Engineering Science and Materials Commons^™

Rehabilitation And Exercise Machine, Judith M. Burnfield, Yu Shu, Thad W. Buster, Carl Nelson

Department of Mechanical and Materials Engineering: Faculty Publications

An improved rehabilitation and exercise machine is provided which allows a person with physical limitations, disabilities or chronic conditions to use the machine in order to rehabilitate their muscles, improve joint flexibility, and enhance cardiovascular fitness.

Laboratory And Field Evaluation Of Two Warm-Mix Additives In Connecticut And Validation Of An Alternative Moisture Susceptibility Test, Alexander K. Bernier

Master's Theses

The first official state Warm-Mix Asphalt (WMA) pavement project in Connecticut was constructed between July 20th and 22nd, 2010 and it involved three experimental sections, i.e. one section with a conventional HMA (control section) and two WMA sections with different technologies, wax and foamed asphalt. All three sections are located on Route 70 in central Connecticut. The materials were collected in loose form and reheated and compacted in laboratory conditions (laboratory fabricated specimens). This paper discusses the effect of mix type on the results from several tests conducted in the laboratory, such as Semi-Circular Bending, Hamburg Wheel Tracking, Indirect Tensile, …

Molecular Dynamics Study Of Diffusion Of O2 Penetrates In Uncrosslinked Polydimethysiloxane (Pdms), Crosslinked Pdms, And Pdms-Based Nanocomposites, Varun Ullal

Graduate Theses and Dissertations

Molecular dynamics simulations are used to study diffusion of O₂ molecules in pure polydimethysiloxane (PDMS), crosslinked PDMS, and PDMS-based nanocomposites. The PDMS chains and penetrates are modeled using a hybrid interatomic potential which treats the Si-O atoms along the chain backbone explicitly while coarse-graining the methyl side groups and penetrates. By tracking the diffusion of penetrates in the system and subsequently computing their mean-squared displacement, diffusion coefficients are obtained. In pure PDMS models of varying molecular weight, diffusivity of the O₂2 penetrates is found to have an inverse relationship with chain length. Simulation models with longer chains …

Analytic And Finite Element Solutions Of The Power-Law Euler-Bernoulli Beams, Dongming Wei, Yu Liu

Mathematics Faculty Publications

In this paper, we use Hermite cubic finite elements to approximate the solutions

of a nonlinear Euler-Bernoulli beam equation. The equation is derived

from Hollomon’s generalized Hooke’s law for work hardening materials with

the assumptions of the Euler-Bernoulli beam theory. The Ritz-Galerkin finite

element procedure is used to form a finite dimensional nonlinear program

problem, and a nonlinear conjugate gradient scheme is implemented to find

the minimizer of the Lagrangian. Convergence of the finite element approximations

is analyzed and some error estimates are presented. A Matlab finite

element code is developed to provide numerical solutions to the beam equation.

Some …

Shock And Vibration Isolation System For Ambulatory And Litter Patients In Ground And Air Medical Transport, Mohamad R. Hachem

UNLV Theses, Dissertations, Professional Papers, and Capstones

This project explored the effectiveness of seat and litter air bladder technologies in reducing patient exposure to whole body shock and vibration during ground borne and airborne medical transport. Several seat and litter air bladder configurations were examined during field tests in a U.S. Army RG-33 MRAP ambulance and a U.S. Army HH-60M Black Hawk helicopter. The MRAP field tests were conducted at Ft. Detrick, Maryland. The Black Hawk field tests were conducted at Ft. Rucker, Alabama.

