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Articles 2191 - 2220 of 3417

Full-Text Articles in Physical Sciences and Mathematics

Gamma Ray Burst Redshift Catalog And Applications, Limin Xiao Jan 2010

Gamma Ray Burst Redshift Catalog And Applications, Limin Xiao

LSU Doctoral Dissertations

The measurement of redshifts for gamma-ray bursts (GRBs) is an important issue for the study of the high redshift universe and cosmology. We developed a program to estimate the redshifts for GRBs from the original light curves and spectra, aiming to get redshifts for bursts without spectroscopic or photometric redshifts. We derive the luminosity indicators from the light curves and spectra of each burst, including the lag time between low and high photon energy light curves, the variability of the light curve, the peak energy of the spectrum, the number of peaks in the light curve, and the minimum rise …

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Generalized Curvilinear Advection Formalism For Finite Volume Codes Doing Relativistic Hydrodynamics, Jay Michael Call Jan 2010

Generalized Curvilinear Advection Formalism For Finite Volume Codes Doing Relativistic Hydrodynamics, Jay Michael Call

LSU Doctoral Dissertations

While it is possible to numerically evolve the relativistic fluid equations using any chosen coordinate mesh, typically there are distinct computational advantages associated with different types of candidate grids. For example, astrophysical flows that are governed by rotation tend to give rise to advection variables that are naturally conserved when a cylindrical mesh is used. On the other hand, Cartesian-like coordinates afford a more straightforward implementation of adaptive mesh refinement (AMR) and avoid the appearance of coordinate singularities. Here it is shown that it should be possible to reap the benefits associated with multiple types of coordinate systems simultaneously in …

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Edaphic And Vegetative Controls On Mercury Cycling In Oligohaline Wetlands, Jonathan M. Willis Jan 2010

Edaphic And Vegetative Controls On Mercury Cycling In Oligohaline Wetlands, Jonathan M. Willis

LSU Doctoral Dissertations

With the expansion of the human population and associated industries there is a concomitant increase in both resource utilization and the production of waste and deleterious by-products. Mercury is a naturally-occurring toxic metal with a complicated and unique biogeochemical cycle, and is often a contaminant of ecotoxicological concern in unindustrialized aquatic habitats. The research described herein was designed to elucidate multiple aspects regarding the behavior of mercury in oligohaline wetland habitats, particularly with respect to edaphic and vegetative effects, through a monitoring and characterization study as well as a series of manipulative experiments. The observational study, conducted in the wetlands …

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Optimal Control And Nonlinear Programming, Qingxia Li Jan 2010

Optimal Control And Nonlinear Programming, Qingxia Li

LSU Doctoral Dissertations

In this thesis, we have two distinct but related subjects: optimal control and nonlinear programming. In the first part of this thesis, we prove that the value function, propagated from initial or terminal costs, and constraints, in the form of a differential equation, satisfy a subgradient form of the Hamilton-Jacobi equation in which the Hamiltonian is measurable with respect to time. In the second part of this thesis, we first construct a concrete example to demonstrate conjugate duality theory in vector optimization as developed by Tanino. We also define the normal cones corresponding to Tanino's concept of the subgradient of …

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Palynological Analysis Of Tiger And Trinity Shoals, Louisiana Continental Shelf, Russell Ryan Crouch Jan 2010

Palynological Analysis Of Tiger And Trinity Shoals, Louisiana Continental Shelf, Russell Ryan Crouch

LSU Master's Theses

Forty sediment samples taken from twenty-six vibracores collected from Holocene shoals (Tiger and Trinity) were processed for palynomorphs and analyzed to characterize the terrestrial and marine paleo-environments of southern Louisiana at the time of deposition of each shoal. Abundant and diverse pollen assemblages were recovered while marine microplankton were sparse (< 2% relative abundance). Pollen species were grouped by plants of similar environmental significances including arboreal, non-arboreal, aquatic, and shrub categories. Palynological signals were compared in detail between each core, as well as along strike and dip transects, to help determine whether or not these shoals were deposited coevally or in distinct depositional cycles. Evidence shows that Tiger and Trinity Shoals carry remarkably similar palynological profiles, indicating that sediments of these shoals areS from the same source, and that deposition extended over an interval of time such that climate change was not sufficient enough to alter the vegetation response (hence palynological signal). Pollen profiles show source sediments are predominantly from the lower Mississippi River drainage basin and exhibit species similar to those present in modern Louisiana coastal marshes and swamps (i.e., Taxodium distichum, Cyperaceae, Graminae, Chenopodiaceae, and Asteraceae), and coastal to upland hardwood forests of the Mississippi River alluvial valley (i.e., Pinus, Quercus, Carya, and Liquidambar styraciflua).

