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Articles 1 - 30 of 37
Full-Text Articles in Computer Engineering
Mass Reduction Patterning Of Silicon-On-Oxide–Based Micromirrors, Harris J. Hall, Andrew Green, Sarah Dooley, Jason D. Schmidt, Lavern A. Starman, Derrick Langley, Ronald A. Coutu Jr.
Mass Reduction Patterning Of Silicon-On-Oxide–Based Micromirrors, Harris J. Hall, Andrew Green, Sarah Dooley, Jason D. Schmidt, Lavern A. Starman, Derrick Langley, Ronald A. Coutu Jr.
Electrical and Computer Engineering Faculty Research and Publications
It has long been recognized in the design of micromirror-based optical systems that balancing static flatness of the mirror surface through structural design with the system’s mechanical dynamic response is challenging. Although a variety of mass reduction approaches have been presented in the literature to address this performance trade, there has been little quantifiable comparison reported. In this work, different mass reduction approaches, some unique to the work, are quantifiably compared with solid plate thinning in both curvature and mass using commercial finite element simulation of a specific square silicon-on-insulator–based micromirror geometry. Other important considerations for micromirror surfaces, including surface …
Investigation Of Polymer–Plasticizer Blends As Sh-Saw Sensor Coatings For Detection Of Benzene In Water With High Sensitivity And Long-Term Stability, Pintu Adhikari, Laura Jeanne Alderson, Florian Bender, Antonio J. Ricco, Fabien Josse
Investigation Of Polymer–Plasticizer Blends As Sh-Saw Sensor Coatings For Detection Of Benzene In Water With High Sensitivity And Long-Term Stability, Pintu Adhikari, Laura Jeanne Alderson, Florian Bender, Antonio J. Ricco, Fabien Josse
Electrical and Computer Engineering Faculty Research and Publications
We report the first-ever direct detection of benzene in water at concentrations below 100 ppb (parts per billion) using acoustic wave (specifically, shear-horizontal surface acoustic wave, SH-SAW) sensors with plasticized polymer coatings. Two polymers and two plasticizers were studied as materials for sensor coatings. For each polymer–plasticizer combination, the influence of the mixing ratio of the blend on the sensitivity to benzene was measured and compared to commercially available polymers that were used for BTEX (benzene, toluene, ethylbenzene, and xylene) detection in previous work. After optimizing the coating parameters, the highest sensitivity and lowest detection limit for benzene were found …
Saliency Ratio And Power Factor Of Ipm Motors Optimally Designed For High Efficiency And Low Cost Objectives, Peng Zhang, Dan M. Ionel, Nabeel Demerdash
Saliency Ratio And Power Factor Of Ipm Motors Optimally Designed For High Efficiency And Low Cost Objectives, Peng Zhang, Dan M. Ionel, Nabeel Demerdash
Electrical and Computer Engineering Faculty Research and Publications
This paper uses formal mathematical optimization techniques based on parametric finite-element-based computationally efficient models and differential evolution algorithms. For constant-power applications, in the novel approach described, three concurrent objective functions are minimized: material cost, losses, in order to ensure high efficiency, and the difference between the rated and the characteristic current, aiming to achieve very high constant-power flux-weakening range. Only the first two objectives are considered for constant-torque applications. Two types of interior permanent magnet rotors in a single- and double-layer V-shaped configuration are considered, respectively. The stator has the typical two slots per pole and phase distributed winding configuration. …
Smart Power Grid Synchronization With Fault Tolerant Nonlinear Estimation, Xin Wang, Edwin E. Yaz
Smart Power Grid Synchronization With Fault Tolerant Nonlinear Estimation, Xin Wang, Edwin E. Yaz
Electrical and Computer Engineering Faculty Research and Publications
Effective real-time state estimation is essential for smart grid synchronization, as electricity demand continues to grow, and renewable energy resources increase their penetration into the grid. In order to provide a more reliable state estimation technique to address the problem of bad data in the PMU-based power synchronization, this paper presents a novel nonlinear estimation framework to dynamically track frequency, voltage magnitudes and phase angles. Instead of directly analyzing in abc coordinate frame, symmetrical component transformation is employed to separate the positive, negative, and zero sequence networks. Then, Clarke's transformation is used to transform the sequence networks into the αβ …
A Fault-Tolerant T-Type Multilevel Inverter Topology With Soft-Switching Capability Based On Si And Sic Hybrid Phase Legs, Jiangbiao He, Nathan Weise, Ramin Katebi, Lixiang Wei, Nabeel Demerdash
A Fault-Tolerant T-Type Multilevel Inverter Topology With Soft-Switching Capability Based On Si And Sic Hybrid Phase Legs, Jiangbiao He, Nathan Weise, Ramin Katebi, Lixiang Wei, Nabeel Demerdash
Electrical and Computer Engineering Faculty Research and Publications
