Electrical and Computer Engineering Commons^™

Gaussian Beam Scattering From A Deterministic Rough Metal Surface, Qi Wang

Theses

A full-wave theory of plane wave scattering from rough surfaces called the Correction Current (CC) method was recently developed for the two-dimensional scatter problem that have a one-dimensional roughness profile. The method involves a primary field and radiation modes that are plane-wave-type fields that satisfy the boundary conditions at the rough surface. These fields do not satisfy Maxwell's source free equations, but they are forced to satisfy Maxwell's equations with distributed sources upon the introduction of fictitious volume currents distributions which correct for the field errors. Additionally, current sheet distributions are introduced which generate a radiation modal field that satisfies …

Electrochemical Catalysis: A Dft Study, Li Li, Zi-Dong Wei

Journal of Electrochemistry

In this review, we focus on achievements in electro-catalysis based on the density function theory study. The relationships among the electrode potential, electronic structure of catalysts and electro-catalytic activity are summarized in three parts: the adsorption and desorption of species, electron transfer, and stability of catalysts. The electrode potential and the electronic structure (d-band center or Fermi (HOMO) energy) of catalysts significantly influence the formation, adsorption and desorption of surface species on electrode. The electro-catalytic activity can be improved by modulating the electrode potential and electronic structure of catalysts.

Electrocatalytic Oxidation Of Formate On Pd-Cu/C - Effect Of Dealloying Pretreatment, Kun Jiang, Ye Wang, Tao Lin, Wen-Bin Cai

Journal of Electrochemistry

Carbon supported highly dispersed Pd-Cu nanoalloy catalyst toward formate electrooxidation is prepared via one-pot synthesis by using ethylene glycol as the reducing agent and sodium citrate as the stabilizer. The as-prepared catalyst is structurally characterized by TEM and XRD. The Cu dealloyment is carried out through repetitive potential cycling of the Pd-Cu/C catalyst in an acidic solution. The dealloying effect on the performance of the Pd-Cu/C is investigated by using cyclic voltammetry and chronoamperometry, and the surface structural change of Pd-Cu/C is probed by in situ ATR-IR measurement. The results show that the as-prepared Pd-Cu/C processes a better long-term stability …

Synthesis Of Silver Nanoparticles Supported On Graphene Quantum Dots For Oxygen Reduction Reaction, Jian Ju, Wei Chen

Journal of Electrochemistry

Silver-based catalysts have been extensively investigated as the platinum substituted catalysts due to their high catalytic efficiency, low cost and long-term durability. In this study, the surfactant-free silver nanoparticles supported on graphene quantum dots were synthesized through a facile approach without addition of any other protecting ligands and reducing agents. The “surface-clean” silver nanoparticles had remarkable electrocatalytic performance towards oxygen reduction reaction (ORR) with the most efficient four-electron transfer process. Compared with commercial Pt/C catalyst, the hybrid nanoparticles showed comparable catalytic performance for ORR but much higher tolerance to methanol. Such silver nanoparticles supported on graphene quantum dots may have …

Preparation And Lithium Storage Performance Of Sn-Snsb Nanoparticles, Yao Xiao, Jiao-Hong Wu, Qi Wang, Ling Huang, Jun-Tao Li, Shi-Gang Sun

Journal of Electrochemistry

Tin was widely studied as alternative anode material to carbon for lithium-ion batteries thanks to its much higher theoretical capacity. However, a pure tin electrode suffers severely from its poor cycleability due to mechanical fatigue caused by volume change during lithium insertion and extraction processes. Tin-based alloy may improve the cycleability property of tin electrode. In this article, we report facile synthesis of spherical Sn-SnSb nanopartciles using a simple solvent-thermal approach. It is amazing to find that the spherical Sn-SnSb nanoparticles can circumvent volume changes effectively during charge-discharge process. Electrochemical discharge/charge results show that the spherical Sn-SnSb nanoparticles electrode exhibits …

Electrochemical Fabrication Of Two-Dimensional Flower-Like Pt Nanostructures For Methanol Electrocatalytic Oxidation, Xia Wang, Jun Hu, Yong-Jun Li

Journal of Electrochemistry

Two-dimensional flower-like Pt nanostructures (2D FPNs) were fabricated on glassy carbon substrates by galvanostatical electrochemical technique. The electrolyte was the HAuCl₄ + HClO₄ aqueous solution without addition of any structure-directing organic reagent, which made as-prepared Pt nanostructures cleaner, exhibiting much higher reactivity. Scanning electron microscopic images revealed that 2D FPNs were spherical Pt nano-flowers constructed by the smallest building blocks, nano-leaves. The number density of spherical Pt nano-flowers can be tuned by controlling the electrodeposition time. High resolution transmission electron microscopic images indicated that each nano-leaf was formed by growing along Pt(111) direction. Electrocatalytic activities of as-prepared 2D …

