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Articles 1 - 18 of 18
Full-Text Articles in Engineering
Detection For A Statistically-Known, Time-Varying Dispersive Channel, David W. Matolak, S. G. Wilson
Detection For A Statistically-Known, Time-Varying Dispersive Channel, David W. Matolak, S. G. Wilson
Faculty Publications
Detection for the statistically known channel (SKC) is aimed at obtaining good performance in situations where our statistical knowledge of a time-varying channel is good, and where other equalization/detection schemes are either too complex to implement, or their performance is limited due to the rapidity of channel fading, or where we are simply unable to perform channel estimation. By using a statistical characterization of the channel, we develop a new detector that performs maximum-likelihood sequence estimation (MLSE) (given the channel model) on blocks of N symbols. Both symbol-spaced and fractionally spaced samples are used, to obtain two different detectors, that …
Characterization Of Sr‐Doped Lamno3 And Lacoo3 As Cathode Materials For A Doped Lagao3 Ceramic Fuel Cell, Kevin Huang, Man Feng, John B. Goodenough, Michael Schmerling
Characterization Of Sr‐Doped Lamno3 And Lacoo3 As Cathode Materials For A Doped Lagao3 Ceramic Fuel Cell, Kevin Huang, Man Feng, John B. Goodenough, Michael Schmerling
Faculty Publications
Energy dispersive spectrometry line scan and ac impedance spectroscopy were used in this study to investigate the chemical reactions between two cathode materials, La0.84Sr0.16MnO3 (LSM), La0.5Sr0.5CoO3-δ (LSC), and the electrolyte La0.9Sr0.1Ga0.8Mg0.2O2.85 (LSGM). Significant interdiffusions of Co into LSGM and Ga into LSC were found at an LSC/LSGM interface even at relatively low fabrication temperatures. In contrast, only small interdiffusions of Mn into LSGM and Ga into LSM were detected at the LSM/LSGM interface even though it was fired at 1470°C. The …
Characterization Of The Si/Sio2 Interface Formed By Remote Plasma Enhanced Chemical Vapor Deposition From Sih4/N2O With Or Without Chlorine Addition, Young-Bae Park, Xiaodong Li, Shi-Woo Rhee
Characterization Of The Si/Sio2 Interface Formed By Remote Plasma Enhanced Chemical Vapor Deposition From Sih4/N2O With Or Without Chlorine Addition, Young-Bae Park, Xiaodong Li, Shi-Woo Rhee
Faculty Publications
The Si/SiO2interface formed by remote plasma enhanced chemical vapor deposition (RPECVD) at low temperature with SiH4/N2O or SiH4/N2O/Cl2 was studied and compared with thermal oxidation. The interface of the CVD SiO2 without chlorine addition is rougher than that with chlorine addition. But the surface roughness of CVD SiO2 films increases with chlorine addition. The thermal oxidation induces strong interface strains, and the strains generated by the CVD SiO2 without chlorine addition are stronger and are distributed more nonuniformly than those by the chlorinated SiO2. …
Microstructure And Deposition Rate Of Aluminum Thin Films From Chemical Vapor Deposition With Dimethylethylamine Alane, Byoung-Youp Kim, Xiaodong Li, Shi-Woo Rhee
Microstructure And Deposition Rate Of Aluminum Thin Films From Chemical Vapor Deposition With Dimethylethylamine Alane, Byoung-Youp Kim, Xiaodong Li, Shi-Woo Rhee
Faculty Publications
Deposition of aluminumfilm from DMEAA in the temperature range of 100–300 °C has been studied. In this temperature range, there is a maximum deposition rate at around 150 °C. The film deposited at 190 °C has elongated blocklike grain shapes, which are ∼600 nm in width and 930 nm in length. Grains in the film deposited at 150 °C showed an equiaxed structure with grain size in the range of 100–300 nm in a film with 600 nm thickness. Aluminum oxide particle inclusion was observed especially at high deposition temperature. Plausible reaction pathways of DMEAA dissociation were suggested to explain …
Low-Frequency Noise In 4h-Silicon Carbide Junction Field Effect Transistors, J. W. Palmour, M. E. Levinshtein, S. L. Rumyantsev, Grigory Simin
Low-Frequency Noise In 4h-Silicon Carbide Junction Field Effect Transistors, J. W. Palmour, M. E. Levinshtein, S. L. Rumyantsev, Grigory Simin
Faculty Publications
Low frequency noise in 4H‐silicon carbide junction field effect transistors (JFETs) has been investigated. JFETs with a buried p + n junction gate were manufactured by CREE Research Inc. Very low noise level has been observed in the JFETs. At 300 K the value of Hooge constant α is as small as α∼10−5 and the α value can be decreased by an appropriate annealing to α∼2×10−6. It has been shown that even these extremely low noise values are determined not by the volume noise sources but by the noise at the SiC–SiO2 interface.
