Engineering Science and Materials Commons^™

Case Studies: In-Situ Rebuilding Of Damaged Rope Drum Shafts Of Ssg Crane And The Repair Of Circumferential Crack Of Cement Kiln By Welding, Joseph Runyoro

Tanzania Journal of Engineering and Technology (TJET)

Material failures in engineering are characterized by unwanted downtime of equipment and require the application of sound engineering principles to rectify the problem so that it does not reoccur. The most widely method for repairing damaged steel structures such as rope drum shaft or cracked cement kiln is by Manual metal arc welding. The equipment mentioned have their main importance that, when they are broken down, they cost a lot of money in lost revenue and affects a lot of people in terms of business and livelihood. The nominal diameter (DN) 240 rope drum shaft was damaged when the roller …

Method Of Transferring Strained Semiconductor Structure, Michael Nastasi

Department of Mechanical and Materials Engineering: Faculty Publications

The transfer of strained semiconductor layers from one substrate to another substrate involves depositing a multilayer structure on a substrate having surface contaminants. An interface that includes the contaminants if formed in between the deposited layer and the substrate. Hydrogen atoms are introduced into the structure and allowed to diffuse to the interface. Afterward, the deposited multilayer structure is bonded to a second substrate and is separated away at the interface, which results in transferring a multilayer structure from one substrate at least one strained semiconductor layer and at least one strain-induced seed layer. The strain-induced seed layer can be …

A Use Of Theory Of Constraints Thinking Processes For Improvements In The Merged Beams Experiment At Oak Ridge National Laboratory., Bryan Richard Gross

Electronic Theses and Dissertations

Thinking exercises used in the Theory of Constraints (TOC) were used to find and remove constraints at the Merged Beams Experiment at Oak Ridge National Laboratory. The goal of this project was to significantly reduce the amount of time used to take a certain type of measurement during an experimental cycle. After the TOC exercises were used, a basic plan for change was discovered. Preliminary data were taken to establish a baseline of performance from which changes were made. Post-Modification was analyzed showing the project was a success.

The overlying reasoning for this exercise was to prove successfully that continuous …

College Of Engineering Senior Design Competition Fall 2009, University Of Nevada, Las Vegas

Fred and Harriet Cox Senior Design Competition Projects

Each student in his or her senior year chooses, plans, designs, and prototypes a product in this required element of the curriculum. The senior design project encourages the student to use everything learned in the engineering program to create a practical, real-world solution to an engineering challenge.

A highlight of the year-long senior design project is the senior design competition. This competition, which usually takes place the week before finals each semester, helps focus the senior students on increasing the quality and potential for commercial application for their design projects.

Judges from local industry evaluate the projects on innovation, commercial …

Effects On Digital Image Quality When Photographing Through A Transparent Material Used To Hold Or Flatten An Original Object, Paul E. Howell

Masters Theses

An increasing number of libraries and archives are initiating projects where new and updated technologies make it practical to digitize materials containing color and fine detail. Many of the imaging systems and methods used for this process require that some type of glass or plastic be placed over the original to hold it flat and in the correct position during image capture. The physical properties of a material placed between an original object and the capture system or camera, during digitization, could possibly affect the accuracy of image color and quality being reproduced by the system. This investigation provides an …

Design, Reconstruction And Evaluation Of A Dynamometer For Quarter Scale, Samuel Sanchez

BioResource and Agricultural Engineering

This project discusses the design, reconstruction, and evaluation of a dynamometer. A new test stand for the Quarter Scale team would improve the testing of the engines and the Continuously Variable Transmission (CVT). All the readings will be done electronically in order to provide the most accurate data collection. The dynamometer will be a closed hydraulic system for ease of use. This system will be able to test all of Quarter Scale engines. The data collected will be used to determine which engines are in the best condition, and which may need to be fixed. With the new design, the …

Vibrations Of Thin Plate With Piezoelectric Actuator: Theory And Experiments, Parikshit Mehta

