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1993

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Articles 1 - 30 of 322

Full-Text Articles in Mechanical Engineering

Numerical Investigation Of Flow Through Wide Angle Diffusers, Moududur Rahman Dec 1993

Numerical Investigation Of Flow Through Wide Angle Diffusers, Moududur Rahman

Dissertations

This study is aimed at the development of a computational technique for the prediction of the flow field in wide angle diffusers. The finite element technique is used for the solution of the governing equations. A commercial software package, NISA/3DFlUID, modified for this specific application was used. The parameters affecting the flow field have been identified. For a wide range of variation of these parameters, the effects on the flow field have been examined. This investigation is an exhaustive and comprehensive numerical study of diffuser flows. Such a study will result in substantial improvement in the understanding of the ...


An Investigation Of The Formation Of Turbulent Water And Abrasive Water Jets, Md. Ekramul Hasan Khan Dec 1993

An Investigation Of The Formation Of Turbulent Water And Abrasive Water Jets, Md. Ekramul Hasan Khan

Dissertations

This study is concerned with the development of a knowledge base for the selection of nozzle geometry by investigating the mechanism of formation and behaviors of water and abrasive water jets. A numerical prediction of turbulent water flow inside various nozzles is developed. The analysis is based on the numerical solution of conservation equations of continuity and momentum as well as equations of turbulent kinetic energy and dissipation for 2-dimensional axisymmetric flow by using a finite element package, FIDAP.

The technique for determining velocities and forces of water jet and abrasive water jet with the Laser Transit Anemometer and Piezoelectric ...


Computer Aided Stress Analysis Of The Femur With Prosthetic Hip Stem Utilizing Computed Tomography, Wei-Chun Chang Dec 1993

Computer Aided Stress Analysis Of The Femur With Prosthetic Hip Stem Utilizing Computed Tomography, Wei-Chun Chang

Dissertations

A computer aided design and analysis method, utilizing computed tomography (CT) is developed, which together with a finite element program determines the stress and deformation patterns in the femur with hip prosthesis. The CT scan data file provides the geometry and the material parameters for the generated finite element model. The three-dimensional finite element model of the femur with hip prosthesis is automatically generated from the CT data file by a preprocessing procedure. The preprocessor includes a CT image display, edge detector, nodes generation, prosthesis simulator, mesh generator and model display. The loading conditions applied on the finite element model ...


An Integrated Mrp And Finite Scheduling System To Derive Detailed Daily Schedules For A Manufacturing Shop, Sita D. Nathan Dec 1993

An Integrated Mrp And Finite Scheduling System To Derive Detailed Daily Schedules For A Manufacturing Shop, Sita D. Nathan

Theses

Many companies rely on Material Requirements Planning (MRP) to support their Production Scheduling and Control (PS&C) functions. Since MRP does not provide a detailed shop floor schedule, these users have to implement either a third party procedure or an internally developed procedure for shop floor controls. In this thesis we consider a class of user shops which are characterized by the following features:

  • Homogenous machines, that is all machines can produce all products.

  • Each product requires a setup, but several products may have a common setup.

  • MRP requirements are specified on a weekly basis while actual requirements are specified ...


Design Of An Autonomous Vehicle System, Fritz Gerald Momplaisir Dec 1993

Design Of An Autonomous Vehicle System, Fritz Gerald Momplaisir

Theses

With advances in electronics, mobile vehicles are becoming more and more sophisticated. The Potential applications of AGVs are numerous an range from a material handling system for the factory floor to an intelligent wheel chair for the handicapped. The design of these vehicles, however, remains a difficult task. Even when the machine is given precise information about its environment, the fact that it is never free of noise further complicate the situation. One of the goals of an AGV project is to design a robust system that will operate efficiently in the presence of different sources of noise.

The scientific ...


On Stationary And Moving Interface Cracks With Frictionless Contact In Anisotropic Bimaterials, Xiaomin Deng Dec 1993

On Stationary And Moving Interface Cracks With Frictionless Contact In Anisotropic Bimaterials, Xiaomin Deng

Faculty Publications

The asymptotic structure of near-tip fields around stationary and steadily growing interface cracks, with frictionless crack surface contact, and in anisotropic bimaterials, is analysed with the method of analytic continuation, and a complete representation of the asymptotic fields is obtained in terms of arbitrary entire functions. It is shown that when the symmetry, if any, and orientation of the anisotropic bimaterial is such that the in-plane and out-of-plane deformations can be separated from each other, the in-plane crack-tip fields will have a non-oscillatory, inverse-squared-root type stress singularity, with angular variations clearly resembling those for a classical mode II problem when ...


