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Articles 1 - 24 of 24
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Effect Of Bulk Flow Modulations On A Normal Jet In Crossflow At A Mean Blowing Ratio Of 0.25, Jeremiah Oertling
Effect Of Bulk Flow Modulations On A Normal Jet In Crossflow At A Mean Blowing Ratio Of 0.25, Jeremiah Oertling
LSU Master's Theses
An experimental wind tunnel has been designed, built, outfitted with automated hot wire anemometry and laser sheet imagery systems methods of instrumentation and tested with the purpose of performing scientific research on the control and stabilization of a jet issuing 90 degrees into a crossflow. After the design and system characterizations were performed, the system was employed as a experimental platform to conduct an investigation of bulk flow modulation of a jet in crossflow. The Mean Blowing ratio investigated was set at 0.25, and the effect of duty cycle, peak to peak blowing ratio and frequency of excitation are investigated. …
Characterization And Tribological Behavior Of Diamond-Like Carbon And Nitrogen-Doped Diamond-Like Carbon Thin Films, Krishna Chaitanya Kadiyala
Characterization And Tribological Behavior Of Diamond-Like Carbon And Nitrogen-Doped Diamond-Like Carbon Thin Films, Krishna Chaitanya Kadiyala
LSU Master's Theses
Diamond-like carbon (DLC) films have been extensively studied for more than two decades due to their highly attractive properties. These films exhibit unique mechanical, electrical and tribological behavior and thus, possess great potential for applications in tribology. However, the high level of internal stress developed and low thermal stability are the main drawbacks. Synthesis of nitrogen-doped DLC (N-DLC) offers the possibility of overcoming these drawbacks. In the present study, DLC and N-DLC films (with low N content) were deposited on Si substrates using a hybrid plasma-assisted CVD/PVD process. Film characterization in terms of microstructure, composition and chemical state of components …
A Thermodynamic Model For Wear In Sliding Contact, Susheel Brahmeshwarkar
A Thermodynamic Model For Wear In Sliding Contact, Susheel Brahmeshwarkar
LSU Master's Theses
Consideration of wear, an irreversible phenomenon, is a very important criterion in design. The knowledge of wear and its behavior enables one to make major considerations to conceptualize and design efficient machinery components with enhanced performance and reliability. The present work deals with the introduction of a novel approach of correlating wear with the thermodynamic properties of the system. The approach involves relating wear to thermodynamic entropy flow in the system using the laws of thermodynamics. This relation is verified experimentally and theoretically by considering a sliding contact in a disk-on-disk configuration for two sets of contacting materials namely Bronze …
Pulsed Vertical Jet In Cross Flow At Mean Blowing Ratios 0.35 And 0.45, Pierre-Emmanuel Jacques Joseph Bouladoux
Pulsed Vertical Jet In Cross Flow At Mean Blowing Ratios 0.35 And 0.45, Pierre-Emmanuel Jacques Joseph Bouladoux
LSU Master's Theses
This thesis deals with a pulsed vertical jet transverse to a cross flow (U∞=1.6m/s) at mean blowing ratios 0.35 and 0.45. First the reasons of this study are explained and the previous work in the field is described. Then the experimental setup, the experimental procedures and the data processing are detailed. The system (wind tunnel and jet) is characterized before studying the Jet in Cross Flow (JICF). The JICF is explored under unforced and forced conditions through LASER sheet visualizations and constant temperature anemometry (CTA) measurements using hot-wire sensors. Blowing ratios ranging from 0.150 to 0.600 are studied …
Modeling Fabrication And Characterization Of A Bio-Micro Thermoelectric Device For Highly Localized Temperature Control, Aparna Prabhakar
Modeling Fabrication And Characterization Of A Bio-Micro Thermoelectric Device For Highly Localized Temperature Control, Aparna Prabhakar
LSU Master's Theses
