Engineering Commons^™

Neural Network Enhancement Of The Los Alamos Force Deployment Estimator, Bobby Turner, Donald C. Wunsch

Electrical and Computer Engineering Faculty Research & Creative Works

The Force Deployment Estimator (FDE) is a decision support system. It allocates transportation resources given inputs such as forces to be deployed and their desired arrival times. Other inputs are assumptions about conditions that affect performance: carrier start time, node capacity, sustainment shipping time, bulk sustainment per day, ammo sustainment per day, unit start time, carrier service time, carrier round trip time, and carrier reassignment time. Outputs include the mean and standard deviation of estimated unit arrival times versus goal times, and data files for post-processing. However, when a goal time is not met, the simulator gives no explanation of …

On Fault Modeling And Testing Of Content-Addressable Memories, Waleed K. Al-Assadi, A. P. Jayasumana, Y. K. Malaiya

Electrical and Computer Engineering Faculty Research & Creative Works

Associative or content addressable memories can be used for many computing applications. This paper discusses fault modeling for the content addressable memory (CAM) chips. Detailed examination of a single CAM cell is presented. A functional fault model for a CAM architecture executing exact match derived from the single cell model is presented. An efficient testing strategy can be derived using the proposed fault model

A Stochastic One-Dimensional Image Model Based On Occluding Object Images, John A. Stuller

Electrical and Computer Engineering Faculty Research & Creative Works

This Paper Provides New Insights into the Formation of One-Dimensional (Line-Scan) Image Autocorrelation Functions. We Model a Line Scan as a Composition of Individual Object-Images that Have Random Positions, Widths and Intensities and that Occlude One Another. We Derive the Autocorrelation Function of This Model as a Function of Object-Image Width and Intensity Distributions. We Show that Any Assumption Regarding the Form of the Autocorrelation Function Places a Constraint on Object-Image Width and Intensity Distributions and We Derive the Object-Image Width Distribution Associated with the Widely Used Symmetric-Exponential Autocovariance Model.

Buckling Of A Coating Bonded To A Round Bar Subjected To Axial Extension. Mech. Mater. 15 (1993) 131-138, C. W. Bert, Victor Birman

Mechanical and Aerospace Engineering Faculty Research & Creative Works

No abstract provided.

On The Propagation Of A Shear Band In A Steel Tube, R. C. Batra, Xiangtong Zhang

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Marchand and Duffy tested thin-walled steel tubes in a split Hopkinson torsion bar at a nominal strain-rate of approximately 1600/s and could not determine conclusively whether a shear band initiating at a point in the tube propagated around the circumference in one direction or in both directions. They estimated the speed of propagation to be 520 m/s in the former case and 260 m/s in the latter. Here we simulate their test numerically and find that the shear band propagates in both directions around the circumference of the tube. When the tube is twisted at a nominal strain-rate of 5000/s, …

Estimation Of Resilient Modulus Of Fine-Grained Subgrade Soils, David Newton Richardson

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

No abstract provided.

The Adaptive Control Of Smart Structures Using Neural Networks, Vittal Rao, Rajendra Damle, Chris Tebbe, Frank J. Kern

Electrical and Computer Engineering Faculty Research & Creative Works

The application of adaptive control algorithms for vibration suppression of smart structures is investigated in this paper. An accurate mathematical representation is not required in this approach. The controller adapts to the parameter variations of the structural system by updating the controller gains. When the desired performance of an unknown plant with respect to an input signal can be specified in the form of a linear or a non-linear differential equation, stable control can be achieved using model-reference adaptive control (MRAC) techniques. The conventional MRAC techniques have been successfully implemented on a smart-structure test article resulting in perfect model following. …

Experiences In The Integration Of Design Across The Mechanical Engineering Curriculum, Ashok Midha, J. M. Starkey, D. P. Dewitt, R. W. Fox

