Engineering Commons^™

Test 1276: White Field Boss 2-155 Dsl 18-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 …

Test 1275: White Field Boss 2-135 Diesel 18-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 …

A Comprehensive Study Of Excimer Laser Systems, Robert Ray Butcher

Electrical and Computer Engineering ETDs

Rare gas halogen lasers are finding increasing usage as an intense source of ultraviolet energy. Many applications require a high energy laser capable of operation at reasonably high repetition rates. Elec­trical discharge pumping satisfies these requirements quite nicely, however to date little has been reported on the discharge character­istics of this class of laser. This paper describes a parametric study done on electrical discharge excimer laser systems.

We have designed and tested a flashboard pre-ionized excimer laser utilizing a cable pulse forming network (PFN) for the main discharge. Extensive voltage and current data were taken with various gas mixtures at …

Acuta Enews May 1978, Vol. 7, No.5

ACUTA Newsletters

In This Issue

PRESIDENT'S MESSAGE

PARTY LINE

BITS & PIECE

S SNOWBOARD CONFERENCE '78

MOUTH OF THE SOUTH

POTPOURRI

VIRGINIA VIEW

GETTING THERE FROM HERE--- AT A DISCOUNT

Rayleigh-Debye Scattering With Focused Laser Beams, Lee W. Casperson, Cavour W. Yeh

Electrical and Computer Engineering Faculty Publications and Presentations

A focused beam technique has been developed for diagnosing the characteristics of individual particles within a polydisperse ensemble. In the Rayleigh-Debye approximation the scattered fields are related to the orientation and properties of a scatterer by means of explicit analytic formulas. The results simplify when the particle size is small compared to the minimum beam diameter.

Irish H & V News

Building Services Engineering

No abstract provided.

A Mathematical Model Of Stratified Bi-Directional Flow Through The Railroad Causeway Embankment Of Great Salt Lake, James T. Cameron

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A two-dimensional, finite-element, porous-media flow model is developed to simulate stratified bi-directional flow of brine through the earth embankment carrying the Southern Pacific Railroad across Great Salt Lake. The model is part of a two-year research program whose objective is to develop a computer model of circulation in Great Salt Lake. This overall model is to be used as a predictive device for salinity distributions and circulation patterns in the lake. The porous media flow model is designed to establish flow rates through the Southern Pacific Railroad causeway embankment which traverses the north central part of the lake and divides …

Engineering Properties, And Slope Stability And Settlement Analysis Related To Phosphate Mine Spoil Dumps In Southeastern Idaho, Richard Ellsworth Riker

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The engineering properties of waste spoil from phosphate mines in Southeastern Idaho were determined through field and laboratory testing. The testing included compaction tests, grain size analysis, powder x-ray defraction tests, permeability tests, compression tests, triaxial and direct shear strength tests, and nutrient analyses. Based on these tests, the slope stability and settlement characteristics of phosphate spoil dumps were investigated.

The study showed that the foundation is an important component of the stability of a spoil dump. Hypothetical examples were used to illustrate possible modes of foundation failures. Such failures might occur when weak foundation soils exist or when there …

A Mathematical Model Of The Dispersion Of A Concentrated Substance For Use In The Great Salt Lake's South Arm, Anthony O. Rughellis

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The ability to predict the dispersion of substances in the Great Salt Lake is a requisite towards making responsible management decisions relating to uses of the lake. The lake is a complex terminal body of water and will require a fairly sophisticated mathematical model to properly simulate the dispersion process in the lake. This finite element convection-dispersion model is a first step towards developing a comprehensive model.

