Engineering Commons^™

Turbomachine Stability And Forced Response Prediction, Leland Bert Clark

Open Access Theses

A mathematical model is developed and utilized to analyze turbomachine cascade flutter and forced response. The flutter boundary, defined as the largest value of reduced frequency at which flutter occurs for a given cascade, was evaluated for single degree of freedom torsional oscillation as well as coupled bending and torsional oscillations. The maximum amplitude of forced response in bending and torsion was also considered. The unsteady aerodynamic lift and moment coefficients were determined from unsteady aerodynamic flow models for subsonic flow, supersonic flow with a subsonic axial component and supersonic axial flow. The effect of changing the Mach number, stagger …

Losses In Electric Power Systems, E. Benedict, T. Collins, D. Gotham, S. Hoffman, D. Karipides, S. Pekarek, R. Ramabhadran

Department of Electrical and Computer Engineering Technical Reports

This report concerns losses in power systems. The report was assembled by seven authors in EE 532 class at Purdue University in December, 1992. The work was part of a class project on losses . All aspects of losses are discussed from the transmission system through utilization stages. High efficiency motors and lighting are also considered . The students participating in this project also videotaped presentations on power system losses .

Guide To Revenue Calculations: Local Option Highway User Tax 1992, Jon D. Fricker

Indiana Local Technical Assistance Program (LTAP) Publications

This guide is provided to explain the output generated by the computer programs, and to suggest ways in which the results can be adapted to specific LOHUT proposals before a County Council. HERPICC neither endorses nor opposes passage of a LOHUT. The revenue projections it provides are intended to be an aid to well-informed decision-making on the part of a county’s citizens and its County Council.

Oxidative Mechanisms In Arterial Distension Injury: Observations Relevant To Restenosis After Angioplasty, Charles F. Babbs, Yuan Zhong

Weldon School of Biomedical Engineering Faculty Working Papers

Background: To explore the hypothesis that tissue iron and reactive oxygen species, including superoxide (O2), mediate acute inflammatory and late hyperplastic responses to vascular injury, we studied experimental overdistension of normal carotid and femoral arteries in dogs. Experimental design: Arterial segments isolated in situ were distended with Ringer solution at 2 atmospheres pressure. In initial experiments the arteries were excised immediately after distension and immersed in diaminobenzidine solutions containing Mn++ ions to initiate histochemical reactions for O2. In other experiments distended arterial segments were reperfused with arterial blood in the presence or absence of the iron chelator, deferoxamine, or the …

Implementation Of Back-Propagation Neural Networks With Matlab, Jamshid Nazari, Okan K. Ersoy

Department of Electrical and Computer Engineering Technical Reports

The artificial neural network back propagation algorithm is implemented in Matlab language. This implementation is compared with several other software packages. The effect of reducing the number of iterations in the performance of the algorithm iai studied. The speed of the back propagation program, mkckpmp, written in Matlab language is compared with the speed of several other back propagation programs which are written in the C language. The speed of the Matlab program mbackpmp is, also compared with the C program quickpmp which is a variant of the back propagation algorithm. It is shown that the Matlab program mbackpmp is …

Evidence That Free Fatty Acid-Iron Complexes Directly Initiate Lipid Peroxidation In Vitro And In Vivo: A New Mechanism Of Oxidative Stress, Steven C. Salaris, Charles F. Babbs, Joann Pham, John J. Turek

Weldon School of Biomedical Engineering Faculty Working Papers

Through a series of biochemical and histochemical experiments we explored the novel hypothesis that iron and free fatty acids, liberated after tissue injury, combine to form liposoluble complexes that directly initiate lipid peroxidation. The addition of 100 M ferric iron to 30 mM linoleate suspensions at pH 7.4 produced time dependent lipid peroxidation, measured as conjugated diene formation. Complexes of 100 M ferric iron and 600 M pentanoate also initiated formation of conjugated dienes in linoleate suspensions and formation of malondialdehyde-like materials in rat liver slices. A histochemical stain for free fatty acids revealed positive reactions within cell membranes in …

A Study Of Numerical Integration Techniques For Use In The Companion Circult Method Of Transient Circuit Analysis, Charles A. Thompson

Department of Electrical and Computer Engineering Technical Reports

Circuit transient analysis packages such as SPICE and EMTP are very widely used, but detailed information on the internal structure and error characteristics for these software packages is lacking. Both SPICE and EMTP rely on numerical integration to approximate the transient response of circuit elements. The numerical integration methods used in the packages are not necessarily the most accurate approximations to the actual response of a circuit. The study of these numerical integration methods and their error characteristics is the focus of this thesis. Comparisons are made between several methods in terms of accuracy and stability as well as algorithm …

