Engineering Commons^™

Determination And Studying Of Stress Distribution In Various Ankle-Foot Orthoses : Experimental Stress Analysis, Rong Feng

Theses

Ankle-Foot Orthosis (AFO) is prescribed to constrain and inhibit abnormal motion such as "drop foot" due to stroke. Most orthoses were hand-made by orthotists according to their own experience. However, some types of AFO were easy to fatigue (out of their functional capabilities) than others due to regular usage. In order to improve the design and usage, quantitative stress analysis of different types of orthoses is needed. The objective of this project is to obtain experimental data which will confirm the results obtained from previous Finite Element Analysis (FEA)^[1]. In addition, the experimental analysis is extended to obtain …

Design Improvement Using Reverse Analysis In Design For Quality Manufacturability, Vikram V. Datla

Theses

The competitive needs of modern manufacturing demands that innovative approaches be used to gain an edge over the competitors. least Product design is one of the key dimensions wazzu in which companies can excel. Shortening the product design cycle so as to rapidly launch defect free products, is the goal of most companies. Design for Quality Manufacturability (DFQM) is a technique used to evaluate the quality manufacturability of a product at the design stage, so as to eliminate quality problems during production.

DFQM provides a means for relating the activities of quality improvement, product design and manufacturability analysis. The basis …

An Investigation Into The Feasibility Of Utilizing Pneumatic Ultrasonic Devices Coupled With Pneumatic Fracturing In Enhancing Removal Of Volatile Organic Compounds From Soils, Hugo J. Fernandez

Theses

A bench scale investigation was conducted in a Plexiglass ™ Test cell 1 foot square by 2 feet in height, packed with 400 mesh sand to a density of 100 lb. /ft³. The sand was contaminated with a mixture of 10% ethanol and 90% water by weight having a total weight of 11.1 pounds, before it was packed in the test cell. A geotextile 1/2 inch thick was used as a simulated fracture and was placed 3 inches from the bottom of the tank. A siren and a whistle were tested in this fracture.

The data were divided …

Low Frequency Characterization Of A Loop Antenna, Irene Koukhta

Theses

The conventional solution of an integral equation for the loop antenna in free space can be expressed analytically using Fourier Series. However, the solutions based on delta gap feed model yield divergent input susceptance.

To overcome such diverging results, alternative solution using equivalent magnetic frill current feed models were implemented. Although low frequency models for delta gap feeds were suggested, no generalized low frequency expansions for the input admittance have been reported previously. In this work, such generalized low frequency expansion are developed for both delta-gap and magnetic frill feeds of loop antennas. Validity of such expansion have been investigated …

Mechanical Evaluation Of Pedicle Screw Fixation Of The Lumbar Spine, Ding Lu

Theses

Pedicle screw fixation of the lumbar spine has been reported to increase fusion rates A biomechanical evaluation of four different pedicle screw implant systems, (AO. Rogozinski, TSRH and Wiltse). was performed to compare intrinsic device stiffness under conditions of flexion-compression and forty-five degree off-axis flexion-compression The effect on stiffness of the loosening of device members was also studied. Testing was done in load control using an electrohvdrualic testing machine. UHMWPe blocks are used to simulate the vertebra.

Assuming that stiffness is directly proportional to the probability of obtaining fusion. this study allows the ranking of the systems tested in their …

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. …

Analysis Of Surface Texture Parameters And Cutting Forces In Milling Operations, Preetesh U. Munshi

Theses

It has been known and understood that milling is quite a complicated process being a multi-point cutting tool operation. Each Surface texture is complex and requires different functions of forces to get the optimized Surface Texture. The challenge faced here is to devise any form of relation between the Surface Texture and the Milling Operating parameters (Spindle Speed, Feed rate, Depth of Cut), Cutting forces and the Milling Operating parameters and also between the Surface Texture and the Cutting Forces.

This Research study was conducted to determine the effect of the Operating Parameters on Surface Texture and Cutting forces and …

The Relationship Between Thermoregulatory And Haemodynamic Responses Of The Skin To Relaxation And Stress, Paul O. Nketia

Theses

The present study investigated the effects of stress and relaxation on (1) EEG coherence and (2) peripheral blood flow.