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The Faculty of the School of Mechanical Engineering at Purdue University have effected a major change in the Purdue Mechanical Engineering program by integrating design throughout the curriculum. In doing so, a significant level of faculty interaction has been achieved as well. The goals of the curriculum revision are: (1) to improve student skills in how to solve open-ended design problems, (2) to reduce the core of the curriculum to allow flexibility in course selection, and allow time for solving design problems, (3) to improve student skills in team work and communications, and (4) to improve student skills in using …

A Study Of The Sintering Mechanism Of Pzt-Based Piezoceramics, Wayne Huebner, Pei Wen Lu, Wanrong Xue

Materials Science and Engineering Faculty Research & Creative Works

The densification behavior a PZT-based composition with additions of BiFeO3 as a flux was studied. Two different PZT powders were studied with varying initial particle sizes. Results clearly showed that BiFeO3 forms a low temperature liquid that aids in the densification behavior, with 3 mole% being optimum. Fine particle sizes substantially improved the density at low temperatures, with the net result that ceramics could be densified in air without the aid of a lead source. The corresponding electromechanical properties were typical of a hard PZT formulation.

Correlation Of Wettability And Interfacial Reaction To The Densification And Dielectric Properties Of Fluxed-Batio₃, Sea-Fue Wang, Wayne Huebner, Joseph P. Dougherty

Materials Science and Engineering Faculty Research & Creative Works

Reducing the sintering temperature of BaTiO3 has typically been achieved through the use of a fluxing agent to promote densification by liquid phase sintering. Liquid phase formation in these systems is due either to the melting of the flux or to the formation of a eutectic liquid between the flux and BaTiO3. In this paper, the correlation between the wettability and interfacial reactions between fluxes and BaTiO3 with respect to the densification behavior associated with liquid phase sintering, and the resulting dielectric properties is presented. Fluxes used in this study include 5ZnO*2B2O3, 5CdO*2SiO2, Pb5Ge3O11, CuO*TiO2, 3Bi2O3*B2O3, and LiF.

Fabrication Of 2-2 Connectivity Pzt/Thermoplastic Composites For High Frequency Linear Arrays, Wayne Huebner, Mary R. Reidmeyer, L. Busse, Jeffry W. Stevenson

Materials Science and Engineering Faculty Research & Creative Works

An alternate approach for fabricating PZT/polymer composites with 2-2 connectivity with fine scales is described. Thin (less than or equal to 20 micrometers) sintered PZT plates and sheets of a thermoplastic polymer film (less than or equal to 10 micrometers) were bonded together via thermal processing. Stack sintering of tape cast PZT generated the necessary PZT plates, while tape cast polymers were used to control the thermoplastic thickness. Composite blocks were cut to required dimensions for linear arrays, electroded, and poled. Electromechanical properties were measured to evaluate the composites. The significance of this fabrication technique is that it is able …

The Role Of Component Packaging In System Electromagnetic Compatibility, Todd H. Hubing

Electrical and Computer Engineering Faculty Research & Creative Works

Increases in the speed and density of electronic systems do not necessarily result in tougher electromagnetic compatibility problems. In fact, recent advances in packaging technology can help designers to meet electromagnetic compatibility requirements. However, working with new technologies requires us to re-evaluate existing EMC design models and guidelines. Understanding the system-level impact of component-level packaging changes, is a prerequisite for meeting stringent electromagnetic compatibility requirements in a timely and cost-effective manner.

Positron Annihilation Determination Of Damage Caused By Fatigue Cycling In The Superalloy Haynes 188, D. Hoeckelman, Hollis P. Leighly

Materials Science and Engineering Faculty Research & Creative Works

No abstract provided.

