Materials Science and Engineering Commons^™

Applications Of Block Copolymer Films In The Field Of Electrochemical Energy Systems, Jing-Ze Li, Guo-Guang Chen, Di Mei, Wei Zou, Jian-Wen Li, Motonori Komura, Tomokazu Iyoda

Journal of Electrochemistry

A new series of amphiphilic liquid crystalline block copolymer thin films,having normally aligned and highly ordered nanocylinder array,were functionalized as anisotropic ion conducting materials by selectively infiltration.These ion-active nanocylinders are coaxially aligned and hexagonally arranged in a large area,which might be used as novel types of electrolyte films for electrochemical energy systems such as lithium ion battery,fuel cell,etc.Since the ordered cylinders can carry on and store the ions,the block copolymer films can be utilized as the advanced template to fabricate the ordered array of nanoporous,nanoparticles,and nanowires for the potential application in lithium ion battery as three dimensional electrode materials.

Cobalt-Doped Todorokite Prepared By Refluxing At Atmospheric Pressure As Lithium-Ion Battery Cathode, Rui-Qi Li, Chun-Hua Song, Chao Xu, Li-Xing Tu, Guo-Hong Qiu, Fan Liu

Journal of Electrochemistry

Cobalt-doped todorokites were prepared by refluxing at atmospheric pressure,and then charactered by X-ray diffraction(XRD),thermogravimetry(TG) and the analysis of chemical compositions.These measurements showed that all of the refluxing products were single phase of todorokites and the structure formulas were Mg_xCo_yMnO_z·nH₂O,where 0.18 ≤ x ≤ 0.22,0 ≤ y ≤ 0.24,2.10 ≤ z ≤ 2.53,and 0.35 ≤ n ≤0.73.The electrochemical characteristics of cobalt-doped todorokites were examined as lithium insertion hosts for cathodes in rechargeable lithium batteries.The first discharge capacity of undoped todorokite electrode was 211 mAh/g and the discharge capacity became 37 mAh/g after 30 …

Fabrication And Characterization Of The Ni-Scsz Composite Anodes With A Lscm-Ceo2 Catalyst Layer In Thin Film Sofc, Yun-Yun Wang, Bo Huang, Xin-Jian Zhu, Wan-Qi Hu, Qing-Chun Yu

Journal of Electrochemistry

Solid oxide full cell(SOFC) running directly on hydrocarbon fuels has attracted much attention in recent years. In this paper, a dual-layer structure anode was fabricated by tape casting and screen printing method. The addition of a LSCM-CeO₂ catalyst layer to the supported anode surface yielded better performance in ethanol fuel. The maximum power density reached 710 and 669 mW/cm² at 850 ℃ running on hydrogen gas steam and ethanol steam,respectively. No significant degradation in performance has been observed after 216 h of cell testing when the Ni-ScSZ13 anode was exposed to the ethanol steam at 700 ℃. Very …

Study Of Electrodes Modified With Hybrid Copper Cobalt Hexacyanoferrate-Mwcnts Composites, Shan Jiang, Yun Zhang, Xiao-Yan Wang, Xiao-Fei Yao

Journal of Electrochemistry

The hybrid modified electrodes were obtained by electrochemical deposition of copper-cobalt hexacyanoferrate(CuCoHCF) /multi-walled carbon nanotubes(MWCNTs) on the surface of glassy carbon electrode.The effects of the amount of MWCNTs and composition of electrolyte on the properties of modified electrode had been researched.The copper cobalt hexacyanoferrate-MWCNTs modified electrodes show excellent electrochemical properties compared with that modified only copper-cobalt hexacyanoferrate.The CuCoHCF-MWCNTs/GCE exhibits obvious electrocatalytic activity towards oxidation of hydrogen peroxide.The oxidation peak current increased linearly with the concentration of hydrogen peroxide in the range of 3.16 × 10^-5 ～ 2.92 × 10^-3 mol· L^-1.The linear equation is given up …

