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Articles 2671 - 2700 of 21777

Full-Text Articles in Engineering

Feasibility Of A Critical Experiment Utilizing Uranium Dioxide-Beryllium Oxide With Neutron Spectrum Shifting Capabilities, Ashley Rachel Raster Jan 2022

Feasibility Of A Critical Experiment Utilizing Uranium Dioxide-Beryllium Oxide With Neutron Spectrum Shifting Capabilities, Ashley Rachel Raster

Masters Theses

“The goal of this project is to determine the feasibility of utilizing Annular Core Research Reactor (ACRR) fuel in core design with Sandia Pulse Reactor Facility’s (SPRF) Seven Percent Critical Experiment (7uPCX) fuel rods as driver fuel for a critical experiment facility to support future critical and benchmark experiments for the International Criticality Safety Benchmark Evaluation Project (ICSBEP) handbook. This is part of the Critical Experiment Design (CED) process for future criticality experiments. These criticality experiment designs have the main goal of being performed in the same facility at different neutron energy ranges. To test the feasibility of this experiment …


Experimental Optimization Of Simulated Ring Rolling Operation For Heavy Rail Industry, Jacob M. Summers Jan 2022

Experimental Optimization Of Simulated Ring Rolling Operation For Heavy Rail Industry, Jacob M. Summers

Masters Theses

“Industrially cast AISI 1070 steel wheel pre-forms from Amsted Rail Co. were experimentally hot rolled to simulate the conditions for industrial wheel rolling. Ring rolling of near net shape castings can improve location specific properties by decreasing segregation, closing porosity, and reducing grain size without the use of multiple forging operations in a traditional forging line. As-cast wheel sections were subjected to thermomechanical processing routes using a 2-high rolling mill in a temperature range of 830°C to 1200°C. The goal being to simulate the ring rolling process and optimize benefits of mechanical properties of the as-rolled steel. Charpy V- and …


Validation Of Athlet-Cd With Cora-28 Test, Murat Tuter Jan 2022

Validation Of Athlet-Cd With Cora-28 Test, Murat Tuter

Masters Theses

“Following the incidents at Chernobyl and Fukushima, severe accidents at nuclear power plants (NPP) have become a global concern. These accidents generally occur because of a failure in the reactor cooling system (RCS) and result in the melting of the reactor core and fission product release. This event is mostly caused by a LOCA, loss of flow accident, station blackout or loss of heat sink. During a severe accident, generation of hydrogen as a result of steam-zircaloy fuel cladding is a significant safety concern. To better understand and prevent the hydrogen generation issue, safety related experiments and safety related codes …


Pressure Relief Wells: Analysis Of Subsurface Heterogeneity To Evaluate Relief Well Locations For Mississippi River Levees, Emma Marie Young Jan 2022

Pressure Relief Wells: Analysis Of Subsurface Heterogeneity To Evaluate Relief Well Locations For Mississippi River Levees, Emma Marie Young

Masters Theses

“When designing pressure relief well systems, it is imperative to understand what major geomorphology and heterogenies features are present, such as buried oxbow lakes, especially when the feature is parallel to the source, such as the Mississippi River. When present, there is a notable greater increase in head pressures, especially on the landward tow of the levee. This can cause erosional features that originally thought of to have been protected from by installing pressure relief wells. When comparing the effective hydraulic conductivities of horizontal clay layers and vertical clay layers spanning the length of the model, little to no noticeable …


Controlling Microalloy Interactions On Precipitation, Hot Ductility, And Microstructure -- Mechanical Property Relationships, Madhuri Varadarajan Jan 2022

Controlling Microalloy Interactions On Precipitation, Hot Ductility, And Microstructure -- Mechanical Property Relationships, Madhuri Varadarajan

Masters Theses

“One of the main problems faced in the continuous casting of micro-alloy steels is the formation of transverse cracks. Transverse cracks are surface, or near-surface cracks formed perpendicular to the casting direction. The research focuses on using laboratory hot tensile tests methods to determine the low ductility ranges in high strength steel grades with different micro-alloy additions of titanium, niobium, and vanadium. The hot ductility of commercially produced as-cast slab and beam blank samples was evaluated using two experimental methods: tensile testing utilizing a servo-hydraulic load frame with a resistance furnace and thermomechanical testing using rapid Joule heating. The tests …


