Physical Sciences and Mathematics Commons^™

Luminescent Properties Of Ensemble And Individual Erbium-Doped Yttrium Oxide Nanotubes, Yuanbing Mao, Xia Guo, Thai Tran, Kang L. Wang, C. Ken Shih, Jane P. Chang

Chemistry Faculty Publications and Presentations

The luminescent properties, including cathodoluminescence and photoluminescence, of the erbium-doped yttrium oxide (Er3+: Y2 O3) nanotubes (NTs) have been systematically studied. These NTs were synthesized by a hydrothermal treatment followed by a dehydration process. Cathodoluminescent measurements show that every Er3+: Y2 O3 NT is luminescent under electron excitation. In the near-infrared region, sharp, well-resolved, pump-power-dependent, and thermally stable photoluminescence was observed from ensemble NTs. Individual NTs also present characteristic luminescent emissions in the same spectral region. These properties make these NTs promising for applications in display, bioanalysis, and telecommunication.

Impact Of Flash Animation In Learning Concepts Of Matter Among Elementary Students, Rhodora S. Santos

Theses and Dissertations - UTB/UTPA

This study examines the instructional effect of flash animation on students' achievement in learning specific concepts of matter. The subjects used in this study were 5th-grade students of the researcher from Dan Ramirez Elementary. Each class or section of these students was randomly assigned as the control group (n = 20) and the experimental group (n =20). The subjects in the control group were exposed to traditional textbook reading while the subjects in the experimental group were exposed to flash animation. To measure the students' achievement from the concepts learned, a pre-test and a post test were both administered to …

Synthesis And Characterization Of Two Metal-Organic Frameworks, Roxanna Schaffino Moore

Theses and Dissertations - UTB/UTPA

Herein, the design and synthesis of two metal-organic frameworks, Zn 4O(FMA)3 (FMA = fumaric acid) and Zn2(CNC) 2(DPT) (CNC = 4-carboxycinnamic acid; DPT = 3,6-Di-4-pyridy1-1,2,4,5-tetrazine) via solvothermal methods are reported. Zn4O(FMA)3 was isolated as light yellow cubic crystals and Zn2(CNC)2(DPT) as light pink-block shaped crystals. The structures of both MOFs were characterized by single X-ray diffraction. Integrity of both MOFs were determined via powder X-ray diffraction and thermal gravimetric analysis. Zn4O(FMA) 3 is an isoreticular MOF exhibiting 6.8 Å pores taking up 5.2 wt % of hydrogen gas at 40 bar and 77K. Zn2(CNC)2(DPT) is a 3D primative cubic net …

Completing Chemistry Taks Objective 4(9d): The Effect Of Flash Animation, Judith B. Dano

Theses and Dissertations - UTB/UTPA

This study examines the effect of flash animation on learning effectiveness. The main goal of the study was to verify if using flash animation on learning chemistry concepts particularly Chemistry TAKS Objective 4 (9D) will have an impact on students learning achievement. The subjects in this study were 10th grade students from PSJA Memorial High School. Two class sections were randomly assigned as the treatment group each with 20 subjects (n=40) and another two class sections were assigned as the control group (n=40). The treatment group was exposed to flash animation while the control group had the traditional lecture type …

Electrospinning Polystyrene Reinforced With Multi-Walled Carbon Nanotubes: Parameters For Obtaining Nanofibers With Enhanced Thermal Properties, Ana Veronica Rodriguez Ybarra

Theses and Dissertations - UTB/UTPA

Various concentrations of multi-walled carbon nanotubes (MWCNTs) were dispersed in a polystyrene matrix in order to determine the optimal MWCNT concentration that would enhance the thermal properties of the composite. The MWCNTs were dispersed in the polystyrene matrix by high energy sonication and then electrospun. The microstructural characterization such as fiber diameter, fiber orientation, fiber morphology, porosity, cross-section shape, and surface roughness of the nanofibers electrospun from these composites were made by scanning electron microscopy and transmission electron microscopy. Spectroscopic characterization for these nanofibers was conducted using Fourier Transform infrared spectroscopy and Raman spectroscopy was utilized to establish a nanotube/matrix …

