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Articles 49861 - 49890 of 196983

Full-Text Articles in Engineering

Effects Of Alloy Composition And Solid-State Diffusion Kinetics On Powder Bed Fusion Cracking Susceptibility, Holden Hyer, Le Zhou, Abhishek Mehta, Yongho Sohn Feb 2021

Effects Of Alloy Composition And Solid-State Diffusion Kinetics On Powder Bed Fusion Cracking Susceptibility, Holden Hyer, Le Zhou, Abhishek Mehta, Yongho Sohn

Mechanical Engineering Faculty Research and Publications

Laser powder bed fusion (LPBF) has demonstrated its unique ability to produce customized, complex engineering components. However, processing of many commercial Al-alloys by LPBF remains challenging due to the formation of solidification cracking, although they are labelled castable or weldable. In order to elucidate this divergence, solidification cracking susceptibility from the steepness of the solidification curves, specifically |dT⁄dfs1⁄2|, as the fraction solidified nears 1 towards complete solidification, was calculated via Scheil–Gulliver model as a function of solute concentration in simple binary Al-Si, Al-Mg, and Al-Cu systems. Introduction of “diffusion in solid” into Scheil–Gulliver model resulted in a …

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A Single-Stage Passive Vibration Isolation System For Scanning Tunneling Microscopy, Toan T. Le Feb 2021

A Single-Stage Passive Vibration Isolation System For Scanning Tunneling Microscopy, Toan T. Le

Master's Theses

Scanning Tunneling Microscopy (STM) uses quantum tunneling effect to study the surfaces of materials on an atomic scale. Since the probe of the microscope is on the order of nanometers away from the surface, the device is prone to noises due to vibrations from the surroundings. To minimize the random noises and floor vibrations, passive vibration isolation is a commonly used technique due to its low cost and simpler design compared to active vibration isolation, especially when the entire vibration isolation system (VIS) stays inside an Ultra High Vacuum (UHV) environment. This research aims to analyze and build a single-stage …

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The Hot Cracking Susceptibility Subjected The Laser Beam Oscillation Welding On 6xxx Aluminum Alloy With A Partial Penetration Joint, Minjung Kang, Jason Cheon, Dong Hyuck Kam, Cheolhee Kim Feb 2021

The Hot Cracking Susceptibility Subjected The Laser Beam Oscillation Welding On 6xxx Aluminum Alloy With A Partial Penetration Joint, Minjung Kang, Jason Cheon, Dong Hyuck Kam, Cheolhee Kim

Mechanical and Materials Engineering Faculty Publications and Presentations

A laser beam oscillation method using Galvano mirrors, which allows wide weld beads and controls thermal stress distribution, was suggested to suppress the formation of solidification cracks in laser welds. In order to understand the solidification cracking behavior in relation to the bead shape, laser beam oscillation welding was performed under various oscillation widths and frequency conditions. To evaluate the effect of the oscillation parameter on solidification cracking susceptibility, a regression analysis based on the shape of the bead was performed. Stress distribution generated during the laser beam oscillation welding process was also analyzed using finite element modeling simulation. From …

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Somatosensory Deafferentation Reveals Lateralized Roles Of Proprioception In Feedback And Adaptive Feedforward Control Of Movement And Posture, S.A.L. Jayasinghe, F. R. Sarlegna, Robert A. Scheidt, R. L. Sainburg Feb 2021

Somatosensory Deafferentation Reveals Lateralized Roles Of Proprioception In Feedback And Adaptive Feedforward Control Of Movement And Posture, S.A.L. Jayasinghe, F. R. Sarlegna, Robert A. Scheidt, R. L. Sainburg

Biomedical Engineering Faculty Research and Publications

Proprioception provides crucial information necessary for determining limb position and movement, and plausibly also for updating internal models that might underlie the control of movement and posture. Seminal studies of upper-limb movements in individuals living with chronic, large fiber deafferentation have provided evidence for the role of proprioceptive information in the hypothetical formation and maintenance of internal models to produce accurate motor commands. Vision also contributes to sensorimotor functions but cannot fully compensate for proprioceptive deficits. More recent work has shown that posture and movement control processes are lateralized in the brain, and that proprioception plays a fundamental role in …

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Enhancing Reproductive Organ Segmentation In Pediatric Ct Via Adversarial Learning, Chi Nok Enoch Kan, Taly Gilat-Schmidt, Dong Hye Ye Feb 2021

