Digital Commons Network^™

Investigation Of The Structural, Electronic, And Thermoelectric Properties Of Mono- Chalcogenides, Aida Sheibani

Graduate Theses and Dissertations

The structural, electronic, and thermoelectric properties of GeTe are studied using density functional theory and Boltzmann transport equations. This material has a rhombohedral crystal structure in ambient temperature with a ferroelectric behavior due to lack of inversion symmetry. This study suggests that the presence of asymmetry in GeTe can lead to an improvement in the thermoelectric properties of this material. In addition, studies on introducing Group III, IV, and V dopants to GeSe show that while these impurities can improve the power factor and decrease the lattice thermal conductivity, they cannot enhance the figure of merit.

Astroalign: A Python Module For Astronomical Image Registration, Martin Beroiz, Juan B. Cabral, Bruno Sanchez

Physics & Astronomy Faculty Publications

We present an algorithm implemented in the Astroalign Python module for image registration in astronomy. Our module does not rely on WCS information and instead matches three-point asterisms (triangles) on the images to find the most accurate linear transformation between them. It is especially useful in the context of aligning images prior to stacking or performing difference image analysis. Astroalign can match images of different point-spread functions, seeing, and atmospheric conditions.

The Origin Of The Universe: A Vast And Expanding Universe, Bienvenido F. Nebres Sj

Magisterial Lectures

In this video, Fr. Ben delivers a lecture for the course entitled Science, Technology, and Society (STS 10) about the beginnings of our universe: from the big bang, to now.

Speaker: Fr Bienvenido F Nebres, SJ is a Filipino scientist, mathematician, and Jesuit who was the longest-serving university president of the Ateneo de Manila University. He served as University President from 1993-2011. He received the title of National Scientist of The Philippines in 2011 for his contributions in the fields of STEM, education, and development.

The Origin Of The Universe: An Amazing And Mysterious Universe, Bienvenido F. Nebres Sj

Magisterial Lectures

In this video, Fr. Ben delivers a lecture for the course entitled Science, Technology, and Society (STS 10) about blackholes, stardust, and the forces that govern the universe.

Speaker: Fr Bienvenido F. Nebres S.J. is a Filipino scientist, mathematician, and Jesuit who was the longest-serving university president of the Ateneo de Manila University. He served as University President from 1993-2011. He received the title of National Scientist of The Philippines in 2011 for his contributions in the fields of STEM, education, and development.

Geochronology Of Massif-Type Anorthosites From The Ubendian Belt, Tanzania, Nelson Boniface

Tanzania Journal of Science

Massif-type anorthosites occur in East Africa at the margins of the Tanzania Craton in the Ubendian Belt. The massif assemblage constitutes of mafic-composition plutons (meta-anorthosite and meta-gabbro), ultramafic plutons, and titaniferous iron-ore. Silicic ortho-gneisses (tonalitic, dioritic, and granodioritic intrusives) also occur in the vicinity of the said massif-type anorthosites. This article presents ages of meta-anorthosites and meta-gabbros. The new U-Pb zircon age indicates that meta-gabbros and meta-anorthosites crystallized between 1915 ± 24 and 1905 ± 24 Ma concomitantly with the silicic magmatic bodies. Geochronological databases indicate that the period between 1920 and 1850 Ma HP-LT metamorphic interface was formed at …

Comparison Of Experimental And Monte Carlo Simulation Of Angular Distributions Of Bremsstrahlung Photons From 28-Ghz Electron Cyclotron Resonance (Ecr) Ion Source, Mwingereza Kumwenda

Tanzania Journal of Science

Angular distributions of deceleration radiation or bremsstrahlung in German, both experimental and simulated from Electron Cyclotron Resonance Ion Source (ECRIS) are not well understood so far. The bremsstrahlung photons of the angular distributions from 28-GHz ECR ion source at Busan Centre of Korea Basic Science Institute (KBSI) were measured in nine azimuthal angles for the first time. Three round type NaI(Tl) detectors were used to measure the angular distributions of the bremsstrahlung photons emitted at the extraction side of the ECRIS at the same time. Another NaI(Tl) detector was placed downstream from the ECR ion source for monitoring photon intensity. …

Variations Of Concentrations Of Lead, Zinc, Iron, Copper And Cadmium In Urine Of Primary School Pupils In Relation To Age, Sex And Academic Performance, John Mahugija, Zainab Kasenya, Kessy Kilulya

