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Title: Wide-band antenna design for use in minimal-scan, microwave tomographic imaging
Creator: Klaser, Jacob
Date: 2013
Collection: Electronic Theses & Dissertations
Description: Microwave tomography is widely used in biomedical imaging and nondestructive evaluation of dielectric materials. A novel microwave tomography system that uses an electrically-conformable mirror to steer the incident energy for producing multi-view projection data is being developed in the Non-Destructive Evaluation Laboratory (NDEL). Such a system will have a significant advantage over existing tomography systems in terms of simplicity of design and operation, particularly when there is...
Show moreMicrowave tomography is widely used in biomedical imaging and nondestructive evaluation of dielectric materials. A novel microwave tomography system that uses an electrically-conformable mirror to steer the incident energy for producing multi-view projection data is being developed in the Non-Destructive Evaluation Laboratory (NDEL). Such a system will have a significant advantage over existing tomography systems in terms of simplicity of design and operation, particularly when there is limited-access of the structure that is being imaged. The major components of a mirror-based tomography system are the source mirror assembly, and a receiver array for capturing the multi-view projection data. This thesis addresses the design and development of the receiver array. This imaging array features balanced, anti-podal Vivaldi antennas, which offer large bandwidth, high gain and a compact size. From the simulations, as well as the experimental results for the antenna, the return loss (S11) is below -10dB for the range from 2.2GHz to 8.2GHz, and the gain is measured to be near 6dB. The data gathered from the receiver array is then run through MATLAB code for tomographic reconstruction using the Filtered Back-Propagation algorithm from limited-view projections. Initial results of reconstruction from the measured data shows the feasibility of the approach, but a significant challenge remains in interpolating the data for a limited number of receiving antenna elements and removing noise from the reconstructed image.
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Title: What makes a space raced? : exploring writing centers as raced spaces
Creator: Faison, Wonderful
Date: 2018
Collection: Electronic Theses & Dissertations
Description: In this dissertation, What Makes a Spaced Raced?: Exploring Writing Centers as Raced Spaces, I interrogate the spatial design and object affect of the Writing Center and analyze how that design and object affect might effect those entering the Writing Center space. Because Writing Centers often position themselves as home or homelike spaces, the purpose of this project was to better understand (1) how Writing Center design may exclude marginalized bodies through its physical design and the...
Show moreIn this dissertation, What Makes a Spaced Raced?: Exploring Writing Centers as Raced Spaces, I interrogate the spatial design and object affect of the Writing Center and analyze how that design and object affect might effect those entering the Writing Center space. Because Writing Centers often position themselves as home or homelike spaces, the purpose of this project was to better understand (1) how Writing Center design may exclude marginalized bodies through its physical design and the various objects placed in the Writing Center, (2) how those exclusions are read by “outsiders” (those not working in the Writing Center space they critiqued), and (3) how Writing Centers can begin to design spaces that are read as more inclusive/accepting of marginalized bodies. By using Black womanism as both method and methodology, I designed comparative analysis of three Writing Centers in which tutors working in one Writing Center would interrogate a different Writing Center space. Using three Writing Center Sites, nine separate tutors—divided into groups of three—analyzed two separate sets photos of these three Writing Center sites. Participants analyzed both the unoccupied Writing Center Space and the occupied Writing Center to discern if the effect of a Writing Center space may be altered depending on who operates in the space. My findings indicate that race is read through a perception of class, e.g., the furniture, technology, and pictures/paintings participants marked as expensive suggested marginalized and working-class bodies would not seek tutoring services from or desire to be employed by the Writing Center.
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Title: Virtual officing trends in the practice of landscape architecture
Creator: Boyer, Douglas E.
Date: 2013
Collection: Electronic Theses & Dissertations
Description: This research examines trends in virtual officing in project-based organizations such as landscape architecture firms. Virtual officing is the process of employees conducting business full-time in designated places other than a central office. Of particular interest is the development of communications technology to allow these new business models to grow and prosper. A survey was distributed by the American Society of Landscape Architects to landscape architecture member firms, with...