All Theses

Vibrations of flexible structures have been an important engineering study owing to its both deprecating and complimentary traits. These flexible structures are generally modeled as strings, bars, shafts and beams (one dimensional), membranes and plate (two dimensional) or shell (three dimensional). Structures in many engineering applications, such as building floors, aircraft wings, automobile hoods or pressure vessel end-caps, can be modeled as plates. Undesirable vibrations of any of these engineering structures can lead to catastrophic results. It is important to know the fundamental frequencies of these structures in response to simple or complex excitations or boundary conditions.
After their discovery …

User Study Of Information Extracted From Engineering Representations, Rachel Hannah

All Theses

It is important for designers to understand the usefulness of different engineering representations in order to save time and money throughout a project. Designers often rely on past experience to decide which model to construct; yet students without this experience have no help. Interestingly there are noticeable gaps in the research literature with respect to how and when to select representations and modeling approaches for engineering designs. This thesis examines the differences between three types of engineering representations, specifically sketches, drawing packages, and physical prototypes. The amount of information designers can extract from these representations and also the correctness and …

Modeling The Cooling Phase Of The Lens Molding Process, Saravanan Kannan

All Theses

The lens molding process is a relatively new technique used to manufacture lenses, in particular, high precision aspheric lenses. In order to achieve the desired size and shape of the lens, the cooling process after pressing must be controlled precisely because of the time and temperature dependent viscoelastic behavior of glass near and below the molding temperature. This thesis gives a detailed description of a three-dimensional computational model for analyzing the cooling phase of the lens molding process. Conduction, convection and radiation are considered in the model by coupling a computational fluid dynamics analysis of the flow of nitrogen through …

Robust Parameter Design And Finite Element Analysis For A Non-Pneumatic Tire With Low Vibration, Amarnath Proddaturi

All Theses

During rolling of a non-pneumatic tire, vibration may be produced by the interaction of collapsible spokes with a shear deformable ring as they enter the contact region, buckle and then snap back into a state of tension. Other potential sources of vibration include the interaction of tire tread with the ground and ring vibration. In the present work, a systematic study of the effects of key geometric design parameters is presented using Taguchi's Robust Parameter Design Method and Orthogonal Arrays.
In the present work, a 2D planar finite element model with geometric non-linearity and explicit time-stepping is used to simulate …

Relationships Between Lane Change Performance And Open-Loop Handling Metrics, Robert Powell

All Theses

This work deals with the question of relating open-loop handling metrics to driver-in-the-loop performance (closed-loop). The goal is to allow manufacturers to reduce cost and time associated with vehicle handling development. A vehicle model was built in the CarSim environment using kinematics and compliance, geometrical, and flat track tire data. This model was then compared and validated to testing done at Michelin's Laurens Proving Grounds using open-loop handling metrics. The open-loop tests conducted for model validation were an understeer test and swept sine or random steer test. Four commonly used handling metrics (steady state yaw rate gain, yaw rate damping …

Me-Em Enewsbrief, December 2009, Department Of Mechanical Engineering-Engineering Mechanics, Michigan Technological University

Department of Mechanical and Aerospace Engineering eNewsBrief

No abstract provided.

Linguistic Analysis Of Natural Language Engineering Requirements, Carl Lamar

All Theses

In engineering design, the needs of the customer are expressed through engineering requirement statements. These requirement statements are often expressed using natural language because they are easily created and read. However, there are several problems associated with natural language requirements including but not limited to ambiguity, incompleteness, understandability, testability and over specificity. Several representation and analysis tools have been proposed to address these problems within a requirement statement. These tools include formal languages, such as UML and SysML, requirement management tools, such as IBM Telelogic Doors, and natural language processors such as QuARS. These tools assist in the systematic elicitation …

Principal Component Thermography For Steady Thermal Perturbation Scenarios, Rohit Parvataneni

All Theses

The work focuses on the qualitative enhancement of Thermographic Inspection data using Principal Component Analysis technique. A new processing tool named Economical Singular Value Decomposition (SVD) is proposed for analyzing the infrared image sequences acquired from the test specimen.
Experiments are carried out on test sample using thermal excitation modalities such as flash, halogen and induction to create temperature variations. The infrared (IR) image sequence containing the information about the sample is captured using IR cameras. The acquired IR image sequences are processed using the proposed Economical SVD which projects the matrix of raw pixel values of image sequence into …