Enhancing Reproductive Organ Segmentation In Pediatric Ct Via Adversarial Learning, Chi Nok Enoch Kan, Taly Gilat-Schmidt, Dong Hye Ye

Biomedical Engineering Faculty Research and Publications

Accurately segmenting organs in abdominal computed tomography (CT) scans is crucial for clinical applications such as pre-operative planning and dose estimation. With the recent advent of deep learning algorithms, many robust frameworks have been proposed for organ segmentation in abdominal CT images. However, many of these frameworks require large amounts of training data in order to achieve high segmentation accuracy. Pediatric abdominal CT images containing reproductive organs are particularly hard to obtain since these organs are extremely sensitive to ionizing radiation. Hence, it is extremely challenging to train automatic segmentation algorithms on organs such as the uterus and the prostate. …

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2021 Final Butte Reduction Works (Brw) Phase I Quality Assurance Project Plan (Qapp) Revision 3. February 2021, Pioneer Technical Services, Inc. Feb 2021

2021 Final Butte Reduction Works (Brw) Phase I Quality Assurance Project Plan (Qapp) Revision 3. February 2021, Pioneer Technical Services, Inc.

Silver Bow Creek/Butte Area Superfund Site

No abstract provided.

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Numerical Study Of The Phase Behavior Of Rod-Like Colloidal Particles With Attractive Tips, Justin T. Jack, Paul C. Millett Feb 2021

Numerical Study Of The Phase Behavior Of Rod-Like Colloidal Particles With Attractive Tips, Justin T. Jack, Paul C. Millett

Mechanical Engineering Faculty Publications and Presentations

Suspensions of anisometric particles are known to self-assemble into various liquid crystal (LC) phases, namely, the nematic, smectic (A or B or both), and in some cases, columnar phases, due to the effects of excluded volume. For some applications, LC phases with higher degrees of order are desired, but due to the fact that these phases generally exist at larger volume fractions, they can be difficult to handle experimentally. Here, we explore the effect of a weak attractive interaction localized at the tips of rod-like particles on the phase behavior of these suspensions. We perform large-scale molecular dynamics simulations of …

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Energy And Greenhouse Gas Savings For Leed-Certified U.S. Office Buildings, John H. Scofield, Susannah Brodnitz, Jakob Cornell, Tian Liang, Thomas Scofield Feb 2021

Energy And Greenhouse Gas Savings For Leed-Certified U.S. Office Buildings, John H. Scofield, Susannah Brodnitz, Jakob Cornell, Tian Liang, Thomas Scofield

University Faculty Publications and Creative Works

In this work, we present results from the largest study of measured, whole-building energy performance for commercial LEED-certified buildings, using 2016 energy use data that were obtained for 4417 commercial office buildings (114 million m2 ) from municipal energy benchmarking disclosures for 10 major U.S. cities. The properties included 551 buildings (31 million m2 ) that we identified as LEED-certified. Annual energy use and greenhouse gas (GHG) emission were compared between LEED and non-LEED offices on a city-by-city basis and in aggregate. In aggregate, LEED offices demonstrated 11% site energy savings but only 7% savings in source energy and GHG …

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Structural Identification And Damage Detection In Bridges Using Wave Method And Uniform Shear Beam Models: A Feasibility Study, Mehran Rahmani, Manan Naik Feb 2021

Structural Identification And Damage Detection In Bridges Using Wave Method And Uniform Shear Beam Models: A Feasibility Study, Mehran Rahmani, Manan Naik

Mineta Transportation Institute

This report presents a wave method to be used for the structural identification and damage detection of structural components in bridges, e.g., bridge piers. This method has proven to be promising when applied to real structures and large amplitude responses in buildings (e.g., mid-rise and high-rise buildings). This study is the first application of the method to damaged bridge structures. The bridge identification was performed using wave propagation in a simple uniform shear beam model. The method identifies a wave velocity for the structure by fitting an equivalent uniform shear beam model to the impulse response functions of the recorded …

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Environmental Exposures In Singapore Schools: An Ecological Study, Divya Periyakoil, Prasanna Hari Das, Clayton Miller, J. Costas Spanos, Ndola Prata Feb 2021

