Materials Science and Engineering Commons^™

Synthesis By Complexation Processes And Characterization Of Lini0.8Co0.2O2 Cathode Materials, Jing Liu, Zhao-Yin Wen, Zhong-Hua Gu, Xiu-Jian Zhu, Zu-Xiang Lin

Journal of Electrochemistry

The layered LiNi_0.8Co_0.2O₂ compound, which has been of great interest for lithium ion batteries, was prepared at low temperatures by calcining a complex precursor at different temperatures. The physical properties of the synthesized cathode materials were discussed in the light of structural (XRD). The charge and discharge cycling of the cells containing the synthesized oxide as the positive electrode in conjunction with lithium metals and employing a non-aqueous electrolyte showed that LiNi_0.8Co_0.2O₂ treated at 900 ℃ exhibited excellent performances. The first discharge capacity of LLiNi_0.8Co_0.2O_{2 …}

Investigations Of Smooth Function Of Polyethylene Glycol Surfactants On The Electrolessly Deposited Silver Film, Hao Tong, Zhi-Qing Qiao, Fen-Ning Jing, Meng-Ke Li, Chun-Ming Wang

Journal of Electrochemistry

Some non-ionic surfactants of Polyethylene Glycol 2000, 6000 and 20000 were used to estimate the smooth affection on the electrolessly deposited silver film. The adsorption state of the surfactants about Si/solution interface was investigated by using open circuit potential-time technology (Opt). As comparative experiments, the atomic force microscopy (AFM) was also performed to study the surface smooth effection of the surfactants. It was found that with the increasing of the carbon chain in the surfactants, the smooth effection is getting great. PEG 20000 showed the best smooth function.

Electroreduction Of Cd(Ⅱ) In Dmso And Complexation Of Cd(Ⅱ) With Coumarin Derivates, Ji-Guo Song, Hua-Can Song, Qi-Qin Yang, Yi-Wen Chen, Zun-Le Xu

Journal of Electrochemistry

Cadmium p-toluenesulfonate was synthesized and tested electrochemically for the first time. This salt can lose all the hydrated water easily and the dehydrated salt do not deliquesce in the air.Hence,the cadmium p-toluenesulfonate is suitable for the electrochemical studies in organic solvents.When the Cd(Ⅱ) reduced on Pt electrode in Cd(p-CH₃C₆H₄SO₃)₂+TBAP+DMSO, underpotential deposition of cadmium occurred at first, and then cadmium deposited. 4-Methyl-7-hydroxylcoumarin and 3-aminocoumarin coordinate with Cd(Ⅱ) respectively, as a result the reductive potentials of Cd(Ⅱ) moved to the negative direction.

Experimental Investigation Of Steel Corrosion In Lead Bismuth Eutectic (Lbe): Characterization, Species Identification, And Chemical Reactions, John Farley, Dale L. Perry, Allen L. Johnson

Transmutation Sciences Materials (TRP)

The goal of the present research is to achieve a basic understanding of corrosion of steels by Lead Bismuth Eutectic (LBE). Liquid LBE is under consideration in the transmuter as both a spallation target and as a blanket coolant. There have been previous studies of LBE, especially by the Russians, who have over 80 reactor-years experience with LBE coolant in their Alpha-class submarine reactors. The Russians found that the presence of small amounts (ppm) of oxygen in the LBE significantly reduced corrosion. However, a fundamental understanding and verification of its role in the corrosion of steels is still very incomplete. …

Compositions And Methods For Wood Preservation, Peter Laks, Patricia Heiden

Michigan Tech Patents

The invention provides a method for incorporating biocides into wood or a wood product. The method comprises incorporating an additive into a nanoparticle, applying the nanoparticle to wood or a wood particle and applying sufficient pressure to force the nanoparticle to penetrate the wood or wood particle.

A Feasibility Study Of A Surface Modification Method For Polyolefin Plastics Formed By Injection Molding, David Brian Naughton

Master's Theses and Doctoral Dissertations

Polyolefin plastic (i.e. polypropylene, polyethylene, thermoplastic olefin i.e. TPO and blends) articles formed by injection molding have been found to have many useful applications. Many costly and/or hazardous methods are employed to increase the surface energy to a level that promotes the ability of a coating or adhesive to make intimate contact and thereby bond to the molded surface. The method described herein refers to a process that could eliminate the need for a post molding process such as solvent or waterborne adhesion promoting primers or expensive, hazardous surface treatment equipment by modifying the plastic surface during the injection molding …

Electron Microscopy Studies On Platinum-Ceramics Nanocomposites Synthesized By Spray Process, X.-D. Zhou

Materials Science and Engineering Faculty Research & Creative Works

The platinum-ceramics nanocomposites synthesized by spray process were discussed using electron microscopy. It was found that the nanocomposites of Pt-ceramics were synthesized by spray process with a controllable distribution of Pt primary particles. the analysis showed that the nanometer Pt primary particles encapsulating YSZ nanocomposites were derived when ethanol was used as solvent.

