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Faculty Publications

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Full-Text Articles in Engineering

Athena: A Unique Radiation Environment Platform At The National Ignition Facility, Nicholas J. Quartemont, George Peterson, Colton Moran, Adib J. Samin, Buguo Wang, Charles Yeamans, Brandon Woodworth, Darren Holland, James C. Petrosky, James E. Bevins Nov 2021

Athena: A Unique Radiation Environment Platform At The National Ignition Facility, Nicholas J. Quartemont, George Peterson, Colton Moran, Adib J. Samin, Buguo Wang, Charles Yeamans, Brandon Woodworth, Darren Holland, James C. Petrosky, James E. Bevins

Faculty Publications

This paper describes the ATHENA platform, an energy tuning assembly, which was developed to spectrally shape the National Ignition Facility (NIF) deuterium–tritium fusion neutron source to a thermonuclear (fusion) plus prompt fission neutron spectrum with a capability to act as a short-pulse neutron source. This unique, otherwise inaccessible radiation environment complements existing experimental facilities and capabilities. The flexible ATHENA irradiation positions were modeled using an ensemble of Monte Carlo simulations with stochastic sampling of the nuclear cross-sections to characterize the radiation environments and uncertainty for the platform. Validation of the internal neutron spectrum produced from fielding ATHENA at NIF occurred …

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Estimating Bounds Of Aerodynamic, Mass And Auxiliary Load Impacts On Autonomous Vehicles: A Powertrain Simulation Approach, Yuche Chen, Ruixiao Sun, Xuanke Wu Nov 2021

Estimating Bounds Of Aerodynamic, Mass And Auxiliary Load Impacts On Autonomous Vehicles: A Powertrain Simulation Approach, Yuche Chen, Ruixiao Sun, Xuanke Wu

Faculty Publications

Vehicle automation requires new onboard sensors, communication equipment, and/or data processing units, and may encourage modifications to existing onboard components (such as the steering wheel). These changes impact the vehicle’s mass, auxiliary load, coefficient of drag, and frontal area, which then change vehicle performance. This paper uses the powertrain simulation model FASTSim to quantify the impact of autonomy-related design changes on a vehicle’s fuel consumption. Levels 0, 2, and 5 autonomous vehicles are modeled for two battery-electric vehicles (2017 Chevrolet Bolt and 2017 Nissan Leaf) and a gasoline powered vehicle (2017 Toyota Corolla). Additionally, a level 5 vehicle is divided …

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Estimating Bounds Of Aerodynamic, Mass, And Auxiliary Load Impacts On Autonomous Vehicles: A Powertrain Simulation Approach, Yuche Chen, Ruixiao Sun, Xuanke Wu Nov 2021

Estimating Bounds Of Aerodynamic, Mass, And Auxiliary Load Impacts On Autonomous Vehicles: A Powertrain Simulation Approach, Yuche Chen, Ruixiao Sun, Xuanke Wu

Faculty Publications

Vehicle automation requires new onboard sensors, communication equipment, and/or data processing units, and may encourage modifications to existing onboard components (such as the steering wheel). These changes impact the vehicle’s mass, auxiliary load, coefficient of drag, and frontal area, which then change vehicle performance. This paper uses the powertrain simulation model FASTSim to quantify the impact of autonomy-related design changes on a vehicle’s fuel consumption. Levels 0, 2, and 5 autonomous vehicles are modeled for two battery-electric vehicles (2017 Chevrolet Bolt and 2017 Nissan Leaf) and a gasoline powered vehicle (2017 Toyota Corolla). Additionally, a level 5 vehicle is divided …

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An Efficient Track-Scale Model For Laser Powder Bed Fusion Additive Manufacturing: Part 1- Thermal Model, Reza Tangestani, Trevor Sabiston, Apratim Chsktsborty, Waqas Muhammad, Lang Yuan, Étienne Martin Nov 2021

An Efficient Track-Scale Model For Laser Powder Bed Fusion Additive Manufacturing: Part 1- Thermal Model, Reza Tangestani, Trevor Sabiston, Apratim Chsktsborty, Waqas Muhammad, Lang Yuan, Étienne Martin

