Direct Numerical Simulation Of A Pulsatile Flow In A Stenotic
Channel Using Immersed Boundary Method,
2021
University of Nebraska-Lincoln
Direct Numerical Simulation Of A Pulsatile Flow In A Stenotic Channel Using Immersed Boundary Method, Siamak Mirfendereski, Jae Sung Park
Department of Mechanical and Materials Engineering: Faculty Publications
A three-dimensional direct numerical simulation model coupled with the immersed boundary method has been developed to simulate a pulsatile flow in a planar channel with single and double one-sided semicircular constrictions. For relevance to blood flow in large arteries, simulations have been performed at Reynolds numbers of 750 and 1000. Flow physics and resultant wall shear stress (WSS)-based hemodynamic parameters are presented. The instantaneous vortex dynamics, mean flow characteristics, and turbulent energy spectra are evaluated for flow physics. Subsequently, three WSS-based parameters, namely the time-averaged WSS, oscillatory shear index, and relative residence time, are calculated over the stenotic wall and …
Large-Scale Synthesis Of Compressible And Re-Expandable
Three-Dimensional Nanofiber Matrices,
2021
University of Nebraska Medical Center
Large-Scale Synthesis Of Compressible And Re-Expandable Three-Dimensional Nanofiber Matrices, Alec Mccarthy, Lorenzo Saldana, Daniel Mcgoldrick, Johnson V. John, Mitchell Kuss, Shixuan Chen, Bin Duan, Mark A. Carlson, Jingwei Xie
Department of Mechanical and Materials Engineering: Faculty Publications
Due to their biomimetic properties, electrospun nanofibers have shown great potential in many biomedical fields. However, traditionally-produced nanofibers are typically two-dimensional (2D) membranes limiting their applications. Herein, we report a large-scale synthesis of compressible and reexpandable three-dimensional (3D) nanofiber matrices for potential biomedical applications. The reproducible mass production of such matrices is achieved using a multiple-emitter electrospinning machine with a controlled environment (e.g., temperature, humidity, and air flow rate) followed by an innovative gas-foaming expansion. The modified 20-emitter circular array with 3D-printed needle caps is capable of maintaining stable Taylor cones under extremely high flow rates. The introduction of such …
A Novel Large Animal Model Of Smoke
Inhalation-Induced Acute Respiratory Distress
Syndrome,
2021
University of Nebraska Medical Center
A Novel Large Animal Model Of Smoke Inhalation-Induced Acute Respiratory Distress Syndrome, Premila D. Leiphrakpam, Hannah R. Weber, Andrea Mccain, Roser Romaguera Matas, Ernesto Martinez Duarte, Keely L. Buesing
Department of Mechanical and Materials Engineering: Faculty Publications
Background: Acute respiratory distress syndrome (ARDS) is multifactorial and can result from sepsis, trauma, or pneumonia, amongst other primary pathologies. It is one of the major causes of death in critically ill patients with a reported mortality rate up to 45%. The present study focuses on the development of a large animal model of smoke inhalation-induced ARDS in an effort to provide the scientific community with a reliable, reproducible large animal model of isolated toxic inhalation injury-induced ARDS. Methods: Animals (n=21) were exposed to smoke under general anesthesia for 1 to 2 h (median smoke exposure=0.5 to 1 L of …
Assembly Of Close-Packed
Ferroelectric Polymer Nanowires
Via Interface-Epitaxy With Res2,
2021
University of Nebraska-Lincoln
Assembly Of Close-Packed Ferroelectric Polymer Nanowires Via Interface-Epitaxy With Res2, Dawei Li, Shuo Sun, Kun Wang, Zahra Ahmadi, Jeffrey E. Shield, Stephen Ducharme, Xia Hong
Department of Mechanical and Materials Engineering: Faculty Publications
The flexible, transparent, and low-weight nature of ferroelectric polymers makes them promising for wearable electronic and optical applications. To reach the full potential of the polarization-enabled device functionalities, large-scale fabrication of polymer thin films with well-controlled polar directions is called for, which remains a central challenge. The widely exploited Langmuir–Blodgett, spin-coating, and electrospinning methods only yield polymorphous or polycrystalline films, where the net polarization is compromised. Here, an easily scalable approach is reported to achieve poly(vinylidene fluoride-trifluoroethylene) P(VDF-TrFE) thin films composed of close-packed crystalline nanowires via interface-epitaxy with 1T′-ReS2. Upon controlled thermal treatment, uniform P(VDF-TrFE) films restructure into …
