Engineering Commons^™

Impact On Laminated Composite Materials, Serge Abrate

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Laminated composite materials are used extensively in aerospace and other applications. With their high specific modulus, high specific strength, and the capability of being tailored for a specific application, these materials offer definite advantages compared to more traditional materials. However, their behavior under impact is a concern, since impacts do occur during manufacture, normal operations, or maintenance. The situation is critical for impacts which induce significant internal damage, undetectable by visual inspection, that cause large drops in the strength and stability of the structure. Impact dynamics, including the motion of both the impactor and the target and the force developed …

Matrix Cracking In Laminated Composites: A Review, Serge Abrate

Mechanical and Aerospace Engineering Faculty Research & Creative Works

This article presents an overview of the problem of matrix cracking in laminated composite materials. The parameters governing the onset and accumulation of internal damage under several types of loadings are reviewed. The analysis of laminates with matrix cracks can be performed using a shear-lag model, variational, elasticity, finite element or finite difference approaches. Prediction of further cracking is based on either a fracture mechanics approach or a probabilistic failure strength theory. Continuum damage mechanics are used by some investigators to model the behavior of the cracked laminate. Recent developments in this area are summarized here, and suggestions for future …

Hierarchical Neurocontroller Architecture For Intelligent Robotic Manipulation, Xavier J. R. Avula, Luis C. Rabelo

Mechanical and Aerospace Engineering Faculty Research & Creative Works

A hierarchical neurocontroller architecture consisting of two artificial neural network systems for the manipulation of a robotic arm is presented. The higher-level neural system participates in the delineation of the robot arm workspace and coordinates transformation and the motion decision-making process. The lower one provides the correct sequence of control actions. The capabilities, including speed, adaptability, and computational efficiency, of the developed architecture are illustrated by an example.

Petri Net Modeling Of A Flexible Assembly Station For Printed Circuit Boards, M. Zhou, Ming-Chuan Leu

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Petri net modeling approaches are presented for a flexible workstation for automatic assembly of printed circuit boards. In order to improve the productivity of such a system, the building of mathematical models is a crucial step. Concentrating on the operational aspects, the authors construct ordinary and temporal Petri net models for the AT&T FWS-200 physical flexible workstation. Three outcomes follow from such models. First, designers can have a better understanding of concurrency, synchronization, mutual exclusion, and sequential relations involved in the system control from the graphical representations of Petri nets. Second, the performance analysis of system operations under different settings …

Test 1651: Case International 9250 Diesel And Steiger 9250 Diesel 12-Speeds, 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 1643: Ford 3430 (8x2) Diesel 8-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 1650: Case International 9240 Diesel And Steiger 9240 Diesel 12-Speeds, 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 Commodity Trading Model Based On A Neural Network-Expert System Hybrid, K. Bergerson, Donald C. Wunsch

Electrical and Computer Engineering Faculty Research & Creative Works

Demonstrates a system that combines a neural network approach with an expert system to provide superior performance compared to either approach alone. Learning capability is provided in a software-based approach to commodity trading systems. The authors used the backpropagation network with some parameters selected experimentally. They used a human expert to implicitly define patterns, using hindsight, that an intelligent system might have been able to use for an accurate prediction. Desired outputs were found by a combination of observing the behavior of technical indices that normally precede a certain kind of market behavior, and by observing the actual market behavior …

A Hybrid Optoelectronic Art-1 Neural Processor, Donald C. Wunsch, T. P. Caudell

Electrical and Computer Engineering Faculty Research & Creative Works

Summary form only given. A new implementation of ART-1 (adaptive resonance theory) has been proposed that efficiently combines optical and electronic devices. All parallel computations are performed by the optics, while serial operations are performed in electronics.