Out-Of-Plane Exchange Coupling Between Epitaxial Ni(50 Å) And Nio(600 Å) Bilayers, Z.Y. Liu, Shireen Adenwalla

Materials Research Science and Engineering Center: Faculty Publications

We have investigated the exchange coupling between an epitaxial Ni (50 Å) film with an out-of-plane magnetic easy axis and a NiO (600 Å) film by polar magneto-optic Kerr-effect measurements. The temperature dependences of exchange field H_E for both as-deposited and field-cooled states exhibit the same blocking temperature T_B~130 °C. The exchange field H_E for the field-cooled state is lower than that for the as-deposited state. The hard-axis in-plane loop shows a much smaller value of H_E. No coercivity enhancement is observed. The data are suggestive of linear coupling across the ferromagnet/antiferromagnet interface.

Corrosion Of Steel By Lead Bismuth Eutectic: Quarterly Report November- December 2002 January 2003, John Farley

Transmutation Sciences Materials (TRP)

We continue to get valuable data from sputter depth profiling of steel samples. We meet weekly to discuss progress. We took depth-profiling data on D9 steel that had been exposed to LBE. This the first time we have examined this type of steel. This is important because it will enable us to separate out two effects and determine their effect on corrosion: composition of the steel vs surface preparation.

We started to plan a small experiments using a crucible of heated LBE, with the research program to be conducted at UNLV, on basic aspects of corrosion in this system. The …

In Situ Laser Etch-Depth Monitoring Of The Deep Reactive Ion Etching Process, Yuki Imura

Theses

A laser-based method for measuring feature thickness during the deep reactive ion etching process is investigated. Interference occurs between laser beam reflections from the mask surface, the mask/silicon interface, and the exposed silicon surface of a process wafer. Information from this interference signal allows the etch process to be characterized. Three methods are investigated: laser-on-SiO₂, laser-on-photoresist, and laser-on-both SiO₂ and silicon at a mask edge.

The measured data from these experiments are found to be in good agreement with theoretical calculations. Differences in reflected beam amplitude and interference fringe frequency represent well the differences SiO₂ and …

Characterization And Corrosion Of Bcc-Tantalum Coating Deposited On Aluminum And Steel Substrate By Dc Magnetron Sputtering, Chirag Joshi

Theses

Tantalum is one of the most versatile highly refractory corrosion-resistant metals. Tantalum coating can be used as an effective corrosion barrier if it is continuous, free from defects and it adheres well to the substrate. A DC magnetron sputtering technique was used to deposit tantalum on aluminum and steel. X-ray diffraction measurements revealed that the tantalum films produced by sputtering had two crystallographic structures: a body centered cubic α-phase and a metastable tetragonal β-phase. Tough and ductile alpha phase tantalum is preferred over the hard and brittle beta phase tantalum, as a protective coating. Alpha phase coatings were successfully deposited …

In-Plane Anisotropy And Temperature Dependence Of Oxygen Phonon Modes In Yba2⁢Cu3⁢O6.95, J-H Chung, Takeshi Egami, Rj Mcqueeney, Mohana Yethiraj, Masatoshi Arai, Tetsuya Yokoo, Y. Petrov, Herbert A. Mook, Yasuo Endoh, Setsuko Tajima, C. Frost, Fatih Dogan

Materials Science and Engineering Faculty Research & Creative Works

Inelastic pulsed neutron scattering measurements on YBa₂⁢Cu₃⁢O_6.95 single crystals indicate that the sample has a distinct a-b plane anisotropy in the oxygen vibrations. The Cu-O bond-stretching-type phonons, which are suspected to interact strongly with charge, are simultaneously observed along the a and b directions due to a 7-meV splitting arising from the orthorhombicity, even though the sample is twinned. The bond-stretching LO branch with the polarization along a (perpendicular to the chain) loses intensity beyond the middle of the zone, indicating branch splitting as seen in doped nickelates, with the second branch being located at …

Application Of Dynamic System Identification To Timber Bridges, S T. Peterson, D I. Mclean, David Pollock

