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Ronald Coutu

Marquette University, Electrical and Computer Engineering, Faculty Member

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Ayan Roy Chaudhuri

Indian Institute of Technology Kharagpur

Arizona State University

Abdullah M. Asiri

King AbdulAziz University (KAU) Jeddah, Saudi Arabia

Dr. Prakash Chandra Mondal

Indian Institute of Technology, Kanpur

Sarah M O H A M E D el hawary

De Montfort University

Institute for Geological and Geochemical Research, Research Centre for Astronomy and Earth Sciences, Hungarian Academy of Sciences

University of Illinois at Urbana-Champaign

University of Maryland, College Park

Muhammad Zeeshan Khalid

NTNU

Manila Chieruzzi

University of Perugia, Italy

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Papers by Ronald Coutu

Thin Film Materials for Room Temperature Quantum Applications

IEEE Transactions on Quantum Engineering

Thin films with quantum defects are emerging as a potential platform for quantum applications. Qu... more Thin films with quantum defects are emerging as a potential platform for quantum applications. Quantum defects in some thin films arise due to structural imperfections, such as vacancies or impurities. These defects generate localized electronic states with unique optical and electronic properties. Crystal vacancies or defects that occur when atoms are missing from a crystal lattice can influence a material's quantum properties. In this study, we investigated inexpensive, complementary metal oxide semiconductor compatible materials with quantum defects suitable for room temperature applications. The experiments indicated 5, 15, and 17 ns relaxation times for aluminum nitride, aluminum oxide or alumina, and tin oxides, respectively. For all these materials, distinct resonant peaks are observed at approximately 1.1, 1.6, 2.2, and 2.7 GHz at room temperature (i.e., 21°C). These peaks exhibit slight frequency shifts, corresponding to known defect locations and thin film material properties. This discovery may lead the way to reliable, cost-effective quantum applications in our daily lives. INDEX TERMS Bandgap, microelectromechanical systems (MEMS), quantum information system (QIS), thin film, vacancy defect.

Designing, fabricating and testing multi-junction silicon solar cells

Photovoltaic research and technology have grown exponentially in recent years due to the continui... more Photovoltaic research and technology have grown exponentially in recent years due to the continuing and increasing global demand for energy. However, to be economical for global production and utilization, the efficiency of solar cells must increase without escalating manufacturing costs. Because of the abundance of silicon and vast knowledge obtained from silicon study, exhaustive exploitation of silicon-based solar cell design is vital to meet both criteria. Positive thermal control and improved photon recycling are two methods to increase solar cell efficiency. A recently developed hybrid multi-junction silicon (HMJ-Si) solar cell architecture was designed to positively manage these two factors, as well as the common resulting photonic interference pattern generated from the electrical contact gratings. Because of the integrated air gap between two stacked silicon substrates, this sandwiched-cavity imparted a 1.70C differential temperature. The top and bottom substrates were electrically connected in parallel via a copper o-ring with a thickness of 385μm which was the optimal, calculated air gap distance for photon propagation wavelengths of 800nm-1100nm. The HMJ-Si solar cell was tested using a solar simulator with an air mass 1.5 full spectrum sunlight output and a class II pyranometer with a spectral response of 310nm-2800nm. The HMJ-Si solar cell demonstrated photovoltaic efficiency of 8-10%.

PVDF-TrFE Electroactive Polymer Based Micro-Electro-Mechanical Systems (MEMs) Structures

Conference proceedings of the Society for Experimental Mechanics, Oct 18, 2017

Electroactive polymer (EAP) has recently been receiving significant attention as smart materials ... more Electroactive polymer (EAP) has recently been receiving significant attention as smart materials for actuators and sensors for novel micro fabricated devices. Polymer film devices have demonstrated use as pressure sensors and shown potential for harvesting energy from the natural environment. Fabrication of sensing devices using copolymer films has been accomplished using standard lithography process. Materials such as P(VDF-TrFE) (polyvinyledenedifluoride-tetrafluoroethylene) copolymer films (1 m thick or less) were evaluated and presented a large relative permittivity and greater piezoelectric-phase without stretching. Mechanical analysis of experimental structures was also provided and led to key design rules for key post-processing steps to control the performance of the devices. Further investigations will be used to identify suitable micro-electro-mechanical systems (MEMs) structures.

