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Articles 15871 - 15900 of 21740

Full-Text Articles in Engineering

Consideration Of Phase Transformations In The Study Of Shear Bands In A Dynamically Loaded Steel Block, Z. G. Zhu, R. C. Batra Jan 1992

Consideration Of Phase Transformations In The Study Of Shear Bands In A Dynamically Loaded Steel Block, Z. G. Zhu, R. C. Batra

Mechanical and Aerospace Engineering Faculty Research & Creative Works

We study plane strain thermomechanical deformations of a square block made of steel and model a material defect in it by a rigid non-heat-conducting ellipsoidal inclusion located at the center of the block. The boundaries of the block are presumed to be thermally insulated, and its top and bottom surfaces compressed vertically at a prescribed rate. The loading pulse is assumed to be made up of three parts; an initial segment in which the speed increases from zero to the steady value, the steady part, and the third part in which the speed decreases gradually to zero and is maintained …

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Fast Power Flow With Capability Of Corrective Control Using A Neural Network, Badrul H. Chowdhury, B. M. Wilamowski Jan 1992

Fast Power Flow With Capability Of Corrective Control Using A Neural Network, Badrul H. Chowdhury, B. M. Wilamowski

Electrical and Computer Engineering Faculty Research & Creative Works

The authors present a number of different configurations of a neural network and identify a particular case which is most suitable for power flow analysis in real-time applications. The advantage of fast computation of the artificial neural network (ANN) is used for obtaining power flow solutions in real time. The inputs to the ANN are the real and reactive power generating and demand in the system, and the output data are the complex bus voltages. A few configurations of the neural network were experimented with, and the best results were achieved with a single-layer feedforward neural network with nonlinear feedback. …

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New Emc Design Guidelines For Multilayer Printed Wiring Boards, Todd H. Hubing, Thomas Van Doren Jan 1992

New Emc Design Guidelines For Multilayer Printed Wiring Boards, Todd H. Hubing, Thomas Van Doren

Electrical and Computer Engineering Faculty Research & Creative Works

No abstract provided.

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Optimizing The Integration Of Photovoltaic Systems With Electric Utilities, Badrul H. Chowdhury Jan 1992

Optimizing The Integration Of Photovoltaic Systems With Electric Utilities, Badrul H. Chowdhury

Electrical and Computer Engineering Faculty Research & Creative Works

The author introduces a comprehensive simulation package whereby the optimal size, operation, performance and economics of a photovoltaic (PV) system can be determined in the utility-integrated mode. The central issue is to present a single definitive optimization model. A stepwise analytical methodology starting at the solar resource and culminating in the value of the PV system in terms of avoided costs is provided. The methodology includes processing of the solar irradiance; identification of the PV system''s configuration and operational features; identification of real-time system controls in the presence of PV generation; security assessment in the presence of PV and production …

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An Optical Adaptive Resonance Neural Network Utilizing Phase Conjugation, Donald C. Wunsch, D. J. Morris, T. P. Caudell, R. A. Falk Jan 1992

An Optical Adaptive Resonance Neural Network Utilizing Phase Conjugation, Donald C. Wunsch, D. J. Morris, T. P. Caudell, R. A. Falk

Electrical and Computer Engineering Faculty Research & Creative Works

An adaptive resonance (ART) device has been conceived that is fully optical in the input-output processing path. It is based on holographic information processing in a phase-conjugating crystal. This sets up an associative pattern retrieval in a resonating loop utilizing angle-multiplexed reference beams for pattern classification. A reset mechanism is used to reject any given beam, allowing an ART search strategy. The design is similar to an existing nonlearning optical associative memory, but it does allow learning and makes use of information the other device discards. This device is expected to offer higher information storage density than alternative ART implementations.

