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A Hamiltonian Surface-Shaping Approach For Control System Analysis And The Design Of Nonlinear Wave Energy Converters, Shadi Darani, Ossama Abdelkhalik, Rush D. Robinett III, David Wilson 2019 Michigan Technological University

A Hamiltonian Surface-Shaping Approach For Control System Analysis And The Design Of Nonlinear Wave Energy Converters, Shadi Darani, Ossama Abdelkhalik, Rush D. Robinett Iii, David Wilson

Department of Mechanical Engineering-Engineering Mechanics Publications

The dynamic model of Wave Energy Converters (WECs) may have nonlinearities due to several reasons such as a nonuniform buoy shape and/or nonlinear power takeoff units. This paper presents the Hamiltonian Surface-Shaping (HSS) approach as a tool for the analysis and design of nonlinear control of WECs. The Hamiltonian represents the stored energy in the system and can be constructed as a function of the WEC’s system states, its position, and velocity. The Hamiltonian surface is defined by the energy storage, while the system trajectories are constrained to this surface and determined by the power flows of the ...


Electrical System For Bioelectric Impedance Using Ad5933 Impedance Converter, Allison Garcia, Ahmet C. Sabuncu 2019 Southern Methodist University

Electrical System For Bioelectric Impedance Using Ad5933 Impedance Converter, Allison Garcia, Ahmet C. Sabuncu

SMU Journal of Undergraduate Research

Benchtop lab equipment, such as the HP4194A Precision Impedance Analyzer, offer accuracy and functionality but are often expensive and bulky. Although integrated circuits offer less functionality than benchtop equivalents, they can be a cheaper alternative for smaller applications. In this study, the AD5933 Impedance Converter was investigated as a low-cost option for impedance analysis of the bicep brachii. The AD5933 evaluation board was properly calibrated to measure human muscle by using an equivalent parallel circuit consisting of a 5 nF capacitor and a 1 kOhm resistor. Next, the impedance of the bicep was measured using the AD5933 as the experimental ...


Optimal Control Of Wave Energy Converters, Ossama Abdelkhalik, Rush D. Robinett III, Shangyan Zou, Giorgio Bacelli, David G. Wilson, Umesh Korde 2019 Michigan Technological University

Optimal Control Of Wave Energy Converters, Ossama Abdelkhalik, Rush D. Robinett Iii, Shangyan Zou, Giorgio Bacelli, David G. Wilson, Umesh Korde

Michigan Tech Patents

A wave energy converter and method for extracting energy from water waves maximizes the energy extraction per cycle by estimating an excitation force of heave wave motion on the buoy, computing a control force from the estimated excitation force using a dynamic model, and applying the computed control force to the buoy to extract energy from the heave wave motion. Analysis and numerical simulations demonstrate that the optimal control of a heave wave energy converter is, in general, in the form of a bang-singular-bang control; in which the optimal control at a given time can be either in the singular ...


Strength And Plasticity Of Amorphous Silicon Oxycarbide, Kaisheng Ming, Chao Gu, Qing Su, Yongqiang Wang, Arezoo Zare, Don A. Lucca, Michael Nastasi, Jian Wang 2019 University of Nebraska-Lincoln

Strength And Plasticity Of Amorphous Silicon Oxycarbide, Kaisheng Ming, Chao Gu, Qing Su, Yongqiang Wang, Arezoo Zare, Don A. Lucca, Michael Nastasi, Jian Wang

Mechanical & Materials Engineering Faculty Publications

Amorphous SiOC films were synthesized by magnetron sputtering at room temperature with/without radio frequency (RF) bias and further improved in terms of mechanical properties by ion irradiation. As-deposited SiOC films without RF bias exhibit catastrophic failure at a low stress and strain, which is ascribed to microstructural heterogeneities associated with the formation of voids during deposition, as evidenced by transmission electron microscopy. Ion irradiation unifies microstructure accompanied with eliminating the voids, resulting in a simultaneously increase in strength and plasticity (ultimate strength of 5–7 GPa and the strain to shear instability of over 20%). Homogeneous microstructures are demonstrated ...