Mass reduction patterning of silicon-on-oxide–based micromirrors

Journal of Micro-nanolithography Mems and Moems, Dec 20, 2016

It has long been recognized in the design of micromirror-based optical systems that balancing sta... more 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 profile and smoothness, are also discussed. Fabrication of one of these geometries, a two-dimensional tessellated square pattern, was performed in the presence of a 400-μm-tall central post structure using a simple single mask process. Limited experimental curvature measurements of fabricated samples are shown to correspond well with properly characterized simulation results and indicate ∼67% improvement in radius of curvature in comparison to a solid plate design of equivalent mass.

Germanium Telluride (GeTe) phase change resistors for reconfigurable circuit applications

In this paper, we report on the electrical properties of the phase change (PC) material, Germaniu... more In this paper, we report on the electrical properties of the phase change (PC) material, Germanium Telluride (GeTe), and discuss the fabrication and testing of GeTe resistors. Vertical and horizontal GeTe resistors are fabricated and tested through resistance measurements before and after substrate heating and joule heating performed by voltage pulsing. Resistance changes of six orders of magnitude and four orders of magnitude are demonstrated by substrate heating and voltage pulsing, respectively. The horizontal resistor designs are shown to be impractical for low voltage applications due to the their large inter-electrode distances. Various sizes of GeTe resistors ranging from 15×15×0.4 μm3 to 3×3×0.09 μm3 are tested and a relationship is demonstrated between GeTe resistor length and the threshold voltage pulse required for phase change.

Micro-contact performance and reliability under low frequency, low amplitude, alternating current (AC) test conditions

This paper presents an experimental investigation of micro-contact performance (i.e. contact resi... more This paper presents an experimental investigation of micro-contact performance (i.e. contact resistance) and reliability (i.e. successful cycles) evaluated under time-varying, low frequency, low amplitude, alternating current (AC) test conditions. Previous research efforts have focused on either on direct current (DC) or high frequency, radio frequency (RF) test conditions. This works attempts to bridge the gap in prior work by generating knowledge related to frequency, phase, and amplitude effects on micron-sized electrical contacts. Contact support structures, micromachined with gold on gold micro-contacts, were actuated using an externally applied contact load of approximately 200 µN and tested in dry, nitrogen ambient environments to minimize pre-test contact surface contamination. Contact resistances measured were comparable to those obtained using a DC. However, reliability is drastically reduced with AC signals between 100 to 100 kHz. Device failure typically occurred prior to 10k cycles on devices proven to last beyond 100M cycles or more under DC conditions. Phase of the AC appeared to have some influence on the manner of failure, as did AC signals that persisted through contact opening. In all cases examined, noticeable physical damage in the form of material migration was observed using a scanning electron microscope.

Reliability Evolution of Au-Au, Au-Ru and Au-RuO2 Micro-Contacts

This paper presents a comparison between microcontact pairs of Au-Au, Au-Ru and Au-RuO2. The cont... more This paper presents a comparison between microcontact pairs of Au-Au, Au-Ru and Au-RuO2. The contact pairs were made with an evaporated Au lower planar contact and sputtered Au, Ru or RuO2 upper hemispherical contact. The RuO2 was reactively sputtered in both a 10% and 25% O2:Ar environment. The evolution of the contact area was observed by actuating the micro-contact to 1, 10(exp 2), 10(exp 3), 5 x 10(exp 3), 10(exp 4), 5 x 10(exp 4), 10(exp 5), 5 x 10(exp 5), 10(exp 6), 5 x 10(exp 6) and 10(exp 7) cycles. The micro-contacts were actuated using an external, calibrated point load. To examine the micro-contact performance, the contact resistance and force required to close the contact were monitored simultaneously throughout testing. At the above stated end point, the microcontact was folded back to evaluate the wear of the upper hemispherical and planar lower contact. The contacts were also examined with an scanning electron microscope to investigate the contact surfaces. This paper will present the contact evolution between contact pairs of Au-Au, Au-Ru and Au-RuO2 microcontacts between 1 and 10(exp 7) cycles. It was found that the contact resistance for the Au/Ru was 1.7 Omega, Au/RuO2 10% was 1.36 Omega, Au/RuO2 25% was 0.036 Omega.

