Digital Commons Network^™

Experimental Verification Of Principal Losses In A Regulatory Particulate Matter Emissions Sampling System For Aircraft Turbine Engines, D. B. Kittelson, J. Swanson, M. Aldridge, R. A. Giannelli, J. S. Kinsey, J. A. Stevens, D. S. Liscinsky, Donald E. Hagen, For Full List Of Authors, See Publisher's Website.

Physics Faculty Research & Creative Works

A sampling system for measuring emissions of nonvolatile particulate matter (nvPM) from aircraft gas turbine engines has been developed to replace the use of smoke number and is used for international regulatory purposes. This sampling system can be up to 35 m in length. The sampling system length in addition to the volatile particle remover (VPR) and other sampling system components lead to substantial particle losses, which are a function of the particle size distribution, ranging from 50 to 90% for particle number concentrations and 10-50% for particle mass concentrations. The particle size distribution is dependent on engine technology, operating …

Gravitational Wave Sensors Based On Superconducting Transducers, Armen Gulian, Joe Foreman, Vahan Nikoghosyan, Louis Sica, Pablo Abramian-Barco, Jeff Tollaksen, Gurgen Melkonyan, Iris Mowgood, Chris Burdette, Rajendra Dulal, Serafim Teknowijoyo, Sara Chahid, Shmuel Nussinov

Mathematics, Physics, and Computer Science Faculty Articles and Research

Following the initial success of LIGO, new advances in gravitational wave (GW) detector systems are planned to reach fruition during the next decades. These systems are interferometric and large. Here we suggest different, more compact detectors of GW radiation with competitive sensitivity. These nonresonant detectors are not interferometric. They use superconducting Cooper pairs in a magnetic field to transform mechanical motion induced by GW into detectable magnetic flux. The detectors can be oriented relative to the source of GW, so as to maximize the signal output and help determine the direction of nontransient sources. In this design an incident GW …

Optically Active Selenium Vacancies In Baga4Se7 Crystals, Brian C. Holloway, Timothy D. Gustafson, Christopher A. Lenyk, Nancy C. Giles, Kevin T. Zawilski, Peter G. Schunemann, Kent L. Averett, Larry E. Halliburton

Faculty Publications

Barium gallium selenide (BaGa₄Se₇) is a recently developed nonlinear optical material with a transmission window extending from 470 nm to 17 μm. A primary application of these crystals is the production of tunable mid-infrared laser beams via optical parametric oscillation. Unintentional point defects, such as selenium vacancies, cation vacancies (barium and/or gallium), and trace amounts of transition-metal ions, are present in BaGa₄Se₇ crystals and may adversely affect device performance. Electron paramagnetic resonance (EPR) and optical absorption are used to identify and characterize these defects. Five distinct EPR spectra, each representing an electron …

Interface-Induced Lattice Structure And Magnetism In Ultrathin Transition Metal Oxide Trilayers, David Howe

LSU Doctoral Dissertations

The study of magnetism has been a rich playground in condensed matter physics due to the multiple mechanisms capable of producing the effect and its relationship to multiple characteristics of a material. Transition metal oxides (TMOs) have been of particular interest for ongoing research into magnetic phenomenon due to the abundance of interesting physical phenomena found in member systems such as colossal magnetoresistance, skyrmion formation, and interface-driven 2D electron gases. Thin films introduce an additional thickness-dependent element, where reduction below a critical thickness eliminates the magnetic coherence of a system and FM order is lost. The atomic structure of these …

Hα Reverberation Mapping Of The Intermediate-Mass Active Galactic Nucleus In Ngc 4395, Hojin Cho, Jong-Hak Woo, Tommaso Treu, Peter R. Williams, Stephen F. Armen, Aaron J. Barth, Vardha N. Bennert, Wanjin Cho, Alexei V. Filippenko, Elena Gallo, Jaehyuk Geum, Diego González-Buitrago, Kayhan Gültekin, Edmund Hodges-Kluck, John C. Horst, Seong Hyeon Hwang, Wonseok Kang, Minjin Kim, Taewoo Kim, Douglas C. Leonard, Matthew A. Malkan, Raymond P. Remigio, David J. Sand, Jaejin Shin, Donghoon Son, Hyun-Il Sung, Vivian U

Physics

We present the results of a high-cadence spectroscopic and imaging monitoring campaign of the active galactic nucleus (AGN) of NGC 4395. High signal-to-noise-ratio spectra were obtained at the Gemini-N 8 m telescope using the GMOS integral field spectrograph (IFS) on 2019 March 7 and at the Keck I 10 m telescope using the Low-Resolution Imaging Spectrometer with slit masks on 2019 March 3 and April 2. Photometric data were obtained with a number of 1 m-class telescopes during the same nights. The narrow-line region (NLR) is spatially resolved; therefore, its variable contributions to the slit spectra make the standard procedure …