Experimental Characterization Of Stress Relaxation In Glass, Hemanth Kadali

All Theses

Glass viscoelasticity has gained importance in recent years as glass lens molding appeared as a valuable alternative to the traditional grinding and polishing process for manufacturing glass lenses. In the precision lens molding process, knowledge of viscoelastic properties of glass in the transition region, which affect the stress relaxation behavior, is required to precisely predict the final size and shape of molded lenses. The purpose of this study is to establish a step-by-step procedure for characterizing the viscoelastic behavior of glass in the glass transition region using a finite term Prony series of a Generalized Maxwell model. This study focuses …

Charging Kinetics Of Electric Double Layer Capacitors, Clint Cagle

All Theses

A recent increase in the popularity of EDLCs and AC-EOF has necessitated a deeper understanding of the structure and charging kinetics of electrical double layers (EDLs) at electrode-electrolyte interfaces. Here, the charging kinetics of EDLs in nanoscale EDLCs is studied by a circuit model, a Poisson-Nernst-Planck (PNP) mo del, and molecular dynamics (MD) simulations. The results of the MD simulations demonstrate a linear charging behavior of EDLs near planar electrodes for both aqueous and organic electrolytes at charging below 90% and time larger than tens of picoseconds. Additionally, we will show that the circuit and PNP models are capable of …

Design And Analysis Of Alternating Spoke Pair Concepts For A Non-Pneumatic Tire With Reduced Vibration At High Speed Rolling, Shashank Bezgam

All Theses

Recently, Michelin has invented an innovative non-pneumatic tire which has potential for improved handling, grip, comfort, and less rolling resistance when compared to a traditional pneumatic tire. The non-pneumatic wheel is manufactured from a molding process with integrated shear ring and collapsible spokes designed to provide optimal uniform ground contact patch with low rolling resistance. The shear band is constructed from a polyurethane material with imbedded inextensible reinforcements. During high speed rolling in initial testing, the original prototype showed high noise levels at frequencies above 100 Hz. A possible source of noise could be due to vibration initiated from the …

Monitoring Co Concentration In Fuel Cells Using Microcantilever Sensors, Tugba Demir

All Theses

Estimating the concentration of gases including carbon monoxide (CO) in the hydrogen fuel exiting the reformer and entering the fuel cell is imperative. A high concentration of CO can cause fuel-cell catalyst poisoning, which permanently destroys the cell. Current practices call for utilizing expensive and bulky spectral analyzers to achieve this task. In addition to their high cost, these methodologies, undoubtedly, hinder the portability and self-containment of the cell. To overcome these problems and achieve the desired objectives of a portable, self-contained, and real-time measurement module, this thesis presents and experimentally investigates a new enabling technology based on utilizing an …

Friction Stir Welding Process And Material Microstructure Evolution Modeling In 2000 And 5000 Series Of Aluminum Alloys, Harshavardhan Yalavarthy

All Theses

Interactions between the rotating and advancing pin-shaped tool (terminated at one end with a circular-cylindrical shoulder) with the clamped welding-plates and the associated material and heat transport during a Friction Stir Welding (FSW) process are studied computationally using a fully-coupled thermo-mechanical finite-element analysis. To surmount potential numerical problems associated with extensive mesh distortions/entanglement, an Arbitrary Lagrangian Eulerian (ALE) formulation was used which enabled adaptive re-meshing (to ensure the continuing presence of a high-quality mesh) while allowing full tracking of the material free surfaces. To demonstrate the utility of the present computational approach, the analysis is applied to the cases of …

Straight Line Braking Performance Of A Road Vehicle With Non Linear Tire Stiffness Formulation, Anup Khekare