The performance of a novel three-phase four-leg fault-tolerant T-Type inverter topology is presented in this paper, which significantly improves the inverter's fault-tolerant capability regarding device switch faults. In this new modular inverter topology, only the redundant leg is composed of Silicon Carbide (SiC) power devices and all other phase legs are constituted by Silicon (Si) devices. The addition of the redundant leg, not only provides fault-tolerant solution to switch faults that could occur in the T-Type inverter, but also can share load current with other phase legs. Moreover, quasi zero-voltage switching (ZVS) and zero-current switching (ZCS) in the Si Insulated-Gate …
An On-Line Diagnostic Method For Open-Circuit Switch Faults In Npc Multilevel Converters, Jiangbiao He, Nabeel Demerdash
An On-Line Diagnostic Method For Open-Circuit Switch Faults In Npc Multilevel Converters, Jiangbiao He, Nabeel Demerdash
Electrical and Computer Engineering Faculty Research and Publications
On-line condition monitoring is of paramount importance for multilevel converters used in safety-critical applications. A novel on-line diagnostic method for detecting open-circuit switch faults in neutral-point-clamped (NPC) multilevel converters is introduced in this paper. The principle of this method is based on monitoring the abnormal variation of the dc-bus neutral-point current in combination with the existing information on instantaneous switching states and phase currents. Advantages of this method include simpler implementation and faster detection speed compared to other existing diagnostic methods in the literature. In this method, only one additional current sensor is required for measuring the dc-bus neutral-point current, …
Improving Gold/Gold Microcontact Performance And Reliability Under Low-Frequency Ac Through Circuit Loading, T. Laurvick, Ronald A. Coutu Jr.
Improving Gold/Gold Microcontact Performance And Reliability Under Low-Frequency Ac Through Circuit Loading, T. Laurvick, Ronald A. Coutu Jr.
Electrical and Computer Engineering Faculty Research and Publications
This paper investigates the performance and reliability of microcontacts under low-frequency and low-amplitude ac test conditions. Current microcontact theory is based on dc tests adapted to RF applications. To help better apply dc theory to RF applications, frequencies between 100 Hz to 100 kHz were experimentally investigated. Microcontacts designed to conduct performance and reliability measurements were used, which in prior dc testing typically lasted for 100 million cycles or more. Under ac loads, at similar power levels, eight devices were tested under cold-switching conditions, and only one was still operational at 10 million cycles. The effect of external circuitry on …
Thermal Management Using Mems Bimorph Cantilever Beams, Ronald A. Coutu Jr., R. S. Lafleur, J. P.K. Walton, Lavern A. Starman
Thermal Management Using Mems Bimorph Cantilever Beams, Ronald A. Coutu Jr., R. S. Lafleur, J. P.K. Walton, Lavern A. Starman
Electrical and Computer Engineering Faculty Research and Publications
This paper examines a passive cooling technique using microelectromechanical systems (MEMS) for localized thermal management of electronic devices. The prototype was designed using analytic equations, simulated using finite element methods (FEM), and fabricated using the commercial PolyMUMPs™ process. The system consisted of an electronic device simulator (EDS) and MEMS bimorph cantilever beams (MBCB) array with beams lengths of 200, 250, and 300 μm that were tested to characterize deflection and thermal behavior. The specific beam lengths were chosen to actuate in response to heating associated with the EDS (i.e. the longest beams actuated first corresponding to the hottest portion of …
Large-Scale Design Optimization Of Pm Machines Over A Target Operating Cycle, Alireza Fatemi, Nabeel Demerdash, Thomas W. Nehl, Dan M. Ionel
Large-Scale Design Optimization Of Pm Machines Over A Target Operating Cycle, Alireza Fatemi, Nabeel Demerdash, Thomas W. Nehl, Dan M. Ionel
Electrical and Computer Engineering Faculty Research and Publications
A large-scale finite element model-based design optimization algorithm is developed for improving the drive-cycle efficiency of permanent magnet (PM) synchronous machines with wide operating ranges such as those used in traction propulsion motors. The load operating cycle is efficiently modeled by using a systematic k-means clustering method to identify the operating points representing the high-energy-throughput zones in the torque-speed plane. The machine performance is evaluated over these cyclic representative points using a recently introduced computationally efficient finite element analysis, which is upgraded to include both constant torque and field-weakening operations in the evaluation of the machine performance metrics. In contrast …
Generalizing Effective Spatial Bandwidth For Pole Location In Mas: The Elliptic Cylinder, James Richie
Generalizing Effective Spatial Bandwidth For Pole Location In Mas: The Elliptic Cylinder, James Richie
Electrical and Computer Engineering Faculty Research and Publications
The location of poles in the method of auxiliary sources for 2-D scatterers can be assisted using the effective spatial bandwidth (EBW) of the incident and scattered fields. Previously, only circular boundaries were considered. Here, EBW is extended to noncircular boundaries. Calculations presented for a cylinder with elliptical cross section verify EBW as an additional tool for pole placement for more general geometries.
