Open Access. Powered by Scholars. Published by Universities.®

Physical Sciences and Mathematics Commons

Open Access. Powered by Scholars. Published by Universities.®

Physics

Institution
Keyword
Publication Year
Publication
Publication Type
File Type

Articles 1 - 30 of 32046

Full-Text Articles in Physical Sciences and Mathematics

Shadows Of A Schwarzschild Black Hole Surrounded By A Spherically Symmetric Dark Matter, Ahmad Ibrahim Jun 2022

Shadows Of A Schwarzschild Black Hole Surrounded By A Spherically Symmetric Dark Matter, Ahmad Ibrahim

Theses and Dissertations

In this thesis, using general relativity, the null geodesics and black hole shadow of a spherically symmetric configuration of a black hole (surrounded by a dark matter shell) are studied. First, the standard

results of the photon sphere of Schwarzschild de-Sitter black hole is revisited and analyzed more carefully. Secondly, using an ansatz (piecewise metric function) commonly used in the literature to describe the mass distribution of the spherically symmetric black hole - dark matter configuration, the null geodesics through vacuum and dark matter are analyzed. Assuming an observer located at a finite distance from the black hole outside the dark ...


Symmetries, Zero Modes And Light Transport In Non-Hermitian Photonics, Jose David Hernandez Rivero Jun 2022

Symmetries, Zero Modes And Light Transport In Non-Hermitian Photonics, Jose David Hernandez Rivero

Dissertations, Theses, and Capstone Projects

We approach some fundamental aspects of photonic dissipative systems treated by a non-Hermitian theory. Inspired by the possibilities provided by some major non-Hermitian symmetries, we study systematically the properties of the novel pseudochirality, pseudo-anti-Hermiticity, and supersymmetry. We analyze other aspect of photonics, the zero mode, which has a profound connection to non-Hermitian physics. We propose a scheme to realize a zero mode that exists even in the absence of symmetries. Finally, we approach light transport in non-Hermitian photonic systems, where the introduction of gain and loss can modify drastically the propagation speed of wavepackets.


Phase Transitions, Critical Phenomena, And Correlation Functions In The 2d Ising Model And Its Applications To Quantum Dynamics: A Tensor Network Approach, Sankhya Basu Jun 2022

Phase Transitions, Critical Phenomena, And Correlation Functions In The 2d Ising Model And Its Applications To Quantum Dynamics: A Tensor Network Approach, Sankhya Basu

Dissertations, Theses, and Capstone Projects

This thesis explores several aspects of the 2D Ising Model at both real and complex temperatures utilizing tensor network algorithms. We briefly discuss the importance of tensor networks in the context of forming efficient representations of wavefunctions and partition functions for quantum and classical many-body systems respectively, followed by a brief review of the tensor network renormalization algorithms to compute the one point and two point correlation functions. We use the Tensor Renormalization Group (TRG) to study critical phenomena and examine feasibility of accurate estimations of universal critical data for three critical points for three critical points in two dimensions ...


Optical Studies Of Wide Bandgap Photonic Materials, Nikesh Maharjan Jun 2022

Optical Studies Of Wide Bandgap Photonic Materials, Nikesh Maharjan

Dissertations, Theses, and Capstone Projects

In this dissertation work, optical properties of wide bandgap materials such as hexagonal Boron Nitride (h-BN) and Zinc Oxide (ZnO) have been studied. Deep UV photoluminescence spectroscopy was employed to study the optical properties of bulk h-BN and powder crystals using a laser of wavelength 200 nm, which is the fourth harmonic of Ti:Sapphire laser as excitation source. The properties and chemical compositions of annealed and unannealed bulk h-BN were investigated. The PL spectra from h-BN samples annealed at 900 ºC in ambient air, had strong phonon assisted band edge emissions along with a sharp atomic-like emission line at ...


