Digital Commons Network^™

A Computational Approach For The Estimation Of Elastic Behavior Of Metal Matrix Composites, Emmanuel Michalakis

ME 4233/6233 Fundamentals of FEA

Composite materials are being widely used in many industries for their properties and efficiency. The current work presents a computational approach that can estimate the elastic behavior of metal composites and porous materials using finite element models of representative volume elements (RVEs) which have been used to test and design particulate composite materials. The required size of the RVE for the determination of elastic properties, the effects of the elastic modulus fraction Einc/Emat on the homogenized elasticity and the convergence of the homogenized properties E11, E22 and E33 with the size of the RVE is explored.

Search Of The Early O3 Ligo Data For Continuous Gravitational Waves From The Cassiopeia A And Vela Jr. Supernova Remnants, R. Abbott, T. Abbott, K. Ackley, F. Acernese, Teviet Creighton, Mario C. Diaz, Francisco Llamas, Soma Mukherjee, Volker Quetschke, Wenhui Wang

Physics & Astronomy Faculty Publications

We present directed searches for continuous gravitational waves from the neutron stars in the Cassiopeia A (Cas A) and Vela Jr. supernova remnants. We carry out the searches in the LIGO detector data from the first six months of the third Advanced LIGO and Virgo observing run using the weave semicoherent method, which sums matched-filter detection-statistic values over many time segments spanning the observation period. No gravitational wave signal is detected in the search band of 20–976 Hz for assumed source ages greater than 300 years for Cas A and greater than 700 years for Vela Jr. Estimates from simulated …

An Overview Of Approaches To Nuclear Security In Ghana, Raymond Agalga, Paul Atta Amoah, Daniel Nii Adjei, Daniel Frederick Charles, Emmanuel Ofori Darko

International Journal of Nuclear Security

Ghana has significantly improved its nuclear security infrastructure over the years. However, as threats increase by the day and new applications of nuclear and radiological technology are designed and implemented, Ghana must develop a rigid and comprehensive approach to mitigating the negative impacts on its nuclear security while improving prevention, detection, and deterrence of nuclear and radiological terrorism within its geographical space. This paper overviews the approaches adopted by Ghana to build a strong nuclear security regime within the past decade. These include improving legal frameworks for nuclear security by establishing an independent Nuclear Regulatory Authority; assessing nuclear security culture …

Experimental Demonstration Of Continuous Quantum Error Correction, William P. Livingston, Machiel S. Blok, Emmanuel Flurin, Justin Dressel, Andrew N. Jordan, Irfan Siddiqi

Mathematics, Physics, and Computer Science Faculty Articles and Research

The storage and processing of quantum information are susceptible to external noise, resulting in computational errors. A powerful method to suppress these effects is quantum error correction. Typically, quantum error correction is executed in discrete rounds, using entangling gates and projective measurement on ancillary qubits to complete each round of error correction. Here we use direct parity measurements to implement a continuous quantum bit-flip correction code in a resource-efficient manner, eliminating entangling gates, ancillary qubits, and their associated errors. An FPGA controller actively corrects errors as they are detected, achieving an average bit-flip detection efficiency of up to 91%. Furthermore, …

Dispersion In High Temperature Superconductors, Lazar Novakovic

Undergraduate Research Symposium Podium Presentations

Superconductors are used in many different industries: Efficient power transmission, Maglev train, MRIs

Controlling Unequal Surface Energy Results Caused By Test Liquids: The Case Of Uv/O3 Treated Pet, Bilge N. Altay, Paul D. Fleming, Md Arifur Rahman, Alexandra Pekarovicova, Bruce Myers, Cem Aydemir, Arif Karademir

Articles

Ultraviolet/ozone (UV/O3) treatment has been reported to be an effective method to modify properties such as wettability, adhesion or adsorption of plastic surfaces. The change in the surface is measured by contact angle analysis, which employs liquids and their surface tensions (ST) to estimate the surface energy (SE). We found two different practices in the scientific community: (1) the majority of researchers adopted the ST value of liquids from the literature, while (2) other researchers conducted real-time measurements in the lab under ambient conditions prior to SE estimation. To the best of our knowledge, there is no study that compares …

