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Missouri University of Science and Technology

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1990

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Articles 1 - 30 of 62

Full-Text Articles in Engineering

Microwave Nondestructive Detection And Evaluation Of Disbonding And Delamination In Layered-Dielectric Slabs, R. Zoughi, Sasan Bakhtiari Dec 1990

Microwave Nondestructive Detection And Evaluation Of Disbonding And Delamination In Layered-Dielectric Slabs, R. Zoughi, Sasan Bakhtiari

Electrical and Computer Engineering Faculty Research & Creative Works

A microwave nondestructive technique for detection and evaluation of disbonding and delamination in layered-dielectric-slabs backed by a conducting plate is discussed. The theoretical development begins by considering an incident wave illuminating such a medium and then formulating the characteristics of the wave reflected by the metal plate. An effective reflection coefficient is determined in this way whose phase characteristics are used in the detection and evaluation of delaminations in the media. The characteristics of this phase as a function of several parameters such as delamination dielectric constant and thickness, slab dielectric constant, and thickness and the frequency of operation are …

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The Waveform Relaxation Method For Systems Of Differential/Algebraic Equations, Marija D. Ilić, Mariesa Crow Dec 1990

The Waveform Relaxation Method For Systems Of Differential/Algebraic Equations, Marija D. Ilić, Mariesa Crow

Electrical and Computer Engineering Faculty Research & Creative Works

An extension of the waveform relaxation (WR) algorithm to systems of differential/algebraic equations (DAE) is presented. Although this type of application has been explored earlier in relation to VLSI circuits, the algorithm has not been generalized to include the vast array of DAE system structures. The solvability and convergence requirements of the WR algorithm for higher-index systems are established. Many systems in robotics and control applications are modeled with DAE systems having an index greater than two. Computer simulation of these systems has been hampered by numerical integration methods which perform poorly and must be explicitly tailored to the system. …

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Fracture Toughening Of High Pressure Sintered Diamond And Carbide Ceramics, P. D. Ownby Nov 1990

Fracture Toughening Of High Pressure Sintered Diamond And Carbide Ceramics, P. D. Ownby

Materials Science and Engineering Faculty Research & Creative Works

High pressure sintered bodies of polycrystalline diamond or carbide ceramics are rendered more resistant to cracking by establishing dispersed, localized "stress centers" of submicron size particles of lonsdaleite, diamond, or other form of metastable, high density carbon which has the capability of transforming crystallographically to graphite in situ in the body. When an incipient crack in the body approaches entrapped metastable particles along its path, the crack promotes or permits transformation of the metastable particles to graphite particles, with concomitant increase in their size, thereby resisting further propagation of the crack.

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Design Of Automotive Structural Components Using High Strength Sheet Steels Structural Strength Of Cold-Formed Steel Members Under Dynamic Loads, Chi-Ling Pan, Wei-Wen Yu Nov 1990

Design Of Automotive Structural Components Using High Strength Sheet Steels Structural Strength Of Cold-Formed Steel Members Under Dynamic Loads, Chi-Ling Pan, Wei-Wen Yu

CCFSS Library (1939 - present)

INTRODUCTION During recent years, more economic and lighter vehicles have been produced by automotive manufacturers because of the high cost of fuel. High strength sheet steels have been favorably used to accomplish the construction of such automobiles. One source of the design information for using sheet steels is provided in the AISI Automotive Steel Design Manual 1. In view of the fact that material properties and stress-strain relationships of sheet steels can be influenced by the strain rate, the material properties of three different sheet steels (35XF, 50XF, and 100XF) have been studied at University of Missouri-Rolla. This study involved …

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Optimized Cross Correlation Waveforms For First Order Correlation Loops, Kurt Louis Kosbar Sep 1990

Optimized Cross Correlation Waveforms For First Order Correlation Loops, Kurt Louis Kosbar

Electrical and Computer Engineering Faculty Research & Creative Works

In this work, the steady state mean square tracking error of first order correlation loops is minimized by varying the locally generated cross correlation function produced by the voltage controlled oscillator. This analysis should assist in the design of modified first order delay locked loops used for pseudonoise code synchronization in direct sequence spread spectrum receivers. The optimum cross correlation waveform is generated by filtering a replica of the originally transmitted signal. The optimal filter imposes a 90 degree phase shift at all frequencies and has an amplitude response that is a function of the channel signal to noise ratio. …