Testing Photovoltaic Pavers for Roadway Applications

Sustainability in environment, Apr 2, 2019

Concrete and asphalt are the primary materials used to construct roadways for motor vehicles, bik... more Concrete and asphalt are the primary materials used to construct roadways for motor vehicles, bike paths for pedestrians and bicyclists, and runways for aircraft. Solar Roadways®, Inc. (SR) in Sandpoint, ID, proposed using robust, Solar Road Panels (SRPs) as an alternative roadway material due to the potential for creating a modular, multi-functional infrastructure product with cost-savings, user-safety, power-generation, and a better alternative in terms o f environmental sustainability when compared to contemporary pavement materials. Typical roadway construction materials, on average, need to be replaced every 10-15 years while also requiring regular annual maintenance to maintain proper safety standards. SR's novel roadway material is intended to extend roadway replacement timelines, lower annual maintenance costs, and provide energy to the power grid. In this study, we tested the mechanical properties of the "SR3" model prototype SRP and evaluated its suitability as a replacement roadway material with the added benefit of generating electric power. Specifically, we tested this unique pavement material in submerged water environments, under extreme temperature conditions, and under dynamic loading conditions.

Serviceability Optimization of the Next Generation Wind Turbines Using Internet of Things Platform

2018 Smart Grid Conference (SGC)

Internet of Things, Big data, connected technologies, and advanced materials are spearheading the... more Internet of Things, Big data, connected technologies, and advanced materials are spearheading the growth of an increasingly competitive wind power sector. Wind power market has seen “tremendous growth” in recent years, and will reach even greater heights as IoT technology advances. The primary hot researches in this field focus on wind farm producibility, safety and reliability, and financial risk management. Therefore, essential questions in a topical farm are as follows: How long wind turbines can work efficiently? When is the best time for maintenance? Which measures can be used for essential monitoring of the system? How reliable are the selected measurements to guarantee the safety and predictability of the wind farm? To address the above concerns and design a reliable framework for health monitoring of wind turbines, critical components in wind turbines such as gearboxes, blade, power converter, and others parts are investigated using a recommended IoT platform. The priory goal is to develop IoT system to monitor wind turbine using available measurements through IoT's sensors. Then, potential faults are identified by a diagnosis unit using data mining approaches.

Microcontact Support Structure Fabrication to Study Microswitches Reliability and Performance Using a Novel Test Fixture

2022 IEEE 67th Holm Conference on Electrical Contacts (HLM)

Investigating the dynamic response of heterogeneous mixtures with variable geometric complexity

Critical Experiments Leading to a Novel Test Fixture Assembly for Microcontact Reliability and Performance Research

2019 IEEE Holm Conference on Electrical Contacts, 2019

In microelectromechanical systems (MEMS) ohmic contact switches, reliability is of great concern ... more In microelectromechanical systems (MEMS) ohmic contact switches, reliability is of great concern where billions of cycle operation is a requirement. Microcontact surface tribology plays the critical role in determining their reliability and performance. In this work, a novel, simple, quick and efficient test fixture has been designed and assembled to study the contact resistance, contact force, adhesion force, and contamination associated with the microcontact. In support of developing the test fixture, we evaluated the performance limitations of each components (i.e. piezoelectric actuators, force sensors, nanomax stage) independently. Force versus position, force versus voltage, and position versus voltage data have been collected for each test fixture components under direct current (DC) condition. A customized stage fixture has been 3D printed for holding the microcontact support structure. We use Thorlab’s state-of-the-art nanomax stage to provide nanometric positioning and precise alignment between the microcontact area and the force sensor on three orthogonal axes. We fabricate a novel contact support structure to test the feasibility of our test fixture and collect force and resistance data simultaneously at the rate of $\sim$5 KHz using LabView. Data obtained from the test fixture will provide significant information to design a robust and reliable MEMS switch for future DC and RF applications.