EEG coherence of two meditators in two different but adjacent rooms was measured during eyes opened, eyes closed, single meditation and group meditation. The skin temperatures of the subjects together with their room temperatures were also recorded. EEG coherence plots (Cospar) showed a spread out of the alpha band to the beta, theta and occasionally to the delta wave bands during group meditation. The area above the 0.98 coherence threshold in the alpha band was greater during group meditation than during …

Petri Net Modeling And Performance Analysis Of Z39.50 Search And Retrieval Protocol, Roopali Paranjpe

Theses

Z39.50 is an American Standard for information retrieval. The standard depicts a client-server model of computing. With reference to the Open System Interconnection (COSI)) model developed by International Standards Organization (ISO); Z39.50 is an application layer protocol. A Z39.50 client performs searching, querying and requesting functions and a Z39.50 server interfaces with the database in the remote system and responds to client requests by providing a set of records for the search query.

Z39.50 state tables describe a complex set of concurrent and serial events. A Petri net model is prepared for the entire system comprising the protocol. A Petri …

Low Pressure Chemical Vapor Deposition Of Silicon Carbonitride Films From Tri(Dimethylamino) Silane, Rajive Shah

Theses

A literature study to investigate the incorporation of silicon into SiC and Si₃N₄ films from various organosilanes was carried out. The Arrhenius activation energy for the synthesis of silicon, silicon carbide and silicon nitride films from various organosilanes range from 165-210 kJ/mol. A review of recent studies have indicated that silicon deposition is the rate determining step in the synthesis of silicon from silane. It is proposed here that this hypothesis can be established for the synthesis of silicon carbide, silicon nitride and silicon carbonitride film. Limited experiments indicated that the silicon deposition is a rate determining …

Decontamination Of Aquifers Via Air Sparging/Biofiltration : An Experimental Study, Armando Mora Tellez

Theses

In this study experiments were performed in order to show feasibility of an integrated air sparging/biofiltration process for cleaning contaminated groundwater. Feasibility was also meant in the sense of meeting regulatory constraints. Using toluene as model compound and changing flowrates for the sparged air, it was shown that despite fluctuations in the toluene concentration at the inlet of the biofilter, the concentrations at the outlet of the unit were essentially constant over long periods of time and remained below the levels dictated by environmental regulations. However an increase in outlet concentrations at levels not meeting regulatory constraints was observed after …

Computer Simulation Of Cerebrovascular Circulation : Assessment Of Intracranial Hemodynamics During Induction Of Anesthesia, Steven D. Wolk

Theses

The purpose of this project was to develop a computer model of cerebrovascular hemodynamics interacting with a pharmacokinetic drug model to examine the effects of various stimuli during anesthesia on cerebral blood flow and intracranial pressure.

The mathematical model of intracranial hemodynamics is a seven compartment constant volume system. A series of resistances relate blood and cerebrospinal fluid fluxes to pressure gradients between compartments. Arterial, venous, and tissue compliance are also included. Autoregulation is modeled by transmural pressure dependent arterial-arteriolar resistance. The effect of a drug (thiopental) on cerebrovascular circulation was simulated by a variable arteriolar-capillary resistance. Thiopental concentration, in …

A Cost Model For Multi-Lifecycle Engineering Design, Bin Zhang

Theses

Design for Environment aims to yield a product whose aggregate environmental impact is as small as possible. This thesis characterizes a product recovery system and defines the concepts of product lifetime and part lifetime. A multi-lifecycle product recovery model is developed based on the concepts of product tree and disassembly path representation, four product recovery choices, time varying costs, cost comparison. The four product recovery choices of a part in the product tree are: Reconditioning, Part Remanufacturing, Material Recycling, and Landfill. This thesis focuses on how to improve the product design while minimizing environmental impact of the product and introduces …

Potential Effects Of Pneumatic Fracturing On Existing Structures And Utilities, Michael C. Canino

Theses

This thesis develops a mathematical design model for predicting ground deformations resulting from pneumatic fracturing. Pneumatic fracturing is a patented process developed for the purpose of enhancing the in situ treatment and removal of hazardous contaminants from geologic formations. During pneumatic injections, measurable ground deformations are experienced both during and after the process. Safe application of pneumatic fracturing to contaminated plumes occurring beneath existing structures and utilities requires that the elastic deformation behavior of the geologic formation and overlying structures be quantified.