Density Changes During Isothermal Annealing Of A Quenched Pb–7.45 At% Sn Alloy, Hollis P. Leighly, A. Belaidi

Materials Science and Engineering Faculty Research & Creative Works

The increase in density of a Pb–7.45 at% Sn alloy annealed at 150, 165, 180, and 195 °C and quenched at 20, 21.5, 23, 25, and 30 °C is measured isothermally. This increase in density accompanies the formation of the Sn‐rich phase precipitating as a function of time at the quenching temperature. The quenching is rapid enough to retain some vacancies at equilibrium at the annealing temperature. These vacancies accelerate the early stages of precipitation. The change in density versus time obeys the kinetic law allowing the determination of the reaction rate constant for several annealing and quenching conditions. Copyright …

Liquid-Mix Synthesis Of Oxide Powders And Thin Films Using A Starch-Based Polymer, Lone Wen F. Tai, Harlan U. Anderson

Materials Science and Engineering Faculty Research & Creative Works

A commercially available water-soluble starch derivative was used as the sole organic precursor in the Liquid-Mix synthesis of mixed-cation oxide powders and thin films. The acidified polymer (by nitric acid) was able to complex metal ions through the carboxylate ligands. Loosely agglomerated fine powders as well as dense thin films of complex oxides have been prepared using the same type of polymer. Oxide powders of Cr-doped lanthanum aluminate and yttrium aluminum garnet both crystallized in a single step, without forming any intermediate or second phases, when the amorphous resin intermediates were calcined at 650 °C and 750 °C for 2 …

Multiphase Equilibrium Behavior Of The Mixture Carbon Dioxide + Ethane + Methanol, Seung Pyo Hong, Christi L. Patton (Luks), Kraemer D. Luke

Chemical and Biochemical Engineering Faculty Research & Creative Works

The Three-Phase Liquid-Liquid-Vapor (Llg) Phase Equilibrium Behavior of the Mixture Carbon Dioxide + Ethane + Methanol Was Experimentally Studied. the Boundaries of the Three-Phase Llg Region in Pressure-Temperature Space Are Delineated. Compositions and Molar Volumes of the Two Liquid Phases and the Vapor Phase Along the 288.15 and 298.15 K Isotherms Are Reported. © 1994, American Chemical Society. All Rights Reserved.

Data-Feedthrough Faults In Circuits Using Unclocked Storage Elements, Waleed K. Al-Assadi, D. Lu, A. P. Jayasumana, Y. K. Malaiya, C. Q. Tong

Electrical and Computer Engineering Faculty Research & Creative Works

Some faults in storage elements (SEs) do not manifest as stuck-at-0/1 faults. These include data-feedthrough faults that cause the SE cell to exhibit combinational behaviour. The authors investigate the implications of such faults on the behaviour of circuits using unclocked SEs. It is shown that effects of data-feedthrough faults at the behavioural level are different from those due to stuck-at faults, and therefore tests generated for the latter may be inadequate

A Comparison Of Fam And Cmac For Nonlinear Control, Arit Thammano, Cihan H. Dagli

Engineering Management and Systems Engineering Faculty Research & Creative Works

This article compares a neural network-based controller, both local and global networks, with fuzzy associative memories (FAM) on a nonlinear problem. CMAC and FAM are chosen as representatives of local generalization networks. CMAC controller is trained off-line, therefore, it can response to the incoming input immediately. CMAC can interpolate its memory and give a reasonable control signal even the input has not been trained on. Backpropagation is picked as a representative of global generalization networks. All three systems are studied on a simple simulated control problem. This preliminary research will be adapted later to control the laser cutting machine. A …

The Integration Of Simulation And Reality For Education Enhancement And Training, Clarence Rasquinha, Stephen A. Raper

Engineering Management and Systems Engineering Faculty Research & Creative Works

Quite often, when engineers are exposed to a manufacturing environment on the job for the first time, they undergo a baptism by fire. The environment forces them to deal with situations that integrate many different bodies of knowledge. Reliance on concepts acquired in the academic environment is crucial to their success. Unfortunately, lacking in most academic environments, is any experience through which some or all of these concepts are integrated. In a continuing effort to enhance educational practices in Manufucturing/Systems Engineering programs and perhaps improve the preparedness of a young engineer, the CITE (Computer Integrated Technological Enterprise) tool offers educators …

