Physical Sciences and Mathematics Commons^™

Growth Of Germanium Thin Films On Sapphire Using Molecular Beam Epitaxy, Emmanuel Wangila, Peter Lytvyn, Hryhorii Stanchu, Calbi Gunder, Fernando Maia De Oliveira, Samir Saha, Subhashis Das, Niroshi Eldose, Chen Li, Mohammad Zamani-Alavijeh, Mourad Benamara, Yuriy I. Mazur, Shui-Qing Yu, Gregory J. Salamo

Electrical Engineering Faculty Publications and Presentations

Germanium films were grown on c-plane sapphire with a 10 nm AlAs buffer layer using molecular beam epitaxy. The effects of Ge film thickness on the surface morphology and crystal structure were investigated using ex situ characterization techniques. The nucleation of Ge proceeds by forming (111) oriented three-dimensional islands with two rotational twin domains about the growth axis. The boundaries between the twin grains are the origin of the 0.2% strain and tilt grains. The transition to a single-grain orientation reduces the strain and results in a better-quality Ge buffer. Understanding the role of thickness on material quality during the …

Broadband Quantum Enhancement Of The Ligo Detectors With Frequency-Dependent Squeezing, D. Ganapathy, W. Jia, M. Nakano, V. Xu, N. Aritomi, T. Cullen, N. Kijbunchoo, S. E. Dwyer, Francisco Llamas, Volker Quetschke

Physics and Astronomy Faculty Publications and Presentations

Quantum noise imposes a fundamental limitation on the sensitivity of interferometric gravitational-wave detectors like LIGO, manifesting as shot noise and quantum radiation pressure noise. Here, we present the first realization of frequency-dependent squeezing in full-scale gravitational-wave detectors, resulting in the reduction of both shot noise and quantum radiation pressure noise, with broadband detector enhancement from tens of hertz to several kilohertz. In the LIGO Hanford detector, squeezing reduced the detector noise amplitude by a factor of 1.6 (4.0 dB) near 1 kHz; in the Livingston detector, the noise reduction was a factor of 1.9 (5.8 dB). These improvements directly impact …

A Simple, Isotropic Depolarized Light Source, Keith Foreman, T. J. Gay

Department of Physics and Astronomy: Faculty Publications

Unpolarized light can be an important tool in optical experiments. Producing it, however, can prove to be a challenge. Natural sources of light that are commonly thought of as unpolarized are, in fact, either weakly polarized or not practical sources of light in a laboratory setting. Standard, commercially available light depolarizers produce unpolarized light only after the polarization state of the light across the diameter of the output beam has been averaged. Locally, such beams are highly polarized. In this work, we report a simple, low cost light depolarizer capable of producing light with a total polarization of less than …

Modification Of Chitosan Using Glycidyl Methacrylate-Grafted Cellulose (Gmagcell/ Chi) For Methylene Blue Adsorption, Haya Fathana, Rahmi Rahmi, Muhammad Adlim, Surya Lubis

Karbala International Journal of Modern Science

In this study, a glycidyl methacrylate-grafted cellulose/chitosan (GMA-g-Cell/Chi) film was successfully prepared and characterized. GMA-g-Cell was obtained from the grafting process of cellulose derived from sugarcane bagasse using glycidyl methacrylate (GMA). The cellulose grafting process was obtained using 20% GMA for 4 hours at 60oC. The percentage of grafting (PG) and grafting efficiency (GE) values for these parameters were 516 and 60.28%, respectively. Chitosan was modified with GMA-g-Cell and has higher adsorption capacity and tensile strength than chitosan. The adsorption kinetics tend to follow the pseudo-first-order adsorption kinetics model, with Qe and k1 being 7 mg/g and 0.067 g/mg. minute. …

Seeing The Invisible: Projects On Flow Imaging From The Fluid Mechanics Lab, Keith Stein

Day of Scholarship

Shadowgraph and schlieren imaging are popular flow visualization techniques because, despite the straightforward setup and reliance on very simple geometrical optics principles, they provide powerful methods for capturing high-quality images of what would otherwise be invisible flow phenomena. Application of these methods along with high-speed video recording can reveal detailed pictures of fast flow events that may last for just a fraction of a millisecond. These techniques are being utilized in the Bethel Fluid Mechanics lab course (PHY423/ENR423) and in a number of student-faculty research projects. We present snapshots of a few recent student-faculty projects utilizing shadowgraph and schlieren imaging.