Data from five pneumatic fracturing sites were regressed to establish the characteristic polynomial describing the curvature of ground …

Three-Dimensional Stress Analysis Of The Femur With Prosthetic Hip Stem Utilizing Computed Tomography Scans Of The Femur For Geometry And Material Properties, Thomas J. Lavin

Theses

Three-dimensional finite element stress analyses of the femur with prosthesis hip stem were performed for two cases, one male and one female, using ideally bonded cemented titanium prostheses. Computed tomography data files were used to derive the three-dimensional femur geometry and material properties for each cortical bone element. The maximum shear stress (4.7 MPa) in the cement was greater then the maximum tensile stress and occurred at the cement-bone interface. The tensile stresses in the cement were less then the fatigue strength of the cement. The stress patterns were quite similar for the two cases.

A data analysis program was …

Optimization Of Ion-Exchange Chromotography With Multiple Gradient Inputs For Protein Separations, Tariq Mahmood

Theses

Gradient elution chromatography is an efficient technique for adjusting the retention of sample components during liquid chromatographic separations. However, the optimization of gradient elution is usually done by trial and error. Thus, for large scale processes this results in expensive and time consuming design and operations. Peak resolution that describes the degree of separation is a commonly used parameter for chromatographic processes. However, in processes where operating time and product dilution are of great importance, resolution alone is not adequate for describing the separation efficiency.

A new parameter "resolution optimization factor" is used for the optimization of gradient elution processes. …

Synthesis And Characterization Of Silicon Dioxide Thin Films By Low Pressure Chemical Vapor Deposition, Sutham Niyomwas

Theses

Ditertiarybutylsilane ( DTBS ) and oxygen have been used as precursors to produce silicon dioxide films by low pressure chemical vapor deposition. These films were synthesized in the temperature range of 600°C to 800°C at constant pressure, and at different gas flow composition. The films were found to be uniform with a composition that varied with deposition temperature and gas flow ratio. The growth rate was found to follow an Arrhenius behavior with an apparent activation energy of 2.62 kcal/mol. The growth rate was seen to increase with higher distance between wafers and to vary as a function of square …

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 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 …

Tcp/Ip Traffic Over Atm Network With Abr Flow And Congestion Control, Liping An

Theses

Most traffics over the existing ATM network are generated by applications running over TCP/IP protocol stack. In the near future, the success of ATM technology will depend largely on how well it supports the huge legacy of existing TCP/IP applications.

In this thesis, we study and compare the performance of TCP/IP traffic running on different rate based ABR flow control algorithms such as EFCI, ERICA and FMMRA by extensive simulations. Infinite source-end traffic behavior is chosen to represent, FTP application running on TCP/IP. Background VBR traffic with different ON-OFF frequency is introduced to produce transient network states as well as …

A Student Training Manual For Running The Hysim Computer Simulation Program, Roberta Rosty

Theses

Hyprotech's HYSIM computer simulation program is used in the chemical processing industry (CPI) to simulate unit operations, which aid in the design of various different kinds of processing plants. It is important then that chemical engineering students should gain early exposure to a simulation program such as HYSIM, in order to facilitate their comprehension of process engineering design work using this type of program, and to bridge the gap between the textbook knowledge they gain of unit operations in the classroom with some of the actual process engineering work-a-day methods available for solving problems.

The objective of this work was …

Measuring The Need For Manufacturing Flexibility And Evaluating Its Economic Benefits, Navin Karwande

Theses

Flexible systems are known of enabling organizations to take advantage of diversified products, low volume production items with short life-cycles. They also improve the ability to respond to market changes. Flexibility has thus become a strategic manufacturing need in recent years.