Array Signal Processing For Source Localization And Enhancement, Sohel J. Patel Jan 2022

Array Signal Processing For Source Localization And Enhancement, Sohel J. Patel

Doctoral Dissertations

“A common approach to the wide-band microphone array problem is to assume a certain array geometry and then design optimal weights (often in subbands) to meet a set of desired criteria. In addition to weights, we consider the geometry of the microphone arrangement to be part of the optimization problem. Our approach is to use particle swarm optimization (PSO) to search for the optimal geometry while using an optimal weight design to design the weights for each particle’s geometry. The resulting directivity indices (DI’s) and white noise SNR gains (WNG’s) form the basis of the PSO’s fitness function. Another important …


Graphical Revamping Of A Crude Distillation Unit Under Two Variable Operational Scenarios - Naphtha Stabilizer And Reformer Operated, Amany G. Abo-Mousa, Dina A. Kamel, Hany A. Elazab, Mamdouh A. Gadalla, Mai K. Fouad Jan 2022

Graphical Revamping Of A Crude Distillation Unit Under Two Variable Operational Scenarios - Naphtha Stabilizer And Reformer Operated, Amany G. Abo-Mousa, Dina A. Kamel, Hany A. Elazab, Mamdouh A. Gadalla, Mai K. Fouad

Chemical and Biochemical Engineering Faculty Research & Creative Works

Energy costs represent significant parts of the total operating costs of crude refining industries. Energy integration is a typical solution to reduce heating and cooling utilities in crude refining plants through maximizing the target temperature of crude oil streams before entering the furnace. Over the past few decades, a significant progress has been made in energy integration methods including Pinch technology and mathematical programming approaches. Example of these is a graphical technique which plots Thot versus Tcold for energy analysis and revamping studies. The current research employs the Thot - Tcold diagrams in an algorithm to retrofit an existing crude …


Effect Of Açai Berry Extract Application On The Bond Strength To The Bleached Enamel Using An Experimental Etch-And-Rinse Adhesive, Lamiaa M. Moharam, Haidy N. Salem, Shahinaz N. Hassan Jan 2022

Effect Of Açai Berry Extract Application On The Bond Strength To The Bleached Enamel Using An Experimental Etch-And-Rinse Adhesive, Lamiaa M. Moharam, Haidy N. Salem, Shahinaz N. Hassan

Chemical and Biochemical Engineering Faculty Research & Creative Works

Background: To evaluate the bleached enamel shear bond strength (SBS) after antioxidants application using an experimental adhesive. Material and Methods: Sixty sound human molars had their roots removed then cut into buccal and lingual halves and mounted in acrylic blocks. Enamel bleaching was done using an in-office chemical bleaching agent. Specimens were arbitrarily allocated into 12 groups (n=10) regarding the three experimental levels of the study: two antioxidant agents [10% açai berry extract, 10% sodium ascorbate prepared gels (applied for 15-min) and the control group (no antioxidant application)], two adhesive materials [commercial etch-and-rinse (ER) adhesive and an experimental ER adhesive] …


Tension-Stiffening Effect Consideration For Modeling Deflection Of Cracked Reinforced Uhpc Beams, Le Teng, Rongling Zhang, Kamal Khayat Jan 2022

Tension-Stiffening Effect Consideration For Modeling Deflection Of Cracked Reinforced Uhpc Beams, Le Teng, Rongling Zhang, Kamal Khayat

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Tension-stiffening effects can significantly influence the flexural performance of cracked reinforced concrete specimens. Such effect is amplified for fiber-reinforced concrete, given the fact that fibers can bridge the cracks. The objective of this study was to develop a model to predict the deflection of cracked reinforced ultra-high performance concrete (R-UHPC) beam elements. The modeling approach characterized the average bending moment of inertia by combining the existing model used for conventional reinforced concrete and the analytical model of stress distribution of UHPC along the cross-section. The finite element analysis (FEA) was employed to evaluate the flexural deflection based on the average …


Optimizing Exterior Lighting Illuminance And Spectrum For Human, Environmental, And Economic Factors., S. M. Simmons, Stuart Werner Baur, William L. Gillis, Devin Michael Burns, Heath Pickerill Jan 2022

