Mechanical Engineering Commons^™

The Evidence For A Nascent Biotechnology Cluster In Cork, John W. Hobbs

Theses

Over the past 30 years, encouraged by Ireland’s low rate of corporation tax (currently 12.5 %), and active promotion of FDI by the IDA, foreign owned pharmaceutical plants have set up and multiplied in the Cork area. To Ireland’s advantages of a low tax rate, an English speaking population, a pro-business environment and membership of EU, Cork offered the added attractions of a deepwater port and large natural harbour, good freight connections, an international airport, an educated workforce and excellent sporting and leisure facilities for sailing, golf, etc. (Pfizer, Eli Lilly, Novartis, GlaxoSmithKline, Johnson & Johnson and Schering Plough have …

Analysis And Testing Of Waste Tire Fiber Modified Concrete, Gregory Marvin Garrick

LSU Master's Theses

There are very serious problems with the disposal of waste tires in the United States. Experiments were conducted to determine how the properties of concrete were affected by the inclusion of waste tires. Waste tires were used in the form of chips and fibers. The fibers were further divided into batches with different lengths to determine the effect of length has on the properties of concrete. There was a noticeable decline in the compressive strength of the concrete; however there was an increase in the toughness of the concrete. It was concluded that waste tire fibers were more suitable as …

Advanced Grid Stiffened Composite Structures, Dinesh Maricherla

LSU Master's Theses

In this study Advanced Grid Stiffened (AGS) composite structures are developed and analyzed for their mechanical properties. It is widely known that these structures possess light weight, high strength, and inherent impact resistance. Because of the advantages mentioned above, the AGS composite structures find many applications in aerospace, ship building and construction industries. The purpose of this study is to manufacture AGS composite structures and analyze AGS composite structures as reinforcement members. A FEA model is also developed and validated with the test results. Parametric analysis is also conducted to investigate the effects of different design parameters on these structures. …

Fracture Toughness Characterization Of Syntactic Foams, Vijay Gorugantu

LSU Master's Theses

Hollow particle filled polymeric materials called syntactic foams are used as core materials in sandwich composite structures. Syntactic foams find applications in aeronautical and space structures and therefore demand careful study and testing before they can be put to service. In the first part of this thesis work, syntactic foams are fabricated by varying the volume fraction of microballoons and also their density. Four different densities of microballoons are used ranging from 0.22 g/cc to 0.46 g/cc. The volume fraction of the microballoons is varied from 30% to 65%. A set of 3-point bending tests are conducted on these foam …

Hydrodynamic Analysis Of Compliant Journal Bearings, Amith Hanumappa Reddy

LSU Master's Theses

Compliant journal bearings are commonly used to support radial loads at extreme operating speeds and conditions where conventional bearings cannot operate. The journal and bearing system are supported by a thin lubricant film (gas) due to the hydrodynamic pressure distribution. To predict the bearing performance parameters, the compressible Reynolds equation is solved based on Infinitely Long Approximation (ILA), Finite Analysis (FA) and a new Modified Parabolic Approximation (MPA). The MPA method reduces the classical Reynolds equation to an ordinary differential equation. Appropriate equations and numerical solution are developed for treating a compressible Reynolds equation using MPA. A series of parametric …

Simulation Of A Micro Jet Cooling Array, Pierre Montanier

LSU Master's Theses

The new generation of electronic devices are more powerful, and they produce more heat. Hence, there is a need for micro cooling systems for removing the heat from these micro chips. This research focused on one micro cooling system-the micro jet cooling array. Some test simulations were made on a single jet cooling system. In addition, the inlet Reynolds number was varied in order to obtain the variation of the heat transfer coefficient. These simulations gave a basic idea of how the impingement cooling method works on the micro jet cooling array. Numerical simulations were made on the actual micro …

