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1990

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Articles 1 - 30 of 182

Full-Text Articles in Mechanical Engineering

Free Energy Simulation Of Grain Boundary Segregation And Thermodynamics In Ni3−Xal1+X, R. Najafabadi, H.Y. Wang, D. J. Srolovitz, Richard Alan Lesar Nov 1990

Free Energy Simulation Of Grain Boundary Segregation And Thermodynamics In Ni3−Xal1+X, R. Najafabadi, H.Y. Wang, D. J. Srolovitz, Richard Alan Lesar

Richard Alan Lesar

The free energy simulation method is employed to study segregation to Σ5 and Σ13 (001) twist grain boundaries and their free energies in ordered Ni3−xAl1+x. In the temperature range studied (300–900K), it is shown that there is almost no segregation, strong Al segregation, and weak Ni segregation to the grain boundary for the stoichiometric, Al-rich, and Ni-rich bulk compositions respectively. It is also shown that the segregation is limited to a few (002) planes around the grain boundary and its magnitude decreases with increasing temperature. For Al-rich bulk composition, it is demonstrated that segregation at low temperature ...


Advanced Space Design Program, William W. Durgin, Francis C. Lutz Nov 1990

Advanced Space Design Program, William W. Durgin, Francis C. Lutz

Office of the Provost and Vice President of Academic Affairs Scholarship

Worcester Polytechnic Institute's Advanced Space Design (ASD) Program provides project-based design experiences that combine a highly motivating, need-to-know experience with an integrative capstone design that draws on the know-how of practitioners in the profession. Mechanical engineering students work with their counterparts in electrical, chemical, and civil engineering to develop integrated packages of experiments to be conducted in the micro-gravity environment of space.


Ole Miss Engineer 1990 Oct 1990

Ole Miss Engineer 1990

The Ole Miss Engineer

No abstract provided.


Stability Of Core-Annular Flow With Very Small Viscosity Ratio, Howard H. Hu, Thomas S. Lundgren, Daniel D. Joseph Jul 1990

Stability Of Core-Annular Flow With Very Small Viscosity Ratio, Howard H. Hu, Thomas S. Lundgren, Daniel D. Joseph

Departmental Papers (MEAM)

It is known that the stability problem for core-annular flow of very viscous crude oil and water is singular, the water annulus appears to be inviscid with boundary layers at the pipe wall and at the interface. In the present paper, this singular problem is treated by the method of matched asymptotic expansions using = m/ℝα as a small parameter. There are two cases of instability corresponding to different positions of the critical point in the annulus. One case is when the critical point is far away from the interface, the other is when the critical point is close ...


Synergy Of Artificial Neural Networks And Knowledge-Based Expert Systems For Intelligent Fms Scheduling, Luis Carlos Rabelo, Sema E. Alptekin, Ali S. Kiran Jun 1990

Synergy Of Artificial Neural Networks And Knowledge-Based Expert Systems For Intelligent Fms Scheduling, Luis Carlos Rabelo, Sema E. Alptekin, Ali S. Kiran

Industrial and Manufacturing Engineering

In this paper we describe a hybrid architecture that integrates artificial neural networks and knowledge-based expert systems to generate solutions for the real time scheduling of flexible manufacturing systems. The artificial neural networks perform pattern recognition and, due to their inherent characteristics, support the implementation of automated knowledge acquisition and refinement schemes through a feedback mechanism. The artificial neural network structures enable the system to recognize patterns in the tasks to be solved in order to select the best scheduling rule according to different demands. The knowledge-based expert systems are the higher order elements which drive the inference strategy and ...


Coke Oven Emissions: A Case Study Of Technology-Based Regulation, John D. Graham, David R. Holtgrave Jun 1990

Coke Oven Emissions: A Case Study Of Technology-Based Regulation, John D. Graham, David R. Holtgrave

RISK: Health, Safety & Environment (1990-2002)

After examining and analyzing the experience with coke ovens, the authors conclude that attempts to force technology beyond its demonstrated competence can be both expensive and ineffective in controlling hazards. They also suggest implications for pending proposals to further control air pollution.


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 ...


