proposals are developed involving the recognition of the practice of legislating by reference to independent technical specifications the encouragement of self-regulation processes through statutory backing, and their linking by recognition of the dyad in law, a separation of fundamental aims and principles appropriate to law from the means of meeting these aims.There is detailed examination of the three themes of reform. Techniques of the reference process, the legal objections, and the range of practices are examined, and acceptable technique suggested. The significance and importance of self-regulation is examined, and the contribution of "Standards" developed. A detailed examination is made of the various examples of two part law found in legislation, or in the studies reviewed. The framing of law in terms of general requirements is considered in relation to the problem of certainty and the idealization of the performance concept. The prerogative of the law-maker to designate certain practices as complying with general requirements is established as fundamental. The objection that this is a function of interpretation which lies exclusively with the Courts is discussed and the principle advanced that the vital Court function should never be called into the routine observance area.Technological law has as its essential aim the achievement of observance. Punishment, and court action is indication of failure. The emphasis must be on understanding and facilitating compliance. The second part of the dyad calls for sets of interrelated, interdependent specifications of acceptable practice, serving equally differing specialized laws, technical practices, commercial practices and education, and clarifying in positive fashion that which complies with law. The existing, established mechanisms of the world Standards movement are seen as providing the sets of technical specifications to fulfill this second function. This industry-developed process of self regulation utilises the techniques of prior agreement and in practical form, the elusive concept of consensus.Studies have emphasised the superior ability of the system to call in technical resources and voluntary effort to the service of law-making, in comparison with the resources of a governmental agency. The desirable aim is partnership, and the utilization of substantial measures of voluntary compliance.The question of recognition and authority for Standards and their producing organizations is seen as essential, and criteria are developed from the examples reviewed, notably from the pioneer New Zealand Act of 1941.The study emphasizes the little recognised function of Standards organizations of identifying acceptable practice, providing what has become an essential component of the machinery of government of a modern state.The mechanism provides a basis of certainty for commercial operations, and, through the strength of consumer or purchaser choice, an effective method of control as an alternative to yet more complex regulatory activity.

Over the last three centuries the rapidly increasing influence of technology has come to dominate every aspect of human life. Progressive realization of adverse effects has led to increasing demand for and imposition of control measures. The concept of common law embodied in legal tradition have been found inadequate, and forced a change to "enacted law". The regulatory explosion necessitated delegation from legislative to executive agencies.The resulting techniques of control developed in the United Kingdom, New Zealand, Australia, Canada and the United States are examined. One common factor stands out, the extensive dependence of law-making bodies on independent technical specification material from non-government sources, and the confused, conflicting, and inconsistent methods of utilizing those specifications in law-making. Most of this independent material comes from Standards bodies. Their basic concept, the establishing of acceptable practice by prior agreement, is outlined, and the growth of the movement traced from the original development in Britain to a World-wide movement. Their processes of consultation and consensus represent a practical democratic system of self regulation. Studies of these aspects are rare, but a number of those relevant are reviewed, ranging from the Robens committee in Britain, through Building Code Reform in New Zealand, to a whole series of very recent reports from the United States, including a Presidential Task Force, an attempt to establish a National Standards Policy, a Federally commissioned study by a Professor of Law, and a Presidential Executive Order.From these emerge the pattern of complaint: Regulatory control is excessive, rigid, and liable to cause economic waste. It tends to be ineffective, and fails to achieve primary aims. As technology development exposes society to greater risks, efficiency becomes more vital, and failure to achieve control a serious danger. Problems arise from the failure of traditional legal approaches to adapt to the newer challenge of technology, particularly the legal acceptance of law "as it is" without recognition that the task calls for developing the law-making process to meet the needs of the changed situation. It is contended that many of the problems in regulatory control of technology come from the practice of making technical specification material direct legal command. The various reports reviewed comment on the limitations inherent in negative legislative control, the irrelevance of litigation, Court action and punishment, to the fundamental problem of achieving successful control. There is need for the encouragement of self regulation, and establishment of appropriate links with law.The special characteristics and responsibilities of law controlling technology are brought out, and call for identification as a separate branch of law: "Technological Law". Such law, it is contended, needs to make optimum usage of (a) the factors that have contributed to the dominance of technology, including the scientific