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1994

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Articles 1 - 30 of 167

Full-Text Articles in Mechanical Engineering

Design For Quality Manufacturability Analysis Of Missing/Misplaced Parts And Part Interference, Altaf Yusuf Tamboo Dec 1994

Design For Quality Manufacturability Analysis Of Missing/Misplaced Parts And Part Interference, Altaf Yusuf Tamboo

Theses

Design for Quality Manufacturability (DFQM) is an approach that addresses the issue of quality manufacturability (QM) - the likelihood that defects will occur during manufacture of a product in a standard plant. The DFQM methodology is based on the premise that defects found in assembled products are often influenced by some features of the design and/or assembly process (influencing factors). These influencing factors cause defects in the presence of certain error catalysts.

One of the influencing factors is geometrical features such as shape and symmetry. A classification scheme for part shape and symmetry is developed. This scheme is summarized in ...


Use Of Multiple Transmitters For 3-D Non-Intrusive Particle Tracking, Jitesh H. Agrawal Dec 1994

Use Of Multiple Transmitters For 3-D Non-Intrusive Particle Tracking, Jitesh H. Agrawal

Theses

A method for non-intrusive tracking of a particle in 3-dimensional space, based on processing of signals emitted from a transmitter embedded in the particle, is being developed. This method uses a mathematical model, which predicts the induced signal in receivers present in the vicinity of flowing particle, and supporting numerical techniques. Specific application aspects related to improving the accuracy of this method are presented.

The focus here is the development of flexible software capable of processing information coming from multiple transmitters with known distinct spatial orientation. Implementation aspects of modified existing empirical corrections for improving model-reality agreement, and new techniques ...


Viscoelastic Effects On Parallel Flow Stability, Transition To Turbulence, And Turbulent Flow, Michael Garofalo Dec 1994

Viscoelastic Effects On Parallel Flow Stability, Transition To Turbulence, And Turbulent Flow, Michael Garofalo

Theses

The classical two dimensional theory of stability of parallel flow is extended to viscoelastic fluids. How the elasticity of the fluid affects the point of stability and determines the point of transition to turbulence is analyzed. In addition the magnification of disturbances is elucidated. This study is based on a viscoelastic constitutive equation which has been successful in predicting the experimental trends of various unsteady high shear rate laminar flows. A viscoelastic stability equation which is an extension to the Orr-Sommerfeld equation for a Newtonian fluid is derived and solved for a flow between parallel plates superimposed by a two-dimensional ...


Development Of An Expert System To Facilitate A Pump Manufacturing/Warehouse Facility, Muhammad Mutahir Ghauri Dec 1994

Development Of An Expert System To Facilitate A Pump Manufacturing/Warehouse Facility, Muhammad Mutahir Ghauri

Theses

The objective of this study is to evaluate the effectiveness of utilizing an expert system technology as it relates to manufacturing. It appears that our industries are still uncertain about this technology. In the first phase of this study, procedure for deployment of this technology is discussed. Secondly a knowledge-based expert system is developed, using a VP-Expert microcomputer shell. The system is made of three modules, inventory module, cost analysis module, and decision making module (for the selection of pumps).

A warehouse was selected for the analysis, which carries the finished product in the form of pumps. The quantities and ...


Case Study Of Assembly Defects In Manufactured Products, Michael J. Withka Dec 1994

Case Study Of Assembly Defects In Manufactured Products, Michael J. Withka

Theses

Design for Quality Manufacturability (DFQM) is a design tool that empowers engineers to create designs that are easily and effectively transformed into manufactured products. The goal of this methodology is to make designers aware of design characteristics that may lead to product defects during the assembly process. Acknowledging the possibility of these defects will enable the designer to institute design modifications early in the design phase. The benefits realized in this approach are a reduction in the number of defects in the finished product, reduced product cycle times, a reduction in monitoring costs and a reduction in time-to-market.

This thesis ...


Investigation Of Velocity Distribution Within High Speed Waterjet, Hong Cao Dec 1994

Investigation Of Velocity Distribution Within High Speed Waterjet, Hong Cao

Theses

The aim of this research was to investigate velocity distribution within the water jet at different conditions of jet formation. The water jet (WJ) velocity was measured by the use of Laser Transit Anemometer (LTA) and statistical technique which improved the accuracy of the velocity determination.

