Engineering Commons^™

Minority-Carrier Mobility Enhancement In P+ Ingaas Lattice Matched To Inp, E. S. Harmon, Michael L. Lovejoy, Michael R. Melloch, Mark S. Lundstrom, D. Ritter, R. A. Hamm

Department of Electrical and Computer Engineering Faculty Publications

Minority electron mobilities in pf-In0.ssGac4, As have been measured with the zero field time-of-flight technique. The room-temperature (297 K) minority electron mobilities for p+-In,, 53Gac47A~ doped 0.9 and 3.1 x 10” cmm3 are found to be 2900 and 3300 cm* V-’ s-l, respectively. These are the first measurements to demonstrate enhancement in minority-carrier mobility as doping is increased for heavily doped Ines3Gae.4+s. This enhancement in mobility as doping is increased is similar to that observed in p+-GaAs, which has been attributed to reductions in plasmon and carrier-carrier scattering between minority electrons and majority holes.

Concentration‐Dependent Optical‐Absorption Coefficient In N‐Type Gaas, Gregory Benedict Lush, H. F. Macmillan, S. Asher, Michael R. Melloch, Mark S. Lundstrom

Department of Electrical and Computer Engineering Faculty Publications

The doping-dependent, near-band-edge optical-absorption coefficient CY(h v) was deduced from optical transmission measurements in n-type GaAs thin films. The selenium-doped films were grown by metalorganic chemical-vapor deposition and do ed to produce room-temperature electron concentrations from 1.3 x 10” to 3.8X 1018 cm- P . The transmission measurements covered photon energies between 1.35 and 1.7 eV and were performed on double heterostructures with the substrate removed by selective etching. The results show good qualitative agreement with previous studies and good quantitative agreement, except for the heavily doped samples. For na=3.8 X 10” cme3, a( 1.42 eV> is approximately four times …

Experimental Observation Of A Minority Electron Mobility Enhancement In Degenerately Doped P-Type Gaas, E. S. Harmon, Michael L. Lovejoy, Michael R. Melloch, Mark S. Lundstrom, T. J. De Lyon, J. M. Woodall

Department of Electrical and Computer Engineering Faculty Publications

The variation of minority electron mobility with doping density in p+-GaAs has been measured with the zero-field time-of-flight technique. The results from a series of nine GaAs films doped between 1 X lOI and 8 X 10” cmm3 show the mobility decreasing from 1950 cm2 V-’ s-l at 1 X 10” cmm3 to 1370 cm2 V-l s-l at 9X 10” cmB3. For the doping range 9 x 1018-8x 1019 cme3, the decreasing trend in mobility is reversed. The measured mobility of 3710 cm2 V-’ s-l at 8 X 10” cmp3 is about three times higher than the measured value at …

Feature Extraction And Classification Algorithms For High Dimensional Data, Chulhee Lee, David Landgrebe

Department of Electrical and Computer Engineering Technical Reports

In this research, feature extraction and classification algorithms for high dimensional data are investigated. Developments with regard to sensors for Earth observation are moving in the direction of providing much higher dimensional multispectral imagery than is now possible. In analyzing such high dimensional data, processing time becomes an important factor. With large increases in dimensionality and the number of classes, processing time will increase significantly. To address this problem, a multistage classification scheme is proposed which reduces the processing time substantially by eliminating unlikely classes from further consideration at each stage. Several truncation criteria are developed and the relationship between …

Chemical Admixtures Of Highway Concrete: Fundamental Research And A Guide To Usage, Sidney Diamond, Keisuke Matsukawa

JTRP Technical Reports

No abstract provided.

