The Internal Combustion Engines (ICEs) have played a significant role in transportation system to date and are expected to retain a significant market share through to 2050, according to the U.S. Energy Information Administration. Improving the efficiency of the ICEs is one of the most promising and cost-effective approaches to increasing highways vehicle’s fuel economy. The tools to address critical barriers to commercializing higher efficiency, lower emissions, advanced ICEs for passenger and commercial vehicles are increasingly important in the rapidly evolving automotive sector. In this research, a model based optimization strategy is developed for trade-off analysis of parts in Spark Ignition Internal Combustion Engines (SI-ICE). The trade-off analysis tool has been used as a complement to engine mapping to determine the operating region of an engine where a new part could lead to improvements in fuel efficiency, performance, and emissions. To build the engine models, a Design of Experiment (DoE) was developed for performing the engine tests. For each spark plug set, the engine tests were conducted twice with an acceptable control of the parameters that affect engine outputs. The engine torque, Break Specific Fuel Consumption (BSFC) and break specific NOx emission were considered as the engine responses. Engine models were built according to the two-stage modeling strategy by means of black box modeling techniques. The accuracies of the models were 96%, 95% and 92% for the engine torque, BSFC and NOx outputs respectively. For the optimization part, determination of the optimal spark timing for each spark plug was formulated as a multi-objective optimization problem searching for compromises among opposing objectives, i.e. engine torque, emission and fuel consumption. The optimization outputs were in form of Pareto fronts, enabling the selection of the best solutions in terms of different objectives by considering the higher level information. The resulted Pareto fronts of the two spark plugs were compared at different operating points of the Ford Coyote engine and results showed that the two plugs are comparable. The marginal difference was at low load and low speed condition, where the newly designed spark plug was better than the conventional design. / Thesis / Master of Applied Science (MASc)

This thesis discusses 'Modeler's Assistant', an interactive graphics tool which aids in the rapid development of VHDL models. The tool provides modeling, test bench generation, simulation, synthesis and validation features. The 'Process Model graph' which has representations for the concurrent processes is used as the basis for Modeler's Assistant. Test generation environment is integrated into the tool. A range of test bench options are provided to the user. The tool interfaces to 'Synopsys' VHDL analyzer, graphics debugger and synthesis tools. Validation of the behavioral model versus the synthesized structural model is also discussed. A detailed programming manual with many examples is provided for the benefit of the user. / Master of Science

The chemiluminescent species CH* and OH* are studied in premixed methane combustion to investigate the possible application of their light emissions in gas turbine combustion monitoring systems. The interpretation of integrated and local chemiluminescence measurements are shown to give important qualitative insights into the burning process. The formation path of OH* chemiluminescence is clarified and an accurate chemical kinetic model predicting OH* chemiluminescence emission is developed using GRIMECH 3.0 as a starting point for methane oxidation. CH* chemiluminescence is also modeled but difficulties in obtaining quenching data make the modeling efforts somewhat less successful than that for OH* chemiluminescence. Two combustion models are developed. The first is a semi-empirical model for a Bunsen type flame. The second is a 1-D model for a ceramic honeycomb flat-flame burner using the full chemical kinetics description of the conversion from fuel to products along with a detailed energy equation, accounting for the radiation energy exchange between hot gases and the honeycomb burner ceramic. The results of the modeling calculations show that OH* is superior to CH* chemiluminescence in terms of indicating heat-release rate. The formation of the ratio between CH* and OH* chemiluminescence is shown to be an accurate indicator of equivalence ratio. / Master of Science

