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Exchanging Ohmic Losses In Metamaterial Absorbers With Useful Optical Absorption For Photovoltaics, Ankit Vora, Jephias Gwamuri, Nezih Pala, Anand Kulkarni, Joshua M. Pearce, Durdu Ö. Güney 2017 Michigan Technological University

Exchanging Ohmic Losses In Metamaterial Absorbers With Useful Optical Absorption For Photovoltaics, Ankit Vora, Jephias Gwamuri, Nezih Pala, Anand Kulkarni, Joshua M. Pearce, Durdu Ö. Güney

Joshua M. Pearce

Using metamaterial absorbers, we have shown that metallic layers in the absorbers do not necessarily constitute undesired resistive heating problem for photovoltaics. Tailoring the geometric skin depth of metals and employing the natural bulk absorbance characteristics of the semiconductors in those absorbers can enable the exchange of undesired resistive losses with the useful optical absorbance in the active semiconductors. Thus, Ohmic loss dominated metamaterial absorbers can be converted into photovoltaic near-perfect absorbers with the advantage of harvesting the full potential of light management offered by the metamaterial absorbers. Based on experimental permittivity data for indium gallium nitride, we have shown ...


Influence Of Oxygen Concentration On The Performance Of Ultra-Thin Rf Magnetron Sputter Deposited Indium Tin Oxide Films As A Top Electrode For Photovoltaic Devices, Jephias Gwamuri, Murugesan Marikkannan, J. Mayandi, Patrick Bowen, Joshua M. Pearce 2017 Michigan Technological University

Influence Of Oxygen Concentration On The Performance Of Ultra-Thin Rf Magnetron Sputter Deposited Indium Tin Oxide Films As A Top Electrode For Photovoltaic Devices, Jephias Gwamuri, Murugesan Marikkannan, J. Mayandi, Patrick Bowen, Joshua M. Pearce

Joshua M. Pearce

The opportunity for substantial efficiency enhancements of thin film hydrogenated amorphous silicon (a-Si:H) solar photovoltaic (PV) cells using plasmonic absorbers requires ultra-thin transparent conducting oxide top electrodes with low resistivity and high transmittances in the visible range of the electromagnetic spectrum. Fabricating ultra-thin indium tin oxide (ITO) films (sub-50 nm) using conventional methods has presented a number of challenges; however, a novel method involving chemical shaving of thicker (greater than 80 nm) RF sputter deposited high-quality ITO films has been demonstrated. This study investigates the effect of oxygen concentration on the etch rates of RF sputter deposited ITO films ...


Controlling Optical Absorption In Metamaterial Absorbers For Plasmonic Solar Cells, Wyatt Adams, Ankit Vora, Jephias Gwamuri, Joshua M. Pearce, Durdo O. Guney 2017 Michigan Technological University

Controlling Optical Absorption In Metamaterial Absorbers For Plasmonic Solar Cells, Wyatt Adams, Ankit Vora, Jephias Gwamuri, Joshua M. Pearce, Durdo O. Guney

Joshua M. Pearce

Metals in the plasmonic metamaterial absorbers for photovoltaics constitute undesired resistive heating. However, tailoring the geometric skin depth of metals can minimize resistive losses while maximizing the optical absorbance in the active semiconductors of the photovoltaic device. Considering experimental permittivity data for InxGa1-xN, absorbance in the semiconductor layers of the photovoltaic device can reach above 90%. The results here also provides guidance to compare the performance of different semiconductor materials. This skin depth engineering approach can also be applied to other optoelectronic devices, where optimizing the device performance demands minimizing resistive losses and power consumption, such as photodetectors, laser diodes ...


Heuristics From Statistics—Modeling The Behavior And Perception Of Non-Rigid Materials, Vivian C. Paulun, Roland W. Fleming 2017 Justus Liebig University, Giessen

Heuristics From Statistics—Modeling The Behavior And Perception Of Non-Rigid Materials, Vivian C. Paulun, Roland W. Fleming

MODVIS Workshop

No abstract provided.