Show moreThis research examines trends in virtual officing in project-based organizations such as landscape architecture firms. Virtual officing is the process of employees conducting business full-time in designated places other than a central office. Of particular interest is the development of communications technology to allow these new business models to grow and prosper. A survey was distributed by the American Society of Landscape Architects to landscape architecture member firms, with questions focusing on their business practices and virtual officing trends. It was found that virtual officing usage is on the rise in landscape architecture firms. Trends in hiring also were positively affected by the presence of virtual officing, showing a correlation between this new business model and the overall strength of a firm. -- Abstract.
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Title: Theoretical and numerical study of swirling flow separation devices for oil-water mixtures
Creator: Motin, Abdul
Date: 2015
Collection: Electronic Theses & Dissertations
Description: Oil-water separation is a critical aspect of produced water treatment, oil spill cleanup, and refining of petroleum products. Hydrocyclones are commonly used in these operations. A hydrocyclone is a device that separates two phases based on centrifugal forces acting on the two phases. Conventional hydrocyclones possess a finite turndown ratio and are effective for removing droplets greater than approximately ten microns. The understanding of hydrodynamic phenomena that limit the turndown...
Show moreOil-water separation is a critical aspect of produced water treatment, oil spill cleanup, and refining of petroleum products. Hydrocyclones are commonly used in these operations. A hydrocyclone is a device that separates two phases based on centrifugal forces acting on the two phases. Conventional hydrocyclones possess a finite turndown ratio and are effective for removing droplets greater than approximately ten microns. The understanding of hydrodynamic phenomena that limit the turndown ratio is crucial for improving hydrocyclone performance and finding a device that is reliable, efficient, and that has the potential to decrease the environmental footprint of oil and gas production. In this work, a quantitative understanding of the turndown ratio of an individual class hydrocyclone has been developed. A computational search is applied for redesigning the geometry of different modules of hydrocyclone. In addition, the desirable attributes of a crossflow filter and a vortex separator are combined into one unit to develop a crossflow filtration hydrocyclone (CFFH) for enhancing separation.The hydrodynamic characteristics of single and multiphase flows encountered in hydrocyclones, the trajectories of dispersed droplets, interaction of phases that involve breakup and coalescence of dispersed droplets, and the geometry and operating principles that characterize the performances of a hydrocyclone are investigated based on computational fluid dynamic (CFD) simulations using the Eulerian-Lagrangian, the Eulerian-Eulerian, and a coupled CFD-PBM (Population balance method) approaches. Results show that the finite turndown ratio in conventional hydrocyclones is a hydrodynamic effect that depends on the length of reverse flow core. Tailoring of hydrocyclone geometry with hyperbolic swirl chamber and new underflow outlet geometry significantly increases the separation efficiency and improves the turndown. Based on a parametric study, a novel hydrocyclone design is proposed that is able to achieve desired separation efficiency by a unit operation and possesses a large turndown. CFD studies were also performed on CFFH devices and showed that the swirl can aid in removing droplets from the membrane/filter surface.The novel hydrocyclone identified provides a stable reverse flow core for an increased range of feed Reynolds numbers and yields less energy loss. With increasing the feed Reynolds number, the novel hydrocyclone gradually decreases the cut size (a size of droplet having 50% separation efficiency); this does not appear in a conventional hydrocyclone. For the feed Reynolds number of 60,000, the cut size in the novel hydrocyclone is less than 10 microns whereas the conventional hydrocyclone has a cut size of 65 microns and is ineffective for droplet less than 10 microns.
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Title: The relationship of instructional method and occupational interests to the perception of proportion in the environment
Creator: Smith, Ruth Ann
Date: 1973
Collection: Electronic Theses & Dissertations

Title: The design of a high pressure fire system, Lansing, Michigan
Creator: Hirshman, George A.
Date: 1930
Collection: Electronic Theses & Dissertations

Title: The design of a bus terminal for Lansing, Mich
Creator: Edwards, William B.
