Engineering Commons^™

Material Handling In A Flexible Manufacturing Systems Processing Part Families, Paul Savory, Gerald Mackulak, Jeff Cochran

Department of Industrial and Management Systems Engineering: Faculty Publications

The objective of this simulation study is to analyze the system performance of a six machine flexible manufacturing system cell in which a material handling system is to be incorporated. The analysis focuses on determining the production potential of the cell by grouping common parts into "families". To accomplish this, computer simulation models are developed using the SIMAN simulation language.

Initially the manufacturing cell is modeled with no material handling system to get an upper bound estimate of production output. We next explore the impact that an automatic guided vehicle (AGV) has on system performance of the manufacturing system cell. …

Acuta Enews December 1991, Vol. 20, No. 12

ACUTA Newsletters

In This Issue

10-XXX gives occasion for fraud

President's Message

YaleNET, a variety of services

Think ahead to prevent fraud

MOREnet links 12 campuses

Positions available

Test 1656: Ford 5640 (16x4) Diesel 16-Speed, Nebraska Tractor Test Lab

Nebraska Tractor Tests

EXPLANATION OF THE TEST PROCEDURE General Tractors are tested at the University of Nebraska according to the Agricultural Tractor Test Code approved by the American Society of Agricultural Engineers and the Society of Automotive Engineers or official Nebraska test procedure. The manufacturer selects the tractor to be tested and certifies that it is a stock model. Each tractor is equipped with the common power consuming accessories such as power steering, power lift pump, generator, etc., if available. Power consuming accessories may be disconnected only when the means for disconnecting can be reached from the operating station. An official representative of …

Solder/Polymer Composite Paste And Method, Ravi F. Saraf

Department of Chemical and Biomolecular Engineering: Patents

An improved solder/polymer fluxless composite paste interconnection material having a low reflow temperature to form electrical contacts having good bonding strength and low contact resistance. The present pastes comprise a major proportion of a meltable metal alloy powder filler, free of noble metals and preferably free of lead, a minor proportion of a solution of a temperature-stable thermoplastic polymer having a softening temperature above the melting temperature of the metal powder filler in a volatile solvent which evaporates during reflow, and a minor proportion of a fluxing agent having a boiling point lower than the reflow temperature of the composition …

Acuta Enews November 1991, Vol. 20, No. 11

ACUTA Newsletters

In This Issue

President's message

Distance learning in Maine

FCC backs phone-line video

Pooling purchasing power

Area code shortage

Positions available

Acuta Enews October 1991, Vol. 20, No. 10

ACUTA Newsletters

In This Issue

President's message

Wireless alternative to cable

AT&T donates computers

ACUTA budget for 1991-92

Voice messaging is "hit"

Publications Editor profiled

A Conservation Tillage Educational Program, Elbert C. Dickey, Paul J. Jasa, David P. Shelton

Biological Systems Engineering: Papers and Publications

An educational program was conducted to enhance the adoption of conservation tillage practices in targeted areas to reduce soil erosion and on-farm fuel use. Traditional extension methods such as meetings, field days, demonstrations, and plots were used extensively. In addition, the following nontraditional educational methods were used to achieve project objectives: targeting high priority areas, local program guidance committees, surveys to evaluate perceptions and use of conservation tillage, employment of extension assistants to work in the target areas, use of a rainfall simulator to demonstrate the effectiveness of residue cover in reducing erosion, and small group or "coffee shop" meetings …

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

Biological Systems Engineering: Papers and 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.

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 …

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

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 …

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

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

Biological Systems Engineering: Papers and 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 …

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

Lester F. Larsen Tractor Museum: Planning and Development Documents

No abstract provided.

Acuta Enews July 1991, Vol. 20, No. 7

ACUTA Newsletters

In This Issue

ACUTA Forum

Unblocking 1-0-XXX

President's farewell

Affordable fiber to the desk

Value of utility bill audits

$60 million math/science network

Tractor Museum Committee Establishment 1991, Tractor Museum

Lester F. Larsen Tractor Museum: Planning and Development Documents

No abstract provided.

