Digital Commons Network^™

Determination Of The Asymmetry Parameter And Scattering Coefficient Of Turbid Media From Spatially Resolved Reflectance Measurments, Matthew R. Jones, Yukio Yamada

Faculty Publications

We present a technique for determining the asymmetry parameter and scattering coefficient of turbid media from spatially resolved reflectance measurements. This technique will contribute to the development of medical applications in which it is necessary to predict the distribution and propagation of light in tissue. Based on Monte Carlo simulations, we derived correlations which relate the reduced scattering coefficient and the asymmetry parameter to the relative reflectance curve. Initial estimates of the optical properties are obtained from these correlations. Final values are obtained by adjusting the optical parameters and repeating the Monte Carlo simulations until the simulated reflectance pattern matches …

Diophantinized Fractional Representations For Nonlinear Elastomeric Media, Joe Padovan, Jerzy T. Sawicki

Mechanical Engineering Faculty Publications

This paper explores the use of diophantinized fractional fits for the nonlinear constitutive representation of elastomeric media. These are caste in terms of either the principal stretches or the strain invariants. Both polynomial and rational forms are considered. To construct the requisite complete and physically admissible basis space, the diophantinized set of fractional powers is bound by the curvature properties of the experimental data set. This set is then employed in conjunction with a remezed least square scheme to obtain an optimal fit. To verify the scheme a sample application case is presented.

Studies Of Metallic Multilayer Structures, Optical Properties, And Oxidation Using In Situ Spectroscopic Ellipsometry, Xiang Gao, Jeff Hale, Scott Heckens, John A. Woollam

Department of Electrical and Computer Engineering: Faculty Publications

In situ spectroscopic ellipsometry (SE) has been successfully used to accurately measure sputter deposition rates and optical constants of un-oxidized metal layers and to control the growth of magnetic multilayers. The structures include [Co/Cu] _n , [Co/Au] _n , [Co/Ni] _n , [Co/Pd] _n and [Co/Pd/ Au] _n . Layer thickness precision is better than ±0.05 nm for layer thicknesses in the range of 0.2 nm to 10 nm. Closed-loop feedback control of layer thickness is also demonstrated. Good consistency was obtained by comparing the in situ SE results to x-ray diffraction measurements. Dynamic oxidation studies of [Co/Au] _n and …

Design, Performance, And Applications Of A Coherent Ultra-Wideband Random Noise Radar, Ram M. Narayanan, Yi Xu, Paul D. Hoffmeyer, John O. Curtis

Department of Electrical and Computer Engineering: Faculty Publications

A novel coherent ultra-wideband radar system operating in the 1- to 2-GHz frequency range has been developed recently at the University of Nebraska. The radar system transmits white Gaussian noise. Detection and localization of buried objects is accomplished by correlating the reflected waveform with a time-delayed replica of the transmitted waveform. Broadband dual-polarized log-periodic antennas are used for transmission and reception. A unique signal-processing scheme is used to inject coherence into the system by frequency translation of the ultrawideband signal by a coherent 160-MHz phase-locked source prior to performing heterodyne correlation. The system coherence allows the extraction of a target’s …

Worst-Case Error Probability Of A Spread-Spectrum System In Energy-Limited Interference, Murad Hizlan, Brian L. Hughes

Electrical and Computer Engineering Faculty Publications

We consider a communication channel corrupted by thermal noise and by an unknown and arbitrary interference of bounded energy. For this channel, we derive a simple upper bound to the worst-case error probability suffered by a direct sequence (DS) communication system with error-correction coding, pseudorandom interleaving, and a correlation receiver. This bound is exponentially tight as the block length of the error correcting code becomes large. Numerical examples are given that illustrate the dependence of the bound on the choice of error correcting code, the type of interleaving used, and the relative energy of the Gaussian noise and arbitrary interference

Orthogonal Transmultiplexers : Extensions To Digital Subscriber Line (Dsl) Communications, Xueming Lin

Dissertations

An orthogonal transmultiplexer which unifies multirate filter bank theory and communications theory is investigated in this dissertation. Various extensions of the orthogonal transmultiplexer techniques have been made for digital subscriber line communication applications.