A Sensitive And Label-Free Electrochemical Aptasensor Based On Signal Amplification Of Carbon Nanotubes, Chun-Yan Deng, Hui-Min Fan, Juan Xiang, Yuan-Jian Li

Journal of Electrochemistry

A label-free electrochemical sensing electrode for highly sensitive detection of adenosine was constructed based on the signal amplification of carbon nanotubes (CNTs). The change in the interfacial feature of the modified electrode was characterized by electrochemical impedance spectroscopy. Using [Ru(NH₃)₆]³⁺ as the signaling moiety, adenosine with concentrations as low as 0.027 nmol·L^-1 can be selectively detected. Additionally, the fabrication of this present aptasensor was simple, time-saving and cost-effective. Compared with other reported aptasensors, the proposed aptasensor had advantages of excellent sensitivity, selectivity and simplicity, which plays a potential role in development of aptasensor.

Investigation Of The Dynamics Of Photocarriers During Photoelectrochemical Water Splitting By Combination Of Photoelectrochemistry And Transient Absorption Spectroscopy, Wen-Hua Leng

Journal of Electrochemistry

Semiconductor photoelectrochemical hydrogen production is an important and promising technology for utilizing solar energy. The efficiency of hydrogen production depends on the efficiencies of separation and transport of photo-generated carriers. A deep understanding of the behavior of these processes has guiding significance for designing efficient solar hydrogen device. photoelectrochemical and transient absorption spectroscopy methods are powerful tool for studying the microscopic dynamics and mechanism of photocatalytic reaction. This review describes the part of the latest results of the author regarding the semiconductor photoelectrochemical hydrogen production obtained by these methods,and the problems and future research priorities in this field are proposed.

Effecting Of Dissolved Oxygen On Microbial Fuel Cells Based On Pseudomonas Aeruginosa, Chang-Li Cao, Li-Xiang Chen, Ran-Ran Wu, Ken-Lin Chang, Feng Zhao

Journal of Electrochemistry

In this work, the reaction between the electron shuttle secreted by Pseudomonas aeruginosa and anode was studied by measuring cyclic voltammogram and open circuit potential. The effect of dissolved oxygen on the oxidation reaction of anode was explored. It was demonstrated that the reaction was a diffusion-controlled and reversible process. The anode was a little affected when the dissolved oxygen of inocula was low (0 ~ 1.6 mg·L^-1). The polarization curves showed that the current output of microbial fuel cells decreased 7% with the impact of dissolved oxygen.

Formalization Of Matrix Theory In Hol4, Zhiping Shi, Yan Zhang, Zhenke Liu, Xinan Kang, Yong Guan, Jie Zhang, Xiaoyu Song

Electrical and Computer Engineering Faculty Publications and Presentations

Matrix theory plays an important role in modeling linear systems in engineering and science. To model and analyze the intricate behavior of complex systems, it is imperative to formalize matrix theory in a metalogic setting. This paper presents the higherorder logic (HOL) formalization of the vector space and matrix theory in the HOL4 theorem proving system. Formalized theories include formal definitions of real vectors and matrices, algebraic properties, and determinants, which are verified in HOL4. Two case studies, modeling and verifying composite two-port networks and state transfer equations, are presented to demonstrate the applicability and effectiveness of our work.

Recent Progress In The Mechanistic Understanding Of Formic Acid Oxidation On Pt Electrode, Jie Xu, Dao-Chuan Jiang, Dong Mei, Zheng-Da He, Yan-Xia Chen

Journal of Electrochemistry

This article reviews the recent progress in understanding of the mechanisms for formic acid oxidation on Pt electrode. There are two pathways for formic acid oxidation on Pt electrode: (1) Indirect Pathway through which HCOOH is oxidized to CO₂ through CO_ad intermediate. This pathway contributes only 1% of the total current; (2) Direct Pathway where HCOOH is oxidized directly to CO₂. The results from IR Spectroscopy, single-crystal electrochemistry and DFT calculation all support that the bridge-bonded formate is neither the intermediate of direct pathway nor the precursor for CO_ad formation in indirect pathway. Possible mechanism …

Preparation Of Pt-Tio2/Graphene Composites With High Catalytic Activity Towards Methanol Oxidation And Oxygen Reduction Reaction, Li Qi, Ying Yin, Wen-Guang Tu, Bing-Bing Wu, Zhao-Sheng Wang, Jian-Guo Liu, Jun Gu, Zhi-Gang Zou