Search For Pair Production Of Vector-Like Quarks In Cms Run 2 Data, Julie Hogan

Day of Scholarship

The Compact Muon Solenoid experiment (CMS) at the CERN Large Hadron Collider records proton-proton collision data in order to study the particles and forces that exist in very high energy conditions. The 2012 discovery of the Higgs boson was a triumph for the field of particle physics, but pointed toward the probably existence of unknown high-mass particles. Vector-like quarks (VLQs) are a possible type of high-mass fermions, and their decays to lighter particles create exciting detector signatures. This search utilizes deep machine learning to both identify decay products of VLQs in the detector and to separate potential signal events from …

Particle Discovery Lab For Education & Outreach, Julie Hogan

Day of Scholarship

The Compact Muon Solenoid experiment (CMS) at the CERN Large Hadron Collider records proton-proton collision data in order to study the particles and forces that exist in very high energy conditions. CMS releases data to the public after several years of internal analysis. This data has a rich history of use for middle school or high school education, but is not widely used by college students in the US. Bethel students and I have built an intermediate-level undergraduate lab experience in which students reinforce physics learning objectives and learn statistical data analysis skills while "discovering" a particle. A short form …

Nano-Optics: Light, Matter, And Single-Molecule Imaging, Nathan Lindquist

Day of Scholarship

Light and matter interact in fascinating ways at the nano-scale, allowing scientists to image, probe, analyze, or manipulate single molecules. This interdisciplinary field has opened the doors to a vast array of insights and applications, including single-molecule sensors, advanced photonic devices, and novel forms of microscopy. This poster summarizes work done at Bethel over the past few years in the areas of nano-imaging, nano-sensing, and nano-manipulation.

Creation And Development Of A Next Generation Simulation Model For Spacecraft Charging, Brian P. Beecken

Day of Scholarship

Spacecraft, particularly satellites, endure the bombardment of high-energy electrons. These electrons charge up the insulators on the spacecraft. Eventually, the charge commonaly can exceed 100,000 volts. The result is an electrostatic discharge which will potentially cripple the spacecraft. A computer simulation model has been developed that will predict if and when the discharge will occur.

A New Algorithm For Determining Energy And Charge Deposition In Spacecraft Insulators, Brian P. Beecken

Day of Scholarship

Space if filled with highly energetic electrons, many of which originate from the sun. All earth satellites must have insulators. Unfortunately, the insulators absorb both the electrons and the energy that they are carrying. Once sufficient charge accumulates, it is released in a sudden and destructive pulse which can destroy the onboard electronics and solar panel. The depth of penetration of the electrons in the insulators varies with incident energy, flux, and material. Determining the deposition profiles is key to understanding and mitigating the threat to satellites.

Understanding The Nature Of Pulsars And Characterizing Propagation Effects Using Pulsar Timing, Pratik Kumar

Physics & Astronomy ETDs

Pulsars are highly magnetized stellar remnants, among the densest known objects, and primarily produce radio emission in the form of lighthouse beams sweeping across the line of sight as a regular train of pulses. Apart from providing tests for matter in high-density regimes, general relativity, and plasma emission; perhaps the most notable characteristic is their applicability as precise astronomical clocks to measure various effects. Pulsar Timing Arrays (PTAs) are galactic scale detectors analogous to ground-based detectors of Gravitational Waves (GWs) like LIGO, with the aim of detecting low-frequency nano-Hz GWs from coalescing binary supermassive black holes. PTAs consist of a …

Breakdown Of The Drift-Diffusion Model For Transverse Spin Transport In A Disordered Pt Film, Kirill D. Belashchenko, Giovanni G. Baez Flores, Wuzhang Fang, Alexey Kovalev, Mark Van Schilfgaarde, Paul M. Haney, Mark D. Stiles

Department of Physics and Astronomy: Faculty Publications

Spin-accumulation and spin-current profiles are calculated for a disordered Pt film subjected to an in-plane electric current within the nonequilibrium Green's function approach. In the bulklike region of the sample, this approach captures the intrinsic spin Hall effect found in other calculations. Near the surfaces, the results reveal qualitative differences with the results of the widely used spin-diffusion model, even when the boundary conditions are modified to try to account for them. One difference is that the effective spin-diffusion length for transverse spin transport is significantly different from its longitudinal counterpart and is instead similar to the mean-free path. This …

Majorana Bound States In A D-Wave Superconductor Planar Josephson Junction, Hamed Vakili, Moaz Ali, Mohamed Elekhtiar, Alexey Kovalev

