Engineering Commons^™

Area Conservation Tillage Meetings-A Successful Educational Program, Elbert C. Dickey, Paul J. Jasa, David P. Shelton, Robert Grisso, Keith Glewen

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Interest in conservation tillage began to increase in the early 1980s, and farmers wanted information on how to adopt and manage various tillage and planting systems. Area conservation tillage meetings were developed by the University of Nebraska Cooperative Extension to provide the needed information on a regional basis. Local extension agents and Soil Conservation Service personnel helped extension specialists determine program content. The multidisciplinary meetings included farmer presentations and allowed space and time for commercial exhibits. About 80% of respondents to meeting evaluations indicated they planned to change their tillage practices as a result of the information presented.

Dna Mapping Algorithms: Clone Sequencing, Judith H. Lewis, Will Gillett

All Computer Science and Engineering Research

The DNA restriction mapping problem can be abstracted to the Shortest Common Matching String problem by viewing the restriction fragment lengths as symbols and the clones as bags. The Shortest Common Matching String problem can be decomposed into the Bag Sequencing problem and the Symbol Sequencing problem. All three of these problems have bene shown to be NP-hard. Rhee has proposed a family of greedy algorithms to compute polynomial time approximations to the Bag Sequencing problem, which produced surprisingly good performance results on abstracted data. In the test data generated by Rhee for pragmatic analysis, the symbols in bags represented …

Sol-Gel Derived, Air-Baked Indium And Tin Oxide Films, Douglas M. Mattox

Materials Science and Engineering Faculty Research & Creative Works

A sol-gel derived, transparent, electrically conducting tin-doped In₂O₃ film system has been developed which only requires air baking. The films approximate the properties of sputtered and hot-sprayed films but are simpler and less expensive to apply by dipping and spinning procedures. Substrate sodium interference was seen to be minimal. © 1991.

Composite Stock Cutting Through Simulated Annealing, Pipatpong Poshyanonda, Cihan H. Dagli

Computer Science Technical Reports

This paper explores the use of Simulated Annealing as an optimization technique for the problem Composite Material Stock Cutting. The shapes are not constrained to be convex polygons or even regular shapes. However, due to the composite nature of the material, the orientation of the shapes on the stock is restricted. For placements of various shapes, we show how to determine a cost function, annealing parameters, and performance.

Composite Stock Cutting Through Simulated Annealing, Pipatpong Poshyanonda, Cihan H. Dagli

Computer Science Technical Reports

This paper explores the use of Simulated Annealing as an optimization technique for the problem Composite Material Stock Cutting. The shapes are not constrained to be convex polygons or even regular shapes. However, due to the composite nature of the material, the orientation of the shapes on the stock is restricted. For placements of various shapes, we show how to determine a cost function, annealing parameters, and performance.

Temperature Dependence Of Optical Properties Of Gaas, Huade Yao, Paul G. Snyder, John A. Woollam

Department of Electrical and Computer Engineering: Faculty Publications

Pseudodielectric functions (ε) = (ε₁) + i (ε₂) of GaAs were measured by spectroscopic ellipsometry (SE), in the range of 1.W.45 eV, at temperatures from room temperature (RT) to ~610 ° C. A very clean, smooth surface was obtained by first growing an epitaxial layer of GaAs on a GaAs substrate and immediately capping it with a protective layer of arsenic. The cap prevented surface oxidation during transport to the measurement chamber, where it was evaporated under ultrahigh vacuum at ~350 °C. Room-temperature SE results from this surface are in good agreement with those in the …

Gaseous Component Identification With Polymeric Film Sensor, Edward S. Kolesar Jr.

AFIT Patents

A sensor having an interdigitated gate electrode field effect transistor (IGEFET) coupled to an electron beam evaporated copper phthalocyanine thin film is used to selectively detect parts-per-billion concentration levels of atmosphere contaminants such as nitrogen dioxide (NO₂) and diisopropyl methylphosphonate (DIMP). The sensor is excited with a voltage pulse, and its time- and frequency-domain response are examined. The envelopes of the magnitude of the normalized difference frequency spectrums reveal features which unambiguously distinguish the NO₂ and DIMP exposures.

