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Articles 7051 - 7080 of 33628
Full-Text Articles in Entire DC Network
Model Order Reduction Schemes In Solving Multi-Scale Electromagnetic Problems, Qin S. Liu, Li (Lijun) Jun Jiang, Qi Dai, Hui Gan, Tian Xia, Ting Wan, Sheng Sun, Weng Cho Chew
Model Order Reduction Schemes In Solving Multi-Scale Electromagnetic Problems, Qin S. Liu, Li (Lijun) Jun Jiang, Qi Dai, Hui Gan, Tian Xia, Ting Wan, Sheng Sun, Weng Cho Chew
Electrical and Computer Engineering Faculty Research & Creative Works
Reduced-order models show significant advantages in solving multi-scale electromagnetic problems when the equivalence surfaces are used to enclose the dense-mesh features. With much coarse discretization on the equivalence surface, the computational complexities are largely reduced. Additionally, the scheme is suitable for the scattering problems especially when the location of radiator changes.
Noncontact Time-Domain Emi Measurement Of Two Adjacent Traces On A Pcb, Haimi Qiu, Chengyang Luo, Wenxiao Fang, Lijun Jiang
Noncontact Time-Domain Emi Measurement Of Two Adjacent Traces On A Pcb, Haimi Qiu, Chengyang Luo, Wenxiao Fang, Lijun Jiang
Electrical and Computer Engineering Faculty Research & Creative Works
Nonintrusive electromagnetic interference (EMI) detection is a powerful method for EMI diagnosis in high-speed links and multiple signal PCB designs. However, due to the dispersive nature of signal delivery passages and interferences from neighborhood signals, it is very difficult to locate exactly the EMI source of two adjacent traces without contact. In this paper, a noncontact time-domain voltage measurement method is proposed to detect the EMI signals of two adjacent traces on a PCB. A near-field electric probe is employed and a reconstruction algorithm is developed to recover the voltage signals without contact. Through experimental benchmarks, it is demonstrated that …
The Evolution Of Peec Methods For Si, Pi, And Antennas, Lijun Jiang, Albert E. Ruehli
The Evolution Of Peec Methods For Si, Pi, And Antennas, Lijun Jiang, Albert E. Ruehli
Electrical and Computer Engineering Faculty Research & Creative Works
No abstract provided.
Introduction To The Finite-Difference Time-Domain (Fdtd) Technique, Bruce Archambeault
Introduction To The Finite-Difference Time-Domain (Fdtd) Technique, Bruce Archambeault
Electrical and Computer Engineering Faculty Research & Creative Works
No abstract provided.
Soft Ferrites For Emc Applications, Marina Y. Koledintseva
Soft Ferrites For Emc Applications, Marina Y. Koledintseva
Electrical and Computer Engineering Faculty Research & Creative Works
No abstract provided.
Equivalent Capacitance And Multilayer Models For Effective Roughness Dielectric In Pcbs, Marina Koledintseva, Tracey Vincent
Equivalent Capacitance And Multilayer Models For Effective Roughness Dielectric In Pcbs, Marina Koledintseva, Tracey Vincent
Electrical and Computer Engineering Faculty Research & Creative Works
Effective Roughness Dielectric (ERD) is used to substitute copper foil roughness in printed circuit board (PCB) interconnects. In this work, the equivalent capacitance approach is used to get the ERD parameters based on the understanding that there is a gradual variation of concentration of metallic inclusions in the transition layer between the dielectric and foil. The metallic concentration profile can be extracted from scanning electron microscopy (SEM) or high-resolution optical microscopy. The proposed model of equivalent capacitance with gradient dielectric is applied to standard (STD), very-low-profile (VLP), and hyper-very-low profile (HVLP) foils, and the frequency-dependent dielectric parameters of the homogenized …
Influence Of Higher-Order Modes In Coaxial Waveguide On Measurements Of Material Parameters, Dmitry A. Petrov, Konstantin N. Rozanov, Marina Y. Koledintseva
Influence Of Higher-Order Modes In Coaxial Waveguide On Measurements Of Material Parameters, Dmitry A. Petrov, Konstantin N. Rozanov, Marina Y. Koledintseva
Electrical and Computer Engineering Faculty Research & Creative Works
The use of a coaxial air-filled line as a test fixture for measuring complex permittivity and permeability often shows odd resonance-like behavior of material parameters as functions of frequency. This effect is typically either ascribed to the half-wavelength resonance at the sample length, or erroneously misinterpreted as intrinsic resonance behavior of the material. However, as is shown in this paper, such behavior can be attributed to excitation of the higher-order modes on the surface of the sample resulting in resonance absorption of electromagnetic energy in the test fixture. Herein, analytical, numerical, and experimental results show that there can actually be …
Introduction To The (Peec) Partial Element Equivalent Circuit Approach Applied To Si/Pi, Albert E. Ruehli, Lijun Jiang, Giulio Antonini
Introduction To The (Peec) Partial Element Equivalent Circuit Approach Applied To Si/Pi, Albert E. Ruehli, Lijun Jiang, Giulio Antonini
Electrical and Computer Engineering Faculty Research & Creative Works
This article consists only of a collection of slides from the author's conference presentation.