approach, and the practice of prior agreement and (b) the essential components of democratic society, including participation, consensus, decentralized control, and self regulation associated with a formal method of determining acceptability.Practical proposals are developed involving the recognition of the practice of legislating by reference to independent technical specifications the encouragement of self-regulation processes through statutory backing, and their linking by recognition of the dyad in law, a separation of fundamental aims and principles appropriate to law from the means of meeting these aims.There is detailed examination of the three themes of reform. Techniques of the reference process, the legal objections, and the range of practices are examined, and acceptable technique suggested. The significance and importance of self-regulation is examined, and the contribution of "Standards" developed. A detailed examination is made of the various examples of two part law found in legislation, or in the studies reviewed. The framing of law in terms of general requirements is considered in relation to the problem of certainty and the idealization of the performance concept. The prerogative of the law-maker to designate certain practices as complying with general requirements is established as fundamental. The objection that this is a function of interpretation which lies exclusively with the Courts is discussed and the principle advanced that the vital Court function should never be called into the routine observance area.Technological law has as its essential aim the achievement of observance. Punishment, and court action is indication of failure. The emphasis must be on understanding and facilitating compliance. The second part of the dyad calls for sets of interrelated, interdependent specifications of acceptable practice, serving equally differing specialized laws, technical practices, commercial practices and education, and clarifying in positive fashion that which complies with law. The existing, established mechanisms of the world Standards movement are seen as providing the sets of technical specifications to fulfill this second function. This industry-developed process of self regulation utilises the techniques of prior agreement and in practical form, the elusive concept of consensus.Studies have emphasised the superior ability of the system to call in technical resources and voluntary effort to the service of law-making, in comparison with the resources of a governmental agency. The desirable aim is partnership, and the utilization of substantial measures of voluntary compliance.The question of recognition and authority for Standards and their producing organizations is seen as essential, and criteria are developed from the examples reviewed, notably from the pioneer New Zealand Act of 1941.The study emphasizes the little recognised function of Standards organizations of identifying acceptable practice, providing what has become an essential component of the machinery of government of a modern state.The mechanism provides a basis of certainty for commercial operations, and, through the strength of consumer or purchaser choice, an effective method of control as an alternative to yet more complex regulatory activity.

Over the last three centuries the rapidly increasing influence of technology has come to dominate every aspect of human life. Progressive realization of adverse effects has led to increasing demand for and imposition of control measures. The concept of common law embodied in legal tradition have been found inadequate, and forced a change to "enacted law". The regulatory explosion necessitated delegation from legislative to executive agencies.The resulting techniques of control developed in the United Kingdom, New Zealand, Australia, Canada and the United States are examined. One common factor stands out, the extensive dependence of law-making bodies on independent technical specification material from non-government sources, and the confused, conflicting, and inconsistent methods of utilizing those specifications in law-making. Most of this independent material comes from Standards bodies. Their basic concept, the establishing of acceptable practice by prior agreement, is outlined, and the growth of the movement traced from the original development in Britain to a World-wide movement. Their processes of consultation and consensus represent a practical democratic system of self regulation. Studies of these aspects are rare, but a number of those relevant are reviewed, ranging from the Robens committee in Britain, through Building Code Reform in New Zealand, to a whole series of very recent reports from the United States, including a Presidential Task Force, an attempt to establish a National Standards Policy, a Federally commissioned study by a Professor of Law, and a Presidential Executive Order.From these emerge the pattern of complaint: Regulatory control is excessive, rigid, and liable to cause economic waste. It tends to be ineffective, and fails to achieve primary aims. As technology development exposes society to greater risks, efficiency becomes more vital, and failure to achieve control a serious danger. Problems arise from the failure of traditional legal approaches to adapt to the newer challenge of technology, particularly the legal acceptance of law "as it is" without recognition that the task calls for developing the law-making process to meet the needs of the changed situation. It is contended that many of the problems in regulatory control of technology come from the practice of making technical specification material direct legal command. The various reports reviewed comment on the limitations inherent in negative legislative control, the irrelevance of litigation, Court action and punishment, to the fundamental problem of achieving successful control. There is need for the encouragement of self regulation, and establishment of appropriate links with law.The special characteristics and responsibilities of law controlling