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Me-Em Enewsbrief, October-December 2020, Department Of Mechanical Engineering-Engineering Mechanics, Michigan Technological University Dec 2020

Me-Em Enewsbrief, October-December 2020, Department Of Mechanical Engineering-Engineering Mechanics, Michigan Technological University

Department of Mechanical Engineering-Engineering Mechanics eNewsBrief

No abstract provided.


Sustainable Drug Release From Polycaprolactone Coated Chitin‑Lignin Gel Fibrous Scaffolds, Turdimuhammad Abdullah, Kalamegam Gauthaman, Azadeh Mostafavi, Ahmed Alshahrie, Numan Salah, Pierfrancesco Morganti, Angelo Chianese, Ali Tamayol, Adnan Memic Nov 2020

Sustainable Drug Release From Polycaprolactone Coated Chitin‑Lignin Gel Fibrous Scaffolds, Turdimuhammad Abdullah, Kalamegam Gauthaman, Azadeh Mostafavi, Ahmed Alshahrie, Numan Salah, Pierfrancesco Morganti, Angelo Chianese, Ali Tamayol, Adnan Memic

Department of Mechanical and Materials Engineering: Faculty Publications

Non-healing wounds have placed an enormous stress on both patients and healthcare systems worldwide. Severe complications induced by these wounds can lead to limb amputation or even death and urgently require more effective treatments. Electrospun scaffolds have great potential for improving wound healing treatments by providing controlled drug delivery. Previously, we developed fibrous scaffolds from complex carbohydrate polymers [i.e. chitin-lignin (CL) gels]. However, their application was limited by solubility and undesirable burst drug release. Here, a coaxial electrospinning is applied to encapsulate the CL gels with polycaprolactone (PCL). Presence of a PCL shell layer thus provides longer shelf-life for the …


Optimal Control Of Active Nematics, Michael M. Norton, Piyush Grover, Michael F. Hagan, Seth Fraden Oct 2020

Optimal Control Of Active Nematics, Michael M. Norton, Piyush Grover, Michael F. Hagan, Seth Fraden

Department of Mechanical and Materials Engineering: Faculty Publications

In this work we present the first systematic framework to sculpt active nematic systems, using optimal control theory and a hydrodynamic model of active nematics. We demonstrate the use of two different control fields, (i) applied vorticity and (ii) activity strength, to shape the dynamics of an extensile active nematic that is confined to a disk. In the absence of control inputs, the system exhibits two attractors, clockwise and counterclockwise circulating states characterized by two co-rotating topological þ1 2 defects. We specifically seek spatiotemporal inputs that switch the system from one attractor to the other; we also examine phase-shifting perturbations. …


Microfluidic Systems With Embedded Cell Culture Chambers For High Throughput Biological Assays, Arian Jaberi, Amir Monemian Esfahani, Fariba Aghabaglou, Jae Sung Park, Sidy Ndao, Ali Tamayol, Ruiguo Yang Oct 2020

Microfluidic Systems With Embedded Cell Culture Chambers For High Throughput Biological Assays, Arian Jaberi, Amir Monemian Esfahani, Fariba Aghabaglou, Jae Sung Park, Sidy Ndao, Ali Tamayol, Ruiguo Yang

Department of Mechanical and Materials Engineering: Faculty Publications

The ability to generate chemical and mechanical gradients on chips is important both for creating biomimetic designs or enabling high-throughput assays. However, there is still a significant knowledge gap in the generation of mechanical and chemical gradients in a single device. In this study, we developed gradient-generating microfluidic circuits with integrated microchambers to allow cell culture and to introduce chemical and mechanical gradients to cultured cells. A chemical gradient is generated across the microchambers, exposing cells to a uniform concentration of drugs. The embedded microchamber also produces a mechanical gradient in the form of varied shear stresses induced upon cells …


Me-Em Enewsbrief, September 2020, Department Of Mechanical Engineering-Engineering Mechanics, Michigan Technological University Sep 2020

Me-Em Enewsbrief, September 2020, Department Of Mechanical Engineering-Engineering Mechanics, Michigan Technological University

Department of Mechanical Engineering-Engineering Mechanics eNewsBrief

No abstract provided.