Close Examination Of The Ground-State Casimir-Polder Interaction: Time-Ordered Versus Covariant Formalism And Radiative Corrections, C. M. Adhikari, Ulrich D. Jentschura
Close Examination Of The Ground-State Casimir-Polder Interaction: Time-Ordered Versus Covariant Formalism And Radiative Corrections, C. M. Adhikari, Ulrich D. Jentschura
Physics Faculty Research & Creative Works
The purpose of this paper is twofold. First, we compare, in detail, the derivation of the Casimir-Polder interaction using time-ordered perturbation theory, to the matching of the scattering amplitude using quantum electrodynamics. In the first case, a total of twelve time-ordered diagrams need to be considered, while in the second case, one encounters only two Feynman diagrams, namely, the ladder and crossed-ladder contributions. For ground-state interactions, we match the contribution of six of the time-ordered diagrams against the corresponding Feynman diagrams, showing the consistency of the two approaches. Second, we also examine the leading radiative correction to the long-range interaction, …
Anharmonic Phonon Coupling In Single-Crystal Semiconducting And Metal-Like Van Der Waals In2se3, John Igo, Shengwen Zhou, Zhi Gang Yu, Oliver Peter Amnuayphol, Feng Zhao, Yi Gu
Anharmonic Phonon Coupling In Single-Crystal Semiconducting And Metal-Like Van Der Waals In2se3, John Igo, Shengwen Zhou, Zhi Gang Yu, Oliver Peter Amnuayphol, Feng Zhao, Yi Gu
Electrical and Computer Engineering Faculty Research & Creative Works
We study the anharmonic phonon interactions in the single-crystal semiconducting (α) and metal-like (β) van der Waals In2Se3 layers, through the determination and analysis of temperature-dependent Raman spectra and thermal conductivities, supported by first-principles calculations of phonon band structures. Our results indicate strong lattice anharmonicity in β-In2Se3 giving rise to significant phonon peak broadening and a suppressed lattice thermal conductivity and reveal that the anharmonic phonon interactions are the main thermal transport-limiting mechanism in both phases. The low thermal conductivity combined with a large electrical conductivity makes the metal-like β-In2Se3 a potential efficient thermoelectric material.
Elm-Som: A Continuous Self-Organizing Map For Visualization, Renjie Hu, Venous Roshdibenam, Hans J. Johnson, Emil Eirola, Anton Akusok, Yoan Miche, Kaj Mikael Björk, Amaury Lendasse
Elm-Som: A Continuous Self-Organizing Map For Visualization, Renjie Hu, Venous Roshdibenam, Hans J. Johnson, Emil Eirola, Anton Akusok, Yoan Miche, Kaj Mikael Björk, Amaury Lendasse
Engineering Management and Systems Engineering Faculty Research & Creative Works
This Paper Presents a Novel Dimensionality Reduction Technique: Elm-Som. This Technique Preserves the Intrinsic Quality of Self-Organizing Maps (Som): It is Nonlinear and Suitable for Big Data. It Also Brings Continuity to the Projection using Two Extreme Learning Machine (Elm) Models, the First One to Perform the Dimensionality Reduction and the Second One to Perform the Reconstruction. Elm-Som is Tested Successfully on Six Diverse Datasets. Regarding Reconstruction Error, Elm-Som is Comparable to Som While Bringing Continuity.