The velocities were measured for different diameters of the sapphire nozzle under different water pressures at different axial stand off distances and radial distances across the jet. The experiments performed in this study enabled us to evaluate the effects and conditions of the water jet on the velocity distribution. The acquired results provide information ...


A Petri-Net Based Methodology For Modeling, Simulation, And Control Of Flexible Manufacturing Systems, Venkatesh Kurapati Dec 1994

A Petri-Net Based Methodology For Modeling, Simulation, And Control Of Flexible Manufacturing Systems, Venkatesh Kurapati

Dissertations

Global competition has made it necessary for manufacturers to introduce such advanced technologies as flexible and agile manufacturing, intelligent automation, and computer-integrated manufacturing. However, the application extent of these technologies varies from industry to industry and has met various degrees of success. One critical barrier leading to successful implementation of advanced manufacturing systems is the ever-increasing complexity in their modeling, analysis, simulation, and control. The purpose of this work is to introduce a set of Petri net-based tools and methods to address a variety of problems associated with the design and implementation of flexible manufacturing systems (FMSs). More specifically, this ...


Robust Approach To Object Recognition Through Fuzzy Clustering And Hough Transform Based Methods, Tianxiong Fu Dec 1994

Robust Approach To Object Recognition Through Fuzzy Clustering And Hough Transform Based Methods, Tianxiong Fu

Dissertations

Object detection from two dimensional intensity images as well as three dimensional range images is considered. The emphasis is on the robust detection of shapes such as cylinders, spheres, cones, and planar surfaces, typically found in mechanical and manufacturing engineering applications. Based on the analyses of different HT methods, a novel method, called the Fast Randomized Hough Transform (FRHT) is proposed. The key idea of FRHT is to divide the original image into multiple regions and apply random sampling method to map data points in the image space into the parameter space or feature space, then obtain the parameters of ...


Simulation Study Of Particle Tracking System, Prashant B. Patel Dec 1994

Simulation Study Of Particle Tracking System, Prashant B. Patel

Theses

A particle tracking system is being developed in the Particle Technology Laboratory of the Mechanical Engineering Department, at NJIT, In this thesis, an attempt is made to understand the effect of various parameters on the errors in the computed position and orientation of the sphere being tracked. Simulation results for a single transmitter assembly as well as a three transmitter assembly with 6, 9 and 17 antennae are presented. The effects of the level of noise in the voltages on the solution for the single transmitter assembly and three transmitter assembly are discussed. The concept of virtual antenna is introduced ...


Statistical And Finite Element Analysis Of The Effects Of Random Input Parameters On The Mechanical Characteristics Of Sheetmetal Forming Processes Using Quadrature Method, Yu Quan Dec 1994

Statistical And Finite Element Analysis Of The Effects Of Random Input Parameters On The Mechanical Characteristics Of Sheetmetal Forming Processes Using Quadrature Method, Yu Quan

Theses

In this thesis, the computer aided finite element analysis is implemented in the analysis of sheetmetal forming process. To rationalize the experimentation and analysis, the statistical method is introduced to study the variability of sheetmetal deformation process and final shape with respect to the variation of different parameters.

In Chapter 2, the basic characteristics and considerations of deep drawing operation is described with emphasis on the study of geometrical and physical variables of the forming process.

Chapter 3 discussed the three phases which are encountered in the computer aided finite element analysis. As a typical representative of professional finite element ...


Radiative Transfer Of Ultrasound, Joseph A. Turner, Richard L. Weaver Dec 1994

Radiative Transfer Of Ultrasound, Joseph A. Turner, Richard L. Weaver

Faculty Publications from the Department of Engineering Mechanics

A radiative transfer equation is used to model the diffuse multiple scattering of ultrasound in a medium containing discrete random scatterers. An assumption of uncorrelated phases allows one to write an equation of energy balance for the diffuse intensity. This ultrasonic radiative transfer equation contains single-scattering and propagation parameters that are calculated using the elastic wave equation. Polarization effects are included through the introduction of an elastodynamic Stokes vector which contains a longitudinal Stokes parameter and four shear Stokes parameters similar to the four Stokes parameters used in optical radiative transfer theory. The theory is applied to a statistically homogeneous ...


