Digital Commons Network^™

Experimental Studies And Modeling Of Mechanical Properties And Morphologies Of In Situ Polymer Composites, Zhigang Li

Dissertations

In this study, a series of experiments was set up in order to analyze the morphology development and mechanical properties of poly(ethylene terephthalate) (PET)/ liquid crystalline polymer (LCP) blends. Simulations of the injection molded blends at various process conditions were performed using CMOLD. In order to determine the effect of the processing parameters on the deformation of the LCP domains during the injection molding, a new analytical method to analyze the melt flow in the advancing melt front (AMF) region was developed. By combining the simulations of the injection molding and analysis of the melt flow in the AMF region, …

General Parallel-Leg Mechanism : Position Analysis, Hans Buus Gangwar

Theses

This thesis proposes to analytically express the positions of the legs (each leg has a length and two spin orientations) for a parallel leg mechanism in terms of a single variable. The only limitations imposed are the leg bases are all on the same reference plane and the tool orientation is normal to the mobile upper plate. This is done for a parallel leg mechanism having any number of legs. The variable chosen is the first leg's vertex position on the upper plate.

The state space is the space the configuration can occupy. By looking at a planar slice of …

Segregation And Flow Characterization In Vibrated Hopper, Thottiam P. Ravichandran

Theses

Experiments and numerical simulation studies were carried. out on vertically vibrated wedge-type hoppers containing binary mixtures for the present research. The studies focussed on segregation analysis of the hopper discharge and the characterization of flow pattern of the binary mixtures in sealed hoppers, over wide ranges of frequency and amplitude of acceleration to determine the effect of these parameters.

The results of segregation study show that vibration promotes segregation of the binary mixtures. However, increase in frequency was found to make the contents of segregated discharge more uniform. Also, increase in wedge angle seemed to help in reducing segregation.

The …

Interventions Of Water Jet Technology On Skin Surgery, Kittipat Vichyavichien

Theses

The perfect and precise surgical cut, similar to today's laser one, is very important in many surgeries, especially in dissection and to recanaize arterial occlusive lessions. Causing no coagulation is one of the advantages of water jet because it generates no heat. It also provides omni-directional cutting capabilities at very high speeds, resulting edge quality that is usually superior to other existing conventional cutting processes. Debris is always carried away from incisions by jet stream and less damaged tissue, than mechanical incisions. In addition, water jet exerts minimal contact pressure on the tissue being cut due to the small diameter …

Biomechanical Study Of Performance Of A Plugged Femoral Implant Coupled With A Trochanter Cable System Using Finite Element Analysis, Deanna Yvonne Carstarphen

Theses

A Finite Element Analysis was conducted to determine the effect of a plug on the performance of the critical section of a femoral implant coupled with a trochanter cable grip system. The critical section was defined near the proximal end of the stem where a hole was designed for the purpose of attaching the cable grip system. Two models were generated for the analysis. One consisted of the critical section with the grip cables and a plug filled in the hole and the other was without the plug. The models were based on design specifications provided by Howmedica Incorporated. Two …

Development Of Icejet Machining Technology, Dimitri V. Shishkin

Theses

This work was concerned with the application of ice powder for material processing. Material cutting and surface cleaning were also studied. As a result, innovative cleaning and etching technology was pioneered. The corresponding technology was designed and demonstrated.

The study involved investigation of water freezing, crushing of generated ice, ice transportation, formation of ice water and ice air streams and, finally, use of this stream for material cutting and cleaning. The theoretical work included investigation of the phase change in water and ice formation, effect of ice temperature on particles behavior and entrainment of ice particles by the water stream. …

Investigation Of Thermal Contact Resistance At A Plastic-Metal Interface In Injection Molding, Lakshminarayanan Sridhar

Dissertations

Thermal contact resistance (TCR) at the plastic-metal interface is one of the parameters required for the simulation of plastic processing techniques such as injection molding. However, the available data is both unreliable and insufficient due to the difficulties involved in measuring this parameter. The effects of thermal contact resistance on the heat transfer in plastics processing with particular reference to injection molding of thermoplastics is investigated using combined experimental measurement techniques, parametric studies and numerical analysis.

TCR under steady state conditions has been determined experimentally at typical thermoplastic-mold metal interfaces for an amorphous and a semi-crystalline polymer using a one-dimensional …

Evaluation Of Rotating Fluidized Bed As A Dry Coater, William Christopher Dunphy

Theses

Coating of particles is normally carried out with the use of environmentally unfriendly solvents. Development of dry coating methods is therefore quite important.

A Rotating Fluidized Bed was constructed, instrumented and verified as to operation. Twelve coating experiments were carried out with PMMA 200μm mean diameter as host and alumina 0.25μm primary particle size as guest with the RFB being operated in the fully fluidized range.

