Digital Commons Network^™

Progress In Research For Biofuel Cell, Yue Bao, Xia-Qin Wu

Journal of Electrochemistry

In this article, research progresses of the biofuel cell in recent years were summarized. The operation principle and classification of the biofuel cells were described. The role of the mediator for promoting electron transfer in biofuel cells and the techniques for improving the electric properties of biofuel cells, such as output potential, were discussed with some attracting research instances. Finally, the choke points for research of biofuel cell were explored, and the application prospect of biofuel cells was forecasted.

Preparation, Structure And Electrochemical Hydrogenation Of Carbon Nanotubes Supported Platinum Catalysts, Qing-Gang He, Xiao-Zi Yuan, Xian-Xia Yuan, Zi-Feng Ma

Journal of Electrochemistry

In this paper, Pt/CNTs catalyst was prepared and its electrocatalytic property was studied by obtaining cycling voltammetry curves (C-V) and Tafel curves. In addition, the XRD,XPS and TEM tests were carried out to determine the structure and composition of the catalysts. It can be found that the platinum loading has been increased significantly using a carbon nanotubes support. Dispersion of Platinum was better and gave more active sites. The electrochemical characteristic of Pt/CNTs was also more desirable than that of Pt/C catalys t(Johnson Matthey). In conclusion, carbon nanotubes can played a conspicuous role in "electrogenerative" processes of PEMFC hydrogenation reactor.

The Interaction In Doping Lithium Of Carbonaneous Anode In Lithium Ion Battery, Chang-Guo Chen, Hong-Min Zhang, Jia Chen, Dan-Mei Yu

Journal of Electrochemistry

The quantum chemical DV-X_α method was used to calculate the lithium-doped models from one-Li-dopant to LiC₆ and LiC₂. It was found that Li⁺ has an tendency to attract electrons from the carbon plane through the C₆ hexagons lying above or below it by the graph of charge-density difference. It was shown that LiC₆ can exist steadily,while LiC₂ can not exist steadily.

Study On Determination Of Iodine Ion At Chitosan Modified Glassy Carbon Electrode, Bin Liu, Xiang-Ying Sun, Jin-Rui Xu

Journal of Electrochemistry

In this paper, a chitosan modified glassy carbon electrode was prepared by the method of covalent-bond reaction, and the anodic stripping voltammetric characteristics of iodine on the modified electrode was studied. The results showed that the modified electrode has higher adsorption and selectivity for I^- , and the sensitivity for I^-  has been much improved in 0.1 mol·L^-1 KH₂PO₄ solution (pH=4.0). The anodic stripping peak current of I^- on the modified electrode varied linearly with I^-  concentration in the range of 2.0×10^-6～2.0×10^-3 mol·L^-1, and the detection limit …

Electrochemical Synthesis Of Ferrate(Vi) By Anodic Oxidation, Jia-Ju Xu, Jian-Ming Wang, Wei-Hua Yang, Cheng Chen, Jian-Qing Zhang

Journal of Electrochemistry

The ferrate(Ⅵ) was synthesized by electrochemical anodic oxidation. The effects of preparation conditions on the current yield of ferrate(VI) synthesis have been studied in this work. The experimental results showed that grey cast iron as an anodic material is suitable for electrochemical synthesis and NaOH solution as an electrolyte results in a higher current yield than KOH solution. The highest current yield was obtained at a current density (4.54) mA·cm^-2, temperature 20 ℃ and 14 mol·dm^-3 NaOH. In this case, a current yield of 68.5% was obtained by electrolysis for 1 h.

Studies On The Mechanism Of Electroreduction Of Oxalic Acid, Yu-Zhan Li, Xin Liu, Rui-Sheng Hu, Deng-Ping Gu

Journal of Electrochemistry

The electroreduction mechanism of oxalic acid on Pb electrode in Na₂SO₄ solution were investigated using high scan rate cyclic voltammetry and chronoamperometry. The dynamic parameters for the first step electron transter reaction of oxalic acid electroreduction by were determined. The corresponding reduction peak potentials of oxalic acid, glyoxylic acid and glycolic acid in the cyclic voltammogranis obtained in the same condition were compared, and the intermediate reduction products of oxalic acid were suggested. The results showed that oxalic acid is weakly absorbed on the lead electrode.