Variable-Complexity Trellis Decoding Of Binary Convolutional Codes, David W. Matolak, S. G. Wilson
Variable-Complexity Trellis Decoding Of Binary Convolutional Codes, David W. Matolak, S. G. Wilson
Faculty Publications
Considers trellis decoding of convolutional codes with selectable effort, as measured by decoder complexity. Decoding is described for single parent codes with a variety of complexities, with performance "near" that of the optimal fixed receiver complexity coding system. Effective free distance is examined. Criteria are proposed for ranking parent codes, and some codes found to be best according to the criteria are tabulated, Several codes with effective free distance better than the best code of comparable complexity were found. Asymptotic (high SNR) performance analysis and error propagation are discussed. Simulation results are also provided.
Use Of A Hydrogen Anode For Nitrate Waste Destruction, E. E. Kalu, Ralph E. White, D. T. Hobbs
Use Of A Hydrogen Anode For Nitrate Waste Destruction, E. E. Kalu, Ralph E. White, D. T. Hobbs
Faculty Publications
No abstract provided.
Galvanostatic Pulse And Pulse Reverse Plating Of Zinc–Nickel Alloys From Sulfate Electrolytes On A Rotating Disc Electrode, Branko Popov, M. Ramasubramanian, S. N. Popova, Ralph E. White, Ken-Ming Yin
Galvanostatic Pulse And Pulse Reverse Plating Of Zinc–Nickel Alloys From Sulfate Electrolytes On A Rotating Disc Electrode, Branko Popov, M. Ramasubramanian, S. N. Popova, Ralph E. White, Ken-Ming Yin
Faculty Publications
Galvanostatic pulse and pulse reverse techniques have been used to study the plating of zinc–nickel alloys in the presence of nonyl phenyl polyethylene oxide. The effects of average current density, rotation speed of disc electrode and the presence of nonyl phenyl polyethylene oxide in the electrolyte on deposition of zinc–nickel alloys were evaluated. Zinc–nickel plating bath solution chemistry was studied by determining the equilibrium concentrations at various pH levels. It was found that the alloy composition was determined by solution equilibria, mass transfer of the electroactive species within the diffusion layer and by the surface coverage of nonyl phenyl polyethylene …
Galvanostatic Pulse And Pulse Reverse Plating Of Zinc-Nickel Alloys From Sulfate Electrolytes On A Rotating Disc Electrode, Branko N Popov, M. Ramasubramanian, S. N. Popova, Ralph E. White, K-M. Yin
Galvanostatic Pulse And Pulse Reverse Plating Of Zinc-Nickel Alloys From Sulfate Electrolytes On A Rotating Disc Electrode, Branko N Popov, M. Ramasubramanian, S. N. Popova, Ralph E. White, K-M. Yin
Faculty Publications
Galvanostatic pulse and pulse reverse techniques have been used to study the plating of zinc–nickel alloys in the presence of nonyl phenyl polyethylene oxide. The effects of average current density, rotation speed of disc electrode and the presence of nonyl phenyl polyethylene oxide in the electrolyte on deposition of zinc–nickel alloys were evaluated. Zinc–nickel plating bath solution chemistry was studied by determining the equilibrium concentrations at various pH levels. It was found that the alloy composition was determined by solution equilibria, mass transfer of the electroactive species within the diffusion layer and by the surface coverage of nonyl phenyl polyethylene …
Analysis Of Transient Hydrogen Uptake By Metal Alloy Particles, Wenlin Zhang, Supramaniam Srinivasan, Harry J. Ploehn
Analysis Of Transient Hydrogen Uptake By Metal Alloy Particles, Wenlin Zhang, Supramaniam Srinivasan, Harry J. Ploehn
Faculty Publications
This paper describes a new approach to solving the equations comprising the shrinking core model for diffusion and reaction of a chemical species in a solid spherical particle. The reactant adsorbs on the particle surface, diffuses into the particle's interior, and reacts with the particle to form a solid product. The shrinking core model assumes a fast reaction rate compared to reactant diffusion so that the reaction is localized in the interfacial zone between the unreacted solid core and the surrounding shell of reacted product. Analytical solutions of the governing conservation equations usually invoke the pseudo-steady state (PSS) approximation which …
Linear Algebra Used To Determine Independent Half‐Cell Equations, D. H. Coleman, Ralph E. White
Linear Algebra Used To Determine Independent Half‐Cell Equations, D. H. Coleman, Ralph E. White
Faculty Publications
No abstract provided.
A Multiphase Mathematical Model Of A Nickel/Hydrogen Cell, Pauline De Vidts
A Multiphase Mathematical Model Of A Nickel/Hydrogen Cell, Pauline De Vidts
Faculty Publications
No abstract provided.
