Physical Sciences and Mathematics Commons^™

Analytic Derivative Couplings Between Configuration-Interaction-Singles States With Built-In Electron-Translation Factors For Translational Invariance, Shervin Fatehi, Ethan Alguire, Yihan Shao, Joseph Subotnik

Chemistry Faculty Publications and Presentations

We present a method for analytically calculating the derivative couplings between a pair of configuration-interaction-singles (CIS) excited states obtained in an atom-centered basis. Our theory is exact and has been derived using two completely independent approaches: one inspired by the Hellmann-Feynman theorem and the other following from direct differentiation. (The former is new, while the latter is in the spirit of existing approaches in the literature.) Our expression for the derivative couplings incorporates all Pulay effects associated with the use of an atom-centered basis, and the computational cost is minimal, roughly comparable to that of a single CIS energy gradient. …

User Choice Between Traditional And Computerized Methods: An Activity Perspective, Jun Sun

Information Systems Faculty Publications and Presentations

Numerous computerized methods emerge to replace traditional methods in people’s personal, work and social lives, but many are hesitant to make the transition. This study examines the factors that influence human choice between different methods. According to Activity Theory, traditional and computerized methods are both tools that a person uses for a certain task. The situated experiences with various methods shape people’s attitude toward using them later in terms of tool readiness. The understanding leads to hypothesized relationships between user-, method- and task-specific factors and the dependent variable. The results from an empirical study support that method experiences have strong …

First Mover: Otto Struve And The Use Of Scientific Capital In Astrophysics, 1921–1950, Erik Paul Norquest

Theses and Dissertations - UTB/UTPA

Otto Struve (1897-1963) came to the United States in 1921 and became one of the dominant personalities in the field of astrophysics. Struve’s career made him, in the words of sociologist Pierre Bourdieu, a “first mover” in a scientific field that was firmly engaged in the process of what Thomas Kuhn called “normal science.” Struve pulled astrophysics further away from its empirical roots in categorization and made it more like physics in its unification of theory and observation. The primary way that he accomplished this was through his administration of Yerkes and McDonald observatories, where he brought in theorists to …

Fabrication Of Mineralized Collagen From Bovine Waste Materials By Hydrothermal Method As Promised Biomaterials, Faheem A. Sheikh, M. A. Kanjwal, Javier Macossay-Torres, Muneeb A. Muhammad, Travis Cantu, Ioannis S. Chronakis, N. A. M. Barakat, Hak Yong Kim

Chemistry Faculty Publications and Presentations

In the present study, we aimed to produce mineralized-collagen by hydrothermal process. A simple method not depending on additional foreign chemicals has been employed to isolate the mineralized-collagen fibers from bovine waste. The process of extraction involves the use of hydrothermal method from available bovine bones. The structural and morphological properties of the collagen fibers were characterized by using scanning electron microscopy and transmission electron microscopy. These results indicated well received collagen fibers, having a diameter less than 1 μm and with established mineral content in the individual fibers. The X-ray diffraction showed the crystalline feature of the obtained nano-compounds. …

A Gravitational Wave Observatory Operating Beyond The Quantum Shot-Noise Limit: Squeezed Light In Application, J. Abadie, B. P. Abbott, T. D. Abbott, M. R. Abernathy, Matthew Benacquista, Teviet Creighton, H. Daveloza, Maria E. Diaz, R. Grosso, Soumya Mohanty, Soma Mukherjee, Volker Quetschke, Joseph D. Romano, Robert Stone, A. S. Stroeer

Physics and Astronomy Faculty Publications and Presentations

Around the globe several observatories are seeking the first direct detection of gravitational waves (GWs). These waves are predicted by Einstein's general theory of relativity(1) and are generated, for example, by black-hole binary systems(2). Present GW detectors are Michelson-type kilometre-scale laser interferometers measuring the distance changes between mirrors suspended in vacuum. The sensitivity of these detectors at frequencies above several hundred hertz is limited by the vacuum (zero-point) fluctuations of the electromagnetic field. A quantum technology-the injection of squeezed light(3)-offers a solution to this problem. Here we demonstrate the squeezed-light enhancement of GEO 600, which will be the GW observatory …

A Comprehensive Method For Fractionating Soil Organic Matter Not Protected And Protected From Decomposition By Physical And Chemical Mechanisms, César Plaza, José M. Fernández, Engil Isadora Pujol Pereira, Alfredo Polo

School of Earth, Environmental, and Marine Sciences Faculty Publications and Presentations