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X‐Ray Powder Diffraction Structural Phase‐Transition Study Of La(Cr1‐Xmnx)O3 (X = 0 To 0.25) Using The Rietveld Method Of Analysis, Scott A. Howard, Jen‐Kuan ‐K Yau, Harlan U. Anderson Jan 1992

X‐Ray Powder Diffraction Structural Phase‐Transition Study Of La(Cr1‐Xmnx)O3 (X = 0 To 0.25) Using The Rietveld Method Of Analysis, Scott A. Howard, Jen‐Kuan ‐K Yau, Harlan U. Anderson

Materials Science and Engineering Faculty Research & Creative Works

The La(Cr1‐xMnx)O3 (x = 0 to 0.25) system exhibited a displacive phase transformation from an orthorhombic to a rhombohedral structure at temperatures ranging from about 256°C at x= 0 to 305°C at x= 0.25. The Rietveld method of X‐ray analysis was used to determine structural characteristics and to assay phase concentrations when multiple phases were present. Indications were that the Mn ions on the B site affected the transition temperature through an ionic size effect; i.e., Mn3+, with a larger ionic size than Cr3+, increased the transition temperature while the presence …

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Mixed‐Cation Oxide Powders Via Resin Intermediates Derived From A Water‐Soluble Polymer, Lone‐Wen ‐W Tai, Harlan U. Anderson, Paul A. Lessing Jan 1992

Mixed‐Cation Oxide Powders Via Resin Intermediates Derived From A Water‐Soluble Polymer, Lone‐Wen ‐W Tai, Harlan U. Anderson, Paul A. Lessing

Materials Science and Engineering Faculty Research & Creative Works

Sub micrometer powders of complex oxides were prepared via resin intermediates based on a starch type of organic precursor. A commercially available water‐soluble starch derivative was (for the first time) used as the organic base for solution synthesis of ceramic powders. Calcination of the charred, fluffy, amorphous resins at a temperature below 600°C for 4 h yielded perovskite powders of Sr‐doped LaMnO3 and Sr‐doped La(Fe,Co)O3. Sr‐doped LaCrO3 needed to be calcined above 750°C to ensure phase purity and to remove organic residue. Due to the low cost of starch derivatives, the process has the potential of …

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Sme Annual Meeting. Phoenix, Usa. February 22-27, 1992, Johh L. Watson Jan 1992

Sme Annual Meeting. Phoenix, Usa. February 22-27, 1992, Johh L. Watson

Materials Science and Engineering Faculty Research & Creative Works

No abstract provided.

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Solvent Extraction Reagent Entrainment Effects On Zinc Electrowinning From Waste Oxide Leach Solutions, M. Neira, Thomas J. O'Keefe, Johh L. Watson Jan 1992

Solvent Extraction Reagent Entrainment Effects On Zinc Electrowinning From Waste Oxide Leach Solutions, M. Neira, Thomas J. O'Keefe, Johh L. Watson

Materials Science and Engineering Faculty Research & Creative Works

A considerable quantity of metal-containing waste oxide is generated by the primary metal industry, and under increased environmental regulation, treatment of these wastes has become viable. Hydrometallurgical processing is often appropriate and one potential treatment process for zinc oxide wastes involves leaching the oxide with an acid, purifying by a solvent extraction operation, and recovering metallic zinc by electrowinning the purified leach solution. The purification stage is frequently critical and the introduction of a solvent extraction organic reagent into the flowsheet can be detrimental to downstream processes. The object of this study was to determine the effect of organics, entrained …

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Review Of P-Type Doped Perovskite Materials For Sofc And Other Applications, Harlan U. Anderson Jan 1992

Review Of P-Type Doped Perovskite Materials For Sofc And Other Applications, Harlan U. Anderson

Materials Science and Engineering Faculty Research & Creative Works

p-type perovskite-type oxides are candidates for use as components of high temperature fuel cells and as oxygen separation membranes. The particular properties that these applications require are reviewed. The characteristics that these oxides have which allow them to satisfy many of these requirements are discussed and a defect model presented. The status of the utilization of these oxides and of the areas which need to be addressed such as thermal expansion and sintering characteristics are reviewed. © 1992.