A Comparative Study Of Risk Factors Involved In Diabetes Between Texas And Other States, Andres Padilla Oviedo

Theses and Dissertations - UTB/UTPA

Diabetes is a serious concern in the United States and Texas is a state with high percentage of diabetes. The risk factors contributing to diabetes are current smoking, high blood cholesterol, hypertension, physical inactivity etc. In this thesis, we would like to identify the crucial risk factors for Texas. This motivates us to use the online data resources for a comparative study between Texas and other states. Looking at the data, we decide to use independent sample t-tests and independent sample non parametric tests [Wilcoxon Mann Whitney] for such comparative studies. This analysis has two parts – in the first …

Microwave-Assisted Ruthenium Trichloride-Catalyzed Synthesis Of Pyrrole Fused With Indole System In Water, Debasish Bandyopadhyay, Antara Banik, Sahil Bhatta, Bimal K. Banik

Chemistry Faculty Publications and Presentations

A simple and efficient microwave-induced ruthenium trichloride-catalyzed synthesis of pyrrole fused with indole system in water is developed by reacting commercially available isatin and 4-hydroxyproline.

Tempo2: A New Pulsar Timing Package - Iii. Gravitational Wave Simulation, G. Hobbs, F. Jenet, K. J. Lee, J. P.W. Verbiest, D. Yardley, R. Manchester, A. Lommen, W. Coles, R. Edwards, C. Shettigara

Physics and Astronomy Faculty Publications and Presentations

Analysis of pulsar timing data sets may provide the first direct detection of gravitational waves. This paper, the third in a series describing the mathematical framework implemented into the TEMPO2 pulsar timing package, reports on using TEMPO2 to simulate the timing residuals induced by gravitational waves. The TEMPO2 simulations can be used to provide upper bounds on the amplitude of an isotropic, stochastic, gravitational wave background in our Galaxy and to determine the sensitivity of a given pulsar timing experiment to individual, supermassive, binary black hole systems. © 2009 The Authors. Journal compilation © 2009 RAS.

Detecting A Stochastic Gravitational-Wave Background: The Overlap Reduction Function, Lee Samuel Finn, Shane L. Larson, Joseph D. Romano

Physics and Astronomy Faculty Publications and Presentations

Detection of a gravitational-wave stochastic background via ground or space-based gravitational-wave detectors requires the cross correlation of the response of two or more independent detectors. The cross correlation involves a frequency-dependent factor—the so-called overlap reduction function or HellingsDowns curve—that depends on the relative geometry of each detector pair, i.e., the detector separations and the relative orientation of their antenna patterns (beams). An incorrect formulation of this geometrical factor has appeared in the literature, leading to incorrect conclusions regarding the sensitivity of proposed detectors to a stochastic gravitational-wave background. To rectify these errors and as a reference for future work we …

Pulsar Timing And Spacetime Curvature, Teviet Creighton, F. A. Jenet, Richard H. Price

Physics and Astronomy Faculty Publications and Presentations

We analyze the effect of weak field gravitational waves on the timing of pulsars, with particular attention to gauge invariance, that is, to the effects that are independent of the choice of coordinates. We find (1) the Doppler shift cannot be separated into gauge invariant gravitational wave and kinetic contributions; (2) a gauge invariant separation can be made for the time derivative of the Doppler shift in which the gravitational wave contribution is directly related to the Riemann tensor, and the kinetic contribution is that for special relativity; (3) the gaugedependent effects in the Doppler shift play no role in …

The Contribution Of Halo White Dwarf Binaries To The Laser Interferometer Space Antenna Signal, Ashley J. Ruiter, Krzysztof Belczynski, Matthew Benacquista, Kelly Holley-Bockelmann

Physics and Astronomy Faculty Publications and Presentations

Galactic double white dwarfs were postulated as a source of confusion limited noise for the Laser Interferometer Space Antenna (LISA), the future space-based gravitational wave observatory. Until very recently, the Galactic population consisted of a relatively well-studied disk population, a somewhat studied smaller bulge population and a mostly unknown, but potentially large halo population. It has been argued that the halo population may produce a signal that is much stronger (factor of ∼5 in spectral amplitude) than the disk population. However, this surprising result was not based on an actual calculation of a halo white dwarf population, but was derived …

