Engineering Commons^™

The Study On Fabricating Thin Electrodes For Polymer Electrolyte Membrane Fuel Cells (Pemfc), Yong-Sheng Yang, Jing-Hua Liu, Chang-Peng Liu, Gong-Quan Sun, Chang-Zhi Li, Tian-Hong Lu

Journal of Electrochemistry

To lower platinum loading in electrodes for polymer electrolyte membrane fuel cell, a new thin electrode fabrication technique (TEFT) was developed in this work. A series of low Pt loading electrodes with smooth and uniformed surface were fabricated by the TEFT. As a result, the maximum power density of the cell with platinum loading of 1 mg/cm² and Nafion 117 membrane as electrolyte was up to 0.3 W.cm^-2. Moreover, the effects of PTFE and Nafion content in cathodes on the performance of PEMFC with low Pt loading electrodes (1 mg Pt/cm²) were examined systematically.

Sprayed And Thermally Evaporated Carbon Films As Anodes For Lithium Ion Batteries, Shu-Gao Zhang, M.Schleich Donald

Journal of Electrochemistry

Carbon films were made using spray-thermal evaporation from a kind of pyrolytic carbon powder. The films obtained with graphite structure were both potentio-statically and galvanostaically tested. Cycling patterns indicated a reduction peak on the first cycle corresponding to the formation of solid electrolyte interface, and the capacity values and x values were quite acceptable compared to theoretical ones when charging-discharging current density was suitable. Based on the experimental results, the obtained carbon films could be used as anode materials for relatively determining the electrochemical performances of cathode materials.

Studies On Electrochemical Synthesis Of 4,5-Disubstituted-1,2- Benzoquinones And The Reaction Mechanism, Xian-Zhang Bu, Gui-Wu Xiao, Lin Ma, Xing-Chum He, Ling-Quan Gu

Journal of Electrochemistry

The oxidation peak potentials (E_p) of alinine derivates and catechol in 0.1 mol/L KCl+15% alcohol solution were measured by cyclic voltammograms technique. The electrochemical oxidation condition was set according to the E_p. Three derivates of 4,5-disubstituted -1,2-benzoquinones were prepared via electrochemical oxidation-Michael addition reaction. The possible mechanism of electrochemical oxidation-Michael addition reaction is presented.

Study On Preparation Of Coarse And Fine γ-Lialo2 Mixed Powder Used For Mcfc Matrix, Hua-Xin Lin, Bao-Lian Yi, Lian-Ying Kong, En-Jun Zhang, Li Zhou, Feng-Xia Wang

Journal of Electrochemistry

Coarse α-LiALO₂ powder was transferred completely to γ-LiAlO₂ at 900 ℃ for ten hours. Fine γ-LiALO₂ powder was prepared by “chloride” synthesis. MCFC matrix was fabricated by mixing the coarse and fine γ-LiALO₂ powder and by tape cast. The out'put voltage of the cell assembled with the matrix was 0.85 and 0.75 V respectively at 200 and 300 mA/cm ², and power density was about 250 mW/cm². The performance of the matrix fabricated with the mixed powder was obviously more advanced than that of the matrix fabricated with only coarse γ-LiALO₂ powder.

Electrochemical Characterization Of Ir-Ta-Ti Metal Oxide Coated Titanium Anodes, Ting-Yong Wang, Li-Kun Xu, Guang-Zhang Chen

Journal of Electrochemistry

Ir-Ta-Ti metal oxide coated titanium anodes of variable composition were prepared by thermal decomposition. Their micro morphorogies and electrochemical properties were characterized by scanning electron microscope, open circuit potential, cyclic voltammetry, consumption rate measurements and accelerated life test. The SEM results indicated that all coatings were of a porous and cracked-mud microstructure influenced greatly by the composition of coatings. The electrochemical measurements showed that the Ir-Ta-Ti ternary oxide-coated anodes exhibited excellent electrochemical activity and electrochemical stability in both acidic media and seawater which were affected by the composition and microstructure of the coatings. Owing to good corrosion resistance and low …