Using Supervised Learning Algorithms As A Follow-Up Method In The Search Of Gravitational Waves From Core-Collapse Supernovae, Javier M. Antelis, Marco Cavaglia, Travis Hansen, Mannuel D. Morales, Claudia Moreno, Soma Mukherjee, Marek J. Szczepańczyk, Michele Zanolin

Physics & Astronomy Faculty Publications

We present a follow-up method based on supervised machine learning (ML) to improve the performance in the search of gravitational wave (GW) bursts from core-collapse supernovae (CCSNe) using the coherent WaveBurst (cWB) pipeline. The ML model discriminates noise from signal events by using a set of reconstruction parameters provided by cWB as features. Detected noise events are discarded yielding a reduction in the false alarm rate (FAR) and the false alarm probability thus enhancing the statistical significance. We tested the proposed method using strain data from the first half of the third observing run of advanced LIGO, and CCSNe GW …

Lattice Dynamics, Mechanical Properties, Electronic Structure And Magnetic Properties Of Equiatomic Quaternary Heusler Alloys Crticoz (Z = Al, Si) Using First Principles Calculations, Eesha Andharia, Hind Alqurashi, Bothina Hamad

Physics Faculty Publications and Presentations

First principles calculations are performed to investigate the thermodynamical stability, dynamical, mechanical, electronic and magnetic properties of CrTiCoZ (Z = Al/Si) novel quaternary Heusler alloys. A Y-type III atomic configuration is found to be the most stable structure for both compounds. The lattice constant values obtained using GGA-PBE approach are 5.9368 Å and 5.7853 Å for CrTiCoAl and CrTiCoSi, respectively. Using the value of elastic moduli for both the compounds, the computed Pugh’s ratio value is 2.5 and 2.7 for CrTiCoAl and CrTiCoSi, respectively, which is higher than 1.75, indicating both the compounds are ductile in nature. The melting temperatures …

Search For Electroweak Production Of Charginos And Neutralinos In Proton-Proton Collisions At √S = 13 Tev, A. Tumasyan

Department of Physics and Astronomy: Faculty Publications

A direct search for electroweak production of charginos and neutralinos is presented. Events with three or four leptons, with up to two hadronically decaying τ leptons, or two same-sign light leptons are analyzed. The data sample consists of 137 fb⁻¹ of proton-proton collisions with a center of mass energy of 13TeV, recorded with the CMS detector at the LHC. The results are interpreted in terms of several simplified models. These represent a broad range of production and decay scenarios for charginos and neutralinos. A parametric neural network is used to target several of the models with large backgrounds. In …

Design And Characterization Of Frequency Tripling Mirrors, Amir Khabbazi Oskouei

Optical Science and Engineering ETDs

Aperiodic stacks of dielectric low- and high-index films can be designed to enhance third-harmonic generation (THG) in reflection of near infrared laser pulses using computer optimization. Numerical and analytical results suggest that the TH energy increases rapidly with increasing number of films and the ratio of the high and low index.

Our optical matrix based THG model that takes into account the full pulse bandwidth predicts conversion efficiencies of about 7% for transform-limited Gaussian pulse bandwidths of 16 nm for mirrors with 45 layers, which exceed those expected from periodic designs. Stability against film thickness fluctuations expected from the deposition …

3d Flow Field Measurements Outside Nanopores, Jeffrey Mc Hugh, Alice L. Thorneywork, Kurt Andresen, Ulrich F. Keyser

