Open Access. Powered by Scholars. Published by Universities.®

Physical Sciences and Mathematics Commons

Open Access. Powered by Scholars. Published by Universities.®

292,320 Full-Text Articles 381,128 Authors 94,606,419 Downloads 464 Institutions

All Articles in Physical Sciences and Mathematics

Faceted Search

292,320 full-text articles. Page 9660 of 9702.

Observations Of Prolific Transient Luminous Event Production Above A Mesoscale Convective System In Argentina During The Sprite2006 Campaign In Brazil, F. T. São Sabbas, Michael J. Taylor, Pierre-Dominique Pautet, T. Berkey, S. Cummer, R. R. Azambuja, J. P.C. Santiago, J. N. Thomas, O. Pinto Jr., N. N. Solorzano, N. J. Schuch, S. R. Freitas, N. J. Ferreira, J. C. Conforte 2010 Utah State University

Observations Of Prolific Transient Luminous Event Production Above A Mesoscale Convective System In Argentina During The Sprite2006 Campaign In Brazil, F. T. São Sabbas, Michael J. Taylor, Pierre-Dominique Pautet, T. Berkey, S. Cummer, R. R. Azambuja, J. P.C. Santiago, J. N. Thomas, O. Pinto Jr., N. N. Solorzano, N. J. Schuch, S. R. Freitas, N. J. Ferreira, J. C. Conforte

All Physics Faculty Publications

On the night of 22–23 February 2006, 444 transient luminous events (TLEs), 86% sprites, were observed above a prolific mesoscale convective system (MCS) over Argentina, as part of the third sprite campaign in Brazil. GOES infrared (IR) cloud top temperatures (Tc) and Tropical Rainfall Measuring Mission (TRMM) radar (PR) and microwave (TMI) data were used to investigate the MCS convective characteristics and their relationship with World Wide Location Network (WWLLN) detected cloud‐to‐ground (CG) lightning and TLE activity. The MCS had a minimum lifetime of 20 hours, 8.5 as a MCS, a maximum extent of ∼430,000 km2, and gusty winds of …


Charge Dynamics In Highly Insulating Space Craft Materials, Alec Sim, John R. Dennison 2010 Utah State University

Charge Dynamics In Highly Insulating Space Craft Materials, Alec Sim, John R. Dennison

All Physics Faculty Publications

We present a preliminary report on the theoretical and experimental study of transport models in highly insulating materials. The report is developed in four sections; first we give background on the nature of the problems in space craft charging, the contributions and connections made by the Utah State material physics group. Second we discuss the density of states to explore the connections between material composition and the microscopic and macroscopic transport equations. Third from Maxwell’s equations we present an overview of the transport equations. Finally we present preliminary results using experimental data on KaptonTM, the transport equations and relevant expressions …


The Effects Of Surface Modification On Spacecraft Charging Parameters, Amberly Evans, John R. Dennison 2010 Utah State University

The Effects Of Surface Modification On Spacecraft Charging Parameters, Amberly Evans, John R. Dennison

All Physics Faculty Publications

Charging of materials by incident radiation is affected by both environmental and physical conditions. Modifying a material’s physical surface will change its reflection, transmission and absorption of the incident radiation which are integrally related to the accumulation of charge and energy deposition in the material. An optical analysis of the effect of surface modification on spacecraft charging parameters on prototypical Kapton HN and Cu samples is presented. Samples were roughened with abrasive compounds ranging from 0.5 to 10 μm in size, comparable to the range of incident wavelengths. They were also contaminated with thin layers of DC 704 diffusion pump …


Absorption And Biotransformation Of Polybrominated Diphenyl Ethers De-71 And De-79 In Chicken (Gallus Gallus), Mallard (Anas Platyrhynchos), American Kestrel (Falco Sparverius) And Black-Crowned Night-Heron (Nycticorax Nycticorax) Eggs, Moira A. McKernan, Barnett A. Rattner, Jeff S. Hatfield, Robert C. Hale, Mary Ann Ottinger 2010 University of Maryland

