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Articles 5371 - 5400 of 21795

Full-Text Articles in Engineering

Identifying Corrosion Zones In Coastal Regions For Metal Pipes -- A Gis Approach, Sanjay Tewari, Francis Manning Aug 2017

Identifying Corrosion Zones In Coastal Regions For Metal Pipes -- A Gis Approach, Sanjay Tewari, Francis Manning

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Transportation agencies often allow metal pipes as an option for cross drains under/along roads and highways. Metal culverts can corrode over time at various rates based on their environmental conditions (e.g., corrosive nature of coastal soils, high water table and saltwater intrusion). This paper focuses on applying readily available soil data such as spatial distribution of soil types and soil characteristics (e.g., pH and conductivity) towards creating a geospatial information system (GIS) based approach to identifying corrosion zones in the coastal regions. A combination of data, obtained from field surveys provided by the Louisiana Transportation Research Center and Web Soil …

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Magnetic Control Of Lateral Migration Of Ellipsoidal Microparticles In Microscale Flows, R. Zhou, C. A. Sobecki, J. Zhang, Yanzhi Zhang, Cheng Wang Aug 2017

Magnetic Control Of Lateral Migration Of Ellipsoidal Microparticles In Microscale Flows, R. Zhou, C. A. Sobecki, J. Zhang, Yanzhi Zhang, Cheng Wang

Mathematics and Statistics Faculty Research & Creative Works

No abstract provided.

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Apparatus For Converting Direct Current To Alternating Current Using Multiple Converters, Patrick L. Chapman, Brian T. Kuhn, Robert S. Balog, Jonathan W. Kimball, Philip T. Krein, Alexander Gray Aug 2017

Apparatus For Converting Direct Current To Alternating Current Using Multiple Converters, Patrick L. Chapman, Brian T. Kuhn, Robert S. Balog, Jonathan W. Kimball, Philip T. Krein, Alexander Gray

Electrical and Computer Engineering Faculty Research & Creative Works

An inverter for converting an input direct current (DC) waveform from a DC source to an output alternating current (AC) waveform for delivery to an AC grid includes an input converter, an output converter, and an active filter, each of which is electrically coupled to a bus. The bus may be a DC bus or an AC bus. The input converter is configured to convert the input DC waveform to a DC or AC bus waveform. The output converter is configured to convert the bus waveform to the output AC waveform at a grid frequency. The active filter is configured …

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Klein Tunneling Near The Dirac Points In Metal-Dielectric Multilayer Metamaterials, L. Sun, Jie Gao, Xiaodong Yang Aug 2017

Klein Tunneling Near The Dirac Points In Metal-Dielectric Multilayer Metamaterials, L. Sun, Jie Gao, Xiaodong Yang

Mechanical and Aerospace Engineering Faculty Research & Creative Works

No abstract provided.

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Broadband Polarization Conversion With Anisotropic Plasmonic Metasurfaces, W. Cao, Xiaodong Yang, Jie Gao Aug 2017

Broadband Polarization Conversion With Anisotropic Plasmonic Metasurfaces, W. Cao, Xiaodong Yang, Jie Gao

Mechanical and Aerospace Engineering Faculty Research & Creative Works

No abstract provided.

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Transient Heterogeneous Electromagnetic Simulation With Dgtd And Behavioral Macromodel, Huan Huan Zhang, Li (Lijun) Jun Jiang, He Ming Yao, Yu Zhang Aug 2017

Transient Heterogeneous Electromagnetic Simulation With Dgtd And Behavioral Macromodel, Huan Huan Zhang, Li (Lijun) Jun Jiang, He Ming Yao, Yu Zhang

Electrical and Computer Engineering Faculty Research & Creative Works

A novel hybrid field-circuit simulation method is proposed for transient heterogeneous electromagnetic simulations. It adopts the discontinuous Galerkin time domain (DGTD) method and behavioral macromodel trained by artificial neural network to analyze the electromagnetic structure and circuit network, respectively. Due to the feature of DGTD method and behavioral macromodel, the proposed method can handle not only electromagnetic structures with complex geometries and materials but also manage circuits with unknown internal details. It provides a new approach that has the trainable accuracy to meet today's IP projection requestions. It is also the first time for DGTD algorithm to work with the …