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Is A Student's Conceptual Knowledge Affected By Their Vocabulary Instruction?, Daniel C. Cox Jan 2010

Is A Student's Conceptual Knowledge Affected By Their Vocabulary Instruction?, Daniel C. Cox

LSU Master's Theses

The following paper explores the possible relationship between the manner in which a student is taught vocabulary in a high school physics classroom and the ability of those students to correctly answer physics conceptual questions. Two high school physics classes taught by the same teacher (eight or nine students in one and seventeen in the other) received identical instruction throughout multiple units with the exception of vocabulary instruction. Differences were observed in the students’ ability to correctly answer conceptual questions in only one topic, heat. The students did not get better at answering a question concerning a phase change or …

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Getting Off The Ground With Ap Calculus, David Frank Woods Jan 2010

Getting Off The Ground With Ap Calculus, David Frank Woods

LSU Master's Theses

“The study of mathematics, like the Nile, begins in minuteness but ends in magnificence.” – Charles Caleb Colton Caught in a downward spiral, American mathematical students continue to be outperformed by their international peers as reported by the TIMSS. This has left educators scrambling to find an instructional strategy that will slow this decline in mathematical literacy. This thesis reports on the framework that a new teacher could use to develop and establish a successful AP Calculus program, while increasing mathematical literacy, equity in the classroom, and student achievement through the integration of educational technology into current instructional trends. This …

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Integration Of Paleotempestology With Coastal Risk And Vulnerability Assessment: Case Studies From The Dominican Republic And Nicaragua, Devyani Kar Jan 2010

Integration Of Paleotempestology With Coastal Risk And Vulnerability Assessment: Case Studies From The Dominican Republic And Nicaragua, Devyani Kar

LSU Doctoral Dissertations

Hurricanes account for a significant portion of damages, injuries, and fatalities in the Caribbean. The Dominican Republic has had 3 major hurricane strikes in this century resulting in loss of lives for thousands of people and billions of US $ in economic loss. Major hurricanes had been relatively infrequent in north-eastern Nicaragua’s modern history until Hurricane Felix, a Category 5 storm, made landfall in the north-east in 2007. It caused 130 confirmed deaths and brought devastation to many villages. These events highlight a need for re-evaluation of hurricane risk based on a more comprehensive and long-term hurricane history. Using paleotempestological …

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Copula And Default Correlation, Dongxiang Yan Jan 2010

Copula And Default Correlation, Dongxiang Yan

LSU Master's Theses

This work presents a study of copulas, with special focus on the Gaussian copula model and its behavior under a certain conditioning process. Simulations are carried out to examine the behavior of the moments on conditional copula model, as measured by the behavior of Wick identities which hold for multivariate Gaussians.

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The Influences Of Microbial Diversity On Carbonate Geochemistry Across A Transition From Fresh To Saline Water In The Edwards Aquifer, Texas, Cassie Jo Gray Jan 2010

The Influences Of Microbial Diversity On Carbonate Geochemistry Across A Transition From Fresh To Saline Water In The Edwards Aquifer, Texas, Cassie Jo Gray

LSU Master's Theses

Microbially-mediated karstification through the production of metabolic byproducts has been well-documented in cave environments, but less is known about deep karstic settings. This research aimed to distinguish between microbial and geochemical influences on carbonate dissolution in the Edwards Aquifer, a prolific karst aquifer in central Texas, specifically from a transect of six wells across a transition from fresh to saline water in New Braunfels. For the first time, a portion of the aquifer’s bacterial diversity was examined from molecular 16S rRNA gene sequence analyses, which revealed that Alphaproteobacteria, Gammaproteobacteria, and Betaproteobacteria dominated the aquifer, with rare Bacteroidetes, Nitrospirae, and Firmicutes …