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Tensile Fatigue Behaviour Of Tightly Woven Carbon/Carbon Composites, A. Ozturk, Robert E. Moore Jan 1992

Tensile Fatigue Behaviour Of Tightly Woven Carbon/Carbon Composites, A. Ozturk, Robert E. Moore

Materials Science and Engineering Faculty Research & Creative Works

The tensile fatigue behavior of a tightly woven carbon/carbon composite was investigated as a function of stress level. Load-controlled fatigue tests were performed in tension-tension mode with a stress ratio, R, of 0.1 under ambient laboratory conditions. Results of composite behavior are discussed in terms of the relationship of the stress/strain behavior to the fatigue life of these composites as well as the effects of applied stress levels. It is shown that these composites exhibit good resistance to cyclic loading. No fatigue failures were obtained after 106 cycles when the maximum tensile load in the fatigue cycle is less than …

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Electrical Conductivity And Seebeck Coefficient Of (La, Ca) (Cr, Co)O3, R. Koc, Harlan U. Anderson Jan 1992

Electrical Conductivity And Seebeck Coefficient Of (La, Ca) (Cr, Co)O3, R. Koc, Harlan U. Anderson

Materials Science and Engineering Faculty Research & Creative Works

Electrical conductivity and Seebeck coefficients of (La, Ca) (Cr, Co)O3 were measured as a function of temperature. The electrical conductivity as measured in air from 100 to 1100 °C increased with increasing Co and Ca content. The Seebeck coefficients were positive, indicating p-type conductivity. The substitution of Co for Cr significantly decreased the Seebeck coefficients, indicating that the substitution resulted in an increase in site occupancy, associated with the Co. The additional Ca substitution for La resulted in further decrease in the Seebeck coefficients, then exhibited a temperature-independent behaviour, indicating that the carrier mobility, rather than carrier concentration, was …

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Effect Of Cation Substitution On The Thermal Expansion Coefficient Of Lacro3, R. Koc, Harlan U. Anderson Jan 1992

Effect Of Cation Substitution On The Thermal Expansion Coefficient Of Lacro3, R. Koc, Harlan U. Anderson

Materials Science and Engineering Faculty Research & Creative Works

No abstract provided.

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Coperite-Computer-Aided Tool For Power Engineering Research, Instruction, Training And Education, Badrul H. Chowdhury, D. E. Clark Jan 1992

Coperite-Computer-Aided Tool For Power Engineering Research, Instruction, Training And Education, Badrul H. Chowdhury, D. E. Clark

Electrical and Computer Engineering Faculty Research & Creative Works

A graphics-oriented, primarily PC-based tool for education, research, and training in power engineering is introduced. The tool, called COPERITE, has all user interfaces resident on an IBM-386 microcomputer. Menus and windows are used for the interface, and attractive graphical representations and displays are included. Application programs that are interfaced are power flow, contingency analysis, economic dispatch, security-constrained dispatch, system stability, and fault analysis. These programs are executed on a VAX 8800 computer mainly for speed of execution. Information exchange between the PC and the VAX is made through an Ethernet connection which is transparent to the user. Results of execution …

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Machining Of Composite Materials. Part Ii: Non-Traditional Methods, Serge Abrate, D. Walton Jan 1992

Machining Of Composite Materials. Part Ii: Non-Traditional Methods, Serge Abrate, D. Walton

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Machining of composite materials is difficult due to the heterogeneity and heat sensitivity of the material and the high abrasiveness of the reinforcing fibers. This results in damage being introduced into the workpiece and very high tool wear. The use of traditional machining methods was reviewed in Part I of this paper. Here new methods are considered: laser, waterjet, electro-discharge, electro-chemical spark, and ultrasonic machining. These various techniques have been applied to organic matrix composites with aramid, glass, graphite fiber reinforcement but also to metal matrix and ceramic matrix composites. © 1992.