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Method For Fabricating Or Modifying An Article Comprising The Removal Of A Polymer Coating, Bonnie Bachman, Elizabeth A. Hofstatter, Joan M. Ritter, Jerry J. Rubin Aug 1990

Method For Fabricating Or Modifying An Article Comprising The Removal Of A Polymer Coating, Bonnie Bachman, Elizabeth A. Hofstatter, Joan M. Ritter, Jerry J. Rubin

Economics Faculty Research & Creative Works

Disclosed is a method for removing poly-para-xylylene, its derivatives, and copolymers (collectively called "parylene") from bodies, including relatively large bodies such as printed circuit (PC) boards, that is capable of yielding relatively high removal rates. A body such as a PC board coated with parylene is placed into a reaction chamber downstream from a microwave plasma such that plasma discharge products generated by the microwave plasma react with the parylene, etching the parylene without exposing the body to bombardment by energetic ions and/or electrons. The plasma is generated from a gas mixture containing oxygen, a second gas, and optional additives …

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Recent Applications Of Glass Science, Norbert J. Kreidl Aug 1990

Recent Applications Of Glass Science, Norbert J. Kreidl

Materials Science and Engineering Faculty Research & Creative Works

Recent, often exciting, applications of glass science include solid state batteries, electronic switches and memories, electrophotography, solar cells, microspheres for optical strengthening and medical uses, novel glass ceramics such as machinable and bioactive materials, solder glasses, composites, sol-gel glasses, gradient index optics, communication fibers, sensors, non-linear and active optics, and, perhaps, digital optics. The large field of special coatings is not covered in this review. © 1990.

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Tests For Positive Jumps In The Intensity Of A Poisson Process: A Power Study, Max Engelhardt, James M. Guffey, F. T. Wright Aug 1990

Tests For Positive Jumps In The Intensity Of A Poisson Process: A Power Study, Max Engelhardt, James M. Guffey, F. T. Wright

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Tests are considered for the hypothesis of a constant intensity against the alternative of an intensity which increases with time in a nonhomogeneous Poisson process. Attention is focused on step-function alternatives and tests designed for such alternatives. One application is testing for abrupt changes in equipment following scheduled overhauls. The authors recommend the order-restricted likelihood-ratio test over an ordered chi-square test for such situations, provided the points at which jumps can occur are known. Otherwise, they recommend the test based on the Laplace statistic. The performance of these tests is evaluated for smooth alternatives, with the result that the smallest …

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Ccfss News August 1990, Wei-Wen Yu Center For Cold-Formed Steel Structures Aug 1990

Ccfss News August 1990, Wei-Wen Yu Center For Cold-Formed Steel Structures

CCFSS Newsletters (1999 - 2008)

No abstract provided.

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Load And Resistance Factor Design Of Cold-Formed Steel Reliability Based Criteria For Cold-Formed Steel Members, Ling-En Hsiao, Wei-Wen Yu, Theodore V. Galambos Aug 1990

Load And Resistance Factor Design Of Cold-Formed Steel Reliability Based Criteria For Cold-Formed Steel Members, Ling-En Hsiao, Wei-Wen Yu, Theodore V. Galambos

CCFSS Library (1939 - present)

In the design of steel buildings, the "Allowable Stress Design (ASD)" method has long been used for cold-formed steel structural members in the United States and other countries. In this approach, member forces, or moments, determined on the basis of working loads should not exceed the allowable values. The allowable value is used to prevent the possible structural failure by using an appropriate factor of safety selected primarily on the basis of engineering judgment and long-time experience. Recently, in the United States, the concepts of risk and reliability analysis have been successfully applied to the Load and Resistance Factor Design …

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A Knowledge-Based Expert System For Managing Underground Coal Mines In The U.S., H. Singh, S. Yuan, C. M. Watts, J. M. Dean, N. P. Reddy, R. S. Nutter Jr., R. Larry Grayson Jul 1990

