Engineering Commons^™

Studies Of Vibrational Surface Modes In Ionic Crystals. I. Detailed Shell-Model Studies For The Unrelaxed (001) Face Of Seven Crystals Having The Rocksalt Structure, T. S. Chen, F. W. De Wette, G. P. Alldredge

Mechanical and Aerospace Engineering Faculty Research & Creative Works

We present a comprehensive, unified account of the lattice dynamics of unrelaxed (001) faces of seven crystals having the rock salt structure, three of which have an absolute gap between the acoustical and optical bulk bands (RbF, RbCl, and NaI) and four of which have overlap between these bulk bands (NaF, NaCl, LiF, and MgO). The results are obtained from calculations of the normal modes of a thin crystal film in which the ionic interactions are described by the rigid-shell model. An outline of the formulation of the shell model for the film is given, and the rapid convergence of …

Modeling Soil Water Movement Into Plant Roots, D. C. Slack, C. T. Haan, Larry G. Wells

Biosystems and Agricultural Engineering Faculty Publications

Mathematical model was developed which describes uptake of water by plant roots as a function of leaf and soil water potentials. The model was used to estimate transpiration from corn grown in a controlled environment under soil drying conditions. The model predicted daily transpiration quite well for the period modeled.

A Laser Hydrophone, Steven Kenneth Barnoske

Retrospective Theses and Dissertations

This report proposes a novel technique for measuring of acoustic fields in water. A Laser Hydrophone is proposed taking advantage of the properties of Total Internal Reflection. A theoretical analysis of the idea is presented followed by a prediction of the operating characteristics of an actual system. Actual data were taken with the proposed system and it is compared to the predicted.

Finite Element Analysis Of Cylindrical Inclusions, Thomas L. Wade

Retrospective Theses and Dissertations

This paper presents a parametric study of the stresses in a matrix near a cylindrical inclusion. The Texas Grain Analysis Program (TEXGAP), a finite element approach, is used to model the problem. Eight different models are investigated which establish the stress effects of varying interlayer thickness, varying modulus of elasticity of inclusions and interlayers, and element size. The results, presented as plots of axial stresses, show a definite lowering of the stress in the area of inclusion termination as the interlayer thickness is increased from zero. A further stress decrease is noted with the addition of some inclusion elasticity. Similarly, …

Load Forecasting For An Electrical Utility, Thomas Edmund Washburn

Retrospective Theses and Dissertations

No abstract provided.

Direct Solution Of The Isothermal Gibbs‐Duhem Equation By An Iterative Method For Binary Systems, J. A. Martinez‐Ortiz, David B. Manley

Chemical and Biochemical Engineering Faculty Research & Creative Works

No abstract provided.

Multiple High Voltage Output Dc-To-Dc Power Converter, Don Cronin, Bertrand F. Farber, Hartmut K. Gehm, Daniel S. Goldin

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Disclosed is a multiple output DC-to-DC converter. The DC input power is filtered and passed through a chopper preregulator. The chopper output is then passed through a current source inverter controlled by a squarewave generator. The resultant AC is passed through the primary winding of a transformer, with high voltages induced in a plurality of secondary windings. The high voltage secondary outputs are each solid-state rectified for passage to individual output loads. Multiple feedback loops control the operation of the chopper preregulator, one being responsive to the current through the primary winding and another responsive to the DC voltage level …

Improving Qpsk Transmission In Band-Limited Channels With Interchannel Interference Through Equalization, S. H.R. Raghavan, Rodger E. Ziemer

Electrical and Computer Engineering Faculty Research & Creative Works

This paper describes the use of equalization in conjunction with channel filtering to improve QPSK transmission subject to both InterSymbol interference (ISI) and interchange interference (ICI). Performance bounds are computed using the nonclassical Gauss-quadrature rule (GQR) method. The signal-to-noise ratio (SNR) gain due to linear equalization over Non equalization is thereby obtained and presented. The performance of a linear equalizer thus obtained is compared with the Viterbi algorithm sequence estimator (VASE). In the absence of bounds for the VASE receiver under the channel conditions considered, simulation results are used to make the comparison. With a possible difference in the accuracies …

The Manufacturing Of Cement In Northern Iowa And The Strength Of Selected Concrete Mixes Using Compression Testing, James E. Gephart

Graduate Research Papers

Cement manufacturing is a process that has been developed and refined during past centuries. The end result of this process, cement, is able to meet the demands of an ever increasing technological world. The research was made so that the writer would develop as complete an understanding of the processes involved in the manufacture of cement as was possible during the time allotted for this research.

The Application Of Limit Analysis To Shell Structures Using Existing Finite Element Analysis Codes, George G. Myers

Retrospective Theses and Dissertations

A ramjet inlet duct structure has been designed using nonlinear structural analysis to allow local plastic deformations which result in structural weight reduction. To establish the feasibility of reduced shell thickness, the Lower-Bound Theorem of limit analysis has been applied using an existing finite element analysis computer code intended for elastic analysis. The results of the analysis were verified by structural testing. Predicted stresses and deflections showed good correlation with measured values up to the point of failure. This work was supported by the U.S. Air Force Aero Propulsion Laboratory, Wright-Patterson Air Force Base, Ohio, under Contract No. F33615-72-C-1366.

Design And Thermal Performance Testing Of A Heat Pipe Flat Plate Solar Collector, Dennis N. Greeley

Retrospective Theses and Dissertations

This thesis investigates the use of heat pipes for removing heat from flat plate solar collectors and transferring the energy to air in a space heating system. Heat pipes are passive devices which are very efficient at transporting heat energy. They operate using a closed evaporation-condensation cycle. This thesis presents the fundamentals of flat plate collectors, heat pipes, and a set of parameters for evaluating a heat pipe flat collector. Also included are the results of this project and the recommendations for improvements.