Environmental Exposures In Singapore Schools: An Ecological Study, Divya Periyakoil, Prasanna Hari Das, Clayton Miller, J. Costas Spanos, Ndola Prata

Research Collection College of Integrative Studies

Global climate change is a clear and present danger to our environment, but the impacts of climate change on human health are less known. People in Asian countries are more susceptible to the negative impacts of climate change and the subsequent environmental exposures because of the high population density, rapid urbanization, and natural geography of the region. The objective of this multidisciplinary collaborative ecological study was to explore the impact of environmental exposures such as temperature (°C), noise (db), humidity (%rh), air conditioning exposure time (hours), and distance traveled to school (km) on the comfort and academic success of school …

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Quantifying The Impact Of Uncertainty In Embedded Systems Mapping For Noc Based Architectures, Wenkai Guan, Milad Ghorbani Moghaddam, Cristinel Ababei Feb 2021

Quantifying The Impact Of Uncertainty In Embedded Systems Mapping For Noc Based Architectures, Wenkai Guan, Milad Ghorbani Moghaddam, Cristinel Ababei

Electrical and Computer Engineering Faculty Research and Publications

We describe a modeling framework to capture and account for uncertainty in design parameters in embedded systems. We then develop an uncertainty-aware solution to the problem of mapping in embedded systems that uses Network-on-Chip (NoC) based architecture platforms. The problem of mapping is formulated as a multi-objective - reliability, performance, and energy consumption - optimization problem. To solve this problem, we propose a solution based on the NSGA-II genetic algorithm and Monte Carlo simulation techniques. The solution is implemented as a computer-aid design tool that can generate robust 3D Pareto frontiers in the solution space formed by the design objectives …

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Zynq System-On-Chip Dma Messaging For Processor Monitoring, Daniel F. Koranek, Douglas D. Hodson, Scott R. Graham Feb 2021

Zynq System-On-Chip Dma Messaging For Processor Monitoring, Daniel F. Koranek, Douglas D. Hodson, Scott R. Graham

Faculty Publications

Xilinx Zynq-7000 System-on-Chip architectures combine an ARM Cortex-A9 core with an FPGA fabric. One benefit of this hybrid architecture is that it allows fast prototyping of designs where the security of either the processing system (PS) is monitored by the programmable logic (PL) or vice versa. The choice of implementing a design in the PS or PL is driven by cost-to-benefit analysis across many factors. This effort examines the design process required to construct security monitoring designs that use both the PS and PL. For background, this effort reviews similar security monitoring projects. For the effort, a PL peripheral was …

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A Life Cycle Comparison Of Remote, Deployed Expeditionary Waste Management Scenarios, David J. Chester, Chandrani Mukherjee, Jeremy M. Slagley, Eric Mbonimpa, Thomas Hornstein Feb 2021

A Life Cycle Comparison Of Remote, Deployed Expeditionary Waste Management Scenarios, David J. Chester, Chandrani Mukherjee, Jeremy M. Slagley, Eric Mbonimpa, Thomas Hornstein

Faculty Publications

The current barrier to acquisition and utilization of viable waste-to-energy (WTE) technologies at remote or deployed expeditionary sites requires high capital and operation & maintenance costs. The impacts to environment and human health of differing expeditionary waste management strategies were compared using the Life Cycle Assessment software SimaPro 8.0. Emissions of individual waste management scenarios were compiled from peer-reviewed literature, converted to values compatible with SimaPro’s waste scenario inputs, and the calculated impacts compared using SimaPro’s pre-loaded methodologies. These calculated impacts and the economic impacts confirm that open-air burning of waste is not only dangerous to humans and the environment, …

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Photoinduced Trapping Of Charge At Sulfur Vacancies And Copper Ions In Photorefractive Sn2P2S6 Crystals, Timothy D. Gustafson, Eric M. Golden, Elizabeth M. Scherrer, Nancy C. Giles, A. A. Grabar, Sergey A. Basun, Jonathan E. Slagle [*], Larry E. Halliburton Feb 2021

Photoinduced Trapping Of Charge At Sulfur Vacancies And Copper Ions In Photorefractive Sn2P2S6 Crystals, Timothy D. Gustafson, Eric M. Golden, Elizabeth M. Scherrer, Nancy C. Giles, A. A. Grabar, Sergey A. Basun, Jonathan E. Slagle [*], Larry E. Halliburton