A Knowledge-Based Expert System For Managing Underground Coal Mines In The U.S., H. Singh, S. Yuan, C. M. Watts, J. M. Dean, N. P. Reddy, R. S. Nutter Jr., R. Larry Grayson

Mining Engineering Faculty Research & Creative Works

The Mine Management Support System which is being developed as a knowledge-based expert system for better management of underground coal mines, is presented. Concentrating on capturing the complex body of knowledge needed to enhance efficient management of a mine, it will encompass information and preferred rules on work scheduling, work practices, regulations impinging on the accomplishment of work, responses to operating problems, and the labor-management work agreement. Different components of the mine system, modeled using an object-oriented layering technique, are displayed graphically to aid in coordinating work plans and to present locations of equipment, supplies, and proposed subsystem components.

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Parallel Implementation Of A Recursive Least Squares Neural Network Training Method On The Intel Ipsc/2, James Edward Steck, Bruce M. Mcmillin, K. Krishnamurthy, M. Reza Ashouri, Gary G. Leininger Jun 1990

Parallel Implementation Of A Recursive Least Squares Neural Network Training Method On The Intel Ipsc/2, James Edward Steck, Bruce M. Mcmillin, K. Krishnamurthy, M. Reza Ashouri, Gary G. Leininger

Computer Science Faculty Research & Creative Works

An algorithm based on the Marquardt-Levenberg least-square optimization method has been shown by S. Kollias and D. Anastassiou (IEEE Trans. on Circuits Syst. vol.36, no.8, p.1092-101, Aug. 1989) to be a much more efficient training method than gradient descent, when applied to some small feedforward neural networks. Yet, for many applications, the increase in computational complexity of the method outweighs any gain in learning rate obtained over current training methods. However, the least-squares method can be more efficiently implemented on parallel architectures than standard methods. This is demonstrated by comparing computation times and learning rates for the least-squares method implemented …

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Thermoelastic Problems Of Multilayered Cylinders, Victor Birman May 1990

Thermoelastic Problems Of Multilayered Cylinders, Victor Birman

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Thermoelastic problems of long multilayered cylinders manufactured from isotropic materials are considered. The steady-state thermal field corresponding to a constant difference between temperature outside and inside the assembly is used in the analysis. Both the case of a hollow cylinder and that of a solid multilayered assembly are discussed. A closed-form exact solution is shown for an arbitrary number of layers if the properties of constituent materials remain unaffected by temperature. Various strategies leading to an analytical solution are proposed for the case where material properties depend on temperature. The stresses in a dual-coated optical fiber subject to a uniform …

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Design Of Automotive Structural Components Using High Strength Sheet Steels Structural Strengths Of Cold-Formed Steel Members Under Dynamic Loads, Maher Kassar, Wei-Wen Yu May 1990

Design Of Automotive Structural Components Using High Strength Sheet Steels Structural Strengths Of Cold-Formed Steel Members Under Dynamic Loads, Maher Kassar, Wei-Wen Yu

CCFSS Library (1939 - present)

INTRODUCTION Since May 1988, the research project on automotive components sponsored by American Iron and Steel Institute (AISI) at University of Missouri-Rolla (UMR) has been concentrated on a study of the effect of strain rate on mechanical properties of sheet steels and the structural behavior and strength of cold-formed steel members subjected to impact loads. The results of the static and dynamic tensile mechanical properties of three selected sheet steels in the virgin condition as well as for the steels subjected to different amount of cold stretchings, were established in 1988 and early 1989. Details of the tension coupon tests …

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Design Of Automotive Structural Components Using High Strength Sheet Steels Effect Of Strain Rate On Material Properties Of Sheet Steels And Structural Strengths Of Cold-Formed Steel Members, Maher Kassar, Wei-Wen Yu May 1990

Design Of Automotive Structural Components Using High Strength Sheet Steels Effect Of Strain Rate On Material Properties Of Sheet Steels And Structural Strengths Of Cold-Formed Steel Members, Maher Kassar, Wei-Wen Yu

CCFSS Library (1939 - present)