Bouncing Dynamics Of A Class Of Mem/Nem Switching Systems, Mohamed Bognash 2019 The University of Western Ontario

Bouncing Dynamics Of A Class Of Mem/Nem Switching Systems, Mohamed Bognash

Electronic Thesis and Dissertation Repository

The aim of the present research is to understand the bouncing dynamic behavior of NEM/MEM switches in order to improve the switch performance and reliability. It is well known that the bouncing can dramatically degrade the switch performance and life; hence, in the present study, bouncing dynamics of a cantilever-based NME/MEM switch has been studied in detail. To this end, a model of a MEM switch that incorporates electrostatic force, squeeze film air damping force as well as asperity-based contact force has been proposed for an electrostatically actuated switch. An actuation force due to piezoelectric effects is further ...


In Situ Mechanical Characterization Of The Mixed- Mode Fracture Strength Of The Cu/Si Interface For Tsv Structures, Chenglin Wu, Congjie Wei, Yanxiao Li 2019 Missouri University of Science and Technology

In Situ Mechanical Characterization Of The Mixed- Mode Fracture Strength Of The Cu/Si Interface For Tsv Structures, Chenglin Wu, Congjie Wei, Yanxiao Li

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

In situ nanoindentation experiments have been widely adopted to characterize material behaviors of microelectronic devices. This work introduces the latest developments of nanoindentation experiments in the characterization of nonlinear material properties of 3D integrated microelectronic devices using the through-silicon via (TSV) technique. The elastic, plastic, and interfacial fracture behavior of the copper via and matrix via interface were characterized using small-scale specimens prepared with a focused ion beam (FIB) and nanoindentation experiments. A brittle interfacial fracture was found at the Cu/Si interface under mixed-mode loading with a phase angle ranging from 16.7° to 83.7°. The mixed-mode fracture ...


Feed Control: Composite Recycle, Rosy Perez 2019 Central Washington University

Feed Control: Composite Recycle, Rosy Perez

All Undergraduate Projects

The Boeing Company gave Central Washington University an opportunity for students to research and come up with an idea to reduce costs and landfill waste caused by the trimmings from the 777x composite wing pieces. The engineering and manufacturing for this project is about transporting composite material through to the delamination and chipper process. The delamination process uses a ram to press two claw shaped devices together that bends and deforms the material in opposite directions. The chipper process uses counter rotating saw blades spaced 1/8” apart to produce small shredded material. It is important for this newly designed ...


An Integrated Framework For Solid Modeling And Structural Analysis Of Layered Composites With Defects, Onur Rauf Bingol, Bryan Schiefelbein, Robert J. Grandin, Stephen D. Holland, Adarsh Krishnamurthy 2019 Iowa State University

An Integrated Framework For Solid Modeling And Structural Analysis Of Layered Composites With Defects, Onur Rauf Bingol, Bryan Schiefelbein, Robert J. Grandin, Stephen D. Holland, Adarsh Krishnamurthy

Center for Nondestructive Evaluation Publications

Laminated fiber-reinforced polymer (FRP) composites are widely used in aerospace and automotive industries due to their combined properties of high strength and low weight. However, owing to their complex structure, it is difficult to assess the impact of manufacturing defects and service damage on their residual life. Non-destructive evaluation (NDE) of composites using ultrasonic testing (UT) can identify the presence of defects. However, manually incorporating the damage in a CAD model of a multi-layered composite structure and evaluating its structural integrity is a tedious process. We have developed an automated framework to create a layered 3D CAD model of a ...


Resistance To Helium Bubble Formation In Amorphous Sioc/Crystalline Fe Nanocomposite, Qing Su, Tianyao Wang, Jonathan Gigax, Lin Shao, Michael Nastasi 2019 University of Nebraska-Lincoln

Resistance To Helium Bubble Formation In Amorphous Sioc/Crystalline Fe Nanocomposite, Qing Su, Tianyao Wang, Jonathan Gigax, Lin Shao, Michael Nastasi

Mechanical & Materials Engineering Faculty Publications

The management of radiation defects and insoluble He atoms represent key challenges for structural materials in existing fission reactors and advanced reactor systems. To examine how crystalline/amorphous interface, together with the amorphous constituents affects radiation tolerance and He management, we studied helium bubble formation in helium ion implanted amorphous silicon oxycarbide (SiOC) and crystalline Fe composites by transmission electron microscopy (TEM). The SiOC/Fe composites were grown via magnetron sputtering with controlled length scale on a surface oxidized Si (100) substrate. These composites were subjected to 50 keV He+ implantation with ion doses chosen to produce a 5 at ...


