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2013

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Spectral Breast Ct : Effect Of Adaptive Filtration On Ct Numbers, Ct Noise, And Ct Dose, Justin Silkwood Jan 2013

Spectral Breast Ct : Effect Of Adaptive Filtration On Ct Numbers, Ct Noise, And Ct Dose, Justin Silkwood

LSU Master's Theses

Purpose: Adaptive filtration facilitates spectral breast CT by decreasing count rate and dynamic range requirements of photon counting detectors. This project investigated the effect of adaptive filtration on beam hardening, CT numbers, noise, and dose in dedicated breast CT. Methods: Adaptive filters were simulated to provide a flat fluence at the detector surface when used with a 14 cm breast phantom at 120 kVp. Beam hardening with each filter type was measured against increasing x-ray beam half-fan angle.. Breast CT images were simulated with and without an adaptive filter in the beam at multiple tube voltages. CT number, noise, and …

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High Resolution Tephra And U/Pb Chronology Of The 3.33 – 3.26 Ga Mendon Formation, Barberton, Greenstone Belt, South Africa, Nicholas Burns Decker Jan 2013

High Resolution Tephra And U/Pb Chronology Of The 3.33 – 3.26 Ga Mendon Formation, Barberton, Greenstone Belt, South Africa, Nicholas Burns Decker

LSU Master's Theses

The Mendon Formation in the Barberton Greenstone Belt of South Africa marks the boundary between the Onverwacht and Fig Tree Groups. These groups are characterized by mafic to ultramafic volcanism and felsic volcanism with related epiclastic sedimentation, respectively. This transition marks the end of komatiitic volcanism in the Barberton Greenstone Belt and is accompanied by numerous impact-related spherule layers. This study characterizes the upper Mendon Formation texturally and geochemically over a wide areal extent and across structure and facies change in an attempt to better understand the evolution of tectonic processes at this boundary. A suite of whole rock and …

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Differentiation Of Voice Disorders Using Objective Parameters From Harmonic Waveform Modeling In High-Speed Digital Imaging, Aimee Elaine Perkins Jan 2013

Differentiation Of Voice Disorders Using Objective Parameters From Harmonic Waveform Modeling In High-Speed Digital Imaging, Aimee Elaine Perkins

LSU Master's Theses

High-speed digital imaging (HSDI) has recently become clinically available for the direct observation of vocal fold movement in the last 20 years. However, before it can become routinely used in the clinical setting, a universal means of objectively analyzing and interpreting the HSDI data must be established. In this study, preliminary data was gathered for five parameters used to objectively analyze vocal fold vibratory patterns observed with HSDI. The parameters investigated were established by Ikuma, Kunduk, and McWhorter (2012a) and were previously studied with a small sample (N=8) comparing pre and post-phonosurgical removal of benign lesions. The five parameters included …

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A Preliminary Investigation Of The Demographic, Systematic Risk, And Systematic Promotive Factors That Influence Higher Educational Attainment Among Foster Care Youths And Young Adults Who Age Out Of The Foster Care System, Dana R. Hunter Jan 2013

A Preliminary Investigation Of The Demographic, Systematic Risk, And Systematic Promotive Factors That Influence Higher Educational Attainment Among Foster Care Youths And Young Adults Who Age Out Of The Foster Care System, Dana R. Hunter

LSU Doctoral Dissertations

The purpose of this explanatory-descriptive study was to investigate the demographic, systematic risk, and systematic promotive factors that best predicted higher educational attainment among foster care youths and young adults who exit the foster care system. The researcher conducted a secondary data analysis on National Youth in Transition Data (NYTD) and child welfare administrative data collected by a child welfare agency in the southern region of the United States. The survey participants in this study consisted of a sample of 1,266 current foster care youths and 157 young adults who aged out of care between the ages of 14 and …

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Subsurface Stratigraphic Architecture Of Pleistocene Sediments In The Greater New Orleans Area, James Ayrer Jan 2013

Subsurface Stratigraphic Architecture Of Pleistocene Sediments In The Greater New Orleans Area, James Ayrer

LSU Master's Theses

A major environmental and economic problem currently faces the New Orleans area, in southeastern Louisiana, stemming from salinization of freshwater aquifers that are important resources for the community. Major pumping of these aquifers has altered the potentiometric flow, allowing saltier bodies of water to flow into the region. The impact of pumping wells on encroachment of saltwater and the time as well as the route for saltwater to travel from the current saltwater-freshwater interface to pumping centers is not well constrained. Water planners need additional information to make decisions about future management of groundwater resources. The most effective way to …