In structural design, the material properties of steels and the strengths of cold-formed steel members are affected by strain rate. Two subjects were investigated experimentally and analytically in this study. They are 1) effect of strain rate on mechanical properties of sheet steels in tension and compression, and 2) structural strengths of stub columns and beams subjected to dynamic loads. Three sheet steels with nominal yield strengths ranging from 35 to 100 ksi were studied under different strain rates. A total of 124 tensile coupons and 54 compressive coupons were tested in this phase of study. The structural strengths of …

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The Parallel Implementation Of The Waveform Relaxation Method For The Simulation Of Structure-Preserved Power Systems, Marija D. Ilić, Mariesa Crow May 1990

The Parallel Implementation Of The Waveform Relaxation Method For The Simulation Of Structure-Preserved Power Systems, Marija D. Ilić, Mariesa Crow

Electrical and Computer Engineering Faculty Research & Creative Works

Several results pertaining to the partitioning of the waveform relaxation (WR) algorithm for dynamic simulation are presented. The WR algorithm is extended to a structure-preserving power system model in which the loads are retained. This results in a system of differential/algebraic equations (DAEs). Power systems are shown to exhibit several dynamic characteristics which make them suitable for simulation by the WR method. A heuristic method for determining a fault-dependent partitioning of the power system for parallel implementation is given.

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Electrochemical Evaluation Of Copper Deposition With Gas Sparging, D. A. Uceda, Thomas J. O'Keefe Mar 1990

Electrochemical Evaluation Of Copper Deposition With Gas Sparging, D. A. Uceda, Thomas J. O'Keefe

Materials Science and Engineering Faculty Research & Creative Works

The influence of gas sparging during copper electrolysis was studied using standard electrochemical techniques. The polarization behavior of acid copper electrolytes was determined in the presence and absence of gas sparging on vertical electrodes. Tracer ion techniques were employed to determine the effect of gas sparging and forced circulation of the electrolyte on the mass transfer characteristics of the system. In addition to the potentiodynamic scans, 3-h copper deposits were produced for morphology and orientation studies. The effect of current density and temperature on deposition were also studied. The polarization experiments have shown that a mass transfer component becomes evident …

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The Effects Of Lead On The Electrochemical And Adhesion Behavior Of Zinc Electrodeposits, Vijay Srinivasan, J. Sami Cuzmar, Thomas J. O'Keefe Feb 1990

The Effects Of Lead On The Electrochemical And Adhesion Behavior Of Zinc Electrodeposits, Vijay Srinivasan, J. Sami Cuzmar, Thomas J. O'Keefe

Materials Science and Engineering Faculty Research & Creative Works

The presence of excessive lead in zinc sulfate electrolytes can lead to problems related to both processing efficiency and the properties of the metal produced. For example, poor adhesion can occur in electrogalvanized steel when it is heated in the temperature range of 215 °C to 280 °C if lead is present in the deposit. The duration of heating necessary to induce the peeling of the zinc was found to be dependent on the temperature, time, and concentration of lead in the electrolyte and the plating parameters. The presence of lead slowed the formation of the intermetallic, and the peeling …

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Tests Of Full Scale Brick Veneer Steel Stud Walls To Determine Strength And Rain Penetration Characteristics, Michael J. Wilson, A. S. Essawy, A. Kluge Jan 1990

Tests Of Full Scale Brick Veneer Steel Stud Walls To Determine Strength And Rain Penetration Characteristics, Michael J. Wilson, A. S. Essawy, A. Kluge

CCFSS Library (1939 - present)

The design, construction and physical testing of five full scale (2.75 m x 5.2 m) brick veneer rain screen wall specimens are reported. Also, the documentation of the design and fabrication of a new test apparatus and of the development of test procedures are major components of the report. The test program included sequences of air pressure loading stages both with and without simulated rain to establish both the structural and rain penetration performances of the test walls. The test walls included four brick veneer/steel stud specimens and one brick veneer/concrete block specimen. Additional tests were performed on bricks, mortar …

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Robust Nonlinear Control Of Brushless Dc Motors For Direct-Drive Robotic Applications, N. Hemati, J. S. Thorp, Ming-Chuan Leu Jan 1990