Effect Of Motor-Assisted Elliptical Training Speed And Body Weight Support On Center Of Pressure Movement Variability, Farahnaz Fallahtafti, Chase M. Pfeifer, Thad W. Buster, Judith M. Burnfield Sep 2020

Effect Of Motor-Assisted Elliptical Training Speed And Body Weight Support On Center Of Pressure Movement Variability, Farahnaz Fallahtafti, Chase M. Pfeifer, Thad W. Buster, Judith M. Burnfield

Department of Mechanical and Materials Engineering: Faculty Publications

Background: A motor-assisted elliptical trainer is being used clinically to help individuals with physical disabilities regain and/or retain walking ability and cardiorespiratory fitness. Unknown is how the device’s training parameters can be used to optimize movement variability and regularity. This study examined the effect of motor-assisted elliptical training speed as well as body weight support (BWS) on center of pressure (CoP) movement variability and regularity during training. Methods: CoP was recorded using in-shoe pressure insoles as participants motor-assisted elliptical trained at three speeds (20, 40, and 60 cycles per minute) each performed at four BWS levels (0%, 20%, 40%, and …


Comparison Of Plantar Pressure Profile Of Young Adults During Training On Elliptical Devices And Overground Walking: A Pilot Study, Guilherme Manna Cesar, Thad W. Buster, Judith M. Burnfield Jul 2020

Comparison Of Plantar Pressure Profile Of Young Adults During Training On Elliptical Devices And Overground Walking: A Pilot Study, Guilherme Manna Cesar, Thad W. Buster, Judith M. Burnfield

Department of Mechanical and Materials Engineering: Faculty Publications

Background: Elliptical training may offer advantages over other cardiorespiratory exercises for those requiring podiatric care, since its constant double-limb support diminishes recurring high-impact plantar forces while allowing exercise in a functional, upright posture. Unknown is the impact of distinct elliptical models, that can alter user’s body mechanics, on potential variations in plantar pressure patterns.

Purpose: To compare plantar pressure variables while exercising on four ellipticals and walking.

Methods: For this cross-sectional pilot study, plantar pressure data were recorded from ten young adults while exercising on four ellipticals (True, Octane, Life Fitness, SportsArt) and walking overground. One-way repeated measures ANOVA identified …


Magnetically Induced Carrier Distribution In A Composite Rod Of Piezoelectric Semiconductors And Piezomagnetics, Guolin Wang, Jinxi Liu, Wenjie Feng, Jiashi Yang Jul 2020

Magnetically Induced Carrier Distribution In A Composite Rod Of Piezoelectric Semiconductors And Piezomagnetics, Guolin Wang, Jinxi Liu, Wenjie Feng, Jiashi Yang

Department of Mechanical and Materials Engineering: Faculty Publications

In this work, we study the behavior of a composite rod consisting of a piezoelectric semiconductor layer and two piezomagnetic layers under an applied axial magnetic field. Based on the phenomenological theories of piezoelectric semiconductors and piezomagnetics, a one-dimensional model is developed from which an analytical solution is obtained. The explicit expressions of the coupled fields and the numerical results show that an axially applied magnetic field produces extensional deformation through piezomagnetic coupling, the extension then produces polarization through piezoelectric coupling, and the polarization then causes the redistribution of mobile charges. Thus, the composite rod exhibits a coupling between the …


Open-Source Digitally Replicable Lab-Grade Scales, Benjamin R. Hubbard, Joshua M. Pearce Jun 2020

Open-Source Digitally Replicable Lab-Grade Scales, Benjamin R. Hubbard, Joshua M. Pearce

Michigan Tech Publications

This study provides designs for a low-cost, easily replicable open-source lab-grade digital scale that can be used as a precision balance. The design is such that it can be manufactured for use in most labs throughout the world with open-source RepRap-class material extrusion-based 3-D printers for the mechanical components and readily available open-source electronics including the Arduino Nano. Several versions of the design were fabricated and tested for precision and accuracy for a range of load cells. The results showed the open-source scale was found to be repeatable within 0.05 g with multiple load cells, with even better precision (0.005 …


Lstm-Based Anomaly Detection For Non-Linear Dynamical System, Yue Tan, Chungjing Hu, Kuan Zhang, Kan Zeng, Ethan A. Davis, Jae Sung Park Jun 2020

Lstm-Based Anomaly Detection For Non-Linear Dynamical System, Yue Tan, Chungjing Hu, Kuan Zhang, Kan Zeng, Ethan A. Davis, Jae Sung Park

