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LSU Master's Theses

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Full-Text Articles in Engineering

Experimental And Computational Modeling Of Granular Materials, Orlando Boscan Jan 2004

Experimental And Computational Modeling Of Granular Materials, Orlando Boscan

LSU Master's Theses

4-inch cubical sand specimens were been tested under drained conditions using a wide range of stress paths. The testing was performed by means of a true (cubical) triaxial device that has been conditioned for this study. This testing set-up consisted of a servo-controlled, single-boundary type apparatus, with six flexible membranes that create a center cavity surrounding the soil specimens. This thesis illustrates the functioning of the triaxial device, including detailed descriptions of the device components, sample preparation, and a practical application related to the mechanical characterization of granular materials using critical state soil mechanics. An experimental program, based on the …

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Performance Assessment Of Coated Cemented Carbide Tools In Turning Aisi 1018 Steel, Mohamad Nouilati Jan 2004

Performance Assessment Of Coated Cemented Carbide Tools In Turning Aisi 1018 Steel, Mohamad Nouilati

LSU Master's Theses

In this study, the machining performance of a series of commercially available coated tungsten based cemented carbides, with 55o diamond shape, were investigated during finish turning of AISI 1018 steel under dry conditions. The inserts tested had a coating of TiN, Al2O3, TiN/Al2O3 and TiC/Al2O3/TiN respectively. For comparison, uncoated cemented tungsten carbide was also tested under the same cutting conditions. The coated tools exhibited superior wear resistance over the uncoated tool. The TiC/Al2O3/TiN coated tool had the lowest flank wear due to the high abrasive resistance of the TiC layer. The Al2O3 coated tool showed superior wear-resistance over the TiN/Al2O3 …

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An Experimental Investigation Of Whirl Instability Including Effects Of Lubricant Temperature In Plain Circular Journal Bearings, Darryl, Jr. Chauvin Jan 2003

An Experimental Investigation Of Whirl Instability Including Effects Of Lubricant Temperature In Plain Circular Journal Bearings, Darryl, Jr. Chauvin

LSU Master's Theses

The purpose of this thesis is to experimentally investigate the effect of lubricant temperature on the presence of whirl instability in journal bearings. The first set of conditions that are studied is an extremely low eccentricity rotor and the occurrence of oil whirl at the start-up of the experiment. Lubricant temperature, bearing temperature, frequency and amplitude of vibration, and rotational speed are monitored and analyzed in relation to presence of whirl instability. Additionally, another rotor with a slightly higher eccentricity is tested with respect to the presence of such instability. Particularly with this rotor, the system is brought just below …

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Forced Bubble Columns, Jia Ma Jan 2003

Forced Bubble Columns, Jia Ma

LSU Master's Theses

In many chemical, biochemical and pharmaceutical industrial processes, bubble breakage is very important for gas component to dissolve and react with surrounding liquid. The overall mass transfer performance can be improved greatly when the interfacial gas-liquid area is increased due to bubble breakup. In forced bubble columns operating at low forcing frequency (<30Hz) and small forcing amplitude (<3mm), bubbles undergo phenomenal breakage. Mass transfer coefficient, kLa, is increased to 250%~625% of the no forcing value depending on flow regime and configuration of membrane and piston. Two different mechanisms, induced shear slug breakage in the gas feeder tube for bubbly flow and resonant frequency bubble breakage in the column fluid phase for jet flow, seem to at work.

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Structure And Mechanical Properties Of Ti-Si-N Coatings, Xiaodong Zhang Jan 2003

Structure And Mechanical Properties Of Ti-Si-N Coatings, Xiaodong Zhang

LSU Master's Theses

In order to better define conditions under which ~{!0~}super-strengthening~{!1~} occurs in the Ti-Si-N system, we performed detailed experimental studies on how the structure and mechanical properties of Ti-Si-N coatings are influenced by the deposition temperature. Different series of Ti-Si-N specimens were prepared in an inductively coupled plasma (ICP)-assisted reactive sputtering system at both low and high temperatures. Coating compositions were measured by Rutherford backscattering spectrometry (RBS) technique, surface roughness was examined on an atomic force microscope (AFM), coating thicknesses were obtained by performing cross-sectional scanning electron microscopy (SEM), and their structure examined with transmission electron microscopy (TEM). Vibrational frequency results …