Faculty Publications

Electron paramagnetic resonance (EPR) is used to monitor photoinduced changes in the charge states of sulfur vacancies and Cu ions in tin hypothiodiphosphate. A Sn2P2S6 crystal containing Cu+ (3d10) ions at Sn2+ sites was grown by the chemical vapor transport method. Doubly ionized sulfur vacancies (V2+S) are also present in the as-grown crystal (where they serve as charge compensators for the Cu+ ions). For temperatures below 70 K, exposure to 532 or 633 nm laser light produces stable Cu2+ (3d9) ions, as electrons move from Cu+ ions to …

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Sparc: Statistical Performance Analysis With Relevance Conclusions, Justin C. Tullos, Scott R. Graham, Jeremy D. Jordan, Pranav R. Patel Feb 2021

Sparc: Statistical Performance Analysis With Relevance Conclusions, Justin C. Tullos, Scott R. Graham, Jeremy D. Jordan, Pranav R. Patel

Faculty Publications

The performance of one computer relative to another is traditionally characterized through benchmarking, a practice occasionally deficient in statistical rigor. The performance is often trivialized through simplified measures, such as the approach of central tendency, but doing so risks a loss of perspective of the variability and non-determinism of modern computer systems. Authentic performance evaluations are derived from statistical methods that accurately interpret and assess data. Methods that currently exist within performance comparison frameworks are limited in efficacy, statistical inference is either overtly simplified or altogether avoided. A prevalent criticism from computer performance literature suggests that the results from difference …

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An Assessment Of The Spatial Variation Of Isotopic Ratios In A Candu Reactor For Nuclear Treaty Monitoring, Aaron W. Burkhardt, James E. Bevins, Stephen H. Baxter Feb 2021

An Assessment Of The Spatial Variation Of Isotopic Ratios In A Candu Reactor For Nuclear Treaty Monitoring, Aaron W. Burkhardt, James E. Bevins, Stephen H. Baxter

Faculty Publications

A 3-D Quarter-Core CANDU-6 is modeled using Serpent 2 for nuclear treaty monitoring. The spatial variation of flux spectra and isotopic concentrations is analyzed to determine the potential isotopic distribution of key radionuclides from standard reactor operations relevant to non-proliferation. The initial results of the model show a 46% difference in overall flux magnitude throughout the core as well as a 2-30% difference in discrete energy flux. The coupled production rate (magnitude) and spectral differences can contribute to significant spatial variations in isotope ratios throughout the core. Initial results indicate 239 Pu/ 240 Pu ratios vary by as much as …

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Economics Of Grid-Tied Solar Photovoltaic Systems Coupled To Heat Pumps: The Case Of Northern Climates Of The U.S. And Canada, Joshua M. Pearce, Nelson Sommerfeldt Feb 2021

Economics Of Grid-Tied Solar Photovoltaic Systems Coupled To Heat Pumps: The Case Of Northern Climates Of The U.S. And Canada, Joshua M. Pearce, Nelson Sommerfeldt

Michigan Tech Publications, Part 1

Solar photovoltaic (PV) technology is now a profitable method to decarbonize the grid, but if catastrophic climate change is to be avoided, emissions from transportation and heating must also decarbonize. One approach to renewable heating is leveraging improvements in PV with heat pumps (HPs). To determine the potential for PV+HP systems in northern areas of North America, this study performs numerical simulations and economic analysis using the same loads and climate, but with local electricity and natural gas rates for Sault Ste. Marie, in both Canada and U.S. Ground-mounted, fixed-tilt, grid-tied PV systems are sized to match 100% of electric …

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Campus Carbon Footprint Study At A South Texas University, Monica Garcia, Christian Florez, Diego Lopez, Jongmin Kim, Maysam Pournik Feb 2021

Campus Carbon Footprint Study At A South Texas University, Monica Garcia, Christian Florez, Diego Lopez, Jongmin Kim, Maysam Pournik

Mechanical Engineering Faculty Publications

A campus carbon footprint study was conducted at the University of Texas Rio Grande Valley, a Southern Texan university. This initiative was the school’s strategic plan to set a baseline for overall campus resource utilization status as well as to answer global requests to track and reduce campus greenhouse gas emissions and achieve greater sustainability on campus. For fiscal years of 2016 to 2018, an overall increase of campus carbon footprint was about 0.6%. The biggest increase was observed from sources owned or controlled by the school while the emissions associated with power usage decreased. The university’s carbon footprint was …

