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Articles 1 - 13 of 13
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Design, Fabrication And Characterization Of A New Wind Tunnel Facility – Linear Cascade With A Wake Simulator, Jean-Philippe Junca-Laplace
Design, Fabrication And Characterization Of A New Wind Tunnel Facility – Linear Cascade With A Wake Simulator, Jean-Philippe Junca-Laplace
LSU Master's Theses
A new wind tunnel has been designed and constructed at the LSU Mechanical Engineering Laboratories. The objective was to design a versatile test facility, suitable for a wide range of experimental measurements on turbine blades. The future study will investigate the impact of unsteady inflow conditions on film cooling performance. More specifically, it will study how the unsteady flow due to the upstream passing wakes coming from the front row vane affects the film cooling performances on the turbine blades. The test section consists of a four passage linear cascade composed of three full blades and two shaped wall blades. …
Gas Turbine Blade Tip And Near Tip Heat Transfer With Film Cooling, Gregory Kramer
Gas Turbine Blade Tip And Near Tip Heat Transfer With Film Cooling, Gregory Kramer
LSU Master's Theses
Gas turbine blade tips experience very high thermal loads due to high temperature combustion gases and tip leakage flows. This leads to the tip region being very susceptible to experiencing failures. To better understand these effects, experiments were performed in a suction-type low speed wind tunnel cascade to determine heat transfer coefficients and film cooling effectiveness distributions on a highly-loaded 2-D gas turbine blade model in the tip and near-tip regions. The blade shape was generated to match the pressure coefficients of the operating turbine blade design. The model featured multiple tip and pressure side film cooling holes and a …
Small Footprint High Flow Rate Microdevice For Rare Target Cell Capture, Taehyun Park
Small Footprint High Flow Rate Microdevice For Rare Target Cell Capture, Taehyun Park
LSU Doctoral Dissertations
A novel high flow rate cell capture design was introduced to overcome the limitations of the current technologies or methods for rare target cell capture. Even though the rare target cell capture using BioMEMS technology has great potential for cancer diagnosis, previous rare cell capture research could not overcome the limitations of low flow rate or low recovery rate. Rare cell research requires precise sample preparation for accurate results. A new method of preparation for a single or a precise number of target cell was introduced. Current sample preparation methods which are not suitable for rare cell research, such as …
Embedded Piezoelectric Fiber Composite Sensors For Applications In Composite Structures, Hari Prasad Konka
Embedded Piezoelectric Fiber Composite Sensors For Applications In Composite Structures, Hari Prasad Konka
LSU Doctoral Dissertations
Health monitoring of the composite structures is an important issue that must be addressed. Embedded sensors could be an effective way to monitor the health of composite structures continuously and which could also avoid the catastrophic failures of composite structures. Piezoelectric-fiber-composite sensors (PFCS) made from micro-sized Lead Zirconate Titanate (PZT) fibers have great advantages over the traditional bulk PZT sensors for embedded sensor applications. PFCS as an embedded sensor will be an ideal choice to continuously monitor the stress/strain levels and health conditions of composites. This work presents a critical study on using PFCS as an effective embedded sensor within …
Molecular Dynamics Simulation Studies Of Surface-Stress Effects In Metallic Nanostructures, Jijun Lao
Molecular Dynamics Simulation Studies Of Surface-Stress Effects In Metallic Nanostructures, Jijun Lao
LSU Doctoral Dissertations
Using molecular dynamics (MD) simulations we investigate the surface-stress-induced structural transformations and pseudoelastic behavior in palladium (Pd) crystalline nanowires. For a <100> initial crystal orientation our studies indicate that the surface stress can cause Pd nanowires to spontaneously undergo structural changes with characteristics that are determined by the wire cross-sectional area. Specifically, when the cross-sectional area is below 2.18nm x 2.18nm the wire changes spontaneously its crystal structure from the initial fcc structure to a body-centered-tetragonal (bct) structure. In wires of larger cross-sectional area (i.e., 2.57nm x 2.57nm) the structural transformation is achieved via a spontaneous lattice reorientation leading to an …
V2o5-Wo3 Composite Films And Surface-Coated Licoo2 For Enhanced Li-Ion Intercalation Properties, Chuan Cai
V2o5-Wo3 Composite Films And Surface-Coated Licoo2 For Enhanced Li-Ion Intercalation Properties, Chuan Cai
LSU Master's Theses
We have investigated the enhanced Li-ion intercalation properties of two different materials, which are V2O5-WO3 composite and surface-coated LiCoO2. A simple and novel solution processing method is employed to prepare V2O5-WO3 composite films that demonstrate enhanced Li-ion intercalation properties for applications in Li-ion batteries or electrochromic displays. This solution processing method employs precursors that only contain the elements of V, W, O and H, which avoids impurity elements such as Na that has been commonly used in other solution methods (e.g. using precursors of sodium metavanadate and sodium tungstate solution). The V2O5-WO3 composite films show enhanced Li-ion intercalation properties compared …
On The Thermodynamics Of Degradation, Mehdi Amir Darehbidi
On The Thermodynamics Of Degradation, Mehdi Amir Darehbidi
LSU Doctoral Dissertations