Meta-Learning Related Tasks With Recurrent Networks: Optimization And Generalization, Thy Nguyen, A. Steven Younger, Emmett Redd, Tayo Obafemi-Ajayi
Meta-Learning Related Tasks With Recurrent Networks: Optimization And Generalization, Thy Nguyen, A. Steven Younger, Emmett Redd, Tayo Obafemi-Ajayi
Electrical and Computer Engineering Faculty Research & Creative Works
There have been recent interest in meta-learning systems: I.e., networks that are trained to learn across multiple tasks. This paper focuses on optimization and generalization of a meta-learning system based on recurrent networks. The optimization investigates the influence of diverse structures and parameters on its performance. We demonstrate the generalization (robustness) of our meta-learning system to learn across multiple tasks including tasks unseen during the meta training phase. We introduce a meta-cost function (Mean Squared Fair Error) that enhances the performance of the system by not penalizing it during transitions to learning a new task. Evaluation results are presented for …
Off-Policy Integral Reinforcement Learning For Semi-Global Constrained Output Regulation Of Continuous-Time Linear Systems, Yongliang Yang, Xianzhong Chen, Yixin Yin, Donald C. Wunsch
Off-Policy Integral Reinforcement Learning For Semi-Global Constrained Output Regulation Of Continuous-Time Linear Systems, Yongliang Yang, Xianzhong Chen, Yixin Yin, Donald C. Wunsch
Electrical and Computer Engineering Faculty Research & Creative Works
This paper presents a data-driven method based on off-policy integral reinforcement learning to solve the semi-global output regulation of continuous-time linear systems with input saturation. A family of state feedback laws for the input constrained output regulation problem is designed based on solving an algebraic Riccati equation. In contrast to the existing methods, complete knowledge of the system dynamics is no longer required in this paper. Instead, the data collected from online implementation is efficiently utilized to design the controller. Therefore, the controller design in this paper is data driven. It is shown that the presented method can find feedback …
Load Bearing Clip Angle Design -- Phase Ii, Cheng Yu, Zhishan Yan, Wenying Zhang, Lanping Qian
Load Bearing Clip Angle Design -- Phase Ii, Cheng Yu, Zhishan Yan, Wenying Zhang, Lanping Qian
American Iron and Steel Institute (AISI) Specifications, Standards, Manuals and Research Reports (1946 - present)
The report presents the second phase of a research project aimed at developing design methods for three limit states of CFS clip angles: shear, compression, and pull-over of the screw connections. In the Phase II work, the research focus was on investigating (1) the fastener pattern effects on the behavior and strength of clip angles; (2) the serviceability of clip angles subjected to tension; (3) the strength and behavior of clip angles subjected to combined shear and bending. Based on the research findings, revision to the Phase I method was proposed to account for the impact of the fastener spacing. …
Complete Genome Sequence Of Salinisphaera Sp. Strain Lb1, A Moderately Halo-Acidophilic Bacterium Isolated From Lake Brown, Western Australia, Kaela B. O'Dell, E. Anne Hatmaker, Adam M. Guss, Melanie R. Mormile
Complete Genome Sequence Of Salinisphaera Sp. Strain Lb1, A Moderately Halo-Acidophilic Bacterium Isolated From Lake Brown, Western Australia, Kaela B. O'Dell, E. Anne Hatmaker, Adam M. Guss, Melanie R. Mormile
Biological Sciences Faculty Research & Creative Works
Salinisphaera sp. strain LB1 was isolated from Lake Brown, Western Australia, surface water enriched at pH 4.0 and with 5% (wt/vol) NaCl. The complete genome sequence is presented in this report.
