Synthesis And Characterization Of Zinc-‐Oxide/Polystyrene Nanocomposite Thin Films,
2014
Macalester College
Synthesis And Characterization Of Zinc-‐Oxide/Polystyrene Nanocomposite Thin Films, Christopher Krapu
Macalester Journal of Physics and Astronomy
Ultra-thin films containing zinc oxide and polystyrene were prepared by sol-gel mixing and spincoating onto silicon substrate. Photoluminescent measurements were recorded following irradiation at 325 nm. We observed passivation of shallow defect states around 3.1 eV bandgap via confinement. Time-resolved photoluminescence plots suggest a significant time dependence of emission intensity related to photodegradation of the polymer matrix.
Light-By-Light Scattering Nonlogarithmic Corrections To Hyperfine Splitting In Muonium,
2014
University of Kentucky
Light-By-Light Scattering Nonlogarithmic Corrections To Hyperfine Splitting In Muonium, Michael I. Eides, Valery A. Shelyuto
Physics and Astronomy Faculty Publications
We consider three-loop corrections to hyperfine splitting in muonium generated by the gauge invariant set of diagrams with a virtual light-by-light scattering block. These diagrams produce both recoil and nonrecoil contributions to hyperfine splitting. Recoil corrections are enhanced by large logarithms of the muon-electron mass ratio. Both nonrecoil and logarithmically enhanced radiative-recoil corrections were calculated some time ago. Here we calculate nonlogarithmic radiative-recoil corrections generated by the insertions of the light-by-light scattering block.
Extensive Study Of Hd 25558, A Long-Period Double-Lined Binary With Two Spb Components,
2014
Royal Observatory of Belgium
Extensive Study Of Hd 25558, A Long-Period Double-Lined Binary With Two Spb Components, Á. Sódor, Peter De Cat, David J. Wright, Coralie Neiner, Maryline Briquet, Patricia Lampens, Robert J. Dukes, Gregory W. Henry, Michael H. Williamson, Emily Brunsden, Karen R. Pollard, Peter L. Cottrell, Florian Maisonneuve, Pam M. Kilmartin, Jaymie Matthews, Thomas Kallinger, Paul G. Beck, Eiji Kambe, Chris A. Engelbrecht, Robert J. Czanik, Stephenson Yang, Osamu Hashimoto, Satoshi Honda, Jian-Ning Fu, Barbara Castanheira, Holger Lehmann, Zsófia Bognár, Natalie Behara, Simone Scaringi, Hans Van Winckel, Jonathan Menu, Alex Lobel, P. Mathias, Sophie Saesen, Maja Vučković, The Mimes Collaboration
Information Systems and Engineering Management Research Publications
We carried out an extensive observational study of the Slowly Pulsating B (SPB) star, HD 25558. The ≈2000 spectra obtained at different observatories, the ground-based and MOST satellite light curves revealed that this object is a double-lined spectroscopic binary with an orbital period of about nine years. The observations do not allow the inference of an orbital solution. We determined the physical parameters of the components, and found that both lie within the SPB instability strip. Accordingly, both show line-profile variations due to stellar pulsations. 11 independent frequencies were identified in the data. All the frequencies were attributed to one …
Variability In Quasars,
2014
Brigham Young University
Variability In Quasars, Catherine Morris, Dr. Eric Hintz
Journal of Undergraduate Research
This project looked for variability in quasars 3C273 and Mark 509. Between May 2003 and July 2003 several nights of data were taken on these quasars. The project was also to see if “good” data on quasars could be obtained using the BYU 16” telescope, since not much research has been done on this topic at BYU. Over the summer data were also taken on various other quasars whose brightness ranged between 12 and 14.
Constructing The Remote Observatory For Variable Object Research,
2014
Brigham Young University
Constructing The Remote Observatory For Variable Object Research, Jason A. Gilbert, Dr. J. Ward Moody
Journal of Undergraduate Research
Scientists who attempt to unravel the mysteries of the universe have some physical limitations to deal with in their quest. For example, an observer must stay up all night to operate the telescopes that record the data. There are now automated telescopes that allow the scientist to enter a list of objects (stars, asteroids, planets, galaxies, etc.) into the telescope’s computer, and the telescope will move by itself to each one, taking and recording data throughout the course of the night. Some telescopes can even be operated remotely so the scientists can run them from their offices, or even their …
Growth Kinetics Of Zno By Magnetron Sputtering For Solar Cell Application,
2014
Macalester College
Growth Kinetics Of Zno By Magnetron Sputtering For Solar Cell Application, Nadia Foo Kune
Macalester Journal of Physics and Astronomy
The goal of this work is study the mechanism of ZnO thin film deposition by rf magnetron sputtering with an argon plasma. This research will help understand the growth kinetics of the ZnO layer in relation to the growth conditions for solar cell application. We study the rate of growth, the electrical properties, the optical transmission and the zinc to oxygen ratio of each sample as a function of growth temperature. We conclude that Zn evaporation competes with incorporation into the film by combining with an arriving O atom.