Date: 1932
Collection: Electronic Theses & Dissertations

Title: The application and evaluation of a pilot study on the effect of a self-instructional unit concerning basic design principles for selected non-art majors
Creator: Yoder, Walter Donald, 1933-
Date: 1970
Collection: Electronic Theses & Dissertations

Title: Tenets of design for information exchange for boredom relief in passengers on long airport layovers using handheld devices
Creator: Gargeshwari, Malini Rao Raghunatha Rao
Date: 2001
Collection: Electronic Theses & Dissertations

Title: Targeting metabolic vulnerabilities in breast cancer subtypes
Creator: Ogrodzinski, Martin Peter
Date: 2020
Collection: Electronic Theses & Dissertations
Description: Breast cancer is a highly prevalent and deadly disease. Globally, it is the most diagnosed cancer in women and is responsible for the most cancer-related deaths among women. Breast cancer is also a remarkably heterogeneous disease, with clear variability in clinical parameters including histological presentation, receptor status, and gene expression patterns that differ between patients. A significant amount of effort has been spent characterizing breast cancer into subtypes, with the main...
Show moreBreast cancer is a highly prevalent and deadly disease. Globally, it is the most diagnosed cancer in women and is responsible for the most cancer-related deaths among women. Breast cancer is also a remarkably heterogeneous disease, with clear variability in clinical parameters including histological presentation, receptor status, and gene expression patterns that differ between patients. A significant amount of effort has been spent characterizing breast cancer into subtypes, with the main goal of improving patient outcomes by: 1) designing targeted therapies, and 2) improving our ability to determine patient prognosis. While scientists have made significant strides in meeting these goals, we still lack targeted therapies for some subtypes of breast cancer, and current therapies often fail to provide a lasting cure. Thus, additional research is needed to improve patient care. One promising area in breast cancer research is cancer metabolism. Using metabolism as a therapeutic target is rapidly gaining traction, as it is now widely appreciated that cancer cells exhibit significant differences in metabolism compared to normal cells. The primary goal of this dissertation is to study the metabolism of distinct subtypes of breast cancer and identify metabolic vulnerabilities that can be used to effectively treat each subtype.This thesis will begin with a review of current classification strategies for breast cancer subtypes and knowledge regarding subtype-specific metabolism. It will also consider modern techniques for targeting breast cancer metabolism for therapeutic benefit. Breast cancer heterogeneity and metabolism are investigated using cell lines and tumors derived from the MMTV-Myc mouse model, which mimics the complexity observed in human disease. Cell lines derived from two histologically defined subtypes, epithelial-mesenchymal transition (EMT) and papillary, are used to establish clear metabolic profiles for each subtype. Metabolic vulnerabilities are identified in glutathione biosynthesis and the tricarboxylic acid cycle in the EMT subtype and nucleotide biosynthesis is determined to be a metabolic weakness in the papillary subtype. It is further shown that pharmacologically targeting each of these metabolic pathways has the greatest effect on reducing proliferation when used against the vulnerable subtype. These in vitro findings are then expanded upon by integrating genomic and metabolomic data acquired from in vivo tumors. In vivo experiments reveal that the EMT and papillary tumors prefer parallel pathways to generate nucleotides, with the EMT subtype preferring to salvage nucleotides while the papillary subtype prefers to produce nucleotides de novo. CRISPR/Cas9 gene editing is used to functionally characterize the metabolic effects of targeting nucleotide salvage and de novo biosynthesis in the EMT and papillary subtypes, and determine that targeting the preferred pathway of each subtype is most effective at slowing tumor growth.Overall, this work demonstrates the power of using metabolism as a therapeutic target of breast cancer, and further shows that metabolic vulnerabilities specific to individual subtypes can be used effectively to guide personalized medicine.
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Title: System identification and control design for internal combustion engine variable valve timing systems
Creator: Ren, Zhen
Date: 2011
Collection: Electronic Theses & Dissertations
Description: Variable Valve Timing (VVT) systems are used on internal combustion engines so that they can meet stringent emission requirements, reduce fuel consumption, and increase output. Also, VVT plays a critical role in order for the engine to smoothly transit between spark ignition (SI) and homogeneous charge compression ignition (HCCI) combustion modes. In order to achieve these performance benefits and SI/HCCI transition, it is required that the VVT system be controlled accurately using a model...