An Empirical Investigation Of Quality And Productivity Management Practices In Manufacturing Firms, Kiran Vuppalapati Dec 1993

An Empirical Investigation Of Quality And Productivity Management Practices In Manufacturing Firms, Kiran Vuppalapati

Master's Theses

A growing number of firms are implementing the concept of Just In Time (JlT) manufacturing and Total Quality Management (TQM). This research examines the impact of these management philosophies in manufacturing firms.

This research identifies a set of critical organizational variables necessary for a successful . implementation and the organizational problems faced during their implementation. The major object is to test the performance of firms implementing both JlT and TQM against firms implementing none of these philosophies. Results show that JIT-TQM firms are more customer focused and have better employee relations than traditional firms. This study also compares the performance of ...


An Experimental Study Into The Role Of Routing Flexibility In The Justification Of Advanced Manufacturing Systems, Sanjay Pathak Dec 1993

An Experimental Study Into The Role Of Routing Flexibility In The Justification Of Advanced Manufacturing Systems, Sanjay Pathak

Master's Theses

Increased competition in manufacturing has focused attention on advanced technologies. These costly technologies lead to difficulty in purchase justification using traditional methods. New methods quantify attributes relating to the flexibility of advanced systems. One such attribute is routing flexibility.

This thesis presents results of experiments into evaluation of routing flexibility. The performance of conventional dedicated machinery when compared with that of machines having routing flexibility indicates an advantage of flexible machinery. The thesis indicates a procedure for evaluation of different flexibilities and their comparison with conventional machinery in reality.

An empirical formula is developed that helps in quantifying routing flexibility ...


Three Dimensional Stress Intensity Factor For Large Arrays Of Radial Internal Surface Cracks In A Cylindrical Pressure Vessel, Javier Pierola Nov 1993

Three Dimensional Stress Intensity Factor For Large Arrays Of Radial Internal Surface Cracks In A Cylindrical Pressure Vessel, Javier Pierola

FIU Electronic Theses and Dissertations

The objective of this study is to present the mode I stress intensity factor distribution (SIF) along the crack-front for a wide array of semicircular and semi-elliptical surface cracks inside of a pressurized thick-walled cylinder. A three-dimensional finite element package ANSYS is used to evaluate the SIF for multicracked cylinder with number of cracks from n=1 to 128, the ratio of crack-depth to the wall thickness a/t=0.05 to 0.6, the ellipticity of the crack (the crack-depth to the semi-crack length) a/c=0.2 to 1.5, the ratio of the outer to the inner ...


Performance Assessment Of Prosthetic Heart Valves Using Orifice Area Formulae And The Energy Index Method, Flavio Ballerini Souza Campos Nov 1993

Performance Assessment Of Prosthetic Heart Valves Using Orifice Area Formulae And The Energy Index Method, Flavio Ballerini Souza Campos

FIU Electronic Theses and Dissertations

Valve function is commonly assessed by effective orifice area (EOA) estimates using equations derived from conservation of mass and energy. Errors have been found with the method due to difficulties in determining the valve’s coefficient of discharge (Cd). The Cd, a factor that corrects the EOA for losses in the valvular wake region, has been shown previously to vary with the Reynolds number and valve geometry. In this study, a Cardio-Vascular Duplicator (CVD) is used to determine the Cd for three types of mitral valves, operating in modes ranging from normal to severely stenotic. Since orifice area methods do ...


Comparison Of Suppression Across Frequencies, Linda M. Thibodeau, Marc A. Fagelson Nov 1993

Comparison Of Suppression Across Frequencies, Linda M. Thibodeau, Marc A. Fagelson

Marc A. Fagelson

Although much research has focused on the temporal, spectral, and intensity relationships between a masker and a suppressor, there has been little attention directed towards relative amounts of suppression in different frequency regions. The purpose of this experiment was to compare the magnitude of suppression at 500 and 2000 Hz in two forward‐masking experiments with seven normal‐hearing persons. In the first experiment, the threshold for a 10‐ms probe was determined as the bandwidth of a 400‐ms masker increased from 0.05 to 1.6 times the probe frequency. Suppression was determined by observing a decrease in ...