The main purpose of this study was to compare the Distributed Engineering Workstation (DEW) and EPANET models. These two models are fundamentally different in the approaches taken to simulate hydraulic systems. To better understand the calculations behind each models' hydraulic simulation, three solution methods were evaluated and compared. The three solution approaches were the Todini, Hardy-Cross, and DEW bisection methods. The Todini method was included in the study because of its similarities to EPANET's hydraulic solution method and the Hardy-Cross solution was included due to its similarities with the DEW approach. Each solution method was used to solve a simple looped network, and the hydraulic solutions were compared. It was determined that all three solution methods predicted flow values that were very similar. A different, more complex looped network from the solution method comparison was simulated using both EPANET and DEW. Since EPANET is a well established water distribution system model, it was considered the standard for the comparison with DEW. The predicted values from the simulation in EPANET and DEW were compared. This comparison offered insight into the functionality of DEW's hydraulic simulation component. The comparison determined that the DEW model is sensitive to the tolerance value chosen for a simulation. The flow predictions between the DEW and EPANET models became much closer when the tolerance value in DEW was decreased. / Master of Science

The success of any product of Information Technology lies in its acceptance by the target audience. Several behavioral models have been formulated to analyze factors that affect human decisions to accept new technology while some technology is already in place. These models enable us to identify the areas of concern within the system and its environment and to address them. However, these models are based in industrial settings, and are more suited to situations when a person is introduced to the field of Information Technology. A separate stream of research tries to model the factors that cause an Information System, especially at the workplace, to be termed a success. No such models exist for the academic community and the Computer Science student community, in particular. In this thesis, the success of a new academic meta-search system for the Computer Science student community is measured and the extent to which various factors affect this success is identified. For this purpose, an Information System success model is composed with the help of models for technology acceptance and Digital Library quality metrics. The resultant model is then used to formulate a survey instrument and the results of a user study with this instrument are used to begin to validate this model. / Master of Science

Thermal Management of Electric Motors / Permanent Magnet Synchronous Motors (PMSMs) have garnered widespread adoption in electric vehicles owing to their exceptional characteristics, including high power density, robust torque capability, and superior efficiency compared to conventional electric motors. Implementing permanent magnets facilitates the absence of a heat source on the rotor side, contributing significantly to their exceptional performance. However, despite these advantages, the heightened vulnerability of permanent magnets necessitates rigorous thermal management and analysis for PMSMs, particularly during short-duration peak performances and steady-state continuous operations. Operating under such conditions can potentially adversely affect the permanent magnets, winding insulation, and overall motor performance. Therefore, addressing thermal concerns associated with PMSMs emerges as a critical endeavor. This research tackles these thermal challenges by employing a combined approach of Lumped Parameter Thermal Network (LPTN) and Computational Fluid Dynamics (CFD) for accurate and cost-effective thermal modeling. A CFD analysis is performed to analyze the effect of water jacket and oil splash cooling and to calculate the heat transfer coefficients resulting from these two methodologies. A conjugate heat transfer CFD model is used to analyze the water jacket with the aid of a multi-phase CFD model to simulate the effect of the oil splash on end-windings. CFD heat transfer coefficients are then integrated into an LPTN model to calculate the temperature distribution of the motor. Furthermore, a comparative analysis is used to show the difference between integrating CFD-derived heat transfer coefficients and the analytical heat transfer coefficients in the LPTN model. VI In summary, this research underscores the importance of effective thermal management in maximizing the performance and longevity of PMSMs in electric vehicles. By leveraging advanced modeling methodologies, it seeks to address the intricate thermal concerns associated with PMSMs, paving the way for significant advancements in electric vehicle technology and inspiring sustainable transportation solutions. / Thesis / Master of Applied Science (MASc) / Electric vehicles are crucial for the future of sustainable transportation, offering a cleaner alternative to conventional combustion-engine cars and helping reduce greenhouse gas emissions. Permanent Magnet Synchronous Motors (PMSMs) are key to their performance, providing high efficiency and power density. However, their effectiveness can be hindered by thermal issues, particularly during peak performance or continuous operation. This research addresses these thermal challenges by combining Lumped Parameter Thermal Network (LPTN) models with Computational Fluid Dynamics (CFD) simulations. By analyzing water jacket and oil splash cooling systems, the study calculates heat transfer coefficients and integrates these into the LPTN model to assess motor temperature distribution. The research highlights the critical role of effective thermal management in enhancing PMSM performance and longevity, aiming to advance electric vehicle technology and support sustainable transportation solutions.