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A Disjoining Pressure For Small Contact Angles And Its Applications, Qingfang Wu Jan 2003

A Disjoining Pressure For Small Contact Angles And Its Applications, Qingfang Wu

LSU Master's Theses

A thin liquid film experiences additional intermolecular forces when the film thickness h is less than roughly 100 nm. The effect of these intermolecular forces at the continuum level is captured by the disjoining pressure . Since dominates at small film thicknesses, it determines the stability and wettability of thin films. To leading order, a thin film can be treated as uniform and . This form, however, cannot be applied to films with non-zero contact angles. A recent ad-hoc derivation to include the slope leads to a that allows a contact line to move without slip. This work derives a …

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Heat Transfer In Outdoor Aquaculture Ponds, Jonathan Lamoureux Jan 2003

Heat Transfer In Outdoor Aquaculture Ponds, Jonathan Lamoureux

LSU Master's Theses

An energy balance was developed for heated and unheated earthen aquaculture ponds to 1) determine the relative importance of energy transfer mechanism affecting pond temperature; 2) predict pond temperatures; 3) estimate the energy required to control pond temperatures, and 4) recommend efficient heating and cooling methods. PHATR (Pond Heating and Temperature Regulation), a computer program using 4th order Runge-Kutta numerical method was developed to solve the energy balance using weather, flow rate and pond temperature data. By comparing measured and modeled pond temperatures, the average difference (the average bias) was 0.5°C for unheated ponds and 2.4°C for heated ponds. The …

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Thermohydrodynamic Analysis Of Compressible Gas Flow In Compliant Foil Bearings, Zhengchun Peng Jan 2003

Thermohydrodynamic Analysis Of Compressible Gas Flow In Compliant Foil Bearings, Zhengchun Peng

LSU Master's Theses

This thesis deals with the development of mathematical models and numerical schemes for simulating the hydrodynamic pressure and temperature rise of compliant foil bearings lubricated by a thin gas film in between its compliant bearing surface and the rotating shaft. The model accounts for the compressibility of gas, the compliance of the bearing surface, and the interaction between the pressure field and temperature field of the gas film in the bearing system. Numerical solutions obtained over a fairly large range of operating speeds show excellent agreement with existing experimental data from both load performance test and bearing temperature measurement. A …

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Immiscible And Miscible Gas-Oil Displacements In Porous Media, Madhav Mukund Kulkarni Jan 2003

Immiscible And Miscible Gas-Oil Displacements In Porous Media, Madhav Mukund Kulkarni

LSU Master's Theses

Gas Injection is the second largest EOR process in U.S. To increase the extent of the reservoir contacted by displacing fluids, gas and water are injected intermittently - water-alternating-gas (WAG) process, is widely practiced. This experimental study is aimed at evaluating the WAG process performance in short and long cores as a function of gas-oil miscibility and brine composition. This performance evaluation has been carried out by comparing oil recoveries between WAG injection and continuous gas injection (CGI). Miscible (2500 psi) and immiscible (500 psi) floods were conducted using Berea cores, n-Decane and two different brines, namely the commonly used …

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Precipitate Growth Features In The Duplex Size Gamma Prime Distribution In The Superalloy In738lc, Indranil Roy Jan 2003

Precipitate Growth Features In The Duplex Size Gamma Prime Distribution In The Superalloy In738lc, Indranil Roy

LSU Master's Theses

IN738LC is a modern, nickel base superalloy utilized at high temperatures in aggressive environments. Durability of this superalloy is dependent on the retention of strengthening by Gamma Prime precipitates. The precipitate growth features in the duplex size (fine and coarse) precipitate distribution was studied by heating the alloy for various times in vacuum at selected temperatures in the range 800 °C to 1100 °C. Increasing the holding times from 1 hour to 100 hours shows joining of the fine particles to form bigger particles, leading to distinct raft patterns. Two different Gamma Prime precipitate growth processes had been observed: merging …