Modelling Grip Point Selection In Human Precision Grip, Guido Maiello, Lina Klein, Vivian C. Paulun, Roland W. Fleming 2017 University of Gießen

Modelling Grip Point Selection In Human Precision Grip, Guido Maiello, Lina Klein, Vivian C. Paulun, Roland W. Fleming

MODVIS Workshop

No abstract provided.


Flexible Plasmonic Sensing Substrates And Their Application In Explosive Sensing, Justin Bae, Srikanth Singamaneni 2017 Washington University in St Louis

Flexible Plasmonic Sensing Substrates And Their Application In Explosive Sensing, Justin Bae, Srikanth Singamaneni

Engineering and Applied Science Theses & Dissertations

With an increasing use of improvised explosive devices in combat and terrorism, there is an urgent need for novel methods of trace explosive detection that can provide an inexpensive and effective solution. This study focuses on the development of such platform using flexible surface enhanced Raman scattering (SERS) substrates. Gold nanorods(AuNR) functionalized with peptides selective to explosive molecules, trinitrotoluene(TNT) and dinitrotoluene (DNT) were immobilized on various substrates to fabricate a flexible SERS substrate. The peptide conjugated AuNRs can detect TNT and DNT vapors, and the cysteamine conjugated nanorods could detect TNT in aqueous solution down to 100 nM ...


Cache Power Optimization Using Multiple Voltage Supplies To Exploit Read/Write Asymmetry, Dengxue Yan 2017 Washington University in St. Louis

Cache Power Optimization Using Multiple Voltage Supplies To Exploit Read/Write Asymmetry, Dengxue Yan

Engineering and Applied Science Theses & Dissertations

Power consumption becomes more and more critical in computer systems nowadays. Most of the previous work has been focusing on general-purpose computational core, but optimization techniques for conventional CPU core has reached a limit. Our experimental results show that read operations in SRAM can be performed at a lower supply with much reduced power consumption compared to write operations. Based on this observation and the fact that cache, consisting mostly of SRAM, often occupies significant on-chip area of the CPU and consumes a huge portion of the CPU power, we propose a new method to reduce the power consumption of ...


Investigating Read/Write Aggregation To Exploit Power Reduction Opportunities Using Dual Supply Voltages, Gu Yunfei 2017 Washington University in St. Louis

Investigating Read/Write Aggregation To Exploit Power Reduction Opportunities Using Dual Supply Voltages, Gu Yunfei

Engineering and Applied Science Theses & Dissertations

Power consumption plays an important role in computer system design today. On-chip memory structures such as multi-level cache make up a significant proportion of total power consumption of CPU or Application-Specific Integrated Circuit (AISC) chip, especially for memory-intensive application, such as floating-point computation and machine learning algorithm. Therefore, there is a clear motivation to reduce power consumption of these memory structures that are mostly consisting of Static Random-Access Memory (SRAM) blocks. In this defense, I will present the framework of a novel dual-supply-voltage scheme that uses separate voltage levels for memory read and write operations. By quantitatively analyzing the cache ...


Particle Enrichment In Longitudinal Standing Bulk Acoustic Wave Microfluidics, Mingyang Cui 2017 Washington University in St. Louis

Particle Enrichment In Longitudinal Standing Bulk Acoustic Wave Microfluidics, Mingyang Cui

Engineering and Applied Science Theses & Dissertations

Separation, isolation, and enrichment of targeted nano- and microparticles are critical to a variety of biomedical applications from clinical research (development of therapeutics and diagnostics) to fundamental investigations that require concentration of specific cells from culture, separation of target species from heterogenous mixtures, or controlled perturbation of cells and microorganisms to determine their response to stimuli. Numerous techniques are available for bench-scale and medical settings; however, these traditional approaches are often labor intensive, time-consuming, costly, and/or require modification of the target. Efficiency and specificity are also lacking. Recently, techniques that exploit the similar scales of microfluidic technologies and the ...