Faculty Publications

This is the first of two manuscripts that presents a computationally efficient full field deterministic model for laser powder bed fusion (LPBF). A new Hybrid Line (HL) heat input model integrates an exponentially decaying (ED) heat input over a portion of a laser path to significantly reduce the computational time. Experimentally measured properties of the high gamma prime nickel-based superalloy RENÉ 65 are implemented in the model to predict the in-process temperature distribution, stresses, and distortions. The model accounts for specific properties of the material as different phases. The first manuscript presents the HL heat transfer model, which is compared …

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Optically Active Selenium Vacancies In Baga4Se7 Crystals, Brian C. Holloway, Timothy D. Gustafson, Christopher A. Lenyk, Nancy C. Giles, Kevin T. Zawilski, Peter G. Schunemann, Kent L. Averett, Larry E. Halliburton Nov 2021

Optically Active Selenium Vacancies In Baga4Se7 Crystals, Brian C. Holloway, Timothy D. Gustafson, Christopher A. Lenyk, Nancy C. Giles, Kevin T. Zawilski, Peter G. Schunemann, Kent L. Averett, Larry E. Halliburton

Faculty Publications

Barium gallium selenide (BaGa4Se7) is a recently developed nonlinear optical material with a transmission window extending from 470 nm to 17 μm. A primary application of these crystals is the production of tunable mid-infrared laser beams via optical parametric oscillation. Unintentional point defects, such as selenium vacancies, cation vacancies (barium and/or gallium), and trace amounts of transition-metal ions, are present in BaGa4Se7 crystals and may adversely affect device performance. Electron paramagnetic resonance (EPR) and optical absorption are used to identify and characterize these defects. Five distinct EPR spectra, each representing an electron …

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An Efficient Track-Scale Model For Laser Powder Bed Fusion Additive Manufacturing: Part 2-Mechanical Model, Reza Tangestani, Trevor Sabiston, Apratim Chakraborty, Lang Yuan, Nicholas Krutz, Étienne Martin Nov 2021

An Efficient Track-Scale Model For Laser Powder Bed Fusion Additive Manufacturing: Part 2-Mechanical Model, Reza Tangestani, Trevor Sabiston, Apratim Chakraborty, Lang Yuan, Nicholas Krutz, Étienne Martin

Faculty Publications

This is the second of two manuscripts that presents a computationally efficient full-field deterministic model for laser powder bed fusion (LPBF). The Hybrid Line (HL) thermal model developed in part I is extended to predict the in-process residual stresses due to laser processing of a nickel-based superalloy, RENÉ 65. The computational efficiency and accuracy of the HL thermo-mechanical model is first compared to the exponential decaying heat input model on a single-track simulation. LPBF thin-wall builds with three different laser powers and four printing patterns are evaluated in this study and compared with part-scale simulations. The simulations show good agreements …

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Meshfree Simulation And Experimental Validation Of Extreme Thermomechanical Conditions In Friction Stir Extrusion, Lei Li, Varun Gupta, Xiao Li, Anthony P. Reynolds, Glenn Grant, Ayoub Soulami Nov 2021

Meshfree Simulation And Experimental Validation Of Extreme Thermomechanical Conditions In Friction Stir Extrusion, Lei Li, Varun Gupta, Xiao Li, Anthony P. Reynolds, Glenn Grant, Ayoub Soulami

Faculty Publications

Friction stir extrusion (FSE) is a novel solid-phase processing technique that consolidates and extrudes metal powders, flakes, chips, or billets into high-performance parts by plastic deformation, which has the potential to save substantial processing time and energy. Currently, most studies on FSE are experimental and only a few numerical models have been developed to explain and predict the complex physics of the process. In this work, a meshfree simulation framework based on smoothed particle hydrodynamics (SPH) was developed for FSE. Unlike traditional grid-based methods, SPH is a Lagrangian particle-based method that can handle severe material deformations, capture moving interfaces and …

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Evaluation Of Orthogonal Strain Components In Friction Extrusion, X Li, Md. Reza-E Rabby, M Ryan, G. Grant, Anthony P. Reynolds Nov 2021

Evaluation Of Orthogonal Strain Components In Friction Extrusion, X Li, Md. Reza-E Rabby, M Ryan, G. Grant, Anthony P. Reynolds

Faculty Publications

Friction extrusion is a thermomechanical process that combines conventional extrusion with the action of a rotating die. The plastic deformation of the material being sheared and extruded is the primary source of process heat and it produces strain distributions unlike those resulting from conventional extrusion. This paper proposes an improved strain analysis that evaluates three main strain components in a series of rate-controlled friction extrusions in which the steady state was achieved. Cylindrical AA1100 extrusion billets with two embedded markers were extruded to wire with a 10:1 diametral reduction. The shape change of the embedded markers was determined via serial, …