During the field tests, tri-axial vibration signals were recorded on a 16-channel CoCo90 Data Logger/Frequency Analyzer and then post processed in the laboratory …

The Effect Of Full Body Versus Partial Body Graphic Labeling On Beverage Packaging, Toni Gomes

All Theses

Through the collection of quantitative and qualitative data, the shelf presence of
full body graphic labels versus partial body graphic labels on plastic beverage bottles was
examined and evaluated. Eye tracking was used to collect phenomenological data atop
the stimuli, while a shopping checklist was used to collect purchase preference. A postexperiment
survey was also conducted in order to gather qualitative data regarding
possible purchase influences.
The experiment was a 2 (label size) x 6 (beverage flavor) x 2 (age group) study,
conducted with 28 participants in a consumer retail environment using mobile eye
tracking technology. The goal of this …

Statistical Analysis Of The Stress-Energy Methodology Applied To Cushion Curve Determination, Kendalyn Paulin

All Theses

The stress-energy method is a proposed enhancement to ASTM D1596 that reduces all drop height, thickness and static load combinations into a single equation that can be used to generate any reasonable cushion curve for a particular material. There remains a question as to how accurate the stress-energy method can predict acceleration values and whether it is statistically comparable to ASTM D1596. There are three phases to this research that attempt to determine the accuracy of the stress-energy method: gathering data using the stress-energy method and analyzing the goodness of fit of the stress-energy equation, predicting a cushion curve and …

NaXMYFe(Cn)6(M=Fe, Co, Ni): A New Class Of Cathode Materials For Sodium Ion Batteries, Jiang-Feng Qian, Min Zhou, Yu-Liang Cao, Han-Xi Yang

Journal of Electrochemistry

Three types of Prussian blue compounds, Na_xM_yFe(CN)₆ (M = Fe, Co, Ni), were prepared simply by solution precipitation method and tested as cathode materials for sodium-ion batteries. X-ray diffraction and SEM measurements demonstrated that the prepared materials, namely, NaFeFe(CN)₆, Na₂CoFe(CN)₆, and Na₂NiFe(CN)₆, exhibited a perfect cubic structure with a particle size of several tens nanometers. Cyclic voltammetric and galvanostatic cycling tests revealed very different electrochemical behaviors of these three materials. The specific capacities of NaFeFe(CN)₆ and Na₂CoFe(CN)₆ could reach 113 mAh·g …

Preparation And Electrochemical Performance Of Mo-Doped Li3V2(Po4)3/C Cathode Materials, Zhi-Yuan Tang, Wei Yuan, Ji Yan, Wen-Feng Mao, Li Ma

Journal of Electrochemistry

The molybdenum-doped Li₃V_2-xMo_x(PO₄)_3/C (x = 0.01, 0.02 and 0.03) cathode materials were prepared with a sol-gel method by using Li₂CO₃, NH₄H₂PO₄, V₂O₅ and MoO₃ as raw materials, and citric acid as both chelating reagent and carbon source. The X-ray diffraction (XRD) analyses showed that the crystal structure of as-prepared samples is monoclinic with space group P2₁/n. Scanning electron microscopy (SEM) observations indicated the uniform morphology for Li₃Mo_0.02V_1.98(PO₄) …

Synthesis Of Lini0.5Co0.2Mn0.3O2 For Lithium Ion Batteries And The Mechanism Of Capacity Fading At High Temperature, Wen Liu, Miao Wang, Ji-Tao Chen, Xin-Xiang Zhang, Heng-Hui Zhou

Journal of Electrochemistry

The Ni-rich cathode materials, LiNi_0.5Co_0.2Mn_0.3O₂, have been synthesized by Co-precipitation and high-temperature solid-phase sintering method. Constant current charge-discharge tests showed high discharge capacity of 179.2 mAh·g^-1 in the 3.0~4.4 V at 0.2C. However, at 55 °C the LiNi_0.5Co_0.2Mn_0.3O₂ experienced the dramatic capacity fading after 100 charge-discharge cycles. Electrochemical Impedance Spectroscopy, X-Ray Photoelectron Spectroscopy, Atomic Emission Spectroscopy have been employed to study the capacity fading mechanism of LiNi_0.5Co_0.2Mn_0.3O₂ cycled at high temperature in range of high-voltage charge and …

Synthesis And Electrochemical Properties Of Lifeso4F/Graphene Composite As Cathode Material For Lithium-Ion Batteries, Wei Guo, Ya-Xia Yin, Li-Jun Wan, Yu-Guo Guo