Optimizing Exterior Lighting Illuminance And Spectrum For Human, Environmental, And Economic Factors., S. M. Simmons, Stuart Werner Baur, William L. Gillis, Devin Michael Burns, Heath Pickerill

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

With the recent widespread adoption of LED lighting in outdoor areas, numerous concerns have been raised about the potential for harmful effects on humans, animals, plants, and the night sky. These stem from the high blue light content of some LED bulbs and an incentive to increase lighting levels caused by higher efficiency and lower costs. While new lighting installations are often described as environmentally friendly due to their energy efficiency, factors such as light pollution are often neglected or not given enough weight. This research focuses on optimizing the design of exterior lighting for human, environmental, and economic factors …


Maintenance Optimization In A Digital Twin For Industry 4.0, Abhijit Gosavi, Vy Khoi Le Jan 2022

Maintenance Optimization In A Digital Twin For Industry 4.0, Abhijit Gosavi, Vy Khoi Le

Engineering Management and Systems Engineering Faculty Research & Creative Works

The advent of Internet of Things and artificial intelligence in the era of Industry 4.0 has transformed decision-making within production systems. In particular, many decisions that previously required significant human activity are now made automatically with minimal human intervention via so-called digital twins (DTs). In the context of maintenance and reliability modeling, this naturally calls for new paradigms that can be seamlessly integrated within DTs for decision-making. The input data for time to failure needed in reliability computations are directly collected from the work center in a digital setting and often do not satisfy a known distribution. A neural network …


Extraction Of Stripline Surface Roughness Using Cross-Section Information And S-Parameter Measurements, Zeyi Sun, Jian Liu, Xiaoyan Xiong, Victor Khilkevich, Donghyun Kim, Darvl Beetner Jan 2022

Extraction Of Stripline Surface Roughness Using Cross-Section Information And S-Parameter Measurements, Zeyi Sun, Jian Liu, Xiaoyan Xiong, Victor Khilkevich, Donghyun Kim, Darvl Beetner

Engineering Management and Systems Engineering Faculty Research & Creative Works

To characterize additional conductor loss introduced by conductor surface roughness, various models have been proposed to describe the relationship between foil roughness levels and surface roughness correction factor. However, all these empirical or physical models require a PCB sample to be manufactured and analyzed in advance. The procedure requires dissecting the PCB and is time- and labor-consuming. To avoid such a process, a new surface roughness extraction process is proposed here. Only the measured S-parameter and nominal cross-sectional information of the board are needed to extract the roughness level of conductor foils. Besides, this method can also deal with boards …


Monte Carlo Particle Simulation Of Avalanche Breakdown In A Reverse Biased Diode With Full Band Structure, Zeyi Sun, Manish Kizhakkeveettil Mathew, Ryan From, Donghyun Kim Jan 2022

Monte Carlo Particle Simulation Of Avalanche Breakdown In A Reverse Biased Diode With Full Band Structure, Zeyi Sun, Manish Kizhakkeveettil Mathew, Ryan From, Donghyun Kim

Engineering Management and Systems Engineering Faculty Research & Creative Works

To model the avalanche breakdown of a voltage regulator diode under reverse bias, a computationally rigorous device physics model using the Monte Carlo method to solve charge carrier Boltzmann transport equations (BTEs) is proposed. The transport of energetic charge carriers is calculated by using the full energy band instead of the non-parabolic band structure. The position-dependent doping profile found in real diodes is modeled accurately and time-efficiently. A two-step method is introduced to accelerate the simulation of avalanche breakdown. With the proposed model, the expected IV characteristics of a voltage regulator diode under reverse bias are simulated. The transport of …


The Effects Of Mixing Multi-Component Hlw Glasses On Spinel Crystal Size, C. (Charmayne) E. Lonergan, J. Rice, C. Skidmore, M. J. Schweiger, P. Hrma Jan 2022

The Effects Of Mixing Multi-Component Hlw Glasses On Spinel Crystal Size, C. (Charmayne) E. Lonergan, J. Rice, C. Skidmore, M. J. Schweiger, P. Hrma

