Engineering Science and Materials Commons^™

Predictive Modeling Of Oxygen Transmission Through Micro-Perforations For Packaging Applications, Ayman Abdellatief, Bruce A. Welt, Jason Butler, Eric Mclamore, Arthur Teixeira, Sanjay Shukla

Journal of Applied Packaging Research

Methods for creating precise perforations in respiring produce packaging are being increasingly adopted. Knowledge of oxygen transfer through perforated packaging and oxygen distribution in packages is necessary for successful packaging design of fresh produce. An approach to modeling perforated packaging performance was developed using a cylindrical chamber with precision perforations using Fick’s second law. The model was simulated using two techniques including Finite Element Method (FEM) using commercially available software and Finite Volume Method (FVM) through programming. Perforations were approximated as a source term in the second method. Both simulation techniques showed trends similar to experimental data.

Characterizing Water As Gap Fill For Double Glazing Units, Bright Adu

Masters Theses & Specialist Projects

The use of sunlight has always been a major goal in the design and operation of commercial buildings to minimize electrical consumption of artificial lighting systems. Glazing systems designed to allow optimal visible light transmission also allow significant unwanted direct solar heat gain caused by infrared light. Conversely, glazing systems that are designed to reflect unwanted direct solar heat gain significantly reduce the transmittance of visible light through windows. The goal of this research was to characterize the performance of water as gap-fill for double-glazing units in eliminating the compromises that exist in current glazing systems with respect to light …

The Effect Of Noise On The Response Of A Vertical Cantilever Beam Energy Harvester, Michael I. Friswell, Onur Bilgen, S. Faruque Ali, Grzegorz Litak, Sondipon Adhikari

Mechanical & Aerospace Engineering Faculty Publications

An energy harvesting concept has been proposed comprising a piezoelectric patch on a vertical cantilever beam with a tip mass. The cantilever beam is excited in the transverse direction at its base. This device is highly nonlinear with two potential wells for large tip masses, when the beam is buckled. For the pre-buckled case considered here, the stiffness is low and hence the displacement response is large, leading to multiple solutions to harmonic excitation that are exploited in the harvesting device. To maximise the energy harvested in systems with multiple solutions the higher amplitude response should be preferred. This paper …

High Pressure Behavior Of Mullite-Type Oxides: Phase Transitions, Amorphization, Negative Linear Compressibility And Microstructural Implications, Patricia Kalita

UNLV Theses, Dissertations, Professional Papers, and Capstones

Even though mullite occurs rarely in nature, it is perhaps one of the most important phases in both traditional and advanced ceramics. Existing and emerging applications of mullite and mullite-type materials include: high-temperature composites, aerospace materials, ballistic shielding for military applications and even non-linear optical materials. There are many uncertainties regarding the basic physical properties of mullite-type materials, particularly in terms of their high-pressure structural stability and mechanical behavior that are important to address for emerging applications of mullites as engineering materials. This work is the first reported comprehensive investigation of the high –pressure structural behavior of several different mullites …

Recent Research Progress For Non-Pt-Based Oxygen Reduction Reaction Electrocatalysts In Fuel Cell, Ping Song, Ming-Bo Ruan, Jing Liu, Guang-Jun Ran, Wei-Lin Xu

Journal of Electrochemistry

The expensive Pt-based catalyst suffers from its susceptibility to time-dependent drift, methanol crossover, and carbon monoxide (CO) deactivation, which will block the large-scale commercial application of fuel cells. It is, therefore, necessary to develop efficient, low-cost, highly stable non-precious metal oxygen reduction reaction (ORR) catalysts with high catalytic performance. Here, we will pay attention to the research progress of non-precious metal and heteroatom-doped (N, B, P, S, F) metal-free ORR catalysts. Importantly, we mainly focus on the work developed by Xu’s group with the Fe-based non-precious metal and F/NF-doped metal-free ORR catalysts. The purpose of these works is to improve …