Introduction To Intellisim 2.0, Paul Savory

Department of Industrial and Management Systems Engineering: Faculty Publications

IntelliSIM is a prototype for a new generation of knowledge-based simulation tool that has been developed by the Systems Simulation Laboratory at Arizona State University. This tool is a computer environment that allows non-simulation trained modelers to predict the performance of a manufacturing system for which the necessary data is available. The system provides predictive data on such items as throughput time, queue levels, equipment utilization, reactions to machine failures, etc. With IntelliSIM, the benefits of discrete-event simulation can be exploited without requiring the high level of expertise necessary to successfully conduct a sound simulation study. The approach offered with …

Drying Rate Constants For Yellow Dent Corn As Affected By Fatty Acid Ester Treatments, Curtis L. Weller, J. M. Bunn

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Ethyl oleate and ethyl stearate solutions at various concentrations were used to treat corn samples prior to drying.

Modification Of Physical And Barrier Properties Of Edible Wheat Gluten-Based Films, Aristippos Gennadios, Curtis L. Weller, Robert F. Testin

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Edible films were produced from wheat gluten-based film-forming solutions. One film was produced as a control. Other types came from subjecting control films to three different soaking treatments. Three additional films were also produced by modifying the control film-forming solution. For all films, selected physical properties and permeability to water vapor and oxygen were measured. Comparisons indicated possible ways to improve the control film. All films were good oxygen barriers but limited water vapor barriers. Films containing hydrolyzed keratin had lower oxygen permeability (83%) and lower water vapor permeability (23%). Films containing mineral oil had lower water vapor permeability (25%). …

Surface Treatment For Mitigation Of Hydrogen Absorption And Penetration Into Aisi 4340 Steel, G. Zheng, Branko N. Popov, Ralph E. White

Faculty Publications

The effectiveness of underpotential deposition of Pb onto a membrane made of AISI 4340 steel on the reduction of the hydrogen evolution reaction on the membrane and the degree of hydrogen ingress into the membrane was determined. In the presence of a monolayer coverage of Pb on the membrane surface, the hydrogen evolution currents were reduced by a factor of two compared with the values obtained on bare steel, and the steady-state hydrogen permeation flux through the steel membranes was reduced by 71%.

Impedance Spectroscopy As A Nondestructive Health Interrogation Tool For Lithium-Bcx Cells, Branko N. Popov, W. Zhang, E. C. Darcy, Ralph E. White

Faculty Publications

The objective of this investigation was to study the growth of thick passivating layers on the Li anode in Li/BCX(Li/SOCl₂ + BrCl) cells which were stored for a period of 3 years. Impedance spectroscopy and equivalent circuit models were used to determine characterizing parameters for these cells. The equivalent circuit used for virgin cells includes a faradic contribution and diffusion of the electroactive species. The equivalent circuit for batteries stored 1 or 2 years includes the impedance of a metal/passive film interface, the resistance of the film, and the impedance of the passivating film/electrolyte interface. The equivalent circuit used …

Using Electrochemical Impedance Spectroscopy As A Tool For Organic Coating Solute Saturation Monitoring, Branko N. Popov, Mohammed A. Alwohaibi, Ralph E. White

Faculty Publications

Electrochemical impedance spectroscopy (EIS) has been used to study the solute uptake for epoxy/phenolic (E/p) andepoxy/amine (E/a) thick-coated mild steel samples immersed for 160 days in 3.5 weight percent NaCl solution exposed to air. Samples with thicknesses of approximately 200 µm with an exposed surface area of 22.6 cm² were used to follow solute saturation of the organic coating. Good agreement was obtained between the calculated and measured coating capacitance when, according to the diffusion equation, the coating capacitance was plotted against exposure time.

Galvanostatic Pulse And Pulse Reverse Plating Of Nickel-Iron Alloys From Electrolytes Containing Organic Compounds On A Rotating Disk Electrode, Branko N. Popov, Ken-Ming Yin, Ralph E. White

Faculty Publications

Linear sweep voltammetry, galvanostatic pulse, and pulse reverse techniques were used to study the plating of nickel-iron alloys in the presence of organic additives. The effects of pulse current densities, i_p, reverse current densities, i_r, rotation speed of disk electrode, and the presence of organic additives on deposition of nickel-iron alloys are evaluated. The observed phenomena can be explained by the concentration depletion of reactants (or products), and the surface coverage of the additives on the electrode. A new formulation of the plating bath is defined.