Materials Science and Engineering Faculty Research & Creative Works

The Hanford Waste Treatment and Immobilization Plant will vitrify radioactive waste into borosilicate glass. The high-level waste (HLW) glass formulations are constrained by processing and property requirements, including restrictions aimed at avoiding detrimental impacts of spinel crystallization in the melter. To understand the impact of glass chemistry on crystallization, two HLW glasses precipitating small (∼5 μm) spinel crystals were individually mixed and melted with a glass that precipitated large (∼45 μm) spinel crystals in ratios of 25, 50, and 75 wt.%. The size of spinel crystals in the mixed glasses varied from 5 to 20 μm. Small crystal size was …


The Role Of Microstructure On High-Temperature Oxidation Behavior Of Hafnium Carbide, Jonathan A. Scott, Xiaoqing He, David W. Lipke Jan 2022

The Role Of Microstructure On High-Temperature Oxidation Behavior Of Hafnium Carbide, Jonathan A. Scott, Xiaoqing He, David W. Lipke

Materials Science and Engineering Faculty Research & Creative Works

Microstructure development of the products formed upon oxidation of hafnium carbide (HfCx, x = 0.65, 0.81, or 0.94) at 1300°C and 0.8 mbar oxygen pressure was investigated using Raman spectroscopy, X-ray diffraction, electron microscopy, and electron energy-loss spectroscopy. For all specimens a multilayered oxide scale was observed featuring an outermost porous hafnia layer and an interlayer adjacent to the parent carbide containing hafnia interspersed with carbon. The outermost hafnia features coarse pores presumably formed during initial stages of oxidation to allow rapidly evolving gaseous products to escape from the oxidation front. As the oxidation scale thickens, diffusional resistance results in …


Fundamental Effects Of Al And Ta On Microstructure And Phase Transformations In The Al–Cr–Mo–Ta–Ti Refractory Complex Concentrated Alloy System, Austin E. Mann, Joseph William Newkirk Jan 2022

Fundamental Effects Of Al And Ta On Microstructure And Phase Transformations In The Al–Cr–Mo–Ta–Ti Refractory Complex Concentrated Alloy System, Austin E. Mann, Joseph William Newkirk

Materials Science and Engineering Faculty Research & Creative Works

The effect of aluminum and tantalum concentrations on a refractory metal complex concentrated alloy is reported, particularly with respect to their effect on microstructure and phase composition of the alloy in cast and annealed form. Alloys with an equiatomic composition, (AlCrMoTaTi), an aluminum-lean composition (Al0.75CrMoTaTi), and a tantalum-lean composition (AlCrMoTa0.75Ti) are produced via arc melting. The alloys exhibit multiphase structures, confirmed by X-ray diffraction, microstructural characterization, and thermal analysis. The minor off-equiatomic adjustments of aluminum and tantalum in this alloy system did not drastically alter the prevalence of the Cr–Ta-based Laves phase. Correlations between thermodynamic predictions and observed phase transformations …


Effect Of Spallation On Oxidation Kinetics Of Heat-Resistant Cr–Ni Austenitic Steels On Air And Combustion Atmosphere, Simon N. Lekakh, Oleg Neroslavsky, Mei Li, Larry Godlewski, Wenhui Zhu Jan 2022

Effect Of Spallation On Oxidation Kinetics Of Heat-Resistant Cr–Ni Austenitic Steels On Air And Combustion Atmosphere, Simon N. Lekakh, Oleg Neroslavsky, Mei Li, Larry Godlewski, Wenhui Zhu

Materials Science and Engineering Faculty Research & Creative Works

Thin-walled castings made from Cr–Ni austenitic steels offer a combination of light weight of a near-net component with significant high temperature corrosion protection by forming a surface oxide layer. However, above critical service conditions (temperature, atmosphere, thermal cycling), oxidized surface can result in intensive surface degradation due to scale spallation. Scale spallation can decrease the wall thickness which could be detrimental to the in-service life of thin-walled castings. Experiments and stochastic simulations of spallation assisted oxidation were performed with three cast austenitic heat-resistant steels having different Cr–Ni concentrations at temperatures between 900 and 1000 ℃ on air and water vapor …


On The Effect Of Hot Rolling On Inclusion Size And Distribution In A Cast Aisi 1070 Steel Railroad Wheel, Jacob M. Summers, Soumava Chakraborty, Laura Bartlett, Ronald J. O'Malley, Mario F. Buchely, Richard Pilon Jan 2022