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Effect Of Temperature On The Ultimate Strength And Modulus Of Whisker‐Reinforced Ceramics, Douglas R. Carroll, Lokeswarappa R. Dharani Jan 1992

Effect Of Temperature On The Ultimate Strength And Modulus Of Whisker‐Reinforced Ceramics, Douglas R. Carroll, Lokeswarappa R. Dharani

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Whiskers are a very attractive means of reinforcing a ceramic material. It has been shown that the whiskers dramatically improve the ultimate strength and modulus of the materials at room temperature. However, recent studies indicate that at high temperatures the improvement is less pronounced, or there is no improvement at all. In this paper a model is developed to explain why the properties are degraded at high temperature. The parameters which seem most important for high‐temperature performance are the coefficients of thermal expansion and Poisson's ratios for the constituents, the heat treatment temperature, and the coefficient of friction between the …

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Object-Based Analog Vlsi Vision Circuits, C. Koch, B. Mathur, S. C. Liu, J. G. Harris, J. Luo, M. Sivilotti Jan 1992

Object-Based Analog Vlsi Vision Circuits, C. Koch, B. Mathur, S. C. Liu, J. G. Harris, J. Luo, M. Sivilotti

Electrical and Computer Engineering Faculty Research & Creative Works

Early vision algorithms typically can be classified as either pixel-based or image-based. Pixel-based algorithms such as edge detection and optical flow produce a dense output on every grid point. Image-level algorithms such as center of mass computation [1,5] produce a few outputs by integrating information from the entire image. Most special-purpose analog VLSI vision chips developed so far implement early vision algorithms of these categories. Little work has been done in building special-purpose chips that move beyond these early-vision algorithms. Dynamic wires, first introduced by Liu and Harris [2], provide an avenue for object-based processing. The dynamic wire model is …

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Effect Of Strain Rate On Material Properties Of Sheet Steels, M. Kassar, Wei-Wen Yu Jan 1992

Effect Of Strain Rate On Material Properties Of Sheet Steels, M. Kassar, Wei-Wen Yu

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The effect of strain rate on tensile and compressive mechanical properties of sheet steels is investigated experimentally and analytically. Three sheet steels are studied in both longitudinal and transverse directions under different strain rates and different amounts of prior cold stretching in order to determine the separate effects of strain rate and aging half of the cold-stretched coupons are tested in an average of two days after cold-stretching operation. The remaining half are tested to failure at least 30 days after cold-stretching operation The results show that the proportional limit yield strength and ultimate strength increase with increasing strain rate …

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Use Of Time Varying Dynamics In Neural Network To Solve Multi-Target Classification, S. N. Balakrishnan, J. Rainwater Jan 1992

Use Of Time Varying Dynamics In Neural Network To Solve Multi-Target Classification, S. N. Balakrishnan, J. Rainwater

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Several types of solutions exist for multiple target tracking. These techniques are computation-intensive and in some cases very difficult to operate online. The authors report on a backpropagation neural network which has been successfully used to identify multiple moving targets using kinematic data (time, range, range-rate and azimuth angle) from sensors to train the network. Preliminary results from simulated scenarios show that neural networks are capable of learning target identification for three targets during the time period used during training and a time period shortly after. This effective classification period can be extended by the use of networks in coordination …

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Genericity And Singularities Of Robot Manipulators, Ming-Chuan Leu, D. K. Pai Jan 1992

Genericity And Singularities Of Robot Manipulators, Ming-Chuan Leu, D. K. Pai

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The kinematic singularities of robot manipulators are studied from the point of view of the theory of singularities. The notion of a "generic'' kinematic map, whose singularities form smooth manifolds of prescribed dimension in the joint space of the manipulator, is examined. For three-joint robots, an equivalent algebraic condition for genericity using the Jacobian determinants is derived. This condition lends itself to symbolic computation and is sufficient for the study of decoupled manipulators. Orientation and translation singularities of manipulators are studied in detail. A complete characterization of orientation singularities of robots with any number of joints is given. The translation …