Acuta Enews September 1991, Vol. 20, No. 9

ACUTA Newsletters

In This Issue

0+ fraud alive and well

AOS rules don't move north

Call screening not mandated

Workshop in Atlanta

Five Ps paying off

Business Manager profile

Design Of Automotive Structural Components Using High Strength Sheet Steels Structural Strength Of Cold-Formed Steel Beams Under Dynamic Loads, Chi-Ling Pan, Wei-Wen Yu

CCFSS Library (1939 - present)

INTRODUCTION It has long been recognized that material properties and stress-strain relationships of sheet steels can be influenced by the strain rate. A considerable amount of theoretical and experimental research have been undertaken in the past to study material properties and the behavior of structures under dynamic loads and impact loads. In view of the fact that in the current AISI Automotive Steel Design Manual 1, the design criteria for effective design width are based on the test results under static loading condition, the objective of this investigation was to study the validity of these effective design width formulas for …

The Calendar - September 1991, Nova University

The Calendar

No abstract provided.

Analysis Of Traffic Accident Data In Kentucky (1986-1990), Kenneth R. Agent, Jerry G. Pigman

Kentucky Transportation Center Research Report

This report includes an analysis of traffic accident data in Kentucky for the years of 1986-1990. A primary objective of this study was to determine average accident statistics for Kentucky highways. Average and critical number and rates of accidents were calculated for various types of highways in rural and urban areas. These data can be used in Kentucky's procedure to identify locations that have abnormal rates or numbers of accidents.

Another objective of this study was to provide data which can be used in the preparation of the problem identification portion of Kentucky's Annual Highway Safety Plan. County and city …

Laser Bandwidth-Induced Fluctuations In The Intensity Transmitted By A Fabry-Perot Interferometer, Gerhard Klimeck, Daniel Elliott, M. Hamilton

Birck and NCN Publications

We have measured the power spectrum of the intensity Auctuations of light transmitted by a Fabry- Perot interferometer when the input field is the real Gaussian field. The real Gaussian field is a field characterized by real, random (Gaussian) amplitude Auctuations. The bandwidth of the real Gaussian field was varied, taking on values less than that of the interferometer, as well as greater. Comparisons of the measured spectra with calculated spectra are quite satisfactory. Of special interest is a feature in the spectra centered at the laser-interferometer detuning frequency.

Evaluation Of Stamark Brand Bisymmetric 1.75 Grade Pavement Marking Tape, Kenneth R. Agent

Kentucky Transportation Center Research Report

The objective of this project was to evaluate the performance of Stamark Brand Bisymmetric 1.75 Grade pavement Marking Tape (Series 320) on a large-scale installation on Interstate 24 in McCracken County. The evaluation consisted of periodic inspection of the tape to determine its durability, appearance, and reflectivity.

The tape has demonstrated good performance after two years in service. No durability problems were noted. While the appearance of the tape was not as bright as a typical traffic paint, it was adequate. The tape has maintained a high level of reflectivity. The performance of the material would potentially warrant additional use …

1991 Safety Belt Usage Survey And Evaluation Of Effectiveness In Kentucky, Kenneth R. Agent

Kentucky Transportation Center Research Report

The objective of the survey was to establish 1991 safety belt and child safety seat usage rates in Kentucky. Data were collected at 100 sites and combined based on vehicle miles traveled for a given type of highway, rural or urban location, and county population category. Also included in this report is an analysis of accident records evaluating the effectiveness of safety belts.

Statewide usage rates were 39 percent for drivers and front-seat passengers (over 19 years of age) and 57 percent for children under four years of age (front and rear seats). Driver usage rates had increased significantly in …

Analysis Of Transport Phenomena In The Coating Of Fibers By Cvd, J H. Scholtz, J E. Gatica, Hendrik J. Viljoen

Papers in Materials Science

Inorganic coated fibres produced by chemical vapour deposition find several technological applications. In this CVD process, a filler core is mounted in a reactor between two electrodes. Reactive gases flow over the substrate and react near or on the fibre surface to form the desired coating. Experience has showed that, quality deposition can only be obtained over a small range of the governing parameters: these parameters are, however, difficult to control. In the present, study a mathematical model is developed for the reactor configuration under consideration. The different mass and energy transport mechanisms are compared and their influence on the …

A Summary Of Highway Revenues, Expenses And Distributions: 1984 Through 1991, Herpicc

Indiana Local Technical Assistance Program (LTAP) Publications

This report shows the history of receipts, expenses and distributions of revenues that provide funding to all local governments for highway, road and street work.