Acuta Enews June 1991, Vol. 20, No. 6

ACUTA Newsletters

In This Issue

Panel to focus on fraud

Interactive video bandwidth

Aggregator requirements

Telex can still be useful

Penn State still pioneering

Positions availabe

Acuta Enews May 1991, Vol. 20, No. 5

ACUTA Newsletters

In This Issue

Golf outing set for St. Louis

Network ties islands together

Reorganization at Chicago

Recycling phone books

Party Line

Call for nominations

Hydraulic Roughness Coefficients As Affected By Random Roughness, John E. Gilley, S. C. Finkner

Biological Systems Engineering: Papers and Publications

Random roughness parameters are used to characterize surface microrelief. In this study, random roughness was determined following six selected tillage operations. Random roughness measurements agreed closely with values reported in the literature.

Surface runoff on upland areas is analyzed using hydraulic roughness coefficients. Darcy-Weisbach and Manning hydraulic roughness coefficients were identified in this investigation on each soil surface where random roughness values were determined. Hydraulic roughness coefficients were obtained from measurements of discharge rat巳and flow velocity.

The experimental data were used to derive regression relationships which related Darcy-Weisbach and Manning hydraulic roughness coefficients to random roughness and Reynolds number. Random …

Optical And Magneto-Optical Characterization Of Tbfeco Thin Films In Trilayer Structures, William A. Mcgahan, Ping He, Liang-Yao Chen, Sal Bonafede, John A. Woollam, F. Sequeda, T. Mcdaniel, H. Do

Department of Electrical and Computer Engineering: Faculty Publications

A series of TbFeCo films ranging in thickness from 100 to 800 Å have been deposited in trilayer structures on silicon wafer substrates, with S₃N₄ being employed as the dielectric material. These films have been characterized both optically and magneto-optically by variable angle of incidence spectroscopic ellipsometry, normal angle of incidence) reflectometry, and normal angle of incidence Kerr spectroscopy. From these measurements, the optical constants n and k have been determined for the TbFeCo films, as well as the magneto-optical constants Ql and Q2. Results are presented that demonstrate the lack of dependence of these …

Diffraction Studies On Ni-Co And Ni-Cr Alloy Thin Films, A. R. Sethuraman, R. J. De Angelis, P. J. Reucroft

Nebraska Center for Materials and Nanoscience: Faculty Publications

Alloy films of Ni-Co and Ni-Cr of compositional ratios 1:1, 1:3, and 3:1 deposited by vapor deposition were studied by Transmission Electron Microscopy (TEM) and X-Ray Diffraction (XRD). Results of TEM analysis on the Ni-Co alloy films indicated that the films were face-centered cubic (fee) in structure. XRD results confirmed the TEM observations. TEM analysis of Ni-Cr alloy films showed that the films were bodycentered cubic (bec) in structure. With increase in the Cr content more than 25%, the material contained a higher fraction of an amorphous phase. XRD studies provide limited information owing to the quasi-amorphous structure of the …

Acuta Enews April 1991, Vol. 20, No. 4

ACUTA Newsletters

In This Issue

ACUTA Forum

Travel cards save money

Reorganization at Chicago

Regional Directors elected

Enchancing campus safety

Drew's Knowledge Initiative

Magneto-Optical Kerr Effect And Perpendicular Magnetic Anisotropy Of Evaporated And Sputtered Co/Pt Multilayer Structures, Ping He, William A. Mcgahan, John A. Woollam, F. Sequeda, T. Mcdaniel, H. Do

Department of Electrical and Computer Engineering: Faculty Publications

Thin and ultrathin Co/Pt multilayered structures have been prepared on glass substrates by electron-beam evaporation at room temperature and by sputtering at various substrate temperatures and sputtering pressures. Perpendicular magnetic anisotropy was found in samples with Co/Pt bilayer thicknesses near 3 Å/l0 Å and total thicknesses of the layer stack of no greater than 300 Å. X-ray diffraction was performed on the samples to determine layer spacing and integrity, and possible crystallinity of films. Crystalline structures in the interface between the Co and Pt layers were found and identified. The effects of sputtering parameters, such as pressure and substrate temperature, …