It is shown that the theoretical performance bounds of single carrier modulation based transceivers and multicarrier modulation based transceivers are the same under the same operational conditions. Single carrier based transceiver systems such as Quadrature Amplitude Modulation (QAM) and Carrierless Amplitude and Phase (CAP) modulation scheme, multicarrier based transceiver systems such as Orthogonal Frequency Division Multiplexing (OFDM) or Discrete Multi Tone (DMT) and Discrete Subband (Wavelet) Multicarrier …

Design, Fabrication And Characterization Of The Infrastructure For A Two Part Non Volatile Ram, Suma Madapur

Theses

The present trend is to be able to develop cheaper and more convenient methods to design and fabricate non volatile RAM that will lead to an alteration of the computer architecture itself This will help replace the DRAM, which the computers currently have in their memory. The proposed NVRAM is designed to overcome the common difficulties faced with the use of ferroelectric materials used in the fabrication of NVRAM. The new idea essentially consists of fabricating the circuitry component separately and the substrate component separately and binding the two with the help of a conducting material. Electrical properties such as …

Introduction To Pollution Prevention Concepts In Freshman Chemistry Through Simulations And Hypermidia, Aniraban Bhaumik

Theses

As citizens of the 20th century, a key issue we all are aware of is degradation of the environment. In the interest of teaching the environmental issues to freshmen engineers, this study develops a computer aided learning/teaching (CAL/T) tool.

This CAL/T tool consists of Internet based multimedia courseware and intelligent simulations. The courseware assembles the fundamentals of chemistry associated with current environmental issues such as air pollution, stratospheric ozone layer depletion and environmentally sensitive or 'clean' manufacturing. The courseware targets early and comprehensive understanding of pollution prevention concepts with a focus on environmentally friendly manufacturing. The courseware includes: on-line text, …

The In0.75ga0.25as/In0.52al0.48as/Inp Hall Effect Magnetic Field Sensor, Oleg Mitrofanov

Theses

The magnetic field sensor is produced from III-V group semiconductor materials. The structure is designed for molecular beam epitaxy growth technique (MBE) on the semiinsulating InP substrate. The sensitive element is the In_0.75Ga_0.25As/In_0.52Al_0.48As heterostructure. The sensor uses the classic Hall effect in two-dimension electron gas (2DEG) formed at pseudomorphic strained epilayer of In_0.75Ga_0.25As. Properties of the 2DEG are preferential for the Hall effect sensor performance. Comparatively to bulk, electron mobility is higher. The device combines high magnetic field sensitivity and temperature stability. The sensor is designed for operation …

Acuta Enews January 1998, Vol.27, No. 1

ACUTA Newsletters

In This Issue

School NOT Required to Contribute to USF

What's Your Biggest Challenge for 1998?

Board Report

Spotlight

Analyzing Cable Needs and Planning for the Future at CMU

Tech Partners at Cal State

Directories Are Here!

DC at a Glance

Position Available

Welcome New Members

Birkman Screening And The Covariance Of The Fluid Velocity Of Fixed Beds, Ashok S. Sangani, Donald L. Koch, Reghan J. Hill

Biomedical and Chemical Engineering - All Scholarship

The phenomenon of Brinkman screening, whereby the fluid velocity disturbance produced by each particle in a fixed bed is attenuated by the forces that the fluid exerts on surrounding particles, plays a crucial role in limiting the range of velocity correlations in porous media and fixed beds. Koch and Brady [J. Fluid Mech. 154, 399 (1985)] showed theoretically that Brinkman screening leads to a finite hydrodynamic diffusion coefficient for fluid phase tracers in dilute fixed beds. In this Letter, we present the results of two simulation techniques (lattice-Boltzmann method and a multipole method) confirming the screening of the fluid velocity …

Tissue Engineering: At The Interface Between Engineering, Biology And Medicine, Brenda Ogle, Priti Gairola, Jodi Balik, Daniel L. Mooradian

Journal of the Minnesota Academy of Science

No abstract provided.