Robust Nonlinear Control Of Brushless Dc Motors For Direct-Drive Robotic Applications, N. Hemati, J. S. Thorp, Ming-Chuan Leu

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The control problem associated with brushless DC motors (BLDCMs) for direct-drive robotic applications is considered. In order to guarantee the high-performance operation of BLDCMs in such applications, the effects of reluctance variations and magnetic saturation are accounted for in the model. Such a BLDCM model constitutes a highly coupled and nonlinear dynamic system. Using the transformation theory of nonlinear systems, a feedback control law, which is shown to compensate for the system nonlinearities, is derived. Conditions under which such a control law is possible are presented. The need for the derivation of explicit commutation strategies is eliminated, resulting in reduction …

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A Differential Equation Approach To Swept Volumes, Ming-Chuan Leu, Denis Blackmore Jan 1990

A Differential Equation Approach To Swept Volumes, Ming-Chuan Leu, Denis Blackmore

Mechanical and Aerospace Engineering Faculty Research & Creative Works

An approach to the analysis of swept volumes is introduced. It is shown that every smooth Euclidean motion or sweep, can be identified with a first-order, linear, ordinary differential equation. This sweep differential equation provides useful insights into the topological and geometrical nature of the swept volume of an object. A certain class, autonomous sweeps, is identified by the form of the associated differential equation, and several properties of the swept volumes of the members of this class are analyzed. The results are applied to generate swept volumes for a number of objects. Implementation of the sweep differential equation approach …

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A Parallel Architecture For Stock Cutting Problem, Cihan H. Dagli, Alireza Hajakbari Jan 1990

A Parallel Architecture For Stock Cutting Problem, Cihan H. Dagli, Alireza Hajakbari

Engineering Management and Systems Engineering Faculty Research & Creative Works

The problem of allocating irregular patterns arises frequently in applications where it has to be determined how a set of two-dimensional shapes will fit onto a stock sheet of finite dimensions with minimum waste. The use of the simulated annealing approach for the solution of this problem is described

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Cost Justification Of An Expert System, Alice E. Smith, Cihan H. Dagli Jan 1990

Cost Justification Of An Expert System, Alice E. Smith, Cihan H. Dagli

Engineering Management and Systems Engineering Faculty Research & Creative Works

It is pointed out that, like other projects which spend corporate dollars, an expert system must be analyzed for its economic and strategic worth to the organization. Both traditional engineering economy project analysis and multivariate holistic methods can be applicable. The fundamental strategy of the analyst is to decide upon the evaluation methodologies, gather cost and benefit data, study the project from various perspectives, and present the results and recommendations.

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Simulated Annealing Approach For Solving Stock Cutting Problem, Cihan H. Dagli, Alireza Hajakbari Jan 1990

Simulated Annealing Approach For Solving Stock Cutting Problem, Cihan H. Dagli, Alireza Hajakbari

Engineering Management and Systems Engineering Faculty Research & Creative Works

The simulated annealing approach is applied to stock cutting. The conceptual approach proposed uses an energy function that measures the area of the rectangular enclosure of all the patterns to be nested, the level of similarity between pattern pairs, and the amount of overlap among patterns in evaluating various pattern configurations to be generated by the simulated annealing algorithm. Three methods for pattern configuration generation are considered. The first method uses heuristics to generate the initial configuration. The second and third methods use random selection and random placement of patterns

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Neural Networks In Manufacturing: Possible Impacts On Cutting Stock Problems, Cihan H. Dagli Jan 1990

Neural Networks In Manufacturing: Possible Impacts On Cutting Stock Problems, Cihan H. Dagli

Engineering Management and Systems Engineering Faculty Research & Creative Works

The potential of neural networks is examined, and the effect of parallel processing on the solution of the stock-cutting problem is assessed. The conceptual model proposed integrates a feature-recognition network and a simulated annealing approach. The model uses a neocognitron neural network paradigm to generate data for assessing the degree of match between two irregular patterns. The information generated through the feature recognition network is passed to an energy function, and the optimal configuration of patterns is computed using a simulated annealing algorithm. Basics of the approach are demonstrated with an example.