Department of Physics and Astronomy: Faculty Publications

We study phase-controlled planar Josephson junctions comprising a two-dimensional electron gas with strong spin-orbit coupling and d-wave superconductors, which have an advantage of a high critical temperature. We show that a region between the two superconductors can be tuned into a topological state by the in-plane Zeeman field, and can host Majorana bound states. The phase diagram as a function of the Zeeman field, chemical potential, and the phase difference between superconductors exhibits the appearance of Majorana bound states for a wide range of parameters. We further investigate the behavior of the topological gap and its dependence on the …

Directional Microwave Emission From Femtosecond-Laser Illuminated Linear Arrays Of Superconducting Rings, Thomas J. Bullard, Kyle Frische, Charlie Ebbing, Stephen J. Hageman, John Morrison, John Bulmer, Enam A. Chowdury, Michael L. Dexter, Timothy J. Haugan, Anil K. Patniak

Faculty Publications

We examine the electromagnetic emission from two photo-illuminated linear arrays composed of inductively charged superconducting ring elements. The arrays are illuminated by an ultrafast infrared laser that triggers microwave broadband emission detected in the 1–26 GHz range. Based on constructive interference from the arrays a narrowing of the forward radiation lobe is observed with increasing element count and frequency demonstrating directed GHz emission. Results suggest that higher frequencies and a larger number of elements are achievable leading to a unique pulsed array emitter concept that can span frequencies from the microwave to the terahertz (THz) regime.

Active-Illumination Extension To The Priest And Meier Pbrdf, Mark F. Spencer, Milo W. Hyde Iv, Santasri R. Bose-Pillai, Michael A. Marciniak

Faculty Publications

This paper develops a 3D vector solution for the scattering of partially coherent laser-beam illumination from statistically rough surfaces. Such a solution enables a rigorous comparison to the well-known Priest and Meier polarimetric bidirectional reflectance distribution function (pBRDF) [Opt Eng 41(5),988 (2002).]. Overall, the comparison shows excellent agreement for the normalized spectral density and the degree of polarization. Based on this agreement, the 3D vector solution also enables an extension to the Priest and Meier pBRDF that accounts for the effects of active illumination. In particular, the 3D vector solution enables the development of a closed-form expression for the spectral …

Using Dna Flow-Stretching Assay As A Tool To Validate The Tagging Of Dna-Binding Proteins For Single-Molecule Experiments, Miranda Molina, Lindsey E. Way, Zhongqing Ren, Qin Liao, Bianca Guerra, Brandon Shields, Xindan Wang, Hyeongjun Kim

Physics and Astronomy Faculty Publications and Presentations

Highlights

• KCK tag can alter protein properties both quantitatively and qualitatively

• Electrostatic interactions between the KCK tag and DNA contribute to the artifacts

• Adding a short peptide tag to ParB protein does not lead to its in vivo changes

• Single-molecule DNA flow-stretching assay can detect protein property changes

Motivation

Single-molecule fluorescence microscopy has been extensively used in modern biology to define the molecular action of proteins. Appending short peptide tags is a common strategy to enhance fluorescence labeling. Here, we evaluate the impact of a commonly used tag, the lysine-cysteine-lysine (KCK) tag, on protein behavior in single-molecule DNA flow-stretching assay, …

A Framework To Validate Fluorescently Labeled Dna-Binding Proteins For Single-Molecule Experiments, Miranda L. Molina, Lindsey E. Way, Zhongqing Ren, Qin Liao, Bianca Guerra, Brandon Shields, Xindan Wang, Hyeongjun Kim

Physics and Astronomy Faculty Publications and Presentations

Due to the enhanced labeling capability of maleimide-based fluorescent probes, lysine-cysteine-lysine (KCK) tags are frequently added to proteins for visualization. In this study, we employed an in vitro single-molecule DNA flow-stretching assay as a sensitive way to assess the impact of the KCK tag on the property of DNA-binding proteins. Using Bacillus subtilis ParB as an example, we show that, although no noticeable changes were detected by in vivo fluorescence imaging and chromatin immunoprecipitation (ChIP) assays, the KCK tag substantially altered ParB's DNA compaction rates and its response to nucleotide binding and to the presence of the specific sequence (parS) …

The High Pressure Dependence Of X-Ray Induced Decomposition Of Cadmium Oxalate, Adrian F. Lua Sanchez, Petrika Cifligu, Marc Graff, Michael Pravica, Pradip K. Bhowmik, Changyong Park, Egor Evlyukhin