Journal of Electrochemistry

The LiFeSO₄F was successfully synthesized from the reactions of FeSO₄∙xH₂O (x=1, 4, 7) with LiF in tetraethylene glycol media through a facile low temperature method. The structures and microscopic features of the products were characterized by XRD, SEM and TEM. TGA result shows the good thermal stability of the as-prepared LiFeSO₄F. No diffraction peaks of the FeSO₄ are observed in the as-prepared products with the starting material of either FeSO₄∙4H₂O or FeSO₄∙7H₂O, which should be ascribed to delaying the release of H_{2 …}

Ethanol Electrooxidation On Pt/Mo2/Cnts Catalysts, Yu-Long Cheng, Jie Sun, Ji-Gang Li, Li-Gong Zhang, Tian Zhou, Geng Chang, Zhong-Chao Dong

Journal of Electrochemistry

The ethanol electrooxidation behaviors on Pt/MO₂/CNTs（M=Sn, Ti, Ce）and Pt/CNTs catalysts in H₂SO₄ solutions were researched by cyclic voltammetry. It has revealed that the catalysts with the addition of metal oxides presented higher electrooxidation activity for ethanol, in particular, the Pt/CeO₂/CNTs catalyst showed the best activity for ethanol electrooxidation intermediate. The Pt/SnO₂/CNTs catalyst demonstrated the best ethanol electrooxidation activity when considering the synthetic effects of such parameters as the onset oxidation potential, peak current densities and total oxidation area.

Electrochemical Performances Of Carbon-Coated Na2Ti6O13 Nanotubes, Guo-Ran Li, Shuai Sun, Xue-Ping Gao

Journal of Electrochemistry

With rutile TiO₂ and NaOH as starting materials, the Na₂Ti₆O₁₃ nanotubes were prepared by a hydrothermal reaction. The carbon-coated Na₂Ti₆O₁₃ nanotubes were obtained by treating the Na₂Ti₆O₁₃ nanotubes for 4 h in glucose aqueous solutions containing 0.1 mol·L^-1 NaOH. The as-prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microcopy (TEM). The results showed that the dimensions of carbon-coated Na₂Ti₆O₁₃ nanotubes were 14 ~ 19 nm of outer diameter, 2 ~ 5 …

Synthesis And Electrochemical Properties Of Yttrium-Doped Lini0.49Mn1.49Y0.02O4, Xian-Wen Zhang, Zheng-Xi Zhang, Li Yang, Shao-Hua Fang, Long Qu

Journal of Electrochemistry

The LiNi_0.49Mn_1.49Y_0.02O₄ cathode material was synthesized using the citric acid-assisted sol-gel method by partial substitutions of Ni and Mn with Y in the LiNi_0.5Mn_1.5O₄ material. The influences of Y doping on the structure and electrochemical properties were investigated by means of X-ray diffraction, cyclic voltammetry, galvanostatic charge/discharge tests and AC impedance spectroscopy. The results showed that the introduction of Y into the LiNi_0.5Mn_1.5O₄ greatly improved the cycle performance and rate capability. When the charge and discharge current was 1 C in the potential …

Catalytic Activities Of Electrochemically Dealloyed Pt(Pd)-Cu Catalysts For Oxygen Reduction Reaction, Rui-Zhi Yang, Strasser Peter, Toney Michael

Journal of Electrochemistry

The electrochemically dealloyed Pt(Pd)-Cu catalysts were prepared by electrochemical dealloying of Cu₃Pt(Pd) and their catalytic activities toward oxygen reduction reaction (ORR) were studied in 0.1 mol·L^-1 HClO₄ . solutions. The structural features of the dealloyed Pt(Pd)-Cu were revealed by synchrotron-based anomalous X-ray diffraction (AXRD) and surface X-ray scattering (SXS) at an atomic scale. We established a relationship between the structure and the catalytic activity by comparing the ORR activity and the structure of dealloyed Cu₃Pt nanoparticles with similarly dealloyed Cu₃Pt thin films and Cu₃Pt(111). The enhancement in the activity of …

Template-Free Synthesis Of Porous Nio Hierarchical Structure For High Performance Supercapacitors, Yun Huang, Zhong Wu, Xin-Bo Zhang

Journal of Electrochemistry

A facile and template-free hydrothermal method is proposed to successfully synthesize porous NiO hierarchical structure, which is found to be assembled from ultrathin NiO nanosheets. As for electrochemical pseudocapacitor application, the obtained material exhibits not only high specific capacitances of 435 F·g^-1 at 20 mV·s^-1 and 367 F·g^-1 at 10 A·g^-1, but also holds a good electrochemical stability over 1000 cycles at a current rate of 20 mV·s^-1. These results suggest that the hierarchical structured porous NiO is a promising supercapacitor electrode material.