The model provides a finite element solution to the two-dimensional convection-dispersion equation and is capable of simulating steady or unsteady-state situations. It utilizes a known velocity field, dispersion coefficients, an introduced substance concentration, …

Geothermal Energy: Heat Extraction From Hot-Dry-Rock Masses In The Presence Of Secondary Thermal Cracks, Yaw-Min Lu

Mechanical Engineering ETDs

Additional heat extraction from geothermal energy reservoirs depends on the feasibility to extend the main, hydraulic fracture through secondary thermal cracks of the adjacent hot rock. When the main, hydraulic fracture is cooled sufficiently, these secon­dary thermal cracks are produced normal to the main fracture surface, As such, both the heat transfer surface area and heat energy available to the fluid circulating through the main, hydraulic fracture system increase.

A Design Study For A Wavy Hydrodynamic Mechanical Face Seal, Raymond Edward Pierce

Mechanical Engineering ETDs

A desirable objective of mechanical face seal design is to achieve the maximum hydrodynamic load support possible while main­taining an acceptable leakage. In this way, mechanical face seal life can be greatly extended as the wear of the seal faces is significantly reduced. It has been shown that circumferentially varying waviness of one of the faces of a mechanical face seal causes such hydrodynamic lubrication.

The objective of this investigation is to examine the performance characteristics of the wavy mechanical face seal by studying the effects of certain design parameters. Seal performance is measured by leakage and wear rate. The …

An Investigation Into The Transport Properties And Kinetic Parameters Of Single Coal Particles During Devolatilization, Gregory Forrest Roach

Chemical and Biological Engineering ETDs

This study focuses on the devolatilization step that occurs in the process of coal gasification. This is a key economic step for both the Lurgi synthetic natural gas process and the in-situ gasification that are being proposed for New Mexican coals. The findings of this study may be used by industry to improve the design and operation of these processes.

The work presented is an investigation into the transport properties and kinetic parameters that govern the extent of pyrolysis for single particles of subbituminous coal from the San Juan Basin in north-west New Mexico. The unique feature of this work …

Axisymmetric Air Jet Impinging On A Hemispherical Concave Plate, Stefan Jachna

Dissertations

This experimental study was conducted on an axisymmetric air jet impinging normally on a smooth, hemispherical, concave plate. The jet Reynolds numbers, based on bulk nozzle velocity and nozzle exit air properties, were between 14,000 and 75,000.

The impingement plate used in this work was a hemispherical surface with the radius of 94 mm.

Calibrated Pitot tubes and a micromanometer were used for pressure and velocity measurements. The Pitot tubes were mounted on precision positioning mechanisms permitting the accurate traversing of any direction in space. The test air flow rate was measured with calibrated rotometers.

The following results of this …

A Simple, Inexpensive Spinning-Drop Interfacial Tensiometer, Humoud S. Al-Rabiah

Chemical and Biological Engineering ETDs

A spinning-drop interfacial tensiometer was designed, built, and tested. The device is very simple, inexpensive to build, and easy to operate compared with other spinningdrop tensiometers.

The tensiometer measures the interfacial tension of liquid-liquid or liquid-vapor systems. Interfacial tensions of three systems were measured to test the device: water-heptane, glycerol-heptane, and glycerol-air.

Experimental results agree with literature values within one percent for the glycerol-heptane system. The variations among the values for the liquid-liquid systems at different rotational speeds are within six percent. Repeated experiments with different drop sizes show that drop size of the glycerol-air system may affect the results. …

Desublimation Of Water Vapor At Low Pressure And Evaporative Freezing Of Seawater, Sun Sea Pao

Chemical and Biological Engineering ETDs

The Vacuum-Freezing Vapor-Desublimation and High Pressure Ice-Melting Process has been developed since 1972. In 1976, Mr. T. C. Chung finished a theoretical study of Low Pressure Water Vapor Desublimation Operation. The writer was a co-worker of Mr. Chung, and had worked with him for the study for four months. The information collected in Mr. Chung's thesis was borrowed and edited as Chapters 1 and 2 in the present thesis. Mr. Chung's theory predicts the rate of water vapor desublimation as a function of the difference between operating temperature and desublimer wall temperature. In the present thesis, experimental rates of desublimation …

