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Articles 1 - 30 of 2278

Full-Text Articles in Physical Sciences and Mathematics

The Effects Of Pressure And Magnetic Field On Phase Transitions And Related Physical Properties In Solid State Caloric Materials, Ahmad Ikhwan Us Saleheen Nov 2018

The Effects Of Pressure And Magnetic Field On Phase Transitions And Related Physical Properties In Solid State Caloric Materials, Ahmad Ikhwan Us Saleheen

LSU Doctoral Dissertations

Solid-state caloric effects, such as the magnetocaloric (MCE) and barocaloric (BCE) effects, may be utilized in future cooling technologies that are more efficient and environment-friendly. Large caloric effects often occur near phase transitions, especially near coupled first-order magnetostructural transitions (MST), and are initiated by external parameters, such as magnetic field or hydrostatic pressure. In this dissertation, the effects of pressure, temperature, and magnetic field on the phase transitions in three material systems are studied in order to elucidate how the respective caloric effects are affected.

In the first study, the realization of a coupled MST in a MnNiSi-based system through ...


Longitudinal Study Of The Attitudes And Behaviors Of Environmental Education Program Participants., Kasie R. Dugas Oct 2018

Longitudinal Study Of The Attitudes And Behaviors Of Environmental Education Program Participants., Kasie R. Dugas

LSU Master's Theses

The goal of this longitudinal study was to measure the attitudes and behaviors of participants of the Marsh Maneuvers program over the course of the last 25 years. The goal of the Marsh Maneuvers program is to educate students into becoming environmentally literate adults. Environmental literacy is considered herein to be people possessing knowledge about and positive attitudes and behaviors towards the environment. Although students learn basic science and environmental knowledge in the classroom, true environmental literacy is believed to require more hands-on understanding of the material. To evaluate the effectiveness of the program, the following three objectives were completed ...


Beam Theory For Classical And Quantum Nonlinear Optics---Exposing Classical And Quantum Correlations Of Transverse-Spatial Modes, Robert Nicholas Lanning Oct 2018

Beam Theory For Classical And Quantum Nonlinear Optics---Exposing Classical And Quantum Correlations Of Transverse-Spatial Modes, Robert Nicholas Lanning

LSU Doctoral Dissertations

Optics is arguably the most important branch of physics that has ever been studied. It is not only an essential ingredient of many other branches of physics that we study, it governs how we see, how we measure, and how we communicate in the modern world. And as the world continues to change, so do our tools and resources. In a relatively short amount of time, we have progressed from rudimentary tools that shape the world around us, to tools that harness the fundamental laws of nature. Unsurprisingly, the laws of nature governing optics remain paramount. This is because many ...


Effective Visualization Approaches For Ultra-High Dimensional Datasets, Gurminder Kaur Oct 2018

Effective Visualization Approaches For Ultra-High Dimensional Datasets, Gurminder Kaur

LSU Doctoral Dissertations

Multivariate informational data, which are abstract as well as complex, are becoming increasingly common in many areas such as scientific, medical, social, business, and so on. Displaying and analyzing large amounts of multivariate data with more than three variables of different types is quite challenging. Visualization of such multivariate data suffers from a high degree of clutter when the numbers of dimensions/variables and data observations become too large. We propose multiple approaches to effectively visualize large datasets of ultrahigh number of dimensions by generalizing two standard multivariate visualization methods, namely star plot and parallel coordinates plot. We refine three ...


Observation Of High-Energy Gamma-Rays With The Calorimetric Electron Telescope (Calet) On-Board The International Space Station, Nicholas Wade Cannady Oct 2018

Observation Of High-Energy Gamma-Rays With The Calorimetric Electron Telescope (Calet) On-Board The International Space Station, Nicholas Wade Cannady

LSU Doctoral Dissertations

The CALorimetric Electron Telescope (CALET) is a multi-instrument high-energy astrophysics observatory deployed to the International Space Station (ISS) in August 2015. The primary instrument is the calorimeter (CAL), which is intended for measurement of the cosmic ray electron flux in the energy range 10 GeV - 20 TeV. The CAL is also sensitive to gamma-rays in the energy range 1 GeV - 10 TeV and protons and nuclei up to PeV energies. Also present on the CALET payload are an Advanced Stellar Compass (ASC) for the fine determination of the pointing direction and the CALET Gamma-ray Burst Monitor (CGBM) for the observation ...