All-Sky Ligo Search For Periodic Gravitational Waves In The Early Fifth-Science-Run Data, B. P. Abbott, R. Abbott, Matthew Benacquista, Teviet Creighton, Mario C. Diaz, R. Grosso, K. Hayama, Soumya Mohanty, Soma Mukherjee, Malik Rakhmanov, Joseph D. Romano

Physics and Astronomy Faculty Publications and Presentations

We report on an all-sky search with the LIGO detectors for periodic gravitational waves in the frequency range 50–1100 Hz and with the frequency’s time derivative in the range −5×10−9–0  Hz s−1. Data from the first eight months of the fifth LIGO science run (S5) have been used in this search, which is based on a semicoherent method (PowerFlux) of summing strain power. Observing no evidence of periodic gravitational radiation, we report 95% confidence-level upper limits on radiation emitted by any unknown isolated rotating neutron stars within the search range. Strain limits below 10−24 are obtained over a 200-Hz band, …

Gec1-Kappa Opioid Receptor Binding Involves Hydrophobic Interactions Gec1 Has Chaperone-Like Effect, Yong Chen, Chongguang Chen, Evangelia Kotsikorou, Diane L. Lynch, Patricia H. Reggio, Lee Yuan Liu-Chen

Chemistry Faculty Publications and Presentations

We demonstrated previously that the protein GEC1 (glandular epithelial cell 1) bound to the human κ opioid receptor (hKOPR) and promoted cell surface expression of the receptor by facilitating its trafficking along the secretory pathway. Here we showed that three hKOPR residues (Phe³⁴⁵, Pro³⁴⁶, and Met³⁵⁰) and seven GEC1 residues (Tyr⁴⁹, Val⁵¹, Leu⁵⁵, Thr⁵⁶, Val⁵⁷, Phe⁶⁰, and Ile⁶⁴) are indispensable for the interaction. Modeling studies revealed that the interaction was mediated via direct contacts between the kinked hydrophobic fragment in …

Einstein@Home Search For Periodic Gravitational Waves In Ligo S4 Data, B. Abbott, R. Abbott, R. Adhikari, P. Ajith, B. Allen, G. Allen, R. Amin, D. P. Anderson, S. B. Anderson, W. G. Anderson, M. A. Arain, M. Araya, H. Armandula, P. Armor, Y. Aso, S. Aston, P. Aufmuth, C. Aulbert, S. Babak, S. Ballmer, H. Bantilan, B. C. Barish, C. Barker, D. Barker, B. Barr, P. Barriga, M. A. Barton, M. Bastarrika, K. Bayer, J. Betzwieser

Physics and Astronomy Faculty Publications and Presentations

A search for periodic gravitational waves, from sources such as isolated rapidly spinning neutron stars, was carried out using 510 h of data from the fourth LIGO science run (S4). The search was for quasimonochromatic waves in the frequency range from 50 to 1500 Hz, with a linear frequency drift ḟ (measured at the solar system barycenter) in the range -f/τ<ḟ<0. 1f/τ, where the minimum spin-down age τ was 1000 yr for signals below 300 Hz and 10000 yr above 300 Hz. The main computational work of the search was distributed over approximately 100000 computers volunteered by the general public. This large computing power allowed the use of a relatively long coherent integration time of 30 h, despite the large parameter space searched. No statistically significant signals were found. The sensitivity of the search is estimated, along with the fraction of parameter space that was vetoed because of contamination by instrumental artifacts. In the 100 to 200 Hz band, more than 90% of sources with dimensionless gravitational-wave strain amplitude greater than 10-23 would have been detected. © 2009 The American Physical Society.

Highly Stereoselective B-Lactam Synthesis Via The Staudinger Reaction Using Poly Aromatic Imines, Debasish Bandyopadhyay, Monica Xavier, Bimal K. Banik

Chemistry Faculty Publications and Presentations

Highly stereoselective synthesis of a few trans 3-phthalimido substituted B-lactams has been achieved following Staudinger reaction.