There is an ever expanding interaction between the fields of micro-electromechanical systems (MEMS) and biology to develop devices to monitor, control and act on living systems. Particularly in the field of cryobiology, there is a need to monitor and control temperature at the cellular level. An important step towards achieving this aim is to fabricate an array of microscale thermoelectric actuators. As a first step for towards achieving such localized control of temperatures in cells and tissues, an array of individually addressable micro-thermoelectric coolers (µTECs) were modeled, characterized, and fabricated. Prefabrication experimentation and modeling were carried out to understand the …
Molecular Dynamics Simulation Study Of Grain Boundary Migration In Nanocrystalline Pd, Shengyu Wang
Molecular Dynamics Simulation Study Of Grain Boundary Migration In Nanocrystalline Pd, Shengyu Wang
LSU Master's Theses
We present a new methodology for measuring the grain boundary mobility for curved boundaries using molecular-dynamics simulation of grain growth in a small, specifically tailored Pd nanocrystalline structure. In the model system, the boundaries move under the forces provided by their curvature and in the presence of the triple junctions. As a consequence of grain boundary migration the boundary area per unit volume is reduced and the mean grain size of grains increases with time. Our investigation shows that at elevated temperatures the activation energy for grain growth in this specifically tailored microstructure is very close to that of grain …
Heat Transfer And Flow Characteristics Inside A Gas Turbine Combustor, Yap-Sheng Goh
Heat Transfer And Flow Characteristics Inside A Gas Turbine Combustor, Yap-Sheng Goh
LSU Master's Theses
Heat transfer and flow characteristics inside a typical can-annulus gas turbine combustor are investigated. This is the first study in a public domain to focus on the convective heat loads to combustor liner due to swirling flow generated by swirler nozzles. The objectives of this study are to physically design an experimental combustor test model, to perform local accurate heat transfer and flow measurements, and to better understand the fundamental thermo-fluid dynamic effects inside a combustor equipped with a swirler nozzle provided by Solar Turbines Inc. The local temperature and heat transfer distribution were determined to locate the heat transfer …
Study Of Particle Growth And Breakdown In Single Size Gamma Prime Distribution And High Temperature Creep In In738lc Nickel Superalloy, Arvind Kumar Dwarapureddy
Study Of Particle Growth And Breakdown In Single Size Gamma Prime Distribution And High Temperature Creep In In738lc Nickel Superalloy, Arvind Kumar Dwarapureddy
LSU Master's Theses
IN738LC, a nickel based superalloy has wide applications in the gas turbine engines because of its ability to retain its strength at high temperatures involved. The stability of the γ' Ni3Al (Ti, Nb) precipitate microstructure which gives the alloy its strength is very important. After an initial annealing at 1200°C for 4 hours and water quenching, a uniform distribution of single size (70nm) γ' fine precipitates is obtained. Growth of the γ' particles, their size and distribution are studied after subsequent annealing heat treatments, conducted at different temperatures for different time periods. The average precipitate size data of …
Performance Modeling Of Explosively Actuated Devices, Adam M. Braud
Performance Modeling Of Explosively Actuated Devices, Adam M. Braud
LSU Master's Theses
Explosively actuated devices (pin pullers, cable cutters, valves, etc) are used extensively to perform critical functions for aerospace, industrial, and defense related applications. The failure of these devices have led to a greater effort to quantify device design and performance. This thesis describes the actuation process of an explosively actuated valve, including: 1) the burning of the solid explosive HMX (C4H8N8O8) and production of its high pressure gas products, 2) the mass transfer of gas products through an actuator to an expansion volume including choked flow effects, 3) the resulting piston motion …
Modeling Of Fiber Reinforced Polymer Confined Concrete Cylinders, Indrani V. Volety
Modeling Of Fiber Reinforced Polymer Confined Concrete Cylinders, Indrani V. Volety
LSU Master's Theses