In all analyzed samples, coating was observed. Analysis was carried out on the qualitative basis by SEM and EDX.

An Investigation Of Polyethylene Bearing Wear Of New Jersey Lcs Knee On Cobalt Chromium And Titanium Nitride Types, Lei Wang

Theses

The total knee replacement systems (TKRS) are used for the treatment of osteoarthritis and rheumatoid arthritis. Excessive wear can substantially shorten their life span.

Two tests were performed to examine the wear characteristics of tibial bearings used in TKRS. Each test consisted of six sets of Anterior/Posterior Glide Tibial Bearings each with a conical control arm. The tibial bearings were all made by UHMWPE. Three of these bearings were mounted onto a Co-Cr alloy tibial platform and Co-Cr alloy LCS® femoral component. Another three sets of bearings were mounted onto a TiN tibial platform and TiN LCS® femoral component. They …

System Simulation And Modeling Of Electronics Demanufacturing Facilities, Ketan Giridhar Limaye

Theses

Over the last decade, pressure on the electronic industry has been increasing as concerns for product take-back, product stewardship and global warming have continued to grow. Various end-of-life management options are being expanded including recycling to recapture values from basic materials through reengineering and recovery of subassemblies and individual components for remanufacturing. While progress has been reported on life cycle assessment (LCA), disassembly planning, design for disassembly, and design for environment (DFE), very little research has been focused on demanufacturing from a systems perspective.

The objective of this thesis is to build an interface between the user who knows the …

Tools For The Design Of Flexible Manufacturind Systems, Prashant A. Patel

Theses

Flexibility in manufacturing systems can broaden the horizons for a company. But the means for achieving it are far more critical. This trend is created by the increase in competitiveness, growth of technology along with demand variations, more customization, and short product life cycles. But "Flexible Manufacturing Systems" to most of the manufacturers sounds like a synonym for automation.

A real Flexible Manufacturing System is designed when every unit of the company is synchronized in such a way to respond in a harmony to any changes that come against it. Fine-tuning of each and every part of the company is …

Object Oriented 3d Dynamic Simulation Of Flow Of Material Through Hopper, Krishnendu Roy

Theses

Development of object oriented 3D dynamic simulation of the particle is considered. This code is based on the soft sphere model dealing with both normal force , tangential force and the friction. The development of such a model and the code is motivated by the need to understand the flow patterns of granular material. The prime effort while developing this code was focused on the data encapsulation and secured access to all the attributes of all physical parameters of the bulk solid, which might be endangered by the random access of the interface of the software. A dynamically bound array …

Analytical And Experimental Study Of Investment Casting With Laser Stereolithography Models, Wen-Long Yao

Dissertations

This dissertation presents an analytical and experimental investigation of ceramic shell cracking during the burnout process in investment casting with internally webbed laser stereolithography (SLA) patterns. Included in the consideration are the cracking temperature of the ceramic shell, the web link buckling temperature, and the glass transition temperature of the epoxy resin. The hypothesis is that shell cracking will occur when the cracking temperature is lower than the glass transition temperature and the web buckling temperature.

An analytical and experimental study has been conducted, with the cross-sectional area, the span length of the web structure, and the shell thickness being …

Automobile Air Bag Inflation System Using Pressurized Carbon Dioxide, Bart Adams

Dissertations

A novel air bag inflator based on the evaporation ofliquefied carbon dioxide was developed. A detailed qualitative model wasestablished on the basis of an extensive experimental study. An integratedquantitative model of this inflator was constructed.

The system was studied by discharging the inflatorinto a tank and measuring pressure and temperature evolution (0-50 ms). Thedispersion of the two-phase spray duringinflation was investigated by high-speed cinematography.

The optimal storage pressure of the liquid CO₂was found to be 2000 psig (at 22 °C). Two distinct inflator behaviors wereidentified. First, at conditions corresponding to an initial entropy below the critical point, atwo-phase …

Robust Fuzzyclustering For Object Recognition And Classification Of Relational Data, Sumit Sen

Dissertations

Prototype based fuzzy clustering algorithms have unique ability to partition the data while detecting multiple clusters simultaneously. However since real data is often contaminated with noise, the clustering methods need to be made robust to be useful in practice. This dissertation focuses on robust detection of multiple clusters from noisy range images for object recognition. Dave's noise clustering (NC) method has been shown to make prototype-based fuzzy clustering techniques robust. In this work, NC is generalized and the new NC membership is shown to be a product of fuzzy c-means (FCM) membership and robust M-estimator weight (or possibilistic membership). Thus …

Design Of An Effective And Timely Product Development Process For Medical Devices, Jean Benoit Almonor

Theses

Effective product development process is one of the most critical issues facing medical devices manufacturing today. There is a need to search for ways to improve or solve the cross organization and company boundaries to enhance the faster release of new medical products to the market. This thesis presents an integrated set of perspectives on the process of new product development of medical devices with dual goals of achieving marketing speed and meet customer satisfaction.