High Strength, Deformable Nanotwinned Al–Co Alloys, S. Xue, Qiang Li, D. Y. Xie, Y. F. Zhang, Han Wang, Haiyan Wong, J. Wang, Xinghang Zhang 2019 Purdue University

High Strength, Deformable Nanotwinned Al–Co Alloys, S. Xue, Qiang Li, D. Y. Xie, Y. F. Zhang, Han Wang, Haiyan Wong, J. Wang, Xinghang Zhang

Mechanical & Materials Engineering Faculty Publications

Aluminum (Al) alloys have been widely used in the transportation industry. However, most highstrength Al alloys to date have limited mechanical strength, on the order of a few hundred MPa, which is much lower than the flow stress of high-strength steels. In this study, we show the fabrication of nanocrystalline Al alloys with high-density growth twins enabled by a few atomic percent of Co solute. In situ uniaxial compression tests show that the flow stress of Al–Co solid solution alloys exceeds 1.5 GPa, while good work hardening capability is maintained. This study provides a new perspective on the ...


A Sensorless Force-Feedback System For Robot-Assisted Laparoscopic Surgery, Baoliang Zhao, Carl A. Nelson 2019 Chinese Academy of Sciences

A Sensorless Force-Feedback System For Robot-Assisted Laparoscopic Surgery, Baoliang Zhao, Carl A. Nelson

Mechanical & Materials Engineering Faculty Publications

The existing surgical robots for laparoscopic surgery offer no or limited force feedback, and there are many problems for the traditional sensor-based solutions. This paper builds a teleoperation surgical system and validates the effectiveness of sensorless force feedback. The tool-tissue interaction force at the surgical grasper tip is estimated using the driving motor’s current, and fed back to the master robot with a position-force bilateral control algorithm. The stiffness differentiation experiment and tumor detection experiment were conducted. In the stiffness differentiation experiment, 43 out of 45 pairs of ranking relationships were identified correctly, yielding a success rate of 96 ...


Hemodynamics And Wall Mechanics After Surgical Repair Of Aortic Arch: Implication For Better Clinical Decisions, Siyeong Ju, Ibrahim Abdullah, Shengmao Lin, Linxia Gu 2019 University of Nebraska - Lincoln

Hemodynamics And Wall Mechanics After Surgical Repair Of Aortic Arch: Implication For Better Clinical Decisions, Siyeong Ju, Ibrahim Abdullah, Shengmao Lin, Linxia Gu

Mechanical & Materials Engineering Faculty Publications

Graft repair of aortic coarctation is commonly used to mimic the physiological aortic arch shape and function. Various graft materials and shapes have been adopted for the surgery. The goal of this work is to quantitatively assess the impact of graft materials and shapes in the hemodynamics and wall mechanics of the restored aortic arch and its correlation with clinical outcomes. A three-dimensional aortic arch model was reconstructed from magnetic resonance images. The fluid–structure interaction (FSI) analysis was performed to characterize the hemodynamics and solid wall mechanics of the repaired aortic arch. Two graft shapes (i.e., a half-moon ...


Interface Facilitated Reorientation Of Mg Nanolayers In Mg-Nb Nanolaminates, Y. CHen, Mingyu Gong, N. A. Mara, Jian Wang 2019 University of Minnesota, Minneapolis

Interface Facilitated Reorientation Of Mg Nanolayers In Mg-Nb Nanolaminates, Y. Chen, Mingyu Gong, N. A. Mara, Jian Wang

Mechanical & Materials Engineering Faculty Publications

Mg/Nb nanolaminates synthesized through vapor deposition techniques exhibit high flow strength without conventional twinning in Mg. In this work, we investigated the influence of laminated microstructures on deformation mechanisms of Mg nanolayers. Using molecular dynamics simulations, we explored that (0001)-oriented Mg layers transform or re-orient to {10¯10}-oriented Mg layers through nucleation and growth of {10¯12} twins by atomic shuffling, instead of conventional {10¯12} twinning shear. Such a reorientation accommodates in-plane compressive strain and out-of-plane tensile strain when Mg/Nb laminates are subjected to compression parallel to the Mg/Nb interfaces. The nucleation of {10 ...