Department of Mechanical and Materials Engineering: Faculty Publications

Anomaly detection for non-linear dynamical system plays an important role in ensuring the system stability. However, it is usually complex and has to be solved by large-scale simulation which requires extensive computing resources. In this paper, we propose a novel anomaly detection scheme in non-linear dynamical system based on Long Short-Term Memory (LSTM) to capture complex temporal changes of the time sequence and make multi-step predictions. Specifically, we first present the framework of LSTM-based anomaly detection in non-linear dynamical system, including data preprocessing, multi-step prediction and anomaly detection. According to the prediction requirement, two types of training modes are explored …


Me-Em Enewsbrief, June 2020, Department Of Mechanical Engineering-Engineering Mechanics, Michigan Technological University Jun 2020

Me-Em Enewsbrief, June 2020, Department Of Mechanical Engineering-Engineering Mechanics, Michigan Technological University

Department of Mechanical Engineering-Engineering Mechanics eNewsBrief

No abstract provided.


Fly Ash Based Geopolymer For High Temperature And High Compressive Strength Applications In Aggressive Environment, Aaryan Manoj Nair, Akm S. Rahman May 2020

Fly Ash Based Geopolymer For High Temperature And High Compressive Strength Applications In Aggressive Environment, Aaryan Manoj Nair, Akm S. Rahman

Publications and Research

Geopolymers are the results of geosynthetic reactions between aluminosilicates and strong bases. This results in chemical bonds between aluminum (Al), Silicon (Si)and oxygen (O) composing polymer rings in tetrahedral coordination. These bonds give them widespread useful applications such as high heat bearing ceramics, and base construction material whilst being far more environmentally conscious. The purpose of the experiment is to examine the effect of Silicon Carbide whisker and inorganic glass particles on thermal and mechanical properties of Geopolymers. This study will help understand the effect of various compositions and concentrations of SiO2 in mechanical strength. In this experiment, the …


A Wirelessly Controlled Smart Bandage With 3d-Printed Miniaturized Needle Arrays, Hossein Derakhshandeh, Fariba Aghabaglou, Alec Mccarthy, Azadeh Mostafavi, Chris Wiseman, Zack Bonick, Ian Ghanavati, Seth Harris, Craig Kreikemeier-Bower, Seyed Masoud Moosavi Basri, Jordan Rosenbohm, Ruiguo Yang, Pooria Mostafalu, Dennis Orgill, Ali Tamayol Mar 2020

A Wirelessly Controlled Smart Bandage With 3d-Printed Miniaturized Needle Arrays, Hossein Derakhshandeh, Fariba Aghabaglou, Alec Mccarthy, Azadeh Mostafavi, Chris Wiseman, Zack Bonick, Ian Ghanavati, Seth Harris, Craig Kreikemeier-Bower, Seyed Masoud Moosavi Basri, Jordan Rosenbohm, Ruiguo Yang, Pooria Mostafalu, Dennis Orgill, Ali Tamayol

Department of Mechanical and Materials Engineering: Faculty Publications

PUBLIC ACCESS


A Novel Self-Healing System: Towards A Sustainable Porous Asphalt, Shi Xu, Xueyan Liu, Amir Tabakovic, Erik Schlangen Mar 2020

A Novel Self-Healing System: Towards A Sustainable Porous Asphalt, Shi Xu, Xueyan Liu, Amir Tabakovic, Erik Schlangen

Articles

Self-healing asphalt, aimed to produce a sustainable asphalt pavement using green technology, has been studied in the past two decades. Technologies including encapsulated rejuvenator and induction heating have been proposed, demonstrated in the laboratory, and gradually evaluated in field application. This paper looks into the synergy effect of the above two technologies, where induction heating serves as the asphalt damage repair mechanism, requiring just 2 min heating time and encapsulated rejuvenator will replenish (rejuvenate) aged asphalt binder and reinstate bitumen’s healing ability. Moreover, the increased temperature from induction heating could in turn accelerate the diffusion process of rejuvenator into aged …


Me-Em Enewsbrief, March 2020, Department Of Mechanical Engineering-Engineering Mechanics, Michigan Technological University Mar 2020

Me-Em Enewsbrief, March 2020, Department Of Mechanical Engineering-Engineering Mechanics, Michigan Technological University

Department of Mechanical Engineering-Engineering Mechanics eNewsBrief

No abstract provided.