Radiative Transfer And Multiple Scattering Of Diffuse Ultrasound, Joseph A. Turner, Richard L. Weaver Dec 1994

Radiative Transfer And Multiple Scattering Of Diffuse Ultrasound, Joseph A. Turner, Richard L. Weaver

Faculty Publications from the Department of Engineering Mechanics

A model is presented fro the multiply scattered incoherent field in a continuous polycrystalline elastic medium. Unlike a previous development based upon energy conservation considerations [J. A. Turner and R.L. Weaver, J. Acoust. Soc. Am. 93, 2312 (A) (1993)] for a medium containing discrete random scatterers, the present model has been developed from the wave equation and first principles. Appropriate ensemble averaging of the wave equation leads to Dyson and Bethe-Salpeter equations which govern the mean Green’s function and the covariance of the Green’s function, respectively. These equations are expanded for weak heterogeneity and equations of radiative ...


An Investigation And Improvement Of Electrorheological (Er) Fluid Technology, Adil F. Dalal Dec 1994

An Investigation And Improvement Of Electrorheological (Er) Fluid Technology, Adil F. Dalal

Master's Theses

The purpose of this research was to investigate and overcome the limitations of Electrorheological (ER) fluids and to introduce this advanced technology at WMU. Electrorheological (ER) Fluids are a special class of fluids, which exhibit a reversible, infinitely variable phase transition from a liquid to a solid/semi-plastic state, in the presence of an electric field.

ER fluids can provide a unique solution to the problems of vibration isolation of systems. The applications are currently limited due to the high voltage requirements, electric power related heating and limited research into wear/abrasive characteristics of ER fluids.

A specially designed and ...


The Effects Of Non-Uniform Blade Geometries On Cascade And Turbine Stage Performance, Hiroyuki Maeda Dec 1994

The Effects Of Non-Uniform Blade Geometries On Cascade And Turbine Stage Performance, Hiroyuki Maeda

Master's Theses

It is known that in-service turbomachinery blades do not have uniform shapes. There are small differences due to blade erosion, manufacturing tolerances, or faulty installation. These differences can be in the size, shape, or relative angles of the blade. In an effort to predict losses resulting from changes in blade thickness and/or blade angles, a two-part investigation has been conducted. A two-dimensional unsteady Navier-Stokes flow analysis has been used to perform numerical experiments.

First, simulations were performed for an isolated cascade. One of the two stators was scaled and/or rotated. Results of the numerical simulations show that increasing ...


Design Of A Miniature Hydraulic Power Unit, Ryan D. Bruneau Dec 1994

Design Of A Miniature Hydraulic Power Unit, Ryan D. Bruneau

Honors Theses

The need for a newly designed miniature hydraulic power unit has received the attention of Parker-Hannifin Hydraulic Pump/Motor Division. The current power unit is no longer marketable due to the associated costs and its relative size. As a result, a miniature hydraulic power unit has been designed, the culmination to the engineering curriculum at Western Michigan University. In order to increase the overall marketability and to reduce production costs, a transparent plastic reservoir has been incorporated into the design. An appropriate polymer has been chosen to meet the design requirements and finite element analysis has been used to verify ...


The Spectral Center Of Gravity Effect And Auditory Filter Bandwidth, Marc Fagelson, Linda M. Thibodeau Nov 1994

The Spectral Center Of Gravity Effect And Auditory Filter Bandwidth, Marc Fagelson, Linda M. Thibodeau

Marc A. Fagelson

The spectral center of gravity refers to a listener’s averaging of frequency and intensity components when formant peaks in a speechlike signal are separated by 3.5 Bark units or less. In this paper a total of 18 synthetic vowels whose spectra approximated /ae/ or /inverted vee/ were generated digitally; each stimulus contained the first 40 harmonics of a 100‐Hz fundamental. Nine spectra contained three formants, while the balance contained only two. Subjects with normal hearing and mild high‐frequency hearing loss above 3000 Hz were instructed to identify synthetic vowels as either /ae/ or /inverted vee/ as ...


Minutes Friends Of Tractor Test Museum November 1994, Tractor Museum Nov 1994

Minutes Friends Of Tractor Test Museum November 1994, Tractor Museum

Museum Planning and Development Documents

Subcommittee Structure Hitchcock foundation


Improvement Of Waterjet And Abrasive Waterjet Nozzle, Zheng Li Oct 1994

Improvement Of Waterjet And Abrasive Waterjet Nozzle, Zheng Li

Dissertations

This investigation is concerned with the improvement of the nozzle design for water and abrasive water jet machining. The mechanism of formation and characteristics of pure water and abrasive water jets are investigated in order to determine quasi-optimal process conditions.