A Model For The Galvanostatic Deposition Of Nickel Hydroxide, Mahesh Murthy, Gowri S. Nagarajan, John W. Weidner, John W. Van Zee
A Model For The Galvanostatic Deposition Of Nickel Hydroxide, Mahesh Murthy, Gowri S. Nagarajan, John W. Weidner, John W. Van Zee
Faculty Publications
A mathematical model is presented for the galvanostatic deposition of Ni(OH)2 films in stagnant Ni(NO3)2 solutions. The objective is to quantify the anomalous deposition behavior reported previously in which the utilization of the electrochemically generated OH– species decreased drastically as the concentration of Ni(NO3)2 increased beyond 0.1 M. For example as the Ni(NO3)2 concentration increased from 0.1 to 2.0 M, the deposition rate decreased by a factor of ten at 2.5 mA/cm2. At this high ratio of concentration to current density, a comparison with Faraday's …
Anodic Oxidation Of Ethylenediaminetetraacetic Acid On Platinum Electrode In Alkaline Medium, S. N. R. Pakalapati, Branko N. Popov, Ralph E. White
Anodic Oxidation Of Ethylenediaminetetraacetic Acid On Platinum Electrode In Alkaline Medium, S. N. R. Pakalapati, Branko N. Popov, Ralph E. White
Faculty Publications
The anodic oxidation of ethylenediaminetetraacetic acid (EDTA) was studied in alkaline medium on a smooth platinum electrode. Bulk electrolysis indicated that stable organic intermediates (formaldehyde and glyoxal) are formed during the oxidation of EDTA and that complete oxidation to CO2 can be achieved. The proposed pathway suggests that the acetate groups in EDTA are initially oxidized, generating formaldehyde and ethylenediamine. The rest potential of EDTA (0.066 to 0.164 V vs. Hg/HgO) was observed to be higher than for other organic species. In alkaline medium, very little EDTA oxidation was found to occur on bare platinum. Limiting-current behavior due to …
The Effects Of Multiple Electroplated Zinc Layers On The Inhibition Of Hydrogen Permeation Through An Iron Membrane, D. H. Coleman, G. Zheng, Branko N. Popov, Ralph E. White
The Effects Of Multiple Electroplated Zinc Layers On The Inhibition Of Hydrogen Permeation Through An Iron Membrane, D. H. Coleman, G. Zheng, Branko N. Popov, Ralph E. White
Faculty Publications
The Devanathan-Stachurski permeation technique was used to investigate the rate of hydrogen permeation through an iron membrane with consecutively electroplated zinc layers. Hydrogen evolution rates and hydrogen permeation rates were followed as functions of time at different applied potentials. Hydrogen evolution and permeation decreased with each successive zinc layer until finally reaching an average decrease of 93 and 96%, respectively, as compared with bare iron. Hydrogen surface coverage, exchange current density, absorption-adsorption reaction constant, and hydrogen recombination constant were estimated on bare iron and on zinc-plated iron. It was found that the decrease in the permeation rate of hydrogen through …
Anomalous Codeposition Of Fe-Ni Alloys And Fe-Ni-Sio2 Composites Under Potentiostatic Conditions, M. Ramasubramanian, S. N. Popova, Branko N. Popov, Ralph E. White, K. M. Yin
Anomalous Codeposition Of Fe-Ni Alloys And Fe-Ni-Sio2 Composites Under Potentiostatic Conditions, M. Ramasubramanian, S. N. Popova, Branko N. Popov, Ralph E. White, K. M. Yin
Faculty Publications
A mathematical model has been developed to describe the electrodeposition of Fe-Ni alloys and Fe-Ni-SiO2 composites under potentiostatic conditions. This model can be used to predict the polarization behavior, partial current densities, and alloy composition of each of the components as a function of the applied potential. Fe-Ni-SiO2 samples were deposited on platinum rotating disk electrodes from sulfate electrolytes under potentiostatic conditions, and the results obtained were compared to the model. The model predictions were found to agree well with the experimental observations for the Fe-Ni and Fe-Ni-SiO2 systems.
Determination Of Transport And Electrochemical Kinetic Parameters Of Bare And Copper-Coated Lani4.27Sn0.24 Electrodes In Alkaline Solution, G. Zheng, Branko N. Popov, Ralph E. White
Determination Of Transport And Electrochemical Kinetic Parameters Of Bare And Copper-Coated Lani4.27Sn0.24 Electrodes In Alkaline Solution, G. Zheng, Branko N. Popov, Ralph E. White
Faculty Publications
Electrochemical properties of bare and copper-coated LaNi4.27Sn0.24 electrodes were investigated in alkaline solution. The exchange current density, polarization resistance, and equilibrium potential were determined as functions of the state of charge in the electrodes. The symmetry factors for bare and copper-coated electrodes were estimated to be 0.53 and 0.52, respectively. By using a constant current discharge technique, the hydrogen diffusion coefficient in bare and coated LaNi4.27Sn0.24 was estimated to be 6.75 × 10–11 cm2/s.
Application Of Porous Electrode Theory On Metal Hydride Electrodes In Alkaline Solution, G. Zheng, Branko N. Popov, Ralph E. White
Application Of Porous Electrode Theory On Metal Hydride Electrodes In Alkaline Solution, G. Zheng, Branko N. Popov, Ralph E. White
Faculty Publications
Porous electrode theory was applied to estimate the exchange current density, the polarization resistance, and symmetry factor for LaNi4.27Sn0.24 hydride electrode in alkaline solution. The exchange current density, polarization resistance, and symmetry factor were determined from polarization curves which were obtained at low overpotentials.