A Laboratory Investigation Of Electro-Optic Kerr Effect For Detection Of Electric Transmission Line Faults, Badrul H. Chowdhury, E. Grigsby, T. J. Englert

Electrical and Computer Engineering Faculty Research & Creative Works

A prototype Kerr cell has been constructed and tested for detecting and identifying faults by monitoring high voltages such as are found in electric power delivery systems. Simulated faults were generated under laboratory conditions and monitored by the Kerr cell. Preliminary analysis was done using analog-to-digital conversion of the detected waveforms with a single board microprocessor serially interfaced with a personal computer. The occurrence of faults is readily observed and results indicate that identification of fault types can be accomplished within less than one cycle of a standard sixty-cycle-per-second delivery system. With a dedicated analysis system such a technique may …

A Neural Architecture For Unsupervised Learning With Shift, Scale And Rotation Invariance, Efficient Software Simulation Heuristics, And Optoelectronic Implementation, Donald C. Wunsch, D. S. Newman, T. P. Caudell, R. A. Falk, C. David Capps

Electrical and Computer Engineering Faculty Research & Creative Works

A simple modification of the adaptive resonance theory (ART) neural network allows shift, scale and rotation invariant learning. The authors point out that this can be accomplished as a neural architecture by modifying the standard ART with hardwired interconnects that perform a Fourier-Mellin transform, and show how to modify the heuristics for efficient simulation of ART architectures to accomplish the additional innovation. Finally, they discuss the implementation of this in optoelectronic hardware, using a modification of the Van der Lugt optical correlator

Security Assessment Using Neural Computing, Badrul H. Chowdhury, B. M. Wilamowski

Electrical and Computer Engineering Faculty Research & Creative Works

The advantage of fast computation capability of an artificial neural network (ANN) is used to introduce an iterative scheme for security assessment of power systems. Two related approaches are shown which demonstratedly work satisfactorily. The idea of feedback in a single-layer feedforward neural network is experimented yielding higher accuracy. The ANN is trained by using a set of data obtained from off-line analysis of the power network. After training, an approximate solution for a given condition may be found almost immediately. The approximate solution obtained is judged adequate for assessing the security of the power system. A case study is …

Driving Of Thin Shells For Steel Encased Concrete Piles, G. Agrawal, Jean-Lou Chameau

JTRP Technical Reports

The major purpose of this study was to identify the causes for the driving difficulties often given experienced on highway projects where thin shells are used for cast-in situ concrete piles that support bridge approaches, and to develop a set of recommendations and procedures to enable INDOT engineers to (a) make use of available technology for dynamic analysis of pile driving; and (b) make appropriate changes in the design, construction and contract specification procedures to improve identification and correction of problems at the earliest possible stage.

This study indicates that the parameter of greatest importance for most projects is the …

A Mathematical Model Of A Sealed Nickel-Cadmium Battery, Deyuan Fan, Ralph E. White

Faculty Publications

A mathematical model for the charge and discharge of a sealed nickel-cadmium (Ni-Cd) battery is presented. The model is used to study the effect of transport properties of the electrolyte and kinetic parameters of the electrode reactions on the cell performance during the charge and discharge period. The model can also be used to demonstrate the changes of cell performance during cycling. Some comparisons between model predictions and experimental results indicate that the model predictions appear to fit the experimental data well. Sensitivity analyses illustrate that the sealed nickel-cadmium battery operates under activation control. It is also shown theoretically that …

Electrode Kinetics Of Oxygen Reduction In Lithium Carbonate Melt: Use Of Impedance Analysis And Cyclic Voltammetric Techniques To Determine The Effects Of Partial Pressure Of Oxygen, Bhasker B. Davé, Ralph E. White, Supramanian Srinivasan, A. John Appleby

Faculty Publications

The effects of the partial pressure of oxygen and temperature on the oxygen reduction on a submerged gold electrode in a lithium carbonate melt were investigated using cyclic voltammetry and impedance analysis. The values for the mass-transfer parameters, DC_O, obtained from cyclic voltammetry and impedance analysis were in good agreement. The reaction orders for oxygen at 800°C were calculated to be about 0.3 for the exchange current density and 0.5 for the product DC_O; these values are consistent with the mechanism proposed in the literature for oxygen reduction in Li₂CO₃ melt.