The Informational Content Of Canonical Disjoint Np-Pairs, Christian Glaßer, Alan L. Selman, Liyu Zhang

Computer Science Faculty Publications and Presentations

We investigate the connection between propositional proof systems and their canonical pairs. It is known that simulations between propositional proof systems translate to reductions between their canonical pairs. We focus on the opposite direction and study the following questions.

Q1: For which propositional proof systems f and g does the implication hold, and for which does it fail?

Q2: For which propositional proof systems of different strengths are the canonical pairs equivalent?

Q3: What do (non-)equivalent canonical pairs tell about the corresponding propositional proof systems?

Q4: Is every NP-pair (A, B), where A is NP-complete, strongly many-one equivalent to the …

Arecibo Pulsar Survey Using Alpha: Probing Radio Pulsar Intermittency And Transients, J. S. Deneva, J. M. Cordes, M. A. Mclaughlin, D. J. Nice, D. R. Lorimer, F. Crawford, N. D.R. Bhat, F. Camilo, D. J. Champion, P. C.C. Freire, S. Edel, V. I. Kondratiev, J. W.T. Hessels, F. A. Jenet, L. Kasian, V. M. Kaspi, M. Kramer, P. Lazarus, S. M. Ransom, I. H. Stairs, B. W. Stappers, J. Van Leeuwen, A. Brazier, A. Venkataraman, J. A. Zollweg, S. Bogdanov

Physics and Astronomy Faculty Publications and Presentations

We present radio transient search algorithms, results, and statistics from the ongoing Arecibo Pulsar ALFA (PALFA) survey of the Galactic plane. We have discovered seven objects through a search for isolated dispersed pulses. All of these objects are Galactic and have measured periods between 0.4 and 4.7 s. One of the new discoveries has a duty cycle of 0.01%, smaller than that of any other radio pulsar. We discuss the impact of selection effects on the detectability and classification of intermittent sources, and compare the efficiencies of periodicity and single-pulse (SP) searches for various pulsar classes. For some cases we …

Strong Field Effects On Pulsar Arrival Times: Circular Orbits And Equatorial Beams, Yan Wang, F. A. Jenet, Teviet Creighton, Richard H. Price

Physics and Astronomy Faculty Publications and Presentations

If a pulsar orbits a supermassive black hole, the timing of pulses that pass close to the hole will show a variety of strong field effects. To compute the intensity and timing of pulses that have passed close to a nonrotating black hole, we introduce here a simple formalism based on two \"universal functions,\" one for the bending of photon trajectories and the other for the photon travel time on these trajectories. We apply this simple formalism to the case of a pulsar in circular orbit that beams its pulses into the orbital plane. In addition to the \"primary\" pulses …

Probabilistic Analysis Of A Motif Discovery Algorithm For Multiple Sequences, Bin Fu, Ming-Yang Kao, Lusheng Wang

Computer Science Faculty Publications and Presentations

We study a natural probabilistic model for motif discovery that has been used to experimentally test the quality of motif discovery programs. In this model, there are k background sequences, and each character in a background sequence is a random character from an alphabet Σ. A motif G = g1g2 · · · gm is a string of m characters. Each background sequence is implanted into a probabilistically generated approximate copy of G. For an approximate copy b1b2 · · · bm of G, every character bi is probabilistically generated such that the probability for r $b_i\neq g_i$ is at …

Strong Field Effects On Pulsar Arrival Times: General Orientations, Yan Wang, Teviet Creighton, Richard H. Price, Fredrick A. Jenet

Physics and Astronomy Faculty Publications and Presentations

A pulsar beam passing close to a black hole can provide a probe of very strong gravitational fields even if the pulsar itself is not in a strong field region. In the case that the spin of the hole can be ignored, we have previously shown that all strong field effects on the beam can be understood in terms of two \"universal\" functions: F(φin) and T(φin) of the angle of beam emission φin; these functions are universal in that they depend only on a single parameter, the pulsar/black hole distance from which the beam is emitted. Here we apply this …

Search For Gravitational Waves From Low Mass Binary Coalescences In The First Year Of Ligo’S S5 Data, B. P. Abbott, R. Abbott, Matthew Benacquista, Teviet Creighton, Mario C. Diaz, R. Grosso, K. Hayama, H. Lei, Soumya Mohanty, Soma Mukherjee, Malik Rakhmanov, Joseph D. Romano, Robert Stone, Lappoon R. Tang