Predictive Peridynamic 3d Models Of Pitting Corrosion In Stainless Steel With Formation Of Lacy Covers, Siavash Jafarzadeh, Florin Bobaru, Ziguang Chen 2019 University of Nebraska-Lincoln

Predictive Peridynamic 3d Models Of Pitting Corrosion In Stainless Steel With Formation Of Lacy Covers, Siavash Jafarzadeh, Florin Bobaru, Ziguang Chen

Mechanical & Materials Engineering Faculty Publications

In this work, the peridynamic corrosion model is used for 3D simulation of pitting corrosion in stainless steel. Models for passivation and salt layer formation are employed to predict detailed characteristics of pit growth kinetic in stainless steels, such as lacy cover formation on top of the pit, and the diffusion-controlled regime at the pit bottom. The model is validated against an experimentally grown pit on 316L stainless steel in NaCl solution. Lacy covers in this model are formed autonomously during the simulation process. They are remarkably similar to the covers observed on top of the real pits.


Relative Contributions Of Intracranial Pressure And Intraocular Pressure On Lamina Cribrosa Behavior, Junfei Tong, Deepta Ghate, Sachin Kedar, Linxia Gu 2019 University of Nebraska - Lincoln

Relative Contributions Of Intracranial Pressure And Intraocular Pressure On Lamina Cribrosa Behavior, Junfei Tong, Deepta Ghate, Sachin Kedar, Linxia Gu

Mechanical & Materials Engineering Faculty Publications

Purpose. To characterize the relative contributions of intraocular pressure (IOP) and intracranial pressure (ICP) on lamina cribrosa (LC) behavior, specifically LC depth (LCD) and LC peak strain. Methods. An axially symmetric finite element model of the posterior eye was constructed with an elongated optic nerve and retro-orbital subarachnoid space ensheathed by pia and dura mater. -e mechanical environment in LC was evaluated with ICP ranging from 5 to 15mmHg and IOP from 10 to 45 mmHg. LCD and LC peak strains at various ICP and IOP levels were estimated using full factorial experiments. Multiple linear regression analyses were then applied ...


The Role Of Low-Level Image Features In The Affective Categorization Of Rapidly Presented Scenes, L. Jack Rhodes, Matthew Rios, Jacob M. Williams, Gonzalo Quinones, Prahalada K. Rao, Vladimir Miskovic 2019 State University of New York at Binghamton

The Role Of Low-Level Image Features In The Affective Categorization Of Rapidly Presented Scenes, L. Jack Rhodes, Matthew Rios, Jacob M. Williams, Gonzalo Quinones, Prahalada K. Rao, Vladimir Miskovic

Mechanical & Materials Engineering Faculty Publications

It remains unclear how the visual system is able to extract affective content from complex scenes even with extremely brief (< 100 millisecond) exposures. One possibility, suggested by findings in machine vision, is that low-level features such as unlocalized, two-dimensional (2-D) Fourier spectra can be diagnostic of scene content. To determine whether Fourier image amplitude carries any information about the affective quality of scenes, we first validated the existence of image category differences through a support vector machine (SVM) model that was able to discriminate our intact aversive and neutral images with ~ 70% accuracy using amplitude-only features as inputs. This model allowed us to confirm that scenes belonging to different affective categories could be mathematically distinguished on the basis of amplitude spectra alone. The next question is whether these same features are also exploited by the human visual system. Subsequently, we tested observers’ rapid classification of affective and neutral naturalistic scenes, presented briefly (~33.3 ms) and backward masked with synthetic textures. We tested categorization accuracy across three distinct experimental conditions, using: (i) original images, (ii) images having their amplitude spectra swapped within a single affective image category (e.g., an aversive image whose amplitude spectrum has been swapped with another aversive image) or (iii) images having their amplitude spectra swapped between affective categories (e.g., an aversive image containing the amplitude spectrum of a neutral image). Despite its discriminative potential, the human visual system does not seem to use Fourier amplitude differences as the chief strategy for affectively categorizing scenes at a glance. The contribution of image amplitude to affective categorization is largely dependent on interactions with the phase spectrum, although it is impossible to completely rule out a residual role for unlocalized 2-D amplitude measures.