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The Role Of Bed-Penetrating Kelvin–Helmholtz Vortices On Local And Instantaneous Bedload Sediment Transport, Liheng Guan, J. S. Salinas, ‪Nadim Zgheib, S. Balachandar Feb 2021

The Role Of Bed-Penetrating Kelvin–Helmholtz Vortices On Local And Instantaneous Bedload Sediment Transport, Liheng Guan, J. S. Salinas, ‪Nadim Zgheib, S. Balachandar

Mechanical Engineering Faculty Publications

We present results from open-channel, Euler–Lagrange (EL) simulations of turbulent flow over an erodible particle bed at a shear Reynolds number of Reτ=180 . Upon space and time averaging, our simulations correctly reproduce the Wong & Parker (ASCE J. Hydraul. Engng, vol. 132, issue 11, 2006, pp. 1159–1168) bedload transport relation (WP). However, local and instantaneous sediment flux shows orders of magnitude scatter around the WP prediction. Visualization of the vortical structures using swirling strength shows the existence of bed-penetrating Kelvin–Helmholtz (KH) vortex packets, which coupled with particle inertia are primarily responsible for the large scatter. The results also show …

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Decoupling Of Antennas With Adjacent Frequency Bands Using Cascaded Decoupling Network, Min Li, Min Wang, Lijun Jiang, Lawrence Kwan Yeung Feb 2021

Decoupling Of Antennas With Adjacent Frequency Bands Using Cascaded Decoupling Network, Min Li, Min Wang, Lijun Jiang, Lawrence Kwan Yeung

Electrical and Computer Engineering Faculty Research & Creative Works

This communication presents a novel decoupling device called a cascaded power dividing decoupling network (C-PDDN). It is cascaded with two antennas operating in adjacent or even contiguous frequency bands to reduce the mutual coupling. To achieve high isolations at n desired frequency points, an n -order C-PDDN can be accordingly designed. Each order PDDN consists of two power dividers (PDs), two sections of transmission lines, and one reactive component. Explicit design formulas are presented to calculate the design parameters of the C-PDDN to meet the required isolation criteria. To validate the decoupling concept, a two-order C-PDDN is designed and applied …

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Non-Prehensile Manipulation Of A Devil-Stick: Planar Symmetric Juggling Using Impulsive Forces, Nilay Kant, Ranjan Mukherjee Feb 2021

Non-Prehensile Manipulation Of A Devil-Stick: Planar Symmetric Juggling Using Impulsive Forces, Nilay Kant, Ranjan Mukherjee

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Juggling a devil-stick can be described as a problem of non-prehensile manipulation. Assuming that the devil-stick remains confined to the vertical plane, the problem of juggling the stick between two symmetric configurations is considered. Impulsive forces are applied to the stick intermittently and the impulse of the force and its point of application are modeled as control inputs to the system. The dynamics of the devil-stick due to the impulsive forces and gravity is described by half-return maps between two Poincaré sections; the symmetric configurations are fixed points of these sections. A coordinate transformation is used to convert the juggling …

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Absorption Of Nitrogen During Pulsed Wave L-Pbf Of 17-4 Ph Steel, Ben Brown, Joseph William Newkirk, Frank W. Liou Feb 2021

Absorption Of Nitrogen During Pulsed Wave L-Pbf Of 17-4 Ph Steel, Ben Brown, Joseph William Newkirk, Frank W. Liou

Materials Science and Engineering Faculty Research & Creative Works

In the fabrication of 17-4 PH by laser powder bed fusion (L-PBF) the well-documented occurrence of large amounts of retained austenite can be attributed to an elevated concentration of nitrogen present in the material. While the effects of continuous wave (CW) laser processing on in-situ nitrogen absorption characteristics have been evaluated, power modulated pulsed wave (PW) laser processing effects have not. In this study the effects of PW L-PBF processing of 17-4 PH on nitrogen absorption, phase composition, and mechanical performance are explored using commercially available PW L-PBF equipment and compared to samples produced by CW L-PBF. PW L-PBF samples …

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Mixed Matrix Membranes For Sustainable Electrical Energy-Saving Applications, Hossein Riasat Harami, Farid Amirkhani, Hossein Abedsoltan, Mohammad Younas, Mashallah Rezakazemi, Mahdi Sheikh, Saeed Shirazian Feb 2021