Mems-Based Terahertz Photoacoustic Chemical Sensing System, Nathan Glauvitz, Ronald A. Coutu Jr., Ivan R. Medvedev, Douglas T. Petkie
Mems-Based Terahertz Photoacoustic Chemical Sensing System, Nathan Glauvitz, Ronald A. Coutu Jr., Ivan R. Medvedev, Douglas T. Petkie
Electrical and Computer Engineering Faculty Research and Publications
Advancements in microelectromechanical system (MEMS) technology over the last several decades has been a driving force behind miniaturizing and improving sensor designs. In this work, a specialized cantilever pressure sensor was designed, modeled, and fabricated to investigate the photoacoustic (PA) response of gases to terahertz (THz) radiation under low-vacuum conditions associated with high-resolution spectroscopy. Microfabricated cantilever devices made using silicon-on-insulator (SOI) wafers were tested in a custom-built test chamber in this first ever demonstration of a cantilever-based PA chemical sensor and spectroscopy system in the THz frequency regime. The THz radiation source was amplitude modulated to excite acoustic waves in …
Surface Feature Engineering Through Nanosphere Lithography, Tod V. Laurvick, Ronald A. Coutu Jr., James M. Sattler, Robert A. Lake
Surface Feature Engineering Through Nanosphere Lithography, Tod V. Laurvick, Ronald A. Coutu Jr., James M. Sattler, Robert A. Lake
Electrical and Computer Engineering Faculty Research and Publications
How surface geometries can be selectively manipulated through nanosphere lithography (NSL) is discussed. Self-assembled monolayers and multilayers of nanospheres have been studied for decades and have been applied to lithography for almost as long. When compared to the most modern, state-of-the-art techniques, NSL offers comparable feature resolution with many advantages over competing technologies. Several high-resolution alternatives require scan-based implementation (i.e., focused ion beams and e-beam lithography) while NSL is much more of a batch operation, allowing for full wafer or possibly even multiple wafer processing, potentially saving time and increasing throughput in a manufacturing environment. Additionally, NSL has continued to …
Variable Response Of A Thermally Tuned Mems Pressure Sensor, Robert A. Lake, Ronald A. Coutu Jr.
Variable Response Of A Thermally Tuned Mems Pressure Sensor, Robert A. Lake, Ronald A. Coutu Jr.