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Knowledge-Based Prototype For Improving Scheduling Productivity, Colin Othniel Benjamin, Daniel L. Babcock, N. B. Yunus, John B. Kincaid Jan 1990

Knowledge-Based Prototype For Improving Scheduling Productivity, Colin Othniel Benjamin, Daniel L. Babcock, N. B. Yunus, John B. Kincaid

Engineering Management and Systems Engineering Faculty Research & Creative Works

The development of efficient construction plans and schedules presents continuing challenges to construction schedulers. Knowledge-based systems offer considerable potential as computer-based planning tools to aid the development of realistic project plans and schedules. This paper outlines the development of a knowledge-based prototype system for construction planning and scheduling and evaluates its effectiveness as a tool for improving the productivity of inexperienced construction project schedulers. The prototype, developed using the M.1 knowledge engineering shell, incorporates data bases, algorithm, and heuristics that mimic the decision process of expert construction project schedulers and identifies a work breakdown structure and precedence relationships. Inexperienced schedulers …

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A Balancing Method For Reduced Order Modelling Of Unstable Systems, Rajiva Prakash, Vittal S. Rao Jan 1990

A Balancing Method For Reduced Order Modelling Of Unstable Systems, Rajiva Prakash, Vittal S. Rao

Electrical and Computer Engineering Faculty Research & Creative Works

Moore's balancing method of model reduction has many attractive properties and is used widely in practice. However, this method suffers from the drawback that it is not applicable for unstable systems. This paper introduces a balancing method of model reduction to overcome this problem. The proposed technique obtains the reduced order model by balancing and truncating frequency domain controllability and observability Gramians. Analytical treatment is given for associated properties of the Gramians, and the balancing and truncation steps of model reduction. A numerical example is used to demonstrate the new approach. © 1990.

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Comments On The Papers By Kê And Su, Hollis P. Leighly Jan 1990

Comments On The Papers By Kê And Su, Hollis P. Leighly

Materials Science and Engineering Faculty Research & Creative Works

No abstract provided.

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Oxidation-Reduction Behavior Of Undoped And Sr-Doped Lamno3: Defect Structure, Electrical Conductivity, And Thermoelectric Power, J. H. Kuo, Harlan U. Anderson, Don M. Sparlin Jan 1990

Oxidation-Reduction Behavior Of Undoped And Sr-Doped Lamno3: Defect Structure, Electrical Conductivity, And Thermoelectric Power, J. H. Kuo, Harlan U. Anderson, Don M. Sparlin

Materials Science and Engineering Faculty Research & Creative Works

Seebeck coefficient and electrical conductivity measurements were performed for undoped and Sr-doped LaMnO3 as a function of temperature and oxygen partial pressure. The results of electrical conductivity showed typical p-type behavior. As reduction proceeded, the electrical conductivity of these LaMnO3-based perovskites decreased with P 1 4O2. The analysis of the electrical conductivity data was performed by extending the defect model from a previous thermogravimetric (TG) study. The measured Seebeck coefficients were found to be positive except for the most reducing conditions when the decomposition into multiple phases occurred. The Heikes formula was adopted to interpret …

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Production Of Thin Copper Foils On Microporous Titanium Oxide Substrates, J. L. Delplancke, M. Sun, Thomas J. O'Keefe, R. Winand Jan 1990

Production Of Thin Copper Foils On Microporous Titanium Oxide Substrates, J. L. Delplancke, M. Sun, Thomas J. O'Keefe, R. Winand

Materials Science and Engineering Faculty Research & Creative Works

This study deals with the electrochemical production of thin (35 μm) copper films on anodized titanium substrates. The formation of a microporous oxide layer on the titanium electrodes greatly enhances the surface density of copper nuclei during a potentiostatic experiment so that a complete coverage of the cathode surfaces may be obtained after short term (20 s) polarization. Moreover, the oxide film may act as a parting agent and the copper films may be easily stripped from their substrates. The higher the pore density of the oxide film, the higher the surface density of nuclei and the easier the foil's …

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