Research Progress Of Mn-Based Lithium-Rich Cathode Materials For Li-Ion Batteries, Luo-Zeng Zhou, Qun-Jie Xu, Wei-Ping Tang, Xue Jin, Xiao-Lei Yuan

Journal of Electrochemistry

With rapid development of new energy industry like electric vehicles and energy storage station, these fields highly demand the next generation of high performance Li-ion battery systems with stronger energy density, higher power density, and longer cycling life. Lithium-rich Mn-based cathode materials, xLi₂MnO₃·(1-x)LiMO₂(M=Mn, Co, Ni...), have become the hot topic and drawn attentions of scholars worldwide because of their high reversible capacity exceeding 240 mAh·g^-1, excellent electrochemical properties, and low cost, which makes them most promising cathode material candidates for next Li-ion battery system. The cathode material Li[Li_0.2Mn_0.54Ni …

Preparation And Properties Of Binary Oxides CoXCr1-XO3/2 Electrocatalysts For Oxygen Evolution Reaction, Tai-Lai Yang, Wen-Yan Dong, Hui-Min Yang, Li Zhang, Zhen-Hai Liang

Journal of Electrochemistry

Binary metal mixed oxides of Co and Cr with nominal compositional formulas, Co_xCr_1-xO_3/2 (x=0, 0.2, 0.4, 0.6, 0.8 and 1.0), were obtained by thermal decomposition method. The morphologies, crystal forms and valence states of the catalyst powders were analyzed by SEM, XRD and XPS, respectively. And the electrochemical properties, overpotentials and stabilities of Co_xCr_1-xO_3/2 electrodes for oxygen evolution reaction (OER) in an alkaline solution were evaluated by linear sweep voltammetry (LSV), staircase voltammetry and chronoamperometry, respectively. The results indicated that the mixtures of Co₃O₄ and eskolaite-Cr_{2 …}

Synthesis And Electrochemical Properties Of Cnts/V2O5 Hollow Microspheres, Liang Hao, Lai-Fa Shen, Jie Wang, Jia-Jia Zhu, Xiao-Chen Zhao, Xiao-Gang Zhang

Journal of Electrochemistry

The carbon nanotubes/vanadium oxides (CNTs/V₂O₅) hollow microspheres (VOC) were prepared via solvothermal process. The effects of the ratio for CNTs to V₂O₅ on the morphologies, structures and electrochemical performances were systemically investigated. The results indicate that CNTs dramatically enhanced the rate performances of VOC composite electrodes. When the ratio of CNTs is 7.1%, the VOC composite electrode exhibited the best electrochemical performance, which delivered a specific capacitance of 346 F·g^-1 at 0.5 A·g^-1 and maintained 75% at 8 A·g^-1 in 5 mol L^-1 LiNO₃. A hybrid capacitor …

Electrochemical Performance Of Coal2O4-Coated Lini1/3Co1/3Mn1/3O2, Ji-Jun Cai, Wang-Jun Cui, Bing Li, Yang-Yang Yu, Jin-Bao Zhao

Journal of Electrochemistry

A method to improve the electrochemical performance of LiNi_1/3Co_1/3Mn_1/3O₂ for high voltage lithium-ion battery by CoAl₂O₄ coating was present in this work. The effects of CoAl₂O₄ coatings on the structure and electrochemical properties of LiNi1/3Co1/3Mn1/3O2 were investigated in detail. The results show that CoAl₂O₄ forms a thin layer of 8 nm on the surface of LiNi_1/3Co_1/3Mn_1/3O₂ without destroying the structure of the core material. The CoAl₂O₄-coated LiNi_1/3Co_1/3Mn_1/3O …

Porous Co3O4 Hollow Nanospheres Cathode Catalyst For High-Capacity And Long-Cycle Li-Air Batteries, Tong Liu, Na Li, Qing-Chao Liu, Xin-Bo Zhang