Impedance Analysis For Oxygen Reduction In A Lithium Carbonate Melt: Effects Of Partial Pressure Of Carbon Dioxide And Temperature, Bhasker B. Dave, Ralph E. White, Supramaniam Srinivasan, A. John Appleby

Faculty Publications

Effects of partial pressure of carbon dioxide and temperature on oxygen reduction kinetics on a gold electrode in a lithium carbonate melt were examined using electrochemical impedance spectroscopic (EIS) and linear sweep voltammetric techniques. The impedance spectra were analyzed by a complex nonlinear least squares method, using the Randles-Ershler equivalent circuit model, to determine the electrode-kinetic and the mass-transfer parameters such as the charge-transfer resistance and the Warburg coefficient. The cyclic voltammetric measurements indicated that the oxygen reduction process in lithium carbonate melt is "reversible" up to 200 mV/s. The product DC₀ determined by cyclic voltammetry agreed well …

Thermal Analysis Of Spirally Wound Li/Bcx And Li/Socl2 Cells, E. E. Kalu, Ralph E. White

Faculty Publications

A thermal analysis of Li/BCX and high rate Li/SOCl₂ cells is presented. The thermal model developed was used to study the effect of ambient temperature of discharge (0–40°C) on Li/BCX cells discharged at the same rate. The model predictions show that ambient temperature of discharge was critical in thermal management of the cell. For forced convection cooled cells, the model predicted that ambient temperature near room temperature (25°C) was required to achieve the lowest maximum temperature rise in the cell. Inclusion of the effects of reaction products to the model predictions showed that a constant composition assumption may be …

Chemical Tracing Techniques For Evaluating Rill Hydraulics, John E. Gilley, Eugene R. Kottwitz

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Development of water erοsiοn and surface water quality control practices requires information concerning the hydraulic characteristics of upland areas. The relatively small flow rates normally found within rills make measurement of hydraulic parameters difficult. Chemical tracing procedures, originally developed for stream and river systems, have been successfully used to measure rill flow properties. A chemical tracer of known concentration is added to the rill and by knowing the degree of dilutiοn at a downstream sampling point, flow rate can be calculated. Rill flow velocity can be measured by determining the time required for a slug of tracer material to travel …

Analytical Guidance Laws And Integrated Guidance/Autopilot For Homing Missiles, S. N. Balakrishnan, Donald T. Stansbery, J. H. Evers, J. R. Cloutier

Mechanical and Aerospace Engineering Faculty Research & Creative Works

An approach to integrated guidance/autopilot design is considered in this study. It consists of two parts: 1) recognizing the importance of polar coordinates to describe the end game in terms of problem description and measurement acquisition, the terminal guidance problem is formulated in terms of polar coordinates; 2a) through the use of the state transition matrix of the intercept dynamics, a closed form solution for the transverse command acceleration is obtained; and 2b) through a commonly used approximation on time-to-go and a coordinate transformation, a family of proportional navigation optimal guidance laws is obtained in a closed form. A typical …

Phosphorus Accumulation In Bottom Sediments Of Retention/Detention Ponds, Kriss Young Kaye

Retrospective Theses and Dissertations

Laboratory and field studies were conducted to characterize phosphorus in bottom sediments for retention/detention ponds. The laboratory studies, including batch and column experiments, were conducted to assess possible removal processes. Sediment core samples were collected from detention ponds receiving urban runoff. These cores were analyzed for phosphorus at different layers including accumulated top sediments and the lower parent soil beneath it at a depth of 1, 3, 5, 10 and greater than 10 cm. The phosphorus accumulation rate was found to decline with calculated overflow rates from an average storm. Also attenuation of phosphorus with sediment depth followed an exponential …

Simplified Jet-A Kinetic Mechanism For Combustor Application, Bahman Ghorashi, Chi-Ming Lee, Krishna Kundu