Physics and Astronomy Faculty Publications

We demonstrate a non-stereoscopic, video-based particle tracking system with optical tweezers to study fluid flow in 3D in the vicinity of glass nanopores. In particular, we used the quadrant interpolation algorithm to extend our video-based particle tracking to displacements out of the trapping plane of the tweezers. This permitted the study of flow from nanopores oriented at an angle to the trapping plane, enabling the mounting of nanopores on a micromanipulator with which it was then possible to automate the mapping procedure. Mapping of the voltage driven flow in 3D volumes outside nanopores revealed polarity dependent flow fields. This is …

Superfluidity Of Dipolar Excitons In A Double Layer Of Α -T3 With A Mass Term, Oleg L. Berman, Godfrey Gumbs, Gabriel P. Martins, Paula Fekete

Publications and Research

We predict Bose-Einstein condensation and superfluidity of dipolar excitons, formed by electron-hole pairs in spatially separated gapped hexagonal α − T3 (GHAT3) layers. In the α − T3 model, the AB-honeycomb lattice structure is supplemented with C atoms located at the centers of the hexagons in the lattice. We considered the α − T3 model in the presence of a mass term which opens a gap in the energy-dispersive spectrum. The gap opening mass term, caused by a weak magnetic field, plays the role of Zeeman splitting at low magnetic fields for this pseudospin-1 system. The band structure of GHAT3 …

Can Rigorous Metaphorical Thinking Improve Learning Outcomes?, Arian Dovald

Campus Research Month

Theoretical metaphors are a novel way of analyzing theories in physics. Thinking of physical models as theoretical metaphors clarifies the role of language in scientific modeling. They show how theories make connections between concepts, language, and math. I propose a study to measure the effect on learning outcomes of explicit instruction on theoretical metaphors.

The Replacement Rule For Nonlinear Shallow Water Waves, A. Ludu, Z. Zong

Publications

When a (1 + 1)-dimensional nonlinear PDE in real function η(x, t) admits localized traveling solutions we can consider L to be the average width of the envelope, A the average value of the amplitude of the envelope, and V the group velocity of such a solution. The replacement rule (RR or nonlinear dispersion relation) procedure is able to provide a simple qualitative relation between these three parameters, without actually solve the equation. Examples are provided from KdV, C-H and BBM equations, but the procedure appears to be almost universally valid for such (1 + 1)-dimensional nonlinear PDE and their …

Quantification Of Motility In Bacillus Subtilis At Temperatures Up To 84°C Using A Submersible Volumetric Microscope And Automated Tracking, Megan M. Dubay, Nikki Johnston, Mark Wronkiewicz, Jake Lee, Chris Lindensmith, Jay Nadeau

Physics Faculty Publications and Presentations

We describe a system for high-temperature investigations of bacterial motility using a digital holographic microscope completely submerged in heated water. Temperatures above 90°C could be achieved, with a constant 5°C offset between the sample temperature and the surrounding water bath. Using this system, we observed active motility in Bacillus subtilis up to 66°C. As temperatures rose, most cells became immobilized on the surface, but a fraction of cells remained highly motile at distances of >100 μm above the surface. Suspended non-motile cells showed Brownian motion that scaled consistently with temperature and viscosity. A novel open-source automated tracking package was used …

Study Of Deexcitation Intensities To The K-Shell In Iron 55, Eric Helgemo

Honors Theses

55Fe radioactive sources are used for x-ray calibration due to the long half-lives of 2.73 years and the optimal energies of the peaks. The source used in the experiment was generated using Western Michigan University’s Tandem Van de Graff accelerator to produce a 6 MeV proton beam which induced a 55Mn(p, n)55Fe reaction on a 10 μm 55Mn target. The emissions from this target were then measured using a silicon lithium drift x-ray detector to determine the number of instances of deexcitation through kα and kβ modes. The preliminary data discussed showed a lower relative deexcitation rate of 6.67 between …

Volume 13, Payton Davenport, Audrey Lemons, Jacob Shope, Haley Smith, Cassandra Poole, Rachel Cannon, Rachel Boch, Suzanne Stetson

Incite: The Journal of Undergraduate Scholarship

Introduction Dr. Roger A. Byrne, Dean

From the Editor Dr. Larissa “Kat” Tracy

From the Designers Rachel English, Rachel Hanson

The Effect of Compliment Type on the Estimated Value of the Compliment by Payton Davenport, Audrey Lemons, and Jacob Shope

The Imperial Japanese Military: A New Identity in the Twentieth Century, 1853–1922 by Haley Smith

Longwood University’s campus: Human-cultivated Soil has Higher Microbial Diversity than Soil Collected from Wild Sites by Cassandra Poole

Reminiscent Modernism: Poetry Magazine’s Modernist Nostalgia for the Past by Rachel Cannon

Challenges Faced by Healthcare Workers During the COVID-19 Pandemic: A Preliminary Study of Age and …

Long-Term Spectra Of The Blazars Mrk 421 And Mrk 501 At Tev Energies Seen By Hawc, A. Albert, R. Alfaro, C. Alvarez, J. R.Angeles Camacho, J. C. Arteaga-Velázquez, K. P. Arunbabu, D. Huang, P. Huntemeyer, X. Wang, Et. Al.

Michigan Tech Publications, Part 1

The High Altitude Water Cherenkov (HAWC) Gamma-Ray Observatory surveys the very high-energy sky in the 300 GeV to >100 TeV energy range. HAWC has detected two blazars above 11σ, Markarian 421 (Mrk 421) and Markarian 501 (Mrk 501). The observations are comprised of data taken in the period between 2015 June and 2018 July, resulting in ∼1038 days of exposure. In this work, we report the time-averaged spectral analyses for both sources, above 0.5 TeV. Taking into account the flux attenuation due to the extragalactic background light, the intrinsic spectrum of Mrk 421 is described by a power law with …

Student-Developed Laboratory Activities Using Rolling Object On An Inclined Plane To Improve Student Learning, Qing Shao, Joseph Ametepe

Georgia Journal of Science

This work presents an alternative method of teaching undergraduate introductory physics laboratory. Students are presented with an experimental scenario “Rolling object on an inclined plane” and guided to develop their own laboratory activities in a studio-style setting. The overall goal of this alternative approach is to shift part of the learning responsibility to students. Through guided self-developed activities, students establish the connections between different physics concepts. Such a shift makes students active participants in the classroom, allows them to explore ideas independently, and discover through doing the exploring. Furthermore, the pedagogy is aimed at (i) motivating and actively engaging students …

Annual Faculty Research Symposium 2022, Oakwood University

Proceedings

No abstract provided.

Coil-To-Bridge Transitions Of Self-Assembled Water Chains Observed In A Nanoscopic Meniscus, Byung I. Kim, Ryan D. Boehm, Harrison Agrusa

Physics Faculty Publications and Presentations

Ten downward portions in the large oscillatory force–distance curve reported earlier are analyzed to understand a nanoscale water meniscus confined between a sharp probe and a flat substrate in air. The sigmoidal shape of each portion leads to the assumption that the meniscus is made up of n independent transitions of two states: one for a coil state and the other for a bridge state. The analysis reveals that each downward portion occurs due to a coil-to-bridge transition of n self-assembled water chains whose length ranges between 197 and 383 chain units. The transition provides novel insights into water’s unique …

From Naked Spheroids To Disky Galaxies: How Do Massive Disk Galaxies Shape Their Morphology?, Luca Costantin, Pablo G. Pérez-González, Jairo Méndez-Abreu, Marc Huertas-Company, Belén Alcalde Pampliega, Marc Balcells, Guillermo Barro, Daniel Ceverino, Paola Dimauro, Helena Domínguez Sánchez, Néstor Espino-Briones, Anton M. Koekemoer