Absorption And Biotransformation Of Polybrominated Diphenyl Ethers De-71 And De-79 In Chicken (Gallus Gallus), Mallard (Anas Platyrhynchos), American Kestrel (Falco Sparverius) And Black-Crowned Night-Heron (Nycticorax Nycticorax) Eggs, Moira A. Mckernan, Barnett A. Rattner, Jeff S. Hatfield, Robert C. Hale, Mary Ann Ottinger

United States Geological Survey: Staff Publications

We recently reported that air cell administration of penta-brominated diphenyl ether (penta-BDE; DE-71) evokes biochemical and immunologic effects in chicken (Gallus gallus) embryos at very low doses, and impairs pipping (i.e., stage immediately prior to hatching) and hatching success at 1.8 µg g-1 egg (actual dose absorbed) in American kestrels (Falco sparverius). In the present study, absorption of polybrominated diphenyl ether (PBDE) congeners was measured following air cell administration of a penta-BDE mixture (11.1 lg DE-71 g-1 egg) or an octa-brominated diphenyl ether mixture (octa BDE; DE-79; 15.4 lg DE-79 g- …


Methods To Determine Total Electron-Induced Electron Yields Over Broad Range Ofconductive And Nonconductive Materials, Ryan C. Hoffmann, John R. Dennison 2010 Air Force Research Laoratory

Methods To Determine Total Electron-Induced Electron Yields Over Broad Range Ofconductive And Nonconductive Materials, Ryan C. Hoffmann, John R. Dennison

All Physics Faculty Publications

The electron emission properties of a material subject to incident radiation flux are key parameters in determining to what equilibrium charge a spacecraft will established under given environmental conditions. However, there is a complex relation between these emission properties and the charge built up in spacecraft insulators. Complex modeling codes have been developed to predict the potential a spacecraft will adopt as a consequence of its interaction with the space plasma. These require correct models of the electron yields as a function of charge to accurately predict the both the charge build up and the equilibrium potential of spacecraft components. …


Unified Model Of Charge Transport In Insulating Polymeric Materials, Alec Sim, John R. Dennison 2010 Utah State University

Unified Model Of Charge Transport In Insulating Polymeric Materials, Alec Sim, John R. Dennison

All Physics Faculty Publications

We present a preliminary report on the theoretical and experimental study of transport models in highly insulating materials. The report is developed in four sections; first we give background on the nature of the problems in space craft charging, the contributions and connections made by the Utah State material physics group. Second we discuss the density of states to explore the connections between material composition and the microscopic and macroscopic transport equations. Third from Maxwell’s equations we present an overview of the transport equations. Finally we present preliminary results using experimental data on KaptonTM, the transport equations and …


Measurement Methods Of Electron Emission Over A Full Range Of Sample Charging, R. C. Hoffman, John R. Dennison 2010 Utah State University

Measurement Methods Of Electron Emission Over A Full Range Of Sample Charging, R. C. Hoffman, John R. Dennison

All Physics Faculty Publications

The electron emission properties of a material subject to incident radiation flux are key parameters in determining to what equilibrium charge a spacecraft will established under given environmental conditions. However, there is a complex relation between these emission properties and the charge built up in spacecraft insulators. Complex modeling codes have been developed to predict the potential a spacecraft will adopt as a consequence of its interaction with the space plasma. These require correct models of the electron yields as a function of charge to accurately predict the both the charge build up and the equilibrium potential of spacecraft components. …


Spacecraft Coating-Induced Charging: A Materials And Modeling Study Of Environmental Extreme, Michelle M. Donegan, Jennifer L. Sample, John R. Dennison, R. Hoffman 2010 Johns Hopkins University

Spacecraft Coating-Induced Charging: A Materials And Modeling Study Of Environmental Extreme, Michelle M. Donegan, Jennifer L. Sample, John R. Dennison, R. Hoffman

All Physics Faculty Publications

As mankind reaches to explore extreme environments in space, the application of ceramics surface coatings is increasing. The 2005 mission concept for Solar Probe used a unique design to achieve the necessary thermal control for a very close approach to the solar corona, including the use of a highly refractory, electrically insulating ceramic coating over a carbon-carbon composite heat shield. The proposed trajectory takes the spacecraft from a Jovian fly-by to within 4 solar radii of the Sun, spanning 5 orders of magnitude in solar radiation and solar wind plasma density as well as spacecraft temperatures from <100 K to >2000 K. Using …