Show moreVariable Valve Timing (VVT) systems are used on internal combustion engines so that they can meet stringent emission requirements, reduce fuel consumption, and increase output. Also, VVT plays a critical role in order for the engine to smoothly transit between spark ignition (SI) and homogeneous charge compression ignition (HCCI) combustion modes. In order to achieve these performance benefits and SI/HCCI transition, it is required that the VVT system be controlled accurately using a model based controller. This work studies hydraulic and electric VVT system modeling and controller design. The VVT system consists of electric, mechanical, and fluid dynamics components. Without knowledge of every component, obtaining physical-based models is not feasible. In this research, the VVT system models were obtained using system identification method. Limited by the sample rate of the crank-based camshaft position sensor, a function of engine speed, the actuator control sample rate is different from that of cam position sensor. Multi-rate system identification is a necessity for this application. On the other hand, it is also difficult to maintain the desired actuator operational condition with an open-loop control. Therefore, system identification in a closed-loop is required. In this study, Pseudo Random Binary Sequence (PRBS) q-Markov Cover identification is used to obtain the closed-loop model. The open-loop system model is calculated based on information of the closed-loop controller and identified closed-loop system model. Both open and closed-loop identifications are performed in a Hardware-In-the-Loop (HIL) simulation environment with a given reference model as a validation process. A hydraulic VVT actuator system test bench and an engine dynamometer (dyno) are used to conduct the proposed multi-rate system identification using PRBS as excitation signals. Output covariance constraint (OCC) controllers were designed based upon the identified models. Performance of the designed OCC controller was compared with those of the baseline proportional integral (PI) controller. Results show that the OCC controller uses less control effort and has less overshoot than those of PI ones. An electric VVT (EVVT) system with planetary gear system and local speed controller was modeled based on system dynamics. Simulation results of the EVVT system model provided a controller framework for the bench test. The EVVT system test bench was modified from the hydraulic VVT bench. Multi-rate closed-loop system identification was conducted on the EVVT system bench and a model based OCC controller was designed. The bench test results show that the OCC controller has a lower phase delay and lower overshoot than a tuned proportional controller, while having the same or faster response time. It is also observed that engine oil viscosity has a profound impact on the EVVT response time. The maximum response speed is saturated at a slow level if the viscosity is too high. From the bench and dyno tests, it is concluded that multi-rate closed-loop identification is a very effective way to retrieve controller design orientated VVT models. It is possible to use an OCC controller to achieve lower energy consumption, lower overshoot, and better tracking compared to PI and proportional controllers on both hydraulic and electric VVT systems.
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Title: Ring pack behavior and oil consumption modeling in ic engines
Creator: Ejakov, Mikhail Aleksandrovich
Date: 1998
Collection: Electronic Theses & Dissertations

Title: Reliable 5G system design and networking
Creator: Liang, Yuan (Graduate of Michigan State University)
Date: 2019
Collection: Electronic Theses & Dissertations
Description: The upcoming fifth generation (5G) system is expected to support a variety of different devices and applications, such as ultra-reliable and low latency communications, Internet of Things (IoT) and mobile cloud computing. Reliable and effective communications lie in the core of the 5G system design. This dissertation is focused on the design and evaluation of robust 5G systems under both benign and malicious environments, with considerations on both the physical layer and higher layers. For...
Show moreThe upcoming fifth generation (5G) system is expected to support a variety of different devices and applications, such as ultra-reliable and low latency communications, Internet of Things (IoT) and mobile cloud computing. Reliable and effective communications lie in the core of the 5G system design. This dissertation is focused on the design and evaluation of robust 5G systems under both benign and malicious environments, with considerations on both the physical layer and higher layers. For the physical layer, we study secure and efficient 5G transceiver under hostile jamming. We propose a securely precoded OFDM (SP-OFDM) system for efficient and reliable transmission under disguised jamming, a serious threat to 5G, where the jammer intentionally confuses the receiver by mimicking the characteristics of the authorized signal, and causes complete communication failure. We bring off a dynamic constellation by introducing secure randomness between the legitimate transmitter and receiver, and hence break the symmetricity between the authorized signal and the disguised jamming. It is shown that due to the secure randomness shared between the authorized transmitter and receiver, SP-OFDM can achieve a positive channel capacity under disguised jamming. The robustness of the proposed SP-OFDM scheme under disguised