On The Effect Of Hot Rolling On Inclusion Size And Distribution In A Cast Aisi 1070 Steel Railroad Wheel, Jacob M. Summers, Soumava Chakraborty, Laura Bartlett, Ronald J. O'Malley, Mario F. Buchely, Richard Pilon

Materials Science and Engineering Faculty Research & Creative Works

The goal of this work is to examine the effect of hot deformation on shrinkage porosity and nonmetallic inclusions in an AISI 1070 grade steel industrially produced wheel casting. Steel cleanliness is an important consideration as it influences the mechanical properties of the final product. A high density of porosity and inclusions have been shown to be detrimental for mechanical properties, especially during hot rolling. Using a laboratory-scale rolling mill, cast preforms were subjected to a 66% cumulative reduction to determine the effect of thermomechanical processing on void closure and inclusions that may produce anisotropy in mechanical properties. Quantitative automated …


An Awe-Enhanced Wideband Subdomain Dg-Rtc Algorithm In Solving Electromagnetic Problems, Shimin Liu, Li (Lijun) Jun Jiang, Ping Li Jan 2022

An Awe-Enhanced Wideband Subdomain Dg-Rtc Algorithm In Solving Electromagnetic Problems, Shimin Liu, Li (Lijun) Jun Jiang, Ping Li

Electrical and Computer Engineering Faculty Research & Creative Works

In this research, a Robin transmission condition enriched frequency-domain discontinuous Galerkin (DG-RTC) method is proposed to solve the electromagnetic problems. The proposed DG-RTC method directly discretizes the vector wave equation in each subdomain, and the numerical flux is used for the information communication of solutions between neighbor subdomains. Compared with the traditional Maxwell's equations-based DG (ME-DG) method, the proposed DG-RTC method merely solves the E-field in the whole computational region, while the H-field is only present at the interfaces of adjacent subdomains, which thus significantly reduces the number of unknowns. Moreover, the finalized globally coupled matrix equation is split into …


Satellite Drag Coefficient Modeling For Thermosphere Science And Mission Operations, Piyush M. Mehta, Smriti N. Paul, Nicholas H. Crisp, Philip L. Sheridan, Christian Siemes, Günther March, Sean Bruinsma Jan 2022

Satellite Drag Coefficient Modeling For Thermosphere Science And Mission Operations, Piyush M. Mehta, Smriti N. Paul, Nicholas H. Crisp, Philip L. Sheridan, Christian Siemes, Günther March, Sean Bruinsma

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Satellite drag modeling remains the largest source of uncertainty affecting space operations in low Earth orbit. The uncertainty stems from inaccurate models for mass density and drag coefficient. Drag coefficient modeling also impacts scientific knowledge on the physics and dynamics of the upper atmosphere through the estimation of high-fidelity mass density from measurements of acceleration on-board satellites. Efforts over the last decade have pushed drag coefficient modeling in the right direction, however, have resulted in multiple methods and tools. We provide a comprehensive review of the drag coefficient modeling methods and tools. Current scale differences between thermospheric data sets mostly …


Effects Of Wheel Rotation On Long-Period Wake Dynamics Of The Drivaer Fastback Model, Matthew Aultman, Rodrigo Auza-Gutierrez, Kevin Disotell, Lian Duan Jan 2022

Effects Of Wheel Rotation On Long-Period Wake Dynamics Of The Drivaer Fastback Model, Matthew Aultman, Rodrigo Auza-Gutierrez, Kevin Disotell, Lian Duan

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Lattice Boltzmann method (LBM) simulations were performed to capture the long-period dynamics within the wake of a realistic DrivAer fastback model with stationary and rotating wheels. The simulations showed that the wake developed as a low-pressure torus regardless of whether the wheels were rotating. This torus shrank in size on the base in the case of rotating wheels, leading to a reduction in the low-pressure footprint on the base, and consequently a 7% decrease in the total vehicle drag in comparison to the stationary wheels case. Furthermore, the lateral vortex shedding experienced a long-period switching associated with the bi-stability in …


Comparison Of Mechanical And Column Flotation Performances On Recovery Of Phosphate Slimes In Presence Of Nano-Microbubbles, Fatemeh Taghavi, Mohammad Noaparast, Ziaeddin Pourkarimi, Fardis Nakhaei Jan 2022