We are living in a time of fundamental changes in the dynamic between privacy and surveillance. The ubiquity of information technology has changed the ways in which we interact, empowering us through new venues of communication and social intimacy. At the same time, it exposes us to the prying eyes of others, in the shape of governments, companies, or even fellow humans. This creates a challenging environment for the design of 'privacy-aware' applications, exacerbated by a disconnect between abstract knowledge of privacy and concrete information requirements of privacy design frameworks. In this work, we present a novel approach for the modeling of contextual privacy preference and practice. The process guides a 'privacy analyst' through the steps of evaluating, choosing, and deploying appropriate data collection strategies; the verification and validation of the collected data; and the systematic transformation of the dense, unstructured data into a structured domain model. We introduce the Privacy Domain Modeling Language (PDML) to address the representational needs of privacy domain models. Making use of the structure of PDML, we explore the applicability of the information theoretic concept 'entropy' to determine the completeness of the resulting model. We evaluate the utility of the process through its application to the evaluation and re-design of a web application for the management of students' directory information and education records. Through this case study, we demonstrate the potential for automation of the process through the Privacy Analyst Work eNvironment (PAWN) and show the process's seamless integration with existing privacy design frameworks. Finally, we provide evidence for the value of using entropy for determining model completeness, and provide an outlook on future work. / Ph. D.

Froth flotation is a separation process by which particles are selectively attached to air bubbles. It is one of the most dynamically complex industrial processes in use today. This complexity has steered research towards understanding the fundamental principles of the process. Relatively few researchers have successfully attempted to create a flotation simulator based on first principles. This thesis presents the development and testing of a simulator called SimuFloat, which is based on the flotation model developed at Virginia Tech. Flotation of chalcopyrite, coal, and phosphate are simulated. These simulations show the effects of changing the input parameters of the flotation circuit. The accuracy of SimuFloat is validated by comparing the predictions with the experimentally obtained flotation results. / Master of Science

With the increased prevalence of roundabouts in the United States, there is a need to evaluate the performance of roundabouts relative to other intersection control strategies. Few studies have compared roundabouts with other intersection control strategies in a systematic fashion. Consequently, this Thesis compares four types of intersection control strategies considering a single lane approach with a 58 km/hr speed limit and equal demand on all approaches. The study demonstrates that vehicle delay is minimized with the use of a roundabout intersection control for all demand levels below 500 veh/hr/approach. Above this point if the left turn percentage exceeds 70% traffic signal control is more efficient. The roundabout alternative also produces the fewest vehicle stops for low demand levels, low left turn demand and high right turn demand, however a TWSC alternative produces the least number of vehicle stops when the through and total demand is high. This study illustrates that fuel consumption and carbon dioxide, carbon monoxide, hydrocarbon and nitrogen oxide emissions can be improved with roundabout control over other intersection control strategies. The research presented here demonstrates that for low traffic demand levels roundabouts should be part of design alternatives considered for isolated intersection control. / Master of Science

Biological cells like any other material do conduct electricity. Though they come across as insulators, the resistance to the flow of current, i.e. impedance, could be used to characterize the cell itself. In this aspect, the impedance of cells can be a promising tool to investigate the state of the cell. A simple way of measuring the impedance would be a planar-microelectrode method. The cells are contained in culture medium while measurements are taken with micro-electrodes fabricated on top of a substrate. Since both the probe "tips" do not come in contact with the probed object, the impedance to be measured includes some components apart from that contributed by the cells. There have been publications reporting the usage of impedance of a cell to determine changes in the state of cells due to healing, drug candidate testing, functional genomic studies and so on. In this thesis, an effort has been made to measure the impedance of cells. Further, a component of the sensor, the passivation layer has been investigated for its contribution to the measured impedance in a quantitative manner. / Master of Science