Electrochemical Properties Of Ni(Oh)2 Doped By Nio, Fei-Biao Chen, Bo-Rong Wu, Wei-Feng An, Zhao-Jun Yang, Feng Wu, Shi Chen

Journal of Electrochemistry

The Ni(OH)₂ cathode material of MH/Ni was doped by NiO,which behaves as a capacitor and can improve the charge-discharge rate capacity of Ni(OH)₂.The electrochemical properties of Ni(OH)₂ was characterized by charge-discharge curves and cyclic voltammetry.The results showed that the material had the best discharge property when doped by 5% NiO,and the discharge specific capacity could reach 310.1 mAh/g at 0.2 C rate and remianed 79.5% at 3 C rate.The difference oxidation and reduction potentials between the of the battery was 164 mV when the Ni(OH)₂ was doped by 5% NiO,which showed a good cyclic property.

Synthesis Of High-Performance Lini1/3Co1/3Mn1/3O2 Cathode Materials Via Azeotropic Distillation Method, Sheng-An Xia, Li-Xia Yuan, Ze Yang, Zhao-Hui Wang, Yun-Hui Huang, Shuang Li, Wu-Xing Zhang, Ya-Bin Meng, Wei-Gong Zheng

Journal of Electrochemistry

Layered LiNi_1/3Co_1/3Mn_1/3O₂ is one of the most promising alternative materials for LiCoO₂ in lithium ion batteries due to its low cost,large capacity and excellent cyclability.In this paper,LiNi_1/3Co_1/3Mn_1/3O₂ was synthesized via azeotropic distillation method with isobutyl alcohol as an azeotropic agent.The structure and surface morphology were characterized by X-ray diffraction(XRD) and scanning electron microscope(SEM),respectively.The as-prepared LiNi_1/3Co_1/3Mn_1/3O₂ shows a layered α-NaFeO₂ structure;the particles are small and uniformly distributed.As compared with the sample prepared by traditional method,the present cathode material …

Electrosynthesis Of P-Aminobenzenearsenic Acid, Chun-An Ma, Qin-An Zheng, Qiang Zhou, Ying-Hua Xu

Journal of Electrochemistry

The electrochemical reduction of p-nitrophenyl arsonit acid to p-aminobenzenearsenic acid was studied using controlled-current electrolysis.The results showed that the yield of p-aminobenzenearsenic acid was determinated by the following factors:the concentrations of sulphuric acid,the amount of additive,temperature and the concentrations of p-nitrophenyl arsenic acid.The optimum electrolytic conditions were obtained to be is 10% H₂SO₄,1% NaCl,80 ℃,25 g/350 mL p-nitrophenyl arsenic acid and 10 A·dm^-2.The yield of arsanilic acid could be reached 64.7% under the optimum electrolytic conditions.

The Synthesise Of Electron-Conducting Redox Hydrogel And Its Application In Microbial Fuel Cell, Kai-Peng Wang, Sheng-Li Chen

Journal of Electrochemistry

Efficient electron transfer between the microbe and the anode is key for the electricity generation in Microbial fuel cell(MFC).Through the modification of anode,the rate of electron transfer can be accelerated,therefore the performance of MFC can be enhanced.In this paper,we report the synthesis of a type of electronconducting and bio-compatible redox hydrogel and its application.The hydrogel consists of poly(4-vinylpyridine) as backbone and neutral red as the redox center.By immobiliazing neutral red on the backbone through covalent bond,the secondary contamination due to the soluble redox mediator to external environment can be prevented.MFCs using the hydrogel-modified carbon anode significantly exhibit shorter acclimation period,and …

Time-Temperature Curing Relationship Of An Adhesive Binder With Rice Straw, Kevin Ka-Wan Ng

Master's Theses

Rice straw is a global and proliferate agricultural waste whose production grossly outstrips viable uses. Current disposal methods are not sustainable, and more convenient methods – such as incineration – exude poor environmental stewardship. Although the direct use of straw bales in building construction presents a practical and sustainable alternative, engineering challenges associated with using it prevent its wide adoption. The Stak Block – a composite formed from compressed rice straw and a heat-cured adhesive – may overcome challenges associated with straw bale building. However, the times and temperatures needed to cure the binder with straw are not well understood. …