Fabrication And Examination Of Reduced Temperatrue Solid Oxide Fuel Cell Using A Supported Thin Ysz Electrolyte Substrate, Yi-Huang Zhang, Yong-Lei Dong, Yi Jiang, Zhi-Gui Lu, Jing-Wang Yan

Journal of Electrochemistry

By using a cost-effective wet process,dense yttria stabilized zirconia (YSZ) films on Ni-YSZ anode substrates have been prepared successfully. The YSZ film was characterized to be around 10 μm in thickness, sufficiently dense, uniform and crack free. A single solid oxide fuel cell fabricated from the supported YSZ film electrolyte on the anode substrate and a LSM cathode prepared on the YSZ film was tested. The power density reached to 0.1 W/cm² at 800 ℃, showing a reasonable performance. Further analysis on both electrodes shows that the anodic overpotential was much larger than IR drop (including YSZ resistance and …

An Eis Study On The Synergetic Filming Between Cathodic Protection And The Corrosion Inhibitor, Yong-Tao Zhao, Jian-Hua Wu, Jian-Hua Qian, Hui Yu

Journal of Electrochemistry

The electrochemical impedance spectroscope (EIS) of 907A steel in seawater was investigated to study the film formation and destruction. The corrosion protection mechanism of the synergy interaction between cathodic protection and YKI-5 corrosion inhibitor (a mixture of polyhydric alcohol phosphate ester, phosphate and polyphosphate) is discused. Typical EIS spectral changes were clearly observed during the film formation and destruction processes. EIS results indicated that the film seemed to formed a multi-layered structure which consist of an inner layer (this may be an inhibitor-metal complex layer) and many outer layers of calcareous deposits. The film possesses of good persistency under the …

Electro-Oxidation Of Glyoxal To Glyoxalic Acid, Yin-Sheng Chen, Xin-Sheng Zhang, Jun Hu, Ying-Chun Dai

Journal of Electrochemistry

An investigation has been made to obtain the glyoxalic acid by the electrochemical oxidation of glyoxal solution with hydrochloric acid under various experimental conditions.The cell used consists of a lead cathode, a DSA anode and a cation-exchange membrane of model CM001. The current efficiency and yield for glyoxalic acid generation were 80.0% and 91.1% respectively, under optimal operating conditions: velocity of electrolyte flow 1.4 m·s^-1 ,current density 450 A·m^-2, temperature 30～40 ℃, initial concentration of glyoxal and hydrochloric acid 9.1%～16.0%, 4%～6%, respectively.

Photoresist Coating Process Control With Solvent Vapor Sensor, Richard N. Savage, Herbert Litvak, Emir Gurer

Materials Engineering

An apparatus for spin coating surfaces with liquid polymer comprises a spin coating chamber having a rotatable chuck for supporting an object to be coated. A distributor introduces gases into the chamber. A solvent vapor and carrier gas supply provides a carrier gas having a controlled level of solvent vapor therein within the range of from 0 to saturation concentrations of solvent vapor. A solvent vapor sensor is positioned with respect to the coating chamber to produce signals which correspond to the concentration of solvent vapor in the coating chamber. A control means is connected to the solvent vapor concentration …

Governing Yield Modes For Common Bolted And Nailed Wood Connections, Brian J. Tucker, David Pollock, Kenneth J. Fridley, Jeffrey J. Peters

Faculty Publications - Biomedical, Mechanical, and Civil Engineering

Connections in wood structures are important when designing for ductility. The 1997 Uniform Building Code has taken this into consideration when designating wind and earthquake load duration factors for connections. Factors of 1.6 or 1.33 may be applied to the connection strength, depending on the type of yield mode exhibited by the connection, which may be determined from the yield limit equations supplied in the National Design Specification for Wood Construction (NDS). The NDS provides the designer with multiple tables containing capacities for various common connections. Unfortunately, yield modes are not published along with tabulated capacities. Therefore, the designer must …