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Freeway Accident Analysis Using Second Order Statistics, Khasim Khasimul Shaik Jan 2003

Freeway Accident Analysis Using Second Order Statistics, Khasim Khasimul Shaik

LSU Master's Theses

This research focuses on the use of historical freeway traffic data for comparison of the precursory traffic conditions to that accident occurrence by using 15-minute traffic speed contour maps. The second order statistics measures, namely angular second moment (ASM), contrast and entropy were used as the traffic performance measures in order to compare the two situations. The data used is from I-4 freeway traffic condition database, stored in a SQL server and 1999 year accident database for the same I-4 freeway. The study section is located in Orlando, Florida. The approach shows an approach to understand the performance of the …

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Field Evaluation Of In-Situ Test Technology For Qc/Qa During Construction Of Pavement Layers And Embankments, Munir Darwish Nazzal Jan 2003

Field Evaluation Of In-Situ Test Technology For Qc/Qa During Construction Of Pavement Layers And Embankments, Munir Darwish Nazzal

LSU Master's Theses

With the coming changes from an empirical to mechanistic-empirical pavement design, it becomes essential to move towards changing the quality control/quality assurance (QC/QA) procedures of compacted materials from a unit weight-based criterion to a stiffness/strength based criterion. The non-destructive in-situ tests such as Geogauge, Dynamic Cone Penetrometer (DCP), and Light Falling Weight Deflectometer (LFWD) can be used as effective tools in the assessment of subsurface conditions and in evaluating the stiffness of pavement materials and embankment. This thesis evaluates the potential use of these three devices to reliably measure the stiffness characteristics of highway materials for possible application in the …

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The Determination Of Appropriate Phosphogypsum: Class C Fly Ash : Portland Type Ii Cement Compositions For Use In Marine Applications, Pradyot Sudhakar Deshpande Jan 2003

The Determination Of Appropriate Phosphogypsum: Class C Fly Ash : Portland Type Ii Cement Compositions For Use In Marine Applications, Pradyot Sudhakar Deshpande

LSU Master's Theses

Phosphogypsum (PG, CaSO4·2H2O) is a waste by-product produced during the wet manufacturing phosphoric acid process. Phosphoric acid is manufactured by processing phosphate rock that contains relatively high concentrations of naturally occurring radioactive impurities which makes PG a radioactive material. PG also contains certain trace metals including As, Ba, Cd, Cr and Pb and radioactive contaminants such as Radium226 and Uranium238 that pose potential hazard to human health and the environment. According to USEPA, the current allowable disposal method for PG is stack piling. This research was focused on stabilizing PG with Portland Type II …

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Mathematical Modeling Analysis Of Floating Bead Biofilter Applications To Domestic Wastewater Treatment, Qiang Wu Jan 2003

Mathematical Modeling Analysis Of Floating Bead Biofilter Applications To Domestic Wastewater Treatment, Qiang Wu

LSU Master's Theses

Floating Bead Biofilters (FBFs) have been applied to aquacultural recirculating tanks and domestic wastewater treatment systems for controlling total ammonia nitrogen (TAN), biochemical oxygen demand (BOD), and total suspended solids (TSS). Support modified media in these FBFs provide a large surface area (1150~1475 m2/m3) so that the active biofilm can be retained in the FBF by attaching to the media surface. Understanding the theories involved in biofilm processes greatly helps in sizing, designing, and modeling of FBF systems. Fundamental biofilm processes like mass transport of various substrates into the biofilm and the substrate utilization within the biofilm were studied. A …

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Evaluation Of Static Low Density Media Filters For Use In Domestic Wastewater Treatment, Cynthia Wagener Jan 2003

Evaluation Of Static Low Density Media Filters For Use In Domestic Wastewater Treatment, Cynthia Wagener