Tip-Of-The-Red-Giant-Branch Detection: Estimating The Distance To Resolved Galaxies In Shield,
2014
Macalester College
Tip-Of-The-Red-Giant-Branch Detection: Estimating The Distance To Resolved Galaxies In Shield, Ian Cave
Macalester Journal of Physics and Astronomy
The Survey of HI in Extremely Low-mass Dwarfs (SHIELD) is an ongoing study of twelve galaxies with HI masses between 106 and 107 Solar masses, detected by the Arecibo Legacy Fast ALFA (ALFALFA) survey. One of the important characteristics of a galaxy is its distance, since knowing that value allows us to calibrate many other factors and learn more about the galaxy. This research was focused on creating a program to systematically solve for the distance to the galaxies in SHIELD. To perform this calculation, Tip-of-the-Red-Giant-Branch (TRGB) detection was chosen, which is a popular method for galaxies with …
Electrical Conductivity Of Tellurium Nanowires On Pedot:Pss,
2014
Macalester College
Electrical Conductivity Of Tellurium Nanowires On Pedot:Pss, Banteaymolu Alebachew
Macalester Journal of Physics and Astronomy
The purpose of this project is to understand the electrical conductivity and infrared absorption spectrum of a hybrid material between Tellurium nanowires and a carbon polymer called PEDOT:PSS. This hybrid material shows much higher conductivity than its components and this behavior gives a great promise for thermoelectric effect. The most intriguing property of this material is observed when taking absorption spectrum from far to near infrared. The hybrid material shows a much bigger absorption edge than Te NW. This project attempts to explain this shift using the confinement energy model and Fermi blocking (due to doping). The result from these …
Sub-Sonic Open-Return Wind-Tunnel And Measurement Apparatus,
2014
Macalester College
Sub-Sonic Open-Return Wind-Tunnel And Measurement Apparatus, Michael Adams
Macalester Journal of Physics and Astronomy
Wind tunnels are an effective tool for understanding relationships between predicted and actual behavior of air foils in laminar flow. In order to improve the ability of Macalester College staff and students to observe and experiment with the effects of laminar air flow on various objects and systems, it was necessary to construct and test a sub-sonic open return wind tunnel. The purpose of the tests was to discover whether or not the air flow through the test section of the tunnel was laminar around the object being tested and also to evaluate the quality of an apparatus constructed to …
Energy Dependence Of Moments Of Net-Proton Multiplicity Distributions At Rhic,
2014
University of Kentucky
Energy Dependence Of Moments Of Net-Proton Multiplicity Distributions At Rhic, James K. Atkins, Renee H. Fatemi, Wolfgang Korsch, Suvarna Ramachandran, G. Webb, L. Adamczyk, G. Agakishiev, M. M. Aggarwal, Z. Ahammed, I. Alekseev, J. Alford, C. D. Anson, A. Aparin, D. Arkhipkin, E. C. Aschenauer, G. S. Averichev, J. Balewski, A. Banerjee, Z. Barnovska, D. R. Beavis, R. Bellwied, A. Bhasin, A. K. Bhati, P. Bhattarai, H. Bichsel, J. Bielcik, J. Bielcikova, L. C. Bland, I. G. Bordyuzhin, W. Borowski
Physics and Astronomy Faculty Publications
We report the beam energy(√8NN = 7.7-200 GeV) and collision centrality dependence of the mean (M), standard deviation (σ), skewness (S), and kurtosis (κ) of the net-proton multiplicity distributions in Au+Au collisions. The measurements are carried out by the STAR experiment at midrapidity (|y|<0.5) and within the transverse momentum range 0.4<ρτ<0.8 GeV/c in the first phase of the Beam Energy Scan program at the Relativistic Heavy Ion Collider. These measurements are important for understanding the quantum chromodynamic phase diagram. The products of the moments, Sσ and κσ2, are sensitive to the correlation length of the hot and dense …
Interpreting The Ionization Sequence In Agn Emission-Line Spectra,
2014
Michigan State University
Interpreting The Ionization Sequence In Agn Emission-Line Spectra, Chris T. Richardson, James T. Allen, Jack A. Baldwin, Paul C. Hewett, Gary J. Ferland
Physics and Astronomy Faculty Publications
We investigate the physical cause of the great range in the ionization level seen in the spectra of narrow-lined active galactic nuclei (AGN). We used a recently developed technique called mean field independent component analysis to identify examples of individual Sloan Digital Sky Survey galaxies whose spectra are not dominated by emission due to star formation (SF), which we therefore designate as AGN. We assembled high signal-to-noise ratio (S/N) composite spectra of a sequence of these AGN defined by the ionization level of their narrow-line regions (NLR), and extending down to very low ionization cases. We then used a local …