jamming is demonstrated through both theoretic and numerical analyses. We further address the problem of finding the worst jamming distribution in terms of channel capacity for the SP-OFDM system. We consider a practical communication scenario, where the transmitting symbols are uniformly distributed over a discrete and finite alphabet, and the jamming interference is subject to an average power constraint, but may or may not have a peak power constraint. Using tools in functional analysis and complex analysis, first, we prove the existence and uniqueness of the worst jamming distribution. Second, by analyzing the Kuhn-Tucker conditions for the worst jamming, we prove that the worst jamming distribution is discrete in amplitude with a finite number of mass points. For the higher layers, we start with the modeling of 5G high-density heterogeneous networks. We investigate the effect of relay randomness on the end-to-end throughput in multi-hop wireless networks using stochastic geometry. We model the nodes as Poisson Point Processes and calculate the spatial average of the throughput over all potential geometrical patterns of the nodes. More specifically, for problem tractability, we first consider the simple nearest neighbor (NN) routing protocol, and analyze the end-to-end throughput so as to obtain a performance benchmark. Next, note that the ideal equal-distance routing is generally not realizable due to the randomness in relay distribution, we propose a quasi-equal-distance (QED) routing protocol. We derive the range for the optimal hop distance, and analyze the end-to-end throughput both with and without intra-route resource reuse. It is shown that the proposed QED routing protocol achieves a significant performance gain over NN routing. Finally, we consider the malicious link detection in multi-hop wireless sensor networks (WSNs), which is an important application of 5G multi-hop wireless networks. Existing work on malicious link detection generally requires that the detection process being performed at the intermediate nodes, leading to considerable overhead in system design, as well as unstable detection accuracy due to limited resources and the uncertainty in the loyalty of the intermediate nodes themselves. We propose an efficient and robust malicious link detection scheme by exploiting the statistics of packet delivery rates only at the base stations. More specifically, first, we present a secure packet transmission protocol to ensure that except the base stations, any intermediate nodes on the route cannot access the contents and routing paths of the packets. Second, we design a malicious link detection algorithm that can effectively detect the irregular dropout at every hop (or link) along the routing path with guaranteed false alarm rate and low miss detection rate.
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Title: Rate allocation and QoS support in wireless mesh networks
Creator: Wang, Bo
Date: 2009
Collection: Electronic Theses & Dissertations

Title: Online teaching and faculty learning : the role of hypermedia in online course design
Creator: Knott, Jessica Lucille
Date: 2015
Collection: Electronic Theses & Dissertations
Description: Using semi-structured interviews, this study set out to explore how faculty experiences in reading, teaching, and technology inform their use of hyperlinks and hypermedia in online teaching, learning, and course design. Further, an exploration of how faculty learn new technologies as they develop their online courses serves as a lens through which to view course design and its evolution. Study findings reveal that the use of hypermedia in online course design reflects the reading preferences...
Show moreUsing semi-structured interviews, this study set out to explore how faculty experiences in reading, teaching, and technology inform their use of hyperlinks and hypermedia in online teaching, learning, and course design. Further, an exploration of how faculty learn new technologies as they develop their online courses serves as a lens through which to view course design and its evolution. Study findings reveal that the use of hypermedia in online course design reflects the reading preferences and practices of the faculty developing the course. Further, findings indicate that, even when formal faculty development programs are offered, faculty learning is extremely fluid, with heavy reliance upon the resources they can find easily and immediately as a means of learning new things. New teaching philosophies were rarely adopted, but new course structure elements and technologies were adopted if the faculty felt they would assist in the content delivery process. As a result, recommendations include the development of just-in-time resources for faculty, and the development of faculty development programs that allow for individualized assistance and transfer.
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Title: On the evolution of mutation bias in digital organisms
Creator: Rupp, Matthew
Date: 2011
Collection: Electronic Theses & Dissertations
Description: Mutation is one of the primary drivers of genetic change. In this work I study mutation biases, which are sets of different genetic-state inflow probabilities. Mutation biases have the potential to change the composition of genomes over time, leading to divergent short- and long-term evolutionary outcomes. I use digital organisms, self-replicating computer programs, to explore whether or not mutation biases are capable of altering the long-term adaptive behavior of populations; whether...