Effects Of Magnetic Field On Micro Flames, Sumathi Swaminathan

LSU Master's Theses

The effect of a gradient magnetic field on a diffusion micro flame i.e. C3H8/air flame has been systematically studied to comprehend their interaction. A non-uniform magnetic field was produced in the air gap of an electromagnet and the C3H8/air flame corresponding to various flow velocities was subjected to the non-uniform field. The influence of the operating conditions on the fundamental characteristics of the diffusion flame, such as the flame structure, temperature distribution and the morphology of the soot produced in these flames have been thoroughly investigated. The flame structure and its luminosity were found to be influenced and the flame …

Experimental And Numerical Study Of Feeding Channel In Proton Exchange Membrane Fuel Cell, Abul Bashar Mahmud Hasan

LSU Master's Theses

The performance of a Proton Exchange Membrane Fuel Cell (PEMFC) using different feeding configurations has been studied, with a focus on the water flooding due to electrochemical reaction. Feeding channel or Bipolar plate in Proton Exchange Fuel Cell is a dominating part. As feeding channel keeps direct contact with the gas diffusion layer, it helps efficiently supplying fuel and air into the gas diffusion layer for efficient production of electricity. Experimental data have been taken at hydrogen flow rates of 20,40,60,80,100 sccm for various bipolar plate arrangements. Three bipolar plates, namely serpentine, straight channel and interdigitated designs, were arranged in …

A Slope-Dependent Disjoining Pressure For Lennard-Jones Liquid Films, Taeil Yi

LSU Master's Theses

A molecule in a bulk liquid is subject to intermolecular forces. A molecule in a thin liquid film may experience additional intermolecular forces, if the thin film thickness h is less than roughly 100 nm. The additional forces arise from the molecule's proximity to different materials or phases sandwiching the thin film. The effect of these intermolecular forces at the continuum level is captured by disjoining pressure &Pi. Since dominates at small film thickness, it determines the stability and wettability of thin films. To leading order, Π = Π (h) because thin films are generally uniform. This form, however, can …

Electrodeposited Nanoscale Multilayers Of Invar With Copper, Diwakar Suryanarayana Iyer

LSU Master's Theses

Materials with low thermal expansion coefficients (CTEs) that will survive temperature cycling are of interest in a variety of applications on the microscale, including actuation, precision assembly, and injection mold fabrication. Invar alloys exhibit a low positive coefficient of thermal expansion ranging between 0.2 – 1.2 µm/m-°C at room temperature. The electrodeposition process for fabricating nanoscale multilayers of Invar and copper in micro-patterns was characterized to assess their value in various MEMS applications. In an ongoing effort to maintain a stable CTE and effectively control the grain growth of Invar, nano-multilayers of near Invar-like FeNiCu and copper were electrodeposited into …

Synthesis And Characterization Of Cobalt-Platinum Thin Films, Priya David

LSU Master's Theses

Co-based alloy thin films have attracted a lot of interest, due to their excellent magnetic properties, that is essential in the field of magnetic recording media. Alloying Co with metals like Pt changes some of its intrinsic magnetic properties such as increasing the magnetocrystalline anisotropy constants of the alloy. Co-Pt thin films and multilayers are more suitable for ultra high-density magnetic recording media because they have high-magnetic anisotropy, chemical stability, excellent coercivity and resistance to corrosion. In the present study, Co-Pt alloy and Pt/Co multilayered films were deposited on Si substrate using dual electron beam co-evaporation. The Co-Pt alloy thin …

Thermal Management Of The Lsu Micro Gas Chromatograph, Praveen K. Pasupuleti

LSU Master's Theses

Gas chromatography is a technique widely used for the separation and analysis of gas samples. Gas chromatographs are used for environmental maintenance, monitoring sophisticated biological analyses, and to separate components from a mixture of gases for mass spectrometer analysis. There has been a tremendous interest in miniaturization of gas chromatograph systems because of the potential for portability, faster response time, lower dead volume, lower power consumption, and lower cost of operation. Conventional gas chromatography keeps the column at a constant temperature during separation, which is called isothermal analysis. Temperature programming is a mode of gas chromatography in which the column …