Fiber Reinforced Polymer (FRP) confined concrete columns have been developed for new construction and rebuilding of concrete piers/piles in engineering structures. Design of these FRP confined concrete columns requires an accurate estimate of the performance enhancement due to the confinement mechanism. Therefore, the key is to develop a confinement model, a model that relates the confined concrete strength with the unconfined concrete strength and the confining pressure provided by the FRP. Due to its closed-form expression and ease of application, design-oriented confinement models predominate in designing FRP confined concrete columns. Design oriented models are directly based on the interpretation of …
Accelerating Micro-Scale Pcr (Polymerase Chain Reactor) For Modular Lab-On-A-Chip System, Pin-Chuan Chen
Accelerating Micro-Scale Pcr (Polymerase Chain Reactor) For Modular Lab-On-A-Chip System, Pin-Chuan Chen
LSU Master's Theses
The polymerase chain reaction (PCR) is a powerful technique used to exponentially amplify specific DNA sequences of interest through repetitive temperature cycling. The temperatures used in PCR are typically 90°C - 94°C for denaturation, 50°C - 70°C for renaturation, and 70°C - 75°C for extension. The double-stranded helix of nucleotides, carrying the genetic information, is separated during denaturation, reacts with chemical primers during renaturation, and becomes a complete, replica, double-stranded DNA helix structure during extension. The primary drawback of current commercial benchtop PCR machine is its cycle time due to its large thermal capacitance, and micro PCR is under developing …
Mesoscale Simulation Of Grain Boundary Diffusion Creep In The Presence Of Grain Growth, Lucian Zigoneanu
Mesoscale Simulation Of Grain Boundary Diffusion Creep In The Presence Of Grain Growth, Lucian Zigoneanu
LSU Master's Theses
Grain-boundary (GB) diffusion creep (Coble creep) is the dominant deformation mechanism for the fine-grained materials under low stress and at elevated temperature. During creep deformation the grains become elongated in the tensile direction because of atoms diffusion along GBs from places in compression to those in tension. Consequently, the GB diffusion rate depends on the normal stress gradient along the boundaries. It is widely accepted that the GB migration generally plays two important roles during Coble creep: one leading to the decrease of the creep rate due to the increase of the grain size by GB migration mediated grain growth …
Modeling And Fabrication Of A Microthermocouple Array, Adam Cygan
Modeling And Fabrication Of A Microthermocouple Array, Adam Cygan
LSU Master's Theses
Cryobiology is the study of how living cells and tissues respond to freezing and exposure to subzero temperatures. Studies in this field are aimed toward improving methods of cryosurgery as well as the storage of cells and tissues. For example, one area of research is to link the biophysical cellular dehydration and intracellular ice formation in cells during tissue freezing to cell viability and mechanical properties after thawing. There is currently a method for measuring dehydration in cells as part of a tissue, but not an adequate method for measuring intracellular ice formation in tissues. A prototype device that would …
A New Method To Determine Radiative Properties Of Rough Solid Surfaces, Raghu Nandan Mutukulla
A New Method To Determine Radiative Properties Of Rough Solid Surfaces, Raghu Nandan Mutukulla
LSU Master's Theses
The radiative properties of the rough surfaces are important both from fundamental and practical standpoint. Thus, there is a need to determine the effect of roughness on radiative properties of materials accurately, as these properties effect the performance of electronic devices, communication devices, optical sensors, and furnaces, amongst others. The effects of roughness are assessed by measuring the reflection coefficients from the carbon rod surfaces and steel 1086 samples over the range of angles 25 to 75 in the visible range and near infrared region. Different levels of roughness are induced on the surfaces by utilizing different grid size sand-paper …
Heat/Mass Transfer In Rotating, Smooth, High Aspect-Ratio (4:1) Coolant Channels With Curved Walls, Eashwar Sethuraman
Heat/Mass Transfer In Rotating, Smooth, High Aspect-Ratio (4:1) Coolant Channels With Curved Walls, Eashwar Sethuraman
LSU Master's Theses