Journal of Electrochemistry

In this paper, a high specific surface area of porous Co3O4 hollow nanospheres was successfully synthesized via hydrothermal carbonization at 140 °C, followed by calcination using cobalt nitrate hexahydrate (Co(NO3)2·6H2O), hexamethylenetetramine (HMT), sucrose, and sodium citrate (Na3C6H5O7). The porous Co3O4 hollow nanospheres consisted of nanoparticles with high specific surface area of mesoporous structure, and could provide active reaction sites for OER and ORR. When used as lithium-air battery cathode catalyst, the Co3O4/Super P (SP) electrode exhibited excellent cycle performance, resulting in high capacity and long life of lithium-air batteries.

Electrodeposition Of Al-Mg Alloys From Acidic Alcl3-Emic-Mgcl2 Room Temperature Ionic Liquids, Rostomali M., P. Abbott Andrew, S. Ryder Karl

Journal of Electrochemistry

Electrodeposition of aluminium-magnesium alloys have been carried out onto platinum and copper cathodes from Lewis acidic aluminium(III) chloride-1-ethyl-3-methylimidazolium chloride ionic liquid containing magnesium(II) chloride by constant current and constant potential methods at room temperature. Magnesium content in the deposited alloy increases with increasing MgCl₂ concentration in the ionic liquid and with increasing cathodic current density. The influences of various experimental conditions on electrodeposition and the morphology of the electrodeposited layers have been investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectroscopy (EDAX). On increasing the deposition current densities the dense, bright, adherent …

Syntheses And Electrochemical Performances Of Li4Ti5O12 Anode Materials For Lithium Ion Battery, Yong-Long Zhang, Xue-Bu Hu, Yao-Qiong Wang, Dong-Hai Huang

Journal of Electrochemistry

Series of spinel lithium titanate (Li₄Ti₅O₁₂) materials were synthesized by one-step solid-state reaction using lithium acetate and TiO₂ as raw materials under different temperatures (750/800/850 °C) and atmospheres (N₂/air). The as-prepared Li₄Ti₅O₁₂ materials were investigated by thermogravimetric analysis, X-ray diffraction, scanning electron microscopy, cyclic voltammotry and charge-discharge test to analyze their crystal structures, microstructures and electrochemical performances. The results show that the Li₄Ti₅O₁₂（L-800N）material obtained at 800 °C under nitrogen atmosphere exhibited better electrochemical performance and smaller particle size. The initial …

A Platinum-Hydrogen Reference Micro-Electrode For All Vanadium Redox Flow Battery, Zhi-Bin Lin, Yan-Qing Dong, Ming-Sen Zheng, Quan-Feng Dong

Journal of Electrochemistry

A platinum-hydrogen reference micro-electrode was made with electroplating Pd on the surface of Pt wire and then coating anion membrane material. This reference electrode was built-in the porous electrode of the all vanadium redox flow batteries (VRFB), and monitored the charging /discharging and self-discharging of the VRFB. The results indicated that the capacity fading of VRFB occurred due to the graduate reduction of V(IV) active species in the electrolyte and the accumulation of V(V) in the positive electrode, leading to nonequilibrium of active species between the positive and negative electrodes.

Researches On In-Situ And Ex-Situ Characterization Techniques In Lithium Batteries, Wen-Jun Li, Jie-Yun Zheng, Lin Gu, Hong Li

Journal of Electrochemistry

Electrochemical performance of Lithium batteries is directly linked to interfacial transports, reactions and storing behaviors of electrons and ions at bulk-surface interfaces. It is extremely important to conduct evolution studies from atomic level to macro level in electron structures, crystal structures, microstructures and morphologies, chemical compositions and physical properties of battery materials at equilibrium and nonequilibrium in order to understand various structure-performance relations in lithium ion batteries. Advanced in-situ and ex-situ characterization techniques have been used widely to clarify scientific and technological problems in lithium batteries. This paper summarizes our efforts on battery researches using various experimental techniques, including in …