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Traffic Collision Avoidance System: False Injection Viability, John Hannah, Robert F. Mills, Richard Dill, Douglas D. Hodson Nov 2021

Traffic Collision Avoidance System: False Injection Viability, John Hannah, Robert F. Mills, Richard Dill, Douglas D. Hodson

Faculty Publications

Safety is a simple concept but an abstract task, specifically with aircraft. One critical safety system, the Traffic Collision Avoidance System II (TCAS), protects against mid-air collisions by predicting the course of other aircraft, determining the possibility of collision, and issuing a resolution advisory for avoidance. Previous research to identify vulnerabilities associated with TCAS’s communication processes discovered that a false injection attack presents the most comprehensive risk to veritable trust in TCAS, allowing for a mid-air collision. This research explores the viability of successfully executing a false injection attack against a target aircraft, triggering a resolution advisory. Monetary constraints precluded …

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Soft Elastomeric Capacitor For Angular Rotation Sensing In Steel Components, Han Liu, Simon Laflamme, Jian Li, Caroline Bennett, William N. Collins, Austin Downey, Paul Ziehl, Hongki Jo Oct 2021

Soft Elastomeric Capacitor For Angular Rotation Sensing In Steel Components, Han Liu, Simon Laflamme, Jian Li, Caroline Bennett, William N. Collins, Austin Downey, Paul Ziehl, Hongki Jo

Faculty Publications

The authors have previously proposed corrugated soft elastomeric capacitors (cSEC) to create ultra compliant scalable strain gauges. The cSEC technology has been successfully demonstrated in engineering and biomechanical applications for in-plane strain measurements. This study extends work on the cSEC to evaluate its performance at measuring angular rotation when installed folded at the junction of two plates. The objective is to characterize the sensor’s electromechanical behavior anticipating applications to the monitoring of welded connections in steel components. To do so, an electromechanical model that maps the cSEC signal to bending strain induced by angular rotation is derived and adjusted using …

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Regularized Heuristic Method For Activation Monitor Neutron Spectrum Unfolding, Nicholas J. Quartemont, James E. Bevins Oct 2021

Regularized Heuristic Method For Activation Monitor Neutron Spectrum Unfolding, Nicholas J. Quartemont, James E. Bevins

Faculty Publications

his paper describes an activation foil measurement based neutron flux unfolding method utilizing a heuristic optimization approach. A regularization parameter based on the differential neutron flux was introduced into the optimization cost function to remove large nonphysical oscillations in the unfolded neutron energy spectrum. The procedure was completed for two example case studies ranging from thermal energies up to 20 MeV demonstrating recovery of neutron flux energy information on radiation environments where a model was partially missing or there was a discrepancy in a reaction channel. The unfolded results provided a distribution of unfolded spectra that conformed to the activation …

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A Reduced-Order Lumped Model For Li-Ion Battery Packs During Operation, Paul T. Coman, Eric C. Darcy, Brad Strangways, Ralph E. White Oct 2021

A Reduced-Order Lumped Model For Li-Ion Battery Packs During Operation, Paul T. Coman, Eric C. Darcy, Brad Strangways, Ralph E. White

Faculty Publications

Modeling heat distribution in Li-ion battery packs can be challenging, especially if the battery pack is large and the cells are operated at high C-rates, which usually requires high-order physics-based mathematical models. Reduced and simplifying models can, however, be used at lower rates. This paper presents a fast novel reduced lumped model (RLM) that can be used to calculate the temperature increase during the high-current discharge of cylindrical Li-ion cells in a subscale of a battery pack. By reducing the PDE utilized to calculate the state of charge (SoC) to ODE's and solving them analytically, the reduced model can be …

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Parameter Estimation And Application Of Anisotropic Yield Criteria For Cylindrical Aluminum Extrusions: Theoretical Developments And Stereodic Measurements, Farzana Yasmeen, Michael A. Sutton, Xiaomin Deng, Megan Ryan, Anthony P. Reynolds Oct 2021

Parameter Estimation And Application Of Anisotropic Yield Criteria For Cylindrical Aluminum Extrusions: Theoretical Developments And Stereodic Measurements, Farzana Yasmeen, Michael A. Sutton, Xiaomin Deng, Megan Ryan, Anthony P. Reynolds