Show moreMutation is one of the primary drivers of genetic change. In this work I study mutation biases, which are sets of different genetic-state inflow probabilities. Mutation biases have the potential to change the composition of genomes over time, leading to divergent short- and long-term evolutionary outcomes. I use digital organisms, self-replicating computer programs, to explore whether or not mutation biases are capable of altering the long-term adaptive behavior of populations; whether mutation biases can be competitive traits; and whether mutation biases can evolve. I find that mutation biases can alter the long-term adaptive behavior of mutation bias-obligate populations in terms of both mean fitness and complex trait evolution. I also find that mutation biases can compete against one another under a variety of conditions, meaning mutation bias can selectable over relatively-short periods of time. The competitive success of a mutation bias does not always depend upon the presence of beneficial mutations, implicating an increase in the probability of neutral mutations as a sufficient mechanism for bias selection. Finally, I demonstrate that by giving organisms a mutable mutation bias allele, populations preferentially evolve to possess specific biases over others. Overall, this work shows that mutation bias can act as a selectable trait, influencing the evolution of populations with regard to both their internal-genetic and external environments.
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Title: Object location and shape estimation using a MIMO FMCW millimeter wave sensor
Creator: Lou, Yun
Date: 2018
Collection: Electronic Theses & Dissertations
Description: Autonomous systems such as self-driving cars and drones are going to transform our lives in many ways. One fundamental element of these systems is the accurate and robust sensing of the surrounding environments. Current solutions involve a multi-modal approach where varieties of sensors are utilized to achieve the best performance. Among all the sensing modalities, millimeter wave radar is playing a critical role due to its high resolution and the capability of sensing in the dark environment...
Show moreAutonomous systems such as self-driving cars and drones are going to transform our lives in many ways. One fundamental element of these systems is the accurate and robust sensing of the surrounding environments. Current solutions involve a multi-modal approach where varieties of sensors are utilized to achieve the best performance. Among all the sensing modalities, millimeter wave radar is playing a critical role due to its high resolution and the capability of sensing in the dark environment. As the cost, size and weight of millimeter wave radars decrease prominently in recent years, there is a significant opportunity to widely adopt it for a variety of sensing tasks.This thesis presents a MIMO FMCW millimeter wave radar system at 77-81 GHz band. It is a small-size and high-accuracy solution for sensing objects in the environment. Our system is designed to estimate the object's surface shape, orientation, curvature, boundaries, and 2D location by detecting the object's surface at multiple positions on a planned trajectory. We evaluated our system on a metal rectangular box and a metal cylinder. The experiment results show that our system is able to determine the surface type (planar or curved) correctly and achieve cm-level accuracy on the boundaries and location estimation. The orientation error is bounded to 2.14 degrees. The curvature estimation is highly accurate for the middle part of the curved surface.
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Title: Numerical simulation and modeling of compressor stage instability of a rotating stall nature
Creator: Vagani, Marco
Date: 2012
Collection: Electronic Theses & Dissertations
Description: Rotating stall is an unsteady flow phenomenon that appears in both axial and centrifugal compressors. It is detrimental to the performance of the compressor, significantly narrowing its operating range. Numerical simulation of this phenomenon has been a major area of investigation for axial compressors with some success. While stall occurs less often in centrifugal compressors than axial ones, it can be much harder to predict. Some preventive measures are known, but are mostly rules of thumb...
Show moreRotating stall is an unsteady flow phenomenon that appears in both axial and centrifugal compressors. It is detrimental to the performance of the compressor, significantly narrowing its operating range. Numerical simulation of this phenomenon has been a major area of investigation for axial compressors with some success. While stall occurs less often in centrifugal compressors than axial ones, it can be much harder to predict. Some preventive measures are known, but are mostly rules of thumb developed through experimental experience. Accurate modeling of rotating stall will allow for better understating of the onset conditions and possible preventive measures that may be adopted during the design stage, before testing.This work focuses on the prediction of impeller rotating stall using Computational Fluid Dynamics. A compressor was chosen that has demonstrated rotating stall instabilities with different diffuser lengths and return vanes. Unsteady numerical simulations were performed to establish the reliability with which rotating stall can be captured, as compared to the experimental results. Fast Fourier Transform analysis was used to determine the mass-flow fluctuations in the domain that can be associated to the phenomenon. These observations were then used to determine the onset flow rate for impeller rotating stall. Finally, a redesign of the compressor is proposed and analyzed using the developed methodology.