Metal-insulator transition (MIT) actuators for microswitching applications

International Workshop on Thin Films for Electronics, Electro-Optics, Energy, and Sensors 2019, 2019

Transitional metal oxides have generated considerable interest in electronics and other engineeri... more Transitional metal oxides have generated considerable interest in electronics and other engineering applications over the last few decades. These materials show several orders of magnitude metal-insulator transition (MIT) when triggered by an external stimuli. In this paper, an MIT (Vanadium Dioxide (VO2)) -based bimorph cantilever shows promising performance due to its large volumetric work density, ultrafast response, and reliability. This this work, we propose and simulate a cantilever actuated via VO2 for a micro-contact switch. Our results show VO2 based actuators show promising performance in terms of deflection, resonance frequency, and lifetime.

Determining the non-ideal parallel-plate capacitance of a split-ring resonator gap

2015 9th International Congress on Advanced Electromagnetic Materials in Microwaves and Optics (METAMATERIALS), 2015

Metamaterials in the terahertz range or higher typically have gaps that are far from an ideal par... more Metamaterials in the terahertz range or higher typically have gaps that are far from an ideal parallel plate due to microfabrication limitations on feature size. This work examines the exact solution to the square parallel plate capacitor and finds a valid approximation for capacitance in non-ideal geometries, when the gap size is comparable or larger than the dimensions of the plates.

Metal-insulator transition (MIT) materials for biomedical applications

International Journal of Biosensors & Bioelectronics, 2019

Transitional metal oxides get considerable interest in electronics and other engineering applicat... more Transitional metal oxides get considerable interest in electronics and other engineering applications over few decades. These materials show several orders of magnitude metalinsulator transition (MIT) triggered by external stimuli. Bio-sensing using Vanadium dioxide (VO 2 ), a MIT material is largely unexplored. In this short article, we investigate the VO 2 based thermal sensor performance for measuring the biomolecule concentration. Active sensing layer is chromium and niobium co-doped VO 2 as it shows 11.9%/°C temperature coefficient of resistance (TCR) with practically no thermal hysteresis . Our study demonstrated that VO 2 based microsensors can be used to measure the biomolecule concentrations, which produce temperature changes in the mK range. For 1mK change in temperature, the maximum detection voltage is near 0.4V.

Engineered surfaces to control secondary electron emission for multipactor suppression

2016 IEEE National Aerospace and Electronics Conference (NAECON) and Ohio Innovation Summit (OIS), 2016

A significant problem for space-based systems is multipactor-an avalanche of electrons caused by ... more 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 create porous surfaces for studying the relationships between SEY and pore aspect ratio & density (i.e. porosity). Preventing multipactor through SEY reduction will allow power level restrictions to be eased, leading to more powerful and capable space-based systems.

Design of FerroElectric MEMS energy harvesting devices

2016 IEEE National Aerospace and Electronics Conference (NAECON) and Ohio Innovation Summit (OIS), 2016

Mechanical logic using MEMS

2015 National Aerospace and Electronics Conference (NAECON), 2015

ABSTRACT

Fabrication of microelectromechanical systems (MEMS) cantilevers for photoacoustic (PA) detection of terahertz (THz) radiation

SPIE Proceedings, 2014

This paper is NOT THE PUBLISHED VERSION; but the author's final, peer-reviewed manuscript. The pu... more

Bending induced tuning of the resonant response of a flexible THz metamaterial device

2014 39th International Conference on Infrared, Millimeter, and Terahertz waves (IRMMW-THz), 2014

The effects of bending a 2-dimensional planar array of rectangular split-ring resonators (SRRs) i... more The effects of bending a 2-dimensional planar array of rectangular split-ring resonators (SRRs) is observed by mounting the array to varying diameter HDPE cylinders. By studying the transmission of pulsed THz light through the SRR-cylinder system, it shown that the resonant frequency and response of the arrays are tunable as a function of the radius of curvature.

