Digital Commons Network^™

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 …

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 …

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 …

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 …

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 …

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 …

The Fatigue Problems Of Cracks Subjected To Obliquely Incident Stress Waves, I-Chung Weng

Dissertations

Catastrophic failure of aircraft and other structures are often caused by undetected cracks. Fracture mechanics has been developed to augment traditional static and fatigue design. In the static theory of fracture mechanics, extensive treatment has been given to the stress distribution around sharp cracks and notches under various loading conditions. Previous works on the problems of dynamic loadings are not accurate in dealing with singularities at high frequencies. The numerical solutions become unrealistic at high frequencies in many practical applications.

To address the need to obtain the stress intensity factor in high frequency dynamic loading situations, we studied the use …

Finite Element Analysis Of Skin Injuries By Water Jet Cutting, Syed Muhammad Arif

Theses

High pressure water jets are used in industry for cleaning and cutting purposes. These devices can generate pressure up to 400 MPa. As high pressure water jets become more widespread in industry, injuries will be seen with great frequency. Penetrating injuries by these devices can produce minimal external evidence of extensive soft tissue injury. To know the extent of injury, it is important to study the relationship between operating parameters of water jet and the skin layers. A computational analysis is carried out using finite element method to find the effects of water jet pressure on the skin layer. Finite …

Heat Transfer Enhancement From A Heat Pipe Immersed Horizontally In Water, Under Natural Convection Conditions, With The Aid Of Gas Injection, Evangelos J. Minakas

Theses

An experimental study has been performed to estimate the degree of heat transfer enhancement from a horizontal heat pipe, immersed in water with the aid of air injection. This thesis investigates the effects of different shroud shapes, shroud distances from the heat pipe, air injection rates, air injection configurations and air injection distances on the augmentation of heat transfer. Water was the experimental fluid and its temperature ranged from 17-60 °C, the surface temperature of the heat pipes varied from 18-75 °C.

It was discovered that the shape of the shrouds is a contributing factor on the heat transfer enhancement. …

Equivalent Circuit Analysis Of A Seventh Order Bandpass Loudspeaker System, Michael Gunnar Johnson

Theses

A seventh order bandpass loudspeaker system was designed using an equivalent circuit analysis. The electrical, mechanical and acoustic systems were each modeled as separate subcircuits derived by using a Voltage-Force-Pressure or impedance analogy; the interactions between the subcircuits were modeled using coupled controlled-sources. The equivalent circuit was analyzed using SPICE (Simulation Program with Integrated Circuit Emphasis). A technique for modeling port and cavity resonances inside the enclosure using distributed element approximations for the resonant components was developed and verified by measurement.

A complete microcomputer based experimental loudspeaker testing system was designed incorporating a sweep frequency oscillator, a gain-controlled audio power …

Parameters' Analysis Of 3d Random Stacking Palletization, Najeeb Syed

Theses

Palletization is a very important element of production, distribution and warehousing activities. The 3D random stacking palletization method is based on volume utilization instead of surface area optimization. Random stacking provides interlocking among the boxes and hence it improves the stability of the pallet load. Volumetric Pallet Utilization is normally the prime concern of any palletization process, with Work in Process and Palletization time being also important. This research uses data generated from a previous heuristic to establish mathematical relationships between the three mentioned performance indices and also three additional indirect variables, namely: Total Number of Sub Volumes, Partitioned Remaining …

Analytical Solutions Of Openings Formed By Intersection Of A Cylindrical Shell And An Oblique Nozzle Under Internal Pressure, Hengming Cai

Dissertations

Since several decades ago, many authors have published their research results about local stress distributions of shells and shell-nozzles both analytically and numerically. However, there has not been a published paper, which deals with analytical solutions of cylindrical shell and oblique nozzle, even though in the case of openings formed by intersection of a cylindrical shell and an oblique nozzle.

A comprehensive analytical study of local stress factors at the area of openings formed by intersection of a cylindrical shell and an oblique nozzle under internal pressure is presented in this dissertation.

By means of traditional approach in theory of …

Shaped Charges Having A Porous Tungsten Liner-An Experimental And Theoretical Study Of Metal Compression, Jet Formation And Penetration Mechanics, Brian Edward Fuchs

Dissertations

The use of porous tungsten as a liner for shaped charges to improve their penetration was proposed by Ki-Hwan Oh in his invention disclosure "Shock Extrusion of Ingots from Powders or Solids", at the New Mexico Institute of Mining and Technology, Socorro NM on June 7, 1988. The intention was to increase the ductility of the normally brittle metal by heating the liner to a high temperature by shock compaction during its acceleration just before jet formation.

The feasibility of increasing the ductility of tungsten in this way is the subject of the present study. The theory and prior experimental …

Modeling Of Objects Using Planar Facets In Noisy Range Images, Girish Phansalkar

Theses

Products designed and manufactured before the advent of Computer Aided Design (CAD) and Computer Aided Manufacturing (CAM) technology have not been documented electronically. To avoid the laborious procedure of redesigning the parts, a reverse engineering approach can be adopted. This approach involves, taking a picture of the object and constructing a solid model from the image data.

Range image is a three dimensional image of an object or a scene. This image can be obtained from special cameras, called range image cameras, or can be constructed from the Coordinate Measuring Machine's (CMM) output data. Adaptive Fuzzy c-Elliptotype (AFC) clustering algorithm …

Experimental Investigation Of Collisional Properties Of Spheres, Laurent Labous

Theses

We present experimental results on the collisional properties of spheres obtained through high-speed video analysis. An apparatus is built that produces collisions of spheres of various sizes with a wide range of impact, velocities and incidence angles.

Edge detection techniques are implemented to track the position of the spheres from frame to frame whereby the translational velocities may be computed. In order to determine the rotational velocities, small markers are imprinted on the surfaces of the spheres and also tracked and matched from one frame to the next.. From the pre and post collision kinematic data, three collisional properties are …

Experimental Study Of The Rise Of A Large Sphere In A Vibrated Bed Of Monodisperse Spheres, Loic Vanel

Theses

As a simplified way to study size segregation mechanisms, the rise of a single large sphere in a vibrated bed of smaller monodisperse spheres is investigated. The time it takes for the ball to rise from the bottom of the bed to the surface is measured in a very wide range of vibration amplitude, frequency and acceleration. Rise regimes are identified and are classified according to the macroscopic behaviors displayed by the granular bed: heaping, convection without heaping and crystallization. The influence of the large sphere's size on the rise velocity is described. The scaling features of the vibration amplitude …