Template Synthesis Of Highly Ordered Monocrystalline Metal Nanowire Arrays By A Two-Step Ac Electrodeposition, Juan Xiang, Jing-Hua Tian, Zi-Mian Ni, Zhi-Feng Huang, Bo Liu, Zhong-Qun Tian

Journal of Electrochemistry

The monocrystalline metal nanowire arrays were prepared by using a two-step AC electrodeposition in porous anodic aluminum oxide (AAO) template. The growth mechanism of nanowires was discussed. As a result, it has been found that the second voltage pulse has a considerable effect on the pore-filling ratio, the uniformity and the crystal structure, whereas the initial voltage pulse affects only the pore-filling ratio. Using the two-step AC electrodeposition, a highly ordered monocrystalline metal nanowire arrays with a pore-filling ration above 95% can be easily obtained.

Electrochemical Character Of Water Containing Gel Electrolyte And Its Preliminary Examination In Lithium Water Cell, Jing-Dong Liu, Wen-Ji Wang, Xin-Zheng Yi

Journal of Electrochemistry

AC impedance technique has been used to characterize the system of poly(methyl acrylic acid)-poly(methyl acrylic lithiumate)-glycerol (referred to as GPE).The results showed that the conductivity of GPE increased with increasing both temperature and its water content.The glass transition temperature of GPE polymer could be lowered by water. Its conducting characteristic was just like liquid electrolyte,The electrolysis of GPE was almost the same as the electrolysis of water. Its composition voltage was about 1.50V. The GPE has been used to manufacture lithium water cell. When the graphite was used as cathode, the cell could discharge continuously for 2 hours under constant …

Statistical Image Differences, Degradation Features, And Character Distance Metrics, Elisa Barney Smith, Xiaohui Qiu

Electrical and Computer Engineering Faculty Publications and Presentations

Document image quality is degraded through processes such as scanning, printing, and photocopying. The resulting bilevel image degradations can be categorized based either on observable degradation features or on degradation model parameters. The image degradation features can be related mathematically to model parameters. In this paper we statistically compare pairs of populations of degraded character images created with different model parameters. The probability that the character populations were degraded by the same model parameters correlates with the relationship between observable degradation features and the model parameters. Two metrics of character difference are used: Hamming distance and moment feature distance. Knowledge …

Pulse Regulation Control Technique For Flyback Converter, Mehdi Ferdowsi, Ali Emadi

Electrical and Computer Engineering Faculty Research & Creative Works

Pulse regulation, a fixed frequency control technique, is introduced and applied to flyback converter operating in discontinuous conduction mode (DCM). The control parameters are designed in a way that the converter operates as close as possible to the critical conduction mode. In contrast to the conventional pulse width modulation (PWM) control scheme, the principal idea of pulse regulation is to achieve output voltage regulation using high and low-power pulses. Pulse regulation is simple, cost effective, and enjoys a fast dynamic response. The proposed technique is applicable to any converter operating in DCM. However, this work mainly focuses on flyback topology. …

Common-Mode Current Due To A Trace Near A Pcb Edge And Its Suppression By A Guard Band, Yoshiki Kayano, Motoshi Tanaka, James L. Drewniak, Hiroshi Inoue

Electrical and Computer Engineering Faculty Research & Creative Works

The common-mode (CM) current due to a trace near a printed circuit board (PCB) edge, and its suppression by a guard band have been studied experimentally and with finite-difference time-domain (FDTD) modeling. As the guard band, copper tape is connected along the entire edge of the ground plane. First, a PCB electromagnetic interference (EMI) coupling path that results from the nonzero impedance of the PCB ground plane is discussed. As the trace is moved closer to the PCB edge, the CM current increases. Then, the effect of the guard band on the CM current is detailed. A guard band parallel …

An Efficient Multirate Simulation Technique For Power-Electronic-Based Systems, Steven D. Pekarek, Oleg Wasynczuk, Eric A. Walters, Juri V. Jatskevich, Charles E. Lucas, Ning Wu, Peter T. Lamm

Electrical and Computer Engineering Faculty Research & Creative Works

A novel multirate method of simulating power-electronic-Based systems containing a wide range of time scales is presented. in this method, any suitable integration algorithm, with fixed or variable time-step, can be applied to the fast and/or slow subsystems. the subsystems exchange coupling variables at a communication interval that can be fixed or varied dynamically depending upon the state of the system variables. the proposed multirate method is applied to two example power systems that include power-electronic subsystems. Increases in simulation speed of 183-281% over established single-rate integration algorithms are demonstrated.