Field-Equation Approximations And Amplification In High-Gain Lasers: Numerical Results, Lee W. Casperson

Electrical and Computer Engineering Faculty Publications and Presentations

It has recently been shown that a field-equation time-derivative approximation that is commonly used in studies of laser-oscillator dynamics is not necessary and can lead to significant errors for some lasers. A related space-derivative approximation is widely used in studies of steady-state laser amplifiers. A more rigorous amplifier formalism is developed here, and the results are exact solutions of Maxwell’s equations. The improved model predicts a spatial instability, single mirror oscillation, and other interesting field behavior.

Field-Equation Approximations And Amplification In High-Gain Lasers: Analytical Results, Lee W. Casperson

Electrical and Computer Engineering Faculty Publications and Presentations

In a related study the equations governing a high-gain laser amplifier have been solved numerically without making the usual slowly-varying-amplitude derivative approximation in Maxwell’s equations, and thus the field amplitudes are not restricted to vary negligibly in a distance of one wavelength. The results reveal an instability that involves reflections and oscillatory growth of perturbations away from steady state. In the present study steady-state solutions of the field equations are obtained analytically, and transformations are described for converting the equations to alternative intensity-equation sets. These intensity equations are linearized and solved for the growth rate and oscillation period of the …

Composition And Method For Radiation Synovectomy Of Arthritic Joints, D. E. Day, Gary J. Ehrhardt

Materials Science and Engineering Faculty Research & Creative Works

A method for preparing nonradioactive microspheres adapted for radiation synovectomy of arthritic joints in a mammal involves forming the microspheres by doping a biodegradable glass material which may be lithium or potassium silicate, lithium or potassium aluminosilicate, lithium or potassium aluminoborate, lithium or potassium germanate or lithium or potassium alumino- germanate with an isotope which may be samarium, holmium, erbium, dysprosium, rhemium or yttrium so that the isotope is chemcially dissolved in and distributed uniformly throughout the glass material. The doped glass material is then treated with an acid wash to produce a thin layer on the surface thereof and …

Integrated Neural Network And Machine Vision Approach For Intelligent State Identification, Cihan H. Dagli, Timothy Andrew Bauer

Engineering Management and Systems Engineering Faculty Research & Creative Works

An interfacing of neural networks (NNs) and machine vision to provide the next state of a system given an image of the present state of the system is presented. This interfacing is applied to a loading operation. First, a NN is trained for part recognition under conditions of rotation, location, object distortion, and background noise given an image of the part. Then, a second NN, given the output of the first NN and an image of a pallet being loaded, is trained for optimal part loading onto the pallet under conditions of noise in the image. The paradigm used is …

Acuta Enews August 1991, Vol. 20, No. 8

ACUTA Newsletters

In This Issue

President's column

Business meeting

Regional meetings

User groups

Director's column

Workshop in Atlanta

Electromagnetic Field Plot Of An Inductive Window By The Moment Method, John R. Natzke, Mark R. Wolski, Thomas Koryu Ishii

Faculty Publications - Department of Electrical Engineering and Computer Science

A moment method is used to plot the electromagnetic field of an inductive window in a TE10 -mode rectangular waveguide. Green's dyadic functions are derived based on Tai's approach, which is a modified form of Hansen's vector wave functions. Based on the computed electric fields, the S matrix and the equivalent aperture reactance of the waveguide window are calculated. This calculation agrees with the previously published closed-form results of Marcuvitz.

Ccfss News August 1991, Wei-Wen Yu Center For Cold-Formed Steel Structures

CCFSS Newsletters (1999 - 2008)

No abstract provided.

Efficient Single-Heterojunction Al0.27Ga0.73As/Gaas P-I-N Photodiodes With 22-Ghz Bandwidths, C. Johnson, S. Sloan, D. M. Braun, J. L. Russell, M. Zurakowski, M. Lightner, F. Kellert, G. Patterson, R. Koo, Dennis J. Derickson, J. E. Bowers

Electrical Engineering

A report is presented on the design, fabrication, testing, and modeling of single-heterojunction Al_0.27Ga_0.73As/Ga p-i-n photodiodes for use as components in optical receivers. The photodiodes are grown by molecular beam epitaxy and fabricated as 1100-μm² mesa structures. At 5-V reverse bias and 850 nm, 100 fF of capacitance, 90 pA of leakage current, 73% external quantum efficiency, <2% reflectivity, and 22-GHz bandwidths are typically measured.