Electrochemical Conversion Reactions And Their Applications For Rechargeable Batteries, Ting Li, Han-Xi Yang

Journal of Electrochemistry

Electrochemical conversion reactions have received considerable interest as a new redox mechanism for constructing high capacity electrodes of rechargeable batteries. Without strict restrictions on the crystalline structure of the host lattice and the size of the associated ions, conversion reactions can take place in a variety of different metal compounds with different metal cations and deliver much higher reversible capacities through full utilization of all the oxidation states of the transition-metal compounds, opening up a new avenue for developing high capacity materials of rechargeable batteries. This paper briefly reviews the state of the art and challenges of conversion electrodes and …

Local Control Robotic Surgical Devices And Related Methods, Eric Markvicka, Tom Frederick, Jack Mondry, Joe Bartels, Shane Farritor

Department of Mechanical and Materials Engineering: Faculty Publications

The various robotic medical devices include robotic devices that are disposed within a body cavity and positioned using a support component disposed through an orifice or opening in the body cavity. Additional embodiments relate to devices having arms coupled to a device body wherein the device has a minimal profile such that the device can be easily inserted through smaller incisions in comparison to other devices without such a small profile. Further embodiments relate to methods of operating the above devices.

Fluids Dynamics & Heat Transfer Lab Design, Bruce Gerry

Thinking Matters Symposium Archive

This project consists of the designing, building, and creation of instruction manuals for several labs in fluids and heat transfer fields. Labs for these fields tend to be large and hard to simulate as physical models. This project will solve that problem by creating simulations: in solidworks. Not only will simulations in solidworks make some concepts possible to demonstrate but, it will also expose students to useful software that will be used in the workforce.

Intensity And Resolution Enhancement Of Local Regions For Object Detection And Tracking In Wide Area Surveillance, Evan Krieger, Vijayan K. Asari, Saibabu Arigela, Theus H. Aspiras

Electrical and Computer Engineering Faculty Publications

Object tracking in wide area motion imagery is a complex problem that consists of object detection and target tracking over time. This challenge can be solved by human analysts who naturally have the ability to keep track of an object in a scene. A computer vision solution for object tracking has the potential to be a much faster and efficient solution. However, a computer vision solution faces certain challenges that do not affect a human analyst. To overcome these challenges, a tracking process is proposed that is inspired by the known advantages of a human analyst.

First, the focus of …

A Microscopic Study On The Corrosion Fatigue Of Ultra-Fine Grained And Conventional Al–Mg Alloy, Mala M. Sharma, Josh D. Tomedi, Jeffery M. Parks

Faculty Journal Articles

The corrosion behavior of a nanocrystalline (NC)/ultrafine grained (UFG) Al–Mg based alloy was investigated and compared to its conventional counterpart 5083(H111). The corrosion fatigue (CF) was studied with respect to pit initiation, pit location and crack propagation as a function of environment. Scanning electron microscopy (SEM) with EDS was used to analyze the fracture surface of the failed specimen with respect to pitting characteristics, crack propagation and corrosion product. Load vs. cycles to failure was measured and S/N curves were generated for the UFG Al–Mg based alloy and the conventional counterpart 5083 in air and seawater.

An Operational Performance And Safety Comparison Of Roundabouts Vs. Traditional Intersections, Vincent Spahr

Honors Theses

As the modern roundabout becomes a more popular intersection alternative in the United States, the ability of the roundabout to effectively manage traffic and to do so safely is on the forefront of engineering concerns. Despite decades of international success and credibility, regions throughout the U.S. have been hesitant to implement roundabouts in place of more traditional intersections. This case study of a series of intersections in Dublin, OH assesses the operational performance of roundabouts as it compares to that of their stop-controlled and signalized counterparts and analyzes historical crash data to evaluate the safety of the various intersection types. …