Tanzania Journal of Science

This study was conducted in order to assess the variations and correlations in the concentrations of lead, zinc, iron, copper and cadmium metals in the urine samples of selected primary school pupils with respect to their sex, age and academic performance. Urine samples were collected from 240 pupils in Dar es Salaam, Tanzania and then digested in concentrated acids and analysed using atomic absorption spectrometry (AAS). Lead, zinc, iron and copper were detected in most of the urine samples. Cadmium was not detected in any of the samples. The mean concentrations of lead, zinc, iron and copper in the samples …

Origin Of Sterile Neutrino Dark Matter Via Secret Neutrino Interactions With Vector Bosons, Kevin J. Kelly, Manibrata Sen, Walter Tangarife, Yue Zhang

Physics: Faculty Publications and Other Works

Secret neutrino interactions can play an essential role in the origin of dark matter. We present an anatomy of production mechanisms for sterile neutrino dark matter, a keV-scale gauge-singlet fermion that mixes with active neutrinos, in the presence of a new vector boson mediating secret interactions among active neutrinos. We identify three regimes of the vector boson’s mass and coupling where it makes a distinct impact on dark matter production through the dispersion relations and/or scattering rates. We also analyze models with gauged Lμ−Lτ and B−L numbers which have a similar dark matter cosmology but different vector boson phenomenology. We …

Circuits With Broken Fibration Symmetries Perform Core Logic Computations In Biological Networks, Ian Leifer, Flaviano Morone, Saulo D. S. Reis, José S. Andrade Jr., Mariano Sigman, Hernán A. Makse

Publications and Research

We show that logic computational circuits in gene regulatory networks arise from a fibration symmetry breaking in the network structure. From this idea we implement a constructive procedure that reveals a hierarchy of genetic circuits, ubiquitous across species, that are surprising analogues to the emblematic circuits of solid-state electronics: starting from the transistor and progressing to ring oscillators, current-mirror circuits to toggle switches and flip-flops. These canonical variants serve fundamental operations of synchronization and clocks (in their symmetric states) and memory storage (in their broken symmetry states). These conclusions introduce a theoretically principled strategy to search for computational building blocks …

Search For Lepton-Flavor-Violating Decays D0→X0E±Μ∓, J. P. Lees, V. Poireau, V. Tisserand, E. Grauges, A. Palano, G. Eigen, D. N. Brown, Yu G. Kolomensky, M. Fritsch, H. Koch, T. Schroeder, R. Cheaib, C. Hearty, T. S. Mattison, J. A. Mckenna, R. Y. So, V. E. Blinov, A. R. Buzykaev, V. P. Druzhinin, Milind Purohit, Et. Al.

Faculty Publications

We present a search for seven lepton-flavor-violating neutral charm meson decays of the type D⁰→X⁰e^±μ^∓, where X⁰ represents a π⁰, K ⁰ _S S, K^0* ρ⁰, ϕ, ω, or η meson. The analysis is based on 468 fb⁻¹ of e⁺e^- annihilation data collected at or close to the Υ(4S)resonance with the BABAR detector at the SLAC National Accelerator Laboratory. No significant signals are observed, and we establish 90% confidence level upper limits on the branching fractions in …

Two-Loop Corrections To The Large-Order Behavior Of Correlation Functions In The One-Dimensional N-Vector Model, L. T. Giorgini, Ulrich D. Jentschura, E. M. Malatesta, G. Parisi, T. Rizzo, J. Zinn-Justin

Physics Faculty Research & Creative Works

For a long time, the predictive limits of perturbative quantum field theory have been limited by our inability to carry out loop calculations to an arbitrarily high order, which become increasingly complex as the order of perturbation theory is increased. This problem is exacerbated by the fact that perturbation series derived from loop diagram (Feynman diagram) calculations represent asymptotic (divergent) series which limits the predictive power of perturbative quantum field theory. Here, we discuss an ansatz that could overcome these limits, based on the observations that (i) for many phenomenologically relevant field theories, one can derive dispersion relations which relate …

Probing The Two-Neutrino Exchange Force Using Atomic Parity Violation, Mitrajyoti Ghosh, Yuval Grossman, Walter Tangarife

Physics: Faculty Publications and Other Works

The exchange of two neutrinos at one loop leads to a long-range parity-violating force between fermions. We explore the two-neutrino force in the backdrop of atomic physics. We point out that this is the largest parity-violating long-range force in the Standard Model and calculate the effect of this force in experiments that probe atomic parity violation by measuring optical rotation of light as it passes through a sample of vaporized atoms. We perform explicit calculations for the hydrogen atom to demonstrate this effect. Although we find that the effect is too small to be observed in hydrogen in the foreseeable …