Cycle-To-Cycle Flow Variations In A Square Duct With A Symmetrically Oscillating Constriction, Erica Sherman, Lori M. Lambert, Bethany White, Michael H. Krane, Timothy Wei Feb 2020

Cycle-To-Cycle Flow Variations In A Square Duct With A Symmetrically Oscillating Constriction, Erica Sherman, Lori M. Lambert, Bethany White, Michael H. Krane, Timothy Wei

Department of Mechanical and Materials Engineering: Faculty Publications

Spatially and temporally resolved Digital Particle Image Velocimetry (DPIV) measurements are presented of flow complexities in a nominally two-dimensional, symmetric, duct with an oscillating constriction. The motivation for this research lies in advancing the state-of-the-art in applying integral control volume analysis to modeling unsteady internal flows. The specific target is acoustic modeling of human phonation. The integral mass and momentum equations are directly coupled to the acoustic equations and provide quantitative insight into acoustic source strengths in addition to the dynamics of the fluid-structure interactions in the glottis. In this study, a square cross-section duct was constructed with symmetric, computer …


Analyzing Concrete Beam Design: Verifying Predictions In T&Ee Classrooms, Andrew J. Hughes, Chris Merrill Jan 2020

Analyzing Concrete Beam Design: Verifying Predictions In T&Ee Classrooms, Andrew J. Hughes, Chris Merrill

Educational Leadership & Technology Faculty Publications

Design is often accepted as a fundamental aspect of engineering (Dym, et al., 2005). The design process is frequently portrayed as a set of steps. However, the design process is more complex than just a set of steps in a relatively fixed process. The complex nature of design, design thinking, questioning, and decision-making is exactly what technology and engineering classrooms are well suited to address. When addressing the question—“Why is technology and engineering education (T&EE) so important?”—the authors believe T&EE’s importance relates to our discipline’s ability to solve complex problems by balancing theory and practice in engaging hands-on learning scenarios …


Nanothermomechanical And And Or Logic Gates, Ahmed Hamed, Sidy Ndao Jan 2020

Nanothermomechanical And And Or Logic Gates, Ahmed Hamed, Sidy Ndao

Department of Mechanical and Materials Engineering: Faculty Publications

Today’s electronics cannot perform in harsh environments (e.g., elevated temperatures and ionizing radiation environments) found in many engineering applications. Based on the coupling between near-field thermal radiation and MEMS thermal actuation, we presented the design and modeling of NanoThermoMechanical AND, OR, and NOT logic gates as an alternative, and showed their ability to be combined into a full thermal adder to perform complex operations. in this work, we introduce the fabrication and characterization of the first ever documented Thermal AND and OR logic gates. Theresults show thermal logic operations can be achieved successfully through demonstrated and easy-to- manufacture nanothermoMechanical logic …


Variations In Plantar Pressure Variables Across Elliptical Trainers In Older Adults, Judith M. Burnfield, Guilherme Manna Cesar, Thad W. Buster Jan 2020

Variations In Plantar Pressure Variables Across Elliptical Trainers In Older Adults, Judith M. Burnfield, Guilherme Manna Cesar, Thad W. Buster

Department of Mechanical and Materials Engineering: Faculty Publications

Background: Ellipticals are used to address walking and cardiorespiratory training goals of older adults, some of whom are at risk for foot injuries. Variations in joint kinematics and muscle demands when using different ellipticals could lead to plantar pressure differences. This study explored plantar pressure variables during gait and use of four ellipticals.

Methods: Plantar pressures were recorded while 10 adults [68.1 (4.5) years] walked and used the True, Octane, Life Fitness, and SportsArt ellipticals. Repeated-measures ANOVAs (5 × 1) identified forefoot and heel differences across conditions.