All Theses

The capability of a road vehicle equipped with an Anti-Lock Braking System (ABS) to come to a safe stop depends on factors such as dynamic force between tire and road, surface adhesion coefficient, and the vertical profile of the road. When in panic, a driver's reaction is to step hard on the brakes to make the vehicle stop as soon as possible. Although the use of modern technologies such as ABS and Electronic Stability Control (ESC) have reduced the number of accidents significantly, any further improvement in stopping distance would only complement these technologies.
Michelin has undertaken the development of …

Evaluation Of Fluid Diodes As Pulmonary Heart Valve Replacements, Tiffany Camp

All Dissertations

Children born with congenital heart disease often times suffer from severe chronic pulmonary insufficiency. Palliative treatments for this condition may come early on in the life of the patient; however, if it becomes severe enough, a pulmonary valve replacement may be required. There currently is not a permanent option for a replacements valve. Therefore, a need exists to develop a permanent solution. Knowing that the right heart circulation is more tolerant of moderate levels of regurgitation (0 - 35%) and pressure gradient (0 - 30 mmHg), this study investigates the hypothesis that a fluid diode, a motionless valve that offers …

Dynamics Of Ultrasonic Consolidation, James Gibert

All Dissertations

Ultrasonic consolidation (UC) is a solid state rapid manufacturing process derived from ultrasonic welding of thin metal foils coupled with contour milling to achieve functional accurate components. The bonding of metal is accomplished by the local application of high frequency vibration energy under pressure producing a metallurgical bond without melting the base material. Its unique nature allows the design and fabrication of structural panels for satellites, production of injection molding tools, functionally graded structures, metal-matrix composites, embedded sensors, armor, and fiber embedded adaptive structures. It is commonly theorized that interfacial motion and friction at the bonding interface play a prominent …

The Effect Of A Surfactant Monolayer On Gas Exchange Across An Air-Water Interface During Mixed Convection, Richard Lee

All Theses

A set of laboratory experiments are presented that reveal the effect of a surfactant monolayer on the transport of oxygen across an air-water interface during mixed convection conditions. The experiments were conducted in a wind/water tunnel with water tanks of differing depth. Forced convection was imposed via the air flow, while natural convection was imposed by heating the water bulk above the air temperature. For the range of wind speeds being considered, mixed convection conditions resulted. Experiments were also conducted with only forced convection present. The data acquired during these experiments were used to develop a parameterization between the Sherwood …

Identifying The Optimum Process Parameters Of Precision Glass Molding For Aspherical Lenses, Waqas Iqbal

All Theses

The purpose of this research is to determine the optimum process parameters for the Precision Glass Molding (PGM) Process using Manufacturing Design, Design of Experiments and Metrology (for measuring the geometry of lenses). First, a custom machine is designed and manufactured which can carry out Precision Glass Lens Molding Experiments. This machine is then modified to improve temperature, position and force control. A literature review is performed to obtain data for process parameters that have been used in previous PGM studies. The collected data is then used in Design of Experiments to create twenty seven experiments that determine the optimum …

Indirect Electrosynthesis Of Double Aldehyde Starch Using Pb-(Bro3-/Br-) As Electro-Catalytic Mediator, Ni-Na Chen, Ri-Yao Chen, Xi Zheng, Xiao Chen, Zhen Chen

Journal of Electrochemistry

In this paper,Nafion membrane was used as the separator in the electrolysis cell to indirectly electro-generating the double aldehyde starch(DAS) with BrO₃^-/Br^-as a redox mediator and Pb as an anode.Effects of temperature,concentration of sulfuric acid and starch on the electro-oxidation of DAS were discussed.The steady state polarization curves were obtained.The experiment results showed that the current efficiency was over 50% when the electrolysis current density was 15mA/ cm².