Charge Storage Nonvolatile Semiconductor Memory Device, Dae Yeong Joh

Electrical and Computer Engineering ETDs

Semiconductor memory elements have been fabricated on silicon utilizing reactively evaporated TiO₂ as the charge storage insulator medium. The dielectric and charge storage properties of TiO₂ films have been characterized as a function of TiO₂ deposition conditions and post-deposition heat-treatment. Experimental results indicate a strong dependence of the film properties on fabrication process parameter such as oxygen pressure during deposition, substrate temperature, and post-deposition heat-treatment temperature and time. Data taken on the test devices show that both dielectric constant and charge storage properties are enhanced by reactive evaporation of TiO₂ in an oxygen ambient and substrate …

Dielectric Strength Of Sio₂ In A Cmos Transistor Structure, Jerry Malin Soden

Electrical and Computer Engineering ETDs

The maximum dielectric strength distribution of SiO₂ in a CMOS structure is shown to be composed of a primary, normal distribution of high dielectric strength and a low dielectric strength group spread through the lower electric field region. The maximum dielectric strength in the primary distribution is within about 0.5 MV/cm of the dielectric strength reported for uniform thickness SiO₂ in capacitor studies. This indicates the maximum dielectric strength of SiO₂ in a properly fabricated CMOS structure can be nearly as high as the maximum obtainable dielectric strength of uniform SiO₂. The primary dielectric strength …

Structural Design Of Built-Up Plywood Box Beams, Michael J. Sneddon

Graduate Research Papers

The purpose of this study, given the background mentioned above, is to investigate the structural design of built-up plywood box beams and to develop an instructional unit based on their design.

The scope shall be limited to statically determinate beams with either uniformly distributed loads or typical girder loadings.

The resulting instructional unit will be designed as an addition to a course in structural wood design at the vocational-technical/community college level.

Microwave Transmission Through Laser Irradiated Dielectrics, Ronald Robert Delyser

Electrical and Computer Engineering ETDs

An investigation is made of microwave transmission through two types of dielectrics while being irradiated by a 15 Kw, CO₂ continuous wave laser. The two materials, a high silica ceramic and a fiber­glass laminate, present two different problems for solution of their microwave transmission characteristics while being subjected to high intensity continuous wave irradiation.

The high silica ceramic was found to exhibit a slightly reduced transmission coefficient with an accompanying change in phase delay due to ablation of the material during laser irradiation. As much as -4db loss with a phase delay of +30° is observed at an intensity …

Buckling Of Stiffened Plates And Shells, William De La Garza

Civil Engineering ETDs

The emphasis in this dissertation is the determination of buckling loads on many types of structures. The available solutions are usually written in a complex form that requires large amounts of time in order to find the buckling loads. For stiffened structures the use of finite difference calculus will provide a vehicle for obtaining solutions that are not as complex. In addition, the use of a reasonable approximation for the stiffener behavior allows the solution to be written in closed from. Direct substitution of the elastic and geometric properties of the stiffeners gives the buckling loads. The application of finite …

Cpacs Happenings (April 1978 Newsletter), College Of Public Affairs And Community Service, University Of Nebraska At Omaha

CPACS Newsletters

The College of Public Affairs and Community Service (CPACS) newsletter that reported on the news, collaborations, events, and general happenings of the UNO College of Public Affairs and Community Service. This newsletter has had many names and variations over the years including SPACS Newsletter (1973); Newsletter of the College of Public Affairs and Community Service (1973-1974): Happenings (1974-1980s); and the current e-newsletter titled the CPACS Collective (2021-)

Tests On Puddle Weld Connections, William Mcguire, J. W. Struble, Teoman Peköz

CCFSS Library (1939 - present)

PREFACE This non-interpretive report contains the results of 90 tests on circular and oblong puddle weld connections. The connections involved test specimens constructed of flat steel plates and thin connecting sheets of varying thicknesses (10 to 28 gage) with the welds to be studied forning the bond between them. Testing consisted of tensile loading to ultimate failure. This work was carried out under contract with the Engineering Division of the American Iron and Steel Institute.