Personal Reflections On Psi In Engineering Mechanics, David Haws

Civil Engineering Faculty Publications and Presentations

There seems to be little argument that our students need to be encouraged toward educational selfdirectedness. Yet self-direction must be based on past learning success and present learning readiness. There is at least a potential conflict here: students needs to assume responsibility for their own education, directing it to topics of their own choosing, but their learning must also at least occasionally be directed along a hierarchical path of sequentially dependent learning objectives (which path may not be so obvious to the uninitiated). The Personalized System of Instruction (PSI) seems to enable both of these not-always-compatible goals. PSI allows the …

Fall 1998, 90.9 Wmpg Fm

WMPG Program Guides

No abstract provided.

Compilation Techniques For Out-Of-Core Parallel Computations, Mahmut Kandemir, Alok Choudhary, J. Ramanujam, Rajesh Bordawekar

Electrical Engineering and Computer Science - All Scholarship

The difficulty of handling out-of-core data limits the performance of supercomputers as well as the potential of the parallel machines. Since writing an efficient out-of-core version of a program is a difficult task and virtual memory systems do not perform well on scientific computations, we believe that there is a clear need for compiler directed explicit I/O approach for out-of-core computations. In this paper, we first present an out-of-core compilation strategy based on a disk storage abstraction. Then we offer a compiler algorithm to optimize locality of disk accesses in out-of core codes by choosing a good combination of file …

A Web-Based Universal Encyclopedia/Dictionary, Francis Hyeongwoo Lee

Theses Digitization Project

No abstract provided.

Santa Clara Magazine, Volume 39 Number 4, Winter 1998, Santa Clara University

Santa Clara Magazine

10 - INSIDE OUT Francisco Jimenez, chairman of the University's Modern Languages and Literatures Department, recalls his grade-school days and immigrant family.

14 - FROM HALLOWED TO HIP Connie Hinckley, East Bay writer, examines the media's many-faceted portrayals of the priesthood, especially the controversial Father Ray of Nothing Sacred.

20 - SANTA CLARA'S ADOBE LEGACY Susan Vogel, San Francisco author and publisher, traces the history of the Adobe Lodge and describes its many roles in the life of the University.

26 - UNCOVERING THE REGION'S RICH PAST As the University clears land for new buildings, SCU archeologists and Native American …

On Block-Coded Modulation Using Unequal Error Protection Codes Over Rayleigh-Fading Channels, Robert H. Morelos-Zaragoza, Tadao Kasami, Shu Lin, Hideki Imai

Faculty Publications

This paper considers block-coded 8-phase-shift-keying (PSK) modulations for the unequal error protection (UEP) of information transmitted over Rayleigh-fading channels. Both conventional linear block codes and linear UEP (LUEP) codes are combined with a naturally labeled 8-PSK signal set, using the multilevel construction of Imai and Hirakawa (1977). Computer simulation results are presented showing that, over Rayleigh-fading channels, it is possible to improve the coding gain for the most significant bits with the use of binary LUEP codes as constituent codes, in comparison with using conventional binary linear codes alone.

Biogenic Iron Mineralization Accompanying The Dissimilatory Reduction Of Hydrous Ferric Oxide By A Groundwater Bacterium, James K. Fredrickson, John M. Zachara, David Kennedy, Hailang Dong, Tullis Onstott, Nancy Hinman, Shu-Mei Li

United States Department of Energy: Publications

Dissimilatory iron-reducing bacteria (DIRB) couple the oxidation of organic matter or H2 to the reduction of iron oxides. The factors controlling the rate and extent of these reduction reactions and the resulting solid phases are complex and poorly understood. Batch experiments were conducted with amorphous hydrous ferric oxide (HFO) and the DIRB Shewanella putrefaciens, strain CN32, in well-defined aqueous solutions to investigate the reduction of HFO and formation of biogenic Fe(II) minerals. Lactate-HFO solutions buffered with either bicarbonate or 1,4-piperazinediethanesulfonic acid (PIPES) containing various combinations of phosphate and anthraquinone-2,6-disulfonate (AQDS), were inoculated with S. putrefaciens CN32. AQDS, a humic …