Three-Dimensional Insulated Gate Bipolar Transistor (Igbt) Development, P.V. Gilbert, G.W. Neudeck

Department of Electrical and Computer Engineering Technical Reports

A new insulated gate bipolar transistor structure, the 3D-IGBT, is presented. The 3D-IGBT utilizes selective epitaxial silicon to form a top contacted anode and still retain the cellular structure of vemcally oriented devices. The 3D-IGBT , unlike other fully integrable power devices, exploits the merits of cellular structure to increase its packing density and thus reduce its on-resistance per unit area. It also eliminates the parasitic JFET resistance found in vertical IGBT's. To integrate the 3D-IGBT with low power devices, the QDI method of device isolation is also presented. QDI uses a combination of JI and DI to electrically isolate …

Manual Of Traffic Impact Studies : Draft, Soumya Sekhar Dey, Jon D. Fricker

JTRP Technical Reports

With intensification urban development and dwindling public resources, assessing the impacts of a new development (traffic impact analysis) is becoming an important planning tool for transportation engineers, so that the traffic impacts of new developments can be foreseen and effective mitigating measures can be planned using optimal allocation of the available funds. The study establishes a detailed and standardized methodology for traffic impact analysis. Although the procedure was developed for the Indiana Department of Transportation, it can be used by other transportation agencies as well with little or no modification.

A new methodology for estimating the percentage of pass-by trips …

Minority Hole Mobility In N+ Gaas, Michael L. Lovejoy, Michael R. Melloch, Mark S. Lundstrom, R. K. Ahrenkiel

Department of Electrical and Computer Engineering Faculty Publications

The minority hole diffusivity, or equivalently the hole mobility, was measured in n⁺GaAs with the zero‐field time‐of‐flight technique. The minority hole mobility was measured for the donor doping range of 1.3×10¹⁷ cm⁻³ to 1.8×1018 cm⁻³ and was found to vary from 235 to 295 cm²/V s. At the lower doping level, the minority hole mobility is comparable to the corresponding majority hole mobility, but at 1.8×10¹⁸ cm⁻³ the minority hole mobility was 30% higher than the majority carrier hole mobility. These results have important implications for the design of devices such …

Self‐Consistent Scattering Matrix Calculation Of The Distribution Function In Semiconductor Devices, Mark A. Stettler, Mark S. Lundstrom

Department of Electrical and Computer Engineering Faculty Publications

The scattering matrix approach is a new technique for solving the Boltzmann equation in devices. We report a self-consistent application of the technique to realistic silicon devices exhibiting strong nonlocal effects. Simulation of a hot-electron, n-i-n diode demonstrates that the new technique efficiently and accurately reproduces Monte Carlo results without the statistical noise, allowing much tighter convergence with Poisson’s equation.

Microsecond Lifetimes And Low Interface Recombination Velocities In Moderately Doped N-Gaas Thin Films, Gregory Benedict Lush, D. H. Levi, H. F. Macmillan, Michael R. Melloch, Mark S. Lundstrom, R. K. Ahrenkiel

Department of Electrical and Computer Engineering Faculty Publications

We have observed lifetimes greater than 1 ps in moderately doped, thin film, n-GaAs/A1a,Gae,As double heterostructure membranes formed by etching away the substrate. We attribute these ultralong lifetimes to enhanced photon recycling caused by the removal of the substrate. Nonradiative recombination in the bulk and at the interfaces is very low; the upper limit of the interface recombination velocity is 25 cm/S.-Such long lifetimes in GaAs doped at N,= 1.3 X 10” cme3 suggest that thin-film solar cells offer a potential option for achieving very high efficiencies.

Comparative Study Of Minority Electron Properties In P+-Gaas Doped With Beryllium And Carbon, Michael L. Lovejoy, Michael R. Melloch, Mark S. Lundstrom, R. K. Ahrenkiel, B. M. Keyes, T. J. De Lyon, J. M. Woodall

Department of Electrical and Computer Engineering Faculty Publications

Minority electron properties in p+‐GaAs doped with beryllium (Be) and with carbon (C) are reported. Measurements of essentially identical responses for structures differing only in dopant element demonstrate that the diffusivity (Dn) and the diffusion lengths (Ln) are the same in p+‐GaAs doped to ∼1019 cm−3 with Be‐ and C‐dopants. Zero‐field time‐of‐flight analysis yields Dn=35 cm2/s and internal quantum efficiency analysis yields Ln=2.4 μm, which implies a lifetime that is approximately at the estimated radiative limit. In addition, the majority Hall mobility was also found to be identical …