Magnetic Dichroism In Few-Photon Ionization Of Polarized Atoms, B. P. Acharya, M. Dodson, S. Dubey, K. L. Romans, A. H.N.C. De Silva, K. Foster, O. Russ, K. Bartschat, N. Douguet, Daniel Fischer

Physics Faculty Research & Creative Works

We consider few-photon ionization of atomic lithium by linearly polarized femtosecond laser pulses and demonstrate that asymmetries of the electron angular distribution can occur for initially polarized (2p, m=+1) target atoms. The dependence of the photoelectron emission angle relative to the electric field direction is investigated at different laser intensities and wavelengths. The experimental spectra show excellent agreement with numerical solutions of the time-dependent Schrödinger equation. In the perturbative picture, the angular shift is traced back to interferences between partial waves with mean magnetic quantum number (m)≠0. This observation allows us to obtain quantum mechanical information on the final electronic …

Proving The Possibility Of The Calculation Of The Madeluag Constant For The Sodium Chloride Crystal Using A Limited Number Of The Terms Of The Series Giving The Expression Of This Constant, Saleh Saeed Barbaid

Hadhramout University Journal of Natural & Applied Sciences

In this research, after referring to the basic assumption of the theory of the binding energy of the ionic crystals, we explained the Madelung constant and then, we show how the method of the neutral electric groups introduced by Evjen facilitates the convergent of the series showing the Madelung constant. Then, afterwards, we reviewed the principal points of the crystalline structure of the sodium chloride which crystallizes in a cubic faces centred lattice; showing that the apparition 0f 27 ions in each unit cell of its space lattice; afterward we calculate different values of the Madelung constant, showing how we …

Theory Of Change, Center For Complexity

Horizon 2045

Horizon 2045 (H2045) is a 25-year initiative to end the nuclear weapons century.

We urgently need to manage the intertwined existential risks of the Anthropocene—the geological era that began with the 1945 Trinity Test and is characterized by humankind’s newfound capacity to destroy itself along with all life on the planet.

Recent research has shown that concerns about existential threats have become palpable, as has the desire to solve human-made problems and move to a brighter future. This offers an important opportunity: By considering nuclear weapons in the context of other dangers, we can dismantle conventional wisdom that nuclear weapons …

Carbon Nano Based Materials And Their Composites For Gas Sensing Applications: Review, Mohamed Morsy

Nanotechnology Research Centre

No abstract provided.

Ultrasound Regulated Flexible Protein Materials: Fabrication, Structure And Physical-Biological Properties., Bowen Cai, Hanling Gu, Fang Wang, Kyle Printon, Zhenggui Gu, Xiao Hu

College of Science & Mathematics Departmental Research

Ultrasound can be used in the biomaterial field due to its high efficiency, easy operation, no chemical treatment, repeatability and high level of control. In this work, we demonstrated that ultrasound is able to quickly regulate protein structure at the solution assembly stage to obtain the designed properties of protein-based materials. Silk fibroin proteins dissolved in a formic acid-CaCl solution system were treated in an ultrasound with varying times and powers. By altering these variables, the silks physical properties and structures can be fine-tuned and the results were investigated with Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron …

Comparison Of Charge Deposition Profiles In Polymers Irradiated With Monoenergetic Electrons: Pulsed Electroacoustic Measurements And Af-Numit3 Modeling, Zachary Gibson, Jr Dennison, Brian Beecken

Physics Student Research

Successful spacecraft design and charging mitigation techniques require precise and accurate knowledge of charge deposition profiles. This paper compares models of charge deposition and transport using a venerable deep dielectric charging code, AF-NUMIT3, with direct measurements of charge profiles via pulsed electroacoustic (PEA) measurements. Eight different simulations were performed for comparison to PEA experiments of samples irradiated by 50 keV or 80 keV monoenergetic electrons in vacuum and at room temperature. Two materials, polyether-ether ketone (PEEK) and polytetrafluoroethylene (PTFE), were chosen for their very low conductivities so that minimal charge migration would occur between irradiation and PEA measurements. PEEK was …

The Ionic Selectivity Of Lysenin Channels In Open And Sub-Conducting States, Andrew Bogard, Pangaea W. Finn, Fulton Mckinney, Ilinca M. Flacau, Aviana R. Smith, Rosey Whiting, Daniel Fologea