All materials when subjected to fatigue loading are prone to failure if the number of cycles exceeds a certain level. Prediction of the number of cycles to failure is, therefore, of utmost importance in nearly all engineering applications. The existing methods for evaluating the fatigue life are tedious, expensive, and extremely time consuming as fatigue often takes many thousands to millions of cycles until failure occurs. Therefore, methods that can readily estimate the number of cycles to failure are highly desirable. In this work, innovative solutions to fatigue problems are presented and their practical significance is discussed. The premise of …
Thermodynamic Approach To Fatigue Failure Analysis In Metals And Composite Materials, Mehdi Naderi Abadi
Thermodynamic Approach To Fatigue Failure Analysis In Metals And Composite Materials, Mehdi Naderi Abadi
LSU Doctoral Dissertations
Fatigue is a dissipative process and must obey the laws of thermodynamics. In general, it can be hypothesized that the degradation of machinery components is a consequence of irreversible thermodynamic processes that disorder a component, and that degradation is a time dependent phenomenon with increasing disorder. This suggests that entropy —a fundamental parameter in thermodynamics that characterizes disorder— offers a natural measure of component degradation. The majority of the existing methods for prediction of fatigue are limited to the study of a single fatigue mode, i.e., bending or torsion or tension-compression. Further, the variability in the duty cycle in a …
Two-Stage Biaxial Thermomechanical Cycle Of Shape Memory Polymer Based Syntactic Foam, Abraham Michael King
Two-Stage Biaxial Thermomechanical Cycle Of Shape Memory Polymer Based Syntactic Foam, Abraham Michael King
LSU Master's Theses
A shape memory polymer (SMP) is a polymeric material that exhibits shape memory behavior. It can be “programmed” to take on a desired shape and “recovered” to revert back to its original shape. This ability to remember multiple shapes and switch between them with the application of a stimulus from an outside source is very desirable in certain applications. By dispersing glass microspheres in a SMP matrix, a syntactic foam is created that retains much of the shape memory capabilities but has higher strength and lower density than the pure SMP. These characteristics make this material a good candidate for …
Pool Boiling Enhancement Via Micro Ratchets, Lance Austin Brumfield
Pool Boiling Enhancement Via Micro Ratchets, Lance Austin Brumfield
LSU Master's Theses
Nucleate boiling is an attractive method for achieving high heat flux at low superheat temperatures. It is frequently used for industrial applications such as heat exchangers and is being considered to cool advanced central processing units (CPU) which produce heat fluxes on the order of 1 MW/m2 and are becoming increasing less efficient to cool via forced conduction of air. The issues with implementing nucleate boiling as a cooling mechanism lies in the difficulty of quantifying the complex and numerous mechanisms which control the process. A comprehensive nucleate boiling model has yet to be formulated and will required in order …
A Biomimic Self-Healing Shape Memory Polymer Based Syntactic Foam For Smart Structural Composites, Jones Nji
A Biomimic Self-Healing Shape Memory Polymer Based Syntactic Foam For Smart Structural Composites, Jones Nji
LSU Doctoral Dissertations
This study explored the development of a new self-healing Polystyrene Shape Memory Polymer (PSMP) based syntactic foam for service life extension in structural polymeric composites. The objective was to self-heal structural-length scale damage in an autonomous, efficient, timely and repeatable manner at the molecular-length scale. Self-healing is achieved through a novel two step close-then-heal (CTH) self-healing scheme, designed to mimic the natural biological process of wound healing in humans. A new methodology to fabricate three-dimensional (3-D) fiber reinforced shape memory polymer syntactic foam for structural applications was developed. The effect of impact energy on the ability for the 3-D fiber …
Effect Of Piezoelectric Actuation On Curved Beams And Single Lap Joints, Calicia Johnson
Effect Of Piezoelectric Actuation On Curved Beams And Single Lap Joints, Calicia Johnson
LSU Master's Theses
Piezoelectric materials have seen a significant usage increase over the past decade. They have been found to be effective as either sensors or actuators in smart structure applications, which allows them to act more as an adaptive system rather than a passive system. Piezoelectric materials are very effective transducers which convert mechanical energy into electrical energy, known as the direct piezoelectric effect or they have the ability to convert electrical energy to mechanical energy, known as the converse piezoelectric effect. The absence of additional mechanical parts, its lightweight and high strength to weight ratio is what make piezoelectric materials so …
The Design And Modification Of A Sputter System For Dc Reactive Sputtering Of Alumina And Zirconia Thin Films, Diane Van Ho
The Design And Modification Of A Sputter System For Dc Reactive Sputtering Of Alumina And Zirconia Thin Films, Diane Van Ho
LSU Master's Theses
Yttria-stabilized zirconia (7% YSZ) is the most used material for thermal barrier coatings (TBCs) to reduce the conductive heat transfer on turbine blades, but it is not resistant to infrared radiation. In order to reduce radiation heat transfer, alternating materials, such as alumina and zirconia, can be used to fabricate multi-layer coatings in which each layer is optimized to reflect a targeted range of wavelength. This research aims to fabricate these multi-layer coatings by reactive magnetron sputtering. Reactive magnetron sputtering is the sputtering of an elemental target in the presence of a reactive gas that will react with the target …