Comparison Of Mechanical And Column Flotation Performances On Recovery Of Phosphate Slimes In Presence Of Nano-Microbubbles, Fatemeh Taghavi, Mohammad Noaparast, Ziaeddin Pourkarimi, Fardis Nakhaei

Mining Engineering Faculty Research & Creative Works

Fine particle flotation has been one of the main problems in many mineral processing plants. The bubble-particle collision rate is very low for fine particles, which reduces flotation efficiency. Also, the existence of slimes is, generally, detrimental to the flotation process, affecting the selectivity and the quality of the concentrates. Besides, it causes an increase in reagents consumption. Hence, in most of processing plants, some of these particles are transmitted to the tailing ponds to reduce the effects of these problems and increase the selectivity of the process. Esfordi phosphate plant in Iran loses more than 30% of its capacity …


Dual-Band Decoupling Network For Mimo Antennas, Min Li, Lijun Jiang, Kwan Lawrence Yeung Jan 2022

Dual-Band Decoupling Network For Mimo Antennas, Min Li, Lijun Jiang, Kwan Lawrence Yeung

Electrical and Computer Engineering Faculty Research & Creative Works

This paper presents a novel method to design a decoupling network (DN) to increase isolation between dual-band antennas. The DN design is based on the scattering matrix and optimized by the Genetic Algorithm (GA). The decoupling example shows that the DN offers impedance matching and high isolation within desired bands, verifying the concept.


Guest Editorial, Ming Yu, Lijun Jiang, Alex M.H. Wong Jan 2022

Guest Editorial, Ming Yu, Lijun Jiang, Alex M.H. Wong

Electrical and Computer Engineering Faculty Research & Creative Works

No abstract provided.


A Fast Awe-Augmented Wideband Discontinuous Galerkin Frequency-Domain Method In Solving Electromagnetic Wave Equations, Shi Min Liu, Li (Lijun) Jun Jiang, Ping Li Jan 2022

A Fast Awe-Augmented Wideband Discontinuous Galerkin Frequency-Domain Method In Solving Electromagnetic Wave Equations, Shi Min Liu, Li (Lijun) Jun Jiang, Ping Li

Electrical and Computer Engineering Faculty Research & Creative Works

In this research, a discontinuous Galerkin frequency-domain (DGFD) method is proposed to solve the electromagnetic wave equations. Different to the explicit time-domain analysis, the electric-field and magnetic-field in frequency-domain wave equations are coupled together implicitly, thus the established matrix equation is globally coupled, which is computational expensive if solving it directly. To address this issue, a Block-diagonal preconditioner and a restriction operator are applied to the matrix equation, which splits the global matrix into a number of small local matrix systems pertinent to each subdomain. Then, a direct solver can be employed to solve them with a FETI-like procedure. Besides, …


Modeling Radiated Emissions From Pcbs In Shielding Enclosures Based On A Numerical Green's Function Approach, Zi An Wang, Li (Lijun) Jun Jiang, Jun Fa Mao, Ping Li Jan 2022

Modeling Radiated Emissions From Pcbs In Shielding Enclosures Based On A Numerical Green's Function Approach, Zi An Wang, Li (Lijun) Jun Jiang, Jun Fa Mao, Ping Li

Electrical and Computer Engineering Faculty Research & Creative Works

To accurately and efficiently model the radiated emissions from printed circuit boards (PCBs) placed in shielding enclosures, in this work, a novel approach based on the numerical Green's function (NGF) is proposed. In terms of Schelkunoff's equivalence principle, if the interior of the shielding enclosure is filled up with perfectly electric conductor (PEC), only tangential electric fields over the ventilation slots are sufficient to obtain the radiated emissions. However, due to the presence of the PEC filled shielding box, the in-situ Green's function is not available. To conquer this problem, the proposed approach can be split into two steps. In …


Supporting Green Neuromorphic Computing: Machine Learning Guided Microfabrication For Resistive Random Access Memory, Abdi Yamil Vicenciodelmoral, Md Mehedi Hasan Tanim, Feng Zhao, Xinghui Zhao Jan 2022

Supporting Green Neuromorphic Computing: Machine Learning Guided Microfabrication For Resistive Random Access Memory, Abdi Yamil Vicenciodelmoral, Md Mehedi Hasan Tanim, Feng Zhao, Xinghui Zhao