Faculty Publications

Theoretical and experimental studies are presented to characterize the anisotropic plastic response under torsion loading of two nominally identical aluminum Al6061-T6 extruded round bars. Theoretical models are developed using isotropic (Von Mises 1913) and anisotropic (Barlat 1991) yield criteria, along with isotropic strain hardening formulae, to model post-yield behavior under simple torsion loading. For the case of simple shear loading, incremental plasticity theory is used to determine the theoretical elastic, plastic, and total shear strains. A set of experiments are performed to calibrate Barlat’s 1991 yield function. Several specimens are extracted at different orientations to the longitudinal direction of each …

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Occurrence And Removal Of Engineered Nanoparticles In Drinking Water Treatment And Wastewater Treatment A Review, Cheng Yu, Sewoon Kim, Min Jang, Chang Min Park, Yeomin Yoon Oct 2021

Occurrence And Removal Of Engineered Nanoparticles In Drinking Water Treatment And Wastewater Treatment A Review, Cheng Yu, Sewoon Kim, Min Jang, Chang Min Park, Yeomin Yoon

Faculty Publications

Engineered nanoparticles (ENPs) are widely used in various industrial products and consumer goods, resulting in their widespread existence, particularly in natural water systems and water and wastewater treatment plants. Their presence in surface water for human consumption may severely harm human health. Therefore, this review examines new findings and developments in the removal technology of ENPs in drinking water and wastewater treatment processes since the publication of the literature by Park et al. [1]. By evaluating recent articles, this review investigates the occurrence of ENPs, discusses the transport of nanoparticles (NPs) in various drinking water and wastewater treatment …

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High-Order Deterministic Sensitivity Analysis And Uncertainty Quantification: Review And New Developments, Dan Gabriel Cacuci Oct 2021

High-Order Deterministic Sensitivity Analysis And Uncertainty Quantification: Review And New Developments, Dan Gabriel Cacuci

Faculty Publications

This work reviews the state-of-the-art methodologies for the deterministic sensitivity analysis of nonlinear systems and deterministic quantification of uncertainties induced in model responses by uncertainties in the model parameters. The need for computing high-order sensitivities is underscored by presenting an analytically solvable model of neutron scattering in a hydrogenous medium, for which all of the response’s relative sensitivities have the same absolute value of unity. It is shown that the wider the distribution of model parameters, the higher the order of sensitivities needed to achieve a desired level of accuracy in representing the response and in computing the response’s expectation, …

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A High-Pressure Shear Testing Approach To Measure Flow Stresses Near A Friction Stir Welding Tool, David Prymak, Michael Miles, Tracy W. Nelson, Fredrick Michael Oct 2021

A High-Pressure Shear Testing Approach To Measure Flow Stresses Near A Friction Stir Welding Tool, David Prymak, Michael Miles, Tracy W. Nelson, Fredrick Michael

Faculty Publications

A new approach for measuring flow stresses near a spinning friction stir welding (FSW) tool is evaluated on AA 6061-T6 plate. The test consists of plunging a cylindrical tool with a flat face into the plate at different rotational speeds, using a variety of constant vertical loads. A viscosity-based model of the shear layer created under the tool is employed to estimate local flow stresses. The flow stresses measured by this approach exhibited an inverse relationship with temperature and a positive dependence on the pressure imposed by the spinning flat-faced tool. Compared to hot compression and hot torsion results, estimated …

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On The Need To Determine Accurately The Impact Of Higher-Order Sensitivities On Model Sensitivity Analysis, Uncertainty Quantification And Best-Estimate Predictions, Dan Gabriel Cacuci Oct 2021

On The Need To Determine Accurately The Impact Of Higher-Order Sensitivities On Model Sensitivity Analysis, Uncertainty Quantification And Best-Estimate Predictions, Dan Gabriel Cacuci

Faculty Publications

This work aims at underscoring the need for the accurate quantification of the sensitivities (i.e., functional derivatives) of the results (a.k.a. “responses”) produced by large-scale computational models with respect to the models’ parameters, which are seldom known perfectly in practice. The large impact that can arise from sensitivities of order higher than first has been highlighted by the results of a third-order sensitivity and uncertainty analysis of an OECD/NEA reactor physics benchmark, which will be briefly reviewed in this work to underscore that neglecting the higher-order sensitivities causes substantial errors in predicting the expectation and variance of model responses. The …