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Moving Object Recognition And Guidance Of Robots Using Neural Networks, Abhijit Neogy, S. N. Balakrishnan, Cihan H. Dagli Jan 1992

Moving Object Recognition And Guidance Of Robots Using Neural Networks, Abhijit Neogy, S. N. Balakrishnan, Cihan H. Dagli

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The design of a robust guidance system for a robot is discussed. The two major tasks for this guidance system are the online recognition of a moving object invariant to rotation and translation, and tracking the moving object using a neural-network-driven vision system. This system included computer software ported to the IBM PC and interfaced with an IBM 7535 robot. The operation of this guidance system involved recognition of a moving object and the ability to track it till the robot and effector was in close proximity of the object. It was found that the robot was able to track …

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Grain Size Effect On The Induced Piezoelectric Properties Of 0.9pmn-0.1pt Ceramic, U. Kumar, Wayne Huebner, P. Marsh, H. Kankul, S. F. Wang, Clyde G. Oakley Jan 1992

Grain Size Effect On The Induced Piezoelectric Properties Of 0.9pmn-0.1pt Ceramic, U. Kumar, Wayne Huebner, P. Marsh, H. Kankul, S. F. Wang, Clyde G. Oakley

Materials Science and Engineering Faculty Research & Creative Works

Lead magnesium niobate-lead titanate (Pb(Mg1/3Nb2/3)O3 - PbTiO3 (PT) solid solutions have been widely researched to produce devices that can be used in low- and high-electric-field applications. For some applications, such as medical ultrasonic transducers, it is necessary to prepare the ceramic with high density and small average grain size. The effect of grain size on the low- and high-field properties of 0.9-PMN-0.10-PT ceramics is described in the present work. To prepare highly dense ceramic, vibratory and attrition milled powders were sintered between 1000 and 1250 ⁰C. The average grain sizes of the sintered ceramics …

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High Pressure Lubricooling Machining Of Metals, Marian Mazurkiewicz Jan 1992

High Pressure Lubricooling Machining Of Metals, Marian Mazurkiewicz

Mining Engineering Faculty Research & Creative Works

A method of machining metals, by effecting relative movement between a work piece and a tool having a cutting edge to cut the work piece and produce a chip, including injecting a high pressure jet of cooling liquid into the cutting zone during machining, the jet being at a pressure of at least about 5,000 p.s.i. The jet is preferably injected between the chip and the rake face of the cutting tool, and the trajectory of the jet is offset from the rake face of the cutting tool by a small amount and the jet is aimed at the cutting …

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Hierarchical Neurocontroller Architecture For Robotic Manipulation, Xavier J. R. Avula, Luis C. Rabelo Jan 1992

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

Chemical and Biochemical 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 network system participates in the delineation of the robot arm workspace and coordinates transformation and the motion decision-making process. The lower-level network provides the correct sequence of control actions. A straightforward example illustrates the architecture''s capabilities, including speed, adaptability, and computational efficiency

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Planning And Control Of A Robotic Manipulator Using Neural Networks, Xavier J. R. Avula, Heng Ma, Anil Malkani, Jay-Shinn Tsai, Luis C. Rabelo Jan 1992

Planning And Control Of A Robotic Manipulator Using Neural Networks, Xavier J. R. Avula, Heng Ma, Anil Malkani, Jay-Shinn Tsai, Luis C. Rabelo

Chemical and Biochemical Engineering Faculty Research & Creative Works

An architecture which utilizes two artificial neural systems for planning and control of a robotic arm is presented. The first neural network system participates in the trajectory planning and the motion decision-making process. The second neural network system provides the correct sequence of control actions with a high accuracy due to the utilization of an unsupervised/supervised neural network scheme. The utilization of a hybrid hierarchical/distributed organization, supervised/unsupervised learning models, and forward modeling yielded an architecture with capabilities of high level functionality.