Thin Film Materials for Room Temperature Quantum Applications

IEEE Transactions on Quantum Engineering

Thin films with quantum defects are emerging as a potential platform for quantum applications. Qu... more Thin films with quantum defects are emerging as a potential platform for quantum applications. Quantum defects in some thin films arise due to structural imperfections, such as vacancies or impurities. These defects generate localized electronic states with unique optical and electronic properties. Crystal vacancies or defects that occur when atoms are missing from a crystal lattice can influence a material's quantum properties. In this study, we investigated inexpensive, complementary metal oxide semiconductor compatible materials with quantum defects suitable for room temperature applications. The experiments indicated 5, 15, and 17 ns relaxation times for aluminum nitride, aluminum oxide or alumina, and tin oxides, respectively. For all these materials, distinct resonant peaks are observed at approximately 1.1, 1.6, 2.2, and 2.7 GHz at room temperature (i.e., 21°C). These peaks exhibit slight frequency shifts, corresponding to known defect locations and thin film material properties. This discovery may lead the way to reliable, cost-effective quantum applications in our daily lives. INDEX TERMS Bandgap, microelectromechanical systems (MEMS), quantum information system (QIS), thin film, vacancy defect.

Designing, fabricating and testing multi-junction silicon solar cells

Photovoltaic research and technology have grown exponentially in recent years due to the continui... more Photovoltaic research and technology have grown exponentially in recent years due to the continuing and increasing global demand for energy. However, to be economical for global production and utilization, the efficiency of solar cells must increase without escalating manufacturing costs. Because of the abundance of silicon and vast knowledge obtained from silicon study, exhaustive exploitation of silicon-based solar cell design is vital to meet both criteria. Positive thermal control and improved photon recycling are two methods to increase solar cell efficiency. A recently developed hybrid multi-junction silicon (HMJ-Si) solar cell architecture was designed to positively manage these two factors, as well as the common resulting photonic interference pattern generated from the electrical contact gratings. Because of the integrated air gap between two stacked silicon substrates, this sandwiched-cavity imparted a 1.70C differential temperature. The top and bottom substrates were electrically connected in parallel via a copper o-ring with a thickness of 385μm which was the optimal, calculated air gap distance for photon propagation wavelengths of 800nm-1100nm. The HMJ-Si solar cell was tested using a solar simulator with an air mass 1.5 full spectrum sunlight output and a class II pyranometer with a spectral response of 310nm-2800nm. The HMJ-Si solar cell demonstrated photovoltaic efficiency of 8-10%.

PVDF-TrFE Electroactive Polymer Based Micro-Electro-Mechanical Systems (MEMs) Structures

Conference proceedings of the Society for Experimental Mechanics, Oct 18, 2017

Electroactive polymer (EAP) has recently been receiving significant attention as smart materials ... more Electroactive polymer (EAP) has recently been receiving significant attention as smart materials for actuators and sensors for novel micro fabricated devices. Polymer film devices have demonstrated use as pressure sensors and shown potential for harvesting energy from the natural environment. Fabrication of sensing devices using copolymer films has been accomplished using standard lithography process. Materials such as P(VDF-TrFE) (polyvinyledenedifluoride-tetrafluoroethylene) copolymer films (1 m thick or less) were evaluated and presented a large relative permittivity and greater piezoelectric-phase without stretching. Mechanical analysis of experimental structures was also provided and led to key design rules for key post-processing steps to control the performance of the devices. Further investigations will be used to identify suitable micro-electro-mechanical systems (MEMs) structures.