The objective of this work was to describe a method for isolating meaningful and measurable soil organic matter (SOM) pools that differ in the mechanisms by which they are protected from decomposition. The proposed method is appropriate for soil C stabilization and sequestration studies. Unlike previous fractionation schemes, this procedure allows free SOM located between aggregates (unprotected C pool) and SOM occluded within both macroaggregates and microaggregates (C weakly and strongly protected by physical mechanisms, respectively) to be recovered separately, freed from the soil mineral matrix and the mineral-associated SOM pool (C pool protected by chemical mechanisms) and thus well …

Infrared And Upconversion Spectroscopic Studies Of High Er3+Content Transparent Yag Ceramic, M. Pokhrel, G. A. Kumar, P. Samuel, K. I. Ueda, T. Yanagitani, H. Yagi, D. K. Sardar

Physics and Astronomy Faculty Publications and Presentations

In this article, we report the detailed spectroscopic studies of high Er3+content (50%) transparent YAG ceramic co-doped with nominal Cr3+ content (0.1 mol %). Various radiative and non-radiative spectroscopic properties such as radiative decay time, fluorescence branching ratio, emission/absorption cross sections, internal radiative quantum yields of the infrared and the upconverted emission bands are explored using standard experimental and theoretical methods and compared with YAG single crystal. Results show that although the non-radiative losses are high for 50% Er doped ceramic; several radiative spectral properties are almost in agreement with those for the single crystal YAG. Furthermore, because of the …

The Properties Of The Stellar Nuclei With The Host Galaxy Morphology In The Acsvcs, Hyun-Chul Lee

Physics and Astronomy Faculty Publications and Presentations

We have revisited the ACS Virgo Cluster Survey (ACSVCS), a Hubble Space Telescope program to obtain ACS/WFC g and z bands imaging for a sample of 100 early-type galaxies in the Virgo Cluster. In this study, we examine 51 nucleated early-type galaxies in the ACSVCS in order to look into the relationship between the photometric and structural properties of stellar nuclei and their host galaxies. We morphologically dissect galaxies into five classes. We note that (1) the stellar nuclei of dwarf early-type galaxies (dS0, dE, and dE,N) are generally fainter and bluer with g > 18.95 and (g-z) < 1.40 compared to some brighter and redder counterparts of the ellipticals (E) and lenticular galaxies (S0), (2) the g-band half-light radii of stellar nuclei of all dwarf early-type galaxies (dS0, dE, and dE,N) are smaller than 20 pc and their average is about 4 pc, and (3) the colors of red stellar nuclei with (g - z) > 1.40 in bright …

Tidal Perturbations To The Gravitational Inspiral Of J0651+2844, Matthew J. Benacquista, Kelly Holley-Bockelmann

Physics and Astronomy Faculty Publications and Presentations

The recently discovered J0651+2844 is a detached, eclipsing white dwarf binary with an orbital period of 765 s. We investigate the prospects for the detection of gravitational radiation from this system and estimate the effect of the tidal deformation of the low-mass component on the period evolution of the system. Because of the high inclination of the system, the amplitude of the gravitational waves at Earth will be as much as a factor of two lower than that from an optimally oriented system. The dominant contribution of tidal corrections to the period evolution comes from the increase in rotational energy …

Polycyclic Aromatic Compounds As Anticancer Agents: Evaluation Of Synthesis And In Vitro Cytotoxicity, Debasish Bandyopadhyay, Jose C. Granados, John D. Short, Bimal K. Banik

Chemistry Faculty Publications and Presentations

Polycyclic aromatic hydrocarbons (PAHs) are considered to be significant environmental carcinogens. Additionally, various planar ring systems are capable of intercalating with DNA, leading to a number of drugs that possess chemotherapeutic activity. In this study, three new polyaromatic compounds with a side chain were synthesized, and spectroscopic as well as elemental analyses were performed. The addition of the long chains to either chrysene or pyrene caused a red-shift in the spectral emission when compared to the corresponding polycyclic aromatic hydrocarbons itself. Furthermore, the cytotoxicity of the three novel polyaromatic compounds was evaluated in vitro in a panel of cultured mammalian …

A Truly Green Synthesis Of A-Aminonitriles Via Strecker Reaction, Debasish Bandyopadhyay, Juliana M. Velazquez, Bimal K. Banik

Chemistry Faculty Publications and Presentations

Background: The classical Strecker reaction is one of the simplest and most economical methods for the synthesis of racemic a-aminonitriles (precursor of a-amino acids) and pharmacologically useful compounds.