technology are brought out, and call for identification as a separate branch of law: "Technological Law". Such law, it is contended, needs to make optimum usage of (a) the factors that have contributed to the dominance of technology, including the scientific approach, and the practice of prior agreement and (b) the essential components of democratic society, including participation, consensus, decentralized control, and self regulation associated with a formal method of determining acceptability.Practical proposals are developed involving the recognition of the practice of legislating by reference to independent technical specifications the encouragement of self-regulation processes through statutory backing, and their linking by recognition of the dyad in law, a separation of fundamental aims and principles appropriate to law from the means of meeting these aims.There is detailed examination of the three themes of reform. Techniques of the reference process, the legal objections, and the range of practices are examined, and acceptable technique suggested. The significance and importance of self-regulation is examined, and the contribution of "Standards" developed. A detailed examination is made of the various examples of two part law found in legislation, or in the studies reviewed. The framing of law in terms of general requirements is considered in relation to the problem of certainty and the idealization of the performance concept. The prerogative of the law-maker to designate certain practices as complying with general requirements is established as fundamental. The objection that this is a function of interpretation which lies exclusively with the Courts is discussed and the principle advanced that the vital Court function should never be called into the routine observance area.Technological law has as its essential aim the achievement of observance. Punishment, and court action is indication of failure. The emphasis must be on understanding and facilitating compliance. The second part of the dyad calls for sets of interrelated, interdependent specifications of acceptable practice, serving equally differing specialized laws, technical practices, commercial practices and education, and clarifying in positive fashion that which complies with law. The existing, established mechanisms of the world Standards movement are seen as providing the sets of technical specifications to fulfill this second function. This industry-developed process of self regulation utilises the techniques of prior agreement and in practical form, the elusive concept of consensus.Studies have emphasised the superior ability of the system to call in technical resources and voluntary effort to the service of law-making, in comparison with the resources of a governmental agency. The desirable aim is partnership, and the utilization of substantial measures of voluntary compliance.The question of recognition and authority for Standards and their producing organizations is seen as essential, and criteria are developed from the examples reviewed, notably from the pioneer New Zealand Act of 1941.The study emphasizes the little recognised function of Standards organizations of identifying acceptable practice, providing what has become an essential component of the machinery of government of a modern state.The mechanism provides a basis of certainty for commercial operations, and, through the strength of consumer or purchaser choice, an effective method of control as an alternative to yet more complex regulatory activity.

Over the last three centuries the rapidly increasing influence of technology has come to dominate every aspect of human life. Progressive realization of adverse effects has led to increasing demand for and imposition of control measures. The concept of common law embodied in legal tradition have been found inadequate, and forced a change to "enacted law". The regulatory explosion necessitated delegation from legislative to executive agencies.The resulting techniques of control developed in the United Kingdom, New Zealand, Australia, Canada and the United States are examined. One common factor stands out, the extensive dependence of law-making bodies on independent technical specification material from non-government sources, and the confused, conflicting, and inconsistent methods of utilizing those specifications in law-making. Most of this independent material comes from Standards bodies. Their basic concept, the establishing of acceptable practice by prior agreement, is outlined, and the growth of the movement traced from the original development in Britain to a World-wide movement. Their processes of consultation and consensus represent a practical democratic system of self regulation. Studies of these aspects are rare, but a number of those relevant are reviewed, ranging from the Robens committee in Britain, through Building Code Reform in New Zealand, to a whole series of very recent reports from the United States, including a Presidential Task Force, an attempt to establish a National Standards Policy, a Federally commissioned study by a Professor of Law, and a Presidential Executive Order.From these emerge the pattern of complaint: Regulatory control is excessive, rigid, and liable to cause economic waste. It tends to be ineffective, and fails to achieve primary aims. As technology development exposes society to greater risks, efficiency becomes more vital, and failure to achieve control a serious danger. Problems arise from the failure of traditional legal approaches to adapt to the newer challenge of technology, particularly the legal acceptance of law "as it is" without recognition that the task calls for developing the law-making process to meet the needs of the changed situation. It is contended that many of the problems in regulatory control of technology come from the practice of making technical specification material direct legal command. The various reports reviewed comment on the limitations inherent in negative legislative control, the irrelevance of litigation, Court