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Physics

University of Louisville

Theses/Dissertations

2021

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Towards Long Term Colloid Suspension In A Vertically Rotated System., Md Mahmudur Rahman Dec 2021

Towards Long Term Colloid Suspension In A Vertically Rotated System., Md Mahmudur Rahman

Electronic Theses and Dissertations

Within a colloidal suspension gravity may compromise the observation of governing physical interactions, especially those that are weak and/or take significant time to develop. Conducting the experiment in a long-term microgravity environment is a viable option to negate gravitational effects, though significant resources are required to do so. While it may not be possible to simulate long-term microgravity terrestrially, particles can resist quick sedimentation in a confined suspension system rotating vertically with appropriate rotation speed. The goal of the investigation is to demonstrate the existence of long-term particle suspension regime for a certain colloidal suspension while characterizing colloidal behavior due …

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Ultrafast Magnetic Entropy Dynamics With Time-Resolved Pump-Probe Magneto-Optical Technique., Sahar Goharshenasanesfahani Dec 2021

Ultrafast Magnetic Entropy Dynamics With Time-Resolved Pump-Probe Magneto-Optical Technique., Sahar Goharshenasanesfahani

Electronic Theses and Dissertations

It has been observed that ultrathin films, multilayers, or magnetic nanostructures indicate novel magnetic phenomena that differ profoundly from the respective bulk properties. Besides, because of the broad applications of these magnetic materials in the industry, they are an exciting research area. Hence, investigating the low-dimensional magnetic systems is one of the most active fields in experimental condensed matter physics. Magnetization dynamics can occur over a wide range of time scales (from seconds to femtoseconds). Some of these processes even occur on time scales as short as a few picoseconds (10-12s) or femtoseconds (10-15s). Measurement of …

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First Principle Studies Of The Effects Of Alkali-Metal Intercalation On Structural Transition From Black To Blue Phosphorene And The Adsorption Of N2h4 On Ws2 Layers., Md Rajib Khan Musa Dec 2021

First Principle Studies Of The Effects Of Alkali-Metal Intercalation On Structural Transition From Black To Blue Phosphorene And The Adsorption Of N2h4 On Ws2 Layers., Md Rajib Khan Musa

Electronic Theses and Dissertations

A comprehensive density functional theory calculation has been conducted to seek a potential structural transition from black to blue phosphorene layers, with a focus on the roles played by alkali-metal intercalation in black phosphorene/phosphorus. This study reveals that at sufficiently high Li concentration and specific, well-defined configurations, a phase transition from black to blue phosphorene can take place. The Li atoms intercalated in black phosphorene could act as a “catalyst” in the“reactive region” of the lone pair of P atoms, leading to a P-P bond breaking and, subsequently, a local structural transformation from an orthorhombic lattice to an assembly of …

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Structural, Vibrational And Transport Properties Of Novel Complex Systems., Bhupendra Man Shing Karki Aug 2021

Structural, Vibrational And Transport Properties Of Novel Complex Systems., Bhupendra Man Shing Karki

Electronic Theses and Dissertations

Electron correlation effects in quantum materials are very strong. It is critical to investigate the structure of quantum materials to better understand and manipulate their physical properties. Quantum effects are prominent at the atomic microscopic length scale, which can not be examined by average long range structural measurements using traditional diffraction methods. Instead, pair distribution function (PDF) analysis, a local structure probe, can effectively unveil the mystery of local structure, which is more sensitive to local behavior than bulk average features. The first section of my dissertation will concentrate on the local structural study of the Iron oxy-chalcogenides, {\cSSe}, which …

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Intercalation And High Pressure Studies Of Black Phosphorous - Pathways To Novel Materials And Physics., Manthila Chathurange Rajapakse Aug 2021

Intercalation And High Pressure Studies Of Black Phosphorous - Pathways To Novel Materials And Physics., Manthila Chathurange Rajapakse

Electronic Theses and Dissertations

Discovery of graphene in 2004 initiated a new trend of materials known as two-dimensional (2D) materials which have exciting surface properties and anisotropies than their bulk counterparts. Phosphorene, which is the layered version of black phosphorous (BP) is one of the top 2D materials in terms of research interests and applications of the present day. Moving a step further, our interest is to understand the possibilities for structural modifications of phosphorene, by means of stimuli such as intercalation and high-pressure. It has been predicted by theoretical studies that these stimuli may lead to the formation of new structures and phases …

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Software Validation And Data Quality Monitoring Of The Klm Detector At Belle Ii., Dustyn Hofer May 2021

Software Validation And Data Quality Monitoring Of The Klm Detector At Belle Ii., Dustyn Hofer

College of Arts & Sciences Senior Honors Theses

The Belle II Experiment at the SuperKEKB collider in Tsukuba, Japan is the latest of a new generation of B-factory experiments, designed to produce B meson particles in abundance. The aim of the Belle II experiment is to "discover new physics in the decay of the bottom quark (b), charm quark (c) and tau lepton (τ) and explore the dark sector." The SuperKEKB collider aims to produce instantaneous luminosities of upwards of 8 × 1035 cm−2 s−1, nearly an order of magnitude higher than previous B- factory experiments Belle and BABAR. Software packages, such as physics modules for the popular …

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Study Of Neutral Hadron Production In A High Intensity Particle Physics Experiment., Jake W. Berg May 2021

Study Of Neutral Hadron Production In A High Intensity Particle Physics Experiment., Jake W. Berg

Electronic Theses and Dissertations

In this dissertation I present independent measurements of the multiplicities, R, of π0 and η mesons produced in annihilation interactions of electrons and positrons at a center-of-mass energy of 10.54 GeV. Data were collected using the BaBar detector at the PEP-II storage rings located at the SLAC National Accelerator Laboratory in Menlo Park, California. Both mesons have a decay mode to two photons, which is used to identify them and measure their production per event. I find R(π0) = 2.8±0.3 per event and R(η) = 0.25±0.03 per event. I also present my contributions to …

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Ga-Based Iii-V Semiconductor Photoanodes For Solar Fuels And Novel Techniques To Investigate Their Photocorrosion., Sahar Pishgar May 2021

Ga-Based Iii-V Semiconductor Photoanodes For Solar Fuels And Novel Techniques To Investigate Their Photocorrosion., Sahar Pishgar

Electronic Theses and Dissertations

Solar energy is one of the most abundant renewable energy sources. However, the diurnal variation of the sun as well as seasonal and weather effects, limits the widespread global implementation of solar energy. Thus, Cost-effective energy storage is critical to overcome the intermittent nature of solar energy available on the earth. Photoelectrolysis of water to oxygen and hydrogen fuel is a promising large-scale solution to store intermittent solar energy in a dense and portable form. Photoelectrochemical (PEC) water-splitting, or artificial photosynthesis, research strives to develop a semiconductor photoelectrode with both high efficiency and long-term stability. Semiconductors of the III–V class …

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