Results: Indium powder in water is shown to act as a very efficient catalyst for one-pot, three-component synthesis of a-aminonitriles from diverse amines, aldehydes and TMSCN. This general rapid method is applicable to a wide range of amines and aldehydes and produces products in excellent yield.

Conclusions: The present one-pot, three-component environmentally benign procedure for the synthesis of aaminonitriles will find application in the synthesis of complex biologically active molecules.

Sparse Spectral-Tau Method For The Three-Dimensional Helically Reduced Wave Equation On Two-Center Domains, Stephen R. Lau, Richard H. Price

Physics and Astronomy Faculty Publications and Presentations

We describe a multidomain spectral-tau method for solving the three-dimensional helically reduced wave equation on the type of two-center domain that arises when modeling compact binary objects in astrophysical applications. A global two-center domain may arise as the union of Cartesian blocks, cylindrical shells, and inner and outer spherical shells. For each such subdomain, our key objective is to realize certain (differential and multiplication) physical-space operators as matrices acting on the corresponding set of modal coefficients. We then achieve sparse realizations through the integration “preconditioning” of Coutsias, Hagstrom, Hesthaven, and Torres. Since ours is the first three-dimensional multidomain implementation of …

Bismuth Nitrate Pentahydrate-Induced Novel Nitration Of Eugenol, Luis Canales, Debasish Bandyopadhyay, Bimal K. Banik

Chemistry Faculty Publications and Presentations

Background: Eugenol, the main constituent of clove oil possesses a number of medicinal activities. To enhance the medicinal property, structural modification is required. On the other hand, bismuth nitrate pentahydrate has been established as an excellent eco-friendly nitrating agent for several classes of organic compounds.

Results: Bismuth nitrate pentahydrate-induced nitration of eugenol has been investigated very thoroughly. Twenty five different conditions have been studied. The microwave-induced solvent-free reaction has been identified as the best condition.

Conclusions: Spectral analyses confirm that 5-nitroeugenol is the sole product in all the cases. No oxidized or isomerized product could be detected.

Compact Binaries In Star Clusters - Ii. Escapers And Detection Rates, J. M.B. Downing, M. J. Benacquista, M. Giersz, R. Spurzem

Physics and Astronomy Faculty Publications and Presentations

We use a self-consistent Monte Carlo treatment of stellar dynamics to investigate black hole binaries that are dynamically ejected from globular clusters in order to determine if they will be gravitational wave sources. We find that many of the ejected binaries initially have short periods and will merge within a Hubble time due to gravitational wave radiation. Thus they are potential sources for ground-based gravitational wave detectors. We estimate the yearly detection rate for current and advanced ground-based detectors and find an enhancement over the rate predicted for binaries produced by pure stellar evolution in galactic fields. We conclude that, …

Ferromagnetic Resonance On Ni Nanowire Arrays, Mircea Chipara, Ralph Skomski, Roger D. Kirby, David J. Sellmyer

Physics and Astronomy Faculty Publications and Presentations

Ferromagnetic resonance investigations on Ni nanowires are reported. The angular dependence of the resonance line position is analyzed within a thermodynamic approach that includes shape anisotropy (ellipsoids of revolution), magnetocrystalline anisotropies (cubic and uniaxial), and dipole–dipole interactions. The results are supported by hysteresis loops, obtained on the same sample.

Beating The Spin-Down Limit On Gravitational Wave Emission From The Vela Pulsar, J. Abadie, B. P. Abbott, R. Abbott, M. Abernathy, T. Accadia, F. Acernese, C. Adams, R. Adhikari, C. Affeldt, B. Allen, G. S. Allen, E. Amador Ceron, D. Amariutei, R. S. Amin, S. B. Anderson, W. G. Anderson, F. Antonucci, K. Arai, M. A. Arain, M. C. Araya, S. M. Aston, P. Astone, D. Atkinson, P. Aufmuth, C. Aulbert, B. E. Aylott, S. Babak, P. Baker, G. Ballardin, S. Ballmer

Physics and Astronomy Faculty Publications and Presentations

We present direct upper limits on continuous gravitational wave emission from the Vela pulsar using data from the Virgo detector's second science run. These upper limits have been obtained using three independent methods that assume the gravitational wave emission follows the radio timing. Two of the methods produce frequentist upper limits for an assumed known orientation of the star's spin axis and value of the wave polarization angle of, respectively, 1.9 × 10-24 and 2.2 × 10-24, with 95% confidence. The third method, under the same hypothesis, produces a Bayesian upper limit of 2.1 × 10-24, with 95% degree of …

