Engineering Commons^™

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 …

Superplastic Forming System Design, Keith Bain

Honors Capstone Projects and Theses

No abstract provided.

Scaleable Stagnation-Flow Reactors For Uniform Materials Deposition: Application To Combustion Synthesis Of Diamond, K. F. Mccarty, E. Meeks, R. J. Kee, Andrew E. Lutz

All Faculty Articles - School of Engineering and Computer Science

We describe two inherently scaleable geometries for chemical-vapor- deposition and heat-transfer processes that are based on stagnation flows. The "coflow" and "trumpet-bell" designs result in radially uniform fluxes to surfaces and they optimize the use of reagents. Using a trumpet-bell burner, we have grown uniform films of diamond from a substrate-stabilized flat flame of C2H2/H2/O2.

Primary Coolant Flow Characteristics As It Exits The Palisades Reactor, Gregory Alan Baustian

Masters Theses

During fuel cycles 9 and 10 at the Palisades Nuclear Power Plant, new phenomena have been observed using the resistance temperature devices installed in the reactor coolant piping. Oscillations in the temperature readings have been observed leading to the assumptions that there is temperature stratification of the coolant in the reactor hot-legs and that the coolant rotates as it leaves the reactor. In addition, oscillations in the bulk coolant flow within the two hot legs have been postulated. This report outlines work performed using computational fluid dynamics modelling which predict the observed and assumed flow characteristics of the Palisades reactor …

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

Masters 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 …

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

Masters 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 …

Binaural Room Simulation, Brian A. Smith

Theses and Dissertations

Research in binaural and spatial hearing is of particular interest to the Air Force. Applications in cockpit communication, target recognition, and aircraft navigation are being explored. This thesis examines human auditory localization cues and develops a mathematical model for the transfer function of a sound signal traveling from an isotropic point source through a rectangular room to both ears of a listener. Using this model as a guide, non-head coupled binaural sound signals are generated in a binaural room simulation. Reflection and attenuation cues included in the computer generated signals are varied in order to determine which cues enhance the …

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 radius r_o/ r_i=2. …

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 not …

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

Marc A. Fagelson

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

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

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 also observed that …

Vibratory Size Segregation Of Particulate Matter, Anthony La Rosa

Theses

Size segregation imposed by vibration or shaking is an ubiquitous phenomenon whereby a large particle will rise to the top of a bed of smaller spheres upon vibration. Several mechanisms based on computer simulations have been proposed, however a complete theory remains elusive. The objective of this study was to perform experiments to study vibratory segregation of particles for varying size ratios and vibration parameters. More specifically, the rise time of a sphere from the bottom to the top of a vibrated bed was examined. It was found that the rise time decreased with an increase in amplitude for fixed …

Local Stress Factors Of Pipe-Nozzle Due To Radial Load, Circumferential And Longitudinal Moments, Junyu Lin

Theses

This thesis presents a series of stress factor data which provide more detailed information for the calculation of local stresses at the nozzle region, as well as the pipe region, of a pipe-nozzle intersection, subjected to an external radial load, circumferential bending moment, and longitudinal bending moment, respectively.

The pipe and nozzle thicknesses are assumed to be identical. Numerical solutions are obtained through the use of the finite element method. In obtaining the numerical solutions via ANSYS, the quadrilateral element is used to simulate the thin shell pipe-nozzle geometries. The local stresses, at eight different points on both the pipe …

Evaluation Of Collision Properties Of Spheres Using High-Speed Video Analysis, Jian Yu

Theses

Experimental evaluation of the collision properties of spheres is performed using video image analysis techniques. A high-speed Kodak EktaPro1000 video camera is utilized to record a collision sequence between two spheres at 1000 frames/sec, and then the images are analyzed to calculate three dimensional translation and rotation before and after the collision. These quantities are used to compute the collision properties for a pair of one inch nylon spheres, i.e. the coefficient of friction, and the coefficients of normal and tangential restitution. The focus of the thesis is on image analysis techniques that provide high accuracy results even though the …