Physics Faculty Publications and Presentations

The electrochemical gradients established across cell membranes are paramount for the execution of biological functions. Besides ion channels, other transporters, such as exogenous pore-forming toxins, may present ionic selectivity upon reconstitution in natural and artificial lipid membranes and contribute to the electrochemical gradients. In this context, we utilized electrophysiology approaches to assess the ionic selectivity of the pore-forming toxin lysenin reconstituted in planar bilayer lipid membranes. The membrane voltages were determined from the reversal potentials recorded upon channel exposure to asymmetrical ionic conditions, and the permeability ratios were calculated from the fit with the Goldman–Hodgkin–Katz equation. Our work shows that …

All-Sky Search For Short Gravitational-Wave Bursts In The Third Advanced Ligo And Advanced Virgo Run, R. Abbott, T. D. Abbott, F. Acernese, K. Ackley, Teviet Creighton, Mario C. Diaz, Francisco Llamas, Soma Mukherjee, Volker Quetschke, Wen Hui Wang

Physics & Astronomy Faculty Publications

This paper presents the results of a search for generic short-duration gravitational-wave transients in data from the third observing run of Advanced LIGO and Advanced Virgo. Transients with durations of milliseconds to a few seconds in the 24–4096 Hz frequency band are targeted by the search, with no assumptions made regarding the incoming signal direction, polarization, or morphology. Gravitational waves from compact binary coalescences that have been identified by other targeted analyses are detected, but no statistically significant evidence for other gravitational wave bursts is found. Sensitivities to a variety of signals are presented. These include updated upper limits on …

Uncertainty Analysis For Ccd-Augmented Casi® Brdf Measurement System, Todd V. Small, Samuel D. Butler, Michael A. Marciniak

Faculty Publications

This work presents a measurement uncertainty analysis for a system designed to simultaneously capture specular in-plane and out-of-plane bidirectional reflectance distribution function (BRDF) data with high spatial resolution by augmenting the Complete Angle Scatter Instrument (CASI®) with a charge-coupled device (CCD) camera. Various scatter flux, incident flux, scatter angle, and detector solid angle uncertainty contributions are considered and evaluated based on imperfectly known system parameters. In particular, incident flux temporal fluctuation, detector noise and non-linearity, and out-of-plane aperture misalignment considerations each require significant adjustment from original CASI® uncertainty analysis, and expressions for neutral density (ND) filter, scatter angle, and solid …

Spatiotemporal Non-Uniformly Correlated Beams, Milo W. Hyde Iv

Faculty Publications

We present a new partially coherent source with spatiotemporal coupling. The stochastic light, which we call a spatiotemporal (ST) non-uniformly correlated (NUC) beam, combines space and time in an inhomogeneous (shift- or space-variant) correlation function. This results in a source that self-focuses at a controllable location in space-time, making these beams potentially useful in applications such as optical trapping, optical tweezing, and particle manipulation. We begin by developing the mutual coherence function for an ST NUC beam. We then examine its free-space propagation characteristics by deriving an expression for the mean intensity at any plane z ≥ 0. To validate …

College Of Natural Sciences Scholarship Brunch Program, November 6th 2021, College Of Natural Sciences

College of Natural Sciences Newsletters and Reports

This is the program for the first annual College of Natural Sciences Scholarship Brunch, held on November 6th, 2021 at McCrory Gardens.

College Of Natural Sciences Newsletter, November 2021, College Of Natural Sciences

College of Natural Sciences Newsletters and Reports

Volume 2, Issue 11

Page 1 Dean's Message
Page 2 Awards & Recognition
Page 3 Media Coverage of CNS
Page 4 2021 Day of Scholars
Page 5 Astronomy Outreach
Page 6 SDSU Faculty & Students Host American Society for Microbiology Annual Conference
Page 7 Scholarship Brunch
Page 8 Open PRAIRIE Data, SI Final Exam Review Sessions
Page 9 Aamlid Family Anatomy Lab Photos

Examination Of The Catalytic Role Of The Axial Cystine Ligand In The Co-Type Nitrile Hydratase From Pseudonocardia Thermophila Jcm 3095, Irene Anyango Ogutu, Martin St. Maurice, Brian Bennett, Richard C. Holz

Physics Faculty Research and Publications

The strictly conserved αSer162 residue in the Co-type nitrile hydratase from Pseudonocardia thermophila JCM 3095 (PtNHase), which forms a hydrogen bond to the axial αCys108-S atom, was mutated into an Ala residue. The αSer162Ala yielded two different protein species: one was the apoform (αSer^A) that exhibited no observable activity, and the second (αSer^B) contained its full complement of cobalt ions and was active with a k_cat value of 63 ± 3 s⁻¹ towards acrylonitrile at pH 7.5. The X-ray crystal structure of was determined at 1.85 Å resolution and contained no detectable …