Black Hole Variability And The Star Formation-Active Galactic Nucleus Connection: Do All Star-Forming Galaxies Host An Active Galactic Nucleus?,
2014
Dartmouth College
Black Hole Variability And The Star Formation-Active Galactic Nucleus Connection: Do All Star-Forming Galaxies Host An Active Galactic Nucleus?, Ryan C. Hickox, James R. Mullaney, David M. Alexander, Chien-Ting J. Chen, Francesca M. Civano, Andy D. Goulding, Kevin N. Hainline
Dartmouth Scholarship
We investigate the effect of active galactic nucleus (AGN) variability on the observed connection between star formation and black hole accretion in extragalactic surveys. Recent studies have reported relatively weak correlations between observed AGN luminosities and the properties of AGN hosts, which has been interpreted to imply that there is no direct connection between AGN activity and star formation. However, AGNs may be expected to vary significantly on a wide range of timescales (from hours to Myr) that are far shorter than the typical timescale for star formation (100 Myr). This variability can have important consequences for observed correlations. We …
Self-Heating Model Of Spherical Aluminum Nanoparticle Oxidation,
2014
The University of Texas Rio Grande Valley
Self-Heating Model Of Spherical Aluminum Nanoparticle Oxidation, Karen S. Martirosyan, Zamart Ramazanova, Maxim Zyskin
Physics & Astronomy Faculty Publications
Aluminum-oxygen reaction is important in highly energetic and high pressure generating systems. Nanoenergetic thermites include mixtures of nanostructured Al and oxidizer particles. The main distinguishing features of these reactive systems are their significant enthalpy release and tunable rate of energy discharge, which gives rise to a wide range of combustion rates, energy release, and ignition sensitivity. In this paper, we consider rapid oxidation of a spherically symmetric aluminum particle. We use the Cabrera Mott oxidation model to describe the kinetics of oxide growth of an aluminum nanoparticle and to predict reaction temperature and oxidation time. We assume that aluminum particle …
Neutral Pion Cross Section And Spin Asymmetries At Intermediate Pseudorapidity In Polarized Proton Collisions At √S=200 Gev,
2014
AGH University of Science and Technology, Poland
Neutral Pion Cross Section And Spin Asymmetries At Intermediate Pseudorapidity In Polarized Proton Collisions At √S=200 Gev, L. Adamczyk, James K. Adkins, G. Agakishiev, M. M. Aggarwal, Z. Ahammed, I. Alekseev, J. Alford, C. D. Anson, A. Aparin, D. Arkhipkin, Renee H. Fatemi, Robert G. Fersch, Wolfgang Korsch, Suvarna Ramachandran, G. Webb
Physics and Astronomy Faculty Publications
The differential cross section and spin asymmetries for neutral pions produced within the intermediate pseudorapidity range 0.8<ηpT/c and is found to agree with a next-to-leading order perturbative QCD calculation. The longitudinal double-spin asymmetry ALL is measured in the same pseudorapidity range and spans a range of Bjorken-x down to x≈0.01. The measured ALL is consistent with model predictions for varying degrees of gluon polarization. The parity-violating asymmetry AL is also measured and found to be consistent with zero. The transverse single-spin asymmetry AN is measured over a previously unexplored kinematic range in …
Long-Term Tev And X-Ray Observations Of The Gamma- Ray Binary Hess J0632+057,
2014
Cork Institute of Technology
Long-Term Tev And X-Ray Observations Of The Gamma- Ray Binary Hess J0632+057, P. T. Reynolds, Veritas, Hess
Physical Sciences Publications
HESS J0632+057 is the only gamma-ray binary known so far whose position in the sky allows observations with ground-based observatories in both the northern and southern hemispheres. Here we report on long-term observations of HESS J0632+057 conducted with the Very Energetic Radiation Imaging Telescope Array System and High Energy Stereoscopic System Cherenkov telescopes and the X-ray satellite Swift, spanning a time range from 2004 to 2012 and covering most of the system's orbit. The very-high-energy (VHE) emission is found to be variable and is correlated with that at X-ray energies. An orbital period of days is derived from the …
Energy Dependence Of The (E,2E) Recoil Peak To Binary Peak Ratio Across He (2P2)1D And (2S2P)1P Autoionizing Levels,
2014
Illinois Wesleyan University
Energy Dependence Of The (E,2E) Recoil Peak To Binary Peak Ratio Across He (2P2)1D And (2S2P)1P Autoionizing Levels, B. A. Deharak, K. Bartschat, Nicholas L. S. Martin
Physics and Astronomy Faculty Publications
The (e,2e) recoil peak to binary peak ratio as a function of the ejected-electron energy is reported for helium autoionizing levels (2p2)1D and (2s2p)1P. A special out-of-plane geometry is used where the ejected electrons are detected in a plane that includes the momentum transfer axis but is perpendicular to the scattering plane. The measured recoil peak to binary peak ratio is a dimensionless quantity that can be directly compared with calculations. A second-order model in the projectile-target interaction correctly reproduces the observed energy dependence …
Annual Solar Motion And Spy Satellites,
2014
Utah State University
Annual Solar Motion And Spy Satellites, Margaret Jensen, Shane L. Larson
Browse All Undergraduate research
A topic often taught in introductory astronomy courses is the changing position of the Sun in the sky as a function of time of day, and season. The relevance and importance of this motion is explained in the context of seasons and the impact it has on human activities such as agriculture. The geometry of the ob- served motion in the sky is usually reduced to graphical representations and visualizations that can be difficult to render and grasp. Sometimes students are asked to observe the Suns changing motion and record their data, but this is a long-term project requiring several …
Updating And Revising Star Camera For Future Flights Of Balloon Borne Experiment,
2014
California State University - Sacramento
Updating And Revising Star Camera For Future Flights Of Balloon Borne Experiment, Krystle N. Sy, Seth Hillbrand
STAR Program Research Presentations
The BLAST (Balloon-borne Large Aperture Submillimeter Telescope) experiment surveys the galaxy from altitudes of 100,000 ft in order to answer important cosmological questions, such as how stars are formed. This experiment is conducted above Antarctica to minimize unwanted noise. Two star cameras are used in the navigation systems to identify known stars. The cameras take pictures and match stars in the image to known star positions from a catalog stored in the star camera's computer. This is done using code written in C++, a computer programming language. In order to modernize the system, the code needs to be updated. A …
Probing The Alfvén Speed Profile Using Type Ii Radio Bursts,
2014
Central Coast New Tech High
Probing The Alfvén Speed Profile Using Type Ii Radio Bursts, Peter Sullivan, Hazel M. Bain
STAR Program Research Presentations
Type II radio bursts can be produced when a coronal mass ejection (CME) traveling faster than the local plasma speed of the ambient medium produces a shock. From the drift rate of type II bursts it is possible to calculate the velocity of the CME. We present a statistical survey of type II radio burst events during 2012-2013. Using radio observations we determine speeds of CME shocks as a means of setting limits on the Alfvén speed profile of the interplanetary medium as a function of distance from the sun. In particular we use observations from the WAVES instruments onboard …
Landsat-8: Science And Product Vision For Terrestrial Global
Change Research,
2014
South Dakota State University
Landsat-8: Science And Product Vision For Terrestrial Global Change Research, David P. Roy, M. A. Wulder, T. R. Loveland, C. E. Woodcock, R. G. Allen, M. C. Anderson, D. Helder, J. R. Irons, D. M. Johnson, R. Kennedy, T. A. Scambos, C. B. Schaaf, J. R. Schott, Y. Sheng, E. F. Vermote, A. S. Belward, R. Bindschadler, W. B. Cohen, F. Gao, J. D. Hipple, P. Hostert, Desert Research Institute, Reno, Nv, C. O. Justice, Ayse Kilic, V. Kovalskyy, Z. P. Lee, L. Lymburner, J. G. Masek, J. Mccorkel, Y. Shuai, R. Trezza, J. Vogelmann, R. H. Wynne, Z. Zhu
School of Natural Resources: Faculty Publications
Landsat 8, a NASA and USGS collaboration, acquires global moderate-resolution measurements of the Earth's terrestrial and polar regions in the visible, near-infrared, short wave, and thermal infrared. Landsat 8 extends the remarkable 40 year Landsat record and has enhanced capabilities including new spectral bands in the blue and cirrus cloud-detection portion of the spectrum, two thermal bands, improved sensor signal-to-noise performance and associated improvements in radiometric resolution, and an improved duty cycle that allows collection of a significantly greater number of images per day. This paper introduces the current (2012–2017) Landsat Science Team's efforts to establish an initial understanding of …