Findings: Maximum forefoot forces and peak pressures were significantly lower than walking for …


Challenges In Path Planning Of High Energy Density Beams For Additive Manufacturing, Karunakaran K. P, Seema Negi, Arun Nambolan, Yogesh Patil, Milan Pandya, Sajan Kapil, Dmitriy Trushnikov, Michael P. Sealy, Alain Bernard Jan 2020

Challenges In Path Planning Of High Energy Density Beams For Additive Manufacturing, Karunakaran K. P, Seema Negi, Arun Nambolan, Yogesh Patil, Milan Pandya, Sajan Kapil, Dmitriy Trushnikov, Michael P. Sealy, Alain Bernard

Department of Mechanical and Materials Engineering: Faculty Publications

As there are no cutting forces in High Energy Density (HED) beams like lasers and Electron Beam (EB), their speeds are limited only by their positioning systems. On the other hand, as the entire matrix of the 3D printed part has to be addressed by the thin beam in multiple passes in multiple layers, they have to travel several kilometers in tiny motions. Therefore, the acceleration of the motion system becomes the limiting factor than velocity or precision. The authors have proposed an area-filling strategy for EB to fill the layer with optimal squares to exploit analog and hardware computing. …


Low- And High-Drag Intermittencies In Turbulent Channel Flows, Rishav Agrawal, Henry C.-H. Ng, Ethan A. Davis, Jae Sung Park, Michael D. Graham, David J.C. Dennis, Robert J. Poole Jan 2020

Low- And High-Drag Intermittencies In Turbulent Channel Flows, Rishav Agrawal, Henry C.-H. Ng, Ethan A. Davis, Jae Sung Park, Michael D. Graham, David J.C. Dennis, Robert J. Poole

Department of Mechanical and Materials Engineering: Faculty Publications

Recent direct numerical simulations (DNS) and experiments in turbulent channel flow have found intermittent low- and high-drag events in Newtonian fluid flows, at Reτ = uτh/ν between 70 and 100, where uτ, h and ν are the friction velocity, channel half-height and kinematic viscosity, respectively. These intervals of low-drag and high-drag have been termed “hibernating” and “hyperactive”, respectively, and in this paper, a further investigation of these intermittent events is conducted using experimental and numerical techniques. For experiments, simultaneous measurements of wall shear stress and velocity are carried out in a channel flow facility using hot-film anemometry (HFA) and laser …


Role Of Interfacial Transition Zones In The Fracture Of Cu/V Nanolamellar Multilayers, Siyuan Wei, Shijian Zheng, Lifeng Zhang, Yue Liu, Jian Wang, Xianping Wang, Jiangwei Wang Jan 2020

Role Of Interfacial Transition Zones In The Fracture Of Cu/V Nanolamellar Multilayers, Siyuan Wei, Shijian Zheng, Lifeng Zhang, Yue Liu, Jian Wang, Xianping Wang, Jiangwei Wang

Department of Mechanical and Materials Engineering: Faculty Publications

Plastic deformation and fracture behavior of Cu/V nanoscale metallic multilayers (NMMs) were systematically investigated through in situ transmission electron microscopy testing. Two different types of interfaces: sharp interfaces and interfacial transition zones (ITZs), formed in the as-fabricated Cu/V NMMs. Upon deformation, sharp interfaces and ITZs exert distinct influences on the fracture behavior of Cu/V NMMs. Sharp interfaces can impede the crack propagation by deflecting the crack propagation and blunting the crack tip, while the ITZs can induce microcracks and facilitate the fracture process. These findings shed light on the important roles of interface structures in the deformation of a broad …


An Overview Of Additive Manufacturing Technologies—A Review To Technical Synthesis In Numerical Study Of Selective Laser Melting, Abbas Razavykia, Eugenio Brusa, Cristiana Delprete, Reza Yavari Jan 2020

An Overview Of Additive Manufacturing Technologies—A Review To Technical Synthesis In Numerical Study Of Selective Laser Melting, Abbas Razavykia, Eugenio Brusa, Cristiana Delprete, Reza Yavari

Department of Mechanical and Materials Engineering: Faculty Publications

Additive Manufacturing (AM) processes enable their deployment in broad applications from aerospace to art, design, and architecture. Part quality and performance are the main concerns during AM processes execution that the achievement of adequate characteristics can be guaranteed, considering a wide range of influencing factors, such as process parameters, material, environment, measurement, and operators training. Investigating the effects of not only the influential AM processes variables but also their interactions and coupled impacts are essential to process optimization which requires huge efforts to be made. Therefore, numerical simulation can be an effective tool that facilities the evaluation of the AM …


Characteristic Boundaries Associated With Three-Dimensional Twins In Hexagonal Metals, Shujuan Wang, Mingyu Gong, Rodney J. Mccabe, Laurent Capolungo, Jian Wang, Carlos N. Tomé Jan 2020