Modeling And An Immersed Finite Element Method For An Interface Wave Equation, Jinwei Bai, Yong Cao, Xiaoming He, Hongyan Liu, Xiaofeng Yang
Modeling And An Immersed Finite Element Method For An Interface Wave Equation, Jinwei Bai, Yong Cao, Xiaoming He, Hongyan Liu, Xiaofeng Yang
Mathematics and Statistics Faculty Research & Creative Works
The electromagnetic field, which is governed by Maxwell's equation, plays a key role in plasma simulation. In this article, we first derive the interface conditions when we rewrite the interface Maxwell's equation, whose problem domain involves complex media such as objects of different materials, into a parabolic–hyperbolic type of interface model, which is a modified wave equation by adding a first order time derivative term due to the lossy medium. Based on the interface conditions and the existing bilinear immersed finite element space for the interface Poisson equation, we propose an immersed finite element method for the spatial discretization of …
Radiation Detector Deadtime And Pile Up: A Review Of The Status Of Science, Shoaib Usman, Amol Patil
Radiation Detector Deadtime And Pile Up: A Review Of The Status Of Science, Shoaib Usman, Amol Patil
Nuclear Engineering and Radiation Science Faculty Research & Creative Works
Since the early forties, researchers from around the world have been studying the phenomenon of deadtime in radiation detectors. Many have attempted to develop models to represent this phenomenon. Two highly idealized models; paralyzable and non-paralyzable are commonly used by most individuals involved in radiation measurements. Most put little thought about the operating conditions and applicability of these ideal models for their experimental conditions. So far, there is no general agreement on the applicability of any given model for a specific detector under specific operating conditions, let alone a universal model for all detectors and all operating conditions. Further the …
Common Ground Newsletter Fall 2018, Missouri University Of Science And Technology
Common Ground Newsletter Fall 2018, Missouri University Of Science And Technology
Common Ground
-Greenberg Scholars Program
-Bayless Fellowship Fund
Low-Profile Diplexing Filter/Antenna Based On Common Radiating Cavity With Quasi-Elliptic Response, Kirti Dhwaj, Xiaoqiang Li, Li (Lijun) Jun Jiang, Tatsuo Itoh
Low-Profile Diplexing Filter/Antenna Based On Common Radiating Cavity With Quasi-Elliptic Response, Kirti Dhwaj, Xiaoqiang Li, Li (Lijun) Jun Jiang, Tatsuo Itoh
Electrical and Computer Engineering Faculty Research & Creative Works
A low-profile single-layer substrate integrated waveguide (SIW) diplexing filtering antenna with two-pole response in each channel is presented. Synthesis technique is proposed, which allows independent design of the filtering networks for the two channels. A common slot loaded SIW cavity is used to obtain the desired radiation in both channels. The diplexing filtering antenna provides quasi-elliptic response in both channels due to source-load coupling. The filtering antenna provides a maximum broadside gain of 2.65 and 2.7 dBi at operating frequencies of 5.25 (lower channel) and 5.8 GHz (upper channel), respectively. The interchannel isolation is more than 29 dB with a …
Study Of Cost Overrun And Delays Of Department Of Defense (Dod)'S Space Acquisition Program, Nazareen Sikkandar Basha, Benjamin J. Kwasa, Christina Bloebaum
Study Of Cost Overrun And Delays Of Department Of Defense (Dod)'S Space Acquisition Program, Nazareen Sikkandar Basha, Benjamin J. Kwasa, Christina Bloebaum
Engineering Management and Systems Engineering Faculty Research & Creative Works
Defense and Aerospace Systems Acquisition projects, just like any other Large-Scale Complex Engineered Systems (LSCES) experience delays and cost overrun during the acquisition process. Cost overrun and delays in LSCES are due, in part, to high complexity, size of the project, involvement of various stakeholders, organizations, political disruptions, changes in requirements and scope. These uncertainties, due to the exogenous factors, have cost the federal government billions of dollars and delays in completion of the programs. Cost estimation of federal programs is usually based on previous generations of systems produced and almost all the time the costs are underestimated. Underestimation of …
Rare Earth Elements Removal Techniques From Water/Wastewater: A Review, Omoniyi Pereao, Chris Bode-Aluko, Olanrewaju Fatoba, Katri Laatikainen, Leslie Petrik
Rare Earth Elements Removal Techniques From Water/Wastewater: A Review, Omoniyi Pereao, Chris Bode-Aluko, Olanrewaju Fatoba, Katri Laatikainen, Leslie Petrik
Mining Engineering Faculty Research & Creative Works