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Complexity-Driven Properties Of The Intermetallic Compounds Gd₁₁₇Co₅₆Sn₁₁₂ And Ln₃₀Ru₄Sn₃₁ (Ln = Gd And Tb), Devin Charles Schmitt Jan 2013

Complexity-Driven Properties Of The Intermetallic Compounds Gd₁₁₇Co₅₆Sn₁₁₂ And Ln₃₀Ru₄Sn₃₁ (Ln = Gd And Tb), Devin Charles Schmitt

LSU Doctoral Dissertations

Understanding the relationships between the structure of materials and their properties in extended solid systems is a necessity when intuitively designing functional materials. One of the most fundamental properties of a material is its ability to transport heat, which is linked to the lattice complexity of the material. Here, the single crystalline materials Gd117Co56Sn112 and Tb30Ru4Sn31 are grown to study the pronounced effect of a complexity-driven reduction of lattice thermal conductivity. The transport and magnetic properties of Gd117Co56Sn112 and Ln30Ru4Sn31 (Ln = Gd and Tb) are also presented and related to other systems. Tb30Ru4Sn31 is found to be a large …

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Geometric Modeling And Optimization Over Regular Domains For Graphics And Visual Computing, Shenghua Wan Jan 2013

Geometric Modeling And Optimization Over Regular Domains For Graphics And Visual Computing, Shenghua Wan

LSU Doctoral Dissertations

The effective construction of parametric representation of complicated geometric objects can facilitate many design, analysis, and simulation tasks in Computer-Aided Design (CAD), Computer-Aided Manufacturing (CAM), and Computer-Aided Engineering (CAE). Given a 3D shape, the procedure of finding such a parametric representation upon a canonical domain is called geometric parameterization. Regular geometric regions, such as polycubes and spheres, are desirable domains for parameterization. Parametric representations defined upon regular geometric domains have many desirable mathematical properties and can facilitate or simplify various surface/solid modeling and processing computation. This dissertation studies the construction of parameterization on regular geometric domains and explores their applications …

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Exploring The Learnability Of Numeric Datasets, Di Lin Jan 2013

Exploring The Learnability Of Numeric Datasets, Di Lin

LSU Doctoral Dissertations

When doing classification, it has often been observed that datasets may exhibit different levels of difficulty with respect to how accurately they can be classified. That is, there are some datasets which can be classified very accurately by many classification algorithms, and there also exist some other datasets that no classifier can classify them with high accuracy. Based on this observation, we try to address the following problems: a)what are the factors that make a dataset easy or difficult to be accurately classified? b) how to use such factors to predict the difficulties of unclassified datasets? and c) how to …

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Finite Element Methods For Fourth Order Variational Inequalities, Yi Zhang Jan 2013

Finite Element Methods For Fourth Order Variational Inequalities, Yi Zhang

LSU Doctoral Dissertations

In this work we study finite element methods for fourth order variational inequalities. We begin with two model problems that lead to fourth order obstacle problems and a brief survey of finite element methods for these problems. Then we review the fundamental results including Sobolev spaces, existence and uniqueness results of variational inequalities, regularity results for biharmonic problems and fourth order obstacle problems, and finite element methods for the biharmonic problem. In Chapter 2 we also include three types of enriching operators which are useful in the convergence analysis. In Chapter 3 we study finite element methods for the displacement …

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Long-Term Total Suspended Sediment Yield Of Coastal Louisiana Rivers With Spatiotemporal Analysis Of The Atchafalaya River Basin And Delta Complex, Timothy Rosen Jan 2013

Long-Term Total Suspended Sediment Yield Of Coastal Louisiana Rivers With Spatiotemporal Analysis Of The Atchafalaya River Basin And Delta Complex, Timothy Rosen

LSU Master's Theses

The modern day Mississippi River Delta Plain and the Louisiana Chenier Plain have been greatly altered through anthropogenic changes to course and hydrological conditions of the Mississippi River and local rivers, most notably by levees that have excluded the Mississippi River from the delta plain. This has slowed accretion and increased land loss destroying vast quantities of marsh, endangering many coastal communities. This master’s thesis examined long-term total suspended sediment yield of four Chenier Plain rivers, total suspended sediment yield of the Mississippi River under different flow conditions, and total suspended sediment dynamics of the Atchafalaya River in relation to …