Reducing Corrosion Of Additive Manufactured Magnesium Alloys By Interlayer Ultrasonic Peening,
2021
University of Nebraska-Lincoln
Reducing Corrosion Of Additive Manufactured Magnesium Alloys By Interlayer Ultrasonic Peening, M. P. Sealy, R. Karunakaran, S. Ortgies, G. Madireddy, A. P. Malshe, K. P. Rajurkar
Department of Mechanical and Materials Engineering: Faculty Publications
Additive manufad (AM) magn alloys corrode rapidly due to tensile stress and coarse microstructures. Cyclically combining (hybridizing) additive manufacturing with interlayer ultrasonic peening was proposed as a solution to improve corrosion resistance of additive manufactured magnesium WE43 alloy through strengthening mechanisms and compressive residual stress. Applying interlayer peening work hardened discrete layers and formed a glocal integrity of regional grain refinement and subsurface compressive residual stress barriers. Tensile residual stress that typically accelerates corrosion decreased 90%. Results showed time-resolved control over corrosion was attainable by interlayer peening, and local corrosion within print cells decreased 57% with respect to as-printed WE43.
Ultra-Fast Charging In Aluminum-Ion Batteries: Electric Double Layers On Active Anode,
2021
Dalian University of Technology,
Ultra-Fast Charging In Aluminum-Ion Batteries: Electric Double Layers On Active Anode, Xuejing Shen, Tao Sun, Lei Yang, Alexey Krasnoslobodtsev, Renat F. Sabirianov, Michael P. Sealy, Wai-Ning Mei, Zhanjun Wu, Li Tan
Department of Mechanical and Materials Engineering: Faculty Publications
With the rapid iteration of portable electronics and electric vehicles, developing high-capacity batteries with ultra-fast charging capability has become a holy grail. Here we report rechargeable aluminum-ion batteries capable of reaching a high specific capacity of 200 mAh g−1. When liquid metal is further used to lower the energy barrier from the anode, fastest charging rate of 104 C (duration of 0.35 s to reach a full capacity) and 500% more specific capacity under high-rate conditions are achieved. Phase boundaries from the active anode are believed to encourage a high-flux charge transfer through the electric double layers. As …
Electron Microscopy Observation Of Electric Field-Assisted Sintering Of Stainless Steel Nanoparticles,
2021
University of Nebraska-Lincoln
Electron Microscopy Observation Of Electric Field-Assisted Sintering Of Stainless Steel Nanoparticles, Fei Wang, Qin Zhou, Xing-Zhong Li, Yongchul Yoo, Michael Nastasi, Bai Cui
Department of Mechanical and Materials Engineering: Faculty Publications
The intrinsic role of electrical current on the electric field-assisted sintering (EFAS) process of stainless steel 316L nanoparticles has been revealed by both ex situ and in situ experiments. A novel device on the Si chip has been designed and fabricated to fit into the sample holder of a transmission electron microscope for these experiments. The evolution of nanoparticle morphology and microstructures during the EFAS process has been studied using scanning electron microscopy and transmission electron microscopy, which has been combined with the simultaneous measurement of the electric voltage and current changes. A preliminary four-stage mechanism for the EFAS process …
Nondestructive Evaluation Of Aluminium Foam Panels Subjected To Impact Loading,
2021
University of Messina
Nondestructive Evaluation Of Aluminium Foam Panels Subjected To Impact Loading, Gabriella Epasto, Fabio Distefano, Hozhabar Mozafari, Emanoil Linul, Vincenzo Crupi
Department of Mechanical and Materials Engineering: Faculty Publications
Aluminium foam sandwich structures have excellent energy absorption capacity, combined with good mechanical properties and low density. Some of the authors of this paper proposed an innovative Metallic Foam Shell protective device against flying ballast impact damage in railway axles. A closed-cell aluminium foam was chosen for the Metallic Foam Shell device. The main goal of this study was the experimental investigation of the impact responses of aluminium foam panels. Low velocity impact tests were carried out at different energies on different types of aluminium foam panels in order to investigate the effects of some parameters, such as core thickness, …