Identification Of An Intermediate Species Along The Nitrile Hydratase Reaction Pathway By Epr Spectroscopy, Wasantha Lankathilaka Karunagala Pathiranage, Natalie Gumataotao, Adam T. Fiedler, Richard C. Holz, Brian Bennett

Physics Faculty Research and Publications

A new method to trap catalytic intermediate species was employed with Fe-type nitrile hydratase from Rhodococcus equi TG328-2 (ReNHase). ReNHase was incubated with substrates in a 23% (w/w) NaCl/H₂O eutectic system that remained liquid at −20 °C, thereby permitting the observation of transient species that were present at electron paramagnetic resonance (EPR)-detectable levels in samples frozen while in the steady state. Fe^III-EPR signals from the resting enzyme were unaffected by the presence of 23% NaCl, and the catalytic activity was ∼55% that in the absence of NaCl at the optimum pH of 7.5. …

Acoustic/Gravity Wave Phenomena In Wide-Field Imaging: From Data Analysis To A Modeling Framework For Observability In The Mlt Region And Beyond, Jaime Aguilar Guerrero

Doctoral Dissertations and Master's Theses

Acoustic waves, gravity waves, and larger-scale tidal and planetary waves are significant drivers of the atmosphere’s dynamics and of the local and global circulation that have direct and indirect impacts on our weather and climate. Their measurements and characterization are fundamental challenges in Aeronomy that require a wide range of instrumentation with distinct operational principles. Most measurements share the common features of integrating optical emissions or effects on radio waves through deep layers of the atmosphere. The geometry of these integrations create line-of-sight effects that must be understood, described, and accounted for to properly present the measured data in traditional …

Development Of A Methodology For Data Integration Of Multiple Datasets In The Study Of Martian Dust Storms, Rawdha Majid Al Bedwawi

Theses

The research investigates the distribution of dust on mars. In general, the study is inspired by the need to provide findings that will improve the study about extraterrestrial phenomena. The research explains the practical effects of extraterrestrial physics considering it entails assessing the extraterrestrial matter. The research seeks to validate the correctness of multiannual data pretending to the pertaining to the optical depth of optical depth of column dust, which would assist in determining the necessity of evaluating the existing map reconstruction approaches. the methodological section has several steps which combined qualitative and quantities optical depth and virtual imagery to …

Correcting Correlation Functions For Redshift-Dependent Interloper Contamination, Daniel J. Farrow, Ariel G. Sánchez, Robin Ciardullo, Shun Saito, For Full List Of Authors, See Publisher's Website.

Physics Faculty Research & Creative Works

The construction of catalogues of a particular type of galaxy can be complicated by interlopers contaminating the sample. In spectroscopic galaxy surveys this can be due to the misclassification of an emission line; for example in the Hobby-Eberly Telescope Dark Energy Experiment (HETDEX) low-redshift [O ii] emitters may make up a few per cent of the observed Ly α emitter (LAE) sample. The presence of contaminants affects the measured correlation functions and power spectra. Previous attempts to deal with this using the cross-correlation function have assumed sources at a fixed redshift, or not modelled evolution within the adopted redshift bins. …

Searches For Continuous Gravitational Waves From Young Supernova Remnants In The Early Third Observing Run Of Advanced Ligo And Virgo, R. Abbott, T. D. Abbott, S. Abraham, Teviet Creighton, Mario C. Diaz, Soma Mukherjee, Volker Quetschke, Karla E. Ramirez, Wenhui Wang

Physics & Astronomy Faculty Publications

We present results of three wide-band directed searches for continuous gravitational waves from 15 young supernova remnants in the first half of the third Advanced LIGO and Virgo observing run. We use three search pipelines with distinct signal models and methods of identifying noise artifacts. Without ephemerides of these sources, the searches are conducted over a fRequency band spanning from 10 to 2 kHz. We find no evidence of continuous gravitational radiation from these sources. We set upper limits on the intrinsic signal strain at 95% confidence level in sample subbands, estimate the sensitivity in the full band, and derive …

Constraints From Ligo O3 Data On Gravitational-Wave Emission Due To R-Modes In The Glitching Pulsar Psr J0537–6910, R. Abbott, T. D. Abbott, S. Abraham, F. Acernese, K. Ackley, Teviet Creighton, Mario C. Diaz, Soma Mukherjee, Volker Quetschke, Karla E. Ramirez, Wenhui Wang