Mass reduction patterning of silicon-on-oxide–based micromirrors

Journal of Micro-nanolithography Mems and Moems, Dec 20, 2016

It has long been recognized in the design of micromirror-based optical systems that balancing sta... more 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 profile and smoothness, are also discussed. Fabrication of one of these geometries, a two-dimensional tessellated square pattern, was performed in the presence of a 400-μm-tall central post structure using a simple single mask process. Limited experimental curvature measurements of fabricated samples are shown to correspond well with properly characterized simulation results and indicate ∼67% improvement in radius of curvature in comparison to a solid plate design of equivalent mass.

Germanium Telluride (GeTe) phase change resistors for reconfigurable circuit applications

In this paper, we report on the electrical properties of the phase change (PC) material, Germaniu... more In this paper, we report on the electrical properties of the phase change (PC) material, Germanium Telluride (GeTe), and discuss the fabrication and testing of GeTe resistors. Vertical and horizontal GeTe resistors are fabricated and tested through resistance measurements before and after substrate heating and joule heating performed by voltage pulsing. Resistance changes of six orders of magnitude and four orders of magnitude are demonstrated by substrate heating and voltage pulsing, respectively. The horizontal resistor designs are shown to be impractical for low voltage applications due to the their large inter-electrode distances. Various sizes of GeTe resistors ranging from 15×15×0.4 μm3 to 3×3×0.09 μm3 are tested and a relationship is demonstrated between GeTe resistor length and the threshold voltage pulse required for phase change.

Micro-contact performance and reliability under low frequency, low amplitude, alternating current (AC) test conditions

This paper presents an experimental investigation of micro-contact performance (i.e. contact resi... more This paper presents an experimental investigation of micro-contact performance (i.e. contact resistance) and reliability (i.e. successful cycles) evaluated under time-varying, low frequency, low amplitude, alternating current (AC) test conditions. Previous research efforts have focused on either on direct current (DC) or high frequency, radio frequency (RF) test conditions. This works attempts to bridge the gap in prior work by generating knowledge related to frequency, phase, and amplitude effects on micron-sized electrical contacts. Contact support structures, micromachined with gold on gold micro-contacts, were actuated using an externally applied contact load of approximately 200 µN and tested in dry, nitrogen ambient environments to minimize pre-test contact surface contamination. Contact resistances measured were comparable to those obtained using a DC. However, reliability is drastically reduced with AC signals between 100 to 100 kHz. Device failure typically occurred prior to 10k cycles on devices proven to last beyond 100M cycles or more under DC conditions. Phase of the AC appeared to have some influence on the manner of failure, as did AC signals that persisted through contact opening. In all cases examined, noticeable physical damage in the form of material migration was observed using a scanning electron microscope.

Reliability Evolution of Au-Au, Au-Ru and Au-RuO2 Micro-Contacts

This paper presents a comparison between microcontact pairs of Au-Au, Au-Ru and Au-RuO2. The cont... more This paper presents a comparison between microcontact pairs of Au-Au, Au-Ru and Au-RuO2. The contact pairs were made with an evaporated Au lower planar contact and sputtered Au, Ru or RuO2 upper hemispherical contact. The RuO2 was reactively sputtered in both a 10% and 25% O2:Ar environment. The evolution of the contact area was observed by actuating the micro-contact to 1, 10(exp 2), 10(exp 3), 5 x 10(exp 3), 10(exp 4), 5 x 10(exp 4), 10(exp 5), 5 x 10(exp 5), 10(exp 6), 5 x 10(exp 6) and 10(exp 7) cycles. The micro-contacts were actuated using an external, calibrated point load. To examine the micro-contact performance, the contact resistance and force required to close the contact were monitored simultaneously throughout testing. At the above stated end point, the microcontact was folded back to evaluate the wear of the upper hemispherical and planar lower contact. The contacts were also examined with an scanning electron microscope to investigate the contact surfaces. This paper will present the contact evolution between contact pairs of Au-Au, Au-Ru and Au-RuO2 microcontacts between 1 and 10(exp 7) cycles. It was found that the contact resistance for the Au/Ru was 1.7 Omega, Au/RuO2 10% was 1.36 Omega, Au/RuO2 25% was 0.036 Omega.