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Effects Of Predator Reduction On Nest Success Of Upland Nesting Ducks In Low-Grassland Density Landscapes In Eastern North Dakota, Michael Buxton Jan 2013

Effects Of Predator Reduction On Nest Success Of Upland Nesting Ducks In Low-Grassland Density Landscapes In Eastern North Dakota, Michael Buxton

LSU Master's Theses

Nest success of upland nesting ducks is the primary driver of duck population growth in the Prairie Pothole Region. Nest success is greatly influenced by nest predation and the amount of available nesting cover on the landscape. The decline in acres enrolled in the Conservation Reserve Program (CRP) in this region has negatively impacted the amount of available nesting cover, making nesting cover sparse and confined to small patches where predation rates are potentially elevated. I evaluated the efficacy of seasonal predator reduction on increasing nest success on low-grassland density (>10% grassland cover), 93 km2 landscapes in two different …

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Heterogeneous Volumetric Data Mapping And Its Medical Applications, Huanhuan Xu Jan 2013

Heterogeneous Volumetric Data Mapping And Its Medical Applications, Huanhuan Xu

LSU Doctoral Dissertations

With the advance of data acquisition techniques, massive solid geometries are being collected routinely in scientific tasks, these complex and unstructured data need to be effectively correlated for various processing and analysis. Volumetric mapping solves bijective low-distortion correspondence between/among 3D geometric data, and can serve as an important preprocessing step in many tasks in compute-aided design and analysis, industrial manufacturing, medical image analysis, to name a few. This dissertation studied two important volumetric mapping problems: the mapping of heterogeneous volumes (with nonuniform inner structures/layers) and the mapping of sequential dynamic volumes. To effectively handle heterogeneous volumes, first, we studied the …

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Development Of Watershed-Based Modeling Approach To Pollution Source Identification, Yangbin Tong Jan 2013

Development Of Watershed-Based Modeling Approach To Pollution Source Identification, Yangbin Tong

LSU Master's Theses

Identification of unknown pollution sources is essential to environmental protection and emergency response. A review of recent publications in source identification revealed that there are very limited numbers of research in modeling methods for rivers. What’s more, the majority of these attempts were to find the source strength and release time, while only a few of them discussed how to identify source locations. Comparisons of these works indicated that a combination of biological, mathematical and geographical method could effectively identify unknown source area(s), which was a more practical trial in a watershed. This thesis presents a watershed-based modeling approach to …

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Studies Of Core-Shell Nanogumbos And Liposomal Ionogels, Ashleigh Renee' Wright Jan 2013

Studies Of Core-Shell Nanogumbos And Liposomal Ionogels, Ashleigh Renee' Wright

LSU Doctoral Dissertations

The work presented in this dissertation is a description of novel core-shell nanomaterials derived from a group of uniform materials based on organic salts (GUMBOS) and the synthesis and characterizations of novel liposomal ionogels (LIGs). These GUMBOS are an extension of ionic liquids (ILs) which are organic salts with melting points between 25 °C and 100 °C. Ionic liquids have high thermal stability, low vapor pressure, and tunable physiochemical and functional properties. All of the properties of ILs are controlled by the chosen cation and anion pair. Similarly to ILs, GUMBOS possess the same qualities; however, they have melting points …

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Fast And Reliable Detection Of Incumbent Users In Cognitive Radios, Mahdi Orooji Jan 2013

Fast And Reliable Detection Of Incumbent Users In Cognitive Radios, Mahdi Orooji

LSU Doctoral Dissertations

Fast and reliable Spectrum Sensing (SS) plays a crucial role in the cognitive radio (CR) technology in order to prevent unwanted interference to the primary users (PU) and to reliably and quickly detect the white spaces in the spectrum for opportunistic access by the secondary users (SU). Spectrum Sensing must often be performed in the absence of information such as PU signaling scheme, noise level and channel fading coefficients. While these parameters can be estimated in the SU, estimation errors significantly deteriorates the performance of SS techniques. In this thesis, we introduce and evaluate the performance of two novel blind …

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Cyclic Block Copolypeptoids : Synthesis, Self-Assembly And Macroscopic Properties, Chang-Uk Lee Jan 2013

Cyclic Block Copolypeptoids : Synthesis, Self-Assembly And Macroscopic Properties, Chang-Uk Lee