Cryopreservation Of Reproductive Cells And Tissues, Guanglei Li

LSU Master's Theses

Cryopreservation of reproductive cells and tissues is a useful technique to deliver intact genomes, maximize the distribution of favorable genes, control disease spread. It is widely applied to many fields such as biology, medicine, ecology and agriculture. To optimize the cryopreservation procedure, the biophysical responses of reproductive tissues at different cooling conditions and in different mediums must be clearly understood. Here we studied the biophysical response during freezing of: 1) bovine sperm frozen at a cooling rate of 20 ˚C/min in three media: without cryopreservation agents(CPAs), with 0.7 M glycerol, and with 0.7 M glycerol along with 1.5 mg/ml of …

Study Of The Effects Of Magnetic Field On The Properties Of Combustion Synthesized Iron Oxide Nanoparticles, Nagaraju Komuravelli

LSU Master's Theses

Nanosized chain-like aggregates were developed in an iron pentacarbonyl-carbon monoxide (Fe(CO) 5 ¨C CO) air diffusion flame system. Magnetic field was applied around the diffusion flame using an electromagnet with an intensity of 0.4 Tesla. Transmission Electron Microscopy (TEM) analysis was performed to observe the behavior of the chains formed and to study the effect of magnetic field on these chains. These chain aggregates consist mainly of Fe2O3, which play a vital role in magnetic storage devices. Diffraction pattern analysis and X-ray Photon Spectroscopy (XPS) were carried out to confirm that the chain aggregates consist of mainly ¦Ã-Fe2O3. The effect …

Mesoscopic Simulation Of Grain Boundary Diffusion Creep In Inhomogeneous Microstructures, Kanishk Rastogi

LSU Master's Theses

At high temperatures, stresses well below the material’s tensile yield strength can induce permanent deformation over a period of time. This time-dependent progressive deformation of a material at constant stress is called Creep and is observed in both crystalline and non-crystalline solids. The principal deformation processes contributing to creep deformation are slip, sub-grain formation and grain-boundary sliding. Mechanisms involving creep of crystalline materials involve either dislocation motion or diffusional flow of atoms or both. Extensive studies have been done to ascertain the creep mechanism in various regimes of temperature and applied stresses. At low stresses and high temperatures, grain boundary …

Pressure-Velocity Correlation Study On 1:50 Scale Model Of The Ttu Wind Engineering Research Field Lab Building, Praveen Kumar

LSU Master's Theses

The goal of the present study is to investigate the relationship between incident wind velocity fluctuations and the surface pressure fluctuations on the roof of a low rise building. The goal was fulfilled by studying the pressure velocity correlation on 1:50 scale model of a typical low rise building, the Wind Engineering Research Field Laboratory (WERFL) building located at Texas Tech University, Lubbock. The experimental study was carried out in the LSU Wind Tunnel Laboratory by simulating the boundary layer prevalent at the full-scale site. The velocity profile in the boundary layer was measured using the TSI Hot-Wire system with …

Intrinsic Stress And High Temperature Properties Of Metal-Contanining Hydrogenated Amorphous Carbon Coatings, Bo Shi

LSU Doctoral Dissertations

A detailed examination of the intrinsic stress development and mechanical properties of titanium-containing hydrogenated amorphous carbon (Ti-C:H) and W-C:H coatings, deposited in an inductively coupled plasma (ICP) assisted hybrid chemical/physical vapor deposition (CVD/PVD) environment was carried out. Intrinsic stresses within those coatings were found to be compressive and dependent on compositions. The intrinsic compression within Ti-C:H was further shown to be significantly influenced by the energy of ionic species bombarding the substrate during growth. The results suggested that ion bombardment played a significant role in intrinsic stress generation within Ti-C:H, and was likely to influence stress development in other low …

Test 1857: Mccormick Mtx 135 Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.