2016 "Meeting Of The Minds" Research Symposium Abstracts, 2017 California State University, San Bernardino

2016 "Meeting Of The Minds" Research Symposium Abstracts

OSR Journal of Student Research

No abstract provided.


Artificial Islands In The South China Sea, Aaron Holmes 2017 California State University, San Bernardino

Artificial Islands In The South China Sea, Aaron Holmes

OSR Journal of Student Research

The purpose of this study was to understand the value and implications of artificial islands constructed by the People's Republic of China (PRC) in the South China Sea. Qualitative analysis was used with the available literature, sources, and treaties of the topics concerned. The paper concludes that the PRC gains many benefits primarily within the realm of energy security and explores what effects they may


The Face That Launched A Thousand Ships: Helen Of Troy In The Poetry Of Atwood And Tufts, Alea Walstrom 2017 California State University, San Bernardino

The Face That Launched A Thousand Ships: Helen Of Troy In The Poetry Of Atwood And Tufts, Alea Walstrom

OSR Journal of Student Research

This paper considers the transformation of Greek myth over time, how character’s attributes change over time, and ultimately how contemporary poets employ these myths. The myth of focus in the paper is that of Helen of Troy and the depiction of her character throughout the many years and variations of the myth. Her character is then considered in the contemporary feminist poetry of Carol Tufts and Margaret Atwood.


Self-Assembled Levitating Clusters Of Water Droplets: Pattern-Formation And Stability, Alexander A. Fedorets, Mark Frenkel, Evgeny Shulzinger, Leonid A. Dombrovsky, Edward Bormashenko, Michael Nosonovsky 2017 Tyumen State University

Self-Assembled Levitating Clusters Of Water Droplets: Pattern-Formation And Stability, Alexander A. Fedorets, Mark Frenkel, Evgeny Shulzinger, Leonid A. Dombrovsky, Edward Bormashenko, Michael Nosonovsky

Mechanical Engineering Faculty Articles

Water forms ordered hexagonally symmetric structures (snow crystals) in its solid state, however not as liquid. Typically, mists and clouds are composed of randomly moving small droplets lacking any ordered structure. Self-organized hexagonally patterned microdroplet clusters over locally heated water surfaces have been recently observed. However, many aspects of the phenomenon are far from being well understood including what determines droplets size, arrangement, and the distance between them. Here we show that the Voronoi entropy of the cluster tends to decrease indicating to their selforganization, while coupling of thermal effects and mechanical forces controls the stability of the clusters. We ...


Vehicle Occupancy Detection System, Hannah Miller, Justin Wert, Kelsey Lunberg 2017 University of Wyoming

Vehicle Occupancy Detection System, Hannah Miller, Justin Wert, Kelsey Lunberg

Honors Theses AY 16/17

Personal vehicles often become traps for unattended occupants throughout the year. Sadly, this can lead to severe health complications or even death if exposed for too long. Although these complications arise primarily in hot climates, it has been demonstrated that they can happen in any environment. Prolonged exposure to an unfamiliar and often dangerous setting without competent human intervention can be detrimental to health. This problem predominantly impacts pets and young children. In an effort to reduce these preventable health complications and possible deaths, we have developed a vehicle occupancy detection system.

The goal of developing this occupancy detection system ...


Flash Gas Management Analysis, Joshua T. Knight, Tayln M. Costello 2017 University of Wyoming

Flash Gas Management Analysis, Joshua T. Knight, Tayln M. Costello

Honors Theses AY 16/17

The petroleum industry is always evolving and improving, both in profitability and environmental responsibility. Jonah Energy in Pinedale, Wyoming is a on the cutting edge of that innovation. As a senior design team, they have asked us to specifically investigate the economic viability of different flash gas management solutions.

The first option is to install a Vapor Recovery Unit (VRU). This unit routes the flash gas through a scrubber for dehydration, through a compressor for pressurization and then into the sales line. This is both economically and environmentally more beneficial than flaring the gas. However, certain flash gas rates are ...