LSU Doctoral Dissertations

This dissertation presents the first experimental efforts for synthesizing a new class of peptidomimetic polymers, cyclic block copolypeptoids, studying their self-assembly in dilute solution, and examining their macroscopic properties. Cyclic poly(N-methyl-glycine)-b-poly(N-decyl-glycine) (PNMG-b-PNDG) diblock copolymers were synthesized via sequential, N-heterocyclic carbene (NHC)-mediated ring-opening polymerization of NCA monomers with controlled chain length and compositions. Cryo-TEM shows that PNMG105-b-PNDG10 copolymers in methanol (1 mg/mL) form spherical micelles that organize to form cylindrical micelles over time. The formation of cylindrical micelles is attributed to the crystallization of PNDG chains, as revealed by SAED and microDSC analyses. Cyclic PNMG100-b-PNDG10 copolymers form thermo-reversible, free-standing gels at …

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The Ring Theory And The Representation Theory Of Quantum Schubert Cells, Joel Benjamin Geiger Jan 2013

The Ring Theory And The Representation Theory Of Quantum Schubert Cells, Joel Benjamin Geiger

LSU Doctoral Dissertations

In recent years the quantum Schubert cell algebras, introduced by Lusztig and De Concini--Kac, and Procesi, have garnered much interest as this versatile class of objects are furtive testing grounds for noncommutative algebraic geometry. We unify the two main approaches to analyzing the structure of the torus-invariant prime spectra of quantum Schubert cell algebras, a ring theoretic one via Cauchon's deleting derivations and a representation theoretic characterization of Yakimov via Demazure modules. As a result one can combine the strengths of the two approaches. In unifying the theories, we resolve two questions of Cauchon and Mériaux, one of which involves …

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Mathematical And Computer-Based Models For Optimizing Microwave Heating Processes Of Frozen Oysters, Jie Zhang Jan 2013

Mathematical And Computer-Based Models For Optimizing Microwave Heating Processes Of Frozen Oysters, Jie Zhang

LSU Doctoral Dissertations

Consumers with full-time jobs prefer microwavable-frozen-meals for convenience when lack time to cook. Microwaves do not require a medium for heat transfer and provide quick heating even in low thermal conductivity foods, which does not occur in conventional heating. The main problem in utilizing microwave-heating for cooking is the non-uniform temperature distribution in foods which may result in insufficient lethality of microorganisms in some part. This non-uniformity can be due to a number of factors including composition and geometry of food. The objectives of this study were to develop a mathematical-model based on Maxwell¡¯s equations for predicting the temperature distribution …

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A Study Of The Temporal And Spatial Distribution Of Ichthyoplankton And Post-Larval Penaeids Recruiting Into A Louisiana Tidal Pass, Matthew John Kupchik Jan 2013

A Study Of The Temporal And Spatial Distribution Of Ichthyoplankton And Post-Larval Penaeids Recruiting Into A Louisiana Tidal Pass, Matthew John Kupchik

LSU Doctoral Dissertations

This dissertation attempts to better understand astronomical, meteorological, and oceanographic forcing of offshore-spawned, estuarine-dependent species from continental shelf to estuarine waters through tidal passes. The vertical distribution of zoo-/ichthyoplankton within the inner continental shelf from the Louisiana Offshore Oil Platform monitoring project (1978-1995) provided an important offshore end member for the estuarine recruitment study, and is potentially useful in predicting vulnerabilities to past and future oil spills. The role that atmospheric cold front passages may have on densities and movement of zoo-/ichthyoplankton recruiting through the Bayou Tartellan tidal pass, Louisiana, were analyzed using a Generalized Additive Model. The pre-frontal phase, …

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Fluorescent Materials For Chemical Sensing, Brian Gerard Imsick Jan 2013

Fluorescent Materials For Chemical Sensing, Brian Gerard Imsick

LSU Doctoral Dissertations

Materials incorporating fluorescent π-electron conjugated molecular species for sensing and imaging are advantageous over other detection or identification methods such as colorimetric reporters. Fluorescent materials offer easy recognition of binding events due to the highly sensitive nature of fluorescence techniques down to the single molecule level. The properties of fluorescent molecules allow for rapid attenuation of observable readout due to the facile transport of excited state energy via both inter- and intramolecular pathways. This dissertation primarily focused on the development and study of a general platform for ratiometric fluorescent chemosensing using surface-immobilized oligomers, as well as in depth explorations of …

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Bear With Me : Signs Are Tricksters, And Reality Is Invisible To The Naked Eye: A One-Person Play, Chia-Wen Hsu Jan 2013