Physics & Astronomy Faculty Research

The high proclivity of x rays to destabilize and distort molecular structures has been previously utilized in the synthesis of novel compounds. Here, we show that x-ray induced decomposition of cadmium oxalate induces chemical and structural transformations only at 0.5 and 1 GPa. Using x-ray diffraction and Raman spectroscopy, the synthesized product is identified as cadmium carbonate with cadmium oxalate remnants, which is stable under ambient conditions. At ambient and >1 GPa pressures, only degradation of the electronic density distribution is observed. The transformation kinetics are examined in terms of Avrami’s model, which demonstrates that despite the necessity of high …

Entanglements Of Teenage Food Security Within High School Pantries In Pinellas County, Florida, Karen T. Díaz Serrano

USF Tampa Graduate Theses and Dissertations

Food insecurity has the ability to shape an individual’s or a family’s everyday life and take emotional, psychological, and physical tolls. Among adolescents, not having access to nutritious food could lead to physical effects during growth and development. Moreover, the stress and anxiety of not knowing where their next meal is coming from and the social stigma associated with being food insecure can have negative effects on mental health. A recent solution to these issues is locating food pantries in high schools. Purpose: This exploratory study examined how high school students in Pinellas County, Florida perceive the use of a …

A Model For The Multi-Virus Contact Process, Xu Huang

Rose-Hulman Undergraduate Mathematics Journal

We study one specific version of the contact process on a graph. Here, we allow multiple infections carried by the nodes and include a probability of removing nodes in a graph. The removal probability is purely determined by the number of infections the node carries at the moment when it gets another infection. In this paper, we show that on any finite graph, any positive value of infection rate $\lambda$ will result in the death of the process almost surely. In the case of $d$-regular infinite trees, We also give a lower bound on the infection rate in order for …

Biosynthesis Of Mgo Nanoparticles And Their Impact On The Properties Of The Pva/Gelatin Nanocomposites For Smart Food Packaging Applications, Mohamed Morsy

Nanotechnology Research Centre

No abstract provided.

Fast-Askap Synergy: Quantifying Coexistent Tidal And Ram Pressure Strippings In The Ngc 4636 Group, Xuchen Lin, Jing Wang, Virginia Kilborn, Eric W. Peng, Luca Cortese, Alessandro Boselli, Ze-Zhong Liang, Bumhyun Lee, Dong Yang, Juan P. Madrid

Physics and Astronomy Faculty Publications and Presentations

Combining new H I data from a synergetic survey of Australian Square Kilometre Array Pathfinder (ASKAP) Widefield ASKAP L-band Legacy All-sky Blind surveY and Five-hundred-meter Aperture Spherical radio Telescope with the Arecibo Legacy Fast ALFA data, we study the effect of ram pressure and tidal interactions in the NGC 4636 group. We develop two parameters to quantify and disentangle these two effects on gas stripping in H I-bearing galaxies: the strength of external forces at the optical-disk edge, and the outside-in extents of H I-disk stripping. We find that gas stripping is widespread in this group, affecting 80% of H …

Homonuclear Ultracold Elastic S-Wave Collisions Of Alkali-Metal Atoms Via Multichannel Quantum Defect Theory, Alyson T. Laskowski, Nirav P. Mehta

Physics and Astronomy Faculty Research

Multichannel quantum-defect theory (MQDT) provides a powerful toolkit for describing and understanding collisions of cold alkali-metal atoms. Various MQDT approximations differ primarily in how they characterize the so-called short-ranged K matrix K_sr, which encapsulates the short-ranged physics into a handful of low-energy parameters that exhibit simple and smooth dependence on energy and field. Here, we compare three different methods for computing K_sr for homonuclear collisions of alkali-metal atoms, from lithium to cesium. The MQDT calculations are benchmarked against numerically converged coupled-channels calculations that use a log-derivative propagator out to the asymptotic region. We study how well these …

Whittle, Charles Edward, Jr., 1931-2012 (Sc 3698), Manuscripts & Folklife Archives

Manuscript Collection Finding Aids

Finding aid only for Manuscripts Small Collection 3698. Well-illustrated biographical volume on the life, career and family of Charles E. Whittle, Jr., a Brownsville, Kentucky native who served as a physics professor at Western Kentucky University and at Centre College, and as a senior scientist at Oak Ridge Associated Universities, Oak Ridge, Tennessee.