Effect Of Friction Stir Processing On Fatigue Behavior Of An Investment Cast Al-7si-0.6 Mg Alloy, S. Jana, Rajiv S. Mishra, J. B. Baumann, G. Grant

Materials Science and Engineering Faculty Research & Creative Works

Cast aluminum alloys in general show poor fatigue performance due to the presence of defects. Friction stir processing (FSP) can be used as a tool to enhance the mechanical properties of cast alloys by eliminating such defects. in the present study FSP led to a five times improvement in fatigue life of an investment cast Al-7Si-0.6 Mg hypoeutectic alloy. the reason for such an enhancement was linked to the closure of casting porosities, which acted as crack nucleation sites in the as cast condition. Porosities acted as notches in the as cast alloy and led to an order of magnitude …

Synthesis And Characterization Of Metal Oxide Semiconductors For Photoelectrochemical Hydrogen Production, Sudhakar Shet

Dissertations

The goal of this thesis is to investigate the properties of metal-oxide thin films on fluorine-doped tin oxide (FTO)-coated glass substrates, prepared by using radio- frequency (RF) reactive magnetron sputtering for photoelectrochemical (PEC) applications. Metal-oxide thin films as a photoelectrode are of special interest for PEC systems to produce hydrogen in an aqueous solution by solar energy due to their low cost and potential stability.

The following list represents some of the accomplishments and results of this work:

• Narrowing of N-incorporated ZnO (ZnO:N) was achieved by reactive sputtering in a O₂/N₂ mixture ambient, and ZnO:N films with …

Modeling The Combined Effect Of Surface Roughness And Shear Rate On Slip Flow Of Simple Fluids, Nikolai V. Priezjev, Anoosheh Niavarani

Mechanical and Materials Engineering Faculty Publications

Molecular dynamics (MD) and continuum simulations are carried out to investigate the influence of shear rate and surface roughness on slip flow of a Newtonian fluid. For weak wall-fluid interaction energy, the nonlinear shear-rate dependence of the intrinsic slip length in the flow over an atomically flat surface is computed by MD simulations. We describe laminar flow away from a curved boundary by means of the effective slip length defined with respect to the mean height of the surface roughness. Both the magnitude of the effective slip length and the slope of its rate-dependence are significantly reduced in the presence …

Reaction Sintered Zirconium Carbide/Tungsten Composite Bodies And A Method For Producing The Same, Shi C. Zhang, Greg Hilmas, William Fahrenholtz

Materials Science and Engineering Faculty Research & Creative Works

A method of sintering a composite body characterized by a transition metal carbide phase (such as a ZrC phase) substantially evenly distributed in a second, typically refractory, transition metal (such as W) matrix at ambient pressures, including blending a first predetermined amount of first transition metal oxide powder (such as ZrO₂) with a second predetermined amount of second transition metal carbide powder (such as WC powder). Next the blended powders are mixed to yield a substantially homogeneous powder mixture and a portion of the substantially homogeneous powder mixture is formed into a green body. The body is fired …

Multiscale Transformation Field Analysis Of Progressive Damage In Fibrous Laminates, Yehia Bahei-El-Din, Ritesh Khire, Prabhat Hajela

Centre for Advanced Materials

As part of an ongoing effort to model uncertainty propagation across multiple scales in fibrous laminates, this paper presents a deterministic transformation field analysis for modeling damage progression under membrane forces and bending moments. In this approach, equivalent eigenstresses are computed in the phases and/or plies such that their respective stress components that satisfy the underlying failure criteria are reduced to zero. Superposition of the solutions found for the undamaged laminate under applied loads and under the eigenstress field provide the entire response. Failure criteria are based on stress averages in the fiber and matrix. Damage mechanisms considered are frictional …

Modified Sandwich Structures For Improved Impact Resistance Of Wind Turbine Blades, Yehia Bahei-El-Din, Mostafa Shazly, I. El-Habbal, Y. Elbahy