Infrared Spectoscopy And Electrical Conductivity Of Copper(Ii) 4-Aminobenzoate And Iondine-Doped Copper(Ii) 4-Aminobenzoate, Chang Fu Dee

Student Works (2000-2009)

Copper(II) 4-aminobenzoate (CAB), prepared from copper(II) acetate monohydrate and 4-aminobenzoic acid, was a dark green powder. Fourier Transfonn lnfrared (FTIR) spectrum of CAB, recorded as KBr disc, indicated the presence of all bonds and functional groups expected of it, and the absence of hydrogen bonding. Its conductivity at room temperature was 4.2 x 10^-11 Scm^·1. The value increased as temperature decreased indicating metallic behaviour. Density of states at Fenni level, hopping distance, hopping energy and density of charge carriers calculated based on Mon's Variable Range Hopping model (VRH) are 2.65x 10^-22 (eV)^-1 cm^-3, 7.47 x 10^-8 cm, 0.02 eV and …

Investigations On The Conductivity Of Organotin-Doped Polyethyleneoxide Polymer System, Lekshmi Sarojiniamma

Student Works (2000-2009)

Poly(ethylene oxide) (PEO) has been doped with selected organotin compounds. The organotin dopants used were triphenyltin thiocyanate (Ph3SnSCN) and tetramethylammonium dichlorotriphenylstannate [Ph3SnClr[Me4N)•. Tin incorporation in the polymers was established by several physical techniques. The infrared spectroscopic analysis of the Pb3SnSCN - doped electrolyte film showed bands at 2080-2050 cm.·' which are also given by pure Ph3SnSCN. Different concentrations of organotin doped electrolytes were prepared and conductivity studies on these were perfonned using impedance spectroscopy. From the measurements it was found that the best conductivity of 7.6xJ0.g Siem was obtained for the composition with PEO :dopant ratio of90:10 at room temperature. …

Evaluation Of Lsco Electrodes For Sensor Protection Devices, Robert W. Schwartz, M. T. Sebastian

Mechanical and Aerospace Engineering Faculty Research & Creative Works

We have evaluated lanthanum strontium cobalt oxide (La0.50Sr0.50CoOx; LSCO 50/50) as a candidate “transparent” electrode for use in an electrostatic shutter-based infrared sensor protection device. The device requires that the electrode be transparent (80% transmission) and have moderate sheet resistance (300 - 500 Ω/sq.). To meet these needs, the effects of postdeposition annealing on the resistivity and optical absorption characteristics of sputter deposited LSCO thin films were studied. The as-deposited films were characterized by an absorption coefficient of ~ 12,500 cm-1 and resistivities of ~ 0.08 to 0.5 Ω-cm. With annealing at 800°C, the resistivity decreased to 350 μΩ-cm, while …

Dynamics Of Interfacial Polymers In Composites, Frank D. Blum, Wuu-Yung Lin

Chemistry Faculty Research & Creative Works

Much experimental and theoretical work has been done on the behavior of adsorbed polymers. However, not much work has focused on the dynamics, especially segmental dynamics, of the adsorbed polymers. This is especially true of filled polymer or composite systems as the interfacial layers in these systems are difficult to study with most techniques. NMR is not restricted to use in optically clear samples and its use in the characterization in the surface polymers has been reviewed. In our laboratory, we have found that deuterium NMR could be used to probe the segmental dynamics of adsorbed polymers. The position of …

The Anomalous Behavior Of Al³⁺ In Nickel Electrowinning From Sulfate Electrolytes, Michael Holm, Thomas J. O'Keefe