LSU Master's Theses

Static Low Density Media (SLDM) filters are submerged granular medium filters that contain a static matrix of floating media. These filters provide concurrent biological and physical treatment, and are therefore classified as bioclarifiers. Through different design and operation strategies, SLDM filters may be used for a variety of functions such as: solid-liquid separation alone, organic conversion and solids capture, nitrification and solids capture, and denitrification and solids capture. For operation as an aerobic unit, an external aeration strategy was developed to preserve the static nature of the bed. In this study, SLDM filters treated a highly variable flow domestic wastewater …

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A Hybrid Model-Based And Memory-Based Short-Term Traffic Prediction System, Ciprian Danut Alecsandru Jan 2003

A Hybrid Model-Based And Memory-Based Short-Term Traffic Prediction System, Ciprian Danut Alecsandru

LSU Master's Theses

Short-term traffic forecasting capabilities on freeways and major arterials have received special attention in the past decade due primarily to their vital role in supporting various travelers' trip decisions and traffic management functions. This research presents a hybrid model-based and memory-based methodology to improve freeway traffic prediction performance. The proposed methodology integrates both approaches to strengthen predictions under both recurrent and non-recurrent conditions. The model-based approach relies on a combination of static and dynamic neural network architectures to achieve optimal prediction performance under various input and traffic condition settings. Concurrently, the memory-based component is derived from the data archival system …

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Circuitry For A Remotely Powered Bio-Implantable Gastric Electrical Stimulation System, Satish Kona Jan 2003

Circuitry For A Remotely Powered Bio-Implantable Gastric Electrical Stimulation System, Satish Kona

LSU Master's Theses

Power to bio-implantable devices is usually supplied through a battery implanted with the system or through wires extending to an outside power source. The latter case with wires protruding out of the body can be unaesthetic in appearance and can cause infection. In this research, we consider an alternative way to power a bio-implantable microsystem. It involves using rechargeable lithium batteries. Here, power is delivered remotely to charge implanted battery or batteries. This approach avoids periodic surgery necessary for battery replacement. It also does not tie a person to an external power source at all times. This improves patient’s quality …

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Adaptive Image Filtering Using Run-Time Reconfiguration, Nitin Srivastava Jan 2003

Adaptive Image Filtering Using Run-Time Reconfiguration, Nitin Srivastava

LSU Master's Theses

This thesis implements an adaptive linear smoothing image filtering algorithm, on a Virtex™-E FPGA using run-time reconfiguration (RTR). An adaptive filter uses a filtering window that runs over the entire image pixel-by-pixel, generating new (filtered) values of the pixels. As the name suggests, an adaptive filter can adapt to the varying nature of an image by adjusting the coefficients of the filtering window depending upon the local variance in the intensity values of pixels. It filters an image in a non-uniform fashion providing greater smoothing in largely uniform areas of the image and lesser smoothing when it encounters edges and …

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Orthogonal Frequency Division Multiplexing Modulation And Inter-Carrier Interference Cancellation, Yao Xiao Jan 2003

Orthogonal Frequency Division Multiplexing Modulation And Inter-Carrier Interference Cancellation, Yao Xiao

LSU Master's Theses

The Orthogonal Frequency Division Multiplexing (OFDM) technique, wireless channel models, and a pair of new intercarrier interference self-cancellation methods are investigated in this thesis. The first chapter addresses the history of OFDM, along with its principles and applications. Chapter two consists of three parts: the principal, the modern OFDM models, and the Peak to Average Power Ratio (PAPR) problem. Chapter two also summarizes possible PAPR solutions. Chapter three discusses a series of well-known wireless channel models, as well as the general formula for wireless channels. In Chapter four, ICI problem has been discussed, along with its existing solutions. Chapter five …

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Staying Afloat: A Risk Analysis Study Of Flooding In South Louisiana, Marlene Tomaszkiewicz Jan 2003

Staying Afloat: A Risk Analysis Study Of Flooding In South Louisiana, Marlene Tomaszkiewicz

LSU Master's Theses

For decades, South Louisiana has been battling with flood risk. The area has been inundated with flood waters several times, whether it is due to tropical weather, strong rainfall events, or rising waters. This has resulted in millions of dollars in damages, and in some instances, the same home has been affected multiple times. Many agree that South Louisiana is just not a livable area to begin with; the risk is just too great. However, abandoning the area is simply not an option. As a result, the flood risk battle ensues. How much risk are we talking about? The Federal …