Wide-Band/Dual-Band Packaged Antenna For 5-6 Ghz Wlan Application, Mohammod Ali, Tuangsit Sittironnarit, Huan-Sheng Hwang, Robert A. Sadler, Gerard James Hayes

Faculty Publications

A wide-band/dual-band packaged antenna is proposed for wireless local-area network (WLAN) applications in the 5.15-5.35 GHz and 5.725-5.825 GHz frequency range. The antenna is internal to the housing of a personal digital assistant, such as a Palm organizer, and has the dimensions of 28 by 9 by 3 ram on an FR4 substrate. The antenna meets or exceeds the bandwidth requirements for the dual-band IEEE 802.11a WLAN applications (5.15-5.35 GHz and 5.725-5.825 GHz) within 2:1 voltage standing-wave ratio.

Laboratory Project In Wireless Fsk Receiver Design, Michael A. Jensen, Cynthia Fuse, Raymond Woodward

Faculty Publications

This paper describes a wireless local area network laboratory project that provides senior and first-year graduate students in microwave engineering courses the opportunity to design, build, and test several passive microstrip components and integrate them into a working system. Students design filters, couplers, amplifiers, diode detectors, quarter-wave transformers, antennas, and stub matching networks in weekly labs that parallel-lectures in a one-semester microwave engineering course. This paper also describes simple inexpensive prototyping and testing methods that have been used in this course. Laboratory materials and technical details of the design are provided on the web for students and educators.

Adaptive Learning For Event Modeling And Pattern Classification, Shuangshuang Dai

Dissertations

It is crucial to detect, characterize and model events of interest in a new propulsion system. As technology advances, the amount of data being generated increases significantly with respect to time. This increase substantially strains our ability to interpret the data at an equivalent rate. It demands efficient methodologies and algorithms in the development of automated event modeling and pattern recognition to detect and characterize events of interest and correlate them to the system performance. The fact that the information required to properly evaluate system performance and health is seldom known in advance further exacerbates this issue.

Event modeling and …

Multi-Spectral Light Interaction Modeling And Imaging Of Skin Lesions, Sachin Vidyanand Patwardhan

Dissertations

Nevoscope as a diagnostic tool for melanoma was evaluated using a white light source with promising results. Information about the lesion depth and its structure will further improve the sensitivity and specificity of melanoma diagnosis. Wavelength-dependent variable penetration power of monochromatic light in the trans-illumination imaging using the Nevoscope can be used to obtain this information. Optimal selection of wavelengths for multi-spectral imaging requires light-tissue interaction modeling. For this, three-dimensional wavelength dependent voxel-based models of skin lesions with different depths are proposed. A Monte Carlo simulation algorithm (MCSVL) is developed in MATLAB and the tissue models are simulated using the …

Ip-Based Virtual Private Networks And Proportional Quality Of Service Differentiation, Jingdi Zeng

Dissertations

IP-based virtual private networks (VPNs) have the potential of delivering cost-effective, secure, and private network-like services. Having surveyed current enabling techniques, an overall picture of IP VPN implementations is presented.

In order to provision the equivalent quality of service (QoS) of legacy connection-oriented layer 2 VPNs (e.g., Frame Relay and ATM), IP VPNs have to overcome the intrinsically best effort characteristics of the Internet. Subsequently, a hierarchical QoS guarantee framework for IP VPNs is proposed, stitching together development progresses from recent research and engineering work.