Correlation Between Particle Velocities And Conditions Of Abrasive Waterjet Formation, Wei-Long Chen May 1990

Correlation Between Particle Velocities And Conditions Of Abrasive Waterjet Formation, Wei-Long Chen

Dissertations

The velocities of water and abrasive particles in abrasive waterjet(AWJ) were measured by the use of Laser Transit Anemometer(LTA). A setup for the velocity measurement was constructed and a statistical technique was used to improve the accuracy of the velocity determination. A comparison of the magnitude of velocities determined by LTA, Piezoelectric Force Transducer and Schlieren Photograph clearly indicates the feasibility of the use of LTA.

The velocities of water and particles were measured for different diameters of water and slurry nozzles, abrasive mass flow rates and particle sizes. The performed experiments enabled us to evaluate the effects ...


On Local Stresses And Spring Constants Of Pipe-Nozzle Connection, Hson-Chih Sun May 1990

On Local Stresses And Spring Constants Of Pipe-Nozzle Connection, Hson-Chih Sun

Dissertations

This thesis presents a comprehensive study of local stresses and spring coefficients of pipe with a nozzle connection, analyzed by the finite element method (FEM). Six types of loading are discussed: radial force, circumferential moment, longitudinal moment, circumferential shear force, longitudinal shear force, and torsional moment.

For the local stresses, the bending and membrane stress factors due to each of these loadings are presented in a series of plots with various gamma (piping radius/thick-ness) and beta (nozzle radius/pipe radius) values. These stress factors will readily replace those previously published in WRC No. 107. This work not only gives ...


Simulation Of Random Packing Of Hard Spheres Using Monte Carlo Method, Sung-Ho Park May 1990

Simulation Of Random Packing Of Hard Spheres Using Monte Carlo Method, Sung-Ho Park

Theses

A computer based method of generating a random packing of hard spheres is described. Using a Monte Carlo method as employed in the field of Computational Statistical Physics, packing of hard spheres are generated and analyzed.

The mean packing fractions for the present assemblies of 1000 spheres are 0.555±0.015 after pouring and 0.582±0.018 after 10 cycles of shaking. These values are approximately 5 to 6 per cent lower than the experimental results of G.D. Scott[30], but similar with the result of Visscher & Bolsterli [17].

The mean coordination numbers are 5.97 and ...


An Investigation Of The Dynamics Of Abrasive Waterjet Formation, Md. Ekramul Hasan Khan May 1990

An Investigation Of The Dynamics Of Abrasive Waterjet Formation, Md. Ekramul Hasan Khan

Theses

The aim of this research was to investigate the jet formation and the jet behavior, as characterized by the velocity field, the force exerted by the jet on a work-piece and the jet geometry. The velocity and force distributions were measured using a laser transit anemometer (LTA) and a piezoelectric force transducer (PFT) respectively for constant water pressure (334.6 MPa) supply. The jet structure and its instantaneous behavior were visualized by the used of high speed filming. LTA and PFT measuring techniques were established and verified. The measurements were performed under different operating conditions. It was found that at ...


Statistical Process Control For High Precision Deep Drawn Sheet Metal Parts, Sunil S. Shah May 1990

Statistical Process Control For High Precision Deep Drawn Sheet Metal Parts, Sunil S. Shah

Theses

In today's world, industrial expertise has come to be judged in terms of the quality of the product. Good quality has become the ultimate aim in a manufacturing environment, which leads to many innovations for ease in the inspection of parts. In considering a metal working company like Hudson Tool & Die Company, a study of the various operations and the application of Statistical Process Control to the forming operations is performed using STORM software. Important characteristics have been carefully studied with regards to metal forming like uniform metal thickness, radius of the bend, depth of the drawing operation. In-depth ...


A Comparative Study Of Edge Detection Techniques, Jaskaran Singh Dhaliwal May 1990

A Comparative Study Of Edge Detection Techniques, Jaskaran Singh Dhaliwal

Theses

The problem of detecting edges in gray level digital images is considered. A literature survey of the existing methods is presented. Based on the survey, two methods that are well accepted by a majority of investigators are identified. The methods selected are: 1) Laplacian of Gaussian (LoG) operator, and 2) An optimal detector based on maxima in gradient magnitude of a Gaussian-smoothed image. The latter has been proposed by Canny[], and will be referred as Canny's method. The purpose of the thesis is to compare the performance of these popular methods. In order to increase the scope of such ...