To improve the pure water jet machining, a pulsed water jet nozzle, which employs the principle of the Helmholtz type resonator, is investigated experimentally and numerically. The experiments show the advantages of this nozzle over the commercial nozzle in cutting and cleaning. A numerical solution of the differential equations of continuity, momentum conservation, turbulent kinetic energy and dissipation for two ...


Local Thermal Stress Factor Of Pipe-Nozzle, David Chihwei Chen Oct 1994

Local Thermal Stress Factor Of Pipe-Nozzle, David Chihwei Chen

Dissertations

A comprehensive study of local thermal stresses at the juncture of pipe-nozzle is presented in this thesis. The thermal loading is assumed to be a linear thermal gradient across the thickness of the pipe and nozzle. Currently, there exists neither experimental nor analytical data that is sufficient for pressure vessel designers to analyze the local thermal stresses at the juncture of pipe-nozzle. In order to provide a comprehensive database to calculate these thermal stresses, the finite element technique is used to provide a series of local thermal stress factor plots as a function of pipe-nozzle geometrical parameters.

For the local ...


Local Stress Factors Of Pipe-Nozzle Under Internal Pressure, Jih-Lian Jack Ha Oct 1994

Local Stress Factors Of Pipe-Nozzle Under Internal Pressure, Jih-Lian Jack Ha

Dissertations

This thesis presents a comprehensive study of local stresses around a pipe-nozzle due to internal pressure. The finite element method (FEM) was employed to provide a numerical solution which will furnish a database for stress analysts to compute local stresses of pipe-nozzle due to internal pressure. The local pressure stresses for both the pipe and the nozzle around the pipe-nozzle juncture are first normalized into pressure stress factors which are then plotted as functions of geometrical parameters, beta, β, (nozzle mean radius / pipe mean radius) and gamma γ, (pipe mean radius / pipe thickness). These local pressure stresses at each point ...


Model T Project Progress Report 1994, Tractor Museum Oct 1994

Model T Project Progress Report 1994, Tractor Museum

Museum Planning and Development Documents

Model T Restoration


Characterization Of The Near-Interface Region Of Chemical Vapor Deposited Diamond Films On Silicon By Backscatter Kikuchi Diffraction, Brent L. Adams, K. Kunze, S. Geier, R. Hessmer, M. Schreck, B. Rauschembach, B. Stritzker Oct 1994

Characterization Of The Near-Interface Region Of Chemical Vapor Deposited Diamond Films On Silicon By Backscatter Kikuchi Diffraction, Brent L. Adams, K. Kunze, S. Geier, R. Hessmer, M. Schreck, B. Rauschembach, B. Stritzker

Faculty Publications

The lattice orientations near the interface of chemical vapor deposited diamond films on Si(001) have been studied by orientation imaging microscopy. This technique is based on the automated analysis of electron backscatter Kikuchi diffraction patterns. The electron beam has been scanned in discrete steps over the reverse side of the diamond film after having removed the substrate. The obtained data have allowed us to determine the texture and to visualize quantitatively the orientational arrangement of and among individual diamond crystallites in the near-interface region. A comparison with the orientation of the substrate has proved the existence of epitaxially nucleated ...


Minutes Friends Of Tractor Test Museum October 1994, Tractor Museum Oct 1994

Minutes Friends Of Tractor Test Museum October 1994, Tractor Museum

Museum Planning and Development Documents

Building Lease Student Employees Ted Worral Collection


Ole Miss Engineer 1994 Oct 1994

Ole Miss Engineer 1994

The Ole Miss Engineer

No abstract provided.


Simulation Of Active Control Of Asymmetric Flows Around Slender Pointed Forebodies, Hazem Sharaf El-Din Oct 1994

Simulation Of Active Control Of Asymmetric Flows Around Slender Pointed Forebodies, Hazem Sharaf El-Din

Mechanical & Aerospace Engineering Theses & Dissertations

At high angles of attack, the flowfield over slender forebodies becomes asymmetric with substantial side force, which may exceed the available control capability. The unsteady compressible Navier-Stokes equations are used to investigate the effectiveness of different active control methods to alleviate and possibly eliminate the flow asymmetry and the subsequent side force. Although the research work focuses on active control methods, a passive control method has been investigated. The implicit, Roe flux-difference splitting, finite volume scheme is used for the numerical computations. Both locally-conical and three-dimensional solutions of the Navier-Stokes equations are obtained.