The thesis presents an experimental study of heat/mass transfer coefficient in 4:1 aspect ratio smooth channels with non-uniform cross-sections. Curved leading and trailing edges are studied, for two curvatures of 9.06 m-1 (0.23 in-1) and 15.11 m-1 (0.384 in-1) and for two different curvature configurations. One configuration has curved walls with curvature corresponding to the blade profile (positive curvature on both leading and trailing walls), and the other configuration has leading and trailing walls that curve inwards into the coolant passage (negative curvature on the leading surface and positive curvature on the trailing surface). The experiments are conducted in a …
Simulations Of A Modified Micro-Scale Electrophoretron, Nada Elmajdoub
Simulations Of A Modified Micro-Scale Electrophoretron, Nada Elmajdoub
LSU Master's Theses
This paper presents theoretical analysis and numerical simulations of a modified micro-scale electrophoretron adapted for cycling reaction applications (PCR, LDR...). The electrophoretron consists of a closed-loop microchannel. If one part of the length of the channel has an electroosmotic mobility of an opposite sign than the remaining part, a continuous cyclic motion of the fluid can be sustained if a potential difference is applied on two electrodes strategically placed along the channel. Conservation of mass leads to the formation of a pressure gradient and a related hydrodynamic flow. Under appropriate combination of design parameters, the combined Electroosmotic -hydrodynamic flow contributes …
Mesoscale Predictions For The Dynamic Compaction Of Explosively-Coated Aluminum Micro-Particles, Michael Wayne Crochet
Mesoscale Predictions For The Dynamic Compaction Of Explosively-Coated Aluminum Micro-Particles, Michael Wayne Crochet
LSU Master's Theses
Conventional granular explosives are widely used in aerospace and defense-related industries. Powdered metals are often mixed with high explosives to enhance detonation. The effectiveness of these mixtures is limited by the slow burning of the metal relative to the explosive and their sensitivity to mechanical loading. Granular energetic composites, composed of an aluminum core coated with a layer of the high explosive RDX (C3H6N6O6), may be a high-performance alternative to conventional explosives because of a higher metal combustion rate and lower impact sensitivity. Though the technology required to manufacture granular energetic composites …
A Generalized Approach For The Control Of Micro-Electromechanical Relays, Mohamed Abdelrahman Younis
A Generalized Approach For The Control Of Micro-Electromechanical Relays, Mohamed Abdelrahman Younis
LSU Master's Theses
MEMS (Micro-Electromechanical Systems) is an area of research and applications that is becoming increasingly popular. It's mainly concerned with integrating micro-mechanical transducers with micro-electronic circuits on common substrates, traditionally silicon, through micro-fabrication. Instead of traditionally having the transducer and the communicating (or control) circuit as two separate entities, MEMS miniaturizes and combines them on a single chip, giving it several advantages, saving space, money, and increasing the sensitivity and accuracy of the integrated system. A micro-electromechanical relay is a type of MEM devices that is becoming increasingly important in a wide range of industries such as the computer industry, the …
Thermal Management Of Micro Gas Chromatographs, Chetan Ramesh
Thermal Management Of Micro Gas Chromatographs, Chetan Ramesh
LSU Master's Theses
Gas chromatography is an analytical technique for separating and analyzing individual components in a gas mixture. Applications of gas chromatographs (GCs) include chemical analysis, environmental maintenance, green house gases monitoring, and forensic analysis when used in conjunction with mass spectrometry. There has been a tremendous interest in miniaturization of gas chromatograph systems because of significantly reduced size, portability, fast response times, low power consumption and low cost. Isothermal analysis is a chromatographic analysis at one column temperature. In temperature programming, a linear increase of column temperature with time is used during the course of the analysis. Temperature programming facilitates separation …