Plasma Treatment Of Bulk Niobium Surface For Superconducting Rf Cavities: Optimization Of The Experimental Conditions On Flat Samples, M. Rašković, J. Upadhyay, L. Vuskovic, S. Popovic, A.-M. Valente-Feliciano, L. Phillips 2010 Old Dominion University

Plasma Treatment Of Bulk Niobium Surface For Superconducting Rf Cavities: Optimization Of The Experimental Conditions On Flat Samples, M. Rašković, J. Upadhyay, L. Vuskovic, S. Popovic, A.-M. Valente-Feliciano, L. Phillips

Physics Faculty Publications

Accelerator performance, in particular the average accelerating field and the cavity quality factor, depends on the physical and chemical characteristics of the superconducting radio-frequency (SRF) cavity surface. Plasma based surface modification provides an excellent opportunity to eliminate nonsuperconductive pollutants in the penetration depth region and to remove the mechanically damaged surface layer, which improves the surface roughness. Here we show that the plasma treatment of bulk niobium (Nb) presents an alternative surface preparation method to the commonly used buffered chemical polishing and electropolishing methods. We have optimized the experimental conditions in the microwave glow discharge system and their influence on …


The Norm Of A Truncated Toeplitz Operator, Stephan Ramon Garcia, William T. Ross 2010 Pomona College

The Norm Of A Truncated Toeplitz Operator, Stephan Ramon Garcia, William T. Ross

Pomona Faculty Publications and Research

We prove several lower bounds for the norm of a truncated Toeplitz operator and obtain a curious relationship between the H2 and Hnorms of functions in model spaces.


Review: Nontangential Limits In Pt(Μ)-Spaces And The Index Of Invariant Subgroups, Stephan Ramon Garcia 2010 Pomona College

Review: Nontangential Limits In Pt(Μ)-Spaces And The Index Of Invariant Subgroups, Stephan Ramon Garcia

Pomona Faculty Publications and Research

No abstract provided.


Statistical Topology Via Morse Theory, Persistence And Nonparametric Estimation, Peter Bubenik, Gunnar Carlsson, Peter T. Kim, Zhiming Luo 2010 Cleveland State University

Statistical Topology Via Morse Theory, Persistence And Nonparametric Estimation, Peter Bubenik, Gunnar Carlsson, Peter T. Kim, Zhiming Luo

Mathematics and Statistics Faculty Publications

In this paper we examine the use of topological methods for multivariate statistics. Using persistent homology from computational algebraic topology, a random sample is used to construct estimators of persistent homology. This estimation procedure can then be evaluated using the bottleneck distance between the estimated persistent homology and the true persistent homology. The connection to statistics comes from the fact that when viewed as a nonparametric regression problem, the bottleneck distance is bounded by the sup-norm loss. Consequently, a sharp asymptotic minimax bound is determined under the sup–norm risk over H¨older classes of functions for the nonparametric regression problem on …


Bringing Toric Codes To The Next Dimension, Ivan Soprunov, Jenya Soprunova 2010 Cleveland State University

Bringing Toric Codes To The Next Dimension, Ivan Soprunov, Jenya Soprunova

Mathematics and Statistics Faculty Publications

This paper is concerned with the minimum distance computation for higher dimensional toric codes defined by lattice polytopes in $\mathbb{R}^n$. We show that the minimum distance is multiplicative with respect to taking the product of polytopes, and behaves in a simple way when one builds a k-dilate of a pyramid over a polytope. This allows us to construct a large class of examples of higher dimensional toric codes where we can compute the minimum distance explicitly.


Whitehead Products In Function Spaces: Quillen Model Formulae, Gregory Lupton, Samuel Bruce Smith 2010 Cleveland State University

Whitehead Products In Function Spaces: Quillen Model Formulae, Gregory Lupton, Samuel Bruce Smith

Mathematics and Statistics Faculty Publications

We study Whitehead products in the rational homotopy groups of a general component of a function space. For the component of any based map f : X→Y, in either the based or free function space, our main results express the Whitehead product directly in terms of the Quillen minimal model of f. These results follow from a purely algebraic development in the setting of chain complexes of derivations of differential graded Lie algebras, which is of interest in its own right. We apply the results to study the Whitehead length of function space components.