In-Phantom Film Measurements Of Two Treatment Planning Systems For Single-Fraction Spine Sbrt, Michael J. Taylor May 2022

In-Phantom Film Measurements Of Two Treatment Planning Systems For Single-Fraction Spine Sbrt, Michael J. Taylor

LSU Master's Theses

Purpose: Treatment planning accuracy for spine stereotactic body radiation therapy (SBRT) varies depending on the dose calculation algorithm utilized in the treatment planning system (TPS). This project compared the end-to-end accuracy between spine SBRT plans calculated in a convolution-superposition based TPS (TPSCS) and Monte Carlo based TPS (TPSMC) with radiochromic film measurements. The hypothesis was that TPSMC would calculate the dose gradient in the critical region between the vertebral body and the spinal cord more accurately than TPSCS.

Methods: Single-fraction spine SBRT treatments following RTOG 0631 and local institutional guidelines were planned in TPSCS and ...


Implementation Of A Least Squares Method To A Navier-Stokes Solver, Jada P. Lytch, Taylor Boatwright, Ja'nya Breeden May 2022

Implementation Of A Least Squares Method To A Navier-Stokes Solver, Jada P. Lytch, Taylor Boatwright, Ja'nya Breeden

Rose-Hulman Undergraduate Mathematics Journal

The Navier-Stokes equations are used to model fluid flow. Examples include fluid structure interactions in the heart, climate and weather modeling, and flow simulations in computer gaming and entertainment. The equations date back to the 1800s, but research and development of numerical approximation algorithms continues to be an active area. To numerically solve the Navier-Stokes equations we implement a least squares finite element algorithm based on work by Roland Glowinski and colleagues. We use the deal.II academic library , the C++ language, and the Linux operating system to implement the solver. We investigate convergence rates and apply the least squares ...


Contributions Of Vibrational Spectroscopy To Virology: A Review, Iqra Chaudhary, Naomi Jackson, Denise Denning, Luke O'Neill, Hugh Byrne May 2022

Contributions Of Vibrational Spectroscopy To Virology: A Review, Iqra Chaudhary, Naomi Jackson, Denise Denning, Luke O'Neill, Hugh Byrne

Articles

Vibrational spectroscopic techniques, both infrared absorption and Raman scattering, are high precision, label free analytical techniques which have found applications in fields as diverse as analytical chemistry, pharmacology, forensics and archeometrics and, in recent times, have attracted increasing attention for biomedical applications. As analytical techniques, they have been applied to the characterisation of viruses as early as the 1970s, and, in the context of the coronavirus disease 2019 (COVID-19) pandemic, have been explored in response to the World Health Organisation as novel methodologies to aid in the global efforts to implement and improve rapid screening of viral infection. This review ...


Editorial Board May 2022

Editorial Board

Karbala International Journal of Modern Science

No abstract provided.


Simulating Photo-Disintegration Of 137cs Radioactive Waste Using Various Energies Of Gamma Photons, Hassanain H. Alkazzaz, Asia H. Al-Mashhadani, Kamal H. Lateef May 2022

Simulating Photo-Disintegration Of 137cs Radioactive Waste Using Various Energies Of Gamma Photons, Hassanain H. Alkazzaz, Asia H. Al-Mashhadani, Kamal H. Lateef

Karbala International Journal of Modern Science

In this study, the possibility of using gamma-ray in photo-disintegration method was examined so that it can be used in the remediation of 137Cs radionuclides waste materials by nuclear transmutation to convert long-lived nuclides to other isotopes nuclides, which are shorter half-life (or stable), by different photo-nuclear reaction channels (γ,n), (γ,2n), (γ,p), (γ, a), (γ,d). A simulation code has been written using MATLAB for conducting calculations of reduction and residual. The results showed that gamma-ray fluxes below 1017 [cm-2 s-1] are not adequate to perform effective incinera-tion of 137Cs, and as for gamma flux of 1018 ...


Engineering Of A Multi-Epitope Subunit Vaccine Against Sasrs-Cov-2 Through The Viroinformatic Approach, Aamir Shehzada, Christijogo Sumartono, Jusak Nugraha, Helen Susilowatid, Andi Yasmin Wijayab, Hafiz Ishfaq Ahmad, Wiwiek Tyasningsih, Fedik Abdul Rantam May 2022

Engineering Of A Multi-Epitope Subunit Vaccine Against Sasrs-Cov-2 Through The Viroinformatic Approach, Aamir Shehzada, Christijogo Sumartono, Jusak Nugraha, Helen Susilowatid, Andi Yasmin Wijayab, Hafiz Ishfaq Ahmad, Wiwiek Tyasningsih, Fedik Abdul Rantam

Karbala International Journal of Modern Science

The COVID-19 outbreak has infected millions of people worldwide, but no vaccine has been discovered to combat it efficiently. This research aims to design a multi-epitope vaccine using highly efficient B- and T-cell epitopes from the SARS-CoV-2 Surabaya isolate through a viroinformatic approach. First, the putative epitopes were linked together to develop tertiary structures and then docked with toll-like receptor 4 (TLR-4) that demonstrated a robust interaction with a low eigenvalue of 4.816138 e-06. Furthermore, the structure's high immunogenic response was observed and successfully cloned into the expression vector pET28a (+). This implies that the designed vaccine can prove ...


Smart Grid Control: Demand Side Management In Household Refrigerators As A Tool For Load Shifting, Anogh Utkalika Zaman, James Doyle May 2022

Smart Grid Control: Demand Side Management In Household Refrigerators As A Tool For Load Shifting, Anogh Utkalika Zaman, James Doyle

Macalester Journal of Physics and Astronomy

With improved supply of renewable sources of energy the focus has shifted away from simply producing clean energy to efficient consumption of energy. Until cheaper methods of energy storage are developed, Demand Side Management (DSM) is the best option for maximising energy efficiency. This paper proposes a method of turning regular refrigerators into smart demand response fridges. First, we develop an algorithm that accounts for small fluctuations in price and switches the device for optimal performance and lowered running cost. Then, we use longer price fluctuations to predict suitable times for pre-cooling and investigate the reduction in price as a ...


Twisting Lasers With The Faraday Effect, Harrison Werrell May 2022

Twisting Lasers With The Faraday Effect, Harrison Werrell

Macalester Journal of Physics and Astronomy

Our objective with this project was to create a system and procedure to quantify the magnetization of a material with polarized light by using the Faraday Effect, where the light is rotated according to the magnetization. This type of system has seen use in technologies such as magneto-optical drives and optical isolators, and is part of the study of optical materials, along with the similar MagnetoOptical Kerr Effect. Our system, specifically, is intended to be used as part of an advanced Physics Lab in the future. It uses an electromagnet to magnetize a sample, and a laser to observe the ...


Electrical Analysis Of A Pem Electrolysis Cell, Joey Wehrley, James Doyle May 2022

Electrical Analysis Of A Pem Electrolysis Cell, Joey Wehrley, James Doyle

Macalester Journal of Physics and Astronomy

Polymer Electrolyte Membrane (PEM) electrolysis is a form of electrolysis that is heavily used in commercial capacities. It functions by using a membrane and an electric charge in order to perform electrolysis water, splitting it into its component parts - Hydrogen and Oxygen. These parts can then be used in a number of different applications, including reversing the electrolysis process to regenerate some energy in the form of electricity. During this experiment, multiple currents were run through a PEM cell, and voltages across the membrane were measured. It was found that a standard R/C charging model can be fit to ...


The Interaction Of Topological Defects In Anisotropically-Elastic Nematic Liquid Crystals, Carter J. Swift May 2022

The Interaction Of Topological Defects In Anisotropically-Elastic Nematic Liquid Crystals, Carter J. Swift

Macalester Journal of Physics and Astronomy

Topological defects are very well understood so long as the medium in which they exist is isotropically-elastic. They lead to director fields which are easy to calculate and superpose linearly so that a system with any number of defects is analytically treatable. They also have an interaction which is simple in form and can be accurately described by the Peach-Koehler force. In an anisotropically-elastic medium, however, such defects are very poorly understood outside of the single-defect case which was solved by Dzyaloshinskii. In this project, numerical and approximate analytical techniques are applied in order to better understand the interaction between ...


Neutrino Oscillations In The Presence Of A Magnetic Field, Chinhsan Sieng May 2022

Neutrino Oscillations In The Presence Of A Magnetic Field, Chinhsan Sieng

Macalester Journal of Physics and Astronomy

We calculate oscillation probabilities in the presence of an external magnetic field in a one-generation neutrino framework that includes both Majorana and Dirac mass terms. First, we write down the Euler-Lagrange equations and obtain a system of eight differential equations coupling together eight different neutrino states that can be distinguished by helicity, chirality, and particle/antiparticle-ness. We then solve this system of differential equations in various special cases, exhibiting different types of oscillations. When the magnetic field is in the direction of momentum, there are only four oscillation channels as helicity flip is forbidden. We observe that chirality flips are ...


The Impact Of Initial Abundances On Modeling The Weak S-Process, Lev S. Serxner May 2022

The Impact Of Initial Abundances On Modeling The Weak S-Process, Lev S. Serxner

Macalester Journal of Physics and Astronomy

No abstract provided.


The Survey Of Hi In Extremely Low-Mass Dwarfs: New Results From Vla Imaging, Francesco Pecere, John M. Cannon, Damen Beverlin, Jackson Codd May 2022

The Survey Of Hi In Extremely Low-Mass Dwarfs: New Results From Vla Imaging, Francesco Pecere, John M. Cannon, Damen Beverlin, Jackson Codd

Macalester Journal of Physics and Astronomy

We present new HI spectral line imaging of 19 galaxies in the “Survey of HI in Extremely Low-mass Dwarfs” (SHIELD) acquired for Large Program VLA/ 20A-330. Using the National Radio Astronomy Observatory’s Karl G. Jansky Very Large Array (VLA) in the C configuration, we produce images of the neutral interstellar medium (HI) on angular scales of 15 to 20 arcseconds (corresponding to physical resolutions of 200 to 1100 parsecs). The three-dimensional cubes probe the morphology and kinematics of the gas at a range of spatial and spectral resolutions. The cubes were collapsed to produce two-dimensional moment maps (representing HI ...


Hunting For Fast Radio Bursts From Messier 82: Exploring The Frb--Magnetar Connection, Susie Paine May 2022

Hunting For Fast Radio Bursts From Messier 82: Exploring The Frb--Magnetar Connection, Susie Paine

Macalester Journal of Physics and Astronomy

Fast radio bursts (FRBs) are short-duration radio pulses of cosmological origin. Among the most common sources predicted to explain this phenomenon are bright pulses from a class of extremely highly magnetized neutron stars known as magnetars. In 2020, a Galactic magnetar produced an FRB-like burst, allowing researchers to constrain the Galactic magnetar burst rate. We assume that the magnetar burst rate scales with star formation rate and test an important prediction for similar bursts in nearby galaxies. Messier 82 (M82) has a star formation rate 40 times that of the Milky Way, implying that the magnetar burst rate would be ...


Finite-Difference-Time-Domain Simulation Of Ultrafast Experiments, Alpha Ma May 2022

Finite-Difference-Time-Domain Simulation Of Ultrafast Experiments, Alpha Ma

Macalester Journal of Physics and Astronomy

The Finite-Difference-Time-Domain (FDTD) method is a numerical method that calculates electric fields or magnetic fields by interleaving them in space and time. Using a python package called “MEEP”, I was able to write optical simulations of ultrafast experiments, especially the Terahertz Pump-Probe experiments. The goal of this project was to use FDTD simulation to measure the transmission of an electro-magnetic pulse passing through a thin film of conducting material on a dielectric substrate in order to study the characteristic conductivity of potential solar cell materials.


Molecular Line Search In Archival Alma Imaging Of M87, Xueyi Li May 2022

Molecular Line Search In Archival Alma Imaging Of M87, Xueyi Li

Macalester Journal of Physics and Astronomy

We present a molecular line search in spectral imaging of the elliptical galaxy M87 using archival data from the Atacama Large Millimeter/sub-millimeter Array (ALMA). The primary goal of this project is to verify and characterize possible CO transition lines, which can be used for future studies to determine the dynamics of the system, or the mass of the supermassive black hole (BH) in the center of the galaxy. After performing extensive atmospheric modeling, we found that most of the absorption features have a corresponding atmospheric ozone transition, so it is unlikely that these features are either Galactic or extragalactic ...


Lie Algebras And The Poincare Group, Jack Hempel Costello May 2022

Lie Algebras And The Poincare Group, Jack Hempel Costello

Macalester Journal of Physics and Astronomy

This paper will discuss my research with
Professor Tonnis ter Veldhuis on the Poincare Group
and other similar algebraic approaches based on the
Minkowski Metric. This paper will begin with an
introduction discussing group theory and expand on its
specific applications in theoretical physics.


Simulating Interactions Between Coronal Mass Ejections, Damen S. Beverlin, Tatiana Niembro May 2022

Simulating Interactions Between Coronal Mass Ejections, Damen S. Beverlin, Tatiana Niembro

Macalester Journal of Physics and Astronomy

Coronal mass ejections (CMEs) launch large amounts of plasma and magnetic fields into the interplanetary medium. Under the right initial conditions, this ejecta can reach Earth and cause issues with electronic devices. As such, we would like to have an accurate model that depicts how these CMEs propagate as they leave the sun. By using fluid dynamics and one-minute resolution in-situ solar wind data, we sought to simulate CME plasma propagation with analytical and numerical models. Because the interstellar medium contains other material and other events happen on the sun simultaneously, CMEs can interact with each other and other ejecta ...


Custom Calibration And Correction Of Photoemission Electron Microscope Images Using Graphene, Henry Bell May 2022

Custom Calibration And Correction Of Photoemission Electron Microscope Images Using Graphene, Henry Bell

Macalester Journal of Physics and Astronomy

The Photoemission Electron Microscope (PEEM) is a full-field electron microscope that utilizes the photoelectric effect to image a surface. Due to a spatial resolution on the order of 10 nanometers and its ability to image both the morphology of a surface and its band structure, it is a useful tool for understanding the properties of materials for use in electronic devices. To correct for random sample misalignment and the experimental frame of reference in the spectroscopy mode of the PEEM, the 3D dataset must be rotated in both the momentum and energy coordinates which requires pixel calibration and energy alignment ...


Knocking Down Nox: Examining The Effects Of Transportation Electrification On Urban Ozone Production In The South Coast Air Basin, Jason Beal May 2022

Knocking Down Nox: Examining The Effects Of Transportation Electrification On Urban Ozone Production In The South Coast Air Basin, Jason Beal

Macalester Journal of Physics and Astronomy

With last year’s commitment to all in-state sales of new passenger cars and trucks being zero-emission by 2035 (California Executive Order N-79-20), California is leading the charge for transportation electrification in the United States. Despite being at the forefront of climate change management and mitigation, California has some of the worst air quality in the nation. While primarily motivated by a desire to reduce carbon dioxide emissions and reliance on fossil fuels, transportation electrification will also have a significant impact on local air quality. The goal of this study is to quantify and qualify this impact in the context ...


Monolithically Integrated Microscale Pressure Sensor On An Optical Fiber Tip [U.S. Patent Us11326970b2], Jeremiah C. Williams, Hengky Chandrahalim May 2022

Monolithically Integrated Microscale Pressure Sensor On An Optical Fiber Tip [U.S. Patent Us11326970b2], Jeremiah C. Williams, Hengky Chandrahalim

Faculty Publications

A passive microscopic Fabry-Pérot Interferometer (FPI) pressure sensor includes an optical fiber and a three-dimensional microscopic optical enclosure. The three-dimensional microscopic optical enclosure includes tubular side walls having lateral pleated corrugations and attached to a cleaved tip of the optical fiber to receive a light signal. An optically reflecting end wall is distally engaged to the tubular side walls to enclose a trapped quantity of gas that longitudinally positions the optically reflecting end wall in relation to ambient air pressure, changing a distance traveled by a light signal reflected back through the optical fiber.