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Effects Of Iron Concentration And Redox States On Failure Of Boron-Free E-Glass Fibres Under Applied Stress In Different Conditions, Qingwei Wang, Richard K. Brow, Hong Li, Erica Ann Ronchetto Aug 2017

Effects Of Iron Concentration And Redox States On Failure Of Boron-Free E-Glass Fibres Under Applied Stress In Different Conditions, Qingwei Wang, Richard K. Brow, Hong Li, Erica Ann Ronchetto

Materials Science and Engineering Faculty Research & Creative Works

Hydrolysis resistance of boron-free E-glass fiber with different total iron oxide (Fe2O3) concentrations, iron redox index and durations of fiber ageing up to 180 days at 50◦C with 50% relative humidity (RH) was studied. The effect of ageing on the fibre failure measured in two different test environments was examined by using two-point bending method. Based on the differences in failure strains of the fibres obtained from the two conditions as a function of ageing time, the Griffith theory of solid fracture was applied to estimate glass surface energy difference in ageing conditions. The results showed …

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Secure Transmission With Large Numbers Of Antennas And Finite Alphabet Inputs, Yongpeng Wu, Jun Bo Wang, Jue Wang, Robert Schober, Chengshan Xiao Aug 2017

Secure Transmission With Large Numbers Of Antennas And Finite Alphabet Inputs, Yongpeng Wu, Jun Bo Wang, Jue Wang, Robert Schober, Chengshan Xiao

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, we investigate secure transmission over the large-scale multiple-antenna wiretap channel with finite alphabet inputs. First, we investigate the case where instantaneous channel state information (CSI) of the eavesdropper is known at the transmitter. We show analytically that a generalized singular value decomposition (GSVD)-based design, which is optimal for Gaussian inputs, may exhibit a severe performance loss for finite alphabet inputs in the high signal-to-noise ratio regime. In light of this, we propose a novel Per-Group-GSVD (PG-GSVD) design, which can effectively compensate the performance loss caused by the GSVD design. More importantly, the computational complexity of the PG-GSVD …

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Structural Vs.. Compositional Disorder In Thermal Conductivity Reduction Of Sige Alloys, Jihui Nie, Raghavan Ranganathan, Zhi Liang, Pawel Keblinski Jul 2017

Structural Vs.. Compositional Disorder In Thermal Conductivity Reduction Of Sige Alloys, Jihui Nie, Raghavan Ranganathan, Zhi Liang, Pawel Keblinski

Mechanical and Aerospace Engineering Faculty Research & Creative Works

We Use Equilibrium Molecular Dynamics Simulations to Determine the Relative Role of Compositional and Structural Disorder in a Phononic Thermal Conductivity Reduction by Studying Three 50-50 SiGe Alloy Structures: Ordered Alloys, Disordered Alloys, and Amorphous Alloys, as Well as Pure Amorphous Si and Ge Structures for Reference. While Both Types of Disorders Significantly Reduce Thermal Conductivity, Structural Disorder is Much More Effective to This Aim. the Examination of Phonon Lifetimes in Disordered Alloys Shows High Values in a Low Frequency Regime Governed by Umklapp Scattering that Are Reduced Rapidly with Increasing Frequency Following Rayleigh Scattering Behavior. the Local Properties Analysis …

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Singularity Formation In The Geometry Of Perturbed Shocks Of General Mach Number, Wouter Mostert, Dale I. Pullin, Ravi Samtaney, Vincent Wheatley Jul 2017

Singularity Formation In The Geometry Of Perturbed Shocks Of General Mach Number, Wouter Mostert, Dale I. Pullin, Ravi Samtaney, Vincent Wheatley