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Development Of A Performance-Based Design Approach And Related Loads For Facilities Designated As Essential During A Hurricane Event, Joffrey Elliott Easley Jan 2003

Development Of A Performance-Based Design Approach And Related Loads For Facilities Designated As Essential During A Hurricane Event, Joffrey Elliott Easley

LSU Master's Theses

Historically, shelters and other facilities designated as "essential" during hurricanes have experienced unacceptable damage during recent hurricanes, exposing the occupants to uncomfortable and dangerous conditions. One of the reasons for this is the lack of standards or design guidelines addressing the special considerations required for such facilities. A new approach to the design of essential facilities in hurricane regions is proposed. The goal of this work is to create a tool for improving the safety and serviceability of evacuation shelters and other critical facilities utilized during hurricane events. This is achieved by developing a new philosophy based on selection of …

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Carbon Dioxide Capture From Flue Gas Using Regenerable Sodium-Based Sorbents, Ya Liang Jan 2003

Carbon Dioxide Capture From Flue Gas Using Regenerable Sodium-Based Sorbents, Ya Liang

LSU Master's Theses

The overall objective of this project is to develop a simple and inexpensive process to separate carbon dioxide (CO2) as an essentially pure stream from a fossil fuel combustion gases using a regenerable sodium-based sorbent. This objective of this phase of the project is to evaluate CO2 capture using sodium-based sorbents in single-cycle and multicycle tests as a function of calcination and carbonation conditions. The sorbent precursors investigated were sodium bicarbonates supplied by Church and Dwight, Inc., and natural trona supplied by Solvay. All precursors were first calcined to sodium carbonate and then converted to sodium bicarbonate (NaHCO3) or Wegscheider’s …

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Instantaneously Trained Neural Networks With Complex Inputs, Pritam Rajagopal Jan 2003

Instantaneously Trained Neural Networks With Complex Inputs, Pritam Rajagopal

LSU Master's Theses

Neural network architectures that can handle complex inputs, such as backpropagation networks, perceptrons or generalized Hopfield networks, require a large amount of time and resources for the training process. This thesis adapts the time-efficient corner classification approach to train feedforward neural networks to handle complex inputs using prescriptive learning, where the network weights are assigned simply upon examining the inputs. At first a straightforward generalization of the CC4 corner classification algorithm is presented to highlight issues in training complex neural networks. This algorithm performs poorly in a pattern classification experiment and for it to perform well some inputs have to …

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Analysis Of Laboratory And Field Pull-Out Tests Of Geosynthetics In Clayey Soils, Ather Mohiuddin Jan 2003

Analysis Of Laboratory And Field Pull-Out Tests Of Geosynthetics In Clayey Soils, Ather Mohiuddin

LSU Master's Theses

Soil reinforcement interaction is a key issue in the design of reinforced soil structures. Therefore, it is important to analyze the pull-out mechanism, and to evaluate the interaction between the soil and geosynthetic reinforcement. Majority of pull-out tests performed to date were in granular soils, and very few tests were reported in cohesive soils. The shortage of in-situ granular materials and the availability of cohesive soils in Louisiana have initiated a growing interest in using the marginal soils as backfill material. To investigate the soil-geosynthetic interaction parameters, series of laboratory and field pull-out tests were conducted using various geosynthetics (geogrids: …

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Axis-Switching In Square Coaxial Jets, Victor Piffaut Jan 2003

Axis-Switching In Square Coaxial Jets, Victor Piffaut

LSU Master's Theses

Airflow from single and coaxial contoured nozzles with a square cross section is studied using constant temperature anemometry. The inner to outer jet velocity ratio is 1.5. The Reynolds number of the outer jet based on the hydraulic diameter of the outer nozzle exit is 15,300. Results are compared to previous data obtained with circular nozzles under the same conditions. Properties of the jets and their shear layers such as turbulence shear layer thicknesses and growth rates were derived from the velocity record. The mixing between the jets and with the external flow was found to be enhanced by passive …