To differentiate IP VPN QoS, the proportional QoS differentiation model, whose QoS specification granularity compromises …

Studies In Multiple-Antenna Wireless Communications, Christian Bruce Peel

Theses and Dissertations

Wireless communications systems are used today in a variety of milieux, with a recurring theme: users and applications regularly require higher throughput. Multiple antennas enable higher throughput and/or more robust performance than single-antenna communications, with no increase in power or frequency bandwidth. Systems are required which achieve the full potential of this "space-time" communication channel under the significant challenges of time-varying fading, multiple users, and the choice of appropriate coding schemes. This dissertation is focused on solutions to these problems. For the single-user case, there are many well-known coding techniques available; in the first part of this dissertation, the performance …

The Removal Of Motion Artifacts From Non-Invasive Blood Pressure Measurements, Paresh Thakkar

Electronic Theses and Dissertations

Modern Automatic Blood Pressure Measurement Techniques are based on measuring the cuff pressure and on sensing the pulsatile amplitude variations. These measurements are very sensitive to motion of the patient or the surroundings where the patient is. The slightest unexpected movements could offset the readings of the automatic Blood Pressure meter by a large amount or render the readings totally meaningless. Every effort must be taken to avoid subjecting the body of the patient or the patient's surroundings to motion for obtaining a reliable reading. But there are situations in which we need Blood Pressure Measurements with the patient or …

Raindrop Size Distribution Retrieval And Evaluation Using An S-Band Radar Profiler, Fang Fang

Electronic Theses and Dissertations

Vertical pointing Doppler radar profilers are used to explore the vertical structure of precipitation cloud systems and to provide validation information for use in weather research. In this thesis, a theoretical radar rain-backscatter model was developed to simulate profiler Doppler spectra as a function of assumed rain parameters, of which the raindrop size distribution (DSD) is the fundamental quantity used to describe the characteristics of rain. Also, profiler observations during stratiform rain are analyzed to retrieve the corresponding rain DSD’s. In particular, a gamma distribution model is introduced, which uses Rayleigh scattering portion of the Doppler velocity spectrum to estimate …

Analysis And Implementation Of A Synchronous Buck Converter Used As An Intermediate Stage Of An Hid Ballast, Sergey V. Vernyuk

ETD Archive

The contribution of this thesis is the analysis of a Synchronous Buck converter, used as the second stage (which controls the current through the lamp, and consequently, the lamp power) in a 3-stage High-Intensity Discharge (HID) ballast. Where previously standard Buck converters were used, this new application of the Synchronous Buck converter to a medium-power lighting ballast improves efficiency by operating the converter in a new, modified critical-conduction mode to achieve soft-switching and improve efficiency significantly. The converter and 2-loop controller will be analyzed in the three HID lamp modes of operation: open circuit, short circuit, and power control mode. …

Using Information Technology To Enhance Control Engineering Education: Some Experiences, Aidan O'Dwyer

Conference papers

In the past decade, the use of computer based design and analysis tools, such as MATLAB/SIMULINK, has revolutionised practice in Control Engineering. Concepts that were previously only understandable after sustained mathematical analysis or experimental work may now be readily simulated on the computer. Over the past four years, the author has experimented with the use of MATLAB/SIMULINK, in the lecture and laboratory environment, with degree and taught masters students in control engineering at Dublin Institute of Technology (DIT). It has been found that the tool helps to increase student understanding of challenging topics, to act as motivation to further exploration …

Energy Aware Design And Analysis For Synchronous And Asynchronous Circuits, Jia Di

Retrospective Theses and Dissertations

Power dissipation has become a major concern for IC designers. Various low power design techniques have been developed for synchronous circuits. Asynchronous circuits, however. have gained more interests recently due to their benefits in lower noise, easy timing control, etc. But few publications on energy reduction techniques for asynchronous logic are available.

Power awareness indicates the ability of the system power to scale with changing conditions and quality requirements. Scalability is an important figure-of-merit since it allows the end user to implement operational policy. just like the user of mobile multimedia equipment needs to select between better quality and longer …

Modified Sierpinski Fractal Antenna, Tripti Luintel

Electronic Theses and Dissertations

Fractal antennas have the potential to provide multi-band solution through the property of self similarity that the fractal shape possess. This thesis deals with some modifications of the original Sierpinski fractal patch antenna, providing additional parameters to optimize in order to get the required radiation characteristics. A systematic study of the original Sierpinski monopole was done to gain an insight on the operation and multi-band behavior of the antenna and a similar study was done to find out why the patch version of Sierpinski lacks multi-band behavior. A Sierpinski antenna is designed by merging a grid and the fractal restoring …