Microgravity Test Platform - Controls Team, Nicholas Hein 2017 University of Wyoming

Microgravity Test Platform - Controls Team, Nicholas Hein

Honors Theses AY 16/17

The overall goal of the NASA Microgravity project is to provide a low-cost alternative to current microgravity testing procedures for space-bound objects. The microgravity project examines a novel idea. The expense and wait lists that come with other microgravity testing methods creates a market potential for this modular system. The aim of the microgravity project is to achieve a microgravity environment though the free-fall of a monocoque containing a testing compartment for CubeSats. The higher the quality of the microgravity environment, the more customers will pay for the testing services. The Controls Group focused on using a reaction wheel system ...


دینامیک سیستم های قدرت, Hadi Zayandehroodi 2017 Department of Electrical Engineering, Kerman Branch, Islamic Azad University, Kerman, Iran

دینامیک سیستم های قدرت, Hadi Zayandehroodi

Dr. Hadi Zayandehroodi

No abstract provided.


Real-Time Atomistic Observation Of Structural Phase Transformations In Individual Hafnia Nanorods, Bethany M. Hudak, Sean W. Depner, Gregory R. Waetzig, Anjana Talapatra, Raymundo Arroyave, Sarbajit Banerjee, Beth S. Guiton 2017 University of Kentucky

Real-Time Atomistic Observation Of Structural Phase Transformations In Individual Hafnia Nanorods, Bethany M. Hudak, Sean W. Depner, Gregory R. Waetzig, Anjana Talapatra, Raymundo Arroyave, Sarbajit Banerjee, Beth S. Guiton

Chemistry Faculty Publications

High-temperature phases of hafnium dioxide have exceptionally high dielectric constants and large bandgaps, but quenching them to room temperature remains a challenge. Scaling the bulk form to nanocrystals, while successful in stabilizing the tetragonal phase of isomorphous ZrO2, has produced nanorods with a twinned version of the room temperature monoclinic phase in HfO2. Here we use in situ heating in a scanning transmission electron microscope to observe the transformation of an HfO2 nanorod from monoclinic to tetragonal, with a transformation temperature suppressed by over 1000°C from bulk. When the nanorod is annealed, we observe with atomic-scale ...


Network Congestion Effect Of E-Hailing Transportation Services, Xuegang Ban 2017 University of Washington

Network Congestion Effect Of E-Hailing Transportation Services, Xuegang Ban

TREC Friday Seminar Series

E-hailing plays a key role in emerging transportation services such as ridesourcing, ridesharing and taxis, among others. This seminar will present a general economic model to analyze the congestion effect of e-hailing services in a transportation network.

The model can help analyze customers’ choices of different modes, based on their value of time and the charging schemes of different services, as well as the overall impact of the services to network level congestion.


The Dry Reforming Of Methane To Syngas And Subsequent Products, Sean Kasprisin 4347974, Timothy Poppert, Nykyta Vovk, Alexander Fox, Hussain Alsukairi 2017 University of Wyoming

The Dry Reforming Of Methane To Syngas And Subsequent Products, Sean Kasprisin 4347974, Timothy Poppert, Nykyta Vovk, Alexander Fox, Hussain Alsukairi

Honors Theses AY 16/17

Dry Reforming of Methane to Syngas other Subsequent Products

Hussain Alsukairi, Alexander Fox, Sean Kasprisin, Tim Poppert, Nykta Vovk

Chemical Engineering

University of Wyoming

Senior Design

Synthesis Gas, or syngas (a combination of Hydrogen and Carbon Monoxide) can be used in a plethora of different chemical processes and processing plants. Utilizing Steam reforming of methane has been the accepted method to create syngas and it utilized on an industrial scale. Steam reforming of methane results in the formation of Carbon Dioxide (a greenhouse gas) that has to be dealt with so the impact on the environment can be minimized. Dry-reforming ...


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