The Role Of Microenvironmental Cues And Mechanical Loading Milieus In Breast Cancer Cell Progression And Metastasis,
2021
University of Nebraska-Lincoln
The Role Of Microenvironmental Cues And Mechanical Loading Milieus In Breast Cancer Cell Progression And Metastasis, Brandon D. Riehl, Eunju Kim, Tasneem Bouzid, Jung Yul Lim
Department of Mechanical and Materials Engineering: Faculty Publications
Cancer can disrupt the microenvironments and mechanical homeostatic actions in multiple scales from large tissue modification to altered cellular signaling pathway in mechanotransduction. In this review, we highlight recent progresses in breast cancer cell mechanobiology focusing on cell-microenvironment interaction and mechanical loading regulation of cells. First, the effects of microenvironmental cues on breast cancer cell progression and metastasis will be reviewed with respect to substrate stiffness, chemical/topographic substrate patterning, and 2D vs. 3D cultures. Then, the role of mechanical loading situations such as tensile stretch, compression, and flow-induced shear will be discussed in relation to breast cancer cell mechanobiology and …
Ligand Assisted Growth Of Perovskite Single Crystals
With Low Defect Density,
2021
University of North Carolina at Chapel Hill
Ligand Assisted Growth Of Perovskite Single Crystals With Low Defect Density, Ye Liu, Xiaopeng Zheng, Yanjun Fang, Ying Zhou, Zhenyi Ni, Xun Xiao, Shangshang Chen, Jinsong Huang
Department of Mechanical and Materials Engineering: Faculty Publications
A low defect density in metal halide perovskite single crystals is critical to achieve high performance optoelectronic devices. Here we show the reduction of defect density in per[1]ovskite single crystals grown by a ligand-assisted solution process with 3‐(decyldimethy[1]lammonio)‐propane‐sulfonate inner salt (DPSI) as an additive. DPSI ligands anchoring with lead ions on perovskite crystal surfaces not only suppress nucleation in solution, but also regulate the addition of proper ions to the growing surface, which greatly enhances the crystal quality. The grown CH3NH3PbI3 crystals show better crystallinity and a 23-fold smaller trap density of 7 × 10 …
Social Connectedness And Negative Affect Uniquely Explain Individual Differences In Response To Emotional Ambiguity,
2021
University of Nebraska - Lincoln
Social Connectedness And Negative Affect Uniquely Explain Individual Differences In Response To Emotional Ambiguity, Maital Neta, Rebecca L. Brock
Department of Mechanical and Materials Engineering: Faculty Publications
Negativity bias is not only central to mood and anxiety disorders, but can powerfully impact our decision-making across domains (e.g., financial, medical, social). This project builds on previous work examining negativity bias using dual-valence ambiguity. Specifically, although some facial expressions have a relatively clear negative (angry) or positive valence (happy), surprised expressions are interpreted negatively by some and positively by others, providing insight into one’s valence bias. Here, we examine putative sources of variability that distinguish individuals with a more negative versus positive valence bias using structural equation modeling. Our model reveals that one’s propensity toward negativity (operationalized as temperamental …
Generation Of Excited Species In A Streamer Discharge,
2021
Old Dominion University
Generation Of Excited Species In A Streamer Discharge, Shirshak K. Dhali
Electrical & Computer Engineering Faculty Publications
At or near atmospheric pressure, most transient discharges, particularly in molecular gases or gas mixture containing molecular gases, result in a space charge dominated transport called a streamer discharge. The excited species generation in such discharges forms the basis for plasma chemistry in most technological applications. In this paper, we simulate the propagation of streamers in atmospheric pressure N2 to understand the energy partitioning in the formation of various excited species and compare the results to a uniform Townsend discharge. The model is fully two-dimensional with azimuthal symmetry. The results show a significantly larger fraction of the energy goes …