Structural Basis For Sequence Specific Dna Binding And Protein Dimerization Of Hoxa13, Yonghong Zhang, Christine A. Larsen, H. Scott Stadler, James B. Ames

Chemistry Faculty Publications and Presentations

The homeobox gene (HOXA13) codes for a transcription factor protein that binds to AT-rich DNA sequences and controls expression of genes during embryonic morphogenesis. Here we present the NMR structure of HOXA13 homeodomain (A13DBD) bound to an 11-mer DNA duplex. A13DBD forms a dimer that binds to DNA with a dissociation constant of 7.5 nM. The A13DBD/DNA complex has a molar mass of 35 kDa consistent with two molecules of DNA bound at both ends of the A13DBD dimer. A13DBD contains an N-terminal arm (residues 324 - 329) that binds in the DNA minor groove, and a C-terminal helix (residues …

The First-Integral Method For Duffing-Van Der Pol-Type Oscillator System, Xiaochuan Hu

Theses and Dissertations - UTB/UTPA

In this thesis, we restrict our attention to nonlinear Duffing–van der Pol–type oscillator system by means of the First-integral method. This system has physical relevance as a model in certain flow-induced structural vibration problems, which includes the van der Pol oscillator and the damped Duffing oscillator etc as particular cases. Firstly we apply the Division Theorem for two variables in the complex domain, which is based on the ring theory of commutative algebra, to explore a quasi-polynomial first integral to an equivalent autonomous system. Then through a certain parametric condition, we derive a more general first integral of the Duffing–van …

Zero Inflated Exponential Distribution And It's Variants, Sougata Dhar

Theses and Dissertations - UTB/UTPA

There have been a lot of studies with respect to the popular Zero Inflated versions of some discrete distributions, like Zero Inflated Poisson and Zero Inflated Negative Binomial distributions. They arise naturally in the literature when one aims to model count data sets having more than usual number of zeros by well known probability distributions. But it can be argued and established that Zero Inflated versions of continuous distributions also make sense. In this thesis, we first provide some motivations for studying Zero Inflated versions of exponential distribution and its variants and then study some parametric and Bayesian aspects related …

Mathematics Of Synthetic Aperture Radar Imaging, Guillermo Garza

Theses and Dissertations - UTB/UTPA

In Synthetic Aperture Radar (SAR) imaging, radar antennas are mounted on an airborne platform. The scene to be imaged is illuminated by electromagnetic waves transmitted from an antenna. The goal is to extract information of the scene from the measurements taken of the scattered waves. Reconstructing an image of the scene is an inverse problem. In this thesis, we study a method of image reconstruction developed by formulating the data collected as a Fourier integral operator acting on the scene, then applying an approximate inverse operator to that data. In particular, we examine the effects of bistatic system geometry to …

Collapsing Of Non Homogeneous Markov Chains, Agnish Dey

Theses and Dissertations - UTB/UTPA

In this thesis we have considered questions about lumpability of a non homogeneous markov chain. A number of results similar to those obtained in [2] in the case of homogeneous markov chains have been presented here. We have also considered a few results along the lines of those considered in [8].

Benchmarking Bottom-Up And Top-Down Strategies To Sparql-To-Sql Query Translation, Andrii Kashliev

Theses and Dissertations - UTB/UTPA

Many researchers have proposed using conventional relational databases to store and query large Semantic Web datasets. The most complex component of this approach is SPARQL-to-SQL query translation. Existing algorithms perform this translation using either bottom-up or top-down strategy and result in semantically equivalent but syntactically different relational queries. Do relational query optimizers always produce identical query execution plans for semantically equivalent bottom-up and top-down queries? Which of the two strategies yields faster SQL queries? To address these questions, this work studies bottom-up and top-down translations of SPARQL queries with nested optional graph patterns. This work presents: (1) A basic graph …

Qualitative Analysis To A Nonlinear System, Pengcheng Xiao

Theses and Dissertations - UTB/UTPA

In this thesis, we first present a qualitative analysis to a nonlinear system under certain parametric conditions. Then for a special case, we make a series of variable transformation and apply the Prelle-Singer Method to find the first integrals of the simplified equations without complicated calculations. Through the inverse transformations we get the first integrals of the original equation. Finally, we use the same Prelle-Singer method to get the first integral for an extended nonlinear system.