The Role Of Multiple Ionization In Fast Highly Charged Ions Collisions On H2o, N. Bachi, G. S. Otero, S. Otranto, Ronald E. Olson

Physics Faculty Research & Creative Works

An adaptive classical trajectory Monte Carlo model that explicitly considers the eight electrons corresponding to the valence molecular orbitals of the H₂O molecule is introduced. In this dynamical model, the electrons' binding energies change throughout the collision ensuring the proper energy deposition by the projectile for multiple electron removal. Present results are relevant to the ion-therapy program, specially at irradiation planning stages in which detailed information on the electronic emission spectra are needed as input data.

Optically Thick Radiating Free Convective Mhd Nanofluid Flow Over An Exponentially Accelerated Plate, D.P. Bhatta, S.R. Mishra, J.K. Dash

Karbala International Journal of Modern Science

The present analysis investigates an unsteady conducting water-based nanofluid embedding with porous medium over an exponentially accelerated vertical plate. The plate is accelerated with moving ramped temperature. However, water is treated as the base fluid with Copper (Cu) and Titanium Oxide (TiO₂) as nanoparticles. Effects of thermal radiation, heat source, and radiation absorption are taken care of in the energy equation which may enhance the heat transfer properties of nanofluid. The crux of the investigation is to find the closed-form solution of nonlinear coupled partial differential equations. Laplace Transform technique is employed to solve these equations. The influence …

An [O Iii] Search For Extended Emission Around Agn With Hi Mapping: A Distant Cloud Ionized By Mkn 1, Erin Darnell Knese, William C. Keel, Greg Knese, Vardha N. Bennert, Alexei Moiseev, Aleksandra Grokhovskaya, Sergei N. Dodonov

Physics

Motivated by the discovery of large ionized clouds around AGN, and particularly the large fraction of those that are consistent with photoionized gaseous tidal debris, we searched for [O III] emission around Seyfert galaxies previously mapped in H I, many with extended gas features. Of 26 Seyfert galaxies, we find one spatially extended emission feature, a discrete cloud projected ≈12 kpc SW from the centre of Mkn 1 and spanning a transverse extent of 8 kpc. Optical spectroscopy (Kast/Lick and SCORPIO/BTA) of this cloud confirms its association with the Mkn 1–NGC 451 galaxy pair, closely matching the kinematics of nearby …

Analytical Setup Margin For Spinal Sbrt Based On Measured Errors, Audrey Copeland

LSU Master's Theses

Purpose: No consensus currently exists in the radiotherapy community about the correct margin size to use for spinal SBRT. Margins have been proposed to account for various errors individually, but not with all errors combined to result in a single margin value. The purpose of this work was to determine a setup margin for spinal SBRT based on known and measurable errors during radiotherapy to achieve at least 90% coverage of the clinical target volume (CTV) with the prescription dose for at least 90% of patients and not exceed a 30 Gy point dose or 23 Gy to 10% of …

Surface Termination And Schottky-Barrier Formation Of In4Se3(001), Archit Dhingra, Pavlo V. Galiy, Lu Wang, Nataliia S. Vorobeva, Alexey Lipatov, Angel Torres, Taras M. Nenchuk, Simeon J. Gilbert, Alexander Sinitskii, Andrew J. Yost, Wai-Ning Mei, Keisuke Fukutani, Jia Shiang Chen, Peter Dowben

Peter Dowben Publications

The surface termination of In₄Se₃(001) and the interface of this layered trichalcogenide, with Au, was examined using x-ray photoemission spectroscopy. Low energy electron diffraction indicates that the surface is highly crystalline, but suggests an absence of C2v mirror plane symmetry. The surface termination of the In₄Se₃(001 is found, by angle-resolved x-ray photoemission spectroscopy, to be In, which is consistent with the observed Schottky barrier formation found with this n-type semiconductor. Transistor measurements confirm earlier results from photoemission, suggesting that In₄Se₃(001 is an n-type semiconductor, so that Schottky barrier …

Kinetic Exclusion Assay Of Biomolecules By Aptamer Capture, Mark H. Smith, Daniel Fologea

Physics Faculty Publications and Presentations

DNA aptamers are short nucleotide oligomers selected to bind a target ligand with affinity and specificity rivaling that of antibodies. These remarkable features recommend aptamers as candidates for analytical and therapeutic applications that traditionally use antibodies as biorecognition elements. Numerous traditional and emerging analytical techniques have been proposed and successfully implemented to utilize aptamers for sensing purposes. In this work, we exploited the analytical capabilities offered by the kinetic exclusion assay technology to measure the affinity of fluorescent aptamers for their thrombin target and quantify the concentration of analyte in solution. Standard binding curves constructed by using equilibrated mixtures of …