Characteristic Boundaries Associated With Three-Dimensional Twins In Hexagonal Metals, Shujuan Wang, Mingyu Gong, Rodney J. Mccabe, Laurent Capolungo, Jian Wang, Carlos N. Tomé

Department of Mechanical and Materials Engineering: Faculty Publications

Twinning is a critically important deformation mode in hexagonal close-packed metals. Twins are three-dimensional (3D) domains, whose growth is mediated by the motion of facets bounding the 3D twin domains and influences work hardening in metals. An understanding of twin transformations therefore necessitates that the atomic-scale structure and intrinsic mobilities of facets be known and characterized. The present work addresses the former point by systematically characterizing the boundary structures of 3D { ̄1012} twins in magnesium using high-resolution transmission electron microscopy (HRTEM). Eight characteristic facets associated with twin boundaries are reported, five of which have never been experimentally observed before. …


Multi-Well Plate Channel Device With Reversible Seals, Haipeng Zhang, Timothy Wei, Sangjin Ryu Jan 2020

Multi-Well Plate Channel Device With Reversible Seals, Haipeng Zhang, Timothy Wei, Sangjin Ryu

Department of Mechanical and Materials Engineering: Faculty Publications

Atherosclerosis is a cardiovascular disease which causes over 26,000 yearly deaths in the United States. This disease involves accumulation of substances in arterial walls (or plaques) that occurs frequently to arterial regions experiencing low shear stress, such as bends and bifurcations. A possible reason of plaque growth in arterial walls is the change of endothelial cell (EC)’s shape, which is related to fluid shear stresses tangentially acting on intimal layer (the EC surface) of the arterial wall. Lambert et al. studied the relationship between EC shape and shear stress (Lambert et al., 2019) using a BioFlux system (Fluxion Bioscienes) and …


Electrospun Thymosin Beta-4 Loaded Plga/Pla Nanofiber/ Microfiber Hybrid Yarns For Tendon Tissue Engineering Application, Shaohua Wu, Rong Zhou, Fang Zhou, Philipp N. Streubel, Shaojuan Chen, Bin Duan Jan 2020

Electrospun Thymosin Beta-4 Loaded Plga/Pla Nanofiber/ Microfiber Hybrid Yarns For Tendon Tissue Engineering Application, Shaohua Wu, Rong Zhou, Fang Zhou, Philipp N. Streubel, Shaojuan Chen, Bin Duan

Department of Mechanical and Materials Engineering: Faculty Publications

Microfiber yarns (MY) have been widely employed to construct tendon tissue grafts. However, suboptimal ultrastructure and inappropriate environments for cell interactions limit their clinical application. Herein, we designed a modified electrospinning device to coat poly(lactic-co-glycolic acid) PLGA nanofibers onto polylactic acid (PLA) MY to generate PLGA/PLA hybrid yarns (HY), which had a well-aligned nanofibrous structure, resembling the ultrastructure of native tendon tissues and showed enhanced failure load compared to PLA MY. PLGA/PLA HY significantly improved the growth, proliferation, and tendon-specific gene expressions of human adipose derived mesenchymal stem cells (HADMSC) compared to PLA MY. Moreover, thymosin beta-4 (Tβ4) loaded PLGA/PLA …


Three-Dimensional Characterization Of Peripapillary Retinal Pigment Epithelium-Basement Membrane Layer In Patients Following Lumbar Puncture, Junfei Tong, Pengfei Dong, Sachin Kedar, Deepta Ghate, Linxia Gu Jan 2020

Three-Dimensional Characterization Of Peripapillary Retinal Pigment Epithelium-Basement Membrane Layer In Patients Following Lumbar Puncture, Junfei Tong, Pengfei Dong, Sachin Kedar, Deepta Ghate, Linxia Gu

Department of Mechanical and Materials Engineering: Faculty Publications

Purpose: To develop and test an innovative semi-automatic method for quantifying the three-dimensional morphology of the peripapillary retinal pigment epithelium-basement membrane (ppRPE/BM) layer, with application to lumbar puncture (LP) patients. Methods: Nineteen patients undergoing LP were recruited. The optic nerve head images of both eyes were acquired in 12 radial directions using optical coherence tomography (OCT) before and after LP. For each OCT image, the ppRPE/BM layer was automatically segmented with manual corrections by independent graders when necessary. The linear regression model of the ppRPE/BM layer was fitted using the least squares approach, and the ppRPE/BM layer angle was measured …