Because of the high initial capital outlay involved, the selection of the appropriate flexible solution has become a critical issue. This thesis proposes a methodology to determine the most cost effective and feasible flexibility strategy. A flexibility audit is developed to analyze and evaluate the changes taking place in a facility's environment. These changes and a measurement scheme is …

A Methodology For The Design Of An Integrated Air Stripping/Biofiltration Process To Clean Contaminated Aquifers, Pothitos Ioannis Stamatiadis

Theses

This thesis deals with the conceptual design of an integrated air stripping/biofiltration process for cleaning aquifers contaminated with volatile organic pollutants. In this technology, the pollutant is transferred from the aquifer to an air stream which is subsequently treated in a biofilter. The work presented here is an effort to develop a design methodology for the integrated process and suggests a general, quantitative approach which can be used in preliminary technology evaluation. This methodology involves relatively simple equations for the stripping process and detailed (oftentimes complex) models for biofiltration under conditions of continuous variation of the properties of the polluted …

Microporous Silicon Dioxide/Vycor Membranes For Gas Separation, Justin R. Barone

Theses

This study focused on producing membranes for molecular sieving of gases by reducing the pore size of an already existing membrane structure. To do this, SiO₂ was deposited inside the pores of a Vycor tube with initial pore diameter of 4 nm. The film deposition took place by a low pressure chemical vapor deposition (LPCVD) process where diethylsilane (DES) and nitrous oxide (N₂O) were used as precursor gases. A counterflow reactant geometry was used where the precursor gases were flowed on both sides of the porous membrane. This deposition geometry gave higher selectivities and better mechanical stability. …

Trifluoroiodomethane As An Environmentally Friendly Gas For Water Patterning By Plasma Etching Process, Krit Aryusook

Theses

Trifluoroiodomethane (CF₃I), a non-global warming gas, has been investigated with study as a substitute for typical CFC etchants, such as CF₄ and C₂F₆, used in wafer pattering technology. This investigation was carried out by exposing dielectric films of silicon oxide (SiO₂) and silicon nitride (Si₃N₄) in CF₃I and C₂F₆/O₂ (used as a reference) plasma environments. The etch rate of these films was ascertained as function of applied rf power, etchant gas flow rate, reaction chamber operating pressure, and O_{2 …}

Design Of A Mode Of Delivery For Macrobead Transplantation, Jagdip Desai

Theses

The macrobead is a form of a biohybrid artificial pancreas (BAP), which is being developed to treat type 1 diabetes. A hypothetical human transplant would require 125 rat equivalent macrobeads. For intraperitoneal transplantation a mode of delivery that allows the placement of several hundred macrobeads into a basket or pouch type device is required.

In this study, four commercially available materials were studied as possible candidates for creating a pouch. These materials are polyvinyl chloride acrylic copolymer (PVC), polyethersulfone (PES), polyvinylidenedifluoride (PVDF), and polytetrafluorethylene (PTFE). Tubular pouches of each material were designed. They then underwent in vivo biocompatibility and in-vitro …

Vibration Control Of Robotic Modules Using Input Shaping Algorithm, Murat Eren

Theses

In this thesis, vibration control using input shaping algorithm is studied. Vibration Control of flexible structures is an important problem and has been an active research area. Different approaches have been developed for vibration control which can be divided roughly into feedback and feedforward methods. Feedback methods need measurements and on-line calculation of the controller outputs. Although feedback methods are generally more robust and have a number of well known performance advantages, proper use of feedforward control can also significantly improve the speed of response of the system.

Input shaping is one of these feedforward methods. It has been successfully …

Design, Simulation And Fabrication Of A Mems In-Situ Contactless Sensor To Detect Plasma Induced Damage During Reactive Ion Etching, Subramanian Ganesh

Theses

The present trend in the semiconductor industry is towards submicron devices. An inevitable process technique in achieving this is by reactive ion etching of the polysilicon gate. During RIE, the gate oxide may get damaged due to several causes. One of the main causes of the damage is the non-uniformity of the plasma. It is reported that these plasma inconsistencies are mainly due to electrode design and that they create spatial plasma potential fluctuation. These fluctuations are reported to be in the range of 10-20 Volts. By providing an in-situ monitoring of the wafers, the reliability of the device could …

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 …

Synthesis And Characterization Of Hafnium Carbide Thin Films, Wiriya Thongruang

Theses

Hafnium carbide thin films of various characteristics were deposited on silicon substrates using dc magnetron sputtering. A HfC target was used as a sputtering source and Ar was used as a sputtering gas during deposition. The variables investigated were total sputtering gas pressure and power. Optimum characteristics were achieved with a total sputtering gas pressure of 5 mTorr and power of 200 W. No evidence for oxidation of the film was found at a depth below 400A for deposited and annealed films. Binding characteristics were obtained from ESCA data. The compressive film stress increased when sputtering gas pressure decreased. The …