Evaluation Of A Microwave Radiative Transfer Model For Calculating Sat, Simonetta Thompson

Electronic Theses and Dissertations

Remote sensing is the process of gathering and analyzing information about the earth's ocean, land and atmosphere using electromagnetic "wireless" techniques. Mathematical models, known as Radiative Transfer Models (RTM), are developed to calculate the observed radiance (brightness temperature) seen by the remote sensor. The RTM calculated brightness temperature is a function of fourteen environmental parameters, including atmospheric profiles of temperature, pressure and moisture, sea surface temperature, and cloud liquid water. Input parameters to the RTM model include data from NOAA Centers for Environmental Prediction (NCEP), Reynolds weekly Sea Surface Temperature and National Ocean Data Center (NODC) WOA98 Ocean Salinity and …

Thermal Management, Beam Control,And Packaging Designs For High Power, Te-Yuan Chung

Electronic Theses and Dissertations

Several novel techniques for controlling, managing and utilizing high power diode lasers are described. Low pressure water spray cooling for a high heat flux system is developed and proven to be an ideal cooling method for high power diode laser arrays. In order to enable better thermal and optical performance of diode laser arrays, a new and simple optical element, the beam control prism, is invented. It provides the ability to accomplish beam shaping and beam tilting at the same time. Several low thermal resistance diode packaging designs using beam control prisms are proposed, studied and produced. Two pump cavity …

Autonomous Environmental Mapping In Multi-Agent Uav Systems, Linus Jan Luotsinen

Electronic Theses and Dissertations

UAV units are by many researchers and aviation specialists considered the future and cutting edge of modern flight technology. This thesis discusses methods for efficient autonomous environmental mapping in a multi-agent domain. An algorithm that emphasizes on team work by sharing the agents local map information and exploration intentions is presented as a solution to the mapping problem. General theories on how to model and implement rational autonomous behaviour for UAV agents are presented. Three different human and tactical behaviour modeling techniques are evaluated. The author found the CxBR paradigm to be the most interesting approach. Also, in order to …

Performance Analysis Of Low-Power, Short-Range Wireless Transceivers, Usha Neupane

Electronic Theses and Dissertations

To address the various emerging standards like BluetoothTM, Home RF, Wi-fiTM (IEEE 802.11), ZigBeeTM etc., in the field of wireless communications, different transceivers have been designed to operate at various frequencies such as 450 MHz, 902-920 MHz, 2.4 GHz, all part of designated ISM band. Though, the wireless systems have become more reliable, compact and easy to develop than before, a detailed performance analysis and characterization of the devices should be done. This report details the performance analysis and characterization of a popular binary FSK transceiver TRF6901 from Texas Instruments. The performance analysis of the device is done with respect …

Autonomous Robotic Automation Systemwith Vision Feedback, Jeffery Rosino

Electronic Theses and Dissertations

In this thesis, a full design, development and application of an autonomous robotic automation system using vision feedback is performed. To realize this system, a cylindrical manipulator configuration is implemented, using a personal computer (PC) based PID controller from National Instruments. Full autonomous control will be achieved via a programmable human machine interface (HMI) developed on a PC using Borland C++ Builder. The vision feedback position control is accomplished using an ordinary "off-the-shelf" web camera. The manuscript is organized as follows; After Chapter 1, an introduction to automation history and its role in the manufacturing industry, Chapter 2 discusses and …

Finite Element Analysis Of Left-Handed Waveguides, Balasubramaniam, Vellakkinar

Electronic Theses and Dissertations

In this work, waveguides with simultaneous negative dielectric permittivity and magnetic permeability, otherwise known as left-handed waveguides, are investigated. An approach of formulating and solving an eigenvalue problem with finite element method resulting in the dispersion relation of the waveguides is adopted in the analysis. Detailed methodology of one-dimensional scalar and two-dimensional vector finite element formulation for the analysis of grounded slab and arbitrary shaped waveguides is presented. Based on the analysis, for waveguides with conventional media, excellent agreement of results is observed between the finite element approach and the traditional approach. The method is then applied to analyze left-handed …