Theoretical Studies Of Ultrafast Electron Dynamics In Atoms And Molecules Via High-Order Harmonic Generation, Paul Vincent Abanador Oct 2018

Theoretical Studies Of Ultrafast Electron Dynamics In Atoms And Molecules Via High-Order Harmonic Generation, Paul Vincent Abanador

LSU Doctoral Dissertations

The interaction of atoms and molecules with strong laser pulses is of fundamental interest in physics and chemistry. Notably, the process known as high-order harmonic generation (HHG) refers to the production of extreme-ultraviolet (XUV) light, which occurs when an ensemble of atoms or molecules is subjected to a strong infrared laser field. Characterized by an attosecond time scale (1 as = 10-18 s), the HHG process provides the capability for experimental measurements to capture the ultrafast motion of electrons in these target atoms and molecules. The underlying physical mechanism behind this process naturally leaves imprints in the properties of the ...


Bipartite Quantum Interactions: Entangling And Information Processing Abilities, Siddhartha Das Oct 2018

Bipartite Quantum Interactions: Entangling And Information Processing Abilities, Siddhartha Das

LSU Doctoral Dissertations

The aim of this thesis is to advance the theory behind quantum information processing tasks, by deriving fundamental limits on bipartite quantum interactions and dynamics. A bipartite quantum interaction corresponds to an underlying Hamiltonian that governs the physical transformation of a two-body open quantum system. Under such an interaction, the physical transformation of a bipartite quantum system is considered in the presence of a bath, which may be inaccessible to an observer. The goal is to determine entangling abilities of such arbitrary bipartite quantum interactions. Doing so provides fundamental limitations on information processing tasks, including entanglement distillation and secret key ...


Nonlocal Diffusions And The Quantum Black-Scholes Equation: Modelling The Market Fear Factor, Will Hicks Oct 2018

Nonlocal Diffusions And The Quantum Black-Scholes Equation: Modelling The Market Fear Factor, Will Hicks

Communications on Stochastic Analysis

No abstract provided.


Parametric Family Of Sdes Driven By Lévy Noise, Suprio Bhar, Barun Sarkar Oct 2018

Parametric Family Of Sdes Driven By Lévy Noise, Suprio Bhar, Barun Sarkar

Communications on Stochastic Analysis

No abstract provided.


A Decomposition Of A Space Of Multiple Wiener Integrals By The Difference Of Two Independent Lévy Processes In Terms Of The Lévy Laplacian, Atsushi Ishikawa Oct 2018

A Decomposition Of A Space Of Multiple Wiener Integrals By The Difference Of Two Independent Lévy Processes In Terms Of The Lévy Laplacian, Atsushi Ishikawa

Communications on Stochastic Analysis

No abstract provided.


A Stochastic Integral By A Near-Martingale, Shinya Hibino, Hui-Hsiung Kuo, Kimiaki Saitô Oct 2018

A Stochastic Integral By A Near-Martingale, Shinya Hibino, Hui-Hsiung Kuo, Kimiaki Saitô

Communications on Stochastic Analysis

No abstract provided.


Reversibility Checking For Markov Chains, P. H. Brill, Chi Ho Cheung, Myron Hlynka, Q. Jiang Oct 2018

Reversibility Checking For Markov Chains, P. H. Brill, Chi Ho Cheung, Myron Hlynka, Q. Jiang

Communications on Stochastic Analysis

No abstract provided.


Directional Malliavin Derivatives: A Characterisation Of Independence And A Generalised Chain Rule, Stefan Koch Oct 2018

Directional Malliavin Derivatives: A Characterisation Of Independence And A Generalised Chain Rule, Stefan Koch

Communications on Stochastic Analysis

No abstract provided.


An Asymptotic Comparison Of Two Time-Homogeneous Pam Models, Hyun-Jung Kim, Sergey Vladimir Lototsky Oct 2018

An Asymptotic Comparison Of Two Time-Homogeneous Pam Models, Hyun-Jung Kim, Sergey Vladimir Lototsky

Communications on Stochastic Analysis

No abstract provided.


Impacts Of Updated Design Rainfall Values On Louisiana Infrastructure, Mario Durbic Sep 2018

Impacts Of Updated Design Rainfall Values On Louisiana Infrastructure, Mario Durbic

LSU Master's Theses

The Louisiana Department of Transportation and Development (LADOTD) has a Hydraulics Manual which sets forth drainage design standards and codes for projects. The Manual contains maximum annual 24-hour rainfall maps and Intensity-Duration-Frequency (IDF) curves for the return periods of 2, 5, 10, 25, 50, and 100 years. The Manual divides Louisiana into three regions and specifies that all of the cities within a given region should use the same estimated rainfall intensities and rainfall depths. NOAA Atlas 14, the Precipitation-Frequency Atlas of United States, contains the latest rainfall data and statistics for much of the United States and provides the ...