Electrical and Computer Engineering Faculty Research & Creative Works

The growing popularity of big data and machine learning applications call for a more powerful and energy-efficient way to execute deep learning workflows. Neuromorphic chips provide a potential solution, as they attempt to mimic the neuronal architectures in human brain and show great potentials in reducing energy consumption in the order of magnitude and also improve the computational performance. However, the fabrication process for neuromorphic chips is costly and currently based on trial-and-error, which adds complexity to the design process. In this paper, we address this challenge by designing and developing machine learning guided microfabrication process for Resistive Random Access …


Passive Intermodulation Under Different Spring Contact Conditions, Shengxuan Xia, Emmanuel Olugbade, Yuchu He, Yansheng Wang, Hanfeng Wang, Krishna Rao, Marco Poort, Haicheng Zhou, Warren Lee, Nicholas Mcdonnell, Jonghyun Park, Chulsoon Hwang Jan 2022

Passive Intermodulation Under Different Spring Contact Conditions, Shengxuan Xia, Emmanuel Olugbade, Yuchu He, Yansheng Wang, Hanfeng Wang, Krishna Rao, Marco Poort, Haicheng Zhou, Warren Lee, Nicholas Mcdonnell, Jonghyun Park, Chulsoon Hwang

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Modularized designs have been widely used in today's consumer electronic devices and flexible RF springs are used for electrical connections between the modules. In the meantime, aluminum alloy material becomes a common chassis option. It is well known that the oxidized chassis surface introduces a certain level of nonlinearity when contacted by the springs, as known as passive intermodulation (PIM). PIM is one of the well-known root causes of the RF desensitization (desense). This paper is focused on investigating the relationship between PIM and contact conditions of the springs, especially contact area. The PIM level behavior is explained mathematically by …


Fuel-Rich Hetero-/Homogeneous Combustion Of C3h8/O2/N2 Mixtures Over Rhodium, John Mantzaras, Ran Sui, Rolf Bombach Jan 2022

Fuel-Rich Hetero-/Homogeneous Combustion Of C3h8/O2/N2 Mixtures Over Rhodium, John Mantzaras, Ran Sui, Rolf Bombach

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The catalytic (heterogeneous) and gas-phase (homogeneous) combustion of C3H8/O2/N2 mixtures over rhodium was investigated experimentally and numerically at 5 bar and at fuel-rich equivalence ratios π = 2.0-3.5 relevant to propane Catalytic Partial Oxidation (CPO). In situ spatially-resolved Raman measurements of major gas-phase species concentrations and Planar Laser Induced Fluorescence (PLIF) of formaldehyde were applied in an optically accessible channel-flow reactor to monitor the catalytic and gas-phase processes, respectively, while accompanying 2D simulations were carried out with detailed hetero-/homogeneous chemical reaction mechanisms. Due to the high gas-phase reactivity of propane, homogeneous chemistry could not be ignored over most of the …


Regulation Of Dendrite-Free Li Plating Via Lithiophilic Sites On Lithium-Alloy Surface, Yufang He, Mengyun Zhang, Aiping Wang, Bo Zhang, Hiep Pham, Qiao Hu, Li Sheng, Hong Xu, Li Wang, Jonghyun Park, Xiangming He Jan 2022

Regulation Of Dendrite-Free Li Plating Via Lithiophilic Sites On Lithium-Alloy Surface, Yufang He, Mengyun Zhang, Aiping Wang, Bo Zhang, Hiep Pham, Qiao Hu, Li Sheng, Hong Xu, Li Wang, Jonghyun Park, Xiangming He

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Lithium (Li) deposition behavior plays an important role in dendrite formation and the subsequent performance of lithium metal batteries. This work reveals the impact of the lithiophilic sites of lithium-alloy on the Li plating process via the first-principles calculations. We find that the Li deposition mechanisms on the Li metal and Li22Sn5 surface are different due to the lithiophilic sites. We first propose that Li plating on the Li metal surface goes through the "adsorption-reduction-desorption-heterogeneous nucleation-cluster drop "process, while it undergoes the "adsorption-reduction-growth "process on the Li22Sn5 surface. The lower adsorption energy contributes to the easy adsorption of Li on …