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Seventh-Grade Curriculum In Probability (A Guide For Teachers), David Nganga Njenga Jan 2010

Seventh-Grade Curriculum In Probability (A Guide For Teachers), David Nganga Njenga

LSU Master's Theses

A review of the literature indicates that teachers try to make connections between experimental and theoretical probabilities while teaching their students, but these connections are often not very clear. This greatly increases misconceptions students have about probability. This thesis presents a treatment of teaching probability that is geared for seventh grade and intended to minimize the misconceptions that both teachers and students may have. We present a concise mathematical exposition of finite probability models as well as collection of examples and activities, so as to help teachers and students organize their thinking and minimize misconceptions. The various examples and activities …

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Accuracy Of Srs Dose Delivery Using The Tomotherapy Hi-Art System, Catherine Leigh Batte Jan 2010

Accuracy Of Srs Dose Delivery Using The Tomotherapy Hi-Art System, Catherine Leigh Batte

LSU Master's Theses

Purpose: To quantify the accuracy and precision of both target positioning and dose delivery for intracranial radiosurgery delivered with the TomoTherapy Hi-Art System using a non-invasive immobilization device. Methods: Techniques developed by Vinci et al (2007) were refined for the measurement of dose distributions in each principal plane using a CIRS head phantom. Pieces of Gafchromic EBT2 film were cut and digitized using a template developed by Vinci et al (2007). A plan was created for a 2 cm diameter x 2 cm long cylindrical target in the TomoTherapy treatment planning system (TPS) version 3.2.1. Intentional misalignments of 5 mm …

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Application Of Peer Instruction In The High School Setting, Wiley Iverstine Jan 2010

Application Of Peer Instruction In The High School Setting, Wiley Iverstine

LSU Master's Theses

This study investigates whether the response component of Peer Instruction can be successfully added to my normal classroom instruction creating higher gains in student conceptual understanding of force concepts. This action research is intended to analyze this goal for possible application in any regular high school Physics classroom, using myself as a case study. The Force Concept Inventory was used as a pretest/posttest determinate of the learning gains of 85 students spread through four regular Physics classes during the 2009-10 school year. Forty-Two of these students were used as an experimental group where the response component of Peer Instruction was …

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Using Inoceramid Bivalve Taphonomy As A Paleoenvironmental Indicator Across The Cenomanian/Turonian Horizon At The Pueblo, Colorado Gssp, Jacob Frederick Grosskopf Jan 2010

Using Inoceramid Bivalve Taphonomy As A Paleoenvironmental Indicator Across The Cenomanian/Turonian Horizon At The Pueblo, Colorado Gssp, Jacob Frederick Grosskopf

LSU Master's Theses

Recent paleoenvironmental and geochemical studies indicate that benthic conditions during Oceanic Anoxic Event II (OAE II) (93.5 Mya) in the Cretaceous Interior Seaway (CIS) were dysoxic rather than anoxic. In this thesis, dysoxic benthic conditions were tested for by observing patterns in taphonomic alteration of the calcite portions of inoceramid bivalve shells during and after OAE II. Inoceramid valves were extracted from beds that spanned OAE II at the Cenomanian/Turonian Global Boundary Stratotype Section and Point (GSSP) in Pueblo, Colorado: beds 62 (Hartland Shale), 72 (Bridge Creek Limestone), and 115 (Bridge Creek Limestone). Degree of alteration was tallied using categorical …

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Delineation Of A Produced Water Plume In Pointe Coupee Parish, Louisiana, Matthew C. Smith Jan 2010

Delineation Of A Produced Water Plume In Pointe Coupee Parish, Louisiana, Matthew C. Smith

LSU Master's Theses

Three pits were excavated in the 1960’s at the Fordoche Oil Field in Lottie, Louisiana, as evaporation pits for oil well produced brines. The pits were closed and completed in the 1980’s. Previous studies indicate that produced water has leached into the subsurface within the area to the south and southeast of the pits. Ground penetrating radar (GPR) was utilized in an attempt to delineate the present location of the plume as well as test the feasibility of GPR within a clayey soil in south Louisiana. In addition to collection of GPR data, electrical conductivity logs and soil cores (including …