A Study Of Minority Carrier Lifetime Versus Doping Concentration In N‐Type Gaas Grown By Metalorganic Chemical Vapor Deposition, Gregory Benedict Lush, H. F. Macmillan, B. M. Keyes, D. H. Levi, Michael R. Melloch, R. K. Ahrenkiel, Mark S. Lundstrom

Department of Electrical and Computer Engineering Faculty Publications

Time‐resolved photoluminescence decay measurements are used to explore minority carrier recombination in n‐type GaAs grown by metalorganic chemical vapor deposition, and doped with selenium to produce electron concentrations from 1.3×10¹⁷ cm⁻³ to 3.8×10¹⁸ cm⁻³. For electron densities n₀<10¹⁸ cm⁻³, the lifetime is found to be controlled by radiative recombination and photon recycling with no evidence of Shockley–Read–Hall recombination. For higher electron densities, samples show evidence of Shockley–Read–Hall recombination as reflected in the intensity dependence of the photoluminescence decay. Still, we find that radiative recombination and photon recycling are important for …

Minority Electron Transport In Inp/Ingaas Heterojunction Bipolar Transistors, Paul Dodd, Mark S. Lundstrom

Department of Electrical and Computer Engineering Faculty Publications

Electron transport across the base of InP/InGaAs heterojunction bipolar transistors is examined by Monte Carlo simulation. The base transit times and electron distribution functions are examined as a function of basewidth. Clear ballistic behavior is observed only for extremely thin bases (much less than 100 A). Over the range of basewidths of interest for devices, base transport appears diffusive, but the electrons are very far from thermal equilibrium. The diffusive behavior is shown to arise from the sensitivity of the steady-state carrier population to small amounts of large-angle scattering.

A Computer-Based, Automated, Telephonic System To Monitor Patient Progress In The Home Setting, Umesh H. Patel, Charles F. Babbs

Weldon School of Biomedical Engineering Faculty Publications

In this report we describe an automated, telephonic system to monitor the progress of patients convalescing at home. The system includes a computerized central station that is capable of automated voice communication over the telephone, using voice reproduction, and touch-tone recognition. Peripheral hardware in multiple monitored homes need include only a touch-tone telephone, but may also be augmented by inexpensive, rudimentary diagnostic aids, such as a scale for body weight, a thermometer, or a blood pressure cuff and manometer. Current central hardware includes a NeXT computer, a fax modem, and a specialized telecommunications modem developed specifically for voice telecommunication using …

Oxygen Radicals In Ulcerative Colitis, Charles F. Babbs

Weldon School of Biomedical Engineering Faculty Publications

This article reviews the pathophysiologic concept that superoxide and hydrogen peroxide, generated by activated leukocytes, together with low-molecular-weight chelate iron derived from fecal sources and from denatured hemoglobin, amplify the inflammatory response and subsequent mucosal damage in patients with active episodes of ulcerative colitis. The putative pathogenic mechanisms reviewed are as follows: ( l ) Dietary iron is concentrated in fecal material owing to normally limited iron absorption. (2) Mucosal bleeding, characteristic of ulcerative colitis, as well as supplemental oral iron therapy for chronic anemia, further conspire to maintain or elevate mucosal iron concentration in colitis. (3) Fenton chemistry, driven …

Histochemical Demonstration Of Endothelial Superoxide And Hydrogen Peroxide Generation In Ischemic And Reoxygenated Rat Tissues, Charles F. Babbs, Meloney D. Cregor, Stephen F. Badylak

Weldon School of Biomedical Engineering Faculty Publications

Objective: The aims were to test and evaluate two novel and independent histochemical methods for detecting the initial postischemic burst of superoxide and hydrogen peroxide in buffer perfused rat tissues during reflow after 60 min warm ischemia. Methods: The first is a high manganese/diaminobenzidine technique, in which superoxide oxidises Mn2+ to Mn3+, which in turn oxidizes diaminobenzidine to form amber colored polymers, observable by light microscopy. The second is a high iron/diaminobenzidine technique, in which hydrogen peroxide oxidizes diethylenetriaminepenta-acetate chelated Fe2+ to form intermediate species, which in turn oxidize diaminobenzidine similarly to Mn3+. Various isolated organs of the rat were …

Evidence Of Changes In Regional Blood Perfusion In Human Intracranial Tumours During Conductive Interstitial Hyperthermia, U H. Patel, Charles F. Babbs, J A. Deford, W M. Bleyer, J A. Marchosky, C J. Moran

Weldon School of Biomedical Engineering Faculty Publications

Human intracranial tumours were treated using local heat therapy produced by surgically implanted catheters containing local resistive heating elements. Changes in local tumor blood flow were assessed indirectly from an algorithm based on the bioheat transfer equation. The algorithm used the ratio of catheter power to catheter temperature rise to estimate regional blood perfusion. Local heat therapy produced consistent reductions in local apparent perfusion. Changes in apparent regional perfusion occurred in intriguing patterns that gave clues to possible vascular events of therapeutic significance.