Acuta Enews March 1991, Vol. 20, No. 3

ACUTA Newsletters

In This Issue

Telecom graduate study

Greenville Tech outgrows PBX

World-calling discounts

Call for Presentations

Update on Hawaii

Listing of exhibitors

Acuta Enews February 1991, Vol. 20, No. 2

ACUTA Newsletters

In This Issue

ACUTA gains new tax status

Stopping a runaway dialer

Just what is an engineer?

FCC ruling awaited

Party Line

In-house accounting

Study Of Ingaas-Based Modulation Doped Field Effect Transistor Structures Using Variable-Angle Spectroscopic Ellipsometry, S. A. Alterovitz, R. M. Sieg, H. D. Yao, Paul G. Snyder, John A. Woollam, J. Pamulapati, P. K. Bhattacharya, P. A. P. A. Sekula-Moise

John A. Woollam Publications

Variable-angle spectroscopic ellipsometry was used to estimate the thicknesses of all layers within the optical penetration depth of InCaAs-based modulation doped field effect transistor structures. Strained and unstrained InGaAs channels were made by molecular beam epitaxy (MBE) on InP substrates and by metal-organic chemical vapor deposition on GaAs substrates. In most cases. ellipsometrically determined thicknesses were within 10% of the growth-calibration results. The MBE-made InCaAs strained layers showed large strain effects, indicating a probable shift in the critical points of their dielectric function toward the InP lattice-matched concentration.

Forming Fine Particles, Dennis R. Alexander

Department of Electrical and Computer Engineering: Faculty Publications

To alter feedstock material, the material is exposed to laser radiation applied at a selected angle of incidence, intensity and wavelength related to the refractive index of the feedstock material. Fine uniform particles may be formed through vapor explosion and/or plasma formation and used by this method to coat surfaces, such as with paint or adhesive or to suply uniform small particles to a heat engine. Moreover, moving materials such as a column of liquid may be subjected to high internal pressure and temperature for creating physical and chemical changes.

Acuta Enews January 1991, Vol. 20, No. 1

ACUTA Newsletters

In This Issue

ECCI founder honored

Pocket phone test at UGA

Giving pays off for Emory

Digitizing X-rays

Illicall lists rates

Party Line

Bioconcentrations Of Heavy Metals Copper, Chromium (Tot), Lead, Zinc, Nickel And Mercury In The Missouri River 1991

US Army Corps of Engineers

The presence of heavy metals within aquatic environments can be attributed to sources such as industry, municipal discharges, agriculture and natural processes which release various amounts into natural systems. Metals such as copper, zinc and chromium are listed as essential micronutrients for many plant and animal species. Of potential concern, however, is the tendency of heavy metals to accumulate within the food webs of ecosystems. Classified as biologically hard to degrade, heavy metals may concentrate to significant amounts within the trophic levels of a particular ecosystem. At these increased concentrations many of these heavy metals become toxic to living organisms. …

Subsoiling, Contouring, And Tillage Effects On Erosion And Runoff, Paul J. Jasa, Elbert C. Dickey

Biological Systems Engineering: Papers and Publications

A study to evaluate the effectiveness of subsoiling on reducing soil erosion and water runoff from continuous com production was conducted. A rotating boom rainfall simulator was used on replicated treatments having either preplant in-row subsoiling or postplant between-row subsoiling used in both tilled and untilled surface conditions. Tilled and untilled treatments without subsoiling were used as checks. These six treatments were used up-and-downhill and on the contour.

Subsoiling reduced the rate of water runoff but did not significantly reduce the soil erosion rate after equilibrium had been reached between water application and runoff rates. Surface condition and farming direction …