Designing Transition Metal Chalcogenides Electrocatalyst Surfaces For High-Efficiency Water Oxidation,
2021
Missouri University of Science and Technology
Designing Transition Metal Chalcogenides Electrocatalyst Surfaces For High-Efficiency Water Oxidation, Umanga De Silva
Doctoral Dissertations
”The rising demand for energy security and reducing fossil fuel dependence has prompted researchers to search for a clean, sustainable, and efficient energy generation system with low environmental impact. Water electrolysis has been identified as one of the most important processes satisfying the above needs to generate hydrogen as a clean fuel. Two half-cell reactions of oxygen evolution reaction (OER) at the anode and hydrogen evolution reaction (HER) at the cathode comprise the main process of water electrolysis. However, the oxygen evolution reaction is the most crucial step for efficient water splitting. Traditionally, metal oxides have been utilized as catalysts …
Surface Enhanced Raman Spectroscopy Analysis Of Thin-Smear-Contamination On Hdd Read-Write Head,
2021
Graduate School
Surface Enhanced Raman Spectroscopy Analysis Of Thin-Smear-Contamination On Hdd Read-Write Head, Charin Seesomdee
Chulalongkorn University Theses and Dissertations (Chula ETD)
Surface-enhanced Raman spectroscopy (SERS) is one of the most powerful analytical techniques for the identification of molecules in microelectronics industry for failure analysis protocol. In this work, a dry-processed gold nanoclusters were prepared by magnetron sputtering deposition to promote the enhancement of the Raman signal for the best intensity gain from selected common polymers found in hard disk drive as surface contamination. The optimized sputtering conditions was applied for SERS on polycarbonate (PC), polyethylene terephthalate (PET), polypropylene (PP), and high-density polyethylene (HDPE). The Raman spectrum showed the average Raman signal intensity gain at about 114%, 78%, 254%, and 226% respectively. …
Investigating The Antitumor Effects Of A Dsrna-Nanoparticle Complex In An In Vitro Ovarian Cancer Model,
2021
Wilfrid Laurier University
Investigating The Antitumor Effects Of A Dsrna-Nanoparticle Complex In An In Vitro Ovarian Cancer Model, Aaron Lewis
Theses and Dissertations (Comprehensive)
An estimated 1 in 70 women will be diagnosed with ovarian cancer in their lifetime. Despite advanced detection and treatment methods, it remains a silent killer with an expected survival rate of 50%. A developing method in cancer treatment is the use of compounds that stimulate the immune system to aid in the body's fight against the disease. This project focused on the use of the potent immune stimulant double-stranded RNA (dsRNA), commercially available as polyinosinic:polycytidylic acid, poly(I:C), to induce cytotoxicity in two ovarian cancer cell lines; SKOV-3 and OVCAR-3. Some challenges exist with the delivery of dsRNA due to …
Treated Hfo2 Based Rram Devices With Ru, Tan, Tin As Top Electrode For In-Memory Computing Hardware,
2020
New Jersey Institute of Technology
Treated Hfo2 Based Rram Devices With Ru, Tan, Tin As Top Electrode For In-Memory Computing Hardware, Yuvraj Dineshkumar Patel
Theses
The scalability and power efficiency of the conventional CMOS technology is steadily coming to a halt due to increasing problems and challenges in fabrication technology. Many non-volatile memory devices have emerged recently to meet the scaling challenges. Memory devices such as RRAMs or ReRAM (Resistive Random-Access Memory) have proved to be a promising candidate for analog in memory computing applications related to inference and learning in artificial intelligence. A RRAM cell has a MIM (Metal insulator metal) structure that exhibits reversible resistive switching on application of positive or negative voltage. But detailed studies on the power consumption, repeatability and retention …
Novel Electrochemical Sensor Based On Integration Of Nanoporous Gold With Molecularly Imprinted Polymer For Detection Of Arsenic Ion(Iii),
2020