action and punishment, to the fundamental problem of achieving successful control. There is need for the encouragement of self regulation, and establishment of appropriate links with law.The special characteristics and responsibilities of law controlling technology are brought out, and call for identification as a separate branch of law: "Technological Law". Such law, it is contended, needs to make optimum usage of (a) the factors that have contributed to the dominance of technology, including the scientific approach, and the practice of prior agreement and (b) the essential components of democratic society, including participation, consensus, decentralized control, and self regulation associated with a formal method of determining acceptability.Practical proposals are developed involving the recognition of the practice of legislating by reference to independent technical specifications the encouragement of self-regulation processes through statutory backing, and their linking by recognition of the dyad in law, a separation of fundamental aims and principles appropriate to law from the means of meeting these aims.There is detailed examination of the three themes of reform. Techniques of the reference process, the legal objections, and the range of practices are examined, and acceptable technique suggested. The significance and importance of self-regulation is examined, and the contribution of "Standards" developed. A detailed examination is made of the various examples of two part law found in legislation, or in the studies reviewed. The framing of law in terms of general requirements is considered in relation to the problem of certainty and the idealization of the performance concept. The prerogative of the law-maker to designate certain practices as complying with general requirements is established as fundamental. The objection that this is a function of interpretation which lies exclusively with the Courts is discussed and the principle advanced that the vital Court function should never be called into the routine observance area.Technological law has as its essential aim the achievement of observance. Punishment, and court action is indication of failure. The emphasis must be on understanding and facilitating compliance. The second part of the dyad calls for sets of interrelated, interdependent specifications of acceptable practice, serving equally differing specialized laws, technical practices, commercial practices and education, and clarifying in positive fashion that which complies with law. The existing, established mechanisms of the world Standards movement are seen as providing the sets of technical specifications to fulfill this second function. This industry-developed process of self regulation utilises the techniques of prior agreement and in practical form, the elusive concept of consensus.Studies have emphasised the superior ability of the system to call in technical resources and voluntary effort to the service of law-making, in comparison with the resources of a governmental agency. The desirable aim is partnership, and the utilization of substantial measures of voluntary compliance.The question of recognition and authority for Standards and their producing organizations is seen as essential, and criteria are developed from the examples reviewed, notably from the pioneer New Zealand Act of 1941.The study emphasizes the little recognised function of Standards organizations of identifying acceptable practice, providing what has become an essential component of the machinery of government of a modern state.The mechanism provides a basis of certainty for commercial operations, and, through the strength of consumer or purchaser choice, an effective method of control as an alternative to yet more complex regulatory activity.

Over the last three centuries the rapidly increasing influence of technology has come to dominate every aspect of human life. Progressive realization of adverse effects has led to increasing demand for and imposition of control measures. The concept of common law embodied in legal tradition have been found inadequate, and forced a change to "enacted law". The regulatory explosion necessitated delegation from legislative to executive agencies.The resulting techniques of control developed in the United Kingdom, New Zealand, Australia, Canada and the United States are examined. One common factor stands out, the extensive dependence of law-making bodies on independent technical specification material from non-government sources, and the confused, conflicting, and inconsistent methods of utilizing those specifications in law-making. Most of this independent material comes from Standards bodies. Their basic concept, the establishing of acceptable practice by prior agreement, is outlined, and the growth of the movement traced from the original development in Britain to a World-wide movement. Their processes of consultation and consensus represent a practical democratic system of self regulation. Studies of these aspects are rare, but a number of those relevant are reviewed, ranging from the Robens committee in Britain, through Building Code Reform in New Zealand, to a whole series of very recent reports from the United States, including a Presidential Task Force, an attempt to establish a National Standards Policy, a Federally commissioned study by a Professor of Law, and a Presidential Executive Order.From these emerge the pattern of complaint: Regulatory control is excessive, rigid, and liable to cause economic waste. It tends to be ineffective, and fails to achieve primary aims. As technology development exposes society to greater risks, efficiency becomes more vital, and failure to achieve control a serious danger. Problems arise from the failure of traditional legal approaches to adapt to the newer challenge of technology, particularly the legal acceptance of law "as it is" without recognition that the task calls for developing the law-making process to meet the needs of the changed situation. It is contended that many of the problems in