Physics & Astronomy Faculty Publications

We present a search for continuous gravitational-wave emission due to r-modes in the pulsar PSR J0537-6910 using data from the LIGO-Virgo Collaboration observing run O3. PSR J0537-6910 is a young energetic X-ray pulsar and is the most frequent glitcher known. The inter-glitch braking index of the pulsar suggests that gravitational-wave emission due to r-mode oscillations may play an important role in the spin evolution of this pulsar. Theoretical models confirm this possibility and predict emission at a level that can be probed by ground-based detectors. In order to explore this scenario, we search for r-mode emission in the epochs between …

Technique To Solve Linear Fractional Differential Equations Using B-Polynomials Bases, Muhammad I. Bhatti, Md. Habibur Rahman

Physics & Astronomy Faculty Publications

A multidimensional, modified, fractional-order B-polys technique was implemented for finding solutions of linear fractional-order partial differential equations. To calculate the results of the linear Fractional Partial Differential Equations (FPDE), the sum of the product of fractional B-polys and the coefficients was employed. Moreover, minimization of error in the coefficients was found by employing the Galerkin method. Before the Galerkin method was applied, the linear FPDE was transformed into an operational matrix equation that was inverted to provide the values of the unknown coefficients in the approximate solution. A valid multidimensional solution was determined when an appropriate number of basis sets …

Resampling And Super-Resolution Of Hexagonally Sampled Images Using Deep Learning, Dylan Flaute, Russell C. Hardie, Hamed Elwarfalli

Electrical and Computer Engineering Faculty Publications

Super-resolution (SR) aims to increase the resolution of imagery. Applications include security, medical imaging, and object recognition. We propose a deep learning-based SR system that takes a hexagonally sampled low-resolution image as an input and generates a rectangularly sampled SR image as an output. For training and testing, we use a realistic observation model that includes optical degradation from diffraction and sensor degradation from detector integration. Our SR approach first uses non-uniform interpolation to partially upsample the observed hexagonal imagery and convert it to a rectangular grid. We then leverage a state-of-the-art convolutional neural network (CNN) architecture designed for SR …

Semi-Empirical Modeling Of Liquid Carbon's Containerless Solidification, Philip Chrostoski

Dissertations

Elemental carbon has important structural diversity, ranging from nanotubes through graphite to diamond. Previous studies of micron-size core/rim carbon spheres extracted from primitive meteorites suggest they formed around such stars via the solidification of condensed carbon-vapor droplets, followed by gas-to-solid carbon coating to form the graphite rims. Similar core/rim particles result from the slow cooling of carbon vapor in the lab. The long-range carbon bond-order potential was used to computationally study liquid-like carbon in (1.8 g/𝐜𝐦𝟑) periodic boundary (tiled-cube supercell) and containerless (isolated cluster) settings. Relaxations via conjugate-gradient and simulatedannealing nucleation and growth simulations using molecular dynamics were done to …

A Local Baseline Of The Black Hole Mass Scaling Relations For Active Galaxies. Iv. Correlations Between MBh And Host Galaxy Σ, Stellar Mass, And Luminosity, Vardha N. Bennert, Tommaso Treu, Xuheng Ding, Isak Stomberg, Simon Birrer, Tomas Snyder, Matthew A. Malkan, Andrew W. Stephens, Matthew W. Auger

Physics

The tight correlations between the mass of supermassive black holes (M_BH) and their host-galaxy properties have been of great interest to the astrophysical community, but a clear understanding of their origin and fundamental drivers still eludes us. The local relations for active galaxies are interesting in their own right and form the foundation for any evolutionary study over cosmic time. We present Hubble Space Telescope optical imaging of a sample of 66 local active galactic nuclei (AGNs); for 14 objects, we also obtained Gemini near-infrared images. We use state-of-the-art methods to perform surface photometry of the AGN host …

Automated Detection Of Bilingual Obfuscated Abusive Words On Social Media Forums: A Case Of Swahili And English Texts, Geofrey Njovangwa, Godfrey Justo

Tanzania Journal of Science

The usage of social media has exponentially grown in recent years leaving the users with no limitations on misusing the platforms through abusive contents as deemed fit to them. This exacerbates abusive words exposure to innocent users, especially in social media forums, including children. In an attempt to alleviate the problem of abusive words proliferation on social media, researchers have proposed different methods to help deal with variants of the abusive words; however, obfuscated abusive words detection still poses challenges. A method that utilizes a combination of rule based approach and character percentage matching techniques is proposed to improve the …

Experience Doesn't Matter, But The Direction Does, Hailey Blythe

The Journal of Purdue Undergraduate Research

No abstract provided.