Centre for Advanced Materials

Wind turbine blades are susceptible to damage due to fatigue as well as impact by flying objects and parts broken off failed blades of nearby wind towers. Localized, permanent compression of the foam core and delamination of the fibrous composite face sheets are typical damage modes and can lead to progressive structural failure. Sandwich structures modified by inclusion of flexible polyurethane (PU) layers within the cross section are examined under both impact and dynamic loads. Finite element models of sandwich structures with conventional and modified designs show that sandwich designs modified with PU interlayes exhibit reduced foam core crushing and …

Microstructural Effects During Chemical Mechanical Planarization Of Copper, Patrick J. Andersen, Mariela N. Bentancur, Amy J. Moll, Megan Frary

Materials Science and Engineering Faculty Publications and Presentations

Novel die-stacking schema using through-wafer interconnects require vias to be filled with electroplated Cu, resulting in thick copper films, and requiring an aggressive first-step CMP. This work investigates the effects of microstructure on CMP of copper films, which are not presently well understood. Bulk and local removal rates were investigated for several different microstructures. Surface orientation maps were created and the orientations of individual grains were correlated with topographical data to elucidate local removal behavior. Cu removal depends on the details of the microstructure, and certain microstructures allowed for either faster or more uniform removal of thick Cu films.

Oscillatory And Monotonic Modes Of Long-Wave Marangoni Convection In A Thin Film, Sergey Shklyaev, Mikhail Khenner, Alexei Alabuzhev

Mathematics Faculty Publications

We study long-wave Marangoni convection in a layer heated from below. Using the scaling k=O Bi, where k is the wave number and Bi is the Biot number, we derive a set of amplitude equations. Analysis of this set shows presence of monotonic and oscillatory modes of instability. Oscillatory mode has not been previously found for such direction of heating. Studies of weakly nonlinear dynamics demonstrate that stable steady and oscillatory patterns can be found near the stability threshold.

Application Of Self-Determination And Self-Regulation Theories To Course Design: Planting The Seeds For Adaptive Expertise, Linda Vanasupa, Jonathan Stolk, Trevor Harding

Materials Engineering

The paper is grounded in the premise that learning occurs within a dynamic system of social and ecological interactions in the learning environment. Our intent is to open the conversation about hose ac, as engineering educators, design effective learning experiences for this dynamic system, particularly in light of the deeply ethical, adaptive expertise required of today's graduates. Drawing from two well-researched theories of psychological development (self-determination and self-regulation), we assert that fostering the engagement and positive growth required for adaptive expertise necessitates a holistic educational approach. This approach requires us to consider both the psychological needs of the learner, and …

The Systemic Correlation Between Mental Models And Sustainable Design: Implications For Engineering Educators, Linda Vanasupa, Roger Burton, Jonathan Stolk, Julie B. Zimmerman, Larry J. Leifer, Paul T. Anastas

Materials Engineering

Many studies have illuminated our understanding of the kinds of competencies and behaviors exhibited by effective designers. Against the backdrop of global challenges made more urgent by unintentional negative impacts of engineered products and systems, however, we are left to deduce that our ways of educating engineering designers is fundamentally flawed. We assert that one can trace the cause of our collective, unintended negative consequences to the mental models of reality that we consciously or unconsciously carry. In this paper, we present the case for developing awareness and facility with mental models. We also suggest an alternate mental model as …

Oscillatory And Monotonic Modes Of Long-Wave Marangoni Convection In A Thin Film, Sergey Shklyaev, Mikhail Khenner, Alexei Alabuzhev

Mathematics Faculty Publications

We study long-wave Marangoni convection in a layer heated from below. Using the scaling k=O Bi, where k is the wave number and Bi is the Biot number, we derive a set of amplitude equations. Analysis of this set shows presence of monotonic and oscillatory modes of instability. Oscillatory mode has not been previously found for such direction of heating. Studies of weakly nonlinear dynamics demonstrate that stable steady and oscillatory patterns can be found near the stability threshold.