Additive Manufacturing Of Magnesium Alloys, Rakeshkumar Karunakaran, Sam Ortgies, Ali Tamayol, Florin Bobaru, Michael P. Sealy Jan 2020

Additive Manufacturing Of Magnesium Alloys, Rakeshkumar Karunakaran, Sam Ortgies, Ali Tamayol, Florin Bobaru, Michael P. Sealy

Department of Mechanical and Materials Engineering: Faculty Publications

Magnesium alloys are a promising new class of degradable biomaterials that have a similar stiffness to bone, which minimizes the harmful effects of stress shielding. Use of biodegradable magnesium implants eliminates the need for a second surgery for repair or removal. There is a growing interest to capitalize on additive manufacturing's unique design capabilities to advance the frontiers of medicine. However, magnesium alloys are difficult to 3D print due to the high chemical reactivity that poses a combustion risk. Furthermore, the low vaporization temperature of magnesium and common biocompatible alloying elements further increases the difficulty to print fully dense structures …


Passivation Of Defects In Perovskite Materials For Improved Solar Cell Efficiency And Stability, Jinsong Huang, Xiaopeng Zheng Jan 2020

Passivation Of Defects In Perovskite Materials For Improved Solar Cell Efficiency And Stability, Jinsong Huang, Xiaopeng Zheng

Department of Mechanical and Materials Engineering: Faculty Publications

Semiconductor devices, and methods of forming the same, include a cathode layer, an anode layer, and an active layer disposed between the cathode layer and the anode layer, wherein the active layer includes a perovskite layer. A passivation layer is disposed directly on a surface of the active layer between the cathode layer and the active layer, the passivation layer including a layer of material that passivates both cationic and anionic defects in the surface of the active layer.


Universal Mechanical Exfoliation Of Large-Area 2d Crystals, Yuan Huang, Yu-Hao Pan, Rong Yang, Li-Hong Bao, Lei Meng, Hai-Lan Luo, Yong-Qing Cai, Guo-Dong Liu, Wen-Juan Zhao, Zhang Zhou, Liang-Mei Wu, Zhi-Li- Zhu, Ming Huang, Li-Wei Liu, Lei Liu, Peng Cheng, Ke-Hui Wu, Shi-Bing Tian, Chang-Zhi Gu, You-Guo Shi, Yan-Feng Guo, Zhi Gang Cheng, Jiang-Ping Hu, Lin Zhao, Guan-Hua Yang, Eli Sutter, Peter Sutter, Ye-Liang Wang, Wei Ji, Xing-Jiang Zhou, Hong-Jun Gao Jan 2020

Universal Mechanical Exfoliation Of Large-Area 2d Crystals, Yuan Huang, Yu-Hao Pan, Rong Yang, Li-Hong Bao, Lei Meng, Hai-Lan Luo, Yong-Qing Cai, Guo-Dong Liu, Wen-Juan Zhao, Zhang Zhou, Liang-Mei Wu, Zhi-Li- Zhu, Ming Huang, Li-Wei Liu, Lei Liu, Peng Cheng, Ke-Hui Wu, Shi-Bing Tian, Chang-Zhi Gu, You-Guo Shi, Yan-Feng Guo, Zhi Gang Cheng, Jiang-Ping Hu, Lin Zhao, Guan-Hua Yang, Eli Sutter, Peter Sutter, Ye-Liang Wang, Wei Ji, Xing-Jiang Zhou, Hong-Jun Gao

Department of Mechanical and Materials Engineering: Faculty Publications

Two-dimensional materials provide extraordinary opportunities for exploring phenomena arising in atomically thin crystals. Beginning with the first isolation of graphene, mechanical exfoliation has been a key to provide high-quality two-dimensional materials, but despite improvements it is still limited in yield, lateral size and contamination. Here we introduce a contamination-free, one-step and universal Au-assisted mechanical exfoliation method and demonstrate its effectiveness by isolating 40 types of single-crystalline monolayers, including elemental two-dimensional crystals, metal-dichalcogenides, magnets and superconductors. Most of them are of millimeter-size and high-quality, as shown by transfer-free measure- ments of electron microscopy, photo spectroscopies and electrical transport. Large sus- pended …