Ole Miss Engineer 1978

Ole Miss Engineer

No abstract provided.

Affinity Of Roadside Soils For Lead, Zinc, And Chromium, John H. Bell

Retrospective Theses and Dissertations

Highways are known to be a source of several toxic pollutants including the heavy metals lead, zinc and chromium. The need to manage highway runoff in a manner which reduces or eliminates the loading of heavy metals to receiving waters is evident, but more research has been required to develop cost-effective ways of meeting this need. Recent studies have indicated that the soil is a significant "sink" for heavy metals, allowing speculation that management practices which make use of the soil to retain metals from highway runoff should be employed. The purpose of this study is to evaluate the ability …

Sensitivity Analysis Of Stormwater Runoff Using The "Bmp" And "Nonpt" Computer Programs, George D. Flatt

Retrospective Theses and Dissertations

No abstract provided.

Irish H & V News Incorporating Zone

Building Services Engineering

No abstract provided.

Acoustic Emission And Fatigue Characteristics Of Typical Bridge Steels, Theodore Hopwood Ii, James H. Havens

Kentucky Transportation Center Research Report

Acoustic emission monitoring was used during tensile tests of low-carbon structural steels to determine the physical characteristics of the acoustic emission phenomena. Results indicate that acoustic emissions are caused by micro-plastic deformation processes (i.e., dislocation motion).

A series of axial-fatigue tests was performed on several types of structural steels, some of which had extensive service in bridges. There was no apparent relation between specimen load histories and subsequent performance in fatigue tests. Tensile tests of specimens subjected to extensive fatigue testing, at stresses below the yield strength of the material, revealed no major difference in mechanical properties or acoustic emission …

Analysis Of Moisture Absorption And Diffusion In Fiber Reinforced Polymeric Resin-Matrix Composite Materials, Stephen Stern Tompkins

Mechanical & Aerospace Engineering Theses & Dissertations

The diffusion of moisture through fiber reinforced polymeric-matrix composite materials has been studied analytically. The diffusion in the orthotropic, nonhomogeneous material was modeled, in detail, with a two-dimensional transient diffusion analysis. An effective diffusivity for the composite was determined in terms of the fiber volume fraction and the resin diffusivity. This effective diffusivity is in better agreement with recent data than those previously determined using less complex models.

The influence of both material and environmental parameters on the moisture content of the composite was determined analytically. Predicted moisture contents were compared over a wide range of values for emittance, solar …

Studies Of Fracture And Deformed Surfaces Of High Strength Aluminum Alloys By X-Ray Diffraction, Tamma K. Kumar

Mechanical & Aerospace Engineering Theses & Dissertations

X-ray observations of fatigue fracture and deformed surfaces of 7075-T6 aluminum were conducted in this study. The (111) and (222) diffraction peaks were obtained from the fractured and deformed surfaces. It was observed that in comparison with the base metal, the fracture exhibited line broadening similar to that due to cold working. The broadening is indicative of plastic deformation in the vicinity of the advancing crack tip during the fracture process. Also the different regions of fracture exhibited varying degrees of line broadening. With respect to the fatigue crack, the slow crack growth region showed a greater broadening, and, hence, …

Simulation Of Mechanical Rotation By Optical Rotation: Application To The Design Of A New Fourier Photopolarimeter, R. M.A. Azzam

Electrical Engineering Faculty Publications

The mechanical rotation of an optical element around the axis of a beam of polarized light can be easily simulated by using the phenomenon of optical rotation. Because optical rotation can be magnetically or electrically induced, virtually any kind of mechanical rotation can be mimicked. This interesting principle is applied to the design of a new Fourier photopolarimeter that uses an oscillating-azimuth retarder (OAR). The OAR consists of a quarter-wave plate surrounded by two ac-excited Faraday cells that produce equal and opposite sinusoidal optical rotations. Analysis of the operation of this polarimeter of no moving parts proves its ability to …