Active Surgical Positioning Device For A Cochlear Implant Electrode Array, Benjamin Y. Arcand

Dissertations, Master's Theses and Master's Reports - Open

Cochlear implants have been of great benefit in restoring auditory function to individuals with profound bilateral sensorineural deafness. The implants are used to directly stimulate auditory nerves and send a signal to the brain that is then interpreted as sound. This project focuses on the development of a surgical positioning tool to accurately and effectively place an array of stimulating electrodes deep within the cochlea. This will lead to improved efficiency and performance of the stimulating electrodes, reduced surgical trauma to the cochlea, and as a result, improved overall performance to the implant recipient.

The positioning tool reported here consists …

Model Based Experimental Investigation On Powered Gait Orthosis (Pgo), Huojin Cheng

Dissertations, Master's Theses and Master's Reports - Open

Research on rehabilitation showed that appropriate and repetitive mechanical movements can help spinal cord injured individuals to restore their functional standing and walking. The objective of this paper was to achieve appropriate and repetitive joint movements and approximately normal gait through the PGO by replicating normal walking, and to minimize the energy consumption for both patients and the device. A model based experimental investigative approach is presented in this dissertation.

First, a human model was created in Ideas and human walking was simulated in Adams. The main feature of this model was the foot ground contact model, which had distributed …

Results Of An Interlaboratory Study Of The Astm Standard Test Method For Tensile Properties Of Polymer Matrix Composites D 3039, Margaret Pinnell, Richard Fields, Ronald Zabora

Mechanical and Aerospace Engineering Faculty Publications

An investigation was conducted on the ASTM Standard Test Method for Tensile Properties of Polymer Matrix Composites (D 3039). This investigation consisted of both preliminary testing and an interlaboratory test program. Information generated from preliminary testing was used to determine the effects of various parameters and to optimize the interlaboratory test plan and test protocol. The interlaboratory study portion of this investigation was conducted on six composite material systems in a variety of lay-up configurations. The number of participating labs ranged from five to nine depending on the material type. Precision statistics were determined for the ASTM D 3039 standard …

Investment Casting Using Ice Patterns -- Solid Mold And Shell Mold Methods, Harish Jose

Masters Theses

"This thesis focuses on the development and implementation of the investment casting process using ice patterns. The traditional method of the investment casting process involves using wax patterns. Wax patterns tend to expand during the dewaxing process, and this causes stress on the shell wall which can eventually lead to the breaking of the wall. Ice patterns on the other hand shrink when heated. This is a very desirable property for the investment casting process. The process of dewaxing (dewatering) of ice patterns can be achieved by keeping the shells at room temperature, instead of heating the shell in an …

Effect Of Engine Operating Conditions On The Size And Morphology Of Diesel Particulate Emissions, Adam Neer

Masters Theses

"The size, morphology and volume fraction of sub-micron particulate matter emitted from a compression ignition (diesel) engine was investigated using thermophoretic sampling experiments followed by direct visual characterizations under transmission electron microscopy. Specifically, measurements were conducted at the exhaust of a 6059T John Deere, 5.9 L, 6 cylinder, turbocharged, direct injection diesel engine. The particles observed were composed of nearly spherical primary particles (spherules) that formed aggregates of various sizes and shapes. The size distributions of spherules and aggregates were separately measured to obtain the available surface area, which is crucial for estimating the environmental and health impact of particles. …

Application Of Laser Aided Manufacturing Process For Functionally Graded Thermal Barrier Coatings, Yashodhan Joshi

Masters Theses

"Laser Aided Manufacturing Process (LAMP) is a rapid prototyping process used to build three dimensional functional metal and ceramic parts. The process developed in the LAMP laboratory at University of Missouri-Rolla uses a 5-axis fadal CNC machine and a 2.5 KW Nd:YAG (TEM₀₀) Rofin Sinar laser. The laser power and metal/ceramic powder are the input along with auxiliary systems such as shielding gas delivery, RT data acquisition, coolant system. The hybrid process makes use of metal deposition and machining to obtain parts meeting design tolerances.