High-Dimensional Isotope Relationships, Yuyang He Aug 2018

High-Dimensional Isotope Relationships, Yuyang He

LSU Doctoral Dissertations

High-dimensional isotope relationships describes the relationships of two or more element or position-specific (PS) elements in the same molecule or ion. It provides us more powerful tools to study reaction mechanisms and dynamics. Chapter 1 is about dual or multiple stable isotope relationship on δ-δ (or δ'-δ') space. While temporal data sampled from a closed-system can be treated by a Rayleigh Distillation Model (RDM), spatial data should be treated by a Reaction-Transport Model (RTM). Here we compare the results of a closed-system RDM to a RTM for systems with diffusional mass transfer by simulating the trajectories on nitrate's ...


Using Local Fishery Monitoring To Understand Small-Scale Coastal Fisheries In Tanzania, Matthew Robertson Aug 2018

Using Local Fishery Monitoring To Understand Small-Scale Coastal Fisheries In Tanzania, Matthew Robertson

LSU Master's Theses

Nearshore marine fisheries provide the main source of protein for nearly 9 million people in the coastal villages of Tanzania, yet for decades the fisheries have shown signs of overexploitation. These fisheries are small-scale and co-managed by local coastal communities in groups known as Beach Management Units (BMUs). BMUs monitor individual fishing trip data (e.g. gear, vessel, taxa); however, these data have only been analyzed in nationally aggregated statistics and to our knowledge, are not presently used in management decision making. The present thesis aimed to identify the forms of data and information that local fishery monitoring can record ...


Verification And Evaluation Of A Passive Intensity Modulation Device For Bolus Electron Conformal Therapy, Elizabeth Noel Hilliard Aug 2018

Verification And Evaluation Of A Passive Intensity Modulation Device For Bolus Electron Conformal Therapy, Elizabeth Noel Hilliard

LSU Master's Theses

Purpose: Bolus electron conformal therapy (BECT) provides effective radiation treatment for superficial cancers and other diseases close to the skin surface, but can have as great as a 30% planning target volume (PTV) dose heterogeneity due to scattering from the irregular proximal bolus surface. Intensity modulated (IM) BECT can improve PTV dose homogeneity, but is not currently available. This study fabricated patient-specific passive intensity modulators and validated their delivering planned dose distributions calculated by a modified pencil beam redefinition algorithm (PBRA).

Methods: Two test-patterns and four patient-specific intensity modulators were designed, fabricated, and tested. Dose plans were generated using a ...


Exit-Time Of Granular Media Equation Starting In A Local Minimum, Julian Tugaut Aug 2018

Exit-Time Of Granular Media Equation Starting In A Local Minimum, Julian Tugaut

Communications on Stochastic Analysis

No abstract provided.


Bsdes On Finite And Infinite Horizon With Time-Delayed Generators, Peng Luo, Ludovic Tangpi Aug 2018

Bsdes On Finite And Infinite Horizon With Time-Delayed Generators, Peng Luo, Ludovic Tangpi

Communications on Stochastic Analysis

No abstract provided.


Arratia Flow With Drift And Trotter Formula For Brownian Web, Andrey A. Dorogovtsev, M. B. Vovchanskii Aug 2018

Arratia Flow With Drift And Trotter Formula For Brownian Web, Andrey A. Dorogovtsev, M. B. Vovchanskii

Communications on Stochastic Analysis

No abstract provided.


Stochastic Representation Of Tau Functions With An Application To The Korteweg-De Vries Equation, Michèle Thieullen, Alexis Vigot Aug 2018

Stochastic Representation Of Tau Functions With An Application To The Korteweg-De Vries Equation, Michèle Thieullen, Alexis Vigot

Communications on Stochastic Analysis

No abstract provided.


A Discrete Time Approximations For Certain Class Of One-Dimensional Backward Stochastic Differential Equations Via Girsanov's Theorem, Aissa Sghir, Driss Seghir, Soukaina Hadiri Aug 2018

A Discrete Time Approximations For Certain Class Of One-Dimensional Backward Stochastic Differential Equations Via Girsanov's Theorem, Aissa Sghir, Driss Seghir, Soukaina Hadiri

Communications on Stochastic Analysis

No abstract provided.


Symmetric Weighted Odd-Power Variations Of Fractional Brownian Motion And Applications, David Nualart, Raghid Zeineddine Aug 2018

Symmetric Weighted Odd-Power Variations Of Fractional Brownian Motion And Applications, David Nualart, Raghid Zeineddine

Communications on Stochastic Analysis

No abstract provided.