Apparatus And Method For Detection And Concentration Measurement Of Trace Metals Using Laser Induced Breakdown Spectroscopy, Dennis R. Alexander

Department of Electrical and Computer Engineering: Faculty Publications

A method and apparatus for in situ detection and concentration measurement of trace elements in an analysis Sample is disclosed. The invention uses laser induced breakdown spectroscopy (LIBS) wherein femtosecond pulsed laser energy is employed to produce the plasma. The femtosecond pulsed laser energy is focused on the analysis Sample to produce the plasma and the resulting emission is delivered for spectral analysis. Because the method and apparatus of the present invention allow breakdown of the analysis Sample without propagation of energy to the Sample-air interface, a plasma is produced that consists essentially of Sample materials without being contaminated by …

Networking 8-Bit Embedded Controllers, Using The Controller Area Network Method, Brett Wilkinson

Theses : Honours

The initial aim of this project was to create an ethernet (IEEE 802.3) Communications System. The system was to connect Embedded controllers to facilitate the operation of a real time operation. After extensive investigation and scheduled meetings with industry, it became apparent that a superior communication system for this type of task lay in the Controller Area Network (CAN) standard. Communications Networks are extremely susceptible to volatile surroundings. A vital controller network necessitates that its communication network be invulnerable to high noise levels. It is also imperative that critical messages from one controller reach their destination on time. CAN was …

Validating A Vegetative Filter Strip Performance Model, Puneet Srivastava, Thomas A. Costello, Dwayne R. Edwards, James A. Ferguson

Biosystems and Agricultural Engineering Faculty Publications

Vegetative filter strips (VFS) reduce losses of nutrients, solids, and other materials from land area treated with fertilizers and manures. A number of models are available that simulate nutrient and sediment transport in VFS. While VFS effectiveness is considered to depend on lengths of pollutant source area and VFS areas, few published studies have tried to validate these models using variable pollutant source area and VFS area. The objective of this study was to validate an event-based nutrient transport model (Chaubey et al., 1995) that simulates soluble nutrient transport in VFS. This model links three sub-models: modified Green-Ampt infiltration, non-linear …

Dynamic Analysis Of Unidirectional Pressure Infiltration Of Porous Preforms By Pure Metals, Dhiman K. Biswas, Jorge E. Gatica, Surendra N. Tewari

Chemical & Biomedical Engineering Faculty Publications

Unidirectional pressure infiltration of porous preforms by molten metals is investigated numerically. A phenomenological model to describe fluid flow and transport phenomena during infiltration of fibrous preforms by a metal is formulated. The model describes the dynamics of the infiltration process, the temperature distribution, and solid fraction distribution. The numerical results are compared against classical asymptotic analyses and experimental results. This comparison shows that end effects may become important and render asymptotic results unreliable for realistic samples. Fiber volume fraction and initial temperature appear as the factors most strongly influencing infiltration. Metal superheating affects not only the length of the …

Tcp/Ip Implementation With Endsystem Qos, Sherlia Y. Shi, Gurudatta M. Parulkar, R. Gopalakrishnan

All Computer Science and Engineering Research

This paper presents a Real-time Upcall (RTU) [1] based TCP/IP implementation that guarantees throughput for continuous media applications and ensures low latency bounds for interactive applications. RTU is an endsystem rate-based scheduling mechanism that provides quality of service (QoS) in terms of CPU cycles, to applications. We restructured the existing NetBSD TCP/IP implementation to exploit the RTU concurrency model and to provide predictable performance. Our experimental results show that on two 200 MHz NetBSD PCs connected by a 155Mbps ATM link, the RTU based kernel TCP/IP implementation provides excellent throughput guarantees for periodic connections regardless the system or network load. …