regulatory control of technology come from the practice of making technical specification material direct legal command. The various reports reviewed comment on the limitations inherent in negative legislative control, the irrelevance of litigation, Court action and punishment, to the fundamental problem of achieving successful control. There is need for the encouragement of self regulation, and establishment of appropriate links with law.The special characteristics and responsibilities of law controlling technology are brought out, and call for identification as a separate branch of law: "Technological Law". Such law, it is contended, needs to make optimum usage of (a) the factors that have contributed to the dominance of technology, including the scientific approach, and the practice of prior agreement and (b) the essential components of democratic society, including participation, consensus, decentralized control, and self regulation associated with a formal method of determining acceptability.Practical proposals are developed involving the recognition of the practice of legislating by reference to independent technical specifications the encouragement of self-regulation processes through statutory backing, and their linking by recognition of the dyad in law, a separation of fundamental aims and principles appropriate to law from the means of meeting these aims.There is detailed examination of the three themes of reform. Techniques of the reference process, the legal objections, and the range of practices are examined, and acceptable technique suggested. The significance and importance of self-regulation is examined, and the contribution of "Standards" developed. A detailed examination is made of the various examples of two part law found in legislation, or in the studies reviewed. The framing of law in terms of general requirements is considered in relation to the problem of certainty and the idealization of the performance concept. The prerogative of the law-maker to designate certain practices as complying with general requirements is established as fundamental. The objection that this is a function of interpretation which lies exclusively with the Courts is discussed and the principle advanced that the vital Court function should never be called into the routine observance area.Technological law has as its essential aim the achievement of observance. Punishment, and court action is indication of failure. The emphasis must be on understanding and facilitating compliance. The second part of the dyad calls for sets of interrelated, interdependent specifications of acceptable practice, serving equally differing specialized laws, technical practices, commercial practices and education, and clarifying in positive fashion that which complies with law. The existing, established mechanisms of the world Standards movement are seen as providing the sets of technical specifications to fulfill this second function. This industry-developed process of self regulation utilises the techniques of prior agreement and in practical form, the elusive concept of consensus.Studies have emphasised the superior ability of the system to call in technical resources and voluntary effort to the service of law-making, in comparison with the resources of a governmental agency. The desirable aim is partnership, and the utilization of substantial measures of voluntary compliance.The question of recognition and authority for Standards and their producing organizations is seen as essential, and criteria are developed from the examples reviewed, notably from the pioneer New Zealand Act of 1941.The study emphasizes the little recognised function of Standards organizations of identifying acceptable practice, providing what has become an essential component of the machinery of government of a modern state.The mechanism provides a basis of certainty for commercial operations, and, through the strength of consumer or purchaser choice, an effective method of control as an alternative to yet more complex regulatory activity.

Master of Science / Department of Mechanical and Nuclear Engineering / Kirby S. Chapman / Oxides of nitrogen (NOx), carbon monoxide (CO) and other combustion by-products of gas turbines have long been identified as harmful atmospheric pollutants to the environment and humans. Various government agencies place restrictions on emissions and often require some sort of emissions monitoring even for new low emission gas turbines. Predicting actual emissions from operating parameters that affect the formation of pollutants, called parametric emissions monitoring system (PEMS), has potential economic advantages compared to a continuous emissions monitoring system (CEMS). The problem is that a simple applicable PEMS does not exist. During this study, a gas turbine combustor model applying first engineering principles was developed to predict the emission formation of NOx and CO in a gas turbine. The model is based on a lean-premixed combustor with a main and pilot burner including the function of a bleeding air valve. The model relies on ambient condition and load. The load is expressed as a percentage of the target speed of the gas producer turbine. Air flow and fuel flow for the main and pilot burner are calculated by the model based on the load through a set of measured input data for a specific gas turbine. To find the combustion temperature characteristics, the combustor is divided into several zones. The temperature for each zone is calculated by applying an energy balance. To predict NOx and CO, several correlations explored by various researchers are used and compared against each other, using the calculated temperatures, pressures and equivalence ratios. A comparison between collected emissions examples from a turbine test cell data spreadsheet and predicted emissions by the developed model under the same conditions show a highly accurate match for NOx emission at any load. Because of the high variation of CO at part load, the model predictions only match the CO data set at full load.