Paradigm Shift In Materials Processing - The Intelligent Processing Revolution, Diran Apelian Nov 1993

Paradigm Shift In Materials Processing - The Intelligent Processing Revolution, Diran Apelian

Mechanical Engineering Faculty Publications

During the last several decades, the importance of materials processing in the control of microstructure and materials properties has been recognized and, accordingly, the materials engineering community has dedicated much effort to studying the physics of the process. These endeavors have provided an understanding of the phenomena which are relevant. However, a paradigm shift is taking place in that the physics oriented approach to materials processing is being replaced by a control oriented approach. What is needed today is the ability to control the process and, thus, the trajectory of the controllable variables in a temporal space. Such a knowledge ...


Brittle Composites Modeling: Compazisons With Mosi2/Zro2, S.P. Chen, Richard Alan Lesar, A. D. Rollett Nov 1993

Brittle Composites Modeling: Compazisons With Mosi2/Zro2, S.P. Chen, Richard Alan Lesar, A. D. Rollett

Richard Alan Lesar

We have calculated the mechanical properties of brittle composites with spring-network (SN) model. The composites that we studied involve the transformation toughening effects and the accompanying micro-cracking. Our simulation results are consistent with experiments of MoSi2 toughened with ZrO2. By monitoring the stress changes due to the transformation and micro-cracking we are able to separate, for the first time, the contributions from these two competing effects. We also found that the fracture toughness of the composite increases as the modulus, interfacial cohesion of particle increases.


A Kinematically Intelligent Blackboard For Computer Aided Instruction, J. Keith Nisbett, D. Watkins, Clark R. Barker Nov 1993

A Kinematically Intelligent Blackboard For Computer Aided Instruction, J. Keith Nisbett, D. Watkins, Clark R. Barker

Mechanical and Aerospace Engineering Faculty Research & Creative Works

A CAI (computer-aided instruction) package is being developed to be used as a classroom tool for the instruction of undergraduate mechanical engineering students in an introductory kinematics of mechanisms course. This graphical environment allows the instructor to emulate on the projected graphics screen everything that is currently done on the blackboard for planar mechansims. Unlike the blackboard, the software will have the intelligence to interpret the drawings in a kinematic sense so that the drawing of the linkage will behave as a linkage. The software environment involves three principal components: (1) a sketching method for defining the linkage, (2) the ...


Deposition Of Particles In A Convergent Channel, Hsi-Chung Chiou Oct 1993

Deposition Of Particles In A Convergent Channel, Hsi-Chung Chiou

Dissertations

The deposition of suspensions for uniform flow in convergent channels under the combined influences of inertia, viscous, gravity and electrostatic image forces were studied theoretically. A two dimensional, steady, incompressible, laminar flow with uniform velocity profile was assumed.

It was found that when the ratio of charge parameter to gravity parameter, Q/G, is greater than 5, the deposition is dominated by the electrostatic image force alone and that the gravity effect can be neglected. When the ratio of charge parameter to gravity parameter, Q/G, is less than 0.001, the image force can then be neglected. It was ...


Set-Up Saving Schemes For Printed Circuit Boards Assembly, Oded Z. Maimon, Ezey M. Dar-El, Tali F. Carmon Oct 1993

Set-Up Saving Schemes For Printed Circuit Boards Assembly, Oded Z. Maimon, Ezey M. Dar-El, Tali F. Carmon

Industrial and Manufacturing Engineering

Focusing on a basic printed circuit board (PCB) assembly line configuration characterized by very long set-up times, we examine two scheduling methods that can significantly reduce the set-up. Both methods -the Grouped Set-Up (GSU) method that has been recently introduced in the literature and the Sequence Dependent Scheduling (SDS) method, which has not been studied in this context -are based on component commonality among PCB types. Using the typical traditional scheduling method as a benchmark, the GSU and the SDS methods are compared in terms of three performance measures: line throughput, average work-in-process (WIP) inventory level, and implementation complexity. Guidelines ...


Minutes Of Tractor Test Museum Committee October 21, 1993, Tractor Museum Oct 1993

Minutes Of Tractor Test Museum Committee October 21, 1993, Tractor Museum

Museum Planning and Development Documents

Status of using tractor test building. Organizing Friends of the Tractor Test Museum


Notes From Museum Committee Meeting October, 1993, Tractor Museum Oct 1993

Notes From Museum Committee Meeting October, 1993, Tractor Museum

Museum Planning and Development Documents

No abstract provided.