The Attribute Driven Specifications approach described in this thesis, is one of the most valuable tools in the approach to effective product development in medical …

Demanufacturing Metrics For Industrial Fasteners And Disassembly Process, Narendra P. Raj

Theses

As the society progresses towards ecological maturity, the issue of reducing the environmental burden imposed by used products becomes increasingly important Environmental issues are becoming increasingly relevant for product designers and manufacturers. Public awareness of the value and fragility of an intact ecology is constantly growing, and the traditional assumption that the cost of ecological burdens to be shared by a society, as a whole is no longer accepted. Environmental protection legislation requiring manufacturers to "take back" and recycle used products will be a commonplace throughout Europe and the U.S. in the near future.

Demanufacturing involves separating and disassembling a …

Numerical Study Of Three-Dimensional Free Convection From Semi-Enclosed Geometry And Discontinuous Heat Sources, Aklilu T.G. Giorges

Dissertations

Three-dimensional natural convection from three-by-three array of isoflux heat sources mounted on one vertical wall of semi-enclosed region has been numerically investigated. Detailed thermal information of this important engineering configuration is currently not available. The major objective of this study was to obtain this needed thermal and velocity information.

The semi-enclosed geometry can be viewed as a thin rectangular region with four closed and two open sides. The open surfaces are located at the top and adjacent side. For the fluid air, Pr = 0.71, the study covered a heat flux based Rayleigh number (Ra) range of (10² ≤ …

Dynamic Friction Measurement, Modeling, And Compensation For Precise Motion Control, Simon Cohn

Theses

In this thesis, measurements of dynamic friction in a hydrodynamic journal bearing were performed for varying sinusoidal velocity excitations, loads, and lubricants. The results indicate that the friction data displays a negative slope in the mixed region of friction vs. velocity (f-v) curves, and also shows that the dynamic friction is not just a function of current velocity, but also a function of velocity history (hysteresis). These results are in agreement with previous experimental investigations by other investigators in lubricated friction.

Secondly, a dynamic friction model is fully explored and partially extended to provide quantitative agreement to measured friction values. …

Optimal Synthesis Of A Planar Four-Bar Function Generator Based On Imderect Measure Of Structural Error, Robert Ellis

Theses

A novel technique for optimal synthesis of a planar four-bar function generator is presented. An indirect measure of structural error is used to formulate an objective function which, along with its derivatives, is straightforward to evaluate and results in an elegant and robust algorithm. Lagrange multipliers are used to incorporate the loop closure constraint into the objective function.

In this thesis, the formulation of the objective function and the minimization algorithm are described, examples are presented, and the virtues and shortcomings of the algorithm are discussed.

Parameter Optimization For Curl Distortion In Building Parts Using 3-D Laser Stereolithography, Laurel A. Hanesian

Theses

The curl distortions in rapid prototyping using 3-D laser stereo lithography occur as the top layers shrink after being drawn and attaching to the bottom layers. The amount of curl is dependent upon the how much shrinkage the layer has finished prior to adhesion. It is also dependent on how deep the cure of the top layer amounts to as it adheres into the bottom layer. This thesis investigated the effect of build parameters on the distortions associated with the diagnostic 'Letter-H' shaped test part. The same parameters were also considered in a time optimization study, using calculated, predicted results …

Kinematic Analysis Of A Swash-Plate Mechanism Using Transformation Matrices, David Edgar Evans

Theses

The swash-plate mechanism is used to transfer rotational motion into translational motion and vice versa. Using transformation matrices to describe each joint, the displacements of the swash-plate mechanism were analyzed. The general transformation matrix model for the plane joint, not previously developed using transformation matrices, was presented. The solution was tested using a computer program. Examples of three different swash-plate angles; 10, 45, and 25' were considered. The solution was found to agree with previous solutions while offering a more complete description of the mechanism. Future work in this area could include a complete static, velocity, and/or dynamic analysis of …

Automobile Air Bag Inflation System Based On Fast Combustion Reaction, Yacoob Tabani

Dissertations

Current automobile air bag inflator technology is complex, expensive and environmentally unsafe. A new and novel air bag inflator based on fast combustion reactions of methane-oxygen mixtures has been developed and studied. The thermodynamics and mass flow parameters of this new inflator have been modeled and found to be in agreement with experimental results.