Large Earthquakes' Effect On The Ionosphere, Aaron Houston May 2022

Large Earthquakes' Effect On The Ionosphere, Aaron Houston

Physics Capstone Projects

The ionosphere is a part of the Earth’s atmosphere that stretches from 80 – 600 kilometers. Gases in this area are ionized which creates a range of free electrons that make up the plasma of the ionosphere. A group of these electrons is known as Total Electron Content (TEC), which is responsible for signal delays between satellites in orbit and their GPS receivers on the surface. Using this delay, the TEC in a specific region can be calculated. This helps in GPS error analysis. During the earthquake in Japan on March 11, 2011, there was allegedly a noticeable jump in ...


Improving The Efficiency Of The Preconditioning Of Iterative Solutions To The Kinetic Equation, D. Caleb Price May 2022

Improving The Efficiency Of The Preconditioning Of Iterative Solutions To The Kinetic Equation, D. Caleb Price

Physics Capstone Projects

To achieve the reality of fusion, a greater understanding of plasma is required. The kinetic equation can be evolved simultaneously alongside the fluid equations to solve for kinetic closures. NIMROD performs this with numerical solvers where the General Minimum Residual (GMRES) solver becomes more efficient with a preconditioning matrix as input. Using a GPU-enabled library, the efficiency of GPU offloading to the preconditioning step was tested. A significant decrease in the factoring time of preconditioning matrix was observed. This suggests that the allocation of GPUs is worth investigating for NIMROD’s own benefit, but also anyone seeking to improve the ...


A Machine Learning Based Approach To Detect The Ethereum Fraud Transactions With Limited Attributes, Rabia Musheer Aziz, Mohammed Farhan Baluch, Sarthak Patel, Pavan Kumar May 2022

A Machine Learning Based Approach To Detect The Ethereum Fraud Transactions With Limited Attributes, Rabia Musheer Aziz, Mohammed Farhan Baluch, Sarthak Patel, Pavan Kumar

Karbala International Journal of Modern Science

Ethereum smart contracts have recently received new commercial applications and a lot of attention from the scientific community. Ethereum eliminates the requirement for a trusted third party by allowing untrusted parties to expose contract details in computer code. Nonetheless, as online commerce grows, plenty of fraudulent activities, such as money laundering, bribery, and phishing, emerge as major threats to trade security. For correctly recognizing fraudulent transactions, this paper developed a Light Gradient Boosting Machine (LGBM) technique-based model. The modified LGBM model optimized the parameters of Light GBM using the Euclidean distant structured estimation approach. This paper also examines the performance ...


A Bi-Level Data Lowering Method To Minimize Transferring Big Data In The Sensors Of Iot Applications, Ali Kadhum M. Al-Qurabat, Ali Kadhum Idrees, Abdallah Makhoul, Chady Abou Jaoude May 2022

A Bi-Level Data Lowering Method To Minimize Transferring Big Data In The Sensors Of Iot Applications, Ali Kadhum M. Al-Qurabat, Ali Kadhum Idrees, Abdallah Makhoul, Chady Abou Jaoude

Karbala International Journal of Modern Science

In the IoT era, the number of devices connected to it continues to grow significantly. This can lead to an increase in the amount of reported data by these IoT devices. The reported data by the Sensor Nodes (SNs) to the Gateway (GW) drives these IoT sensors to consume their energy and storage. These problems can be solved by reducing the amount of data in the source nodes in order to reduce both the amount of energy consumed and the amount of storage required. Energy consumption represents one aspect of the Quality of Service (QoS) in the sensor nodes of ...


An Economical Source For Peroxidase: Maize Cobs, Hathama Razooki Hasan, Ali Waleed Al- Ani May 2022

An Economical Source For Peroxidase: Maize Cobs, Hathama Razooki Hasan, Ali Waleed Al- Ani

Karbala International Journal of Modern Science

According to the current situation of peroxidase (POD), the relevant studies on this enzyme indicated its importance as a tool in clinical biochemistry and different industrial fields. Most of these studies used the fruits and vegetables as source of this enzyme. So that in order to couple the growing requirements for POD with the recent demands for reduc-ing disposal volume by recycling the plant waste, the aim of the present study was to extract POD through management of municipal bio-waste of Iraqi maize species. A simple, green and economical method was used to extract this enzyme. Our results revealed that ...