Bear With Me : Signs Are Tricksters, And Reality Is Invisible To The Naked Eye: A One-Person Play, Chia-Wen Hsu

LSU Master's Theses

The creation of a one-person play is required in order to complete the Master of Fine Arts degree in acting. There are no official guidelines, only twenty to forty minutes in length is required. Although I was very excited about receiving the challenge, I did not breathe a sigh of relief until I found the topic I wanted to explore－Signs and Reality, and the one-person play that followed: Bear With Me. Since I am not a native English speaker, I have been frustrated by miscommunication through words in the English-speaking world, which gave me the eagerness to talk about the …

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Spatial Variations In Salinity And Temperature Around The Bay Marchand Salt Dome, Offshore Louisiana, Laurie Richards Jan 2013

Spatial Variations In Salinity And Temperature Around The Bay Marchand Salt Dome, Offshore Louisiana, Laurie Richards

LSU Master's Theses

The Bay Marchand field is located about 60 miles south of New Orleans, Louisiana on the continental shelf. The structurally complex field has produced over 960 MMBOE as of 2012 (http://www.eplweb.com), with many of these hydrocarbons being trapped against the massive salt dome and associated faulting present in the area. A study by Bruno and Hanor (2003) documented the presence of a high salinity plume off the southeast flank of the dome that had less saline and less dense pore water below it. The purpose of this study was to investigate the spatial variations in pore water salinity and temperature …

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Hydraulic Fracturing And Water Use In Dallas, Texas, Sarah Yates Jan 2013

Hydraulic Fracturing And Water Use In Dallas, Texas, Sarah Yates

LSU Master's Theses

Dallas, Texas is located in North Texas and sits above the eastern portion of the Barnett Shale natural gas formation. Hydraulic fracturing, or “fracking”, was introduced to the region as a means to access previously inaccessible natural gas within the formation. This fracking concerns many because it requires large amounts of fresh water, an average of over 4 million gallons per well within Dallas Water Utilities’ service area. This thesis examines whether water use for fracking will have a negative effect on the water supply for the city of Dallas and its wholesale water customer cities. The water is typically …

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Treatment Integrity Failures Matched To Behavioral Function, Joanna Elizabeth Lomas Mevers Jan 2013

Treatment Integrity Failures Matched To Behavioral Function, Joanna Elizabeth Lomas Mevers

LSU Doctoral Dissertations

Prior research on treatment integrity has focused on either the lack of measurement of the independent variable (Peterson, Homer & Wonderlich, 1982; Gresham, Gansle & Noel, 1993; Wheeler, Baggett, Fox & Blevins, 2006; McIntyre, Gresham, DiGennaro & Reed, 2007; Sanetti, Gritter & Dobey, 2011) or on methods to increase overall levels of treatment integrity(Witt, Noell, LaFleur & Mortenson, 1997; Noell, Witt, Gilbertson, Ranier & Freeland,1997; Noell et al., 2005). Yet little research has been devoted to understanding the effectiveness of common interventions when those interventions are implemented with less than perfect integrity. The current investigation evaluated the effectiveness of using …

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Reciprocal Peer Mentoring : Increasing The Prosocial Behavior Of Socially Neglected Students, Tai A. Collins Jan 2013

Reciprocal Peer Mentoring : Increasing The Prosocial Behavior Of Socially Neglected Students, Tai A. Collins

LSU Doctoral Dissertations

Two studies investigated the effectiveness of the Reciprocal Peer Mentoring intervention in improving the prosocial behavior of socially neglected elementary school students as measured by a Direct Behavior Rating filled out by their teachers. Reciprocal Peer Mentoring uses the methodological framework of the Check-In/Check-Out intervention (e.g. Hawken & Horner, 2003), but expands on it by using peers as mentors, adding a reciprocity component, focusing on prosocial behavior, and targeting socially neglected students. In Study 1, the effectiveness of Nonreciprocal Peer Mentoring was examined, as popular peers served as mentors for neglected peers. In Study 2, neglected or rejected students mentored …

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Quantification Of Total And Oil-Degrading Bacteria In Louisiana Marsh Sediment Following The Deepwater Horizon Oil Spill Using Cultivation And Real-Time Pcr Assays, Kristopher Nolan Ackoury Jan 2013

Quantification Of Total And Oil-Degrading Bacteria In Louisiana Marsh Sediment Following The Deepwater Horizon Oil Spill Using Cultivation And Real-Time Pcr Assays, Kristopher Nolan Ackoury