Mechanical and Aerospace Engineering Faculty Research & Creative Works

While planar shock waves are known to be stable to small perturbations in the sense that the perturbation amplitude decays over time, it has also been suggested that plane propagating shocks can develop singularities in some derivative of their geometry (Whitham (1974) Linear and nonlinear waves. Wiley, New York) in a nonlinear, wave reinforcement process. We present a spectral-based analysis of the equations of geometrical shock dynamics that predicts the time to singularity formation in the profile of an initially perturbed planar shock for general shock Mach number. We find that following an initially sinusoidal perturbation, the shock shape remains …

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Discontinuous Galerkin Time-Domain Analysis Of Power/Ground Plate Pairs With Wave Port Excitation, Ping Li, Li (Lijun) Jun Jiang, Hakan Baǧci Jul 2017

Discontinuous Galerkin Time-Domain Analysis Of Power/Ground Plate Pairs With Wave Port Excitation, Ping Li, Li (Lijun) Jun Jiang, Hakan Baǧci

Electrical and Computer Engineering Faculty Research & Creative Works

In this work, a discontinuous Galerkin time-domain method is developed to analyze the power/ground plate pairs taking into account arbitrarily shaped antipads. To implement proper source excitations over the antipads, the magnetic surface current expanded by the electric eigen-modes supported by the corresponding antipad is employed as the excitation. For irregularly shaped antipads, the eigen-modes are obtained by numerical approach. Accordingly, the methodology for the S-parameter extraction is derived based on the orthogonal properties of the different modes. Based on the approach, the transformation between different modes can be readily evaluated.

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Numerical Modeling Of Pcb Power/Ground Plate-Pairs By Dgtd Method Taking Into Account Decoupling Capacitors, Ping Li, Li (Lijun) Jun Jiang, Hakan Baǧci Jul 2017

Numerical Modeling Of Pcb Power/Ground Plate-Pairs By Dgtd Method Taking Into Account Decoupling Capacitors, Ping Li, Li (Lijun) Jun Jiang, Hakan Baǧci

Electrical and Computer Engineering Faculty Research & Creative Works

A discontinuous Galerkin time-domain (DGTD) method is proposed in this work to analyze printed circuit board (PCB) power/ground plate-pair having arbitrarily shaped anti-pads. To apply proper excitation source over the irregular anti-pad, the implemented wave port magnetic current excitation is expanded by the electric eigen-modes of the anti-pad that are calculated via either numerical approach or analytical method. Based on the orthogonality of eigen-modes, the temporal mode expansion coefficient for each mode can be conveniently extracted. Besides, considering the presence of decoupling capacitors, the whole physical system can be split into field and circuit subsystems. For the field subsystem, it …

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Electromagnetic-Circuit Cosimulation Based On Hybrid Explicit-Implicit Dgtd And Sbf Macromodel, Ping Yuan, Huan Huan Zhang, Li (Lijun) Jun Jiang, Daniel Garcia Donoro, Yu Zhang Jul 2017

Electromagnetic-Circuit Cosimulation Based On Hybrid Explicit-Implicit Dgtd And Sbf Macromodel, Ping Yuan, Huan Huan Zhang, Li (Lijun) Jun Jiang, Daniel Garcia Donoro, Yu Zhang

Electrical and Computer Engineering Faculty Research & Creative Works

The integrated circuits usually have multiscale feature. If utilizing the explicit discontinuous Galerkin time domain (DGTD) method for electromagnetic-circuit cosimulation, the time step size will be limited to the minimum grid size according to CFL (Courant-Friedrichs-Lewy) condition, which will lead to a small time step size. In order to improve the simulation efficiency, this paper adopts the hybrid explicit-implicit DGTD coupled with the Sigmoidal basis function (SBF) macromodel to achieve electromagnetic-circuit cosimulation.

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Analytical Evaluation Of Partial Inductances With Retardation, L. Lombardi, G. Antonini, A. E. Ruehli Jul 2017

Analytical Evaluation Of Partial Inductances With Retardation, L. Lombardi, G. Antonini, A. E. Ruehli

Electrical and Computer Engineering Faculty Research & Creative Works

The Partial Element Equivalent Circuit (PEEC) circuit oriented electromagnetic method has been found particularly useful for modeling PCBs, interconnects, and 3-D problems involving both electromagnetic computations and circuits. Efficiency improvements in PEEC for higher frequencies are becoming important especially for large aspect ratio cells. The analytical solution of the six-fold integrals has been shown to lead to a very efficient solution for such integrals. In this paper we introduce a new approach for the analytical evaluation of retarded partial inductances at arbitrary distances.