The performance of the fast combustion inflator was evaluated in terms of pressure-time relationships inside the inflator and in a receiving tank simulating an air bag as well as the temperature-time relationship in the tank.

In order to develop this fast combustion inflator, several critical issues …

Electrocatalytic Control Of Exhaust Soot, Victor L. Callahan

Dissertations

The feasibility of combining electrostatic precipitation and use of a catalytic wall in a straight tube reactor as a means of destroying soot particles was investigated. Enhanced particle diffusion to the wall by an applied electric field provided the means of particle capture for subsequent catalytic oxidation at the active surface in a small length tube.

Soot particles flowing in a gas stream are influenced by the following transport mechanisms: convective flux as a result of bulk flow, diffusion flux as a result of particle concentration or number density gradient, and an electrostatic flux from the coulombic attraction as charged …

Modeling Of Deformed Swept Volumes With Sde And Its Applications To Nc Simulation And Verification, Feng Lu

Theses

Representation of swept volumes has important applications in NC simulation and verification as well as robot-motion planning. Most research on .the representation of swept volumes has been limited to rigid objects. In this study, a sweep deferential equation (SDE) approach is presented for the representation of deformed swept volumes generated by flexible objects.

The deformed swept volume analysis is integrated with machining physics to account for tool deformation/deflection for the NC simulation. End milling is modeled and analyzed and the tool deformations are calculated and integrated with the SDE program. A program is developed in C++ for the generation of …

Computational Determination Of Laminar Flow Loss Coefficients In 90° Channel Bend, Leonard Paul Parkin

Theses

Loss coefficients for laminar two dimensional incompressible channel (or duct) flow in a 90° bend are investigated using FEM software, FIDAP. This problem consists of a two dimensional duct with a 90° bend of constant radius flowing with water, at 70°F and atmositeno conditions. The bend radius to duct width ratios examined were 1.5 and 1.0. Both bend radius to duct width ratios were analyzed for Reynolds Number ranging from 50 to 1800. The pressure and velocity distributions were found and used to determine the pressure due to the bend. The results show the pressure loss effect due to the …

Mechanical Design Of An Experimental Parallel Robot, Philip Song

Theses

OSCAR, or Operational Space Controlled Adjustable Robot, is a parallel-actuated manipulator, also known as Stewart Platform or platform manipulator. The apparatus consists of two platforms (base and top) and six prismatic actuators in between. The main advantage of a platform manipulator is the fact that it can out-perform serial manipulators in both load capacity and precision. However, there are disadvantages and weaknesses such as limited mobility. A platform manipulator has reduced workspace compared to serial manipulators. The problem of limited workspace is solved by enabling OSCAR to change its prismatic leg positioning about the base platform.

During the course of …

Multi-Lifecycle Assessment Of Cathode Ray Tubes, Devendra Jayant Badwe

Theses

Over the past few years environmental issues and concerns have become more and more important, as they become a common part of most people's personal experience. In these regards, the electronics industry is facing substantial problems in terms of end-of-life management of its products, televisions and monitors in particular. The building blocks of this industry are usually viewed as relatively "clean". However, manufacturing by-products of the electronics industry and the disposition of electronics are becoming increasingly important technical, financial, and environmental issues.

Within the context of the above issues, environmentally responsible disposal of Cathode Ray Tubes (CRT's), which is still …

Particle Deposition From Turbulent Flow In A Divergent Channel, Wai-Ting Huang

Dissertations

This dissertation presents a numerical analysis of particle deposition from a dilute gas-solid two-phase suspension in a divergent channel. The Lagrangian governing equations for particle motion include inertia force, viscous force, gravity force and image force from electrostatic charge on the particle. The incompressible two-dimensional turbulent flow field in a divergent channel is solved by employing a Κ-ε modeling technique with FIDAP finite element CFD software. A computational procedure is developed to incorporate the flow field into numerical simulation of particle trajectories from which the fraction of deposition is determined. Several divergent channels (half divergent angles of 0°, 7.5°, 10° …

Modeling Of 3d Swept Volumes Using Sde/Sede Methods And Its Application To Five-Axis Nc Machining, Liping Wang

Dissertations

This research falls in two important areas in solid modeling and manufacturing automation: (1) swept-volume modeling; (2) computer-based NC (Numerically controled) machining simulation and verification. The swept volume is defined as the volume swept by an object undergoing an arbitrary motion. Modeling of 3D swept volumes includes the boundary computation and representation of a swept volume generated by a general object undergoing general motion in three dimensional space. The Sweep Differential Equation (SDE) and Sweep Envelope Differential Equation (SEDE) methods are two of the important swept volume modeling methods employed in this dissertation. They exploit differential equations to obtain the …