LSU Master's Theses

Although the impacts of the Deepwater Horizon (DWH) oil spill on the bacterial communities in several Gulf of Mexico habitats have been described, little if any research has been published evaluating the impacts of the spill on bacterial populations in the most severely oiled salt marsh soils of Barataria Bay, Louisiana. The aim of this study was to define the effects of the spill on the total and oil-degrading bacterial communities in these marshes. Using quantitative real-time PCR (qPCR) and traditional cultivation methods bacterial communities from contaminated marsh soils were examined thirteen, twenty-two, and twenty-nine months after the initial oiling …

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Evaluation Of An Automated Delivery Verification System For Volumetric Modulated Arc Therapy Treatments, John-Paul Grenier Jan 2013

Evaluation Of An Automated Delivery Verification System For Volumetric Modulated Arc Therapy Treatments, John-Paul Grenier

LSU Master's Theses

Purpose: The purpose of this work was to evaluate the ability of a treatment delivery verification system to detect clinically significant mechanical errors in VMAT delivery utilizing data contained within a commercial record and verify (RV) system, and to test whether the system can be used to reconstruct dose distributions that agree more closely with measured dose distributions than do the original treatment plans. Methods: VMAT treatment plans from five prostate patients, five head and neck patients, and five post-mastectomy chest wall patients treated at our clinic were selected for this study. Known mechanical errors were introduced into each plan, …

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Evaluation Of Thermal Insulation By Coal Beds In The Western Arkoma Basin, Ok And Implications For Large Scale Geothermal Resources, Matthew Freeman Jan 2013

Evaluation Of Thermal Insulation By Coal Beds In The Western Arkoma Basin, Ok And Implications For Large Scale Geothermal Resources, Matthew Freeman

LSU Master's Theses

Weighted average geothermal gradients in the Western Arkoma Basin, Oklahoma are estimated from bottom hole temperatures (BHT) from 158 oil and gas wells. The regional geothermal gradient is 28.8 °C/km. The central and north central portions of the basin have higher gradients than southern and northern portions, especially in large areas of Pittsburg and Haskell counties where geothermal gradients in excess of 36 °C/km exist. These gradients suggest that temperatures suitable for low temperature geothermal power exist at depths of 2-3 km. Coals have very low thermal conductivity (0.15 – 0.5 W/m°K) acting as thermal insulators. This study examines the …

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The Development Of An Ac Magneto- Optic Kerr Effect System For The Characterization Of Pulsed Laser Deposited Co₂Mnsi-Xal1-X Heusler Alloy Thin Films, Matthew Stephen Champagne Jan 2013

The Development Of An Ac Magneto- Optic Kerr Effect System For The Characterization Of Pulsed Laser Deposited Co₂Mnsi-Xal1-X Heusler Alloy Thin Films, Matthew Stephen Champagne

LSU Master's Theses

The Kerr rotation and Kerr ellipticity of thin films can be measured using an AC magneto-optic Kerr effect (AC-MOKE) system. The longitudinal MOKE measurements were taken for a series of Co2MnSixAl1-x thin films with values of x= 0.00, 0.25, 0.50, 0.75, 1.00. The films were fabricated using ultra high vacuum, pulsed laser deposition (PLD) techniques. The PLD targets were made using conventional arc-melting techniques. Using a Jones matrix analysis, it was shown that the Kerr rotation and Kerr ellipticity can be measured separately using two optical setups by taking advantage of a photoelastic modulator and lock-in techniques. Co2MnAl and Co2MnSi …

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Adaptive Stochastic Conjugate Gradient Optimization For Temporal Medical Image Registration, Huanhuan Xu Jan 2013

Adaptive Stochastic Conjugate Gradient Optimization For Temporal Medical Image Registration, Huanhuan Xu

LSU Master's Theses

We propose an Adaptive Stochastic Conjugate Gradient (ASCG) optimization algorithm for temporal medical image registration. This method combines the advantages of Conjugate Gradient (CG) method and Adaptive Stochastic Gradient Descent (ASGD) method. The main idea is that the search direction of ASGD is replaced by stochastic approximations of the conjugate gradient of the cost function. In addition, the step size of ASCG is based on the approximation of the Lipschitz constant of the stochastic gradient function. Thus, this algorithm could maintain the good properties of the conjugate gradient method, meanwhile it uses less gradient computation time per iteration and adjusts …

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