1. Key Laboratory for Green Processing of Chemical Engineering of Xinjiang Production and Construction Corps/School of Chemistry and Chemical Engineering, Shihezi University, Shihezi 832000, China;3. Xinjiang Xiangsheng New Material Technology Co., Ltd. Hami Xinjiang 839000, China;
Novel Electrochemical Sensor Based On Integration Of Nanoporous Gold With Molecularly Imprinted Polymer For Detection Of Arsenic Ion(Iii), Wu-Wei Ma, Qi-Gang Chang, Xiong-Fang Shi, Yan-Bin Tong, Li Zhou, Bang-Ce Ye, Jian-Jiang Lu, Jin-Hu Zhao
Journal of Electrochemistry
Arsenic, a toxic chemical element, is detrimental to environment and human health in particular. Therefore, the development of simple, fast, and accurate arsenic ion (As3+) detection methods has attracted extensive attention. In this work, an electrochemical sensor based on molecular imprinted polymer (MIP) and nano-porous gold (NPG) modified indium tin oxide (ITO) electrode (MIP/NPG/ITO) was developed for determination of As3+ in water with different quality. NPG with high conductivity, large specific surface area and high biocompatibility was prepared in situ on ITO surface by a green electrodeposition method using simple and controllable steps. Then, a layer of …
Core-Shell Structured Ru@Ptru Nanoflower Electrocatalysts Toward Alkaline Hydrogen Evolution Reaction,
2020
State Key Laboratory of Fine Chemicals, School of Chemical Engineering,Dalian University of Technology, Dalian 116024, Liaoning, China;
Core-Shell Structured Ru@Ptru Nanoflower Electrocatalysts Toward Alkaline Hydrogen Evolution Reaction, Xue-Liang Wang, Yuan-Yuan Cong, Chen-Xi Qiu, Sheng-Jie Wang, Jia-Qi Qin, Yu-Jiang Song
Journal of Electrochemistry
Water electrolysis for hydrogen production is beneficial for solving the problem of energy crisis and environmental issues. It is necessary to study highly active and cost-effective catalysts toward hydrogen evolution reaction (HER) to reduce the consumption of noble metals. Herein, we report the synthesis of core-shell structured Ru@Pt0.24Ru nanoflowers electrocatalyst by stepwise reduction of Ru and Pt precursors in the mixture of oleylamine and benzyl alcohol at 160 oC. The average diameter of the resultant Ru@Pt0.24Ru was 16.5±4.0 nm with a bulk atomic ratio between Pt and Ru of 0.24:1 and a surface ratio of …
Preparations And Photoelectrochemical Performances Of Rgo-Tio2 Nanotubes Arrays,
2020
1. State Key Laboratory of Physical Chemistry of Solid Surfaces, Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, Fujian, China;
Preparations And Photoelectrochemical Performances Of Rgo-Tio2 Nanotubes Arrays, Ze-Yang Zhang, Lan Sun, Chang-Jian Lin
Journal of Electrochemistry
Decorating TiO2 nanotube arrays with RGO to improve the photocatalytic activity of TiO2 nanotube arrays has been reported. For the reported RGO-TiO2 nanotube arrays, TiO2 nanotube arrays were prepared by anodizing the high-purity Ti foil in an organic electrolyte for multiple-step treatments, while RGO were deposited on TiO2 nanotube arrays by using cyclic voltammetry or other electrical reduction methods. To enhance the reduction degree and the coverage of RGO on the resultant RGO-TiO2 nanotube arrays, in this work, the one-step electrochemical anodization in hydrofluoric acid was used to fabricate TiO2 nanotube arrays with …
Microparticle Propulsion For In Vivo Navigation,
2020
Southern Methodist University
Microparticle Propulsion For In Vivo Navigation, Louis Rogowski
Mechanical Engineering Research Theses and Dissertations
Microscale propulsion impacts a diverse array of fields, with simplistic microrobots allowing for novel innovations in microscale surgery and drug delivery. Propulsion at the microscale is constrained by physics, with time-reversal and geometric symmetries limiting available propulsion mechanisms. However, certain fluid environments and surface coatings allow for the propulsion of microparticles through externally applied magnetic fields. Presented here is a detailed analysis of microparticles propelling using spontaneous symmetry breaking, flagella surface coatings, and multi-modal actuation mechanisms. Spontaneous symmetry breaking in nonlinearly viscoelastic fluids is presented for the first time in literature, with two equal and opposite propulsion states existing along …