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Automated Fiber Placement: A Review Of History, Current Technologies, And Future Paths Forward, Alex Brasington, Christopher Sacco, Joshua Halbritter, Roudy Wehbe, Ramy Harik Oct 2021

Automated Fiber Placement: A Review Of History, Current Technologies, And Future Paths Forward, Alex Brasington, Christopher Sacco, Joshua Halbritter, Roudy Wehbe, Ramy Harik

Faculty Publications

Automated fiber placement (AFP) is a composite manufacturing technique used to fabricate complex advanced air vehicle structures that are lightweight with superior qualities. The AFP process is intricate and complex with various phases of design, process planning, manufacturing, and inspection. An understanding of each of these phases is necessary to achieve the highest possible manufacturing quality. This literature review aims to summarize the entire AFP process from the design of the structure through inspection of the manufactured part to generate an overall understanding of the lifecycle of AFP manufacturing. The review culminates with highlighting the challenges and future directions for …

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High-Order Deterministic Sensitivity Analysis And Uncertainty Quantification: Review And New Developments, Dan Gabriel Cacuci Oct 2021

High-Order Deterministic Sensitivity Analysis And Uncertainty Quantification: Review And New Developments, Dan Gabriel Cacuci

Faculty Publications

This work reviews the state-of-the-art methodologies for the deterministic sensitivity analysis of nonlinear systems and deterministic quantification of uncertainties induced in model responses by uncertainties in the model parameters. The need for computing high-order sensitivities is underscored by presenting an analytically solvable model of neutron scattering in a hydrogenous medium, for which all of the response’s relative sensitivities have the same absolute value of unity. It is shown that the wider the distribution of model parameters, the higher the order of sensitivities needed to achieve a desired level of accuracy in representing the response and in computing the response’s expectation, …

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Performance-Based Building System Manufacturer Selection Decision Framework For Integration Into Total Cost Of Ownership Evaluations, Sarah L. Brown, Steven J. Schuldt, Michael N. Grussing, Louis B. Bartels, Michael A. Johnson, Justin D. Delorit Oct 2021

Performance-Based Building System Manufacturer Selection Decision Framework For Integration Into Total Cost Of Ownership Evaluations, Sarah L. Brown, Steven J. Schuldt, Michael N. Grussing, Louis B. Bartels, Michael A. Johnson, Justin D. Delorit

Faculty Publications

Facility managers are often faced with building system procurement or replacement decisions, requiring them to select a system from among competitive manufacturers. Total cost of ownership (TCO) criteria, informed by built assets in operation in the manager’s portfolio, provides some information to select the right asset manufacturer. However, managers must also consider technical performance to complete a more comprehensive analysis. Performance can be calculated using asset parameters like condition, age, and variation in condition to aid in TCO assessments. Leveraging past research and approaches, performance is calculated using an additive model that scales each parameter using a standard normalization technique …

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On The Need To Determine Accurately The Impact Of Higher-Order Sensitivities On Model Sensitivity Analysis, Uncertainty Quantification And Best-Estimate Predictions, Dan Gabriel Cacuci Oct 2021

On The Need To Determine Accurately The Impact Of Higher-Order Sensitivities On Model Sensitivity Analysis, Uncertainty Quantification And Best-Estimate Predictions, Dan Gabriel Cacuci

Faculty Publications

This work aims at underscoring the need for the accurate quantification of the sensitivities (i.e., functional derivatives) of the results (a.k.a. “responses”) produced by large-scale computational models with respect to the models’ parameters, which are seldom known perfectly in practice. The large impact that can arise from sensitivities of order higher than first has been highlighted by the results of a third-order sensitivity and uncertainty analysis of an OECD/NEA reactor physics benchmark, which will be briefly reviewed in this work to underscore that neglecting the higherorder sensitivities causes substantial errors in predicting the expectation and variance of model responses. The …

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Survivability Analysis In The Shadow Of Apollo: Part I - Cislunar Debris Propagation And Spacecraft Vulnerability, Nathan R. Boone, Robert A. Bettinger Oct 2021

Survivability Analysis In The Shadow Of Apollo: Part I - Cislunar Debris Propagation And Spacecraft Vulnerability, Nathan R. Boone, Robert A. Bettinger