A Triple Comparison Between Anticipating Stochastic Integrals In Financial Modeling, Joan Bastons, Carlos Escudero Aug 2018

A Triple Comparison Between Anticipating Stochastic Integrals In Financial Modeling, Joan Bastons, Carlos Escudero

Communications on Stochastic Analysis

No abstract provided.


Ultrafast And Nonlinear Spectroscopy Of Nanomaterials, Rami Anthony Khoury Jul 2018

Ultrafast And Nonlinear Spectroscopy Of Nanomaterials, Rami Anthony Khoury

LSU Doctoral Dissertations

Ultrafast and nonlinear spectroscopies are implemented in the investigation of excited-state dynamics and structural properties of materials and nanomaterials. In the first study, the excited-state dynamics of size-dependent colloidal TiO2-Au nanocomposites are investigated using ultrafast transient absorption spectroscopy. The dynamics corresponding to the plasmon depletion band are characterized by electron-phonon and phonon-phonon coupling lifetimes that are observed to be independent of the gold nanocluster shell thickness. The excited-state dynamics corresponding to the interband transition of gold is also spectrally overlapped with the interfacial electron transfer lifetime, which is shown to decrease as the nanocluster shell thickness increases. In ...


Investigation Of Stereotactic Body Radiation Therapy Delivery Accuracy On An Elekta Linear Accelerator, Addie Barron Jul 2018

Investigation Of Stereotactic Body Radiation Therapy Delivery Accuracy On An Elekta Linear Accelerator, Addie Barron

LSU Master's Theses

Purpose: This work investigated the delivery accuracy of high-dose lung and spine stereotactic treatments delivered with the Elekta Infinity and Versa HD platforms. The accuracy of these platforms will be used for consideration in implementing a spine stereotactic radiosurgery (SSRS) program at Mary Bird Perkins Cancer Center.

Methods: A geometric phantom was used to perform Winston-Lutz type tests that assessed the relevant degrees of freedom (gantry, collimator, and couch) of the delivery system. A lung stereotactic body radiation therapy (SBRT) and spine SRS treatment plan were generated for use in end-to-end testing. Delivery accuracy was tested using a novel diode ...


Perils Of The Fungal Kingdom: Mycotoxins In Food And Feed, Adrianna Isobel Pribil Jul 2018

Perils Of The Fungal Kingdom: Mycotoxins In Food And Feed, Adrianna Isobel Pribil

LSU Master's Theses

Humans and fungi have a complex relationship, especially in regards to the many fungal secondary metabolites that can be produced. When secondary metabolites are toxic to animals and humans they are defined as mycotoxins. Fungi can grow on crops pre-harvest and post-harvest, and have the potential to produce mycotoxins which occur regularly in animal feed and food for human consumption. In high doses, mycotoxins cause variety of problems that result in economic losses and extreme health issues. However, multiple mycotoxins will co-occur in nature and commonly occur in low doses. Thus chronic low daily doses of multiple mycotoxins overtime may ...


Curve Tracking Control Under State Constraints And Uncertainties, Robert Kelly Sizemore Jul 2018

Curve Tracking Control Under State Constraints And Uncertainties, Robert Kelly Sizemore

LSU Doctoral Dissertations

We study a class of steering control problems for free-moving particles tracking a curve in the plane and also in a three-dimensional environment, which are central problems in robotics. In the two-dimensional case, we provide adaptive controllers for curve tracking under unknown curvatures and control uncertainty. The system dynamics include a nonlinear dependence on the curvature, and are coupled with an estimator for the unknown curvature to form the augmented error dynamics. This nonlinear dependence puts our curvature identification objective outside the scope of existing adaptive tracking and parameter identification results that were limited to cases where the unknown parameters ...


Groundwater And Thermal Legacy Of A Large Paleolake In Taylor Valley, East Antarctica As Evidenced By Airborne Electromagnetic And Sedimentological Techniques, Krista Falcon Myers Jul 2018

Groundwater And Thermal Legacy Of A Large Paleolake In Taylor Valley, East Antarctica As Evidenced By Airborne Electromagnetic And Sedimentological Techniques, Krista Falcon Myers

LSU Master's Theses

During the Last Glacial Maximum, grounded ice in the Ross Sea extended into the otherwise ice-free McMurdo Dry Valleys, creating a series of large ice dammed paleolakes. Grounded ice within the mouth of Taylor Valley allowed for lake levels to reach elevations not possible at modern day and formed what is known as Glacial Lake Washburn (GLW). GLW extended from the eastern portion of Taylor Valley roughly 20 km west to a level ~300 m higher than modern day Lake Fryxell. The formation and existence of GLW has been debated, though previous studies correlate the timing of GLW with early ...