Design And Test Of A Displacement Workspace Mapping Station For Articular Joints, Michael Daly Guillet
Design And Test Of A Displacement Workspace Mapping Station For Articular Joints, Michael Daly Guillet
LSU Master's Theses
In 2003, 267,000 Americans received total knee replacements prohibiting high impact athletics for the remainder of a patient’s life. A better understanding of the movement and constraint of the knee is necessary to provide more realistic motion of or possibly eliminate the need for joint prosthetics. Fixed Orientation Displacement Workspaces (FODW) can be applied to study the relationship of the passive constraint system and six (6) degree of freedom (DOF) movement of the human knee. A FODW consists of the volume of possible positions the tibia/fibula can occupy relative to a fixed femur without changing the relative orientation of the …
Two-Phase Flow In High Aspect Ratio, Polymer Microchannels For Reagent Delivery Applications, Estelle Evans
Two-Phase Flow In High Aspect Ratio, Polymer Microchannels For Reagent Delivery Applications, Estelle Evans
LSU Master's Theses
Multiphase flow in microfluidics is an increasingly growing field, especially in biotechnology. For instance, a steady-state slug flow would benefit lab-on-a-chip drug delivery methods. This flow would not only use minute amounts of reagents, but it would also decrease the sample processing time. Thus, researching a steady-state plug flow in a microchannel is beneficial to the drug delivery field. Five PMMA, directly-milled microchannels [2: Aspect Ratio 1 (with and without pressure ports, 2): Aspect ratio 2 (with and without pressure ports), and 1: Aspect Ratio 3 (without pressure ports)] were manufactured. These channels were then cleaned, and a PMMA cover …
Jet Impingement Cooling Configurations For Gas Turbine Combustion, Eric Ian Esposito
Jet Impingement Cooling Configurations For Gas Turbine Combustion, Eric Ian Esposito
LSU Master's Theses
Impinging jets are commonly used to enhance heat transfer in modern gas turbine engines. Impinging jets used in turbine blade cooling typically operate at lower Reynolds numbers in the range of 10,000 to 20,000. In combustor liner cooling, the Reynolds numbers of the jets can be as high as 60,000. The present study is aimed at experimentally testing two different styles of jet impingement geometries to be used in backside combustor cooling. The higher jet Reynolds numbers lead to increased overall heat transfer characteristics, but also an increase in crossflow caused from spent air. The crossflow air has the effect …
Numerical Solution Of Flow Resistance In Outflow Pathway And Intravitreal Drug Delivery In Vitrectomised Eyes, Jyoti Gururaj Kathawate
Numerical Solution Of Flow Resistance In Outflow Pathway And Intravitreal Drug Delivery In Vitrectomised Eyes, Jyoti Gururaj Kathawate
LSU Master's Theses
In this study, numerical computations of the ocular fluid dynamics in a human eye are presented with a perspective of understanding the mechanisms of increased flow resistance. In the present study, the TM is represented as a multilayered-graded porous structure with specific pore size and void fraction. The flow patterns and pressure distribution in anterior chamber are analyzed to delineate key flow mechanism; the shear stresses on the lens, iris and IW of SC are also examined to locate the maximum values. Inside the human eye, the largest pressure drop occurs across JCT and IW of SC. The highest pressure …
Experimental Analysis Of Mechanical Seal Design With Enhanced Thermal Performance, Ainsworth Gidden
Experimental Analysis Of Mechanical Seal Design With Enhanced Thermal Performance, Ainsworth Gidden
LSU Master's Theses
For industries that use pumps and mixers in their process operations, it is of paramount importance to control the leakage from these equipments. The leakage presents safety hazards and economic loss. It is widely believed that the majority of downtime associated with a pump or a mixer is the result of a mechanical seal failure. Therefore, it is important for these industries to have a mechanical seal that is a reliable performer and enables a longer operational life than what exist in the market at present. The aim of this research was to design and test a mating ring with …