Testing Photovoltaic Pavers for Roadway Applications

Sustainability in environment, Apr 2, 2019

Concrete and asphalt are the primary materials used to construct roadways for motor vehicles, bik... more Concrete and asphalt are the primary materials used to construct roadways for motor vehicles, bike paths for pedestrians and bicyclists, and runways for aircraft. Solar Roadways®, Inc. (SR) in Sandpoint, ID, proposed using robust, Solar Road Panels (SRPs) as an alternative roadway material due to the potential for creating a modular, multi-functional infrastructure product with cost-savings, user-safety, power-generation, and a better alternative in terms o f environmental sustainability when compared to contemporary pavement materials. Typical roadway construction materials, on average, need to be replaced every 10-15 years while also requiring regular annual maintenance to maintain proper safety standards. SR's novel roadway material is intended to extend roadway replacement timelines, lower annual maintenance costs, and provide energy to the power grid. In this study, we tested the mechanical properties of the "SR3" model prototype SRP and evaluated its suitability as a replacement roadway material with the added benefit of generating electric power. Specifically, we tested this unique pavement material in submerged water environments, under extreme temperature conditions, and under dynamic loading conditions.

Serviceability Optimization of the Next Generation Wind Turbines Using Internet of Things Platform

2018 Smart Grid Conference (SGC)

Internet of Things, Big data, connected technologies, and advanced materials are spearheading the... more Internet of Things, Big data, connected technologies, and advanced materials are spearheading the growth of an increasingly competitive wind power sector. Wind power market has seen “tremendous growth” in recent years, and will reach even greater heights as IoT technology advances. The primary hot researches in this field focus on wind farm producibility, safety and reliability, and financial risk management. Therefore, essential questions in a topical farm are as follows: How long wind turbines can work efficiently? When is the best time for maintenance? Which measures can be used for essential monitoring of the system? How reliable are the selected measurements to guarantee the safety and predictability of the wind farm? To address the above concerns and design a reliable framework for health monitoring of wind turbines, critical components in wind turbines such as gearboxes, blade, power converter, and others parts are investigated using a recommended IoT platform. The priory goal is to develop IoT system to monitor wind turbine using available measurements through IoT's sensors. Then, potential faults are identified by a diagnosis unit using data mining approaches.

Microcontact Support Structure Fabrication to Study Microswitches Reliability and Performance Using a Novel Test Fixture

2022 IEEE 67th Holm Conference on Electrical Contacts (HLM)

Investigating the dynamic response of heterogeneous mixtures with variable geometric complexity

Critical Experiments Leading to a Novel Test Fixture Assembly for Microcontact Reliability and Performance Research

2019 IEEE Holm Conference on Electrical Contacts, 2019

In microelectromechanical systems (MEMS) ohmic contact switches, reliability is of great concern ... more In microelectromechanical systems (MEMS) ohmic contact switches, reliability is of great concern where billions of cycle operation is a requirement. Microcontact surface tribology plays the critical role in determining their reliability and performance. In this work, a novel, simple, quick and efficient test fixture has been designed and assembled to study the contact resistance, contact force, adhesion force, and contamination associated with the microcontact. In support of developing the test fixture, we evaluated the performance limitations of each components (i.e. piezoelectric actuators, force sensors, nanomax stage) independently. Force versus position, force versus voltage, and position versus voltage data have been collected for each test fixture components under direct current (DC) condition. A customized stage fixture has been 3D printed for holding the microcontact support structure. We use Thorlab’s state-of-the-art nanomax stage to provide nanometric positioning and precise alignment between the microcontact area and the force sensor on three orthogonal axes. We fabricate a novel contact support structure to test the feasibility of our test fixture and collect force and resistance data simultaneously at the rate of $\sim$5 KHz using LabView. Data obtained from the test fixture will provide significant information to design a robust and reliable MEMS switch for future DC and RF applications.