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Analysis Of Time-Dependent Bearing Capacity Of A Driven Pile In Clayey Soils By Total Stress Method, Lin Li, Jingpei Li, De'an Sun, Weibing Gong Jul 2017

Analysis Of Time-Dependent Bearing Capacity Of A Driven Pile In Clayey Soils By Total Stress Method, Lin Li, Jingpei Li, De'an Sun, Weibing Gong

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

This paper proposes an analytical approach to evaluate the time-dependent bearing capacity of a driven pile in clayey soils by taking the pile installation and subsequent reconsolidation effects into consideration. The process of pile installation is modeled by undrained expansion of a spherical cavity at the pile tip and a cylindrical cavity around the pile shaft. The cavity expansion solution, which is based on a K0-consolidated anisotropic modified Cam-clay model (K0-AMCC), is used to capture the pile installation effects. After pile installation, the dissipation of the excess pore water and the increase of the effective stress in the surrounding soil …

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Solvent Based 3d Printing Of Biopolymer/Bioactive Glass Composite And Hydrogel For Tissue Engineering Applications, Krishna Kolan, Yong Liu, Jakeb Baldridge, Caroline Murphy, Julie A. Semon, D. E. Day, Ming-Chuan Leu Jul 2017

Solvent Based 3d Printing Of Biopolymer/Bioactive Glass Composite And Hydrogel For Tissue Engineering Applications, Krishna Kolan, Yong Liu, Jakeb Baldridge, Caroline Murphy, Julie A. Semon, D. E. Day, Ming-Chuan Leu

Biological Sciences Faculty Research & Creative Works

Three-dimensional (3D) bioprinting is an emerging technology in which scaffolding materials and cell-laden hydrogels may be deposited in a pre-determined fashion to create 3D porous constructs. A major challenge in 3D bioprinting is the slow degradation of melt deposited biopolymer. In this paper, we describe a new method for printing poly-caprolactone (PCL)/bioactive borate glass composite as a scaffolding material and Pluronic F127 hydrogel as a cell suspension medium. Bioactive borate glass was added to a mixture of PCL and organic solvent to make an extrudable paste using one syringe while hydrogel was extruded and deposited in between the PCL/borate glass …

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Task Assignment And Path Planning For Multiple Autonomous Underwater Vehicles Using 3d Dubins Curves, Wenyu Cai, Meiyan Zhang, Y. Rosa Zheng Jul 2017

Task Assignment And Path Planning For Multiple Autonomous Underwater Vehicles Using 3d Dubins Curves, Wenyu Cai, Meiyan Zhang, Y. Rosa Zheng

Electrical and Computer Engineering Faculty Research & Creative Works

This paper investigates the task assignment and path planning problem for multiple AUVs in three dimensional (3D) underwater wireless sensor networks where nonholonomic motion constraints of underwater AUVs in 3D space are considered. The multi-target task assignment and path planning problem is modeled by the Multiple Traveling Sales Person (MTSP) problem and the Genetic Algorithm (GA) is used to solve the MTSP problem with Euclidean distance as the cost function and the Tour Hop Balance (THB) or Tour Length Balance (TLB) constraints as the stop criterion. The resulting tour sequences are mapped to 2D Dubins curves in the X − …

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Synthesis, Characterization And Photocatalytic Activity Of Ag Metallic Particles Deposited Carbon-Doped Tio2 Nanocomposites Supported On Stainless Steel Mesh, J. O. Tijani, T. C. Totito, O. O. Fatoba, O. O. Babajide, L. F. Petrik Jul 2017

Synthesis, Characterization And Photocatalytic Activity Of Ag Metallic Particles Deposited Carbon-Doped Tio2 Nanocomposites Supported On Stainless Steel Mesh, J. O. Tijani, T. C. Totito, O. O. Fatoba, O. O. Babajide, L. F. Petrik