Pacific Faculty Work

We investigate the assembly history of massive disk galaxies and describe how they shape their morphology through cosmic time. Using SHARDS and HST data, we modeled the surface brightness distribution of 91 massive galaxies at redshift 0.14 < z ≤ 1 in the wavelength range 0.5-1.6 μm, deriving the uncontaminated spectral energy distributions of their bulges and disks separately. This spectrophotometric decomposition allows us to compare the stellar population properties of each component in individual galaxies. We find that the majority of massive galaxies (∼85%) build inside-out, growing their extended stellar disk around the central spheroid. Some bulges and disks could start forming at similar epochs, but these bulges grow more rapidly than their disks, assembling 80% of their mass in ∼0.7 and ∼3.5 Gyr, respectively. Moreover, we infer that both older bulges and older disks are more massive and compact than younger stellar structures. In particular, we find that bulges display a bimodal distribution of mass-weighted ages; i.e., they form in two waves. In contrast, our analysis of the disk components indicates that they form at z ∼1 for both first- and second-wave bulges. This translates to first-wave bulges taking longer to acquire a stellar disk (5.2 Gyr) compared to second-wave, less compact spheroids (0.7 Gyr). We do not find distinct properties (e.g., mass, star formation timescale, and mass surface density) for the disks in both types of galaxies. We conclude that the bulge mass and compactness mainly regulate the timing of the stellar disk growth, driving the morphological evolution of massive disk galaxies.

Microscopic Nuclei Classification, Segmentation, And Detection With Improved Deep Convolutional Neural Networks (Dcnn), Md Zahangir Alom, Vijayan K. Asari, Anil Parwani, Tarek M. Taha

Electrical and Computer Engineering Faculty Publications

Background Nuclei classification, segmentation, and detection from pathological images are challenging tasks due to cellular heterogeneity in the Whole Slide Images (WSI). Methods In this work, we propose advanced DCNN models for nuclei classification, segmentation, and detection tasks. The Densely Connected Neural Network (DCNN) and Densely Connected Recurrent Convolutional Network (DCRN) models are applied for the nuclei classification tasks. The Recurrent Residual U-Net (R2U-Net) and the R2UNet-based regression model named the University of Dayton Net (UD-Net) are applied for nuclei segmentation and detection tasks respectively. The experiments are conducted on publicly available datasets, including Routine Colon Cancer (RCC) classification and …

Nano-Fabricated Atomic Waveguides For Inertial Measurements, Adrian S. Orozco

Physics & Astronomy ETDs

Atom-based inertial measurement systems can measure acceleration and rotation very precisely in the laboratory. The central element of these systems is atom interferometry where the phase shifts are sensitive to inertial forces experienced by the atom. This phenomenon has been used to make atom-based gravimeters, gradiometers, and gyroscopes. Recent effort has been made to make these systems more compact which require small size, light weight, and low power (SWaP). Nano-fabricated waveguides, such as photonic waveguides or optical nanofibers, offer a promising avenue to meet these goals. They have dimensions comparable to the guided light’s wavelength producing a mode that not …

Tuning Properties Of Topological Insulators: An Ab-Initio Approach, Karunya Shailesh Shirali

LSU Doctoral Dissertations

This thesis develops a first-principles based approach to explore the tuning of topological properties of the tetradymite topological insulators. We begin by setting up a framework to systematically obtain the bulk and surface properties of topological insulators, treating the structural and electronic properties on an equal footing. We determine a consistent method for including the van der Waals interactions, which are responsible for the weak coupling between sets of atomic layers in this family of layered materials, which is important in obtaining accurate structural properties. We obtain close agreement with experimental values for both the bulk and surface states.