Journal of Electrochemistry

A series of graphene-supported TiO₂ nanoparticles (TiO₂/G) with different TiO₂ contents were prepared by a facile hydrothermal method, and then the Pt-TiO₂/G catalysts were successfully prepared by reducing Pt-precursor with microwave technique. Compared with Pt-G catalysts, the catalytic performance toward oxygen reduction reaction (ORR) and methanol oxidation reaction (MOR) of Pt-TiO₂/G catalysts was improved due to the addition of TiO₂. However, the excessive TiO₂ would lead to a poor catalytic performance of Pt-TiO₂/G catalysts because of the low electrical conductivity of TiO₂.

Comparative Assessment Of Diverse Strategies For Malaria Vector Population Control Based On Measured Rates At Which Mosquitoes Utilize Targeted Resource Subsets, Gerry F. Killeen, Samson Sifael Kiware, Aklilu Seyoum, John E. Gimnig, George Corliss, Jennifer Stevenson, Christopher J. Drakeley, Nakul Chitnis

Electrical and Computer Engineering Faculty Research and Publications

Background

Eliminating malaria requires vector control interventions that dramatically reduce adult mosquito population densities and survival rates. Indoor applications of insecticidal nets and sprays are effective against an important minority of mosquito species that rely heavily upon human blood and habitations for survival. However, complementary approaches are needed to tackle a broader diversity of less human-specialized vectors by killing them at other resource targets.

Methods

Impacts of strategies that target insecticides to humans or animals can be rationalized in terms of biological coverage of blood resources, quantified as proportional coverage of all blood resources mosquito vectors utilize. Here, this concept …

Health Risks Caused By Wireless Technologies, Durreeshahwar Zafarahmed, Qurrat-Ul-Ain Zafarahmed

Journal of Undergraduate Research at Minnesota State University, Mankato

There are many health issues related to the use of cellular phones, wireless local area networks, and other devices that emit electromagnetic radiation (EMR). Some of these systems have become a part of our daily lives and many of us are in direct or indirect contact for extended period of times with these devices. However, the general public is unaware of the health risks associated with the use of these devices. Our research covers studies done by individuals as well as organizations on the harmful effects on the health of people from these devices and their claims. We also present …

Applied Energy Systems - Rudimentary Thermodynamics, Jim Mcgovern

Book/Book Chapters

This is a compact textbook for a module addressing rudimentary thermodynamics within the context of applied energy systems. It is at an introductory level for engineers or technologists. The book does not attempt to cover the principles of thermodynamics comprehensively. Rather, it provides a practical but theoretically sound foundation, linked to some key areas. Energy, heat and work are all introduced, as are units and dimensions. Ideal gases and properties of liquids and vapours are treated. Non-flow and steady flow processes are described. Simple theory is provided for pumps and for the reciprocating compressor. Rudimentary steam and refrigeration or heat …

Discussion On Eeoi Reduction Measures Based On Modern Management, Liying Song

Maritime Safety & Environment Management Dissertations (Dalian)

No abstract provided.

Digital Back End Development And Interference Mitigation Methods For Radio Telescopes With Phased-Array Feeds, Richard Allen Black

Theses and Dissertations

The Brigham Young University (BYU) Radio Astronomy group, in collaboration with Cornell University, the University of Massachusetts, and the National Radio Astronomy Observatory (NRAO), have in recent years developed and deployed PAF systems that demonstrated the advantages of PAFs for astronomy. However, these systems lacked the necessary bandwidth and acquisition times to be scientifically viable. This thesis outlines the development of a 20-MHz bandwidth system that can acquire for much longer periods of time and across much larger bandwidths than previous BYU systems. A report of the deployment of this system on the 305-meter reflector at the Arecibo Observatory in …

Analysis Of An All Optical De-Multiplexer Architecture Utilizing Bevel Design For Spatially Multiplexed Optical Fiber Communication Systems, Syed H. Murshid, Michael F. Finch, Gregory L. Lovell

Electrical Engineering and Computer Science Faculty Publications

Spatial domain multiplexing (SDM) is a system that allows multiple channels of light to traverse a single fiber, utilizing separate spatial regions inside the carrier fiber, thereby applying a new degree of photon freedom for optical fiber communications. These channels follow a helical pattern, the screen projection of which is viewable as concentric rings at the output end of the system. The MIMO nature of the SDM system implies that a typical pin-diode or APD will be unable to distinguish between these channels, as the diode will interpret the combination of the SDM signals from all channels as a single …

Circular Polarized Leaky Wave Surface, Franklin Muriuki Manene, Brian A. Lail, Edward C. Kinzel

Electrical Engineering and Computer Science Faculty Publications

A circular polarized (CP) infrared (IR) leaky wave surface design is presented. The metasurface consists of an array of rectangular patches connected by microstrip and operating over the long-wave infrared (LWIR) spectrum with directional wave emission and absorption. The surface is composed of periodically aligned arrays of sub-wavelength metal patches separated from a ground plane by a dielectric slab. The design combines the features of the conventional patch and leaky wave antenna leading to a metasurface that preferentially emits CP IR radiation by use of axial asymmetrical unit cells. This is a deviation from reported structures that mainly employ a …

Mode Splitting And Resonant Coupling Between A Slot Metasurface And Pmma, Michael F. Finch, Brian A. Lail

Electrical Engineering and Computer Science Faculty Publications

A slot metasurface (metascreen) designed to have resonance that couples with the 1733 cmˉ¹ absorption peak of the C=O molecular bond of PMMA (polymethyl methacrylate) is presented. The metasurface is made of a gold layer perforated with periodically-placed slots and stood off above a reflective ground plane with silicon substrate. The metasurface is modeled using ANSYS HFSS and including measured optical properties for gold, silicon and PMMA in the infrared spectrum. PMMA forms a thin overcoat and exhibits a strong absorption resonance at wavenumber 1733 cmˉ¹. Coupling between the metasurface and PMMA is observed via normal mode splitting. Mode splitting …

Concentric Circles Based Simple Optical Landing Aid For Vertical Takeoff And Landing Aircrafts, Syed H. Murshid, Rayan Enaya

Electrical Engineering and Computer Science Faculty Publications

Vertical takeoff and landing (VTOL) aircrafts such as helicopters and drones, add a flexible degree of operation to airborne vehicles. In order to operate these devices in low light situations, where it is difficult to determine slope of the landing surface, a lightweight and standalone device is proposed here. This small optical device can be easily integrated into current VTOL systems. An optical projector consisting of low power, light weight, solid state laser along with minimal optics is utilized to illuminate the landing surface with donut shaped circles and coaxial centralized dot. This device can placed anywhere on the aircraft …

Analysis Of Spatial Domain Multiplexing/Space Division Multiplexing (Sdm) Based Hybrid Architectures Operating In Tandem With Wavelength Division Multiplexing, Syed H. Murshid, Gregory L. Lovell, Bilas Chowdhury, Arnob Hridoy, Gurinder Parhar, Abhijit Chakravarty, Saud F. Alanzi

Electrical Engineering and Computer Science Faculty Publications

Spatial domain multiplexing (SDM) also known as space division multiplexing adds a new degree of photon freedom to existing optical fiber multiplexing techniques by allocating separate radial locations to different MIMO channels as a function of the input launch angle. These independent MIMO channels remain confined to the designated location while traversing the length of the carrier fiber, due to helical propagation of light inside the fiber core. The SDM technique can be used in tandem with other multiplexing techniques, such as time division multiplexing (TDM), and wavelength division multiplexing in hybrid optical communication schemes, to achieve higher optical fiber …

Universal Liquid Level Sensor Employing Fresnel Coefficient Based Discrete Fiber Optic Measurement Technique, Syed H. Murshid

Electrical Engineering and Computer Science Faculty Publications

A compact and light weight liquid-level-measuring system based on fiber-optics sensor technology is presented as alternative to systems based on float gauges and other conventional level sensors for liquids that pose fire, corrosion and explosion hazards. These Fresnel reflection based fiber-optic sensors are inherently safer because they do not include electrical connections inside fuel/chemical tanks, and they exploit changes in internal reflection of guided electromagnetic modes as a result of contact between the outer surface of optical fiber and a liquid. Discrete changes in light transmission/reflection are used to indicate that liquid has come into contact with a suitably designed …

An Order Of Magnitude Improvement In Optical Fiber Bandwidth Using Spatial Domain Multiplexing/Space Division Multiplexing (Sdm) In Conjunction With Orbital Angular Momentum (Oam), Syed H. Murshid, Saud F. Alanzi, Arnob Hridoy, Gregory L. Lovell, Gurinder Parhar, Abhijit Chakravarty, Bilas Chowdhury

Electrical Engineering and Computer Science Faculty Publications

Spatial Domain Multiplexing/Space Division Multiplexing (SDM) can increase the bandwidth of existing and futuristic optical fibers by an order of magnitude or more. In the SDM technique, we launch multiple single mode pigtail laser sources of same wavelength into a carrier fiber at different angles. The launching angles decide the output of the carrier fiber by allocating separate spatial locations for each channel. Each channel follows a helical trajectory while traversing the length of the carrier fiber, thereby allowing spatial reuse of optical frequencies. In this endeavor we launch light from five different single mode pigtail laser sources at different …

Analysis And Comparison Of Experimental And Simulated Results For An Omnidirectional Free Space Optical Receiver Architecture, Syed H. Murshid, Gregory L. Lovell, Michael F. Finch

Electrical Engineering and Computer Science Faculty Publications

Lasercomm or Free Space Optical (FSO) communication has the potential to provide fiber optic data rates without the need for wired physical connectivity. This paper investigates the feasibility of an Omnidirectional FSO (O-FSO) communications link that utilizes fiber bundles for improved omni-directionality and compares experimental data with modeled results. Current state of the art O-FSO link ranges are limited to 100 meters or so, with data rates of only a few 100 kbits/sec. The proposed architecture is formed from commercially available fiber bundle that collects omnidirectional light due to the hemispheric nature of the fiber bundle by exploiting the acceptance …

Optimization Of Electrical Discharge Machining Parameters For Niti Shape Memory Alloy By Using The Taguchi Method, Saeed Daneshmand, Ehsan Farahmand Kahrizi, Ali Akbar Lotfineyestanak, Vahid Monfared

Journal of Marine Science and Technology–Taiwan

Electrical discharge machining (EDM) is among the most essential nontraditional machining processes. Material removal rate (MRR) and surface roughness are the two main parameters applied in this method. A desired surface roughness can be achieved at the maximal MRR by selecting the optimal input parameters. Because of the mechanical properties and hardness of shape-memory nickel titanium (NiTi) alloy, material can be removed using an EDM method. NiTi alloy is widely used in marine science and aerospace industries. Surface roughness is a critical parameter affecting the machining of this alloy. This study examined the effect the input parameters (pulse current, gap …

Added Mass Computation For Control Of An Open-Frame Remotely-Operated Vehicle: Application Using Wamit And Matlab, You-Hong Eng, Cheng-Siong Chin, Michael Wai-Shing Lau

Journal of Marine Science and Technology–Taiwan

In this paper, numerical modeling and testing of a complexshaped remotely-operated vehicle (ROV) are shown. The paper emphasizes on systematic modeling of hydrodynamic added mass using computational fluid dynamic software WAMITTM on the open frame ROV that is not commonly applied in practice. From initial design and prototype testing, a small-scale test using a free-decaying experiment is used to verify the theoretical models obtained from WAMITTM. Simulation results have shown to coincide with the experimental tests. The proposed method is able to determine the hydrodynamic added mass coefficients of the open frame ROV.

Intelligent Dynamic Acquisition Learning Fuzzy Modeling Systems Design, Hsuan-Ming Feng, Ching-Yi Chen

Journal of Marine Science and Technology–Taiwan

Secretary General, Taiwan Group on Earth Observations, Taiwan, R.O.C

Robust Adaptive Motion Control With Environmental Disturbance Rejection For Perturbed Underwater Vehicles, Hamid Reza Koofigar

Journal of Marine Science and Technology–Taiwan

This paper addresses the motion control problem of autonomous underwater vehicles (AUVs) perturbed by unknown hydrodynamic coefficients, unmodelled dynamics and environmental disturbances. The proposed algorithm consists of an adaptive subcontroller to tackle the parametric uncertainties and a robust term to vanish the effects of unstructured uncertainties and disturbances. The resulting robust adaptive controller ensures the convergence of tracking error, without any assumption on the upper bound of perturbations in the design procedure. The closed loop stability is shown, using the Lyapunov stability theorem, and verified by various simulations.

Effects Of Power System Stabilizer On Inter-Area Oscillations In Vietnam Power System, Van-Dien Doan, Ta-Hsiu Tseng, Pei-Hwa Huang

Journal of Marine Science and Technology–Taiwan

The main objective of this paper is to report a preliminary study of the effects of the power system stabilizer on the small-signal stability and the damping of low-frequency oscillations of the Vietnam power system which is under fast development and has a longitudinal grid pattern. Spontaneous low-frequency oscillations are potential to occur in the exchange of regional power flow of a power system with longitudinal network structure under normal operation. The method of eigen-analysis is utilized to perform the study of the inter-area oscillations with an emphasis on the oscillation mode with low frequency and light damping. The eigenvalues, …