The rare-earth elements (REEs) remain very important due to the growing increase in their demand and for their critical and indispensable use in many high-tech industries today. This growing demand for REEs has led to an increased environmental exposure and water pollution from numerous REEs commercial products and as a result, the recovery of REEs is a significant issue that requires appropriate consideration. There are diverse and various strategic techniques available to remove metal ions from aqueous solutions, but nanofiber adsorbent appears to be quite innovative due to their outstanding characteristics such as cost effectiveness, flexibility, high surface area, porosity, …
Real-Time Observation Of Molecular Spinning With Angular High-Harmonic Spectroscopy, Lixin He, Pengfei Lan, Anh-Thu Le, Baoning Wang, Bincheng Wang, Xiaosong Zhu, Peixiang Lu, C. D. Lin
Real-Time Observation Of Molecular Spinning With Angular High-Harmonic Spectroscopy, Lixin He, Pengfei Lan, Anh-Thu Le, Baoning Wang, Bincheng Wang, Xiaosong Zhu, Peixiang Lu, C. D. Lin
Physics Faculty Research & Creative Works
We demonstrate an angular high-harmonic spectroscopy method to probe the spinning dynamics of a molecular rotation wave packet in real time. With the excitation of two time-delayed, polarization-skewed pump pulses, the molecular ensemble is impulsively kicked to rotate unidirectionally, which is subsequently irradiated by another delayed probe pulse for high-order harmonic generation (HHG). The spatiotemporal evolution of the molecular rotation wave packet is visualized from the time-dependent angular distributions of the HHG yields and frequency shift measured at various polarization directions and time delays of the probe pulse. The observed frequency shift in HHG is demonstrated to arise from the …
An Efficient Mode-Based Domain Decomposition Hybrid 2-D/Q-2d Finite-Element Time-Domain Method For Power/Ground Plate-Pair Analysis, Ping Li, Li (Lijun) Jun Jiang, Yao Jiang Zhang, Shuai Xu, Hakan Bagci
An Efficient Mode-Based Domain Decomposition Hybrid 2-D/Q-2d Finite-Element Time-Domain Method For Power/Ground Plate-Pair Analysis, Ping Li, Li (Lijun) Jun Jiang, Yao Jiang Zhang, Shuai Xu, Hakan Bagci
Electrical and Computer Engineering Faculty Research & Creative Works
Generally, with a surface magnetic current excitation, only the TM zmn modes are activated between the power/ground plate pair. As a result, the magnetic field only has azimuthal component while the longitude component is zero. To make full use of this quasi-2-D (Q-2D) property, a Q-2D finite-element time-domain (FETD) method combined with the basic 3-D triangular prism mesh elements is firstly proposed to solve the magnetic field wave equation. It is further noted that the higher order modes are confined in the proximity of the antipads (labeled as via domain) due to the exponential attenuation property along the propagating direction. …
Circuitry Design And Magnetic Susceptibility Evaluation Of 7t Fmri Implantable Rf Coil, Rong Wang, Celia M. Dong, Ed X. Wu, Robert C. Roberts, Li (Lijun) Jun Jiang
Circuitry Design And Magnetic Susceptibility Evaluation Of 7t Fmri Implantable Rf Coil, Rong Wang, Celia M. Dong, Ed X. Wu, Robert C. Roberts, Li (Lijun) Jun Jiang
Electrical and Computer Engineering Faculty Research & Creative Works
Implantable coils have been widely utilized in functional magnetic resonance imaging (fMRI) owing to their superior signal to noise ratio. To effectively minimize the magnetic field distortion and image artifacts, the magnetic susceptibility of the implantable coil needs to be evaluated before practical use. In this work, we experimentally identify the magnetic susceptibility of each component of the implantable coil with the 7T Bruker NMR imaging scanner and provide useful guidelines for the following manufacturing. A 5 5 mm 2 implantable surface coil with a tunable frequency range is subsequently introduced for the 7T fMRI of the rat primary somatosensory …
The Rotational Spectrum And Potential Energy Surface Of The Ar-Sio Complex, Michael C. Mccarthy, Steve Alexandre Ndengue, Richard Dawes
The Rotational Spectrum And Potential Energy Surface Of The Ar-Sio Complex, Michael C. Mccarthy, Steve Alexandre Ndengue, Richard Dawes
Chemistry Faculty Research & Creative Works
The rotational spectra of five isotopic species of the Ar-SiO complex have been observed at high-spectral resolution between 8 and 18 GHz using chirped Fourier transform microwave spectroscopy and a discharge nozzle source; follow-up cavity measurements have extended these measurements to as high as 35 GHz. The spectrum of the normal species is dominated by an intense progression of a-type rotational transitions arising from increasing quanta in the Si-O stretch, in which lines up to v = 12 (~14 500 cm-1) were identified. A structural determination by isotopic substitution and a hyperfine analysis of the Ar-Si17O …
Effects Of Nearwall Modeling In The Improved-Delayed-Detached-Eddy-Simulation (Iddes) Methodology, Rohit Saini, Nader Karimi, Lian Duan, Amsini Sadiki, Amirfarhang Mehdizadeh
Effects Of Nearwall Modeling In The Improved-Delayed-Detached-Eddy-Simulation (Iddes) Methodology, Rohit Saini, Nader Karimi, Lian Duan, Amsini Sadiki, Amirfarhang Mehdizadeh
Mechanical and Aerospace Engineering Faculty Research & Creative Works