Scholarship Collection

Successful modeling of combustion and emissions in gas turbine engine combustors requires an adequate description of the reaction mechanism. For hydrocarbon oxidation, detailed mechanisms are only available for the simplest types of hydrocarbons such as methane, ethane, acetylene, and propane. These detailed mechanisms contain a large number of chemical species participating simultaneously in many elementary kinetic steps. Current computational fluid dynamic (CFD) models must include fuel vaporization, fuel-air mixing, chemical reactions, and complicated boundary geometries. To simulate these conditions a very sophisticated computer model is required, which requires large computer memory capacity and long run times. Therefore, gas turbine combustion …

Roller Compacted Concrete As A New Method For Building Dams And Its Economic Advantages, Sami Tannous

Electronic Theses & Dissertations

This document includes overviews of the planning and design processes, reviews of construction operations, evaluations of the behavior, and performance of completed dams. Included in this document are examples of roller-compacted concrete dam construction in the U.S., South America, Europe, Asia, and Australia. This document also provides information on the development of roller compacted concrete (RCC) to support the use of RCC in dam construction. This procedure offers rapid construction with a lower cost, compared with the traditional concrete practice, and challenges the economics of earthfill and rockfill embankment dams.

The Development Of A Solar Radiation Extinction Correction For Satellite Data, Widad I. Mohamed

Electronic Theses and Dissertations

The main objectives of this thesis are the following: 1) Remove the haze using water surfaces in Landsat satellite imagery of the visible and near-infrared regions for their properties of high absorption of solar radiation and weak reflection of it. The scattered solar radiation is most obvious in dark weakly reflecting regions such as water. The haze removal technique depends on subtraction of scattered light from picture elements within the satellite imagery. 2) Derive a formula and techniques for a given image to correct for extinction by transforming the observed intensity of the signal transmitted to the Landsat detector to …

Candi (Chemical And Irrigation Management) Users Manual, Vs 2.0., A. H. Aly, Richard C. Peralta

Civil and Environmental Engineering Faculty Publications

This manual describes an interactive computer model, CANOl. CANOl is a decision support tool designed to aid in on-farm pesticides and irrigation management. CANOl simulates downward chemical movement through the soil in response to different irrigation practices. CANOl estimates the relative amount of a non-polar organic chemical which remains in the soil profile by the time it reaches a specified depth. Future releases of CANOl will involve the management of different types of chemicals. CANOl is also able to delineate the wellhead protection areas for domestic wells. For this purpose, CANOl involves USEPA's model (MWCAP). Different versions of CANOl handle …

Best Management Of Pesticide And Irrigation Application Systems: Background And Candi Software, Alaa H. Aly, Richard C. Peralta, Howard M. Deer

Civil and Environmental Engineering Faculty Publications

In this chapter, we discuss a commonly-used volume balance approach for simulating the movement of water through the root zone. We then show how this approach can be coupled with pesticide leaching prediction. Finally we show how information about irrigation system design can be used with the previous processes. The result is an integrated approach for estimating the environmental consequences of irrigation and pesticide management.

Weapon System Integration For The Afit Virtual Cockpit, William E. Gerhard Jr.

Theses and Dissertations

The Air Force Institute of Technology is continuing research in the Virtual Cockpit. The Virtual Cockpit makes use of high performance graphics workstations, Virtual Environment technology, and Distributed Interactive Simulation network protocols to create a flight simulator based on the capabilities of the McDonnell Douglas F-15E Strike Eagle. The work presented in this thesis focuses on the design and implementation issues for integrating a weapons delivery capability. Weapons simulated include: RADAR and IR guided air- to-air missiles, gravity and precision guided bombs, and a 20mm cannon. Virtual Environment displays used include: color NTSC and monochrome high resolution helmet mounted displays …

A Model Of Electronic Warfare Systems Acquisition And Engineering For Saudi Arabia, Negaa M. Albegami

Doctoral Dissertations

"A major activity within the systems engineering process is the requirements definition and analysis phase. In technical systems, planning this phase looks too technical for top management and too broad for the engineers specialized in narrow technical fields. This categorization (too technical/too broad) represents a gap between top management and specialized engineering. In Saudi Arabia, such a gap is believed to be very wide.