Mixed Matrix Membranes For Sustainable Electrical Energy-Saving Applications, Hossein Riasat Harami, Farid Amirkhani, Hossein Abedsoltan, Mohammad Younas, Mashallah Rezakazemi, Mahdi Sheikh, Saeed Shirazian

Chemical and Biochemical Engineering Faculty Research & Creative Works

This work presents a technical investigation and review of the development of mixed matrix membranes (MMMs) employed in different applications to save electrical energy. The MMMs design has been recently adjusted and improved to restore more energy bulks. The important factors to control the performance of the MMMs are the penetrant type, membrane matrix, and polymer-filler interface interactions. This study reviews the current methods to deal with dielectric MMMs and smart nanomembranes for energy saving. These methods include ferroelectric membrane fabrication, dielectric permittivity, conductive dopants, construction of nanocomposites with modified surfaces, and the usage of combined effects. Most chemists and …

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A High-Temperature-Resistant Inorganic Matrix For Concrete Structures Enhanced By Fiber-Reinforced Polymer, Jing Zhu, Wenzhong Zheng, Lili Xie, Lesley Sneed Feb 2021

A High-Temperature-Resistant Inorganic Matrix For Concrete Structures Enhanced By Fiber-Reinforced Polymer, Jing Zhu, Wenzhong Zheng, Lili Xie, Lesley Sneed

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

This paper probed deep into a high-temperature resistant inorganic matrix: alkali-activated slag cement (AASC), which is a kind of cementitious material prepared by alkali-activator and pozzolanic or latent hydraulic material. Firstly, the mix ratio of the AASC was optimized to improve the wettability and mechanical properties. Then, the effects of the adhesive matrix and the type of fiber-reinforced polymer (FRP) were observed through FRP-to-concrete bond tests on 93 specimens. The test results, coupled with anchorage analysis, indicate that the AASC has comparable reinforcing effects as those of organic epoxy matrix; the anchorage length of FRP sheets has a significant influence …

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Bone Cement As A Local Chemotherapeutic Drug Delivery Carrier In Orthopedic Oncology: A Review, Sunjeev S. Phull, Alireza Rahimnejad Yazdi, Michelle Ghert, Mark R. Towler Feb 2021

Bone Cement As A Local Chemotherapeutic Drug Delivery Carrier In Orthopedic Oncology: A Review, Sunjeev S. Phull, Alireza Rahimnejad Yazdi, Michelle Ghert, Mark R. Towler

Chemical and Biochemical Engineering Faculty Research & Creative Works

Metastatic bone lesions are common among patients with advanced cancers. While chemotherapy and radiotherapy may be prescribed immediately after diagnosis, the majority of severe metastatic bone lesions are treated by reconstructive surgery, which, in some cases, is followed by postoperative radiotherapy or chemotherapy. However, despite recent advancements in orthopedic surgery, patients undergoing reconstruction still have the risk of developing severe complications such as tumor recurrence and reconstruction failure. This has led to the introduction and evaluation of poly (methyl methacrylate) and inorganic bone cements as local carriers for chemotherapeutic drugs (usually, antineoplastic drugs (ANPDs)). The present work is a critical …

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In Vitro Evaluation Of Novel Titania-Containing Borate Bioactive Glass Scaffolds, Romina Shafaghi, Omar Rodriguez, Anthony W. Wren, Loraine Chiu, Emil H. Schemitsch, Paul Zalzal, Stephen D. Waldman, Marcello Papini, Mark R. Towler Feb 2021

In Vitro Evaluation Of Novel Titania-Containing Borate Bioactive Glass Scaffolds, Romina Shafaghi, Omar Rodriguez, Anthony W. Wren, Loraine Chiu, Emil H. Schemitsch, Paul Zalzal, Stephen D. Waldman, Marcello Papini, Mark R. Towler

Chemical and Biochemical Engineering Faculty Research & Creative Works

Titanium-containing borate bioactive glass scaffolds (0, 5, 15, and 20 mol %, identified as BRT0, BRT1, BRT3, and BRT4) with a microstructure similar to that of human trabecular bone were prepared and evaluated in vitro for potential bone loss applications in revision total knee arthroplasty (rTKA). Methyl thiazolyl tetrazolium (MTT) cell viability assays of scaffold ion release extracts revealed that BRT0 scaffolds (0 mol % titanium) inhibited cell proliferation and activity at day 14. At day 30, all scaffold extracts decreased cell proliferation and activity significantly. However, live/dead cell assay results demonstrated that degradation products from all the scaffolds had …