Physics and Astronomy Faculty Publications and Presentations

We have searched for gravitational waves from coalescing low mass compact binary systems with a total mass between 2M⊙ and 35M⊙ and a minimum component mass of 1M⊙ using data from the first year of the fifth science run of the three LIGO detectors, operating at design sensitivity. Depending on the mass, we are sensitive to coalescences as far as 150 Mpc from the Earth. No gravitational-wave signals were observed above the expected background. Assuming a population of compact binary objects with a Gaussian mass distribution representing binary neutron star systems, black hole–neutron star binary systems, and binary black hole …

Stellar Population Models And Individual Element Abundances. Ii. Stellar Spectra And Integrated Light Models, Hyun Chul Lee, Guy Worthey, Aaron Dotter, Brian Chaboyer, Darko Jevremović, E. Baron, Michael M. Briley, Jason W. Ferguson, Paula Coelho, Scott C. Trager

Physics and Astronomy Faculty Publications and Presentations

The first paper in this series explored the effects of altering the chemical mixture of the stellar population on an element-by-element basis on stellar evolutionary tracks and isochrones to the end of the red giant branch. This paper extends the discussion by incorporating the fully consistent synthetic stellar spectra with those isochrone models in predicting integrated colors, Lick indices, and synthetic spectra. Older populations display element ratio effects in their spectra at higher amplitude than younger populations. In addition, spectral effects in the photospheres of stars tend to dominate over effects from isochrone temperatures and lifetimes, but, further, the isochrone-based …

First Ligo Search For Gravitational Wave Bursts From Cosmic (Super)Strings, B. P. Abbott, R. Abbott, Matthew Benacquista, Teviet Creighton, Mario C. Diaz, R. Grosso, K. Hayama, H. Lei, Soumya Mohanty, Soma Mukherjee, Malik Rakhmanov, Joseph D. Romano, Robert Stone, Lappoon R. Tang

Physics and Astronomy Faculty Publications and Presentations

No abstract provided.

Search For Gravitational Waves From Low Mass Compact Binary Coalescence In 186 Days Of Ligo’S Fifth Science Run, B. P. Abbott, R. Abbott, Matthew Benacquista, Teviet Creighton, K. Hayama, H. Lei, Soumya Mohanty, Soma Mukherjee, Malik Rakhmanov, Joseph D. Romano, Robert Stone, Lappoon R. Tang

Physics and Astronomy Faculty Publications and Presentations

We report on a search for gravitational waves from coalescing compact binaries, of total mass between 2 and 35M⊙, using LIGO observations between November 14, 2006 and May 18, 2007. No gravitational-wave signals were detected. We report upper limits on the rate of compact binary coalescence as a function of total mass. The LIGO cumulative 90%-confidence rate upper limits of the binary coalescence of neutron stars, black holes and black hole-neutron star systems are 1.4×10−2, 7.3×10−4 and 3.6×10−3  yr−1 L−110, respectively, where L10 is 1010 times the blue solar luminosity.

Stacked Search For Gravitational Waves From The 2006 Sgr 1900+14 Storm, B. P. Abbott, R. Abbott, R. Adhikari, P. Ajith, B. Allen, G. Allen, R. S. Amin, S. B. Anderson, W. G. Anderson, M. A. Arain, M. Araya, H. Armandula, P. Armor, Y. Aso, S. Aston, P. Aufmuth, C. Aulbert, S. Babak, P. Baker, S. Ballmer, C. Barker, D. Barker, B. Barr, P. Barriga, L. Barsotti, M. A. Barton, I. Bartos, R. Bassiri, M. Bastarrika, B. Behnke

Physics and Astronomy Faculty Publications and Presentations

We present the results of a LIGO search for short-duration gravitational waves (GWs) associated with the 2006 March 29 SGR 1900+14 storm. A new search method is used, \"stacking\" the GW data around the times of individual soft-gamma bursts in the storm to enhance sensitivity for models in which multiple bursts are accompanied by GW emission. We assume that variation in the time difference between burst electromagnetic emission and potential burst GW emission is small relative to the GW signal duration, and we time-align GW excess power time-frequency tilings containing individual burst triggers to their corresponding electromagnetic emissions. We use …

Xafs Debye-Waller Factors For Deformed Hemes And Metal Substituted Hemes, N. Dimakis, T. Mion, C. Ramirez, G. Bunker

Physics and Astronomy Faculty Publications and Presentations

We present an efficient and accurate method for calculating XAFS Debye-Waller factors for deformed active sites of hemoproteins and metal substituted hemes. Based on the Normal Coordinate Structural Decomposition scheme, the deformation of the porphyrin macrocycle is expressed as a linear combination of the normal modes of the planar species. In our approach, we identify the modes that contribute most to the deformation. Small metal-porphyrin structures which match the macrocycle structural deformation of the deformed hemoprotein site are used to calculate the Debye-Waller parameters at sample's temperature. The Debye-Waller factors are directly obtained by calculating the normal mode spectrum of …

Search For Gravitational-Wave Bursts In The First Year Of The Fifth Ligo Science Run, B. P. Abbott, R. Abbott, Matthew Benacquista, Teviet Creighton, Mario C. Diaz, R. Grosso, K. Hayama, Hansheng Lei, Soumya Mohanty, S. Mukherjee, Malik Rakhmanov, Joseph D. Romano, Robert Stone, Lappoon R. Tang

Physics and Astronomy Faculty Publications and Presentations

We present the results obtained from an all-sky search for gravitational-wave (GW) bursts in the 64–2000 Hz frequency range in data collected by the LIGO detectors during the first year (November 2005—November 2006) of their fifth science run. The total analyzed live time was 268.6 days. Multiple hierarchical data analysis methods were invoked in this search. The overall sensitivity expressed in terms of the root-sum-square (rss) strain amplitude hrss for gravitational-wave bursts with various morphologies was in the range of 6×10−22  Hz−1/2 to a few×10−21  Hz−1/2. No GW signals were observed and a frequentist upper limit of 3.75 events per …

Structure Of Polc Reveals Unique Dna Binding And Fidelity Determinants, Ronald J. Evans, Douglas R. Davies, James M. Bullard, Jeffrey Christensen, Louis S. Green, Joseph W. Guiles, Janice D. Pata, Wendy K. Ribble, Nebojsa Janjic, Thale C. Jarvis

Chemistry Faculty Publications and Presentations

PolC is the polymerase responsible for genome duplication in many Gram-positive bacteria and represents an attractive target for antibacterial development. We have determined the 2.4-Å resolution crystal structure of Geobacillus kaustophilus PolC in a ternary complex with DNA and dGTP. The structure reveals nascent base pair interactions that lead to highly accurate nucleotide incorporation. A unique β-strand motif in the PolC thumb domain contacts the minor groove, allowing replication errors to be sensed up to 8 nt upstream of the active site. PolC exhibits the potential for large-scale conformational flexibility, which could encompass the catalytic residues. The structure suggests a …

Locality And Stability Of The Cascades Of Two-Dimensional Turbulence, Eleftherios Gkioulekas

School of Mathematical and Statistical Sciences Faculty Publications and Presentations

We investigate and clarify the notion of locality as it pertains to the cascades of two-dimensional turbulence. The mathematical framework underlying our analysis is the infinite system of balance equations that govern the generalized unfused structure functions, first introduced by L’vov and Procaccia. As a point of departure we use a revised version of the system of hypotheses that was proposed by Frisch for three-dimensional turbulence. We show that both the enstrophy cascade and the inverse energy cascade are local in the sense of nonperturbative statistical locality. We also investigate the stability conditions for both cascades. We have shown that …

Uv-Vis Investigations On Ion Beam Irradiated Polycarbonate, Mircea Chipara, Dorina M. Chipara

Physics and Astronomy Faculty Publications and Presentations

UV-VIS investigations on polycarbonate irradiated with accelerated U ions are reported. The experimental data are consistent with the decrease of the energy gap due to irradiation and indicate the formation of isolated conjugated structures. The relatively weak decrease of the energy gap and the shape of the electron spin resonance lines indicate that the conjugated structures are isolated within the polymeric matrix. published: 8 November, 2008.