Improving The Understanding Of Jet Grooming In Perturbation Theory, Andrew J. Larkoski

Portland Institute for Computational Science Publications

Jet grooming has emerged as a necessary and powerful tool in a precision jet physics program. In this paper, we present three results on jet grooming in perturbation theory, focusing on heavy jet mass in e⁺e⁻ → hadrons collisions, groomed with the modified mass drop tagger. First, we calculate the analytic cross section at leading-order. Second, using the leading-order result and numerical results through next-to-next-to-leading order, we show that cusps in the distribution on the interior of phase space at leading-order are softened at higher orders. Finally, using analytic and numerical results, we show that terms that …

Mechani-Kits Senior Design Project, Jake Utley, Sophie Carson, Vincent Seguin

Mechanical Engineering

Studies suggest that when designed and executed well, hands-on activities can enhance student understanding of key mechanics concepts. Current products are expensive and typically not designed to meet a variety of learning objectives. Through the Mechanics of Inclusion and Inclusivity in Mechanics grant, the Cal Poly Physics and Engineering Departments are seeking to incorporate new hands-on activities into their courses. Our team has designed three inexpensive ”MechaniKits” to be used in physics, statics and dynamics courses [1]. This Final Design Review outlines our findings, objectives, and final designs for this project. It also explains our manufacturing and design verification plans. …

Radio Observations Of The Neutron Star X-Ray Binary Circinus X-1: Clues On The Onset Of Radio Emission And Jet Formation, Batool Ahmad Essa Saleh Ilyasi

Theses

Circinus X-1 is a Neutron-Star X-ray Binary System which features strong and variable radio emission. This emission is triggered as a result of the interaction between neutron star and its companion as they approach periastron. Radio observations of Circinus X-1 have not been carried out over the past 7 years. Here are the results of the radio observation and monitoring campaign on Circinus X-1 with the Australia Telescope Compact Array (ATCA) – Australia, at centimeter wavelengths (5.5 and 9 GHz). The radio behavior of Circinus X-1 has been monitored over two of its orbits (16.6 days each) to probe its …

Deep Minima In The Triply Differential Cross Section For Ionization Of Atomic Hydrogen By Electron And Positron Impact, C. M. Demars, S. J. Ward, J. Colgan, S. Amami, Don H. Madison

Physics Faculty Research & Creative Works

We investigate ionization of atomic hydrogen by electron-and positron-impact. We apply the Coulomb-Born (CB1) approximation, various modified CB1 approximations, the three-body distorted wave (3DW) approximation, and the time-dependent close-coupling (TDCC) method to electron-impact ionization of hydrogen. For electron-impact ionization of hydrogen for an incident energy of approximately 76.45 eV, we obtain a deep minimum in the CB1 triply differential cross section (TDCS). However, the TDCC for 74.45 eV and the 3DW for 74.46 eV gave a dip in the TDCS. For positron-hydrogen ionization (breakup) we apply the CB1 approximation and a modified CB1 approximation. We obtain a deep minimum in …

Spectroscopic And Structural Probing Of Excited-State Molecular Dynamics With Time-Resolved Photoelectron Spectroscopy And Ultrafast Electron Diffraction, Yusong Liu, Spencer L. Horton, Jie Yang, J. Pedro F. Nunes, Xiaozhe Shen, Thomas J.A. Wolf, Ruaridh Forbes, Chuan Cheng, Bryan Moore, Martin Centurion, Kareem Hegazy, Renkai Li, Ming Fu Lin, Albert Stolow, Paul Hockett, Tamás Rozgonyi, Philipp Marquetand, Xijie Wang, Thomas Weinacht

Martin Centurion Publications

Pump-probe measurements aim to capture the motion of electrons and nuclei on their natural timescales (femtoseconds to attoseconds) as chemical and physical transformations take place, effectively making "molecular movies"with short light pulses. However, the quantum dynamics of interest are filtered by the coordinate-dependent matrix elements of the chosen experimental observable. Thus, it is only through a combination of experimental measurements and theoretical calculations that one can gain insight into the internal dynamics. Here, we report on a combination of structural (relativistic ultrafast electron diffraction, or UED) and spectroscopic (time-resolved photoelectron spectroscopy, or TRPES) measurements to follow the coupled electronic and …