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Investigating The Ironwood Tree (Casuarina Equisetifolia) Decline On Guam Using Applied Multinomial Modeling, Karl Anthony Schlub Jan 2010

Investigating The Ironwood Tree (Casuarina Equisetifolia) Decline On Guam Using Applied Multinomial Modeling, Karl Anthony Schlub

LSU Master's Theses

The ironwood tree (Casuarina equisetifolia), a protector of coastlines of the sub-tropical and tropical Western Pacific, is in decline on the island of Guam where aggressive data collection and efforts to mitigate the problem are underway. For each sampled tree the level of decline was measured on an ordinal scale consisting of five categories ranging from healthy to near dead. Several predictors were also measured including tree diameter, fire damage, typhoon damage, presence or absence of termites, presence or absence of basidiocarps, and various geographical or cultural factors. The five decline response levels can be viewed as categories of a …

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A Petrophysical Evaluation Of Factors That Control Cap Rock Seal Quality, Andrew Tyler Harrison Jan 2010

A Petrophysical Evaluation Of Factors That Control Cap Rock Seal Quality, Andrew Tyler Harrison

LSU Master's Theses

Textural and mineralogical variations within 33 shale samples were analyzed to provide a model for predication of hydrocarbon top-seal efficiency. Variation in mineral abundances in the subsurface influences petrophysical properties and other characteristics of hydrocarbon sealing sequences and reservoirs. In geophysical well logs, various proxies, such as gamma ray emission and neutron absorption, are used to assess changes in mineral composition. This study directly compares X-ray diffraction measurements of mineral percentages and geophysical responses from Middle Miocene cored intervals in the Santa Cruz Well; Mississippi Canyon block 519, Gulf of Mexico with those derived from well logging. Distinct textural differences …

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Patterns Of Habitat Suitability And Abundance Trends Of Current And Candidate Coastal Fish Species Of Concern In Louisiana, Elin Rose Sandy Jan 2010

Patterns Of Habitat Suitability And Abundance Trends Of Current And Candidate Coastal Fish Species Of Concern In Louisiana, Elin Rose Sandy

LSU Master's Theses

Louisiana’s estuaries and coastal waters play an important role in providing habitat for several estuarine-dependent species and also serve as a nursery for the juveniles of several other species. The current rate of land loss in Louisiana and the decline of estuarine-dependent species force us to improve our understanding of the recruitment of these species into Louisiana’s estuaries. Habitat suitabilities were developed for several fish species of concern (SOC) and other estuarine-dependent species across three environmental gradients, abundance patterns were developed for seasons, five-year intervals, and coastal study areas (CSAs). Chi-square analyses and ANOVAs were then used to test for …

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Misconceptions On Force And Gravity Among High School Students, Jane Ragasa Pablico Jan 2010

Misconceptions On Force And Gravity Among High School Students, Jane Ragasa Pablico

LSU Master's Theses

The goal of this study is to determine prevalent or dominant misconceptions on force and gravity among high school students. A survey instrument consisting of 12 qualitative questions requiring both answers and written explanations was used to gather students’ ideas and beliefs in situations involving force and gravity. Furthermore, it examined whether the proportion of students having misconceptions per question are correlated with gender and the type of school Physics background. The results show that the respondents have misconceptions that are similar to the misconceptions found in previous research. The number of misconceptions and the proportion of students having misconceptions …

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Influences On Public Support For Green Infrastructure: An Examination Of Urban Wetland Restoration In Post-Katrina New Orleans, Lynette C. Overholser Jan 2010

Influences On Public Support For Green Infrastructure: An Examination Of Urban Wetland Restoration In Post-Katrina New Orleans, Lynette C. Overholser

LSU Master's Theses

The research examines patterns of likely support for urban wetland restoration in the Greater New Orleans area. Through multi-variate statistical analysis of responses derived from an original survey of homeowners in New Orleans, key factors are identified that explain variation in residents’ willingness to accept such areas and their perceptions of ecological benefits associated with a theoretical wetlands restoration design for the Gentilly area. Further, the analysis determines the extent to which direct experience with Hurricane Katrina may influence public support for this and other green infrastructure projects. The results of the data collected show that many people in New …