Evaluation Of Headwalls And Outlets For Geocomposite Edge Drains On I-75 And I-71, L. John Fleckenstein, David L. Allen, Jack A. Harison

Kentucky Transportation Center Research Report

Longitudinal, round, perforated pipe edge drains have been used along Kentucky roadways for approximately two decades. Panel (fin) edge drains were first used in Kentucky in 1984. Most of these edge drains were installed on the Interstate and Parkway systems.

Several problems related to the drains have been noted in the last seven years. A number of these problems have been observed to be related to flexible outlet pipes and headwalls.

A recent study was initiated to evaluate headwalls and outlets on I-75 from Lexington, Kentucky to Cincinnati, Ohio (approximately 70 miles) and on I-71 from Louisville, Kentucky to I-75 …

Roughness Coefficients For Selected Residue Materials, John E. Gilley, Eugene R. Kottwitz, Gary A. Wieman

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Analysis of surface runoff on upland areas requires identification of roughness coefficients. A laboratory study is conducted to measure Darcy-Weisbach and Manning roughness coefficients for corn, cotton, peanut, pine needles, sorghum, soybeans, sunflower, and wheat residue. Varying rates of flow are introduced into a flume in which selected amounts of residue are securely attached. Roughness coefficients are calculated from measurements of discharge rate and flow velocity. The laboratory data are used to derive regression equations for relating roughness coefficients to Reynolds number and either percent residue cover or residue rate. Separate equations are developed for Reynolds number values from 500 …

Comparing Simulated And Experimental Hysteretic Two-Phase Transient Fluid Flow Phenomena, R. J. Lenhard, J. C. Parker, Jagath J. Kaluarachchi

Civil and Environmental Engineering Faculty Publications

A hysteretic model for two-phase permeability (k)-saturation (S)-pressure (P) relations is outlined that accounts for effects of nonwetting fluid entrapment. The model can be employed in unsaturated fluid flow computer codes to predict temporal and spatial fluid distributions. Consideration is given to hysteresis in S-P relations caused by contact angle, irregular pore geometry, and nonwetting fluid entrapment effects and to hysteresis in k-Srelations caused by nonwetting fluid entrapment effects. An air-water flow experiment is conducted with a 72-cm vertical soil column where the water table is fluctuated to generate scanning S-P paths. Water contents are measured via a gamma radiation …

Antique Farm Machinery And Equipment Commission July, 1991, Tractor Museum

Lester F. Larsen Tractor Museum: Planning and Development Documents

No abstract provided.

Optimal Aquifer Planning With Salt Water Boundary, Richard C. Peralta, Shu Takahashi

Civil and Environmental Engineering Faculty Publications

Optimal sustained-yield pumping strategies were developed for the irrigated and industrialized eastern shore of the Great Salt Lake. The combined optimization and simulation model, in which steady-state, finite difference, quasi-three-dimensional ground water flow equations were embedded as constraints, computes the optima,! distribution for sustainable annual ground water pumping rates for alternative scenarios. 1. The model deals with management of a large, multilayer, confined/unconfined (linear/nonlinear) aquifer system. 2. The research can help manage water in the study area where· the demand for water of sufficient quality and quantity is increasing due to urbanization.

Solutal Partition Coefficients In Nickel-Based Superalloy Pwa-1480, Surendra N. Tewari, M. Vijayakumar, James E. Lee, P. A. Curreri

Chemical & Biomedical Engineering Faculty Publications

Solutal profiles in dendritic single-crystal specimens of PWA-1480 nickel-base superalloy, which were directionally solidified and quenched, were examined on several transverse cross-sections to obtain the partition coefficients. Similar to their nickel-base binaries, the partition coefficients of tantalum, titanium, and aluminum were found to be less than unity; those of tungsten and cobalt were greater than unity. The partition coefficients were temperature independent in the range 1584-1608 K. The contribution of solid-state diffusion to microsegregation was observed to be negligible.