Modification Of Newman's Band(J) Subroutine To Multi-Region Systems Containing Interior Boundaries: Mband, D. Fan, Ralph E. White

Faculty Publications

Newman's BAND(J) subroutine, which has been used widely to solve models of various electrochemical systems, is extended to solve a system of coupled, ordinary differential equations with interior boundary conditions. A set of coupled, linear ordinary differential equations is used to demonstrate the solution procedure. The results show that the extended technique has the same accuracy as that of using pentadiagonal BAND(J), but the execution speed is about five times faster than that of pentadiagonal BAND(J). Using sparse matrix solver Y12MAF to solve the same set of equations takes even longer time than pentadiagonal BAND(J).

Precipitation, Inter-Event Dry Periods, And Reuse Design Curves For Selected Areas Of Florida, Martin Wanielista

BMP Trains Research and Publications

No abstract provided.

Test 1338/2: Hurlimann 6135 Vdt Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.

Nebraska Summary: S100 John Deere 3055, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data. EXPLANATION OF THE TEST PROCEDURES Purpose The purpose of …

Test 1652: Case International 9260 Diesel And Steiger 9260 Diesel 12-Speeds, 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 1654: Caterpiller Challenger 75 And 75c Diesel 10-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 1644: Ford 3930 (8x2) Diesel 8-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 1645: Ford 4630 (8x2) Diesel 8-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 1647: Ford 8730 Powershift 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 …

Test 1649: Case International 9230 And Steiger 9230 (12-Speeds) Diesels, 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 Technological Development Model For Strategy Formation, Halvard E. Nystrom

Engineering Management and Systems Engineering Faculty Research & Creative Works

Summary form only given, as follows. The author presents a technological development model for product and company development based on a distinction between explicit and implicit technologies. Implicit technologies are evolving technologies while explicit technologies are established technologies. Based on empirical data from Swedish companies, a number of strategic dimensions are discussed such as network interaction and combining knowledge from various sources. These concepts are then used to present an integrated model of strategy formation and product and company development. It is argued that this view of technological development facilitates the understanding and analysis of innovation and entrepreneurship in highly …

Error Control Coding For Meteor Burst Communications, Thomas J. Frederick

Retrospective Theses and Dissertations

The phenomenon of meteor burst communications is described and its mathematical model is presented. Protocols for meteors burst systems are outlined and examples are given of current use. Recent research in the area of coding performance in meteor burst systems is pointed out. The performance of several error control coding schemes for a meteor burst channel, including two new adaptive algorithms, are evaluated via analysis and simulation. These coding strategies are compared using the probability of successful transmission of a fixed size packet through a single burst as a performance measure. The coding methods are compared via simulation for several …

Itasq : An Ada-Based Interactive Tool For Assessing Software Quality, Ruby Marie Heintze

Retrospective Theses and Dissertations

The goal of producing high quality computer programs brings with it the need for a set of quantitative measures that software engineers can use to measure various aspects of software quality. These quantitative measures, known as software metrics, can measure different aspects of program quality. For example, McCabe's Complexity Metric measures the decision structure of a computer program; Halstead's Software Science measures program "impurities II such as unfactored expressions and unnecessary replacements; and Vitro•s Module Coupling Metric measures data transfer characteristics between modules. Using only one of these metrics would not provide a well rounded measure of overall software quality. …

Surface Acoustic Wave Resonator Parameter Extraction And Oscillator Design, Mark Stephen Cavin

Retrospective Theses and Dissertations

Surface Acoustic Wave (SAW) resonators are frequently used in UHF oscillator designs. SAW resonators are available in the 100 MHz - 1 GHz frequency range which eliminates the need for frequency multiplication necessary with Bulk Acoustic Wave (BAW) devices. As operating frequencies increase, circuit parasitics play a larger role in device performance. One important source of parasitics is the device package and associated interconnects. To model a SAW resonator effectively, these parasitics need to be taken into account Resonator device models and their associated S-parameters can then be used in the design of oscillators. This thesis will discuss the design …

A Corrected Mixture Law For B/A, E. Carr Everbach, Z. Zhu, P. Jiang, B. T. Chu, R. E. Apfel

Engineering Faculty Works

A derivation is presented that corrects an expression for the effective acoustic nonlinearity parameter of a mixture of immiscible liquids. The derivation is based upon a mass fraction, rather than volume fraction, formulation.