Mining Engineering Faculty Research & Creative Works

Abstract: In this present work, post deposition of metallic Ag nanoparticles on carbon-doped TiO2 nanocomposites supported on stainless steel mesh was achieved via a combination of sol–gel and thermal evaporation techniques. Poly acrylonitrile dissolved in dimethyl formamide, and titanium tetra chloride was used as a carbon and titanium precursor, respectively. The photocatalytic activity of the prepared supported catalysts was evaluated by the degradation of an aqueous solution of methylene blue as a model pollutant under ultra-violet light irradiation. The prepared photocatalysts were characterized by several analytical techniques such as high resolution transmission electron microscopy, energy dispersive X-ray spectroscopy, Brunauer–Emmett–Teller …

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Effect Of Wall Cooling On Boundary-Layer-Induced Pressure Fluctuations At Mach 6, C. Zhang, Lian Duan, M. Choudhari Jul 2017

Effect Of Wall Cooling On Boundary-Layer-Induced Pressure Fluctuations At Mach 6, C. Zhang, Lian Duan, M. Choudhari

Mechanical and Aerospace Engineering Faculty Research & Creative Works

No abstract provided.

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Design And Analysis Of Adaptive Control Systems Over Wireless Networks, Ali Albattat, Benjamin Gruenwald, Tansel Yucelen Jul 2017

Design And Analysis Of Adaptive Control Systems Over Wireless Networks, Ali Albattat, Benjamin Gruenwald, Tansel Yucelen

Mechanical and Aerospace Engineering Faculty Research & Creative Works

In this paper, we study the design and analysis of adaptive control systems over wireless networks using event-triggering control theory. The proposed event-triggered adaptive control methodology schedules the data exchange dependent upon errors exceeding user-defined thresholds to reduce wireless network utilization and guarantees system stability and command following performance in the presence of system uncertainties. Specifically, we analyze stability and boundedness of the overall closed-loop dynamical system, characterize the effect of user-defined thresholds and adaptive controller design parameters to the system performance, and discuss conditions to make the resulting command following performance error sufficiently small. An illustrative numerical example is …

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Novel Layered Double Hydroxides-Hydroxyapatite/Gelatin Bone Tissue Engineering Scaffolds: Fabrication, Characterization, And In Vivo Study, Fateme Fayyazbakhsh, Mehran Solati-Hashjin, Abbas Keshtkar, Mohammad Ali Shokrgozar, Mohammad Mehdi Dehghan, Bagher Larijani Jul 2017

Novel Layered Double Hydroxides-Hydroxyapatite/Gelatin Bone Tissue Engineering Scaffolds: Fabrication, Characterization, And In Vivo Study, Fateme Fayyazbakhsh, Mehran Solati-Hashjin, Abbas Keshtkar, Mohammad Ali Shokrgozar, Mohammad Mehdi Dehghan, Bagher Larijani

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Developing Porous Biodegradable Scaffolds through Simple Methods is One of the Main Approaches of Bone Tissue Engineering (BTE). in This Work, a Novel BTE Composite Containing Layered Double Hydroxides (LDH), Hydroxyapatite (HA) and Gelatin (GEL) Was Fabricated using Co-Precipitation and Solvent-Casting Methods. Physiochemical Characterizations Showed that the Chemical Composition and Microstructure of the Scaffolds Were Similar to the Natural Spongy Bone. Interconnected Macropores Ranging over 100 to 600 Μm Were Observed for Both Scaffolds While the Porosity of 90 ± 0.12% and 92.11 ± 0.15%, as Well As, Young's Modulus of 19.8 ± 0.41 and 12.5 ± 0.35 GPa Were …

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Stair Negotiation Made Easier Using Novel Interactive Energy-Recycling Assistive Stairs, Yun Seong Song, Sehoon Ha, Hsiang Hsu, Lena H. Ting, C. Karen Liu Jul 2017

Stair Negotiation Made Easier Using Novel Interactive Energy-Recycling Assistive Stairs, Yun Seong Song, Sehoon Ha, Hsiang Hsu, Lena H. Ting, C. Karen Liu

