Engineering Commons^™

Effects Of Transport Properties And Flame Unsteadiness On Nitrogen Oxides Emissions From Laminar Hydrogen Jet Diffusion Flames, Doyoub Park

Electronic Theses and Dissertations

Experimental studies on the coupled effects of transport properties and unsteady fluid dynamics have been conducted on laminar, acoustically forced, hydrogen jet diffusion flames diluted by argon and helium. The primary purpose of this research is to determine how the fuel Lewis number and the flow unsteadiness play a combined role in maximum flame temperature and affect NOx emission from jet diffusion flame. The fuel Lewis number is varied by increasing/decreasing the mole fraction of diluents in the fuel stream. Therefore, maximum flame temperatures and then NOx emission levels were expected to differ for Ar- and He-diluted flames. In an …

Test 1862: Challenger Mt855b Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.

3-Dimensional Flow Measurements In Square Coaxial Jets, Thomas Lagarde

LSU Master's Theses

Results from un-forced experiments conducted in the three-dimensional flow emanating from coaxial contoured nozzles with square cross section and parallel sides are presented and discussed. Two experiments were conducted with the inner to outer jet nominal velocity ratio equal to l=0.5 and l=1.5. The Reynolds number of the outer jet based on the hydraulic diameter of the outer nozzle exit was in both cases 16,000. A multi-position hot-wire anemometry method was used for measurements in the three-dimensional turbulent flow using a dual film sensor (X-probe). A methodology was developed and implemented to derive the mean-velocity components and Reynolds stresses corrected …

An Evaluation Of Ansys Contact Elements, Serhan Sezer

LSU Master's Theses

The ANSYS code offers stress analysts a variety of contact element options: point-to-surface or surface-to-surface and low-order or high-order elements, in concert with any one of five contact algorithms (augmented Lagrangian, penalty method, etc.). This raises questions as to what option performs best under what circumstances. Here we offer some answers to these questions by examining performance in some numerical experiments. The numerical experiments focus on frictionless contact with a rigid indenter; even so, the number of experiments involved is quite large. The experiments use a battery of test problems with known analytical solutions: contact patch tests with nodes matching …

Flow And Temperature Measurements In A Linear Turbine Blade Passage With Leading Edge And Endwall Contouring And With And Without Film Cooling, Ross James Gustafson

LSU Master's Theses

Gas turbine efficiency can be improved by increasing the turbine inlet temperature. Secondary flows created in the turbine blade passage cause pressure losses and increase the thermal blade loading on the endwall, thus limiting the combustion temperature. Pressure losses, or aerodynamic losses, extract energy from the fluid, leaving less for torque or thrust production. Secondary flows also cause greater non-uniformity in the exit flow from each blade stage, which decreases the stage efficiency. Weakening secondary flows will lower pressure losses and endwall heat transfer. The following research will explore concepts for weakening the secondary flows through the use of (a) …

Simulations And Experimental Analysis Of High-Aspect-Ratio Diffusive Micro-Mixers, Amit Maha

LSU Master's Theses

Passive (diffusional) mixing has been used in designing high-aspect-ratio micro-mixers for the purpose of performing the Liagase Detection Reaction (LDR). A simple model was used to design such mixers optimized for pressure drop or time required to deliver a prescribed volume of mixture. The types of mixers considered are simple, cheap, and durable and can perform over a broad range of volumetric flow rates at reasonably modest pressure drops. The fluids typically have a very low diffusion coefficient of=1.2x10^10m^2/s, and thus diffusional mixing can only be effective in high-aspect-ratio micro-channels. A realizable aspect ratio of 6 has been considered initially …

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 …

Indium Growth On Si(100)-2 X 1 By Femtosecond Pulsed Laser Deposition, M. A. Hafez, M. S. Hegazy, H. E. Elsayed-Ali

Electrical & Computer Engineering Faculty Publications

Indium was grown on Si (100) -2×1 at room temperature by femtosecond pulsed laser deposition. Reflection high-energy electron diffraction (RHEED) was performed in situ to study film morphology and in-plane lattice spacing. Indium was found to grow on Si (100) -2×1 by the Stranski-Krastanov mode. The initial two-dimensional In layer formed in the In-2×1 structure with a lattice constant of 3.65 Å. The full-width at half-maximum (FWHM) of the specular peak decreased during the growth, indicating an increase of the In islands size. Further In growth on the initial In-2×1 layer showed the formation of hexagonal, elongated, and hemispherical islands …