Ai-Based Generation Of Production Engineering Labor Standards, Hulya Yazici, Colin Othniel Benjamin, James Mcglaughlin

Engineering Management and Systems Engineering Faculty Research & Creative Works

Increased automation of manufacturing is necessary to compete in today's worldwide markets. The role of artificial intelligence (AI) techniques for incorporating the automation with changing manufacturing environments needs to be investigated. Al techniques can assist in meeting the challenge of transforming shop floor production engineering data into appropriate production engineering labor standards in a timely, consistent, and cost-effective manner. Production heuristics can be incorporated into an expert system that can learn from the changing manufacturing environment. This paper presents a prototype expert system which transfers the knowledge of experienced methods engineers into a rule-based system to develop the appropriate job …

Synthesis And Characterization Of Ysz Thin Film Electrolytes, C. C. Chen, M. M. Nasrallah, Harlan U. Anderson

Materials Science and Engineering Faculty Research & Creative Works

Dense, homogeneous and crack-free thin films (0.2-2 microm in thickness) of (ZrO2)0.84(YO1.5)0.16 (YSZ) were deposited on porous or dense substrates, at temperatures not exceeding 600°C, using a solution-deposition technique. The structural evolution and microstructure of the deposited films were investigated using X-ray diffraction (XRD) and scanning electron microscopy (SEM). Raman spectroscopy revealed the presence of fine-grain cubic YSZ at annealing temperatures as low as 600°C. Grain growth occurred at higher temperatures as detected by atomic force microscopy (AFM). ac impedance spectroscopy was used to study the electrical characteristics of the YSZ films as a function of temperature. The ionic conductivity …

A Hierarchial Neural Network Implementation For Forecasting, B. Fulkerson, M. A. Ozbayoglu, Cihan H. Dagli

Engineering Management and Systems Engineering Faculty Research & Creative Works

In this paper, a hierarchical neural network architecture for forecasting time series is presented. The architecture is composed of two hierarchical levels using a maximum likelihood competitive learning algorithm. The first level of the system has three experts each using backpropagation and a gating network to partition the input space in order to map the input vectors to the output vectors. The second level of the hierarchical network has an expert using fuzzy ART for producing the correct trend coming from the first level. The experiments show that the resulting network is capable of forecasting the changes in the input …

Optimal Control Of Infinite-Order Smart Composite Structural Systems Using Distributed Sensors, Robert Butler, Vittal S. Rao

Electrical and Computer Engineering Faculty Research & Creative Works

In recent years there has been considerable interest in the design of spatially shaped distributed sensors for the control of infinite-order structural systems. The smart materials polyvinylidene fluoride (PVDF) and shape-memory alloys can be utilized in the development of customized distributed sensors. Sensor shape-optimization techniques are needed for the implementation of optimal control strategies. In this paper, a method for generating the shapes of distributed sensors using finite-dimensional approximations to desired curvature and curvature rate kernels is examined. The output of these spatially distributed sensors is utilized directly as the control signal for suppressing vibrations in infinite-order structural systems. This …

Order-Recursive Fir Smoothers, Jenq Tay Yuan, John A. Stuller

Electrical and Computer Engineering Faculty Research & Creative Works

This Paper Introduces Order-Recursive FIR Smoothers and Shows that Order-Recursive FIR Filters Are Special Forms that Occur When No Future Data Values Are Used to Estimate the Signal. the Formulation Leads Naturally to Generalizations of the Concepts of Prediction-Error Basis and Cholesky Factorization Which Are Well Known in FIR Filter Design. © 1994 IEEE

Impact On Laminated Composites: Recent Advances, Serge Abrate

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Impact damage in structures made out of composite materials is a major concern since such damage can be introduced during the life of the structure, and its mechanical properties can be drastically reduced as a result. In a previous review of the literature on impact on composite materials, this author considered 285 published before 1989. In this article over 300 articles most of which appeared after 1989 are reviewed. These figures indicate that this is a very active area of research, and the present paper seeks to present a comprehensive view of the latest developments. Taken together, these two reviews …