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Here we show that novel, energy-recycling stairs reduce the amount of work required for humans to both ascend and descend stairs. Our low-power, interactive, and modular steps can be placed on existing staircases, storing energy during stair descent and returning that energy to the user during stair ascent. Energy is recycled through event-triggered latching and unlatching of passive springs without the use of powered actuators. When ascending the energy-recycling stairs, naive users generated 17.4 ± 6.9% less positive work with their leading legs compared to conventional stairs, with the knee joint positive work reduced by 37.7 ± 10.5%. Users also …

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Fuzzy Color Clustering For Melanoma Diagnosis In Dermoscopy Images, Haidar A. Almubarak, R. Joe Stanley, William V. Stoecker, Randy Hays Moss Jul 2017

Fuzzy Color Clustering For Melanoma Diagnosis In Dermoscopy Images, Haidar A. Almubarak, R. Joe Stanley, William V. Stoecker, Randy Hays Moss

Electrical and Computer Engineering Faculty Research & Creative Works

A fuzzy logic-based color histogram analysis technique is presented for discriminating benign skin lesions from malignant melanomas in dermoscopy images. The approach extends previous research for utilizing a fuzzy set for skin lesion color for a specified class of skin lesions, using alpha-cut and support set cardinality for quantifying a fuzzy ratio skin lesion color feature. Skin lesion discrimination results are reported for the fuzzy clustering ratio over different regions of the lesion over a data set of 517 dermoscopy images consisting of 175 invasive melanomas and 342 benign lesions. Experimental results show that the fuzzy clustering ratio applied over …

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Effects Of Specimen Size And Yttria Concentration On Mechanical Properties Of Single Crystalline Yttria-Stabilized Tetragonal Zirconia Nanopillars, Ning Zhang, Mohsen Asle Zaeem Jul 2017

Effects Of Specimen Size And Yttria Concentration On Mechanical Properties Of Single Crystalline Yttria-Stabilized Tetragonal Zirconia Nanopillars, Ning Zhang, Mohsen Asle Zaeem

Materials Science and Engineering Faculty Research & Creative Works

The nanoscale plastic deformation of yttria-stabilized tetragonal zirconia (YSTZ) is highly dependent on the crystallographic orientations, i.e., dislocation is induced when the loading direction is 45° tilted to {111} and {101} slip planes, while tetragonal to monoclinic phase transformation dominates the plastic deformation when loading direction is perpendicular to the slip planes. This study investigates the effects of specimen size and yttria concentration on the mechanical response of single crystalline YSTZ nanopillars. Through uniaxial compression test, the smaller-is-stronger phenomenon is revealed in nanopillars deformed through a dislocation motion mechanism. Serrated stacking faults are observed in the smallest nanopillar, while neat …

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Homogenization Of Plastic Deformation In Heterogeneous Lamella Structures, Rui Yuan, Irene J. Beyerlein, Caizhi Zhou Jul 2017

Homogenization Of Plastic Deformation In Heterogeneous Lamella Structures, Rui Yuan, Irene J. Beyerlein, Caizhi Zhou

Materials Science and Engineering Faculty Research & Creative Works

It has been shown that unlike its constituent nanocrystalline (NC) phase, a heterogeneous lamella (HL) composite comprising NC and coarse-grain layers exhibits greatly improved ductility. To understand the origin of this enhancement, we present a 3D discrete dislocation, crystal plasticity finite element model to study the development of strains across this microstructure. Here we show that the HL structure homogenizes the plastic strains in the NC layer, weakening the effect of strain concentrations. These findings can provide valuable insight into the effects of material length scales on material instabilities, which is needed to design heterogeneous structures with superior properties.

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Program Progress Performance Report #1, Missouri University Of Science And Technology. Inspire - University Transportation Center Jun 2017

Program Progress Performance Report #1, Missouri University Of Science And Technology. Inspire - University Transportation Center

Semi-Annual Progress Reports

No abstract provided.