Enhancement Of Er Luminescence From Bridge-Type Photonic Crystal Nanocavities With Er, O-Co-Doped Gaas, Zhidong Fang, Jun Tatebayashi, Ryohei Homi, Masayuki Ogawa, Hirotake Kajii, Masahiko Kondow, Kyoko Kitamura, Brandon Mitchell, Shuhei Ichikawa, Yasufumi Fujiwara

Physics & Engineering Faculty Publications

A bridge-type photonic crystal (PhC) nanocavity based on Er,O-codoped GaAs is employed to realize enhancement of Er luminescence. By adjusting the structural design and measurement temperature, the cavity mode's wavelength can be coupled to Er luminescence. The peak emission intensity from an Er-2O defect center was enhanced 7.3 times at 40 nW pump power and 77 K. The experimental Q-factor is estimated to be over 1.2 x 104, and the luminescence intensity shows superlinearity with excitation power, suggesting Er luminescence amplification. This result would pave the way towards the realization of highly efficient single-photon emitters based on rare-earth elements.

Fortifying Iot Against Crimpling Cyber-Attacks: A Systematic Review, Usman Tariq, Irfan Ahmed, Muhammad Attique Khan, Ali Kashif Bashir

Karbala International Journal of Modern Science

The rapid growth and increasing demand for Internet of Things (IoT) devices in our everyday lives create exciting opportunities for human involvement, data integration, and seamless automation. This fully interconnected ecosystem considerably impacts crucial aspects of our lives, such as transportation, healthcare, energy management, and urban infrastructure. However, alongside the immense benefits, the widespread adoption of IoT also brings a complex web of security threats that can influence society, policy, and infrastructure conditions. IoT devices are particularly vulnerable to security violations, and industrial routines face potentially damaging vulnerabilities. To ensure a trustworthy and robust security framework, it is crucial to …

New Quantum Genetic Algorithm Based On Constrained Quantum Optimization, Mohammed R. Almasaoodi, Abdulbasit M. A. Sabaawi, Sara El Gaily, Sándor Imre

Karbala International Journal of Modern Science

In the past decades, many quantum algorithms have been developed. The main obstacle that prevents the widespread implementation of these algorithms is the small size of the available quantum computer in terms of qubits. Blind Quantum Computation (BQC) holds the promise of handling this issue by delegating computation to quantum remote devices. Here, we introduce a novel Constrained Quantum Genetic Algorithm (CQGA) that selects the optimum extreme (minimum or maximum) value of a constrained goal function (or a vast unsorted database) with very low computational complexity. Since the convergence speed to the optimal solution for the Constrained Classical Genetic Algorithm …

Observation Of Τ Lepton Pair Production In Ultraperipheral Pb-Pb Collisions At √SNn=5.02 Tev, A. Tumasyan

Department of Physics and Astronomy: Faculty Publications

We present an observation of photon-photon production of τ lepton pairs in ultraperipheral lead-lead collisions. The measurement is based on a data sample with an integrated luminosity of 404 μb⁻¹ collected by the CMS experiment at a center-of-mass energy per nucleon pair of √s_NN = 5.02 TeV. The γγ → τ⁺τ⁻ process is observed for τ⁺τ⁻ events with a muon and three charged hadrons in the final state. The measured fiducial cross section is σ(γγ → τ⁺τ^-) = 4.8 ± 0.6(stat) ± 0.5(syst) μb, where the second …

On The Origins Of Life — Modelling The Initial Stages Of Complex Coacervate Droplet Formation, Yixuan Wu

Western Libraries Undergraduate Research Awards (WLURAs)

Coacervate droplets are considered a plausible model for protocells due to their spontaneous formation and ability to compartmentalize macromolecules such as nucleic acid and peptides. Although experimental studies have observed and synthesized coacervates under different laboratory conditions, little is known about their structure. Here we present atomistic molecular dynamic simulations of the interactions between water and oppositely charged proteins that cluster together in a salt-dependent process. Observing such liquid-liquid phase separation on an atomic level would serve as a model for the initial stages of complex coacervate formation. Molecular Dynamics was used to compute diagnostics of the structure at different …

Recent Advances In Crispr/Cas9-Assisted Gene Therapy, Apeksha Srivastava, Shikha Chauhan, Vishal Ahuja

Karbala International Journal of Modern Science

CRISPR/Cas9 (Clustered regularly interspaced short palindromic repeats) is an exponentially growing tool with wide-spread applications in therapeutics like gene modifications that focus on altering the hereditary material to repair or eliminate any defective gene-causing diseases like cancer, AIDS (Acquired immunodeficiency syndrome), etc. It also includes the identification of the target sequence with the help of sgRNA followed by the substitution of a malfunction-ing gene with a normal version. It offers high efficiency, specificity, and post-gene-editing efficacy, but have also some off-target impressions, and immunogenic effects. The contribution of CRISPR/Cas9 has already been proved primarily in in-vitro studies using animal germ …