On The Interface Stability Of A Neck Propagating In A Sheet Reinforced With Shape-Memory Fibers, C. Q. Ru, R. C. Batra

Mechanical and Aerospace Engineering Faculty Research & Creative Works

We propose a simple model of necking in a sheet reinforced with straight fibers made of a shape-memory alloy and examine conditions under which the interface between the necked and the unnecked region is morphologically stable. We use the Mullins and Sekerka (1963, J. Appl. Phys. 34, 323-330; 1964, J. Appl. Phys. 35, 444-450) method, established for studying the stability of a moving interface in a solidification problem, to investigate the interface stability of a propagating neck. It is found that the moving straight interface is morphologically stable for several typical cases even in the absence of surface-tension effects, and …

The Application Of Markov State Probabilities In Developing Artificially Intelligent Managerial Strategies: A Case Study Based On Major League Baseball, Arnold Vincent Arconati

Doctoral Dissertations

"Baseball is a very large industry that influences the lives and financial assets of millions of people.

Many baseball analysts estimate that even the best Major League player can increase his team's expected number of yearly wins by only 3 or 4 games. In 1993 Bobby Bonilla, a New York Mets National League outfielder, earned $5,200,000 more than the average Major League player earned. The Mets apparently believed that expenditure of this money was worth his expected additional victories. If the strategy of an Artificially Intelligent baseball manager could produce 4 more team victories than the corresponding human baseball manager, …

Final State Distributions For Electron Capture From Orientated Rydberg Atoms, Jee-Ching Wang, Ronald E. Olson

Chemical and Biochemical Engineering Faculty Research & Creative Works

Final state nim distributions are studied for electron capture from orientated circular Rydberg atoms. Strong orientation effects are found for all quantum numbers at collision speeds comparable to the electron orbital speed. Predominant population of large m states is observed when the plane of the circular orbit is nearly perpendicular to the incident direction of the projectile. The Ini distributions show structures due to quasi-Thomas scattering even at low relative collision velocities. © 1993 IOP Publishing Ltd.

Ionic Charge Dependence Of The Zero Degree Binary Encounter Peak For Partially Stripped Heavy Ions, W. Wolff, H. E. Wolff, J. L. Shinpaugh, Jee-Ching Wang, Ronald E. Olson, D. Fainstein, S. Lencinas, U. Bechthold, R. Herrmann, H. Schmidt-Bocking

Chemical and Biochemical Engineering Faculty Research & Creative Works

We report on the measurements of double differential cross sections, at zero degree, for the production of secondary electrons from the collision of 0, 6 MeV amu^-1 Cu⁵⁺, I⁷⁺, Au¹¹⁺, U¹³⁺, Cu¹⁹⁺, t²³⁺ and Au²⁹⁺ projectiles with H₂ and He. The shapes and positions of the observed binary encounter electron peaks are compared with continuum distorted wave-eikonal initial state (CDW-EIS), impulse approximation and classical trajectory Monte Carlo calculations, as well as with predictions from an adiabatic resonant tunnelling model recently proposed by Fainstein and co-workers. The …

Periodic Pn Sequence Delay Estimation Using Phase Spectrum Data, Kurt Louis Kosbar, Jorge J. Zaninovich

Electrical and Computer Engineering Faculty Research & Creative Works

An algorithm for estimating the delay of a periodic pseudonoise (PN) sequence is presented. It is a rapid, block-based estimator that can be used for both linear and nonlinear codes. The algorithm exploits the periodicity of the difference between the phase spectra of the received sequence and a local reference. The estimator takes the Fourier transform of the phase spectrum difference data, and searches for the fundamental frequency. Unlike previously described methods, phase unwrapping is not required. The performance in the presence of additive white Gaussian noise (AWGN) and a continuous wave (CW) jammer is investigated using computer simulation. Comparisons …