The present study aims to assess the effects of two different underlying RANS models on overall behavior of the IDDES methodology when applied to different flow configurations ranging from fully attached (plane channel flow) to separated flows (periodic hill flow). This includes investigating prediction accuracy of first and second order statistics, response to grid refinement, grey area dynamics and triggering mechanism. Further, several criteria have been investigated to assess reliability and quality of the methodology when operating in scale resolving mode. It turns out that irrespective of the near wall modeling strategy, the IDDES methodology does not satisfy all criteria …
Impulsive Dynamics And Control Of The Inertia-Wheel Pendulum, Nilay Kant, Ranjan Mukherjee
Impulsive Dynamics And Control Of The Inertia-Wheel Pendulum, Nilay Kant, Ranjan Mukherjee
Mechanical and Aerospace Engineering Faculty Research & Creative Works
The dynamics of the inertia-wheel pendulum, when subjected to impulsive inputs, can be described by algebraic equations. Optimal sequences of these inputs, that minimize their infinity norm, are designed for rest-to-rest maneuvers. The results are applied to the well-studied swing-up problem, and high-gain feedback is used for continuous approximation of the inputs and simulation of the impulsive dynamics. Analytical and simulation results establish a direct link between high wheel velocities during swing-up and control strategies that take the pendulum directly to the upright configuration. They also indicate that optimal trajectories resemble those of energy-based controllers and can be designed to …
A High-Entropy Alloy With Hierarchical Nanoprecipitates And Ultrahigh Strength, Zhiqiang Fu, Lin Jiang, Haiming Wen, For Full List Of Authors, See Publisher's Website.
A High-Entropy Alloy With Hierarchical Nanoprecipitates And Ultrahigh Strength, Zhiqiang Fu, Lin Jiang, Haiming Wen, For Full List Of Authors, See Publisher's Website.
Materials Science and Engineering Faculty Research & Creative Works
High-entropy alloys (HEAs) are a class of metallic materials that have revolutionized alloy design. They are known for their high compressive strengths, often greater than 1 GPa; however, the tensile strengths of most reported HEAs are limited. Here, we report a strategy for the design and fabrication of HEAs that can achieve ultrahigh tensile strengths. The proposed strategy involves the introduction of a high density of hierarchical intragranular nanoprecipitates. To establish the validity of this strategy, we designed and fabricated a bulk Fe25Co25Ni25Al10Ti115 HEA to consist of a principal face-centered cubic …
Explosive Dust Test Vessel Comparison Using Pulverized Pittsburgh Coal, Jacob Miller, Jay Schafler, Phillip R. Mulligan, Robert Eades, Kyle A. Perry, Catherine E. Johnson
Explosive Dust Test Vessel Comparison Using Pulverized Pittsburgh Coal, Jacob Miller, Jay Schafler, Phillip R. Mulligan, Robert Eades, Kyle A. Perry, Catherine E. Johnson
Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works
Explosions of coal dust are a major safety concern within the coal mining industry. The explosion and subsequent fires caused by coal dust can result in significant property damage, loss of life in underground coal mines and damage to coal processing facilities. The United States Bureau of Mines conducted research on coal dust explosions until 1996 when it was dissolved. In the following years, the American Society for Testing and Materials (ASTM) developed a test standard, ASTM E1226, to provide a standard test method characterizing the “explosibility” of particulate solids of combustible materials suspended in air. The research presented herein …
Revealing Particle-Scale Powder Spreading Dynamics In Powder-Bed-Based Additive Manufacturing Process By High-Speed X-Ray Imaging, Luis I. Escano, Niranjan D. Parab, Lianghua Xiong, Qilin Guo, Cang Zhao, Kamel Fezzaa, Wes Everhart, Tao Sun, Lianyi Chen
Revealing Particle-Scale Powder Spreading Dynamics In Powder-Bed-Based Additive Manufacturing Process By High-Speed X-Ray Imaging, Luis I. Escano, Niranjan D. Parab, Lianghua Xiong, Qilin Guo, Cang Zhao, Kamel Fezzaa, Wes Everhart, Tao Sun, Lianyi Chen
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Powder spreading is a key step in the powder-bed-based additive manufacturing process, which determines the quality of the powder bed and, consequently, affects the quality of the manufactured part. However, powder spreading behavior under additive manufacturing condition is still not clear, largely because of the lack of particle-scale experimental study. Here, we studied particle-scale powder dynamics during the powder spreading process by using in-situ high-speed high-energy x-ray imaging. Evolution of the repose angle, slope surface speed, slope surface roughness, and the dynamics of powder clusters at the powder front were revealed and quantified. Interactions of the individual metal powders, with …