A Suggested Model Program For Cim Education, Sema E. Alptekin May 1990

A Suggested Model Program For Cim Education, Sema E. Alptekin

Industrial and Manufacturing Engineering

No abstract provided.


Adaptive Scheduling And Control Using Artificial Neural Networks And Expert Systems For A Hierarchical/Distributed Fms Architecture, Luis Carlos Rabelo, Sema E. Alptekin May 1990

Adaptive Scheduling And Control Using Artificial Neural Networks And Expert Systems For A Hierarchical/Distributed Fms Architecture, Luis Carlos Rabelo, Sema E. Alptekin

Industrial and Manufacturing Engineering

An adaptive expert scheduler was developed that learns by itself and adapts to the dynamic FMS environment. This hybrid system uses a symbiotic architecture composed of expert systems (ESs) and artificial neural networks (ANNs) and provides a learning scheme guided by past experience. The artificial neural networks recognize patterns in the tasks to be solved in order to select the best scheduling rule according to different criteria. The expert systems, on the other hand, drive the inference strategy and interpret the constraints and restrictions imposed by the upper levels of the control hierarchy of the flexible manufacturing system. The level ...


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 ...


Kinematics Of Redundantly Actuated Closed Chains, Vijay Kumar, John F. Gardner Apr 1990

Kinematics Of Redundantly Actuated Closed Chains, Vijay Kumar, John F. Gardner

Departmental Papers (MEAM)

The instantaneous kinematics of a hybrid manipulation system, which combines the traditional serial chain geometry with parallelism in actuation, and the problem of coordination is discussed. The indeterminacy and singularities in the inverse kinematics and statics equations and measures of kinematic performance are analyzed. Finally, coordination algorithms that maintain an optimal force distribution between the actuators while avoiding or exploiting singularities are presented.


Data Communication Between An Expert System Shell And A Conventional Algorithmic Program With Application To Cam Motion Specification, Paul P. Lin, An-Jen Yang Apr 1990

Data Communication Between An Expert System Shell And A Conventional Algorithmic Program With Application To Cam Motion Specification, Paul P. Lin, An-Jen Yang

Mechanical Engineering Faculty Publications

Although more and more expert system shells have begun to provide communication interfaces to conventional procedural languages, the interfaces are basically shell- and language-dependent. This paper presents a simple, shell- and language-independent data communication technique between a shell and a procedural language via a concept analogous to the handshake data transmission used in microprocessors. A control file is used for the action of handshake. The communication interface is between two data files in two different language environments. A program written in a LISP-based expert system shell, OPS 5, and one written in a procedural language, FORTRAN, were tested to verify ...


Determination Of The Formation Of The 1/6[031] Extrinsic Stacking Faults In Deformed Yba2cu3o7−Δ, Matthew J. Kramer, E. P. Kvam, L. Scott Chumbley Apr 1990

Determination Of The Formation Of The 1/6[031] Extrinsic Stacking Faults In Deformed Yba2cu3o7−Δ, Matthew J. Kramer, E. P. Kvam, L. Scott Chumbley

Ames Laboratory Conference Papers, Posters, and Presentations

Mechanial deformation of the YBa2Cu3O7−δ high temperature superconductor under a number of different processing conditions resulted in the formation of and edge dislocations, both having a (001) slip plane. Subsequent high temperature annealing at 900°C resulted in the formation of extrinsic stacking faults with a large separation of the partial dislocations, up to 0.35 μm, suggesting a very low minimum stacking fault energy of 1.2 × 10−2 J/m2. High resolution transmission electron microscopy (HRTEM) in conjunction with image simulations revealed that the stacking faults were comprised of an extra ...


Ole Miss Engineer 1990 Apr 1990

Ole Miss Engineer 1990

The Ole Miss Engineer

No abstract provided.


Method Of Magnetizing Nonmagnetic Materials, Jiann-Yang Hwang Mar 1990

Method Of Magnetizing Nonmagnetic Materials, Jiann-Yang Hwang

Michigan Tech Patents

Particles of a nonmagnetic material are rendered magnetic by contacting their surfaces with a magnetizing reagent comprising water containing particles of a magnetic material, each of which has a two layer surfactant coating including an inner layer and an outer layer. The inner layer covers the magnetic particle and is a mono- molecular layer of a first water soluble, organic, hetero- polar surfactant containing at least 3 carbon atoms and having a functional group on one end which bonds with the magnetic particle. The outer layer coats the inner layer and is a monomolecular layer of a second water soluble ...