Electrical and Computer Engineering Faculty Research and Publications
A typical microelectromechanical systems (MEMS) pressure sensor consists of a thin, deformable membrane and sensing element such as a piezoresistive element which is used to measure the amount of deflection in response to an applied pressure. Previous efforts demonstrated that buckled membranes, from silicon on insulator (SOI) wafers, can be thermally tuned via joule heating. By applying heat to the membrane through a resistive heating element, compressive stress is induced in the membrane causing it to buckle further out of plane and increasing its overall stiffness response. It is demonstrated that by increasing the stiffness of the membrane, the response …
Engineered Surfaces To Control Secondary Electron Emission For Multipactor Suppression, James M. Sattler, Ronald A. Coutu Jr., Robert A. Lake, Tod V. Laurvick
Engineered Surfaces To Control Secondary Electron Emission For Multipactor Suppression, James M. Sattler, Ronald A. Coutu Jr., Robert A. Lake, Tod V. Laurvick
Electrical and Computer Engineering Faculty Research and Publications
A significant problem for space-based systems is multipactor - an avalanche of electrons caused by repeated secondary electron emission (SEE). The consequences of multipactor range from altering the operation of radio frequency (RF) devices to permanent device damage. Existing efforts to suppress multipactor rely heavily on limiting power levels below a multipactor threshold [1]. This research applies surface micromachining techniques to create porous surfaces to control the secondary electron yield (SEY) of a material for multipactor suppression. Surface characteristics of interest include pore aspect ratio and density. A discussion is provided on the advantage of using electroplating (vice etching) to …
Design And Analysis Of Novel Ge-Gete Pn Junction For Photovoltaics, Andrew M. Jones, Ronald A. Coutu Jr., Robert A. Lake
Design And Analysis Of Novel Ge-Gete Pn Junction For Photovoltaics, Andrew M. Jones, Ronald A. Coutu Jr., Robert A. Lake
Electrical and Computer Engineering Faculty Research and Publications
The continuing rise in demand for energy places a similarly increasing demand to improve power production methods and efficiency. In regards to solar power generation, one major limiting factor with existing photovoltaic (PV) systems is the management of heat produced and photon interactions with the PV device. Typical devices operate within the 300-1000 nm range of the solar spectrum, greatly limiting the range of photons used for power generation. Furthermore, since infrared light (
Standardized Testing Of Non-Standard Photovoltaic Pavement Surfaces, John H. Nussbaum, Robert A. Lake, Ronald A. Coutu Jr.
Standardized Testing Of Non-Standard Photovoltaic Pavement Surfaces, John H. Nussbaum, Robert A. Lake, Ronald A. Coutu Jr.
Electrical and Computer Engineering Faculty Research and Publications
Emerging photovoltaic products have expanded the applications for the technologies into markets previously unconsidered for what was thought to be a delicate electronic product. One company leading this effort, Solar Roadways, Incorporated, is producing pavement replacing photovoltaic systems and proposing their use in everything from sidewalks to runways. Current pavement testing methods cannot be applied to these non-homogenous structures to identify if they can support the required loads. However, the standards called out specifically for pavements may be able to be translated to these products and their non-homogenous structures and non-standard materials to identify if they are able to perform …
Enhancing The Thermal Performance Of Temporary Fabric Structures For The Advanced Energy Efficient Shelter System, Justin E. Eshleman, Robert A. Lake, Ronald A. Coutu Jr.
Enhancing The Thermal Performance Of Temporary Fabric Structures For The Advanced Energy Efficient Shelter System, Justin E. Eshleman, Robert A. Lake, Ronald A. Coutu Jr.
Electrical and Computer Engineering Faculty Research and Publications
The focus of this research is to characterize the thermal load on temporary fabric shelters deployed in the Middle East in order to establish realistic contract specification for the thermal performance of future shelters. Three different testing methods were utilized to evaluate shelter thermal performance. Small-scale tests allowed for economical comparisons of different shelter materials and configurations.
Electrostrictive Polymers For Mechanical-To-Electrical Energy Harvesting, William G. Kaval, Ronald A. Coutu Jr., Robert A. Lake
Electrostrictive Polymers For Mechanical-To-Electrical Energy Harvesting, William G. Kaval, Ronald A. Coutu Jr., Robert A. Lake
Electrical and Computer Engineering Faculty Research and Publications
Research of electrostrictive polymers has generated new opportunities for harvesting energy from the surrounding environment and converting it into usable electrical energy. Piezoelectric ceramic based devices have long been used in energy harvesting for converting mechanical motion to electrical energy. Nevertheless, those materials tend to be unsuitable for low-frequency mechanical excitations such as human movement. Since organic polymers are typically softer and more flexible, the translated electrical energy output is considerably higher under the same mechanical force. Currently, investigations in using electroactive polymers for energy harvesting, and mechanical-to-electrical energy conversion, are beginning to show potential for this application. In this …
Design Of Ferroelectric Mems Energy Harvesting Devices, Noah T. Blach, Robert A. Lake, Ronald A. Coutu Jr.
Design Of Ferroelectric Mems Energy Harvesting Devices, Noah T. Blach, Robert A. Lake, Ronald A. Coutu Jr.