The Influences Of Microbial Diversity On Carbonate Geochemistry Across A Transition From Fresh To Saline Water In The Edwards Aquifer, Texas, Cassie Jo Gray 2010 Louisiana State University and Agricultural and Mechanical College

The Influences Of Microbial Diversity On Carbonate Geochemistry Across A Transition From Fresh To Saline Water In The Edwards Aquifer, Texas, Cassie Jo Gray

LSU Master's Theses

Microbially-mediated karstification through the production of metabolic byproducts has been well-documented in cave environments, but less is known about deep karstic settings. This research aimed to distinguish between microbial and geochemical influences on carbonate dissolution in the Edwards Aquifer, a prolific karst aquifer in central Texas, specifically from a transect of six wells across a transition from fresh to saline water in New Braunfels. For the first time, a portion of the aquifer’s bacterial diversity was examined from molecular 16S rRNA gene sequence analyses, which revealed that Alphaproteobacteria, Gammaproteobacteria, and Betaproteobacteria dominated the aquifer, with rare Bacteroidetes, Nitrospirae, and Firmicutes …


Getting Off The Ground With Ap Calculus, David Frank Woods 2010 Louisiana State University and Agricultural and Mechanical College

Getting Off The Ground With Ap Calculus, David Frank Woods

LSU Master's Theses

“The study of mathematics, like the Nile, begins in minuteness but ends in magnificence.” – Charles Caleb Colton Caught in a downward spiral, American mathematical students continue to be outperformed by their international peers as reported by the TIMSS. This has left educators scrambling to find an instructional strategy that will slow this decline in mathematical literacy. This thesis reports on the framework that a new teacher could use to develop and establish a successful AP Calculus program, while increasing mathematical literacy, equity in the classroom, and student achievement through the integration of educational technology into current instructional trends. This …


Likely Values Of The Higgs Vacuum Expectation Value, JF Donoghue, K Dutta, A Ross, M Tegmark 2010 University of Massachusetts Amherst

Likely Values Of The Higgs Vacuum Expectation Value, Jf Donoghue, K Dutta, A Ross, M Tegmark

Physics Department Faculty Publication Series

We make an estimate of the likelihood function for the Higgs vacuum expectation value (vev) by imposing anthropic constraints on the existence of atoms while allowing the other parameters of the standard model to also be variable. We argue that the most important extra ingredients are the Yukawa couplings, and for the intrinsic distribution of Yukawa couplings we use the scale-invariant distribution which is favored phenomenologically. The result is successful phenomenologically, favoring values close to the observed vev. We also discuss modifications that can change these conclusions. Our work supports the hypothesis that the anthropic constraints could be the origin …


Breaking Diffeomorphism Invariance And Tests For The Emergence Of Gravity, MM Anber, U Aydemir, JF Donoghue 2010 University of Massachusetts Amherst

Breaking Diffeomorphism Invariance And Tests For The Emergence Of Gravity, Mm Anber, U Aydemir, Jf Donoghue

Physics Department Faculty Publication Series

If general relativity is an emergent phenomenon, there may be small violations of diffeomorphism invariance. We propose a phenomenology of perturbatively small violations of general relativity by the inclusion of terms which break general covariance. These can be tested by matching to the Parameterized Post Newtonian (PPN) formalism. The most sensitive tests involve pulsar timing and provide an extremely strong bound, with a dimensionless constraint of order 10−20 relative to gravitational strength.


Search For Gravitational-Wave Inspiral Signals Associated With Short Gamma-Ray Bursts During Ligo's Fifth And Virgo's First Science Run, J. Abadie, B. P. Abbott, R. Abbott, T. Accadia, F. Acernese, R. Adhikari, P. Ajith, B. Allen, G. Allen, E. Amador Ceron, R. S. Amin, S. B. Anderson, W. G. Anderson, F. Antonucci, S. Aoudia, M. A. Arain, M. Araya, K. G. Arun, Y. Aso, S. Aston, P. Astone, P. Aufmuth, C. Aulbert, S. Babak, P. Baker, G. