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Full-Text Articles in Physics

Differential Elliptic Flow Analysis Of Hadrons With Different Wuark Content In Simulated Pp Collisions, Elhussein Osama Jun 2024

Differential Elliptic Flow Analysis Of Hadrons With Different Wuark Content In Simulated Pp Collisions, Elhussein Osama

Theses and Dissertations

According to current physics theories, it is assumed that in the first microsecond after the big bang, the universe was in a state of matter called Quark-Gluon Plasma (QGP), where the fundamental consistent of matters (quarks and leptons), were highly energetic, and floating around freely. Searching for such phase of matter; as the possible earliest signatures after the big bang, and among many other interesting experimental measurements, the jet quenching and elliptic flow are the most important ones, in the heavy ion collisions at the Relativistic Heavy Ion Collider (RHIC) and the Large Hadron Collider (LHC) experiments.

The azimuthal anisotropy …


Divergence-Free Tensor Densities In Two Dimensions, Tyler Hansen May 2024

Divergence-Free Tensor Densities In Two Dimensions, Tyler Hansen

All Graduate Theses and Dissertations, Fall 2023 to Present

In physics, a common method for exploring the way a physical system changes over time is to look at the system’s energy. Roughly speaking, the energy in these systems are either motion-based (kinetic energy, a bullet in flight) or position-based (potential energy, a rock sitting at the top of a hill). The difference between the system’s total kinetic and potential energies is quantified by an expression called the Lagrangian. Using a special procedure, this Lagrangian is massaged to produce a group of equations called the Euler-Lagrange equations; if the initial configuration of the system is provided, the solution to these …


Dynamical Architectures Of S-Type Transiting Planets In Binaries. I. Target Selection Using Hipparcos And Gaia Proper Motion Anomalies, J. Zhang, L. M. Weiss, D. Huber, Eric L.N. Jensen, T. D. Brandt, K. Collins, D. M. Conti, H. Isaacson, P. Lewin, G. Marino, B. Massey, F. Murgas, E. Palle, D. J. Radford, H. M. Relles, G. Srdoc, C. Stockdale, T.-G. Tan, G. Wang Mar 2024

Dynamical Architectures Of S-Type Transiting Planets In Binaries. I. Target Selection Using Hipparcos And Gaia Proper Motion Anomalies, J. Zhang, L. M. Weiss, D. Huber, Eric L.N. Jensen, T. D. Brandt, K. Collins, D. M. Conti, H. Isaacson, P. Lewin, G. Marino, B. Massey, F. Murgas, E. Palle, D. J. Radford, H. M. Relles, G. Srdoc, C. Stockdale, T.-G. Tan, G. Wang

Physics & Astronomy Faculty Works

The effect of stellar multiplicity on planetary architecture and orbital dynamics provides an important context for exoplanet demographics. We present a volume-limited catalog of up to 300 pc of 66 stars hosting planets and planet candidates from Kepler, K2, and TESS with significant Hipparcos-Gaia proper motion anomalies, which indicates the presence of companions. We assess the reliability of each transiting planet candidate using ground-based follow-up observations, and find that the TESS Objects of Interest (TOIs) with significant proper anomalies show nearly four times more false positives due to eclipsing binaries compared to TOIs with marginal proper anomalies. In addition, we …


Light Curve And Hardness Tests For Millilensing In Grb 081122a, Grb 081126a, Grb 110517b, And Grb 210812a, Oindabi Mukherjee, Robert J. Nemiroff Mar 2024

Light Curve And Hardness Tests For Millilensing In Grb 081122a, Grb 081126a, Grb 110517b, And Grb 210812a, Oindabi Mukherjee, Robert J. Nemiroff

Michigan Tech Publications, Part 2

Analyses are given on four recent gravitational millilensing claims on gamma-ray bursts (GRBs): GRB 081122A, GRB 081126A, GRB 110517B, and GRB 210812A. Two tests, a light curve similarity test and a hardness similarity test, compare different temporal sections of a single GRB to see if they are statistically similar. The hardness similarity test shows that the ratio between the second and the first emission episodes in each energy channel differed from the same ratio averaged over all energy channels at above 90 per cent confidence level in GRB 081122A. Additionally, the light curve similarity test applied to GRB 081122A, GRB …


First-Principles Study Of Hydrogen Storage Application Of Ti3c2tx Monolayer Mxene, Yi Zhi Chu, Kah Chun Lau Feb 2024

First-Principles Study Of Hydrogen Storage Application Of Ti3c2tx Monolayer Mxene, Yi Zhi Chu, Kah Chun Lau

Michigan Tech Publications, Part 2

MXene, with its high aspect ratio and adjustable surface properties, has garnered significant attention in the realm of hydrogen storage research. For the first time, considering a ternary/quaternary mixed terminated MXene surface, the authors have investigated comprehensively the hydrogen storage potential of two-dimensional (2D) titanium carbide Ti3C2Tx monolayer MXene using density functional theory (DFT). By considering mixed terminated surfaces, this study indicated the locally induced dipole due to the mixed termination is beneficial in facilitating hydrogen adsorption with stronger average adsorption energies than that of the uniform F-/O-/OH-/H-terminated surfaces. The authors estimated a compelling average H2 surface adsorption energy on …


Investigations Of The Eutectic Formation And Skin Rejuvenation By Hyaluronan - Kojic Acid Dipalmitate System, Syed Waqar Hussain Shah, Sumbal Imran, Iram Bibi, Kashif Ali, Nadia Bashir Feb 2024

Investigations Of The Eutectic Formation And Skin Rejuvenation By Hyaluronan - Kojic Acid Dipalmitate System, Syed Waqar Hussain Shah, Sumbal Imran, Iram Bibi, Kashif Ali, Nadia Bashir

Karbala International Journal of Modern Science

Eutectic phenomenon has been investigated in binary system based on biopolymer hyaluronan (HN) and kojic acid dipalmitate (KAD). Solid-liquid phase diagram showed a significant dependence of melting points on weight fraction of KAD up to KAD < 0.5. A negligible regain to melting temperature of pure KAD occurred later. Simulations of molecular mechanics using a four-unit segment of HN and KAD revealed the interaction between carbonyl of KAD with 4-OH on N-acetylglucosamine unit of oligomer. Infrared vibrational spectroscopy also endorsed the existence of a weakly interacting system. Such behavior was expected due to steric hinderance and rigidity of biopolymer. The thermal decomposition temperature of HN (i.e., 215 °C) was increased to 322 °C in HK50 having HN and KAD in 1:50 w/w. Bioelectric impedance analysis revealed that these green materials could promote skin health in humans.


Synthesis And Characterization Of Renewable Heterogeneous Catalyst Zno Supported Biogenic Silica From Pineapple Leaves Ash For Sustainable Biodiesel Conversion, Nadila Pratiwi, Suriati Eka Putri, Yulia Shinta, Arya Ibnu Batara, Diana Eka Pratiwi, Abd Rahman, Nur Ahmad, Heryanto Heryanto Feb 2024

Synthesis And Characterization Of Renewable Heterogeneous Catalyst Zno Supported Biogenic Silica From Pineapple Leaves Ash For Sustainable Biodiesel Conversion, Nadila Pratiwi, Suriati Eka Putri, Yulia Shinta, Arya Ibnu Batara, Diana Eka Pratiwi, Abd Rahman, Nur Ahmad, Heryanto Heryanto

Karbala International Journal of Modern Science

This study reports on the first case of the low-cost and environmentally friendly ZnO/SiO2 heterogeneous catalyst from pineapple leaves ash (PLA). Catalyst shows excellent performance in catalyzing the transesterification of waste cooking oil (WCO) with methanol for biodiesel conversion. This study focuses on assessing the influence of Zn content on physicochemical characteristics, using XRD, FTIR, SEM, and N2 adsorption-desorption methods. In addition, three different Zn content levels (20, 25, and 30 %wt) were applied. The results showed that all ZnO/SiO2 samples exhibited characteristics suitable for use as catalyst with an average crystallite size of 31.83-34.15 nm, and a surface area …


Low Fine-Tuning With Heavy Higgsinos In Yukawa Unified Susy Guts, Cem Salih Ün Feb 2024

Low Fine-Tuning With Heavy Higgsinos In Yukawa Unified Susy Guts, Cem Salih Ün

Turkish Journal of Physics

The work presented considers a class of minimally constructed Yukawa unified SUSY GUTs - NUHM2 - and explores their implications when their soft supersymmetry breaking Lagrangian is generalized by the nonholomorphic terms which provide extra contributions to the Higgsino mass and couple the supersymmetric scalar fields to the wrong Higgs doublets. With such a simple extension, it can be found several regions with interesting implications which cannot be realized in the usual restricted models. It is observed that the Yukawa unification solutions can be compatible with a relatively light mass spectrum and acceptable low fine-tuning measurements. In the restricted models …


Reheating Constraints To Palatini Coleman-Weinberg Inflation, Nilay Bostan Feb 2024

Reheating Constraints To Palatini Coleman-Weinberg Inflation, Nilay Bostan

Turkish Journal of Physics

In this work, we examine the reheating constraints to symmetry-breaking mechanism, which is associated with Coleman-Weinberg inflation in the early universe. We consider the Coleman-Weinberg inflation potential, where the inflaton has a v ̸= 0 after inflation. Setting Treh = 105 GeV, we first show wreh dependency on ns , r , and N∗ for AV case. Then, we demonstrate the results of ns , r , N∗ , α = dns/d ln k for different reheating temperatures and compare the results with the latest BICEP/Keck data. We also present that ns −r and ns −N∗ planes and the effect …


Comparative Study Between Virgin And Agriculture Soil Radon Activity Concentration And Their Radiological Risks, Hiwa Hamad Azeez Dr., Jahfer Majeed Smail Dr., Hemn Muhammad Salh Dr., Habeeb Hanna Mansour Dr., Saddon Taha Ahmad Prof. Dr., Hawbash H. Hamadamin Karim Dr. Feb 2024

Comparative Study Between Virgin And Agriculture Soil Radon Activity Concentration And Their Radiological Risks, Hiwa Hamad Azeez Dr., Jahfer Majeed Smail Dr., Hemn Muhammad Salh Dr., Habeeb Hanna Mansour Dr., Saddon Taha Ahmad Prof. Dr., Hawbash H. Hamadamin Karim Dr.

Polytechnic Journal

The present study is to compare the radon activity concentration in agricultural and virgin soils from various locations along the Little Zab River (LZR) in the Iraqi Kurdistan region. We conducted 24 measurements of soil samples using long tube techniques equipped with an electric radon detector called RAD7 in our research. The findings revealed that the radon activity concentrations ranged from 37.3 ± 7.52 Bq m-3 to 298.25 ± 50.09 Bq m-3 in virgin soil, and from 33.03 ± 10.85 Bq m-3 to 320.25 ± 34.62 Bq.m-3 in agriculture soil. The annual effective dose was also calculated to be from …


First-Principles Study Of Mxene Properties With Varying Hydrofluoric Acid Concentration, Yi Zhi Chu, Megan Hoover, Patrick Ward, Kah Chun Lau Feb 2024

First-Principles Study Of Mxene Properties With Varying Hydrofluoric Acid Concentration, Yi Zhi Chu, Megan Hoover, Patrick Ward, Kah Chun Lau

Michigan Tech Publications, Part 2

With varying hydrofluoric acid (HF) concentrations under three etching conditions, we presented a comparative study of the effects of both the ordered and randomly ternary mixed terminated Ti3C2Tx surfaces with a wide variation of O/OH/F stoichiometry on the thermodynamic stability and electronic properties. Regardless of the HF concentration, an OH-rich surface is found to be thermodynamically stable and the electrical conductivity of Ti3C2Tx is substantially affected by the OH concentration. The charge density difference and electron localization function demonstrated a significant electron localization at the hydroxyl group on the O/OH/F mixed terminated surface, which could yield a locally induced dipole …


Butterworth Filter To Reduce Reactivity Fluctuations, Daniel Suescún-Díaz, Geraldyne Ule-Duque, Luis E. Cardoso-Páez Feb 2024

Butterworth Filter To Reduce Reactivity Fluctuations, Daniel Suescún-Díaz, Geraldyne Ule-Duque, Luis E. Cardoso-Páez

Karbala International Journal of Modern Science

In this study, we introduce the calculation of reactivity in nuclear reactors. The proposed method uses the Euler-Maclaurin series to approximate the integral in the inverse equation of point kinetics. The approximation is done with the first three terms, the first term represents the approximation of a zero-order sum, the second term the trapezoidal rule and the third term the first Bernoulli number. These three terms improve the approximation, along with an estimate of the neutron density using the prompt jump approximation. To reduce neutron density fluctuations, a second-order Butterworth filter for the reactivity calculation was implemented, which offers the …


Machine Learning Model And Molecular Docking For Screening Medicinal Plants As Hiv-1 Reverse Transcriptase Inhibitors, Muthia Rahayu Iresha, Firdayani Firdayani, Agam Wira Sani, Nihayatul Karimah, Shelvi Listiana, Irfansyah Yudhi Tanasa, Arief Sartono, Ayu Masyita Feb 2024

Machine Learning Model And Molecular Docking For Screening Medicinal Plants As Hiv-1 Reverse Transcriptase Inhibitors, Muthia Rahayu Iresha, Firdayani Firdayani, Agam Wira Sani, Nihayatul Karimah, Shelvi Listiana, Irfansyah Yudhi Tanasa, Arief Sartono, Ayu Masyita

Karbala International Journal of Modern Science

The human immunodeficiency virus type 1 reverse transcriptase (HIV-1 RT) plays a significant role in viral replication and is one of the targets for anti-HIV. However, a mutation in viral strains rapidly developed the resistance of the com-pounds to the protein, reducing the effectiveness of the inhibitors. This work seeks to utilize machine learning-based quantitative structure-activity relationship (QSAR) analysis in combination with molecular docking simulations to forecast the presence of active compounds derived from medicinal plants. Specifically, the objective is to identify com-pounds that have the potential to operate as inhibitors of HIV-1 reverse transcriptase (RT), encompassing both wild-type and …


Beyond Standard Model: Axial Electric Potentials Of Quarks And Neutrinos, Polievkt Perov Feb 2024

Beyond Standard Model: Axial Electric Potentials Of Quarks And Neutrinos, Polievkt Perov

College of Arts & Sciences Faculty Works

The equations of axial electric potentials are presented for our models of quarks and neutrinos as spinning composite structures where up to 3 basic elementary charges are on the axis or rotation and the other N charges are revolving about the axis. The axial potential functions at given point on the axis of rotation were calculated as the sum of electric potentials at that point from all the charges in the structure. We applied these general equations specifically to the models of two types of neutral particles (neutrinos), one with 2 like charges on the axis and the other with …


Two-Photon Absorption And Fluorescence Of Cadmium Sulfide, Jacob Goranson, Gregory J. Taft Feb 2024

Two-Photon Absorption And Fluorescence Of Cadmium Sulfide, Jacob Goranson, Gregory J. Taft

Physics Faculty Publications

The two-photon absorption and fluorescence of bulk cadmium sulfide were studied using 50-fs, 800-nm pulses from an unamplified Ti:sapphire laser. The fluorescence spectrum was measured to have a main peak at 522 nm, and the power of the fluorescence was shown to vary quadratically with the 800-nm beam power. This supports the theory that the fluorescence is excited by two-photon absorption and confirms previous work done with longer duration, higher energy excitation pulses. Pump-probe measurements provided additional confirmation of the two-photon absorption. Measured spectral broadening of the wings of the laser spectrum also was observed, which likely is due to …


Multi-Agent System For Portfolio Profit Optimization For Future Stock Trading, Usha Devi, Mohan R Feb 2024

Multi-Agent System For Portfolio Profit Optimization For Future Stock Trading, Usha Devi, Mohan R

Karbala International Journal of Modern Science

Stock trading highly contributes to the economic growth of the country. The stock trading objective is to earn profits with buy/sell/hold decisions on the set of stocks in the portfolio. The portfolio optimization problem is finding the decision sequence that leads to higher profit and lower risk. Portfolio optimization is challenging due to complex price history patterns and an uncertain environment. Incorrect decisions in stock trading lead to massive losses. The proposed Multi-Agent System for Portfolio Profit Optimization (MASPPO) aims to optimize trading profit and reduce risk with accurate predictions. The proposed model integrates the Fuzzy c-means with the Deep …


Probing Central Spin Decoherence Dynamics Of Electronic Point Defects In Diamond And Silicon, Ethan Que Williams Feb 2024

Probing Central Spin Decoherence Dynamics Of Electronic Point Defects In Diamond And Silicon, Ethan Que Williams

Dartmouth College Ph.D Dissertations

Electron spins of point defects in diamond and silicon can exhibit long coherence times, making them attractive platforms for the physical implementation of qubits for quantum sensing and quantum computing. To realize these technologies, it is essential to understand the mechanisms that limit their coherence. Decoherence of these systems is well described by the central spin model, wherein the central electron spin weakly interacts with numerous electron and nuclear spins in its environment. The dynamics of the resultant dephasing can be probed with pulse electron paramagnetic resonance (pEPR) experiments.

Using a 2.5 GHz pEPR spectrometer built in-house, we performed multi-pulse …


From Norms Taker To Norms Breaker: A Comparative Study Of Turkey’S Nuclear Discourses Before And After The Ostensible Coup Of 2016, Sarah Tzinieris, Zenobia S. Homan, Cem Boke, Amna Javed Feb 2024

From Norms Taker To Norms Breaker: A Comparative Study Of Turkey’S Nuclear Discourses Before And After The Ostensible Coup Of 2016, Sarah Tzinieris, Zenobia S. Homan, Cem Boke, Amna Javed

International Journal of Nuclear Security

This article offers an analysis of public statements made by Turkish government leaders, contrasting official attitudes on nuclear nonproliferation before and after the alleged military coup attempt in 2016. Significant developments in this period include deteriorating democracy and the rule of law in Turkey and the emergence of destabilizing foreign policy differences between Turkey and Western states. President Recep Tayyip Erdoğan also sought to consolidate domestic power and play a more assertive security role in the Middle East. This analysis of official statements reveals a distinct shift in Turkey’s nonproliferation rhetoric after the 2016 coup. In particular, Turkish government ministers …


College Of Natural Sciences 2023 Year-End Publication, College Of Natural Sciences Feb 2024

College Of Natural Sciences 2023 Year-End Publication, College Of Natural Sciences

College of Natural Sciences Newsletters and Reports

Page 1 Dean's Message
Page 3 Department Highlights
Page 4 One Day for State
Page 5 Noble Prize Winner Speaks on Campus
Page 6-7 Faculty Excellence
Page 8-9 Student Excellence
Page 10 Outreach Program
Page 10 Events and Traditions
Page 11 Connections Abroad
Page 12 Student Spotlight
Page 13 Alumni Spotlight
Page 14 First Ever Drone Day
Page 15 Grand Opening of POET Bioproducts Center
Page 16 Work Anniversaries


The Fourier–Legendre Series Of Bessel Functions Of The First Kind And The Summed Series Involving 1f2 Hypergeometric Functions That Arise From Them, Jack C. Straton Feb 2024

The Fourier–Legendre Series Of Bessel Functions Of The First Kind And The Summed Series Involving 1f2 Hypergeometric Functions That Arise From Them, Jack C. Straton

Physics Faculty Publications and Presentations

The Bessel function of the first kind JN(kx) is expanded in a Fourier–Legendre series, as is the modified Bessel function of the first kind IN(kx). The purpose of these expansions in Legendre polynomials was not an attempt to rival established numerical methods for calculating Bessel functions but to provide a form for JN(kx) useful for analytical work in the area of strong laser fields, where analytical integration over scattering angles is essential. Despite their primary purpose, one can easily truncate the series at 21 terms to provide 33-digit accuracy that matches the IEEE extended precision in …


Exciton Dynamics, Interaction, And Transport In Monolayers Of Transition Metal Dichalcogenides, Saroj Chand Feb 2024

Exciton Dynamics, Interaction, And Transport In Monolayers Of Transition Metal Dichalcogenides, Saroj Chand

Dissertations, Theses, and Capstone Projects

Monolayers Transition metal dichalcogenides (TMDs) have attracted much attention in recent years due to their promising optical and electronic properties for applications in optoelectronic devices. The rich multivalley band structure and sizable spin-orbit coupling in monolayer TMDs result in several optically bright and dark excitonic states with different spin and valley configurations. In the proposed works, we have developed experimental techniques and theoretical models to study the dynamics, interactions, and transport of both dark and bright excitons.

In W-based monolayers of TMDs, the momentum dark exciton cannot typically recombine optically, but they represent the lowest excitonic state of the system …


A Causal Inference Approach For Spike Train Interactions, Zach Saccomano Feb 2024

A Causal Inference Approach For Spike Train Interactions, Zach Saccomano

Dissertations, Theses, and Capstone Projects

Since the 1960s, neuroscientists have worked on the problem of estimating synaptic properties, such as connectivity and strength, from simultaneously recorded spike trains. Recent years have seen renewed interest in the problem coinciding with rapid advances in experimental technologies, including an approximate exponential increase in the number of neurons that can be recorded in parallel and perturbation techniques such as optogenetics that can be used to calibrate and validate causal hypotheses about functional connectivity. This thesis presents a mathematical examination of synaptic inference from two perspectives: (1) using in vivo data and biophysical models, we ask in what cases the …


Integral Representations Over Finite Limits For Quantum Amplitudes, Jack C. Straton Feb 2024

Integral Representations Over Finite Limits For Quantum Amplitudes, Jack C. Straton

Physics Faculty Publications and Presentations

We extend previous research to derive three additional M-1-dimensional integral representations over the interval [0,1]" The prior version covered the interval [0,∞]" role="presentation position: relative;">[0,∞][0,∞]. This extension applies to products of M Slater orbitals, since they (and wave functions derived from them) appear in quantum transition amplitudes. It enables the magnitudes of coordinate vector differences (square roots of polynomials) |x1−x2|=x12−2x1x2cosθ+x22" to be shifted from disjoint products of functions into a single quadratic form, allowing for the completion of its square. The M-1-dimensional integral representations of M Slater orbitals that both this extension and the prior version introduce …


The Roaring Lion Of Berlin: The Life, Thought, And Influence Of Eugen Dühring, Arden Roy Jan 2024

The Roaring Lion Of Berlin: The Life, Thought, And Influence Of Eugen Dühring, Arden Roy

Undergraduate Research Symposium

The life and influence of 19th-century German polymath Eugen Dühring remain but a mere footnote in the history of ideas, being primarily relegated to the status of little more than a theoretical rival to Marxism in the German socialist movement and the occasional object of Freidrich Nietzsche's rhetorical flogging. Despite the current consensus on the subject, Eugen Dühring was a scholar of vast, remarkable learnedness, contributing greatly to philosophy, economics, and the natural sciences. The aim of this talk will be to clear the fog surrounding the life and work of the controversial blind scholar and give an account of …


On The Exact Helium Wave Function Expansion, Ii, An Exponential Modulated Form, Carl W. David Jan 2024

On The Exact Helium Wave Function Expansion, Ii, An Exponential Modulated Form, Carl W. David

Chemistry Education Materials

A 11S wave function’s expansion for 2 electron atoms and ions is proposed employing an appropriate exponential factor and Fock’s logarithmic terms. The leading coefficient’s are presented.


Non-Hermitian Physics Achieved Via Non-Local Gilbert Damping, Trevor Joshua Macintosh Jan 2024

Non-Hermitian Physics Achieved Via Non-Local Gilbert Damping, Trevor Joshua Macintosh

Electronic Theses and Dissertations

In this thesis, we study a simple model for a ferromagnet starting with Heisenberg exchange interaction including the effects of dissipation. Gilbert damping is consid- ered and generalized from an on-site term to include non-local damping interactions between neighbouring spins. The strength of the damping interaction between neigh- bours can be tuned individually to provide the freedom to change the parameters of the system and explore the range of possible non-Hermitian behaviours. We consider the example of a honeycomb lattice ferromagnet featuring Dirac cones and two sub- lattices and analyse the resulting spectra and eigenstates. Under periodic boundary conditions, we …


