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2003

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Articles 1741 - 1770 of 2071

Full-Text Articles in Engineering

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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Adsorption Of Aromatic Hydrocarbons At Gas-Water Interface, Suresh Raja Jan 2003

Adsorption Of Aromatic Hydrocarbons At Gas-Water Interface, Suresh Raja

LSU Master's Theses

Adsorption of organic vapors at a gas-water interface has several physical applications with respect to natural processes in the environment. Understanding the adsorption processes is critical in development of risk assessment and modeling of transport and fate of various chemical species that are abundantly present in the environment. Evidences from the works of several researchers point out deviations in gas-liquid partitioning as predicted by Henry’s law. In view of several theories that describe these deviations, adsorption process is hypothesized to be significant in gas-liquid partitioning, in addition to temperature and presence of organic matter, particularly on liquid surfaces with high …

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An Experimental Study Of The Applicability Of Flooding Phenomena To The Dynamic Lubrication Method Of Well Control, Rishi R. Ramtahal Jan 2003

An Experimental Study Of The Applicability Of Flooding Phenomena To The Dynamic Lubrication Method Of Well Control, Rishi R. Ramtahal

LSU Master's Theses

This research investigates the feasibility of the dynamic lubrication method of well control as an alternative to conventional stepwise lubrication. The applicability of flooding phenomena to dynamic lubrication and its use in an optimization method to maximize pumping rates was also investigated. An experimental approach was taken in which experiments were conducted in a 13’ long laboratory apparatus designed to emulate the geometry in a wellhead and also in a full-scale research well. The laboratory experiments were conducted to visually investigate the mechanism of flooding and derive a flooding correlation applicable to this type of system. The full-scale experiments were …

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Predictions For Multi-Scale Shock Heating Of A Granular Energetic Material, Venugopal Jogi Jan 2003

Predictions For Multi-Scale Shock Heating Of A Granular Energetic Material, Venugopal Jogi

LSU Master's Theses

This thesis addresses the multi scale heating of a granular energetic solid due to shock loading. To this end, an existing mathematical model that has been used to predict low pressure bulk and localized heating of the granular high-explosive HMX ([CH2NNO2]4) is extended to account for compressibility and melting of the pure phase solid. Dense granular HMX has a heterogeneous structure composed of randomly packed small grains (average size ~ 100 µm) having a free-pour density that is approximately 65% of the pure phase solid density. The shock loading response of this material is …

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Application Of Mechanistic Models In Predicting Flow Behavior In Deviated Wells Under Ubd Conditions, Faisal Abdullah Aladwani Jan 2003

Application Of Mechanistic Models In Predicting Flow Behavior In Deviated Wells Under Ubd Conditions, Faisal Abdullah Aladwani

LSU Master's Theses

Underbalanced drilling (UBD) has increased in recent years because of the many advantages associated with it. These include increase in the rate of penetration and reduction of lost circulation and formation damage. Drilling of deviated and horizontal wells also increased since recovery can be improved from a horizontal or a deviated well. The drilling of deviated wells using UBD method will reduce several drilling related problems such as hole cleaning and formation damage. Prediction of flow and pressure profiles while drilling underbalanced in such wells will help in designing and planning of the well. The main aim of this research …

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Efficient Embedding Of Virtual Hypercubes In Irregular Wdm Optical Networks, Guru Prasad P. Kithlanagamangala Jan 2003

Efficient Embedding Of Virtual Hypercubes In Irregular Wdm Optical Networks, Guru Prasad P. Kithlanagamangala

LSU Master's Theses

This thesis addresses one of the important issues in designing future WDM optical networks. Such networks are expected to employ an all-optical control plane for dissemination of network state information. It has recently been suggested that an efficient control plane will require non-blocking communication infrastructure and routing techniques. However, the irregular nature of most WDM networks does not lend itself to efficient non-blocking communications. It has been recently shown that hypercubes offer some very efficient non-blocking solutions for, all-to-all broadcast operations, which would be very attractive for control plane implementation. Such results can be utilized by embedding virtual structures in …

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Arithmetic Logic Unit (Alu) Design Using Reconfigurable Cmos Logic, Chandra Srinivasan Jan 2003

Arithmetic Logic Unit (Alu) Design Using Reconfigurable Cmos Logic, Chandra Srinivasan

LSU Master's Theses

Using the reconfigurable logic of multi-input floating gate MOSFETs, a 4-bit ALU has been designed for 3V operation. The ALU can perform four arithmetic and four logical operations. Multi- input floating gate (MIFG) transistors have been promising in realizing increased functionality on a chip. A multi- input floating gate MOS transistor accepts multiple inputs signals, calculates the weighted sum of all input signals and then controls the ON and OFF states of the transistor. This enhances the transistor function to more than just switching. This changes the way a logic function can be realized. Implementing a design using multi-input floating …