LAMP is used to improve upon the process of Thermal Barrier Coating (TBC) …

Characteristics Of Laser Forming Austenitic Stainless Steel Alloys, Jack Robert Pennuto

Masters Theses

"This thesis discusses the investigation of laser forming austenitic stainless-steel alloys for the development of free curve and complex shapes...Previous work in this area has focused on the development of single angle laser forming and process optimization for the development of multi-dimensional shapes. This thesis seeks to discuss the relationship of multiple parallel laser passes and any coupling effects that may exist for the class of austenitic stainless steels, including any metallurgical implications"--Abstract, page iii.

Audio Time-Scale Modification, David Dorran

Doctoral

Audio time-scale modification is an audio effect that alters the duration of an audio signal without affecting its perceived local pitch and timbral characteristics. There are two broad categories of time-scale modifications algorithms, time-domain and frequency-domain. The computationally efficient time-domain techniques produce high quality results for single pitched signals such as speech, but do not cope well with more complex signals such as polyphonic music. The less efficient frequency-domain techniques have proven to be more robust and produce high quality results for a variety of signals; however they introduce a reverberant artefact into the output. This dissertation focuses on incorporating …

Coupled Thermal Fluid Modelling Of A Low Embedded Energy Solar Thermal Collector, Myrrha Corcoran

Theses

Flat-plate collectors are the most economical and are popular in solar domestic heating water system since they are usually permanently fixed in position, have simple construction, and require little maintenance. The design of a solar energy system is generally concerned with obtaining maximum efficiency at minimum cost. The aim of this thesis was to develop a mathematical model, for a forced convection solar heated water system. The solar collector in this study incorporated a honeycombed extruded polycarbonate structure, for both the cover and water channels.

A very detailed thermal analysis of the flat-plate solar collector was carried out to predict …

Nonlinear Control And Its Application To Active Tilting-Pad Bearings, Zhijun Cai

LSU Doctoral Dissertations

The drawbacks of active magnetic bearings are arousing interest in the adaptation of mechanical bearings for active use. A promising mechanical bearing candidate for active operation is the tilting-pad bearing. In this research, we introduce an active tilting-pad bearing with linear actuators that translate each pad. The use of feedback in determining the actuator forces allows for the automatic, continuous adjustment of the pad position during the machine operation. In this work, we develop the dynamic model of the active bearing system such that the actuator forces are the control inputs. The hydrodynamic force is modeled as a spring/damper-like force …

Physical Simulations In Classroom As A Pedagogical Tool For Enhancing Manufacturing Instruction In Engineering Technology Programs, Alok K. Verma, Han P. Bao, Anand Ghadmode, Swanand Dhayagude

Engineering Technology Faculty Publications

Lean is a powerful philosophy that advocates minimization of waste within an organization. The adoption of Lean Manufacturing philosophy by major manufacturers has created a demand for qualified personnel in this area. Higher education is not far behind in incorporating this philosophy into their curriculum. A number of universities have started offering both graduate and undergraduate courses in Lean Manufacturing. Physical simulations are often an integral part of these courses. Simulation based Lean enterprise concepts have been introduced in an undergraduate course in mechanical engineering technology program at Old Dominion University. Results show increased student participation and better understanding of …

Measurement And Control Of Torque Ripple-Induced Frame Torsional Vibration In A Surface Mount Permanent Magnet Machine, Jason Neely, Steven Pekarek, Daniel S. Stutts, Philip Beccue

Mechanical and Aerospace Engineering Faculty Research & Creative Works

A sensor to measure the stator torsional vibration due to torque ripple produced by a surface mount permanent magnet machine is first described. The sensor is relatively inexpensive and is straight forward to incorporate into a drive system. Experiments are performed to validate that the voltage produced by the sensor is linearly related to torque ripple amplitude. Closed-loop controllers are then described that adjust the stator current harmonics applied to the machine to achieve a commanded average torque while mitigating measured torsional vibration. Simulation and experimental results are used to demonstrate the effectiveness of the control techniques.