Generating Entanglement With The Dynamical Lamb Effect, Mirko Amico

Dissertations, Theses, and Capstone Projects

According to quantum field theory, the vacuum is filled with virtual particles which can be turned into real ones under the influence of external perturbations. Phenomena of this kind are commonly referred to as quantum vacuum phenomena. Several quantum vacuum phenomena related to the peculiar nature of the quantum vacuum have been predicted, some of which, such as the Lamb shift and the Casimir effect, have been experimentally found. Other examples of quantum vacuum phenomena include the Unruh effect, the dynamical Casimir effect and the dynamical Lamb effect. The dynamical Lamb effect was first predicted by considering the situation of …

Small-X Qcd Calculations With A Biased Ensemble, Gary Kapilevich

Dissertations, Theses, and Capstone Projects

In this dissertation, I will argue that we can study functional fluctuations in unintegrated gluon distributions, in the MV model as well as JIMWLK, using reweighting techniques, which will allow me to calculate QCD observables with "biased ensembles". This technique will enable me to study rare functional configurations of the gluon distributions, that might have been selected for in, for example, the centrality criteria used by the ATLAS and ALICE collaborations. After a review of these techniques, as well as a review of QCD physics at high energy in general, I will use biased ensembles to compute observables in two …

Generalized Four-Dimensional Effective Hadronic Supersymmetry Based On Quantum Chromodynamics (Qcd), Enxi Yu

Dissertations, Theses, and Capstone Projects

New discovery in multiple laboratories around the globe has shown a supersymmetry between hadrons—baryons and mesons. In order to generalize the phenomenological hadronic supersymmetry, the spin-flavor SU(6) symmetry need an extension. This thesis present how we can extend SU(6) symmetry so that hadronic supersymmetry can be included. In the future, this extension can be also applied to pentaquark and tetraquark bags, for which there is an ongoing research in laboratories.

Proton Pumping Mechanism In Cytochrome C Oxidase, Xiuhong Cai

Dissertations, Theses, and Capstone Projects

Cytochrome c Oxidase (CcO), is the terminal electron acceptor in the membrane bound aerobic respiratory chain. It reduces O₂ to water. The energy released by this reaction is stored by pumping protons from the high pH, N-side of the membrane to the low pH, P-side. The generated proton gradient provides the motive force for synthesis of ATP by the ATP synthase.

Building a proton gradient across the membrane requires that proton transport must occur along controllable proton pathways to prevent proton leakage to the N-side. It has been suggested that CcO function requires proton transfer channels in both the …

Data Assimilation For Conductance-Based Neuronal Models, Matthew Moye

Dissertations

This dissertation illustrates the use of data assimilation algorithms to estimate unobserved variables and unknown parameters of conductance-based neuronal models. Modern data assimilation (DA) techniques are widely used in climate science and weather prediction, but have only recently begun to be applied in neuroscience. The two main classes of DA techniques are sequential methods and variational methods. Throughout this work, twin experiments, where the data is synthetically generated from output of the model, are used to validate use of these techniques for conductance-based models observing only the voltage trace. In Chapter 1, these techniques are described in detail and the …

Waiting-Time Paradox In 1922, Naoki Masuda, Takayuki Hiraoka

Northeast Journal of Complex Systems (NEJCS)

We present an English translation and discussion of an essay that a Japanese physicist, Torahiko Terada, wrote in 1922. In the essay, he described the waiting-time paradox, also called the bus paradox, which is a known mathematical phenomenon in queuing theory, stochastic processes, and modern temporal network analysis. He also observed and analyzed data on Tokyo City trams to verify the relevance of the waiting-time paradox to busy passengers in Tokyo at the time. This essay seems to be one of the earliest documentations of the waiting-time paradox in a sufficiently scientific manner.

Hyperpolarizability Dispersion Measured For Cs2 Vapor, Rodrigo N. Fernandez, David P. Shelton

Physics & Astronomy Faculty Research

The second hyperpolarizability (��) of carbon disulfide (CS2) is measured by gas-phase electric-field-induced second-harmonic generation for laser wavelengths in the range 765–1064 nm. The observed hyperpolarizability is decomposed into electronic (����) and vibrational (����) contributions, and the dispersion curve for ���� is extrapolated to the static limit, with the result of ����0=12558±93 atomic units =7.83±0.06×10−61C4m4J−3=6.33±0.0×10−36 esu (Taylor series convention). The results of this experiment agree with other recent nonlinear optical measurements and theoretical calculations.