Electrical and Computer Engineering Commons^™

Electrocatalytic Reduction Of L-Cystine At Pb/Nanotio2 Film Electrode, Dao-Bao Chu, Feng Wang, Ying Xiao, Xue-Jiao Zhang

Journal of Electrochemistry

The nanoporous Ti-based TiO₂ films electrodes modified with Pb particles(Pb/nanoTiO₂) were prepared by using anodization and potentiostatic electro-deposition.The optimum deposition conditions were determined by comparing with various deposition potentials and time.The SEM analyses indicated that the TiO₂ films were homogeneous nanoporous structure,and the Pb particles well dispersed on the TiO₂ films.The L-cystine electrocatalytic activity reduction on the Pb/nanoTiO₂ film electrodes was investigated by cyclic voltammetry and Chronoamperometric curves.The results showed that this type of the electrode posseses high acticity and stability.

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.

Throughput Optimization In Mpr-Capable Multi-Hop Wireless Networks, Jorge Crichigno

Electrical and Computer Engineering ETDs

Recent advances in the physical layer have enabled the simultaneous reception of multiple packets by a node in wireless networks. This capability has the potential of improving the performance of multi-hop wireless networks by a logarithmic factor with respect to current technologies. However, to fully exploit multiple packet reception (MPR) capability, new routing and scheduling schemes must be designed. These schemes need to reformulate a historically underlying assumption in wireless networks which states that any concurrent transmission of two or more packets results in a collision and failure of all packet receptions. In this work, we present a generalized model …

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 …

The Value Of Concentrating Solar Power And Thermal Energy Storage, Ramteen Sioshansi, Paul Denholm

Publications (E)

This paper examines the value of concentrating solar power (CSP) and thermal energy storage (TES) in four regions in the southwestern United States. Our analysis shows that TES can increase the value of CSP by allowing more thermal energy from a CSP plant’s solar field to be used, by allowing a CSP plant to accommodate a larger solar field, and by allowing CSP generation to be shifted to hours with higher energy prices. We analyze the sensitivity of CSP value to a number of factors, including the optimization period, price and solar forecasting, ancillary service sales, capacity value and dry …

Doe Request For Information (Rfi) De-Foa-0000153 Pv Manufacturing Initiative: Summary Report, National Renewable Energy Laboratory

Publications (E)

Clean Cities hosts a collection of tools on the exploring concepts for a “PV Manufacturing Initiative” to facilitate the development of a strong photovoltaic (PV) manufacturing industry in the United States. As an integral part this effort, and to inform the creation of a new funding opportunity in this area, DOE sought feedback from the PV industry.

This document summarizes the results of the PV Manufacturing Request for Information (RFI), DE-FOA-0000153. (See Attachment 1.) The RFI was posted on http://www.grants.gov on 4 September 2009 and the NREL Web site on 9 September 2009. Respondents were asked to submit RFI inputs …

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 …

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.

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 …

H-Matrix-Based Fast Direct Finite Element Solver For Large-Scale Electromagnetic Analysis, Haixin Liu, Dan Jiao

Department of Electrical and Computer Engineering Technical Reports

In this work, we prove that the sparse matrix resulting from a finite-element-based analysis of electrodynamic problems can be represented by an H-matrix without any approximation, and the inverse of this sparse matrix has a data-sparse H-matrix approximation with error well controlled. Based on this proof, we develop an H-matrix-based direct finite-element solver of O(kNlogN) memory complexity and O(k2Nlog2N) time complexity for solving electromagnetic problems, where k is a small variable that is adaptively determined based on accuracy requirements, and N is the number of unknowns. Both inversebased and LU-based direct solutions are developed. The LU-based solution is further accelerated …

Statistical Approach For Yield Optimization For Minimum Energy Operation In Subthreshold Circuits Considering Variability Issues, Md. Waliullah Khan Nomani, Mohab Anis, Goutam Koley

Faculty Publications

The supply voltage (V-dd) and threshold voltage (V-th) are two significant design variables that directly impact the performance and power consumption of circuits. The scaling of these voltages has become a popular option to satisfy performance and low power requirements. Subthreshold operation is a compelling approach for energy-constrained applications where processor speed is less important. However, subthreshold designs show dramatically increased sensitivity to process variations due to the exponential relationship of subthreshold drive current with V-th variation and drastically growing leakage power. If there is uncertainty in the value of the threshold or supply voltage, the power advantages of this …

Constrained Kalman Filtering Via Density Function Truncation For Turbofan Engine Health Estimation, Daniel J. Simon, Donald L. Simon

Electrical and Computer Engineering Faculty Publications

Kalman filters are often used to estimate the state variables of a dynamic system. However, in the application of Kalman filters some known signal information is often either ignored or dealt with heuristically. For instance, state variable constraints (which may be based on physical considerations) are often neglected because they do not fit easily into the structure of the Kalman filter. This article develops an analytic method of incorporating state variable inequality constraints in the Kalman filter. The resultant filter truncates the probability density function (PDF) of the Kalman filter estimate at the known constraints and then computes the constrained …