Faculty Publications

Although the reality of routine travel and sustained operations and habitation in space likely remains several decades away, the building blocks of space exploration and space system development necessary to realize this reality are currently being laid by peer, near-peer, and emerging space-faring nations. Traditionally, global space operations were notionally limited to near-Earth space, with mission altitudes extending to geosynchronous or even highly elliptical orbits. During the 2010s, however, space operations began moving beyond this paradigm to encompass cislunar space with reinvigorated U.S. initiatives to return to the Moon via the Artemis program, planned commercial space projects, and an accelerated …

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Shifting Satellite Control Paradigms: Operational Cybersecurity In The Age Of Megaconstellations, Carl A. Poole, Robert A. Bettinger, Mark Reith Oct 2021

Shifting Satellite Control Paradigms: Operational Cybersecurity In The Age Of Megaconstellations, Carl A. Poole, Robert A. Bettinger, Mark Reith

Faculty Publications

The introduction of automated satellite control systems into a space-mission environment historically dominated by human-in-the-loop operations will require a more focused understanding of cybersecurity measures to ensure space system safety and security. On the ground-segment side of satellite control, the debut of privately owned communication antennas for rent and a move to cloud-based operations or mission centers will bring new requirements for cyber protection for both Department of Defense and commercial satellite operations alike. It is no longer a matter of whether automation will be introduced to satellite operations, but how quickly satellite operators can adapt to the onset of …

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Intelligent Optimization Algorithm-Based Path Planning For A Mobile Robot, Qisong Song, Shaobo Li, Jing Yang, Qiang Bai, Jianjun Hu, Xingxing Zhang, Ansi Zhang Sep 2021

Intelligent Optimization Algorithm-Based Path Planning For A Mobile Robot, Qisong Song, Shaobo Li, Jing Yang, Qiang Bai, Jianjun Hu, Xingxing Zhang, Ansi Zhang

Faculty Publications

The purpose of mobile robot path planning is to produce the optimal safe path. However, mobile robots have poor real-time obstacle avoidance in local path planning and longer paths in global path planning. In order to improve the accuracy of real-time obstacle avoidance prediction of local path planning, shorten the path length of global path planning, reduce the path planning time, and then obtain a better safe path, we propose a real-time obstacle avoidance decision model based on machine learning (ML) algorithms, an improved smooth rapidly exploring random tree (S-RRT) algorithm, and an improved hybrid genetic algorithm-ant colony optimization (HGA-ACO). …

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Recent Development Of Unpowered Exoskeletons For Lower Extremity: A Survey, Tao Liu, Bin Zhang, Bin Zhang, Micheal G. Pecht Sep 2021

Recent Development Of Unpowered Exoskeletons For Lower Extremity: A Survey, Tao Liu, Bin Zhang, Bin Zhang, Micheal G. Pecht

Faculty Publications

Unpowered exoskeletons (UEs) have attracted extensive research attentions for their portability, handleability and simplicity. However, designing exoskeletons without any active actuators is a great challenge because essential criteria such as performance enhancement, low impedance, and comfort must be met. This paper reviews the UEs researches from three aspects including modeling for understanding gait pattern, mechanical designs, and validation methods, which are main considerations of designing UEs. This review is based on the reported works in the past two decades and underlines some practical opportunities and challenges. Statistical data analysis and critical reviews are stated to understand human gait patterns, designing …

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Emr: A New Metric To Assess The Resilience Of Directional Mmwave Channels To Blockages, Faith Erden, Ozgur Ozdemir, Ismail Guvenc, David W. Matolak Sep 2021

Emr: A New Metric To Assess The Resilience Of Directional Mmwave Channels To Blockages, Faith Erden, Ozgur Ozdemir, Ismail Guvenc, David W. Matolak

Faculty Publications

Millimeter-wave (mmWave) communication systems require narrow beams to compensate for high path loss and to increase the communication range. If an obstacle blocks the dominant communication direction, alternative paths (directions) should be quickly identified to maintain reliable connectivity. In this paper, we introduce a new metric to quantify the Effective Multipath Richness (EMR) of a directional communication channel in the angular domain. In particular, the proposed metric takes into account the strength and spatial diversity of the resolved Multipath Components (MPCs), while also considering the beamwidth of the communication link and the blockage characteristics. The metric is defined as a …