Faculty Publications - Biomedical, Mechanical, and Civil Engineering

A method of global nondestructive evaluation for identifying local damage and decay in timber beams was developed in previous analytical studies and verified experimentally using simply supported beams in the laboratory. The method employs experimental modal analysis and an algorithm that monitors changes in modal strain energy between the mode shapes of a damaged structure with respect to the undamaged structure. A simple three-girder bridge was built and tested in a laboratory to investigate the capability and limitations of the method for detecting damage in a multimember timber structure. The laboratory tests showed that the method can correctly detect and …

Thermal Assessment Of Silicon-Based Composite Materials Used In Photovoltaics, Pavlos K. Bataglannis

Theses

Photovoltaics are devices that convert sunlight directly to electricity. It is well established that the conversion efficiency of mono and poly-crystalline silicon-based photovoltaic modules is inversely related to their temperature. Substantial improvements in operational performance can thus be achieved if the thermal energy accumulating in the material can be effectively dissipated.

Accurate modelling of modules would allow possible methods of thermal dissipation to be evaluated, and as a crucial component of the model, the thermal properties of the constituent materials of PV modules needed to be known. Special consideration needed to be given to the interfaces between dissimilar materials and …

Dynamics Of Bulk And Adsorbed Poly(Vinyl Acetate), Frank D. Blum, Robert D. O'Connor

Materials Science and Engineering Faculty Research & Creative Works

We have recently completed a series of experiments on methyl-labeled poly(vinyl acetate)-d3, (PVAc-d3)1 and poly(methyl acrylate)-d3 (PMA-d3).234 the systems have been studied as a function of the adsorbed amount, molecular weight, and presence of a protonated overlayer. Using deuterium line shape analysis, we have found that around the glass transition temperature, the adsorbed polymers show the presence of a motional gradient. Polymer segments near the silica-polymer interface have less mobility than the bulk polymer and those near the polymer-air interface are more mobile than those of the bulk polymer. A schematic representation of the motional gradient is shown in Figure …

Influence Of Nanocrystalline Grain Size On The Breakdown Strength Of Ceramic Dielectrics, Yang Ye, Fatih Dogan, E. Schamiloglu, J. Gaudet, P. Castro, M. Roybal, M. Joler, C. Christodoulou, Shi C. Zhang

Materials Science and Engineering Faculty Research & Creative Works

In an effort to develop transmission lines with higher energy storage capabilities for compact pulsed power applications, the University of Missouri-Rolla (UMR) and the University of New Mexico (UNM) have undertaken a collaborative approach to developing and studying ceramic dielectrics. At UMR, the electrical breakdown strength (BDS) of TiO2-based materials is investigated for high energy density applications. The results of research to-date show that dense titania ceramics with nanocrystalline grain size (~200 nm) exhibit significantly higher BDS as compared to ceramics made using coarse grain materials. Processing-microstructure-property relationships in TiO2 systems are found to play a role with respect to …

Comparison Of Anode And Electrolyte Support Configuration Of Single-Chamber Sofc, Piotr Jasinski, Toshio Suzuki, Zach Byars, Fatih Dogan, Harlan A. Anderson

Materials Science and Engineering Faculty Research & Creative Works

The single-chamber solid oxide fuel cell (SOFC) has recently received considerable attention. This type of fuel cell operates in the mixed reactant gas and therefore does not require separation of the fuel and oxidant gases. In this paper we report the anode- and electrolyte-supported configurations of the single chamber SOFC that we have studied. The system based on typical fuel cell composition has been examined: yttrium stabilized zirconia (YSZ) as an electrolyte, nickel/YSZ cermet as an anode, lanthanum strontium manganese oxide (LSM) as a cathode. The cells were prepared by tape-casting and screen-printing techniques. The cathode processing parameters have been …

Ft-Ir Studies Of Stereo Regular Pmma On Silica: Drying Effects, Bing Zhang, Suntree Kulkeratiyut, Suriyaphongse Kulkeratiyut, Frank D. Blum

Chemistry Faculty Research & Creative Works

A great amount of work has been done on the configuration of surface adsorbed poly(methyl methacrylate) (PMMA), especially on surfaces to which they have a strong attraction. Some studies have been make on the relationships between configuration and tacticity, molecular weight, adsorbed amount, and density of surface hydroxyl groups. The effect of tacticity on the conformation of alumina-adsorbed PMMA in solution and dry spin-coated films were studied by Grohen et al. Their results showed that surface-adsorbed PMMA chains adopted a relatively flat configuration, but iso-PMMA (isotactic) adsorbed on aluminum, with a much larger fraction of the bound carbonyl groups, had …