1992 Directory Of Indiana State, County, City And Town Officials Responsible For Road And Street Work, Herpicc

Indiana Local Technical Assistance Program (LTAP) Directory

Contact information for agency officials and employees responsible for Indiana’s local road infrastructure.

Potential Use Of Tire Rubber And Ebonite In Asphalt: Synthesis Study : Executive Summary, Abidin Kaya

JTRP Technical Reports

No abstract provided.

Development Of Quality Assurance Specifications For Bridge Painting Contracts, Luh M. Chang, Machine Hsie, David Unkefer

JTRP Technical Reports

No abstract provided.

Implementation Of The Indiana Bridge Management System, User's Manual, Lisa Chow Gion, Justin Gough, Jeffrey Dunn Vitale, Kumares C. Sinha, Robert E. Woods

JTRP Technical Reports

This report provides a user's manual for the implementation of the project evaluation and program development part of the Indiana Bridge Management System (IBMS). The tools and techniques found in these programs were primarily developed from previous research by the Joint Highway Research Project at purdue University. The IBMS runs on an IBM-compatible computer under 05/2.

The Use Of Advanced Technologies In Indiana Department Of Transportation, Thomas R. Kruse, Kumares C. Sinha, Ted M. Andrews, Jon D. Fricker, James Samuel Bethel, Michael J. Cassidy, Jorge A. Vanegas

JTRP Technical Reports

The report presents the findings of a study that investigated the potential uses of new technologies in INDOT. A survey of state transport agencies were conducted and the major groups of technologies identified are: CADD, GIS, Advanced Survey Techniques, Knowledge-Based Expert Systems, Planning and Programming Mdels, and a workshop with the INDOT executive staff were conducted to determine the priority areas for advanced technology applications. Suggestions were then made for the development of a new technology program within INDOT.

Fatigue Strength And Evaluation Of Sign Structures, Volume 1: Analysis And Evaluation, Xuejun Li, Timothy M. Whalen, Mark D. Bowman

JTRP Technical Reports

This report is a two-volume final report presenting the findings of the research work that was undertaken to evaluate the fatigue behavior of sign structures and, based on that evaluation, to recommend an inspection plan that can be effectively used to detect and minimize possible deterioration due to wind induced loadings of sign structures. The study included a number of signs that are commonly used in Indiana: single-mastarm and double-mastarm cantilever sign structures, box-truss sign structures, tri-chord sign structures, and monotube sign structures. Sign structures with typical dimensions and details were selected as prototypes for each of the various types …

Synthesis Study On Use Of Concrete Recycled From Pavement And Building Rubble In The Indiana Highway System, Thomas T. Burke, Menashi D. Cohen, Charles F. Scholer

JTRP Technical Reports

The demolition of buildings and highway pavements in the State of Indiana generates a considerable amount of waste materials. The disposal of these materials causes strain on the existing landfills which are rapidly approaching their full capacity. This study is a synthesis of the information on the use of concrete recycled from pavements and building rubble for use in the Indiana highway system. Test results have shown that recycled pavement concrete made chiefly from broken-up and crushed old concrete aggregate is as good as concrete made from virgin aggregate, and sometimes better. The aggregates made from recycled concrete can be …

Laboratory Evaluation Of Prefabricated Highway Edge Drains, Ahmed Mohamed Elsharief

JTRP Technical Reports

This study evaluated prefabricated highway edge drains to improve the existing practice and to set guidelines for their proper selection. Two primary evaluations received attention: the first was the effect of installation and in service loading on the hydraulic and strength capacities of a prefabricated highway edge drain; and the second was the performance of the geotextile filter.

A limited field evaluation of prefabricated highway drains indicated structural failure of the core and an inefficient geotextile. Based on, the field study, laboratory testing and theoretical modeling, guidelines were given for the strength and hydraulic requirements of the drain. A retention …

The Development Of A Highway Revenue Forecasting Model For Indiana, Amit H. Varma, Kumares C. Sinha, Jeffrey L. Spalding

JTRP Technical Reports

No abstract provided.

Laboratory Study On Properties Of Rubber Soils : Interim Report, Imtiaz Ahmed

JTRP Technical Reports

No abstract provided.

Potential Use Of Tire Rubber And Ebonite In Asphalt: Synthesis Study, Abidin Kaya

JTRP Technical Reports

No abstract provided.