Electrical and Computer Engineering Commons^™

Electrochemical Behavior Of Co-Ru Composite In Alkaline Solution, Su-Mei Yao, Guo-Chun Li, Xue-Ping Gao

Journal of Electrochemistry

The electrochemical properties of Ru doped cobalt hydroxides synthesized via homogeneous chemical co-precipitation were investigated in 6 mol·L^-1 KOH solution by galvanostatic charge-discharge process and cyclic voltammetry(CV).It is demonstrated that Ru doped cobalt hydroxides exhibited good capacitive characteristic and high specific capacitance.The sample with a Co/Ru molar ratio of 8 /1 shows the optimized electrochemical performance,including capacitive property and discharge capacity.The microstructure and morphology of the obtained Ru doped hydroxides were characterized by X-ray diffraction(XRD) and scanning electron microscope(SEM).The amorphous structure of ruthenium dioxide nanoparticles and single-crystal structure of Co(OH)₂ platelets were confirmed.Based on a structure analysis and …

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 …

Preparation And Characterizations Of Li3V2(Po4)3 Cathode Material For Lithium Ion Batteries, Hong Chen, Tao Jiang, Chun-Zhong Wang, Gang Chen, Ying-Jin Wei

Journal of Electrochemistry

The carbon-coated Li₃V₂(PO₄)₃ was prepared by carbothermal reduction method.The structural and morphological properties of the material were studied by X-ray diffraction,FTIR and transmission electron microscopy.The synthesized material was a pure phase of Li₃V₂(PO₄)₃,with the particle size of about 100 nm.The values of Li ion diffusion coefficient of the material in the potential window of 3.0 ～ 4.3 V were nearly 3 orders larger than those in 3.0 ～ 4.8 V.In addition,the charge-transfer resistances in 3.0 ～ 4.3 V were much smaller than those in 3.0 …

Frequency Response And Gain Enhancement Of Solid-State Impact-Ionization Multipliers (Sims), Joshua L. Beutler

Theses and Dissertations

A study of the frequency response and gain of Solid-state the Impact-ionization Multiplier (SIM). The SIM generates current gain via impact ionization also known as avalanche gain. The SIM provides low noise amplification from an arbitrary current source. In the case of this study, current sources consisted of photodiodes optimized for a particular wavelength of light. The SIM is fabricated from silicon and enjoys the low noise, low carrier transit time advantages of conventional silicon impact ionization devices while amplifying current from a photodiode of a different material. This is advantageous because ideal detection and multiplication regions cannot always be …

Performance Of Self-Encoded Spread Spectrum Under Worst-Case Jamming, Casey L. Deyle

Department of Computer Electronics and Engineering: Dissertations, Theses, and Student Research

Performance of Self-Encoded Spread Spectrum Under Worst-Case Jamming Casey Deyle, M.S University of Nebraska 2009 Advisor: Lim Nguyen Spread Spectrum Communications uses m-sequences (sometimes referred to as Pseudo Noise or PN sequences) modulated with a data signal to create a transmission signal that takes up more bandwidth than the original information signal. Self-Encoded Spread Spectrum (SESS) uses spreading codes generated by the transmitted signal, eliminating the need to synchronize m-sequences between the transmitter and receiver, thus making the channel more secure. This paper will discuss the performance of SESS system in Additive White Gaussian Noise (AWGN) and Rayleigh fading channels, …

Tunneling Between Carbon Nanofiber And Gold Electrodes, Toshishige Yamada, Tsutomu Saito, Makoto Suzuki, Patrick Wilhite, Xuhui Sun, Navid Akhavantafti, Drazen Fabris, Cary Y. Yang

Electrical and Computer Engineering

In a carbon nanofiber (CNF)-metal system such as a bridge between two gold electrodes, passing high current (current stressing) reduces the total resistance of the system (CNF resistance RCNF plus contact resistance Rc) by orders of magnitude. The role of current stressing is modeled as a reduction in the interfacial tunneling gap with transport characteristics attributed to tunneling between Au and CNF. The model predicts a reduction in Rc and gradual disappearance of the nonlinearity in the current-voltage (I-V) characteristics as Rc decreases. These results are consistent with measured I-V behavior.

Fast Block Matching Using Minkowski's Inequality, Jim Zong-Chang Lai, Yi-Ching Liaw, Shih-An Fong

Journal of Marine Science and Technology–Taiwan

In this paper, we present a fast block matching algorithm by making use of the Minkowski’s inequality. Combined with other fast block matching algorithms, our method can further reduce the computational complexity significantly with little PSNR degradation. Compared to the full search block matching algorithm, our approach can reduce the computing time by a factor of 6.4 to 21.5. Compared to MSEQ, which is a wellknown block matching algorithm preserving global optimality, our method can further reduce the corresponding computing time in average by 32.4%. The combination of our algorithm and the predictive search area approach for block motion estimation …

A Delay-Dependent Approach To Robust Stability For Uncertain Stochastic Neural Networks With Time-Varying Delay, Chien-Yu Lu, Chin-Wen Liao, Koan-Yuh Chang, Wen-Jer Chang

Journal of Marine Science and Technology–Taiwan

This paper investigates the global delay-dependent robust stability in the mean square for uncertain stochastic neural networks with time-varying delay. The activation functions are assumed to be globally Lipschitz continuous. Based on a linear matrix inequality approach, globally delay-dependent robust stability criterion is derived by introducing some relaxation matrices which, when chosen properly, lead to a less conservative result. Two numerical examples are given to illustrate the effectiveness of the method.

Optimal Heating And Energy Management For Slabs In A Reheating Furnace, Wei-Hsin Chen, Mu-Rong Lin, Tzong-Shyng Leu

Journal of Marine Science and Technology–Taiwan

Optimal heating for slabs in a reheating furnace is investigated numerically to aid in managing energy consumption of the reheating furnace in a hot strip mill, where an arctangent function is applied as the heating curve. Particular attention is paid to the relationship among the temperature uniformity, discharging target temperature and retention time of the slabs. The results indicate that the temperature difference between the slab surface and the core increases rapidly in the initial period and the maximum value of the temperature difference is close to the inflection point of the heating curve. After that, the internal temperature tends …

Estimation Model Of Transformer Iron Loss Using Neural Network, Tai-Ken Lu, Chien-Ta Yeh, Min-Doon Dirn

Journal of Marine Science and Technology–Taiwan

When we want to calculate the transformer iron loss in operation, in addition to considering the nonlinear hysteretic phenomenon of transformer itself and the natural unbalanced characteristic, the actual situation that the transformer is operated under three phase unbalance state should also be considered. This results in very non-regular change of the transformer iron loss, and the accuracy of the polynomial model that is commonly used to estimate the iron loss of the transformer in the past is thus reduced. Since neural network has parallel processing capability, which can process highly nonlinear function problem, hence, in this study, we try …

Effect Of Commutation Failures On Torsional Vibrations Of A Turbine Generator Nearby An Hvdc Link, Chi-Hshiung Lin

Journal of Marine Science and Technology–Taiwan

For an HVDC system, it is studied the torsional vibrations induced on the inverter side turbine generators due to a rectifier side ac faults. It is found there may be up to several times difference in the torsional torques induced at the turbine shafts and blades for the same fault, depending on the inverter commutation behavior. Further, if a single-phase-to-ground fault takes place with the commutation failure, it might cause a more serious impact on the turbine generator unit than a threephase-to-ground fault without commutation failure.

2010 Spring Engr333 Project Assignment, Matthew K. Heun

ENGR 333

The Spring 2010 ENGR333 project assessed options for the design of a redundant data center for the Calvin campus.

I asked the students “What would it take to build a redundant data center at Calvin that is 30% more energy efficient than the existing data center?”

Note: Because I was on sabbatical in Fall 2009, ENGR333 was moved to Spring 2010.

Customer

The customer for this project was Calvin’s VP for finance Henry DeVries.

Large Direct Repeats Flank Genomic Rearrangements Between A New Clinical Isolate Of Francisella Tularensis Subsp. Tularensis A1 And Schu S4, Ufuk Nalbantoglu, Khalid Sayood, Michael P. Dempsey, Peter C. Iwen, Stephen C. Francesconi, Ravi D. Barabote, Gary Xie, Thomas S. Brettin, Steven H. Hinrichs, Paul D. Fey

Department of Electrical and Computer Engineering: Faculty Publications

Francisella tularensis subspecies tularensis consists of two separate populations A1 and A2. This report describes the complete genome sequence of NE061598, an F. tularensis subspecies tularensis A1 isolated in 1998 from a human with clinical disease in Nebraska, United States of America. The genome sequence was compared to Schu S4, an F. tularensis subspecies tularensis A1a strain originally isolated in Ohio in 1941. It was determined that there were 25 nucleotide polymorphisms (22 SNPs and 3 indels) between Schu S4 and NE061598; two of these polymorphisms were in potential virulence loci. Pulsed-field gel electrophoresis analysis demonstrated that NE061598 was an …

Causal Rlgc( Ƒ ) Models For Transmission Lines From Measured S-Parameters, Jianmin Zhang, James L. Drewniak, David Pommerenke, Marina Koledintseva, Richard E. Dubroff, Wheling Cheng, Zhiping Yang, Qinghua B. Chen, Antonio Orlandi

Electrical and Computer Engineering Faculty Research & Creative Works

Frequency-dependent causal RLGC(f) models are proposed for single-ended and coupled transmission lines. Dielectric loss, dielectric dispersion, and skin-effect loss are taken into account. The dielectric substrate is described by the two-term Debye frequency dependence, and the transmission line conductors are of finite conductivity. In this paper, three frequency-dependent RLGC models are studied. One is the known frequency-dependent analytical RLGC model ( RLGC-I), the second is the RLGC(f) model (RLGC-II) proposed in this paper, and the third (RLGC-III) is same as the RLGC -II, but with causality enforced by the Hilbert transform in frequency domain. The causalities of the three RLGC …

Design, Construction And Load Testing Of The Bridge On Arnault Branch, Washington County, Missouri Using Innovative Technologies, Dongming Yan, Genda Chen, Nestore Galati, Sahra Sedigh

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The superstructure and instrumentation designs of a three-span bridge are presented in this report. The three spans include a precast box-girder bridge, a precast deck on steel girder and a precast deck on concrete girder. They were designed to compare the performance of various bridge decks reinforced with fiber reinforced polymers (FRP) through field instrumentations. A wireless monitoring system was designed to facilitate the collection of field data after the completion of bridge construction. The collected data will allow the study of FRP bars and stay-in-place FRP grid systems.

Recurrent Neural Networks Based Impedance Measurement Technique For Power Electronic Systems, Peng Xiao, Ganesh K. Venayagamoorthy, Keith Corzine, Jing Huang

Electrical and Computer Engineering Faculty Research & Creative Works

When designing and building power systems that contain power electronic switching sources and loads, system integrators must consider the frequency-dependent impedance characteristics at an interface to ensure system stability. Stability criteria have been developed in terms of source and load impedance, and it is often necessary to measure system impedance through experiments. Traditional injection-based impedance measurement techniques require multiple online testing that lead to many disadvantages, including prolonged test time, operating point variations, and impedance values at limited frequency points. The impedance identification method proposed in this paper greatly reduces online testing time by modeling the system with recurrent neural …

Reducing Common-Mode Voltage In Three-Phase Sine-Triangle Pwm With Interleaved Carriers, Jonathan W. Kimball, Maciej Jan Zawodniok

Electrical and Computer Engineering Faculty Research & Creative Works

Interleaving PWM waveforms is a proven method to reduce ripple in dc-dc converters. The present work explores interleaving for three-phase motor drives. Fourier analysis shows that interleaving the carriers in conventional uniform PWM significantly reduces the common-mode voltage. New DSP hardware supports interleaving directly with changes to just two registers at setup time, so no additional computation time is needed during operation. The common-mode voltage reduction ranges from 36% at full modulation to 67% when idling with zero modulation. Third harmonic injection slightly reduces the advantage (to 26% at full modulation). However, the maximum RMS common-mode voltage is still less …

A Novel Approach To Interarea Oscillation Damping By Unified Power Flow Controllers Utilizing Ultracapacitors, Mahyar Zarghami, Mariesa Crow, Jagannathan Sarangapani, Yilu Liu, Stan Atcitty

Electrical and Computer Engineering Faculty Research & Creative Works

This paper discusses a novel approach for damping interarea oscillations in a bulk power network using multiple unified power flow controllers (UPFCs) utilizing ultracapacitors, also known more generally as electrochemical capacitors (ECs). In this paper, a new control is introduced to mitigate interarea oscillations by directly controlling the UPFCs' sending and receiving bus voltages that better utilizes the stored energy in the ECs. The results of this controller are compared with and without ECs. The proposed control provides better interarea oscillation mitigation when applied to multiple UPFCs in the 118-bus IEEE test system.

Effects Of Hydrogen Pretreatment On Physical-Vapor-Deposited Nickel Catalyst For Multi-Walled Carbon Nanotube Growth, Benjamin L. Crossley, Mauricio Kossler, Ronald A. Coutu Jr., Lavern A. Starman, Peter J. Collins

Electrical and Computer Engineering Faculty Research and Publications

Physical vapor deposited nickel catalyst layers of 10, 50, 100, 200, 350, and 500 angstroms were granulated using hydrogen plasma for varying times to determine an effective carbon nanotube (CNT) growth process using microwave plasma enhanced CVD (MPECVD). Nickel was deposited via sputtering or evaporation. The catalyst granule size, density, and resulting CNTs were analyzed. Sputtered nickel of 50 angstroms with 5 minutes of hydrogen plasma pretreatment resulted in the most effective CNT growth.

A Theoretically Rigorous Full-Wave Finite-Element-Based Solution Of Maxwell's Equations From Dc To High Frequencies, Jianfang Zhu, Dan Jiao

Department of Electrical and Computer Engineering Technical Reports

It has been observed that finite element based solutions of full-wave Maxwell's equations break down at low frequencies. In this paper, we present a theoretically rigorous method to fundamentally eliminate the low-frequency breakdown problem. The key idea of this method is that the original frequency-dependent deterministic problem can be rigorously solved from a generalized eigenvalue problem that is frequency independent. In addition, we found that the zero eigenvalues of the generalized eigenvalue problem cannot be obtained as zeros because of finite machine precision. We hence correct the inexact zero eigenvalues to be exact zeros. The validity and accuracy of the …