Preparation Of Polyaniline/Polyester Conductive Fabric Via In-Situ Polymerization, Fang Na, Wei Wang

Journal of Electrochemistry

The formation of PANI coating on the surface of PET fiber and fabric was obtained by in-situ polymerization method.The coating′s thickness was about 1～2 μm.Orthogonal test methodology was used to analyze the main factors of preparation of PANI / PET conductive fabric.The effects of the aniline monomer concentration,oxidant: aniline molar ratio,doping acid concentration and types,reaction time on the conductivities of the fabric were studied.The structure of the polymer were characterized by SEM,FTIR and XRD.The results indicated that there was uniform and continuous polyaniline film on the surface of polyester fabric.The contents of oxidation and reduction of polyaniline molecular chain structure …

Progresses In Electrocatalysis Of Nanomaterials—Tuning The Surface Structure And Property Of Electrocatalysts, Yan-Xia Jiang, Na Tian, Zhi-You Zhou, Sheng-Pei Chen, Shi-Gang Sun

Journal of Electrochemistry

The property of an electrocatalyst depends strongly on its surface structure.The study of surface structure-catalytic functionality is the base of design and preparation of electrocatalysts of high activity,high stability and high selectivity at microstructure level.In this paper,based mainly on our results concering hydrogen and oxygen adsorption-desorption,ethylene glycol oxidation and CO₂ reduction,the research progresses in tuning the surface structure and property of electrocatalysts are summarized.This paper overviews firstly the cyclic voltammetric characteristics,electrocatalytic properties of platinum single crystal planes lying on different crystallographic zones of the unit stereographic triangle of face-centered cubic(fcc) metals.Next,the innovation of electrochemical methods to control the surface …

Electrooxidation Of Formic Acid On Pd-Ni Alloy Film Electrode-The Effect Of Dealloying, Chao Wang, Fei-Fei Shi, Jin-Yi Wang, Han-Xuan Zhang, Wen-Bin Cai

Journal of Electrochemistry

A Pd-Ni alloy film was electrodeposited on Au disc electrode at a constant potential from a weakly basic bath containing PdCl₂,NiSO₄ and ethylenediamine.The as-deposited film was then subjected to potential cycling in a perchloric acid solution for surface dealloying treatment.The dealloyed Pd-Ni film electrode was examined for the electrocatalytic oxidation of formic acid,and compared with the as-deposited one as well as a Pd film electrode.The FE-SEM and electrochemical measurements on the Pd-Ni films revealed that the dealloying treatment caused a surface roughening and an increase in specific surface reaction area.The ICP-AES and XPS analyses demonstrated that the …

Electrocatalysis In Polymer Electrolyte Membrane Fuel Cells, Li Li, Si-Guo Chen, Xue-Qiang Qi, Yao-Qiong Wang, Meng-Bo Ji, Lan-Lan Li, Zi-Dong Wei

Journal of Electrochemistry

This review presents the study of Chongqing University in electrocatalysis for polymer electrolyte membrane fuel cells(PEMFCs).Based on the understanding to the performance degradation of PEMFCs' catalysts,the university has being concentrated on how to increase the activity,stability and utility of noble metal catalysts.It covers the molecular design of near-surface alloy catalysts for improvement of activity to oxygen reduction reaction(ORR) and resistance to foreign poison species,selective deposition of Pt on the so-called "three-phase interface" for a high Pt utility,and invention of anti-flooding electrode against water flooding in the catalyst layer of the membrane assemble electrode(MEA),and so on.The catalytic mechanism of electrode reactions …

Highly Durable Pt/Ruo2/C Catalyst For The Cathode Of Direct Methanol Fuel Cells, Chun-Yu Du, Tao Dong, Ge-Ping Yin, Peng-Fei Shi

Journal of Electrochemistry

Instability of the carbon-supported Pt(Pt/C) catalyst at the cathode is one of the key technical challenges for the development of Direct Methanol Fuel Cells(DMFCs).In this paper,an efficient approach to enhancing the stability of the cathode catalyst was explored by designing and synthesizing a novel nanocomposite support,RuO₂ coated carbon black(RuO₂/C).Firstly,a wet chemical method was employed to synthesize the RuO₂/C nanocomposite,from which Pt/RuO₂/C catalyst was further prepared by a microwave method.The morphology and crystalline structure of the RuO₂/C support and Pt/RuO₂/C catalyst were then characterized by TEM and XRD.Finally,the electrochemical performance …