Master of Science / Department of Mechanical and Nuclear Engineering / Warren N. White / As energy efficient devices become more necessary, it is desired to increase the efficiency of air conditioning systems. Current systems use on/off control, where the unit primarily operates in the long lasting start up transients. A proposed solution is an air conditioning unit that runs continuously with active computer control implemented to maximize efficiency. The objective of this thesis is to develop a mathematical model for a specific air conditioning unit and to compare this model to measurements made on the specific unit. This model can then be used to develop a multi-input multi-output control law in the future. In this thesis, a linearized moving interface lumped parameter model is presented, and the derivation verified with great detail. The model predicts transient perturbations from a steady state operating point. The air conditioner tested in this work required several modifications including the addition of sensors and controllers. A description of the system is provided. Methods used to determine all of the parameters for the model are given with explanation. The model is simulated with computer software and compared with experimental data. Simulations predict the final value of superheat and pressures in the evaporator and condenser well for step changes in the compressor speed and expansion valve opening.

Doctor of Philosophy / Department of Mechanical and Nuclear Engineering / Kirby S. Chapman / The increasingly strict air emission regulations may require implementing Non-Selective Catalytic Reduction (NSCR) systems as a promising emission control technology for stationary rich burn spark ignition engines. Many recent experimental investigations that used NSCR systems for stationary natural gas fueled engines showed that NSCR systems were unable to consistently control the exhaust emissions level below the compliance limits. Part of this thesis is devoted to show the results from the field testing of three engines working in natural gas gathering stations located in the “Four Corners” area. These three engines are retrofitted with NSCR systems. Emissions and engine operating data were monitored for more than one year. Data collected from October 2007 through December 2008 shows significant variation in emissions levels over hours, days, and longer periods of time, as well as seasonal variations. As a result of these variations, simultaneous control of NOx and CO below the compliance limit was achieved less than fifty percent of the monitored time. Modeling of NSCR components to better understand, and then exploit, the underlying physical processes that occur in the lambda sensor and the catalyst media is now considered an essential step toward improving NSCR system performance. The second portion of this thesis focuses on modeling the lambda sensor that provides feedback to the air-to-fuel ratio controller. Correct interpretation of the sensor output signal is necessary to achieve consistently low emissions level. The goal of this modeling study is to improve the understanding of the physical processes that occur within the sensor, investigate the cross-sensitivity of various exhaust gas species on the sensor performance, and finally this model serves as a tool to improve NSCR control strategies. This model simulates the output from a planar switch type lambda sensor. The model consists of three modules. The first module models the multi-component mass transport through the sensor protective layer. Diffusion fluxes are calculated using the Maxwell-Stefan equation. The second module includes all the surface catalytic reactions that take place on the sensor platinum electrodes. All kinetic reactions are modeled based on the Langmuir-Hinshelwood kinetic mechanism. The third module is responsible for simulating the reactions that occur on the electrolyte material and determine the sensor output voltage. The details of these three modules as well as a parametric study that investigates the sensitivity of the output voltage signal to various exhaust gas parameters is provided in the thesis.

Master of Science / Department of Mechanical and Nuclear Engineering / Akira Tokuhiro / One of the most deadly tactics used by today’s terrorists is suicide bombing. Sensors have been developed and are being used in different situations to detect weapons and the people initiating suicide bombing attacks. The ideal detection technology would be fast, accurate, effective from long distances, and safe for the both detector and the object being detected. One detector that has shown potential as a tool for detecting hidden weapons is an infrared detector. Infrared detectors are passive sensors that create infrared, or thermal, images without having to expose the subject to any radiation. These images show the heat signature that is given off by objects of interest. Previous studies using infrared detectors for concealed weapon detection have tried to observe the image of the weapon. These have been largely unsuccessful, however, because infrared waves will not readily penetrate clothing. The research presented here determines the feasibility of modeling the heat signature produced by a suicide bomber using thermal models that predict the temperature of the exterior layers of clothing worn. The goal is to be able to compare the images acquired of the suspected bomber to the expected temperatures from the thermal models. If the presence of a hidden weapon affects the emitted heat signature to a point in which the clothing temperatures are not responding as predicted by a model, it is possible a detection system may be created using these models as a comparator and signal for detection. This research also determines a temperature range for which an operator viewing infrared images for suicide bomb detection may be relatively certain of the presence of a foreign object. Testing was also completed to determine those variables that affect an infrared image in ways that help or hinder the use of the thermal models in predicting the temperatures that appear in the infrared images.