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New Strategies For Phase Estimation In Quantum Optics, Yang Gao Jan 2010

New Strategies For Phase Estimation In Quantum Optics, Yang Gao

LSU Doctoral Dissertations

One important problem in quantum optics is to resolve an extremely small change of phase shift. The complementarity between photon number and phase sets an ultimate limit, the so-called Heisenberg limit, on the phase measurement sensitivity. The precise phase estimation has many technological applications, such as optical gyroscopes, gravitational wave detection, quantum imaging and sensing. In this thesis I show that the utilization of the parity measurement in the optical interferometry is actually applicable to a wide range of quantum entangled input states. Comparison of the performance of the various quantum states then can be made within such a unified …

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Robotics As A Means Of Increasing Student Achievement In Middle School Science, Ingrid Lorelei Jomento-Cruz Jan 2010

Robotics As A Means Of Increasing Student Achievement In Middle School Science, Ingrid Lorelei Jomento-Cruz

LSU Master's Theses

This study reports on the effectiveness of a Robotics engineering curriculum in increasing the middle school students‘ achievement in science and math. Specifically, it aimed to find out if the students taking the robotics class performed significantly higher in science and math than a control group. The research examined and compared the scores in a pre and posttest and the normalized learning gains of students taking robotics in addition to their regular science and math versus those who are taking science and math only. Although this study showed that there is no significant difference in the science achievement scores of …

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Taphonomy And Sedimentology Of Two Miocene Vertebrate Fossil Sites On Fort Polk, Louisiana, Julie Lynn Hill Jan 2010

Taphonomy And Sedimentology Of Two Miocene Vertebrate Fossil Sites On Fort Polk, Louisiana, Julie Lynn Hill

LSU Master's Theses

The discovery of a terrestrial mammalian fauna in the Miocene deposits on Fort Polk, Louisiana, fills a geographic gap in the Gulf Coast paleontological framework, but the provenance of the fossils, nature of the depositional environments, and relationships between the sites is still debated. This is especially true for the TVOR site cluster. TVOR SE has a mixture of marine and terrestrial vertebrates in association with a partly dissolved, in situ bed of articulated oyster shells, which stands in contrast to the fully terrestrial and freshwater assemblage at TVOR, and the indeterminate site TVOR S. Although limited outcrop may bias …

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The Impact Of Hurricanes Katrina And Rita On The Louisiana Judicial System, Charles Simon Mccowan, Iii Jan 2010

The Impact Of Hurricanes Katrina And Rita On The Louisiana Judicial System, Charles Simon Mccowan, Iii

LSU Master's Theses

This thesis is a case study of the impact of Hurricanes Katrina and Rita on the Louisiana court system and the response of the court system to the aftermath of these two hurricanes. Although this thesis focuses on one state’s court system’s response to two natural disasters, the research, conclusions and recommendations are transferable to other states. Hurricanes Katrina and Rita struck the Gulf Coast in 2005 devastating large areas in Louisiana, Texas, Mississippi and Alabama. Millions of people, including judges and attorneys, were forced to evacuate their homes, courts and law offices. The Hurricanes caused interruptions to both federal …

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Multi-Scale Habitat Associations Of Shorebirds During Spring Migration In Southwestern Louisiana Rice Fields, Rachel K. Villani Jan 2010

Multi-Scale Habitat Associations Of Shorebirds During Spring Migration In Southwestern Louisiana Rice Fields, Rachel K. Villani

LSU Master's Theses

Rice is the most common wetland crop in the world, and important for waterbirds and shorebirds worldwide, including the United States. In Louisiana, shorebirds use rice fields during spring migration, and are an important for foraging and refueling during migration. However, competing land uses and restoration projects may reduce the availability of rice fields, and impact the landscape that shorebirds use during migration. To determine how shorebirds use the landscape, I evaluated local and landscape factors affecting shorebird use of rice fields during spring migration in southwestern Louisiana. Using five habitat suitability zones (HSZs) based on rice density and canopy …

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Status Of Wintering Grassland Birds In A Post-Hurricane, Salvage-Logged Forest, Matthew Edward Brooks Jan 2010