Monolithic Heat-Transfer Device, Sidy Ndao, George Gogos, Dennis Alexander, Troy Anderson, Craig Zuhlke 2019 Lincoln, NE

Monolithic Heat-Transfer Device, Sidy Ndao, George Gogos, Dennis Alexander, Troy Anderson, Craig Zuhlke

Mechanical & Materials Engineering Faculty Publications

A monolithic heat-transfer device can include a container wall configured to retain a working fluid, where the container wall is formed of a single material. The container wall also includes an interior surface configured to be in fluid communication with the working fluid. The monolithic heat-transfer device also includes a channel disposed in the interior surface of the container wall, where the channel comprises a microstructure and a nanostructure. The microstructure and the nanostructure are materially contiguous with the single material forming the container wall. In some embodiments, the nanostructure comprises one or more layers of nanoparticles. The monolithic heat-transfer ...


Predictive Peridynamic 3d Models Of Pitting Corrosion In Stainless Steel With Formation Of Lacy Covers, Siavash Jafarzadeh, Florin Bobaru, Ziguang Chen 2019 University of Nebraska-Lincoln

Predictive Peridynamic 3d Models Of Pitting Corrosion In Stainless Steel With Formation Of Lacy Covers, Siavash Jafarzadeh, Florin Bobaru, Ziguang Chen

Mechanical & Materials Engineering Faculty Publications

In this work, the peridynamic corrosion model is used for 3D simulation of pitting corrosion in stainless steel. Models for passivation and salt layer formation are employed to predict detailed characteristics of pit growth kinetic in stainless steels, such as lacy cover formation on top of the pit, and the diffusion-controlled regime at the pit bottom. The model is validated against an experimentally grown pit on 316L stainless steel in NaCl solution. Lacy covers in this model are formed autonomously during the simulation process. They are remarkably similar to the covers observed on top of the real pits.


Higher-Order Overtone Thickness-Shear Vibrations Of Multilayered Thin-Film Acoustic Wave Resonators And Angular Rate Sensing, Hui Chen, Ji Wang, Jianke Du, Jiashi Yang 2019 Ningbo University

Higher-Order Overtone Thickness-Shear Vibrations Of Multilayered Thin-Film Acoustic Wave Resonators And Angular Rate Sensing, Hui Chen, Ji Wang, Jianke Du, Jiashi Yang

Mechanical & Materials Engineering Faculty Publications

We propose a new structure for piezoelectric gyroscopes. It is made from multilayered thin films of AlN or ZnO with alternating c-axes along the film thickness. It is shown theoretically that when such a film is electrically driven into higher-order overtone thickness-shear vibration in one of the two in-plane directions of the film and is rotating about the film normal, the Coriolis force due to the rotation causes a higher-order overtone thicknessshear vibration in a perpendicular direction with an electrical output that can be used to measure the angular rate of the rotation. Different from existing thickness-shear mode piezoelectric gyroscopes ...


3d Printing Of Hybrid Mos2-Graphene Aerogels As Highly Porous Electrode Materials For Sodium Ion Battery Anodes, Emery Brown, Pengli Yan, Halil Tekik, Ayyappan Elangovan, Jian Wang, Dong Lin, Jun Li 2019 Kansas State University

3d Printing Of Hybrid Mos2-Graphene Aerogels As Highly Porous Electrode Materials For Sodium Ion Battery Anodes, Emery Brown, Pengli Yan, Halil Tekik, Ayyappan Elangovan, Jian Wang, Dong Lin, Jun Li

Mechanical & Materials Engineering Faculty Publications

This study reports a 3D freeze-printing method that integrates inkjet printing and freeze casting to control both the microstructure and macroporosity via formation of ice microcrystals during printing. A viscous aqueous ink consisting of a molecular MoS2 precursor (ammonium thiomolybdate) mixed with graphene oxide (GO) nanosheets is used in the printing process. Post-treatments by freeze-drying and reductive thermal annealing convert the printed intermediate mixture into a hybrid structure consisting of MoS2 nanoparticles anchored on the surface of 2D rGO nanosheets in a macroporous framework, which is fully characterized with FESEM, TEM, XRD, Raman spectroscopy and TGA. The resulting ...


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