Materials Science and Engineering Faculty Research & Creative Works

The effect of varying concentrations of Al³⁺ on the morphology and current efficiency of electrodeposited nickel from an acid-sulfate electrolyte was studied. Concentrations of Al³⁺ of 20 to 100 ppm significantly degraded the nickel-cathode morphology and current efficiency. However, it was found that higher concentrations of Al³⁺, in the range of 1 to 5 g/L, depending on the electrolyte parameters and operating conditions, improved the deposit morphology compared to deposition from a pure electrolyte. However, the current efficiency remained low. Physical characterization of the nickel revealed that a smoother, more uniform surface resulted from deposition in …

Modeling And Characterization Of Electrical Transport In Oxygen Conducting Solid Electrolytes, Igor Kosacki, Vladimir Petrovsky, Harlan U. Anderson

Materials Science and Engineering Faculty Research & Creative Works

A model for the electrical conductivity in acceptor-doped oxides which involves an association between the acceptor-dopants and oxygen vacancies resulting in donor centers is considered. The model relates the behavior of the electrical conductivity with the temperature, ambient atmosphere and band structure. The predictions of the model are compared to experimental data for ZrO2:16% Y and SrCeO3:5% Yb oxygen conductors and some band structure parameters have been determined.

Influence Of Gas Flow Rate On Oxygen Flux Measurements For Dense Oxygen Conducting Ceramic Membranes, W. T. Stephens, T. J. Mazanec, Harlan U. Anderson

Materials Science and Engineering Faculty Research & Creative Works

Oxygen transport through a dense oxygen conducting ceramic membrane is driven by an oxygen activity gradient imposed by the gas streams on either side of the membrane. The oxygen activity on each side of the membrane is altered as oxygen is transported across the membrane. Thus, the oxygen activity gradient will not be the same in each region of a membrane and will generate a different oxygen flux. This interaction between the oxygen gradient and the oxygen flux can produce a lower average oxygen flux across the membrane, can mask differences between materials, and can explain the dependence of oxygen …

Local Environment Of Iron And Uranium Ions In Vitrified Iron Phosphate Glasses Studied By Fe K And Uliii-Edge X-Ray Absorption Fine Structure Spectroscopy, Mevlüt Karabulut, G. K. Marasinghe, C. S. Ray, D. E. Day, George Daniel Waddill, P. G. Allen, C. H. Booth, J. J. Bucher, D. L. Caulder, D. K. Shuh, M. Grimsditch, M.-L. Saboungi

Materials Science and Engineering Faculty Research & Creative Works

The local structure of iron and uranium ions in a series of iron phosphate glasses with the general composition (40 - x)Fe₂O₃-xUO₂-60P₂O₅ and (1-x-y)(40Fe₂O₃-60P₂O₅)-xUO_2-y(Na₂O or CaO) was investigated using Fe K-edge and U L_III-edge x-ray absorption fine structure spectroscopy. Replacing Fe₂O₃ by UO₂ in the glass caused more distortion in the coordination environment of Fe(III) ions. Extended x-ray absorption fine structure fits revealed that the Fe-P bonds observed in the base glass also …

Effect Of Antioxidants On Ultra High Molecular Weight Polyethylene (Uhmwpe), Clifford Schrader

Masters Theses

This thesis presents a study on the effects of antioxidants on the oxidative induction time (OIT), thermal behavior, and hardness property of ultra high molecular weight polyethylene (UHMWPE). The antioxidants were dissolved into methanol alcohol before the solution was mixed with UHMWPE powder. The mixture was degassed under vacuum, and then compression-molded into disks 1.25 in. in diameter.

Different antioxidants were evaluated at concentrations up to 0.6 percent. A 0.6 percent concentration was used to screen the effectiveness of various antioxidants. Effect of antioxidant concentration was investigated in the range between 0 and 0.6 percent. OIT was evaluated on UHMWPE …

Synthesis Of Thermally Stable, High Surface Area Anatase–Alumina Mixed Oxides, Suresh Pillai, Hareesh Us, Rajeshkumar S, Mukundan P, Kgk Warrier

Articles

No abstract provided.