Status Of Wintering Grassland Birds In A Post-Hurricane, Salvage-Logged Forest, Matthew Edward Brooks

LSU Master's Theses

North American grassland birds have been declining at an alarming rate. Winter habitat for grassland species in the southeastern U.S. generally occurs within forests subject to management. I studied wintering grassland bird communities in De Soto National Forest in southern Mississippi. My objectives were to: 1) Assess bird communities and vegetation structure in upland forest stands that were salvage-logged following Hurricane Katrina, in stands managed for Red-cockaded Woodpeckers (Picoides borealis, RCW), and in stands containing bogs; and 2) Determine the extent of the association between vegetation and occurrence of the common wintering grassland birds. I conducted bird and vegetation surveys …

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Evaluation Of The Effectiveness Of Cooperative Learning Structures In Improving Students' Performance, Jonah Njenga Jan 2010

Evaluation Of The Effectiveness Of Cooperative Learning Structures In Improving Students' Performance, Jonah Njenga

LSU Master's Theses

In a desperate attempt to improve high school classroom performances, recently, schools have begun to move towards incorporating cooperative learning strategies into their classrooms. Generally, cooperative learning strategies can be described as the use of small groups to encourage learners work together and accomplish shared goals and subsequently maximize theirs and others’ potential. In an attempt to evaluate the effectiveness of this strategy on classroom learning, this study compares the gains in means of scores between a group taught using cooperative learning strategies and another group taught using non-cooperative learning strategies. Fifty-three students taking Algebra I were given a pretest …

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Estuarine Phytoplankton Response To Annual And Manipulated River Inputs, Jessica Czubakowski Jan 2010

Estuarine Phytoplankton Response To Annual And Manipulated River Inputs, Jessica Czubakowski

LSU Master's Theses

River water entering estuaries affects the physical and chemical environment at irregular intervals creating a highly dynamic aquatic habitat. Phytoplankton are important primary producers in estuaries that respond quickly to their changing environment. Since 1991, Breton Sound estuary in southeast Louisiana has been directly influenced by Mississippi River water through the Caernarvon Freshwater Diversion structure. Over a 12 month period, the phytoplankton response was examined, in terms of biomass, abundance, community composition and potential phycotoxin production to seasonal changes in river input into the estuary. Within this 12 month period, a short pulse study was also carried out to examine …

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Prototype Electron Phantom For Radiographic And Radiochromic Film Dosimetry, Chad Joseph Robertson Jan 2010

Prototype Electron Phantom For Radiographic And Radiochromic Film Dosimetry, Chad Joseph Robertson

LSU Master's Theses

Robertson, Chad Joseph, B.S. Louisiana Tech University, 2006 Master of Science, Spring Commencement, 2006 Major: Medical Physics and Health Physics Prototype Electron Phantom for Radiographic and Radiochromic Film Dosimetry Thesis directed by Professor Kenneth R. Hogstrom Pages in thesis, 133. Words in abstract, 350 ABSTRACT Purpose: The purpose of this work is to develop a solid electron beam film phantom for use with radiographic film (RGF) and radiochromic film (RCF) to measure relative dose distributions in a principal plane containing the central axis for 6¨C20MeV electron beams. It was hypothesized that relative dose distributions measured using film will agree with …

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Spatial Variations Of Salinity, Temperature And Pressure On The Flank Of A Salt Dome, Offshore Louisiana: Implications For Mechanisms Of Fluid Flow, Andrew Kevin Steen Jan 2010

Spatial Variations Of Salinity, Temperature And Pressure On The Flank Of A Salt Dome, Offshore Louisiana: Implications For Mechanisms Of Fluid Flow, Andrew Kevin Steen

LSU Master's Theses

Salt dome dissolution in the Gulf of Mexico sedimentary basin is a primary cause for elevated pore water salinities in the subsurface. Temperature, pressure, salinity, lithology and fluid density are parameters often used to identify preferential conduits and driving forces for fluid migration. These parameters were calculated using 20 wireline logs covering 40 km² on the south flank of a salt dome on the continental shelf, offshore Louisiana. 3-D seismic has been utilized to determine location of faults, to aid in sand correlation, and to provide a structural overview of the dome. Vertical and lateral variations in lithology, salinity, temperature, …

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