Using Ebers-Moll Equations To Evaluate The Nonlinear Distortion In Bipolar Transistor Amplifiers, Amanollah Khosrovi

Retrospective Theses and Dissertations

The Ebers-Moll model, which is applicable to static or quasi-static conditions, is used as a basis for developing a simple method for the evaluation of harmonic distortion generated in bipolar transistor amplifiers. The Ebers-Moll equations are transformed into the desired forms using a Maclaurin Series expansion. A computer program is written to provide numerical results of the method, and these prediction are compared to measured distortion values.

An Optimization Model For Modular Incineration And Transfer Station Location In Municipal Solid Waste Systems, Ali Sajjadian

Retrospective Theses and Dissertations

Facility location models presently available in solid waste management are reviewed. From these models, one is adapted and modified to optimally locate the modular incinerator plants and transfer stations in municipal solid waste systems. The criteria for optimization is developed in terms of minimum total costs of the system. The generation and composition of municipal solid waste at present, and projected estimates into the future, through the year 2000, are also presented. Recommendations are made for the use of modular incinerators and conservation of landfills and use of the optimization model for locating incinerator plants and transfer stations by the …

Simulation Of A Fiber-Optical Communication System, Patricia Kay Scheffel

Retrospective Theses and Dissertations

The feasibility of analyzing an optical communication system using standard electronic circuit analysis programs such as SCEPTRE and ASTAP is demonstrated in this thesis. The transmitter (laser and modulator) and receiver (detector and amplifier) are modelled using equivalent circuits for the various components. The transmission medium (optical fiber) is modelled using an impulse response function. Two fibers are investigated--a step-index fiber and a square-law (parabolic index) fiber.

The Design And Analysis Of A Rare Earth Iron Magnetostrictive Underwater Sound Transducer, Steven Wayne Meeks

Retrospective Theses and Dissertations

The design and analysis of a low-frequency, resonant, tonpilz type, rare earth iron underwater sound transducer using rods of Tb.27Dy.73Fe1.95 are described. An equivalent circuit is presented which predicts the performance of the transducer in the presence of eddy currents and demagnetization. The effect of eddy currents on the impedance of a rod is discussed. The predicted performance of a laminated transducer is compared with that of an unlaminated transducer. The performance of the rare earth iron transducer is compared with the performance of the same transducer with identical ceramic active elements. Data on transmitting current response, transmitting voltage response, …

A Solar Cooling System Model Formulation Using Trnsys, David E. Daniel

Retrospective Theses and Dissertations

An absorption principal cooling system, currently proposed for installation and evaluation at the Florida Solar Energy Center (FSEC), is described as a system and modeled through use of "A Transient Simulation Program (TRNSYS)" developed by the University of Wisconsin. The system model included the FSEC building with its heat gains and losses due to insolation and conduction. System element and cooling load parameters are estimated and the basis of estimation is included to help identify adjustments required to fit the model to the final system installation as new or more complete data becomes available. Deficiencies noted in the current TRNSYS …

Test 1235: Steiger Panther Iii St-310 Diesel, 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 1238: Steiger Couger Iii St-270 Diesel, 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 1243: Ford 9700 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 …

Test 1246: Steiger Bearcat Iii St-220 Diesel, 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 1250: Massey-Ferguson 255 Diesel 12-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 1257: International Hydro 186 Diesel Hydrostatic, 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 1258: Massey-Ferguson 2805 Diesel 24-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 1262: Allis-Chalmers 8550 Diesel, 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 1263: John Deere 4840 Diesel, 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 1265: John Deere 4440 Diesel, 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 …

Infiltration In Stormwater Detention/ Percolation Basin Design, Robert David Beaver

Retrospective Theses and Dissertations

Investigations of soil parameters, infiltration testing, and storm observations are used to determine the infiltration characteristics for three Central Florida stormwater holding basins. Basic soil parameters are investigated and a value for available soil water storage is computed from these data. In-situ permeability and infiltration tests are used to obtain field permeability and infiltration rates. Infiltration test results may be applied to infiltration theory. Data from infiltration tests may be verified using available soil water storage computed from soil parameters. The effect of soil cover conditions is noted and investigated using the drum infiltrometer. Storm observations are used to confirm …

A Liquid Crystal Light Valve Used In A Remote Sensor, William Alexander Kownacki

Retrospective Theses and Dissertations

A nematic liquid crystal cell is used in conjunction with a mirror retro-reflector to modulate a low-power laser beam. The object is to determine the feasibility of the combination in transmitting information from a remote sensor without a large energy source at that sensor. Analog modulation does not appear workable, but a digitally-encoded scheme is feasible.

Hardware And Software Considerations For Improving The Throughput Of Scientific Computation Computers, Glenn Allen Sullivan

Retrospective Theses and Dissertations

In this paper, hardware and software techniques are presented for improving the Throughput (defined as computations per dollar) of computing systems which are oriented towards high-precision floating point computations. The various improvements are referenced to a baseline of the PDP 11/20, the NOVA 1200, and the TI 960A, all 16 bit minicomputers. The most beneficial hardware improvement is the inclusion of a Floating Point Processor, which yields up to 200X Throughput increase over a software floating point package. The inclusion of a cache high speed local memory and the availability of Polish Notation format instructions are shown to provide less …

Glass In The Year 2000, Norbert J. Kreidl

Materials Science and Engineering Faculty Research & Creative Works

No abstract provided.