Virtual Reality Modelling Of A Cnc Machine, Damian O'Sullivan

Theses

The increasing importance of training and upgrading skills has led to the use of new interactive technologies in the development of more effective training tools. Previous techniques for training Computer Numerical Control (CNC) machine operators, while excellent for their time, varied from brief inexpensive tutorials to expensive on the job training. A CNC machine uses a computer to perform the functions of the machine using a part program stored in the memory of the computer. This thesis describes a Virtual Reality (VR) model of a CNC milling machine, implemented within a VR environment representing a CNC workshop. Its development and …

A Study Of The Fundamental Operations Of A Capillary Driven Heat Transfer Device In Both Normal And Low Gravity Part 1-Liquid Slug Formation In Low Gravity, Jeffrey S. Allen, Kevin P. Hallinan, Jack Lekan

Mechanical and Aerospace Engineering Faculty Publications

Research has been conducted to observe the operation of a capillary pumped loop (CPL) in both normal and low gravity environments in order to ascertain the causes of device failure. The failures of capillary pumped heat transport devices in low gravity; specifically; evaporator dryout, are not understood and the available data for analyzing the failures is incomplete.

To observe failure in these devices an idealized experimental CPL was configured for testing in both a normal-gravity and a low-gravity environment. The experimental test loop was constructed completely of Pyrex tubing to allow for visualization of system operations. Heat was added to …

Fdtd Evaluation Of The Sar Distribution In A Human Head Near A Mobile Cellular Phone, Selçuk Paker, Levent Sevgi̇

Turkish Journal of Electrical Engineering and Computer Sciences

In this study, Finite-Difference Time-Domain (FDTD) method is used to calculate the Specific Absorbtion Rate (SAR; defined as the power absorbed by unit mass of the tissue) distribution in a human head near a hand-held cellular phone. A three dimensional FDTD algorithm is built in cartesian coordinates. A discrete human head model, derived from a Nuclear Magnetic Resonance (NMR) image by semi-automatic algorithm, is located within FDTD volume together with a discrete hand-held receiver model. FDTD simulations are carried out for both european GSM (operating at 900MHz) and DECT (operating at 1.8GHz) systems with a quarter-wavelength antenna, mounted on top …

Influence Of Iron Oxide Inclusion Shape On Coii/Iiiedta Reactive Transport Through Spatially Heterogeneous Sediment, James E. Szecsody, Ashley Chilakapati, John M. Zachara, Amanda Garvin

United States Department of Energy: Publications

Multisolute reactive transport was investigated in chemically heterogeneous systems to determine the influence of the shapes of the reactive heterogeneities (iron oxide inclusions) by comparison of two-dimensional heterogeneous experiments with spatially averaged models that had differing inclusion characterization. Eleven reactions were considered in this system, starting with absorption of the initial solute (Co^IIEDTA) to Fe oxides, followed by two competing surface reactions: oxidation forming Co^IIIEDTA and Fe dissolution forming Fe^IIIEDTA and Co2+. Spatial moments of the eight mobile species were compared between data and models. One spatially averaged model (homogenous equivalent), which incorporated inclusion …

Bacterial Reduction Of Crystalline Fe3+ Oxides In Single Phase Suspensions And Subsurface Materials, John M. Zachara, James K. Fredrickson, Shu-Mei Li, David W. Kennedy, Steven C. Smith, Paul L. Gassman

United States Department of Energy: Publications

Microbiologic reduction of synthetic and geologic Fe³⁺ oxides associated with four Pleistocene- age, Atlantic coastal plain sediments was investigated using a dissimilatory Fe reducing bacterium (Shewanella putrefaciens, strain CN32) in bicarbonate buffer. Experiments investigated whether phosphate and anthraquinone-2, 6-disulfonate, (AQDS, a humic acid analogue) influenced the extent of crystalline Fe³⁺ oxide bioreduction and whether crystalline Fe³⁺ oxides in geologic materials are more or less reducible than comparable synthetic phases. Anaerobic incubations (10⁸ organisms/mL) were performed both with and without PO₄ and AQDS that functions as an electron repository and shuttle. The production of …

Master Of Science Degree Programs 1998, Nova Southeastern University

College of Engineering and Computing Course Catalogs

No abstract provided.