Electrochemical Preparation Of Nanostructural Pt-Ni And Pd-Ni Films For Ethanol Electro-Oxidation, Chen-Zhong Yao, Hui-Xuan Ma, Bo-Hui Wei

Journal of Electrochemistry

The Pt-Ni and Pd-Ni films were successfully prepared on Ti substrates by electrodeposition method. The porous Pt-Ni nanoflakes appeared to be uniform with the thickness of the slices about 10 ~ 20 nm. The porous Pd-Ni nanoparticles with a flower shape appeared to be uniform with the diameters of 50 ~ 60 nm. The XRD patterns also indicated that the Pd-Ni and Pt-Ni nanostructures have the poor crystallinity. The onset potentials of ethanol oxidation were negatively shifted to –0.74 V on Pt-Ni electrodes and –0.71 V on Pd-Ni electrodes, respectively. Addition of Ni could enhance catalytic activities and antitoxic properties …

Electrochemical Reduction Of Co2 On Sn/Cu Electrodes, Chen-Chen Zhao, Jian-Wei Guo, Li Wang, Xiang-Ming He, Cheng Wang, Zhi-Xiang Liu

Journal of Electrochemistry

The Sn/Cu electrodes were prepared by electroplating method and their morphologies under different galvanization current densities were determined by SEM. In alkali, the effects of Sn/Cu electrodes on the activities towards hydrogen evolution and electrochemical reduction of CO₂ were investigated in alkaline solutions using a three-electrode system. These results indicated that the Sn/Cu electrodes prepared at 10 mA/cm² and 15 mA/cm² showed good activities, while that prepared at 15 mA/cm² was even better in activities. The synergetic structure of the Sn/Cu electrode to be beneficial to electrochemical reduction of CO₂ has been pointed out.

Electrochemical Properties Of The Keggin-Type Lacunary Heteropolysilicate Anion And Its Eectrocatalysis For H2O2 Reduction, Xi-Long Liu, Chun-Yan Wu, Fang Zhou, Hong-Sheng Liu, Ying-Jie Hua, Chong-Tai Wang, Xiao-Yang Liu

Journal of Electrochemistry

Electrochemical properties of the Keggin-type lacunary heteropolysilicate anion SiW₁₁O₃₉^8- (SiW₁₁) and its indirect electrocatalysis for H₂O₂ reduction in the supporting electrolyte containing 0.1 mol·L^-1 NaHSO₄ and Na₂SO₄ solutions were investigated using cyclic voltammetry, square wave voltammetry and alternating current impedance spectroscopy. Experimental results indicated that SiW₁₁ showed two pairs of reversible redox waves on the glassy carbon (GC) electrode in an acidic solution. The electron transfer number corresponding to the two pairs of waves was one, and the proton transfer number involved was two during …

Corrosion Inhibition Of 316l Steel Using Sodium Diethyl Dithiocarbamate Solution In Simulated Crude Oil, Xiao-Guang Ren, Jie Yang

Journal of Electrochemistry

The corrosion inhibition behaviors of 316L steel using the sodium diethyl dithiocarbamate (SDDTC) compound in the crude simulation solution were studied in the absence and presence of zinc sulfate or sodium chromate with different compositions. Experiment resultss showed that in the environments of highly acidic and high concentrations of chloride ions the SDDTC compound could well inhibit the corrosion of 316L steel. The good synergic effects on the corrosion inhibition of 316L steel by additions of either zinc sulfate or sodium chromate into SDDTC compound were indicated in this study, which is of great significance and importance in practical applications.