Froth Flotation Apparatus, Jiann-Yang Hwang Oct 1993

Froth Flotation Apparatus, Jiann-Yang Hwang

Michigan Tech Patents

The froth flotation apparatus includes a gas bubble-particle contact unit including a mixing structure for breaking a gas into fine bubbles,such as a packed tower packing or mechanical agitator, and a separate phase separation unit. A conditioned aqueous pulp containing a mixture of hydrophobic and hydrophilic particles and a substantially inert gas, such as air, are introduced into and combined in one end of the contact unit and subsequently flow concurrently through the mixing structure, such that the gas is broken into fine bubbles which intimately contact and become attached to the hydro- phobic particles. The resulting gas bubble-particle ...


Ole Miss Engineer 1993 Oct 1993

Ole Miss Engineer 1993

The Ole Miss Engineer

No abstract provided.


Multi-Purpose Orchard Shaker/Power Plant, Lloyd Snell Sep 1993

Multi-Purpose Orchard Shaker/Power Plant, Lloyd Snell

Lloyd D Snell

A harvesting machine for nuts and stone fruits including an articulated body with a front part and a back part. A tree shaker head is detachable and couples to the front part of the harvesting machine by a C-frame mount. The articulated body with a low clearance provides necessary maneuverability in an orchard environment, while permitting the harvesting machine with the shaker head detached, to function as a general purpose orchard machine for mowing, spraying, brush clearing and other associated tasks. Specialized machinery for these tasks is no longer necessary.


Torsional Sensor Applications In Two-Phase Fluids, Jin O. Kim, Haim H. Bau, Yi Liu, Lawrence C. Lynnworth, Steven A. Lynnworth, Kimberly A. Hall, Saul A. Jacobson, James. A. Korba, Robert J. Murphy, Michael A. Strauch, Kyle G. King Sep 1993

Torsional Sensor Applications In Two-Phase Fluids, Jin O. Kim, Haim H. Bau, Yi Liu, Lawrence C. Lynnworth, Steven A. Lynnworth, Kimberly A. Hall, Saul A. Jacobson, James. A. Korba, Robert J. Murphy, Michael A. Strauch, Kyle G. King

Departmental Papers (MEAM)

A solid corrosion-resistant torsional waveguide of diamond cross section has been developed to sense on-line and in real-time the characteristics of the liquid in which it is submerged. The sensor can measure, among other things, the liquid content of a bubbly medium; the density of adjacent pure liquids; the equivalent density of liquid-vapor mixtures or particulate suspensions; a suspension's concentration; and the liquid level. The sensor exploits the phenomenon that the speed of propagation of a torsional stress wave in a submerged waveguide with a noncircular cross section is inversely proportional to the equivalent density of the liquid in ...


Integration Of Simulation Modeling And Computer Aided Production Management In Computer Integrated Enterprise, Emine Persentili, Sema E. Alptekin Sep 1993

Integration Of Simulation Modeling And Computer Aided Production Management In Computer Integrated Enterprise, Emine Persentili, Sema E. Alptekin

Industrial and Manufacturing Engineering

Designing efficient and integrated manufacturing systems is the first step in attaining computer integrated enterprises (CIE). Integration of planning and implementation phases of manufacturing is essential for taking full advantage of the CIE. In order to design reliable and efficient manufacturing systems, the designers must consider the impacts of planning decisions made by computer aided production management (CAPM) modules on implementations held in manufacturing cells. This paper focuses on two issues. The first issue is importance and necessity of integrating CAPM modules with manufacturing cells. The second issue includes major features of the object-oriented approach and their relevance to our ...


Book Review, Suzanne B. Watson Sep 1993

Book Review, Suzanne B. Watson

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

Review of the book: HELENA SZEJNWALD BROWN, ET AL., CORPORATE ENVIRONMENTALISM IN A GLOBAL ECONOMY: SOCIETAL VALUES IN INTERNATIONAL TECHNOLOGY TRANSFER. (Quorum Books 1993) [264 pp.] Acknowledgments, bibliography, figures, index, tables. LC 92- 19851; ISBN: 0-89930-802-3. [$49.95. P.O. Box 5007, Westport CT 06881.]