The asymmetric flow over five-degree semi-apex angle ...


Gas Flow In Micr-Channels, John C. Harley, Yufend Huang, Haim H. Bau, Jay N. Zemel Sep 1994

Gas Flow In Micr-Channels, John C. Harley, Yufend Huang, Haim H. Bau, Jay N. Zemel

Departmental Papers (MEAM)

An experimental and theoretical investigation of low Reynolds number, high subsonic Mach number, compressible gas flow in channels is presented. Nitrogen, helium, and argon gases were used. The channels were microfabricated on silicon wafers and were typically 100 μm wide, 104 μm long, and ranged in depth from 0.5 to 20 μm. The Knudsen number ranged from 10-3 to 0.4. The measured friction factor was in good agreement with theoretical predictions assuming isothermal, locally fully developed, first-order, slip flow.


Geometric Decomposition And Structural Shape Modification For Turbomachinery Blades, Brian D. Hines, James H. Oliver Sep 1994

Geometric Decomposition And Structural Shape Modification For Turbomachinery Blades, Brian D. Hines, James H. Oliver

Mechanical Engineering Conference Presentations, Papers, and Proceedings

An efficient and precise method is presented for the generation of turbomachinery blade models in nominal configuration, i.e., the "cold-shape" given the blade geometry at operating conditions, i.e., the "hot-shape." The shape correction technique has two main components: a preprocessor that generates a plate finite element model of the hot-shape geometry, and postprocessor decomposes the hot-shape blade surface model into a mean camber surface and an associated set of thickness functions. A plate finite element mesh is generated on the resulting mean camber surface. The finite element model is used as input for specialized analysis software for cold-shape ...


Visual Interaction In Acoustic-Structural Analysis Of Automobiles, Vijoy Gaddipati, Judy M. Vance, Richard Devries Sep 1994

Visual Interaction In Acoustic-Structural Analysis Of Automobiles, Vijoy Gaddipati, Judy M. Vance, Richard Devries

Mechanical Engineering Conference Presentations, Papers, and Proceedings

This paper describes a graphical technique used for investigating the effects of structural design changes on the sound pressure levels generated in an automobile compartment. Low frequency noise in the passenger compartment (in approximately the 20-85 Hz frequency range) is of primary interest, and particularly that noise which is generated by the structural vibrations of the wall panels and various other smaller parts of the compartment. A designer faced with reducing the noise levels at various frequencies typically has several hundred design variables as candidates for change. This paper describes a computer interface that facilitates understanding of the effect various ...


Parametric Volume Models For Interactive Three-Dimensional Grid Generation, Jawad D. Mokhtar, James H. Oliver Sep 1994

Parametric Volume Models For Interactive Three-Dimensional Grid Generation, Jawad D. Mokhtar, James H. Oliver

Mechanical Engineering Conference Presentations, Papers, and Proceedings

A methoid based on non-uniform rational B-spline (NURBS) curve, surface, and solid technology is presented for interactive grid generation of three-dimensional flow fields encountered in turbomachinery applications. The method allows construction of several types of mutli-block grids including H-grids for three dimensional grid generation. Automated two-dimensional block construction is facilitated via a traversal method that searches four-sided regions in the initial block structure. A NURBS surface is then constructed on each block by transfinite interpolation of the boundary curves themselves, and various point distribution options may be applied. Three-dimensional grid generation is an extension of the two-dimensional procedure. Tri-parametric hyperpatches ...


Flotation Column With Adjustable Supported Baffles, Surendra K. Kawatra, Timothy C. Eisele Aug 1994

Flotation Column With Adjustable Supported Baffles, Surendra K. Kawatra, Timothy C. Eisele

Michigan Tech Patents

An apparatus for separating by froth flotation hydro- phobic and hydrophilic particles contained in an aqueous slurry, the apparatus comprising a generally vertical tubular column having an upper froth zone, an upper separation zone, a lower separation zone, an air inlet zone, and an intermediate feed inlet zone; a feed inlet, air inlet, froth outlet and a tailings outlet; an upper baffle unit comprising a plurality of horizontally extending upper baffle plates, a vertical upper support member including an upper end portion, and first upper apparatus for removably mounting the upper baffle plates on the upper support member at predetermined ...