Experimental Investigation Of Submerged, Turbulent, Axisymmetric Air Jet Impinging On A Flat Plate, Lan Xiao

Theses

Experimental investigation was carried out on the flow characteristics of a circular, submerged, turbulent, axisymmetric air jet impinging normally on a smooth, flat, square, Lucite plate and a sand paper covered plate. Jet issuing from a circular nozzle of 0.5 inch diameter while the Reynolds Number varying from 10,000 to 85,000 was investigated. The flow can be considered incompressible since the pressure and the velocity of the jet were not too high, with Mach Number of the order of 0.3.

Various flow parameters were measured to obtain the velocity and pressure distributions at the surface of the flat Lucite plate, …

Detection Of Planar Facets In Noisy Range Images, Ajey S. Atre

Theses

Segmentation of the image is one of the major tasks of a machine vision system designed for constructing a three-dimensional representation of the object being imaged. A robust approach for segmenting planar surfaces from range images is presented in this paper. An algorithm based on clustering through fuzzy covariance matrices, which has been proposed by Gustafson and Kessel is considered for planar segmentation. However this algorithm performs poorly if the data is noisy, which is usually the case in real life applications. In order to handle noisy data, a robust modification, based on the "noise clustering" concept, is introduced to …

Performance Of The Stirling Cycle Thermal Regenerator, Cesar A. Cravo

Theses

Most of the methods developed to analyze the performance of regenerators make assumptions which are not valid in Stirling cycle regenerators. To more adequately describe the conditions of an actual Stirling cycle regenerator a more complex method has been investigated. This method takes into account the time dependence of the mass flow and pressure fluctuations and considers the temperature dependence of the thermophysical properties.

The solution is accomplished by finite difference techniques. The solution determines the temperature distributions of the gas and matrix along the length of the regenerator and calculates the effectiveness over a cycle. A wide range of …

Processing And Application Of Polyolefin Plastics, Muhammad Khalid

Theses

This thesis describes the manufacturing, processing and application of polyolefin thermoplastics. Polyolefins have become one of the most important kinds of plastics. Polyolefin resin represents about one third of all plastics sold and its application for films and containers dominate the packaging industry. The objective of this thesis is to present the various processing methods and application of polyolefin thermoplastics. Polyolefin is produced by several different processes. Conventional low density polyethylene is made by polymerizing ethylene at high pressure and high temperatures while high density polyethylene is polymerized at relatively low pressure and low temperatures. Generally all polyolefin possess excellent …

An Application Of Neural Networks To Statistical Process Control, Asterios Papaikonomou

Theses

Recent changes in the past World War II economy have produced a more educated, value driven customer. A global economy has emerged to technological advances which has made competition fierce as well as proximate. As a result, manufacturing companies are required to provide consumers with quality products at a reasonable cost. A quality product is defined as one that fulfills the needs and expectations of the consumer and provides him with a sense of value.

Since all companies want to provide quality products, the reason why poor quality is sometimes the result is not the outcome of actions for that …

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

Lester F. Larsen Tractor 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

Lester F. Larsen Tractor Museum: Planning and Development Documents

No abstract provided.

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 mixture …

Statistical, Random And Fractal Characterizations Of Surface Topography With Engineering Applications, Gongyao Zhou

Dissertations

Two methods, namely the conventional and fractal geometry methods, are developed for surface topography characterization. The conventional method utilizing statistical and random process techniques is used to study waterjet machined surfaces. In the study the waterjet surfaces are separated into smooth and striation zones, where striation influence is negligible in the smooth zone. It is found that the smooth zone has a random, moderately isotropic texture, with the height distribution nearly Gaussian. In the striation zone the major frequencies of the surface profile power spectra are independent of cutting parameters, while the amplitudes of these frequencies monotonically increase with cutting …

Ole Miss Engineer 1993

Ole Miss Engineer

No abstract provided.

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.

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

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.]