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A Low-Dimensional Vector Representation For Words Using An Extreme Learning Machine, Paula Lauren, Guangzhi Qu, Guang Bin Huang, Paul Watta, Amaury Lendasse Jun 2017

A Low-Dimensional Vector Representation For Words Using An Extreme Learning Machine, Paula Lauren, Guangzhi Qu, Guang Bin Huang, Paul Watta, Amaury Lendasse

Engineering Management and Systems Engineering Faculty Research & Creative Works

Word Embeddings Are a Low-Dimensional Vector Representation of Words that Incorporates Context. Two Popular Methods Are Word2vec and Global Vectors (Glove). Word2vec is a Single-Hidden Layer Feedforward Neural Network (Slfn) that Has an Auto-Encoder Influence for Computing a Word Context Matrix using Backpropagation for Training. Glove Computes the Word Context Matrix First Then Performs Matrix Factorization on the Matrix to Arrive at Word Embeddings. Backpropagation is a Typical Training Method for SLFN's, which is Time Consuming and Requires Iterative Tuning. Extreme Learning Machines (Elm) Have the Universal Approximation Capability of SLFN's, based on a Randomly Generated Hidden Layer Weight Matrix …

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Validation Of Adaptive Control Laws Using Optimization And Trajectory Sensitivity, Mario Luca Fravolini, Antonio Ficola, Fabio Radicioni, Tansel Yucelen, Ehsan Arabi Jun 2017

Validation Of Adaptive Control Laws Using Optimization And Trajectory Sensitivity, Mario Luca Fravolini, Antonio Ficola, Fabio Radicioni, Tansel Yucelen, Ehsan Arabi

Mechanical and Aerospace Engineering Faculty Research & Creative Works

In this paper it is proposed an easy-to-use verification and validation method for adaptive control laws that relies on time domain simulations. The problem is set as a trajectory falsification problem that is the search of closed loop trajectories that, starting from a set of admissible initial conditions, reach a set of unsafe states. The falsification is placed as a nonlinear optimization problem whose decision variables are the initial condition of the states and the uncertain parameters of the system. The falsification is performed iteratively using the local gradient of the sensitivity function derived from a linearized model of the …

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A Decentralized Adaptive Control Architecture For Large-Scale Active-Passive Modular Systems, Benjamin C. Gruenwald, Ehsan Arabi, Tansel Yucelen, Animesh Chakravarthy, Drew Mcneely Jun 2017

A Decentralized Adaptive Control Architecture For Large-Scale Active-Passive Modular Systems, Benjamin C. Gruenwald, Ehsan Arabi, Tansel Yucelen, Animesh Chakravarthy, Drew Mcneely

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Decentralized control of large-scale active-passive modular systems is considered. These systems consist of physically interconnected and generally heterogeneous modules, where local control signals can be only applied to a subset of these modules (i.e., active modules) and the rest are not subject to any control signals (i.e., passive modules). Using a set-theoretic adaptive control approach predicated on restricted potential functions, we design decentralized command following control architectures for each active module such that they can effectively perform their tasks with strict performance guarantees in the presence of unknown physical interconnections between modules and module-level system uncertainties. The efficacy of the …

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An Algorithm For Enlarging The Region Of Attraction Using Trajectory Reversing, Nilay Kant, Dhrubajit Chowdhury, Ranjan Mukherjee, Hassan K. Khalil Jun 2017

An Algorithm For Enlarging The Region Of Attraction Using Trajectory Reversing, Nilay Kant, Dhrubajit Chowdhury, Ranjan Mukherjee, Hassan K. Khalil

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Trajectory reversing is a method commonly used for estimating the region of attraction of stabilized equilibria. Using a discrete set of points obtained by trajectory reversing, this paper presents an algorithm for estimation and mathematical representation of the region of attraction using convex hulls. Several two-dimensional examples are presented to illustrate the usefulness of the algorithm. The method provides larger estimates compared to that obtained by existing algorithms, but its main advantage lies in its applicability to higher-order systems. The mathematical representation of the region of attraction is useful in applying the Impulse Manifold Method, which was developed for stabilization …

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