An Area Presevering Transformation Algorithm For Press Forming Blank Development, Nirmal K. Nair, James H. Oliver Sep 1993

An Area Presevering Transformation Algorithm For Press Forming Blank Development, Nirmal K. Nair, James H. Oliver

Mechanical Engineering Conference Presentations, Papers, and Proceedings

An efficient algorithm is presented to determine the blank shape necessary to manufacture a surface by press forming. The technique is independent of material properties and instead uses surface geometry and an area conservation constraint to generate a geometrically feasible blank shape. The algorithm is formulated as an approximate geometric interpretation of the reversal of the forming process. The primary application for this technique are in preliminary surface design, assessment of manufacturability, and location of binder wrap. Since the algorithm exhibits linear time complexity, it is amenable to implementation as an interactive design aid. The algorithm is applied to two ...


Sculpted Surface Model Synthesis Based On Functional Design Constraints, James H. Oliver, Philip C. Theruvakattil Sep 1993

Sculpted Surface Model Synthesis Based On Functional Design Constraints, James H. Oliver, Philip C. Theruvakattil

Mechanical Engineering Conference Presentations, Papers, and Proceedings

A technique if presented for the synthesis of sculptured surface models subject to several functional design constraints. A design environment is specified as a collection of polyhedral models which represent components in the vicinity of the design surface, or regions which the surface should avoid. The primary functional constraint is formulated as a proximity penalty function such that the design surface is induced to avoid a tolerance envelope around each component. In addition, a constraint based on surface area is formulated to counteract the expansion effect of the proximity constraint. Secondary design constraints are formulated to maintain consistent surface topology ...


Approximating Eigenvalues And Eigenvectors Using Padé Approximants, Judy M. Vance, James E. Bernard Sep 1993

Approximating Eigenvalues And Eigenvectors Using Padé Approximants, Judy M. Vance, James E. Bernard

Mechanical Engineering Conference Presentations, Papers, and Proceedings

Design optimization of finite element-based structures can be very compute intensive thus inhibiting interactive design. The research presented here outlines a fast method for approximating eigenvalues and eigenvectors across a wide range of design changes. An optimization scheme is described that combines Padé Approximants with curve-fitting techniques to achieve good approximations for large design changes.


A Kalina Cycle Application For Power Generation, Mounir B. Ibrahim, Ronald M. Kovach Sep 1993

A Kalina Cycle Application For Power Generation, Mounir B. Ibrahim, Ronald M. Kovach

Mechanical Engineering Faculty Publications

A multi-component (NB3/H2O) Kalina-type cycle that utilizes the exhaust from a gas turbine is investigaed in this paper. The turbine-inlet pressure of 5.96 × 106N/m2 and temperature of 755.372 K were kept constant, as well as the working fluid temperature at the condenser outlet (at 290K). The HN3 mass fraction at the turbine inlet was varied along with the seperator temperature and the effects on the cycle efficiency were studied. The relationships between turbine-inlet flow and the seperator-inlet. How are shown in addition to the upper and lower HN3 ...


Transient Flowmeter Calibration Facility, Paul J. Lefebvre, William W. Durgin Aug 1993

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

Office of the Provost and Vice President of Academic Affairs Scholarship

An apparatus for defining the free surface of a moving column of a fluid in a vertical pipe to enhance the accuracy of measurements of transient rate of flow of the fluid using electromagnetic flowmeter is described. It provides a neutrally buoyant plug which stays in contact with the free surface of the column of the fluid at all times and thus defines the free surface of the fluid moving in the vertical pipe accurately and reduces the oscillations of the free surface of the fluid.


A Low-Dimensional Model For Chaos In Open Fluid-Flows, David J. Olinger Aug 1993

A Low-Dimensional Model For Chaos In Open Fluid-Flows, David J. Olinger

Mechanical Engineering Faculty Publications

A forced Landau-Stuart equation is studied in order to derive a low-dimensional model describing the temporal behavior of a paradigm open flow, the two-dimensional forced cylinder wake. Numerical results from the model exhibit several characteristics of circle maps, and compare qualitatively to previous experimental results for an oscillating cylinder wake. The low-dimensional model is also shown to reduce to a circle map in the limit of small forcing amplitudes. Observation of circle map dynamics in the forced Landau-Stuart equation strengthens the conjecture that globally unstable fluid flows are amenable to a dynamical systems approach focusing on the study of low-dimensional ...