The main objective of this research is to find a way to narrow this gap between management and engineering when planning government systems, especially in electronic warfare (EW) systems. A solution in this effort is to …

Galvanic Stripping Of Fe⁺³ And Pb⁺² Ions And Dissolution Of Metallic Fe, Zn, Pb And Cd Using Di(2-Ethylhexyl)Phosphoric Acid, Luis Miguel Chia Aquije

Doctoral Dissertations

"Two systems were evaluated using the principles of the galvanic stripping process. One of them, the removal of Pb⁺² ions from di-2(ethylhexyl) phosphoric acid (D2EHPA) was performed using metallic zinc. The other, the removal of Fe⁺³ ions from D2EHPA used metallic iron as reductant and was performed simultaneously with the organic phase using a slightly acidic aqueous solution of hydrochloric acid. In addition, the dissolution of metallic zinc, iron, lead, and cadmium in D2EHPA was studied in order to better understand the anodic step in the mechanism of the galvanic stripping process.

Increased temperature was found to dramatically …

Pump And Signal Cross Saturation In Cw Dye Lasers, Lee W. Casperson, A. C. Wilson, W. J. Sandle

Electrical and Computer Engineering Faculty Publications and Presentations

It is well known that the signal output intensity from a dye laser oscillator depends directly on the pump intensity. The opposite effect, the dependence of the transmitted pump intensity on the signal intensity, is studied in detail. The theoretical results are compared with experimental data obtained using an argon‐laser‐pumped rhodamine 6G dye laser.

Ultrashort‐Pulse Propagation In Dye Laser Amplifiers, Shuanghua Jiang, Lee W. Casperson

Electrical and Computer Engineering Faculty Publications and Presentations

A semiclassical model is presented for ultrashort‐pulse dye laser amplifiers. The model permits a discussion of important aspects of short‐pulse amplification such as pulse shape, pulse energy, and gain saturation. Coherence effects are found to be important in characterizing the evolution of amplified pulses in the subpicosecond and femtosecond regimes. The results are compared with those obtained using the corresponding rate equation model.

Hysteresis And Anchoring Energy In Ferroelectric Liquid Crystals, Yuri Panarin

Articles

The frequency dispersion of the coercive force of Ferroelectric Liquid Crystals (FLC) cells has been detected and examined in the range of infralow (lower than 0.1 Hz) frequencies. To clarify the low-frequency dispersion, the model has been suggested, based on the arrangement of free charges and well describing the experimental curves. The method for determination of the energy of FLC anchoring at the surface, developed on the basis of the static hysteresis loop, has been proposed. The dependence of bistability and the anchoring energy upon the orientant layer thickness has experimentally been investigated.

Design And Evaluation Of An Augmentative Communication Aid For Multiply Impaired Individuals, Mark S. Annett

Theses and Dissertations

Individuals with sensory and multiple physical impairments, which may include the loss of the ability to speak, have very specialized communication needs. Based on the belief that the current technology does not fully meet these needs, a prototype communication aid was developed for an individual who is cortically blind, dysphonic, and motor impaired. Furthermore, the communication device has broader applications beyond the present individual.

The prototype system has a direct selection of "Yes" and "No" responses, scanning access to daily phrases, rate enhancement of all scans, prompted encoding for selection of letters, two letter codes for complete sentences, access to …

Teaching A Smarter Learner, Sally A. Goldman, H. David Mathias

All Computer Science and Engineering Research

We introduce a formal model of teaching in which the teacher is tailored to a particular learner, yet the teaching protocol is designed so that no collusion is possible. Not surprisingly, such a model remedies the non-intuitive aspects of otehr models in which the teacher must successfully teach any consistent learner. We prove that any class that can be exactly identified by a deterministic polynomial-time algorithm with access to a very rich set of example-based queries is teachable by a computationally unbounded teacher and a polynomial-time learner. In addition, we present other general results relating this model of teaching to …