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Towards Detection Of Sars-Cov-2 Rna In Human Saliva: A Paper-Based Cell-Free Toehold Switch Biosensor With A Visual Bioluminescent Output, J. Porter Hunt, Emily Long Zhao, Tyler J. Free, Mehran Soltani, Chandler A. Warr, Alex B. Benedict, Melissa K. Takahashi, Joel S. Griffitts, William G. Pitt, Bradley C. Bundy Sep 2021

Towards Detection Of Sars-Cov-2 Rna In Human Saliva: A Paper-Based Cell-Free Toehold Switch Biosensor With A Visual Bioluminescent Output, J. Porter Hunt, Emily Long Zhao, Tyler J. Free, Mehran Soltani, Chandler A. Warr, Alex B. Benedict, Melissa K. Takahashi, Joel S. Griffitts, William G. Pitt, Bradley C. Bundy

Faculty Publications

The COVID-19 pandemic has illustrated the global demand for rapid, low-cost, widely distributable and point-of-care nucleic acid diagnostic technologies. Such technologies could help disrupt transmission, sustain economies and preserve health and lives during widespread infection. In contrast, conventional nucleic acid diagnostic procedures require trained personnel, complex laboratories, expensive equipment, and protracted processing times. In this work, lyophilized cell-free protein synthesis (CFPS) and toehold switch riboregulators are employed to develop a promising paper-based nucleic acid diagnostic platform activated simply by the addition of saliva. First, to facilitate distribution and deployment, an economical paper support matrix is identified and a mass-producible test …

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Drone-Based Vibration Monitoring And Assessment Of Structures, Sabrina Carroll, Joud Satme, Shadhan Alkharusi, Nikolaos Vitzilaios, Austin Downey, Dimitris Rizos Sep 2021

Drone-Based Vibration Monitoring And Assessment Of Structures, Sabrina Carroll, Joud Satme, Shadhan Alkharusi, Nikolaos Vitzilaios, Austin Downey, Dimitris Rizos

Faculty Publications

This paper presents a novel method of procuring and processing data for the assessment of civil structures via vibration monitoring. This includes the development of a custom sensor package designed to minimize the size/weight while being fully self-sufficient (i.e., not relying on external power). The developed package is delivered to the structure utilizing a customized Unmanned Aircraft System (UAS), otherwise known as a drone. The sensor package features an electropermanent magnet for securing it to the civil structure while a second magnet is used to secure the package to the drone during flight. The novel B-Spline Impulse Response Function (BIRF) …

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Automated Drone Detection Using Yolov4, Subroto Singha, Burchan Aydin Sep 2021

Automated Drone Detection Using Yolov4, Subroto Singha, Burchan Aydin

Faculty Publications

Drones are increasing in popularity and are reaching the public faster than ever before. Consequently, the chances of a drone being misused are multiplying. Automated drone detection is necessary to prevent unauthorized and unwanted drone interventions. In this research, we designed an automated drone detection system using YOLOv4. The model was trained using drone and bird datasets. We then evaluated the trained YOLOv4 model on the testing dataset, using mean average precision (mAP), frames per second (FPS), precision, recall, and F1-score as evaluation parameters. We next collected our own two types of drone videos, performed drone detections, and calculated the …

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Investigating Influence Of Geometry And Operating Conditions On Local Current, Concentration, And Crossover In Alkaline Water Electrolysis Using Computational Fluid Dynamics, J. S. Lopata, S-G. Kang, H-S. Cho, C-H. Kim, J. W. Weidner, Sirivatch Shimpalee Sep 2021

Investigating Influence Of Geometry And Operating Conditions On Local Current, Concentration, And Crossover In Alkaline Water Electrolysis Using Computational Fluid Dynamics, J. S. Lopata, S-G. Kang, H-S. Cho, C-H. Kim, J. W. Weidner, Sirivatch Shimpalee

Faculty Publications

We use a three-dimensional computational fluid dynamics model to examine the liquid saturation, KOH concentration, and gas crossover in an alkaline diaphragm water electrolysis device. The effects of cell potential, solution feed rate, and aspects of the design such as the locations and widths of channels on performance and crossover were studied. The results build a case for implementing a separator transport model and an electrode/separator interface model because of the concentration changes observed at the anode and cathode. Simulations suggest a strong relationship between solution feed rate and the nature of dissolved gas crossover through the diaphragm due to …

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