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 …

Effects Of Strong Surface Energy Anisotropy On Stationary And Migrating Grain-Boundary Grooves, Donghong Min

LSU Doctoral Dissertations

Grain-boundary migration controls grain growth and is important in materials processing and synthesis. When a grain boundary ends at a free surface, a groove will develop at the tip to reduce the combined surface and grain-boundary energies. This groove may hinder the grain boundary movement and its effect needs to be understood. Previous studies have solved the groove profile for stationary or migrating grain boundaries by assuming small groove slopes with isotropic surface free energy. This work extends the analysis to finite slopes with isotropic or anisotropic surface free energy.
We first study migrating grain-boundary grooves with isotropic surface energy …

Flame Synthesis Of Carbon-Nanostructures, Saritha Perla

LSU Master's Theses

Ever since their discovery carbon nanostructures (nanotubes and nanofibers) have attracted a lot of interest, due to their striking physical, chemical, mechanical and electrical properties, and paves the path to a wide range of applications. Large quantities of these structures are necessary to make their applications viable. The challenge is to produce them in bulk and in an economical way. Current methods like Arc discharge have the disadvantages of short tube lengths, CVD generated nanomaterials are often riddled with defects and although laser ablation method produces pure and high yield of nanotubes, is a costly technique with expensive lasers and …

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 …

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 …

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.

International Partnership Using Remotely Accessed Labs, William J. Hutzel, Rudolf Furter

School of Engineering Technology Faculty Publications

An international project between the Mechanical Engineering Technology Department at Purdue University and the HVAC Engineering Department at HTA Lucerne (Switzerland) is testing the limits of the remote access concept by creating a laboratory network that is separated by thousands of miles. Using web-enabled HVAC equipment, U.S. students are determining the performance and return on investment for a heat recovery system that is physically located in Switzerland. The converse is also true, Swiss students have access to a variety of equipment located in the U.S. This remote access project is a good example of a sustainable partnership that adds an …

Advances In The Opto-Mechanical Design And Alignment Of The Hehsi Imaging Spectrometer Based On A Sagnac Interferometer, Michael Stuart Schreiber

Electronic Theses and Dissertations

The High Efficiency HyperSpectral Imager (HEHSI) is a Fourier Transform hyperspectral imager based on a Sagnac interferometer. This thesis research concentrates on the design upgrade and calibration of HEHSI from a proof of concept instrument to a prototype field instrument. Stability is enhanced by removing degrees of freedom and alignment is enhanced by providing for in-situ adjustments. The use of off the shelf components allows for reduced development time and cost constraints. HEHSI is capable of multiple configurations to accommodate sensors and optics with specialized capabilities for multiple wavelength ranges and viewing conditions. With a spectral response of 400 to …

Or-05-6-4: Relating Human Productivity And Annoyance To Indoor Noise Criteria Systems: A Low Frequency Analysis, Erica Eileen Bowden, Lily M. Wang

Durham School of Architectural Engineering and Construction: Faculty Publications

A number of indoor noise criteria systems are used to quantify the background noise in a built environment, including Noise Criteria (NC), Balanced Noise Criteria (NCB), Room Criteria (RC), Room Criteria Mark II (RC Mark II), A-weighted Equivalent Sound Pressure Level (L_Aeq), and others. An on-going debate exists in the acoustical community over which criterion is the most appropriate to use in the variety of ambient noise situations encountered. In an effort to quantitatively support the use of individual criterion, this project subjectively correlates these various criteria with human task performance and perception. Eleven subjects participated in a …

Nebraska Summary 541: Agco Dt200a Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.

Nebraska Summary 542: Dt220a Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.

Test 2258: New Holland Ts125a Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.

Tests 2274 & 2275: Challenger Mt425b Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.

Tests 2305 & 2306: Challenger Mt555b Autopower Iv Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.

Tests 2307 & 2308: Challenger Mt565b Autopower Iv Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.

Test 2335: Challenger Mt565b Techstar Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.

Test 1853: John Deere 4320 Ehydro Diesel Hydrostatic, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA

The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data.

EXPLANATION OF THE TEST PROCEDURES

Purpose

The purpose of …

Test 1866: John Deere 5225 Diesel 9-Speed, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA

The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data.

EXPLANATION OF THE TEST PROCEDURES

Purpose

The purpose of …

Test 1867: John Deere 5325 Diesel 9-Speed, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA

The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data.

EXPLANATION OF THE TEST PROCEDURES

Purpose

The purpose of …