Subdifferentials Of Distance Functions And Applications To Facility Location Problems, Juan Salinas Jr.

Theses and Dissertations - UTB/UTPA

The classical Heron problem states: on a given straight line in the plane, find a point C such that the sum of the distances from C to the given points A and B is minimal. This problem can be solved using standard geometry or differential calculus. In the light of modern convex analysis, we are able to investigate more general versions of this problem. In this thesis we propose and solve the following problem: on a given nonempty closed convex subset of IRs , find a point such that the sum of the distances from that point to n given …

Modeling Instabilities Of Electrically Driven Jets Under Constant Or Variable Applied Field And Non-Zero Basic State Velocity, Sayantan Das

Theses and Dissertations - UTB/UTPA

We investigate the problem of instability of electrically forced axisymmetric jets with respect to temporally and spatially growing disturbances, within parameter regimes that affects the process of electrospinnning. Deriving a dispersion relation based on the relevant approximated versions of the equations of the electro-hydrodynamics for an electrically forced jet flow. For temporal instability, we find in the non-zero basic state velocity, the growth rate of the unstable mode is unaffected by the value of the basic state velocity. But, the basic state velocity affects the period of the unstable mode in the sense that it decreases the period, and the …

Intractability Of Integration And Derivative For Multivariate Polynomial And Trigonometric Function, Liang Ding

Theses and Dissertations - UTB/UTPA

We study the hardness of some basic linear operators which involve high dimension integration or derivative. For a multivariate polynomial ��(��1, ⋯ , ����) which has format ∏ ∑ ��1, we show that there is no any factor polynomial time approximation for the integration of ��(��1, ⋯ , ����) in the unit cube [0,1] �� unless P = NP. In addition to polynomials, we extend the discussion to nonlinear function. For a trigonometric function ��(��1, ⋯ , ����) of format ∏ ∑ �������� ∗ , we show that it is #P-hard to compute derivative ����(��) (��1,⋯,����) ����1⋯������ at the origin …

Chemical Education Experiences From The English Language Learner Perspective, Annette Flores

Theses and Dissertations - UTB/UTPA

The Rio Grande Valley (RGV) is a region populated by Spanish-speaking immigrants and their descendants producing a large English Language Learner (ELL) student population. ELLs have historically had low literacy rates and achievement levels when compared to their counterparts. In order to address this achievement gap, previous research efforts and curriculum interventions have focused on language acquisition as being the determining factor in ELL education, with little attention given to academic content acquisition. More current research efforts have transitioned into English language acquisition through academic content instruction; this present research study specifically focuses on ELL experiences in chemistry. Participants were …

Creation Of Post Ap Chemistry Class, Julian Medrano

Theses and Dissertations - UTB/UTPA

The creation of a Post AP Chemistry Class to be taught at the high school level for grade 12 students is discussed. The class is to be taught under the supervision of the University of Texas Pan American professors and taught by an MS Chemistry teacher, in order to better transition students into upper level chemistry courses beyond Chemistry 1401 and 1402.

Inverse Synthetic Aperture Radar Imaging Theory And Application, Jaime Xavier Lopez

Theses and Dissertations - UTB/UTPA

Inverse Synthetic Aperture Radar (ISAR) is an electromagnetic sensing system that is capable of producing high resolution microwave images of moving targets. Despite being developed within the engineering community, the theory of radar imaging is a subject of tremendous mathematical richness. The theory of ISAR imaging alone is filled with many applications and open problems that the mathematician and physicist may find interesting. In this thesis, the basis for a filtered back projection imaging algorithm is derived from a popular scalar wave model. This imaging algorithm is based on a filtered-adjoint method for inverting ISAR data, and allows for the …

Investigating Students' Mental Models And Knowledge Construction Of Microscopic Friction. I. Implications For Curriculum Design And Development, Edgar D. Corpuz, N. Sanjay Rebello

Physics and Astronomy Faculty Publications and Presentations

In this paper, we discuss the first phase of a multiphase study aimed at investigating the dynamics of students' knowledge construction in the context of unfamiliar physical phenomenon-microscopic friction. The first phase of this study involved the investigation of the variations in students' mental models of microscopic friction. Clinical interviews were conducted with 11 students enrolled in conceptual modern physics to elicit their ideas and generate themes of explanations. A phenomenographic approach of data analysis was employed to establish the variations in students' explanations. Results show that students' mental models of friction at the atomic level are dominated by their …