To …

Synthesis And Characterization Of Chiral Magnetic Oxide: Mnmoteo6, Chase Hames, August Meads

Symposium of Student Scholars

The chiral materials lack mirror reflection symmetry in their crystal structures like right and left hands. Such materials often host unique non-collinear or topological magnetic textures such as magnetic skyrmions. If such magnetic textures are formed in insulating oxides with coupled electric and magnetic properties, then such magnetic structures can be controlled and manipulated using electric fields rather than electric current. With this motivation, we are synthesizing and characterizing chiral materials belonging to MMoTeO₆ (M=Mn, Co, Fe, Cu, Ni) family. I will discuss about the phase formation and solid-state synthesis of MnTeMoO₆ along with its structural, electrical and …

Spreading Rates Of Bacterial Colonies Depend On Substrate Stiffness And Permeability, Alison Patteson, Merrill Asp, Minh H. Thanh, Danielle A. Germann, Robert J. Carroll, Alana Franceski, Roy D. Welch, Arvind Gopinath

Physics - All Scholarship

The ability of bacteria to colonize and grow on different surfaces is an essential process for biofilm development. Here, we report the use of synthetic hydrogels with tunable stiffness and porosity to assess physical effects of the substrate on biofilm development. Using time-lapse microscopy to track the growth of expanding Serratia marcescens colonies, we find that biofilm colony growth can increase with increasing substrate stiffness, unlike what is found on traditional agar substrates. Using traction force microscopy-based techniques, we find that biofilms exert transient stresses correlated over length scales much larger than a single bacterium, and that the magnitude of …

Using Supervised Learning Algorithms As A Follow-Up Method In The Search Of Gravitational Waves From Core-Collapse Supernovae, Javier M. Antelis, Marco Cavaglia, Travis Hansen, Manuel D. Morales, Claudia Moreno, Soma Mukherjee, Marek J. Szczepańczyk, Michele Zanolin

Physics Faculty Research & Creative Works

We present a follow-up method based on supervised machine learning (ML) to improve the performance in the search of gravitational wave (GW) bursts from core-collapse supernovae (CCSNe) using the coherent WaveBurst (cWB) pipeline. The ML model discriminates noise from signal events by using a set of reconstruction parameters provided by cWB as features. Detected noise events are discarded yielding a reduction in the false alarm rate (FAR) and the false alarm probability thus enhancing the statistical significance. We tested the proposed method using strain data from the first half of the third observing run of advanced LIGO, and CCSNe GW …

Building-Block Approach To The Discovery Of Na8mn2(Ge2se6)2: A Polar Chalcogenide Exhibiting Promising Harmonic Generation Signals With A High Laser-Induced Damage Threshold, Srikanth Balijapelly, Andrew J. Craig, Jeong Bin Cho, Joon I. Jang, Kartik Ghosh, Jennifer A. Aitken, Aleksandr V. Chernatynskiy, Amitava Choudhury

Physics Faculty Research & Creative Works

A new polar quaternary chalcogenide, Na8Mn2(Ge2Se6)2, has been synthesized using the building-block approach by reacting preformed Na6Ge2Se6 and MnCl2 at 750 °C. The structure consists of layers of [Na(1)Mn(Ge2Se6)]3– stacked perpendicular to the c-axis and sodium ions occupying the interlayer space. An indirect bandgap of 1.52 eV has been calculated using density functional theory, which is expectedly underestimated compared to the observed optical bandgap of 1.95 eV derived from diffuse reflectance spectroscopic measurements in the UV/Vis/NIR region. Magnetic measurements confirm the paramagnetic nature of Na8Mn2(Ge2Se6)2 with an experimental magnetic moment of 5.8 μB in good agreement with the theoretical spin …

Solving Electron Spin Drift-Diffusion Equations In Presence Of Hyperfine Interactions, Dana Coleman, Bryan Stevens, Truman Schulz

Undergraduate Research Competition

Next generation technologies have been proposed where electron spin is used in addition to electron charge in order to improve functionality and efficiency of electronic devices. In this work, we study how nuclear fields, magnetic fields from atomic nuclei, influence spin transport characteristics in semiconductors. Nuclear fields are added to the spin drift- diffusion equation and the resulting spin distributions are calculated. Due to the complicated nature of the nuclear field, the steady state spin drift-diffusion equations are non-linear and must be solved numerically. In this work, we examine solutions for the spin distribution and spin current in the presence …