Superconductivity Of Amorphous And Crystalline Re–Lu Films, Serafim Teknowijoyo, Armen Gulian Jan 2024

Superconductivity Of Amorphous And Crystalline Re–Lu Films, Serafim Teknowijoyo, Armen Gulian

Mathematics, Physics, and Computer Science Faculty Articles and Research

We report on superconducting properties of a novel material: rhenium-lutetium films. Different compositions of RexLu binary are explored from x ≈ 3.8 to close to pure Re stoichiometry. The highest critical temperature, up to 7 K, is obtained for x ≈ 10.5 in accordance with electron dispersive spectroscopy results. Depending on the deposition conditions, polycrystalline or amorphous films are obtainable, both of which are interesting for practical use. Crystalline structure of polycrystalline phase is identified as a non-centrosymmetric superconductor using grazing incidence x-ray diffractometry. Superconducting properties were characterized both resistively and magnetically. Magnetoresistivity and AC/DC susceptibility measurements allowed …


Year-2 Progress Report On Numerical Methods For Bgk-Type Kinetic Equations, Steven M. Wise, Evan Habbershaw Jan 2024

Year-2 Progress Report On Numerical Methods For Bgk-Type Kinetic Equations, Steven M. Wise, Evan Habbershaw

Faculty Publications and Other Works -- Mathematics

In this second progress report we expand upon our previous report and preliminary work. Specifically, we review some work on the numerical solution of single- and multi-species BGK-type kinetic equations of particle transport. Such equations model the motion of fluid particles via a density field when the kinetic theory of rarefied gases must be used in place of the continuum limit Navier-Stokes and Euler equations. The BGK-type equations describe the fluid in terms of phase space variables, and, in three space dimensions, require 6 independent phase-space variables (3 for space and 3 for velocity) for each species for accurate simulation. …


Evanescent Wave Quartz-Enhanced Photoacoustic Spectroscopy Employing A Side-Polished Fiber For Methane Sensing, Cian F. Twomey, Gabriele Biagi, Albert A. Ruth, Marilena Giglio, Vincenzo Spagnolo, Liam O'Faolain, Anton J. Walsh Jan 2024

Evanescent Wave Quartz-Enhanced Photoacoustic Spectroscopy Employing A Side-Polished Fiber For Methane Sensing, Cian F. Twomey, Gabriele Biagi, Albert A. Ruth, Marilena Giglio, Vincenzo Spagnolo, Liam O'Faolain, Anton J. Walsh

Cappa Publications

We present an all-fiber-based laser gas analyzer (LGA) employing quartz-enhanced photoacoustic spectroscopy (QEPAS) and a side-polished fiber (SPF). The LGA comprises a custom quartz tuning fork (QTF) with 0.8 mm prong spacing, two acoustic micro-resonators (mR) located on either side of the prong spacing, and a single-mode fiber containing a 17 mm polished section passing through both mRs and QTF. The SPF polished face is positioned to enable the evanescent wave (EW) to create a photoacoustic wave and excite the fundamental flexural mode of the QTF. Sensor performance was demonstrated using methane in nitrogen gas mixtures, with CH4" role="presentation" style="box-sizing: …


Radon Plate-Out And The Effects Of Airflow And Electric Charge For Dark Matter Experiments, Faith Fang Jan 2024

Radon Plate-Out And The Effects Of Airflow And Electric Charge For Dark Matter Experiments, Faith Fang

SMU Journal of Undergraduate Research

The Cryogenic Dark Matter Search (SuperCDMS) is an international collaboration designed to search for and detect dark matter particles, which make up ~85% of the matter in the universe. The plate-out, or deposition of naturally occurring radioactive decay byproducts onto surfaces, can create backgrounds that interfere with dark matter detection experiments. In the first series of these experiments, we analyze the amount of radon progeny, 214Pb and 214Bi, that plate-out on polycarbonate samples while controlling factors such as electric charge and airflow. These samples are exposed to radon-spiked nitrogen gas in a polycarbonate wind tunnel to simulate plate-out conditions in …