Metal-insulator transition (MIT) actuators for microswitching applications

International Workshop on Thin Films for Electronics, Electro-Optics, Energy, and Sensors 2019, 2019

Transitional metal oxides have generated considerable interest in electronics and other engineeri... more Transitional metal oxides have generated considerable interest in electronics and other engineering applications over the last few decades. These materials show several orders of magnitude metal-insulator transition (MIT) when triggered by an external stimuli. In this paper, an MIT (Vanadium Dioxide (VO2)) -based bimorph cantilever shows promising performance due to its large volumetric work density, ultrafast response, and reliability. This this work, we propose and simulate a cantilever actuated via VO2 for a micro-contact switch. Our results show VO2 based actuators show promising performance in terms of deflection, resonance frequency, and lifetime.

Determining the non-ideal parallel-plate capacitance of a split-ring resonator gap

2015 9th International Congress on Advanced Electromagnetic Materials in Microwaves and Optics (METAMATERIALS), 2015

Metamaterials in the terahertz range or higher typically have gaps that are far from an ideal par... more Metamaterials in the terahertz range or higher typically have gaps that are far from an ideal parallel plate due to microfabrication limitations on feature size. This work examines the exact solution to the square parallel plate capacitor and finds a valid approximation for capacitance in non-ideal geometries, when the gap size is comparable or larger than the dimensions of the plates.

Metal-insulator transition (MIT) materials for biomedical applications

International Journal of Biosensors & Bioelectronics, 2019

Transitional metal oxides get considerable interest in electronics and other engineering applicat... more Transitional metal oxides get considerable interest in electronics and other engineering applications over few decades. These materials show several orders of magnitude metalinsulator transition (MIT) triggered by external stimuli. Bio-sensing using Vanadium dioxide (VO 2 ), a MIT material is largely unexplored. In this short article, we investigate the VO 2 based thermal sensor performance for measuring the biomolecule concentration. Active sensing layer is chromium and niobium co-doped VO 2 as it shows 11.9%/°C temperature coefficient of resistance (TCR) with practically no thermal hysteresis . Our study demonstrated that VO 2 based microsensors can be used to measure the biomolecule concentrations, which produce temperature changes in the mK range. For 1mK change in temperature, the maximum detection voltage is near 0.4V.

Engineered surfaces to control secondary electron emission for multipactor suppression

2016 IEEE National Aerospace and Electronics Conference (NAECON) and Ohio Innovation Summit (OIS), 2016

A significant problem for space-based systems is multipactor-an avalanche of electrons caused by ... more 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 create porous surfaces for studying the relationships between SEY and pore aspect ratio & density (i.e. porosity). Preventing multipactor through SEY reduction will allow power level restrictions to be eased, leading to more powerful and capable space-based systems.

Design of FerroElectric MEMS energy harvesting devices

2016 IEEE National Aerospace and Electronics Conference (NAECON) and Ohio Innovation Summit (OIS), 2016

Mechanical logic using MEMS

2015 National Aerospace and Electronics Conference (NAECON), 2015

ABSTRACT

Fabrication of microelectromechanical systems (MEMS) cantilevers for photoacoustic (PA) detection of terahertz (THz) radiation

SPIE Proceedings, 2014

This paper is NOT THE PUBLISHED VERSION; but the author's final, peer-reviewed manuscript. The pu... more

Bending induced tuning of the resonant response of a flexible THz metamaterial device

2014 39th International Conference on Infrared, Millimeter, and Terahertz waves (IRMMW-THz), 2014

The effects of bending a 2-dimensional planar array of rectangular split-ring resonators (SRRs) i... more The effects of bending a 2-dimensional planar array of rectangular split-ring resonators (SRRs) is observed by mounting the array to varying diameter HDPE cylinders. By studying the transmission of pulsed THz light through the SRR-cylinder system, it shown that the resonant frequency and response of the arrays are tunable as a function of the radius of curvature.