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Effect Of Jet Hole Arrays Arrangement On Impingement Heat Transfer, Lujia Gao Jan 2003

Effect Of Jet Hole Arrays Arrangement On Impingement Heat Transfer, Lujia Gao

LSU Master's Theses

A comprehensive investigation on impingement heat transfer of different jet array arrangements is presented. Experiments on the inline jet arrays and the linearly stretched arrays are performed using transient liquid crystal technique. Three experimented basic inline jet arrays are configurations 4X4, 8X4 and 8X8. Two experimented cases for the linearly stretched arrays are the uniform diameter case and the varying diameter case. For the inline jet arrays, three jet heights Z/D=1, 3 and 5 and three Reynolds numbers Re=5000, 10000 and 15000 are investigated. For linearly stretched arrays, the same three jet heights and Re=2000, 6000 and 10000 are investigated. …

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Denoising Techniques - A Comparison, Sarita Veera Dangeti Jan 2003

Denoising Techniques - A Comparison, Sarita Veera Dangeti

LSU Master's Theses

Visual information transmitted in the form of digital images is becoming a major method of communication in the modern age, but the image obtained after transmission is often corrupted with noise. The received image needs processing before it can be used in applications. Image denoising involves the manipulation of the image data to produce a visually high quality image. This thesis reviews the existing denoising algorithms, such as filtering approach, wavelet based approach, and multifractal approach, and performs their comparative study. Different noise models including additive and multiplicative types are used. They include Gaussian noise, salt and pepper noise, speckle …

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Traffic Engineering In Multiprotocol Label Switching Networks, Chung-Yu Wei Jan 2003

Traffic Engineering In Multiprotocol Label Switching Networks, Chung-Yu Wei

LSU Master's Theses

The goal of Traffic Engineering is to optimize the resource utilization and increase the network performance. Constraint-based routing has been proposed as an networks effective approach to implement traffic engineering in Multiprotocol Label Switching. In this thesis, we review several algorithms on constraint-based routing from the literature and point out their advantages and disadvantages. We then propose several algorithms to overcome some of the shortcomings of these approaches. Our algorithms are specifically suitable for large densely connected networks supporting both Quality of Service traffic and the Best Effort traffic. In large networks the size of the MPLS label space in …

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Evaluation Of Mechanical Fitness For Service Of High Temperature Hydrogen Attacked Steels, Brent Matthew Saba Jan 2003

Evaluation Of Mechanical Fitness For Service Of High Temperature Hydrogen Attacked Steels, Brent Matthew Saba

LSU Master's Theses

A novel approach is introduced in evaluating one of industry’s most complex corrosion phenomena, high temperature hydrogen attack (HTHA). Limited efforts have been made by industry to address this degradation mechanism and even less data are available to properly utilize their evaluation techniques. The predominant fracture mechanics based analysis of HTHA relies on Charpy V-Notch (CVN) impact test data. In the face of limited CVN test data, accurate results are shaky at best. The HTHA evaluation set forth in this paper combines the analysis tools of plastic collapse and both static and dynamic fracture mechanics. The first condition addresses plastic …

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Effect Of Unsteady Wake, Free Stream Turbulence, Tip Geometry On Blade Tip Flow And Heat Transfer, Vikrant Saxena Jan 2003

Effect Of Unsteady Wake, Free Stream Turbulence, Tip Geometry On Blade Tip Flow And Heat Transfer, Vikrant Saxena

LSU Master's Theses

A comprehensive investigation of the effect of various tip sealing geometries is presented on the blade tip leakage flow and associated heat transfer. The linear cascade is made of four blades scaled up HPT turbine in a low speed wind tunnel facility with the two corner blades acting as guides. The tip section of a HPT first stage rotor blade is used to fabricate the 2-D blade. The wind tunnel accommodates an 116 degree turn in the flow through the blade cascade. The mainstream Reynolds number based on the axial chord length at cascade exit is 4.83e5. The center blade …

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