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Efficient Simulation Of Multi-Carrier Digital Communication Systems In Nonlinear Channel Environments, K. W. Schneider, William H. Tranter Jan 1992

Efficient Simulation Of Multi-Carrier Digital Communication Systems In Nonlinear Channel Environments, K. W. Schneider, William H. Tranter

Electrical and Computer Engineering Faculty Research & Creative Works

For systems that contain both frequency division multiplexing and bandpass nonlinearities, the high sampling rate that is necessary for accurate simulation contributes to the long runtimes. A partial sum of products (ParSOP) method is proposed to reduce the sampling rate of such systems. The ParSOP method allows the simulation sampling frequency to be reduced by only generating those intermodulation products that are centered in the bandwidth of the single observed modulated subcarrier. Simulation results, obtained by using the complex power series nonlinear model on a filtered binary phase shift keying system, showed that a reduction in the simulation runtime by …

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The Error Probability Of Reed-Solomon Coding And Interleaving On A Bursty-Noise Channel, W. J. Ebel, William H. Tranter Jan 1992

The Error Probability Of Reed-Solomon Coding And Interleaving On A Bursty-Noise Channel, W. J. Ebel, William H. Tranter

Electrical and Computer Engineering Faculty Research & Creative Works

A useful bursty-noise channel model is proposed and, using this model, a binary communication system using Reed-Solomon coding and interleaving is analyzed. The model includes both thermal noise, which gives rise to random errors, and burst noise, which gives rise to error bursts. Error probabilities are derived for the uncoded system, and error probability bounds are derived for the coded system. Monte Carlo simulation results agree well with theory.

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The Management Of Change: A Case Study, Stephen A. Raper, Richard Neal Callahan Jan 1992

The Management Of Change: A Case Study, Stephen A. Raper, Richard Neal Callahan

Engineering Management and Systems Engineering Faculty Research & Creative Works

A literature review was conducted to identify some of the requirements for competitiveness and change that are being promoted by leaders in the manufacturing field. A survey was developed based on the literature review and was subsequently administered, via the case study method, at a midwestern US agricultural chemicals firm to determine the company's degree of compliance with the literature''s recommendations. To a large degree, the company complied with the requirements.

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An Optical Implementation Of Adaptive Resonance Utilizing Phase Conjugation, Donald C. Wunsch, T. P. Caudell, D. J. Morris, R. A. Falk Jan 1992

An Optical Implementation Of Adaptive Resonance Utilizing Phase Conjugation, Donald C. Wunsch, T. P. Caudell, D. J. Morris, R. A. Falk

Electrical and Computer Engineering Faculty Research & Creative Works

A novel adaptive resonance theory (ART) device has been conceived that is fully optical in the input-output processing path. This device is based on holographic information processing in a phase-conjugating crystal. This sets up an associative pattern retrieval in a resonating loop utilizing angle-multiplexed reference beams for pattern classification. A reset mechanism is used to reject any given beam, allowing an ART search strategy. The design is similar to that of an existing nonlearning optical associative memory, but is does allow learning and makes use of information the other device discards. This new device is expected to offer higher information …

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Application Of Total Quality Management To Research And Development: An Historical Perspective, Scott A. Dellana, Henry Allen Wiebe Jan 1992

Application Of Total Quality Management To Research And Development: An Historical Perspective, Scott A. Dellana, Henry Allen Wiebe

Engineering Management and Systems Engineering Faculty Research & Creative Works

This paper discusses the historical applications of Total Quality Management (TQM) to Research and Development (R&D). Research aimed at establishing an effective model for the application of TQM philosophies and tools to the R&D environment must start from this historical perspective. The emphasis of this paper is on the relationship of quality tools and techniques to the application of TQM in R&D, providing the foundation for further model development. The scope and definition of R&D is presented and is followed by an overview of the TQM philosophy and its associated tools and techniques. Special attention is given to defining performance …

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