Molecular Mass And Dynamics In Pma-D₃ In The Glass Transition Region, Burak Metin, Frank D. Blum

Chemistry Faculty Research & Creative Works

The segmental dynamics through the glass transition region, by which the glassy polymer becomes rubbery, are not well understood. Free volume, thermodynamic and kinetic theories have been used to describe the phenomenon behind the glass transition and some of those theories were tested with computer simulations. Different experimental techniques, such as NMR, thermo-mechanical analysis (TMA), differential scanning calorimetry (DSC), dilatometry and dynamic mechanical analysis (DMA) have all been also used to probe this important phenomena. Deuterium (2H) NMR has been a valuable tool for the investigation of the dynamics of macromolecules. Deuteration of macromolecules at specific locations on the chains …

Deuterium Nmr Studies Of Bulk And Silica-Absorbed Polystyrene, Macduff O. Okuom, Jinhua Yang, Frank D. Blum

Chemistry Faculty Research & Creative Works

Thin polymer films are used in applications such as electronics, biomedical devices and coatings. As the trend to make the devices smaller continues, a film's influence on a material's overall properties becomes more prominent. Previous studies have shown that thin polymer films have characteristics slightly different from those of bulk polymers. Film behavior has been characterized by examining thermal expansion, diffusion, conformation, density and glass transitions. The dynamics of glassy polystyrene has been investigated using a wide variety of theoretical and experimental methods. Schaefer et al., using 13C NMR, reported that ~7% of phenyl rings in polystyrene undergo -flips. Using …

Bistable Memory Effect In Chromium Oxide Junctions, Andrei Sokolov, C.-S. Yang, E. Ovtchenkov, L. Yuan, Sy-Hwang Liou, Bernard Doudin

Materials Research Science and Engineering Center: Faculty Publications

Magnetotransport properties of granular CrO₂ /Cr₂O₃ films made of CrO₂ crystals covered by 1- 2 nm native insulating Cr₂O₃ are presented. Electrical properties of a limited number of grains measured in series and parallel (10 to 15 grains) reveal intergrain tunneling characteristics. At lowest temperatures, a well pronounced zero bias anomaly indicates that impurities in the junctions block the electronic flow.

Hysteresis in the IV curves are observed at intermediate temperatures on zero-field cooled samples. Changing the polarity of a short excitation pulse (100ns) of amplitude smaller than 1 V triggers a …

Substrate Dependent Bonding Of Chemisorbed 1,1’-Biphenyl-4,4’-Dimethanethiol, A. N. Caruso, R. Rajesekaran, Jody G. Redepenning, Yaroslav B. Losovyj, Peter A. Dowben

Materials Research Science and Engineering Center: Faculty Publications

We compare the adsorption of 1,1’-biphenyl-4,4’-dimethanethiol (BPDMT) on gold and cobalt surfaces. The molecular orbitals, identified from combined photoemission and inverse photoemission studies, exhibit shifts in binding energies with different deposition methods and substrates. These shifts indicate that this potential molecular dielectric exhibits stronger bonding to cobalt surfaces than gold surfaces.

Ultrafine Nife2o4 Powder Fabricated From Reverse Microemulsion Process, Jiye Fang, Narayan Shama, Le Duc Tung, Eun Young Shin, Charles J. O'Connor, Kevin L. Stokes, Gabriel Caruntu, John B. Wiley, Leonard Spinu, Jinke Tang

Physics Faculty Publications

NiFe2O4 ultrafine powder with high crystallinity has been prepared through a reverse microemulsion route. The composition in starting solution was optimized, and the resulting NiFe2O4 was formed at temperature of around 550–600 °C, which is much lower than that observed from the solid-state reaction. Magnetic investigation indicates that samples are soft-magnetic materials with low coercivity and with the saturation magnetization close to the bulk value of Ni ferrite.

Modeling, Fabrication, And Optimization Of Niobium Cavities: Final Phase, Robert A. Schill Jr., Mohamed Trabia

Transmutation Sciences Materials (TRP)

Niobium cavities are important parts of the integrated NC/SC high-power linacs. Over the years, researchers in several countries have tested various cavity shapes. They concluded that elliptically shaped cells are the most appropriate shape for superconducting cavities. The need for very clean surfaces lead to the use of a buffered chemical polishing produce for surface cleaning to get good performance of the cavities. This is the third and final phase of the study.

The first phase has resulted in improving the basic understanding of multipacting and the process of chemical etching. The second phase has resulted in an experimental setup …

Modeling, Fabrication, And Optimization Of Niobium Cavities, Robert A. Schill Jr., Mohamed Trabia, William Culbreth

Transmutation Sciences Materials (TRP)

One of the key technologies for the deployment of accelerator driven transmutation systems is the accelerator itself. To increase the efficiency of the high-power accelerators needed to support the transmutation mission, the national and international accelerator teams have proposed using elliptical superconducting niobium cavities. This project is tasked with examining the impacts of the design and fabrication technologies for these elliptical niobium cavities on their performance. Niobium was selected primarily due to its behavior at low temperatures.

One of the major sources of energy loss from a superconducting accelerator cavity is a process known as multiple impacting (or “multipacting”) of …

Corrosion Of Steel By Lead Bismuth Eutectic, John Farley, Allen L. Johnson, Dale L. Perry

Transmutation Sciences Materials (TRP)

Materials for transmuter systems must be able to tolerate high neutron fluxes, great temperatures, and chemical corrosion. For lead bismuth eutectic (LBE) systems, there is an additional challenge in that the corrosive behaviors of materials in LBE are not well understood. Most of the available information on LBE systems has come from the Russians, who have over 80 reactor-years experience with LBE coolant in their Alpha-class submarine reactors. The Russians found that the presence of small amounts of oxygen (on the order of parts per million) in the LBE significantly reduced corrosion. However, a fundamental understanding and verification of its …

Surface Studies Of Corrosion Of Stainless Steel By Lead Bismuth Eutectic, Daniel Koury, Brian D. Hosterman, John Farley, Dale L. Perry, D. Parsons, J. Manzerova, Allen L. Johnson

Transmutation Sciences Materials (TRP)

Why is Lead Bismuth Eutectic Important?

• Changing national security stances have led to reexamination of nuclear waste reprocessing

• Dangerous actinides can be separated and

• Transmuted into safer products, creating a waste form dangerous for only hundreds of years, in addition to the production (up to 1/3 of the original fission energy) of useful energy

• Non-moderating coolants or spallation targets for production of fast neutrons is required for transmutation

• Russian experience with LBE coolants in their nuclear submarine fleet makes LBE an attractive possible transmutation coolant technology

• Corrosion of steel by LBE is an important …

Environment-Induced Degradation And Crack-Growth Studies Of Candidate Target Materials, Ajit K. Roy, Brendan O'Toole, Zhiyong Wang, David W. Hatchett

Transmutation Sciences Materials (TRP)

The primary objective of this task is to evaluate the potential for the environmentally-assisted cracking of candidate target materials for applications in spallation-neutron-target systems, such as accelerator-driven system for the transmutation of waste. The materials selected for evaluation and characterization are martensitic stainless steels (SS) including Alloys HT- 9, EP 823 and Type 422 stainless steel.

More recently, this experimental program has been expanded to evaluate the effect of molten lead-bismuth eutectic (LBE) on the corrosion behavior of target materials in the presence of oxygen. Since the materials performance laboratory (MPL) at UNLV currently cannot accommodate this type of testing, …

Modeling Corrosion In Oxygen Controlled Lbe Systems With Coupling Of Chemical Kinetics And Hydrodynamics, Samir Moujaes, Yitung Chen

Transmutation Sciences Materials (TRP)

The corrosion of structural materials is a major concern for the use of lead-bismuth eutectic (LBE) systems for nuclear applications such as in transmuter targets or fast reactors. Corrosion in liquid metal systems can occur through various processes, including, for example, dissolution, formation of inter-metallic compounds at the interface, and penetration of liquid metal along grain boundaries. Predicting the rate of these processes depends on numerous system operational factors: temperature, system geometry, thermal gradients, solid and liquid compositions, and velocity of the liquid metal, to name a few. Corrosion, along with mechanical and/or hydraulic factors, often contributes to component failure. …

Modeling Of Corrosion In Oxygen Controlled Lead Bismuth Eutectic Systems With The Coupling Of Chemical Kinetics And Hydrodynamics, Samir Moujaes, Yitung Chen, Kanthi Kiran Dasika, Chao Wu

Transmutation Sciences Materials (TRP)

Objectives:

• To simulate a 2-D model of the Materials Test Loop by approximating it to be a toroid with a pie cross section for the purpose of comparing the simulated results with the analytical results.
• The temperature and concentration profiles on the wall boundaries imposed are similar to the actual test model.
• Geometry effects have great influence on local corrosion rate.
• A 2-D benchmark problem and a sudden expansion case are studied which show good consistency to analytical solution.
• Results from 2-D sudden expansion problem are similar to experimental data obtained by other researchers.