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Title: Natural landscaping, a comparison of design treatments in a surface mine setting
Creator: Wang, Lishuang
Date: 2013
Collection: Electronic Theses & Dissertations
Description: Planners, designers, scientists, and citizens are interested in rehabilitation, reclamation and protection of the post-mining environment. Consequently, a fair amount of research from scholars is focused on the technical aspects concerning the revegetation of the landscape and the science of reclamation; while only a small portion of the literature concerns planning and design. In this thesis, a case study in the Upper Peninsula of Michigan is used to explore post-ming treatments: abandoned...
Show morePlanners, designers, scientists, and citizens are interested in rehabilitation, reclamation and protection of the post-mining environment. Consequently, a fair amount of research from scholars is focused on the technical aspects concerning the revegetation of the landscape and the science of reclamation; while only a small portion of the literature concerns planning and design. In this thesis, a case study in the Upper Peninsula of Michigan is used to explore post-ming treatments: abandoned mine, resort development. a super hotel resot, and natural vegetation communities. The treatments (k=4) were evaluated with an environmental quality measure upon 10 images from each treatment (b=10). The results indicated that the resort and the natural community were best treatments, significantly better than the abandoned mine treatment (p<0.05). The super hotel was ranked as the third, which is less preferred than the two best treatments, but much better than the abandoned mine treatment (p<0.05). By identifying difference between each treatment, the results shows people have preference for natural environment and natural landscape is beautiful in their views.
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Title: Investigation of planar terahertz passive devices and coupling methods for on-wafer applications
Creator: Myers, Joshua Carl
Date: 2015
Collection: Electronic Theses & Dissertations
Description: In recent years, developments have pushed the cut-off frequencies of transistors near 1 THz, enabling for the first time the design of large bandwidth transmit/receive modules. While there has been a significant interest in the research community to implement these devices, many challenges have slowed such progress. Primarily, these challenges stem from the high dielectric and metal losses many materials display in the THz spectrum. However, to implement wafer-level integrated circuits in the...
Show moreIn recent years, developments have pushed the cut-off frequencies of transistors near 1 THz, enabling for the first time the design of large bandwidth transmit/receive modules. While there has been a significant interest in the research community to implement these devices, many challenges have slowed such progress. Primarily, these challenges stem from the high dielectric and metal losses many materials display in the THz spectrum. However, to implement wafer-level integrated circuits in the THz spectrum, efficient passive devices that are integration compatible must be developed. For any integrated system, many of the most important passive building blocks of the system are reduced to efficient waveguiding, filtering, and coupling between any active components, necessary measurement systems, and input sources. In this dissertation, efficient passive terahertz components, including waveguides, filters, and input couplers, are developed. First, a method of efficiently coupling THz radiation between commercial quasi-optical THz systems and integration compatible THz components is introduced. The primary method developed is the use of high-density polyethylene focusing probes which can be easily fabricated so that they are compatible with commercial THz systems. The efficiency of the probes are then investigated when used with a simple silicon-based dielectric waveguide. Next, dielectric ridge waveguides made of silicon are investigated for low loss THz wave propagation. A theoretical effective index method is applied to determine the modal propagation properties of the waveguides as well as the attenuation of the structures. FEM simulation is also carried out to verify these results. Various ridge waveguides made on silicon wafers are investigated through measurement and determined to provide low-loss waveguiding properties in the THz spectrum. The focus is then shifted to the design of thin-film integration compatible THz filters. These filters are designed with multi-objective evolutionary algorithms coupled with FEM modeling. Bandwidth, stopband characteristics, multi-resonance, and other properties of the filters are developed and improved through optimization. The filters are measured using a commercial THz system, and shown to match well with the optimized expectations.Finally, another waveguiding structure is introduced which is built with thin-metal periodic structures on thin-film substrates. These structures efficiently guide THz waves along the surface of the textured metal structures. With these structures, other passive THz circuits, such as power splitters and sensors, are also developed. The waveguiding structures, as well as power splitter, are measured in conjunction with the dielectric focusing probes developed previously, and show to provide high transmission properties at specific design frequencies. Throughout this dissertation efficient waveguides, filters, and coupling methods are introduced. These methods are compatible with current semiconductor fabrication techniques, enabling device realization directly on-wafer. In addition, all of the passive devices that are developed are simple to fabricate, as well as low-cost. Through the work presented in this dissertation, the realization of passive building blocks for on-wafer active THz circuits are developed, which in turn provides the possible realization of active on-wafer THz circuits.
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