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Film Cooling From Cylindrical Holes In Transverse Slots, Mohammed Altorairi Jan 2003

Film Cooling From Cylindrical Holes In Transverse Slots, Mohammed Altorairi

LSU Master's Theses

In this study, heat transfer coefficient and film effectiveness distributions are investigated for a film cooling hole configuration that has inclined holes discharging into a tangential slot before interactions with the mainstream. The cylindrical holes are inclined 35° along the mainstream direction. The effect of coolant-to-mainstream blowing ratio is examined for M=0.5 and M=1.0. Different slot width to hole ratios and also the effect of hole exit condition (square edge and triangular edge) is considered. The mainstream velocity and free-stream turbulence intensity in the low speed wind tunnel are 9 m/s and 7% respectively and the mainstream Reynolds number based …

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Dechlorination Of 1,2,3,4-Tetrachlorobenzene In Organic Matter- And Mineral-Dominated Soils And Effects Of Typha Latifolia Roots, Lizhu Lin Jan 2003

Dechlorination Of 1,2,3,4-Tetrachlorobenzene In Organic Matter- And Mineral-Dominated Soils And Effects Of Typha Latifolia Roots, Lizhu Lin

LSU Master's Theses

A variety of environments are contaminated with chlorinated benzenes. Therefore, investigating the biodegradation of chlorobenzenes in different types of soils is useful in assessing the feasibility of bioremediation. One mineral-dominated soil: PPI (Petro Processors Inc. site) soil, and three organic matter-dominated soils (natural wetland soil, constructed wetland soil (a mixture of peat, compost and sand), and river sediment) were used to investigate anaerobic biodegradation of 1,2,3,4-Tetrachlorobenzene (1,2,3,4-TeCB) using laboratory microcosms. To determine whether methanogens were directly responsible for dechlorination, a comparative study using 2-bromoethanesulfonic acid (BES) for inhibition of methanogenesis was conducted. Hydrogen and methane concentrations, and microbial diversities were …

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Synthesis, Structure And Properties Of Nanolayered Dlc/Dlc Films, Pankaj Gupta Jan 2003

Synthesis, Structure And Properties Of Nanolayered Dlc/Dlc Films, Pankaj Gupta

LSU Master's Theses

Diamondlike carbon (DLC) films have been explored extensively in the past due to their highly attractive properties. However, the high level of internal stress developed during growth prevents deposition of thick films. Synthesis of DLC/DLC multilayers (DDM) presents a venue to overcome this drawback. In the present study, DLC films and DDM were deposited on Si substrate using dc plasma of CH4 and Ar gas mixture. FTIR was used to analyze the structure of the DLC films. Mechanical properties of the films were characterized by microhardness testing and nanoindentation. The tribological properties were studied by conducting pin-on-disc experiments in …

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High Strain Rate Properties Of Polymer Matrix Composites, Amol Jadhav Jan 2003

High Strain Rate Properties Of Polymer Matrix Composites, Amol Jadhav

LSU Master's Theses

The vast differences in strength, ultimate strain and modulus during high strain rate (HSR) deformation of materials have been a very long-standing subject of engineering interest. This thesis deals with characterization of mechanical properties of two composite materials, balanced angle-ply graphite epoxy laminates (fibrous composite) and syntactic foams (particulate composite). The focus of this study is to compare the mechanical properties of these composite materials at high strain rates and quasi-static conditions and to find out the effects of failure modes on HSR mechanical properties of these materials. Split Hopkinson Pressure Bar (SHPB) apparatus is used for the HSR testing …

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Exploring Geometric, Kinematic And Behavioral Scalability Of Microscopic Traffic Simulation Systems, Srikanth Chakravarthy Jan 2003

Exploring Geometric, Kinematic And Behavioral Scalability Of Microscopic Traffic Simulation Systems, Srikanth Chakravarthy

LSU Master's Theses

Even with today's remarkable advancement in computing power, microscopic simulation modeling remains a computationally intensive process that imposes limitations on its potential use for modeling large-scale transportation networks. Research and practice have repeatedly demonstrated that microscopic simulation runs can be excessively time-consuming, depending on the network size, the number of simulated entities (vehicles), and the computational resources available. While microscopic features of a simulated system collectively define the overall system characteristics, it is argued that the microscopic simulation process itself is not necessarily free of redundancy, which if reduced, could substantially improve the computational efficiency of simulation systems without compromising …

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