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Modeling And Analysis Of Microstrip Annular Ring Antenna With Capacitive Coupling Matching Network, Yan Li, Sheng Sun, Lijun Jiang, Buning Tian Feb 2021

Modeling And Analysis Of Microstrip Annular Ring Antenna With Capacitive Coupling Matching Network, Yan Li, Sheng Sun, Lijun Jiang, Buning Tian

Electrical and Computer Engineering Faculty Research & Creative Works

In this manuscript, microstrip annular ring antenna with capacitive coupling matching network is modeled and analyzed with equivalent circuit model and cavity model, which is simple and accurate for this structure. The proposed approach not only demonstrates physics lying behind the engineering design but also will be a good guideline for the microstrip annular ring antenna design. A prototype working UHF RFID band (902-928 MHz) is designed. Overall dimension of the proposed antenna is about 0.5λ0 x 0.5λ0 x 0.055λ0, and the realized gain is larger than 5 dB with axial ratio is smaller than 3 dB. The measured results …

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Effect Of Membrane Properties On The Carbonation Of Anion Exchange Membrane Fuel Cells, Yiwei Zheng, Lyzmarie Nicole Irizarry, Noor Ui Hassan, Eric R. Williams, Morgan Stefik, Jacob M. Lamanna, Daniel S. Hussey, Mustain E William Jan 2021

Effect Of Membrane Properties On The Carbonation Of Anion Exchange Membrane Fuel Cells, Yiwei Zheng, Lyzmarie Nicole Irizarry, Noor Ui Hassan, Eric R. Williams, Morgan Stefik, Jacob M. Lamanna, Daniel S. Hussey, Mustain E William

Faculty Publications

Anion exchange membrane fuel cells (AEMFC) are potentially very low-cost replacements for proton exchange membrane fuel cells. However, AEMFCs suffer from one very serious drawback: significant performance loss when CO2 is present in the reacting oxidant gas (e.g., air) due to carbonation. Although the chemical mechanisms for how carbonation leads to voltage loss in operating AEMFCs are known, the way those mechanisms are affected by the properties of the anion exchange membrane (AEM) has not been elucidated. Therefore, this work studies AEMFC carbonation using numerous high-functioning AEMs from the literature and it was found that the ionic conductivity of the …

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A Computational Study Of Cocrfeniti High Entropy Alloys: Phase Diagrams, Thermodynamics, And Mechanical Properties From Calphad And First Principles, Geraldine Anis Jan 2021

A Computational Study Of Cocrfeniti High Entropy Alloys: Phase Diagrams, Thermodynamics, And Mechanical Properties From Calphad And First Principles, Geraldine Anis

Theses and Dissertations

High entropy alloys (HEAs) are multi-component alloys, which are often defined as those consisting of at least 5 principal elements with concentrations ranging between 5 and 35 atomic weight percent (at.%). Since their introduction by Yeh et al. and Cantor et al. in 2004, HEAs have been found to possess many important properties and have become prime candidates for several high-performance applications such as high-temperature and biomedical applications. Despite their multi-principal element nature, many HEAs favor the formation of solid solution phases as opposed to the intermetallic phases expected for such systems. This was originally only attributed to their high …

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An Optimized Lte-Based Technique For Drone Base Station 3d Placement And Resource Allocation In Delay-Sensitive M2m Networks, Ahmed Fahim Jan 2021

An Optimized Lte-Based Technique For Drone Base Station 3d Placement And Resource Allocation In Delay-Sensitive M2m Networks, Ahmed Fahim

Theses and Dissertations

The deployment of drone-mounted communication systems has received increasing interest and attention recently as it allows significant improvement to the network access capacity and coverage. Many applications can benefit from such deployments in particular machine-to-machine (M2M) communications. Drones are expected to facilitate extending wireless network access for both human users and the smart machine-type-communication devices (MTCDs) that have strict and diverse quality of service (QoS) requirements. In this thesis, we propose an optimal solution for the dynamic placement of an LTE drone-mounted base station to maximize the coverage of MTCDs deployed over a large geographical area in disaster situations or …

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