A Transient Electromagnetic Flowmeter And Calibration Facility, Paul J. Lefebvre, William W. Durgin Mar 1990

A Transient Electromagnetic Flowmeter And Calibration Facility, Paul J. Lefebvre, William W. Durgin

Office of the Provost and Vice President of Academic Affairs Scholarship

An electromagnetic flowmeter was developed to measure transient flows at a data rate of 60 Hz. The approach taken was to develop suitable electronics to replace the electronics of a commercially available electromagnetic flowmeter normally used for steady-state operation. Use of the commercially available flowmeter body, which includes the magnetic coils, core, and signal electrodes, provided a relatively economical means of fabricating the transient flowmeter. A transient flow calibration facility consisting of a free-falling water column was also designed and built. Results of the calibrations are presented and show that the flowmeter can accurately measure transient flows up to the ...


Acoustic Properties Of Soybeans, Manjit K. Misra, B. Koerner, A. Pate, C. P. Burger Mar 1990

Acoustic Properties Of Soybeans, Manjit K. Misra, B. Koerner, A. Pate, C. P. Burger

Agricultural and Biosystems Engineering Publications

Acoustic transmission and impact force response methods were investigated for classification of soybeans. The transmission method was slow and not suitable for real-time application. A polynomial was fitted to the deconvolved frequency spectrum of acoustic impulse data for soybeans. The curve fitting procedure successfully predicted the mass of each soybean. The size of soybeans was related to the bandwidth. Diseased soybeans consistently showed narrower bandwidths than healthy soybeans. The diseased and damaged soybeans had broad variations in low frequency which was quantifiable by threshholding the error of fit in the curve fitting procedure.


Ultrasonic Measurement Of The Geometric Parameters Of Gaseous Voids In Low Gravity Fluid Containers, A. T. Patten, William W. Durgin Jan 1990

Ultrasonic Measurement Of The Geometric Parameters Of Gaseous Voids In Low Gravity Fluid Containers, A. T. Patten, William W. Durgin

Office of the Provost and Vice President of Academic Affairs Scholarship

A demonstration system for the ultrasonic gauging of fluids in low-gravity has been designed and tested. For purposes of simplification, it was assumed that vapor within a liquid container in low-gravity would form a spherical bubble which would float freely in the container. The project was designed to show that ultrasonic techniques could be used to determine the geometry of the resulting sphere given a worst-case transducer arrangement. The motivation was to simplify transducer mounting requirements so that propellant or other storage vessels could be fitted with ultrasonic gauging systems with a single or perhaps a few transducer penetrations. Data ...


Evolving Towards Theory Of Constraint-Based Manufacturing Planning And Control Systems, James W. Wagner Jan 1990

Evolving Towards Theory Of Constraint-Based Manufacturing Planning And Control Systems, James W. Wagner

Theses and Dissertations

No abstract provided.


A Holistic Approach To Design From Conception Through Retirement, Mark William Hammond Jan 1990

A Holistic Approach To Design From Conception Through Retirement, Mark William Hammond

Theses and Dissertations

No abstract provided.


An Approach For Designing Protective Capacity Based On The Tradeoffs Between "Work-In-Process", "Manufacturing Lead Time", And "Capacity", Ashish Masih Jan 1990

An Approach For Designing Protective Capacity Based On The Tradeoffs Between "Work-In-Process", "Manufacturing Lead Time", And "Capacity", Ashish Masih

Theses and Dissertations

No abstract provided.


Control Of Multi-Stage Manufacturing Systems, Simon Raban Jan 1990

Control Of Multi-Stage Manufacturing Systems, Simon Raban

Theses and Dissertations

No abstract provided.


Analysis Of The Effect Of Buffer Storage In Production Systems, Bala Ramakrishnan Jan 1990

Analysis Of The Effect Of Buffer Storage In Production Systems, Bala Ramakrishnan

Theses and Dissertations

No abstract provided.


Surface Mount Device Technology :, Udey Chaudhry Jan 1990

Surface Mount Device Technology :, Udey Chaudhry

Theses and Dissertations

No abstract provided.