Electrical and Computer Engineering Faculty Research and Publications
Waste heat is a widely available but little used source of power. Converting a thermal gradient into electricity is conventionally done using the Seebeck effect, but devices that use this effect are naturally inefficient. An alternate approach uses microelectromechanical systems (MEMS) to generate movement and time-varying temperature from a constant temperature gradient. Ferroelectric materials can harvest electricity from moving structures and temperature variations. This concept was realized using traditional silicon microprocessing techniques. A silicon on insulator (SOI) wafer was backside Deep Reactive Ion Etched (DRIE) to form a one mm2 by 7 micron thick silicon/silicon dioxide membrane. Lead zirconate …
Probabilistic Anomaly Detection In Natural Gas Time Series Data, Hermine Nathalie Akouemo Kengmo Kenfack, Richard J. Povinelli
Probabilistic Anomaly Detection In Natural Gas Time Series Data, Hermine Nathalie Akouemo Kengmo Kenfack, Richard J. Povinelli
Electrical and Computer Engineering Faculty Research and Publications
This paper introduces a probabilistic approach to anomaly detection, specifically in natural gas time series data. In the natural gas field, there are various types of anomalies, each of which is induced by a range of causes and sources. The causes of a set of anomalies are examined and categorized, and a Bayesian maximum likelihood classifier learns the temporal structures of known anomalies. Given previously unseen time series data, the system detects anomalies using a linear regression model with weather inputs, after which the anomalies are tested for false positives and classified using a Bayesian classifier. The method can also …
Fast Multi-Objective Cmode-Type Optimization Of Pm Machines Using Multicore Desktop Computers, Alireza Fatemi, Dan M. Ionel, Nabeel Demerdash, Thomas W. Nehl
Fast Multi-Objective Cmode-Type Optimization Of Pm Machines Using Multicore Desktop Computers, Alireza Fatemi, Dan M. Ionel, Nabeel Demerdash, Thomas W. Nehl
Electrical and Computer Engineering Faculty Research and Publications
Large-scale design optimization of electric machines is oftentimes practiced to achieve a set of objectives, such as the minimization of cost and power loss, under a set of constraints, such as maximum permissible torque ripple. Accordingly, the design optimization of electric machines can be regarded as a constrained optimization problem (COP). Evolutionary algorithms (EAs) used in the design optimization of electric machines including differential evolution (DE), which has received considerable attention during recent years, are unconstrained optimization methods that need additional mechanisms to handle COPs. In this paper, a new optimization algorithm that features combined multi-objective optimization with differential evolution …
Cascading Failures In Interdependent Infrastructures: An Interdependent Markov-Chain Approach, Mahshid Rahnamay-Naeini, Majeed M. Hayat
Cascading Failures In Interdependent Infrastructures: An Interdependent Markov-Chain Approach, Mahshid Rahnamay-Naeini, Majeed M. Hayat
Electrical and Computer Engineering Faculty Research and Publications
Many critical infrastructures are interdependent networks in which the behavior of one network impacts those of the others. Despite the fact that interdependencies are essential for the operation of critical infrastructures, such interdependencies can negatively affect the reliability and fuel the cascade of failures within and across the networks. In this paper, a novel interdependent Markov-chain framework is proposed that enables capturing interdependencies between two critical infrastructures with the ultimate goal of predicting their resilience to cascading failures and characterizing the effects of interdependencies on system reliability. The framework is sufficiently general to model cascading failures in any interdependent networks; …
Optimal Design Of Ipm Motors With Different Cooling Systems And Winding Configurations, Alireza Fatemi, Dan M. Ionel, Nabeel Demerdash, Thomas W. Nehl
Optimal Design Of Ipm Motors With Different Cooling Systems And Winding Configurations, Alireza Fatemi, Dan M. Ionel, Nabeel Demerdash, Thomas W. Nehl
Electrical and Computer Engineering Faculty Research and Publications
Performance improvement of permanent magnet (PM) motors through optimization techniques has been widely investigated in the literature. Oftentimes the practice of design optimization leads to derivation/interpretation of optimal scaling rules of PM motors for a particular loading condition. This paper demonstrates how these derivations vary with respect to the machine ampere loading and ferrous core saturation level. A parallel sensitivity analysis using a second-order response surface methodology followed by a large-scale design optimization based on evolutionary algorithms are pursued in order to establish the variation of the relationships between the main design parameters and the performance characteristics with respect to …
Benefits Of Considering More Than Temperature Acceleration For Gan Hemt Life Testing, Ronald A. Coutu Jr., Robert A. Lake, Bradley D. Christiansen, Eric R. Heller, Christopher A. Bozada, Brian S. Poling, Glen D. Via, James P. Theimer, Stephen E. Tetlak, Ramakrishna Vetury, Jeffrey B. Shealy
Benefits Of Considering More Than Temperature Acceleration For Gan Hemt Life Testing, Ronald A. Coutu Jr., Robert A. Lake, Bradley D. Christiansen, Eric R. Heller, Christopher A. Bozada, Brian S. Poling, Glen D. Via, James P. Theimer, Stephen E. Tetlak, Ramakrishna Vetury, Jeffrey B. Shealy
Electrical and Computer Engineering Faculty Research and Publications
The purpose of this work was to investigate the validity of Arrhenius accelerated-life testing when applied to gallium nitride (GaN) high electron mobility transistors (HEMT) lifetime assessments, where the standard assumption is that only critical stressor is temperature, which is derived from operating power, device channel-case, thermal resistance, and baseplate temperature. We found that power or temperature alone could not explain difference in observed degradation, and that accelerated life tests employed by industry can benefit by considering the impact of accelerating factors besides temperature. Specifically, we found that the voltage used to reach a desired power dissipation is important, and …
Tunable Split-Ring Resonators Using Germanium Telluride, C. H. Kodama, Ronald A. Coutu Jr.
Tunable Split-Ring Resonators Using Germanium Telluride, C. H. Kodama, Ronald A. Coutu Jr.
Electrical and Computer Engineering Faculty Research and Publications
We demonstrate terahertz (THz) split-ring resonator (SRR) designs with incorporated germanium telluride (GeTe) thin films. GeTe is a chalcogenide that undergoes a nonvolatile phase change from the amorphous to crystalline state at approximately 200 degrees C, depending on the film thickness and stoichiometry. The phase change also causes a drop in the material’s resistivity by six orders of magnitude. In this study, two GeTe-incorporated SRR designs were investigated. The first was an SRR made entirely out of GeTe and the second was a gold SRR structure with a GeTe film incorporated into the gap region of the split ring. These …
Conceptual Design Of Sleeve Rotor Synchronous Reluctance Motor For Traction Applications, Patel B. Reddy, Kevin Grace, Ayman M. El-Refaie
Conceptual Design Of Sleeve Rotor Synchronous Reluctance Motor For Traction Applications, Patel B. Reddy, Kevin Grace, Ayman M. El-Refaie
Electrical and Computer Engineering Faculty Research and Publications
Synchronous reluctance machines are very appealing for high speed traction motor design due to their robustness, simple structure, absence of magnets, and simple control. The absence of magnets means that synchronous reluctance (SynRel) machines are not susceptible to price variability and sustainability of rare-earth materials. Moreover, there are no concerns about demagnetisation or uncontrolled generation mode. However, the challenge of achieving a good constant power to speed ratio is dependent on the mechanical aspects of the design. Conventional SynRel designs perform poorly compared with the permanent magnet machines due to the presence of bridges and/or centre posts in absence of …
Integrating Nanosphere Lithography In Device Fabrication, Tod V. Laurvick, Ronald A. Coutu Jr., Robert A. Lake
Integrating Nanosphere Lithography In Device Fabrication, Tod V. Laurvick, Ronald A. Coutu Jr., Robert A. Lake
Electrical and Computer Engineering Faculty Research and Publications
This paper discusses the integration of nanosphere lithography (NSL) with other fabrication techniques, allowing for nano-scaled features to be realized within larger microelectromechanical system (MEMS) based devices. Nanosphere self-patterning methods have been researched for over three decades, but typically not for use as a lithography process. Only recently has progress been made towards integrating many of the best practices from these publications and determining a process that yields large areas of coverage, with repeatability and enabled a process for precise placement of nanospheres relative to other features. Discussed are two of the more common self-patterning methods used in NSL (i.e. …
Improved Sensitivity Mems Cantilever Sensor For Terahertz Photoacoustic Spectroscopy, Ronald A. Coutu Jr., Ivan R. Medvedev, Douglas T. Petkie
Improved Sensitivity Mems Cantilever Sensor For Terahertz Photoacoustic Spectroscopy, Ronald A. Coutu Jr., Ivan R. Medvedev, Douglas T. Petkie
Electrical and Computer Engineering Faculty Research and Publications
In this paper, a microelectromechanical system (MEMS) cantilever sensor was designed, modeled and fabricated to measure the terahertz (THz) radiation induced photoacoustic (PA) response of gases under low vacuum conditions. This work vastly improves cantilever sensitivity over previous efforts, by reducing internal beam stresses, minimizing out of plane beam curvature and optimizing beam damping. In addition, fabrication yield was improved by approximately 50% by filleting the cantilever’s anchor and free end to help reduce high stress areas that occurred during device fabrication and processing. All of the cantilever sensors were fabricated using silicon-on-insulator (SOI) wafers and tested in a custom …
Robust Non-Permanent Magnet Motors For Vehicle Propulsion, Tsarajidy Raminosoa, David A. Torrey, Ayman M. El-Refaie, Di Pan, Stefan Grubic, Kevin Grace
Robust Non-Permanent Magnet Motors For Vehicle Propulsion, Tsarajidy Raminosoa, David A. Torrey, Ayman M. El-Refaie, Di Pan, Stefan Grubic, Kevin Grace
Electrical and Computer Engineering Faculty Research and Publications
There has been growing interest in electrical machines that reduce or eliminate rare-earth material content. Traction applications are among the key applications where reducing cost and hence reduction or elimination of rare-earth materials is a key requirement. This paper will assess the potential of three non-permanent magnet options in the context of vehicle propulsion applications: 1) a conventional Switched Reluctance Machine (SRM), 2) a DC-biased Reluctance Machine (DCRM) and, 3) a Wound Field Flux Switching Machine (WFFSM). The three machines were designed to achieve the hybrid vehicle traction requirements of 55kW peak and 30kW continuous over a speed range going …
Acoustic Sequences In Non-Human Animals: A Tutorial Review And Prospectus, Arik Kershenbaum, Daniel T. Blumstein, Marie A. Roch, Çağlar Akçay, Gregory Backus, Mark A. Bee, Kirsten Bohn, Yan Cao, Gerald Carter, Cristiane Cäsar, Michael Coen, Stacy L. Deruiter, Laurance Doyle, Shimon Edelman, Ramon Ferreri Cancho, Todd M. Freeberg, Ellen C. Garland, Morgan Gustison, Heidi E. Harley, Chloé Huetz, Melissa Hughes, Julia Hyland Bruno, Amiyaal Ilany, Dezhe Z. Jin, Michael T. Johnson, Chenghui Ju, Jeremy Karnowski, Bernard Lohr, Marta B. Manser, Brenda Mccowan, Eduardo Mercado Iii, Peter M. Narins, Alex Piel, Megan Rice, Roberta Salmi, Kazutoshi Sasahara, Laela Sayigh, Yu Shiu, Charles Taylor, Edgar E. Vallejo, Sara Waller, Veronica Zamora Gutierrez
Acoustic Sequences In Non-Human Animals: A Tutorial Review And Prospectus, Arik Kershenbaum, Daniel T. Blumstein, Marie A. Roch, Çağlar Akçay, Gregory Backus, Mark A. Bee, Kirsten Bohn, Yan Cao, Gerald Carter, Cristiane Cäsar, Michael Coen, Stacy L. Deruiter, Laurance Doyle, Shimon Edelman, Ramon Ferreri Cancho, Todd M. Freeberg, Ellen C. Garland, Morgan Gustison, Heidi E. Harley, Chloé Huetz, Melissa Hughes, Julia Hyland Bruno, Amiyaal Ilany, Dezhe Z. Jin, Michael T. Johnson, Chenghui Ju, Jeremy Karnowski, Bernard Lohr, Marta B. Manser, Brenda Mccowan, Eduardo Mercado Iii, Peter M. Narins, Alex Piel, Megan Rice, Roberta Salmi, Kazutoshi Sasahara, Laela Sayigh, Yu Shiu, Charles Taylor, Edgar E. Vallejo, Sara Waller, Veronica Zamora Gutierrez
Electrical and Computer Engineering Faculty Research and Publications
Animal acoustic communication often takes the form of complex sequences, made up of multiple distinct acoustic units. Apart from the well-known example of birdsong, other animals such as insects, amphibians, and mammals (including bats, rodents, primates, and cetaceans) also generate complex acoustic sequences. Occasionally, such as with birdsong, the adaptive role of these sequences seems clear (e.g. mate attraction and territorial defence). More often however, researchers have only begun to characterise – let alone understand – the significance and meaning of acoustic sequences. Hypotheses abound, but there is little agreement as to how sequences should be defined and analysed. Our …