The Effects Of Argon Dilution On Hydrogenated Amorphous Silicon Prepared By D.C. Plasma Glow Discharge : Optical And Infrared Spectroscopic Studies, Aniszawati Azis

Student Works (2000-2009)

Hydrogenated amorphous silicon (a-Si :H) films were prepared from the discharge of pure silane and silane diluted in argon using a home-built hori zontal direct current(d.c.) plasma glow discharge system. The effects of argon dilution of silane on the optical properties, chemical bonding properties, hydrogen content and microstructure parameter of the films produced were studied and analyzed. Film thickness, refractive index, optical energy gap and the Urbach tail bandwidth were obtained from the optical transmission spectra of the films while the H content and the microstructure parameter were derived from the Fourier Transform infra-red(FTIR) spectra of the films. The FTIR …

Textured Mos 2 Thin Films Obtained On Tungsten: Electrical Properties Of The W/Mos 2 Contact, E. Gourmelon, J. C. Bernède, J. Pouzet, S. Marsillac

Electrical & Computer Engineering Faculty Publications

Textured films of molybdenum disulfide have been obtained by solid state reaction between the constituents in thin films form when a (200) oriented tungsten sheet is used as substrate. The crystallites have their c axis perpendicular to the plane of the substrate. The annealing conditions are T=1073K and t=30 min. The films are stoichoimetric and p type. Such highly textured films are achieved without foreign atom addition (Ni, Co...). It appears, as shown by x-ray photoelectron spectroscopy, that a thin WS₂ layer is present at the interface W/MoS₂. The crystallization process is discussed by a …

Organic Solution Deposition Of Copper Seed Layers Onto Barrier Metals, H. Gu, R. Fang, Thomas J. O'Keefe, Matthew O'Keefe, W. S. Shih, J. A.M. Snook, K. D. Leedy, R. Cortez

Materials Science and Engineering Faculty Research & Creative Works

Spontaneous deposition of copper seed layers from metal bearing organic based solutions onto sputter deposited titanium, titanium nitride, and tantalum diffusion barrier thin films has been demonstrated. Based on electrochemically driven cementation exchange reactions, the process was used to produce adherent, selectively deposited copper metal particulate films on blanket and patterned barrier metal thin films on silicon substrates. The organic solution deposited copper films were capable of acting as seed layers for subsequent electrolytic and electroless copper deposition processes using standard plating baths. Electroless and electrolytic copper films from 0.1μm to 1.0μm thick were produced on a variety of samples …

Microstructure - Property Relationships In Nanocrystalline Oxide Thin Films, I. Kosacki, Harlan U. Anderson

Materials Science and Engineering Faculty Research & Creative Works

Results of studies of the preparation, structure and physical properties of nanocrystalline CeO₂, ZrO₂:16%Y (YSZ) and SrCeO 3:5%Yb oxide thin films are presented. A polymeric precursor spin coating technique has been used to obtain dense specimens with stable and uniform microstructure controlled in the grain size range of 1-400 nm. A variety of characterization techniques including X-ray diffraction, impedance spectroscopy, Raman scattering and optical absorption have been used for the evaluation of the microstructure-property relationships. Nanocrystalline specimens are characterized by enhanced electrical conductivity and different stoichiometry compared with microcrystalline materials. A direct comparison has been achieved …

Electrical And Thermal Properties Of La0.2sr0.8cu0.1fe0.9o3-Δ And La0.2sr0.8cu0.2fe0.8o3-Δ, Ingeborg Kaus, Harlan U. Anderson

Materials Science and Engineering Faculty Research & Creative Works

La_0.2Sr_0.8Cu_0.1Fe_0.9O_3-δ and La_0.2Sr_0.8Cu_0.2Fe_0.8O^3-δ both exhibit cubic perovskite structures with lattice parameters a = 0.38711 and 0.38694 nm, respectively. The initial oxygen non-stoichiometry, δ, of the as-synthesized materials was 0.24 for the sample with 10% Cu and 0.34 for 20% Cu. La_0.2Sr_0.8Cu_0.1Fe_0.9O_3-δ has a lower p O (2) stability limit at 1x10-4 atm, whereas La_0.2Sr_0.8Cu_0.2Fe_0.8O_3-δ starts to decompose at 1x10-3 atm. The conductivity is approximately …

Al2o3-Ni Composites With High Strength And Fracture Toughness, William Fahrenholtz, Donald T. Ellerby, Ronald E. Loehman

Materials Science and Engineering Faculty Research & Creative Works

Al₂O₃-Ni Composites Were Prepared by the Reactive Hot Pressing of Al and NiO. the Composites Had a Two-Phase, Interpenetrating Microstructure and Contained Approx. 35 Vol% Ni. They Exhibited an Impressively High Combination of Strength and Toughness at Room Temperature; the Four-Point Bending Strength Was in Excess of 600 MPa with a Fracture Toughness of More Than 12 MPa·m^1/2 . Examination of Fracture Surfaces Showed that Ni Ligaments Underwent Ductile Deformation during Fracture. SEM Analysis Revealed Knife-Edge Ni Ligaments with a Limited Amount of Debonding Around their Periphery (I.e., at the Ni-Al₂O₃ Interface), …

Electrodeposition Of Copper On Polished Copper Electrode, Jia Tsung Ling

Student Works (2000-2009)

This project studies the surface morphology of the copper deposit from three different bath solutions on polished copper (3.1 mm in diameter) electrode by using Scanning Electron Microscopy. The behaviour of glycine as an additive in a bath solution containing 0.3 M of copper (II) sulphate and 2.2 M of sulphuric acid was studied by using cyclic voltammetry. In this project, glycine did not involved directly in the reaction of CU²⁺/CU couple but increased the potential and current density of the plating process. However, glycine has the properties for inhibiting the deposition of copper onto the copper disc. Moreover, block …

An Evaluation Of The Ductile Iron Casting Training Program At The Industrial Technology Department Of A Midwestern University, Khalid D. Alkarimy

Dissertations and Theses @ UNI

The purpose of this study is to determine how efficient this training program is as measured by (a) increasing the knowledge of new employees about the ductile iron casting process and other casting processes as perceived by the participants, (b) participants achievement of the program learning objectives as perceived by the participants, and (c) a positive reaction and attitude toward the program contents, instructors, facility and handout as perceived by the participants. The problem of this study is to evaluate the effectiveness of the Ductile Iron Casting Training program offered by the Industrial Technology department of a Midwestern University to …

Pre-Inoculation Effect Of Sic In Production Of Thin Wall Ductile Iron Castings, Nikolay Y. Laukhin

Dissertations and Theses @ UNI

Pre-inoculation effect of SiC additions and its effect on castability, microstructure, and magnesium recovery in thin wall ductile iron plates have been studied. Experimental results were compared with alternative FeSi75 furnace pre-inoculation additions.

The first series of experiments aimed to set the baseline of iron quality, when using FeSi75 pre-inoculant

In the second series of experiment, different methods of introduction of Sic into liquid iron were studied. It was established that Sic added into the stream during the tapping into the flow-through chamber or added directly into the flow-through chamber produced lower Si recovery. The most effective method of introduction …

Quantitative Analysis Of Ultra-Fine Goethite In Rust Layer On Steel Using Mossbauer And X-Ray Diffraction Spectroscopy, Masato Yamashita, Toshihei Misawa, H. E. Townsend, D. C. Cook

Physics Faculty Publications

We have proposed determination procedure of the relative amounts of rust constituents of steel. Mossbauer spectroscopy provides the relative amounts of crystalline rust constituents including ultra-fine crystals. A quantitative analysis of ultra-fine crystals is possible with the resolution of several percent by comparing the Mossbauer results with the relative amounts of rust constituents determined by X-ray diffraction spectroscopy.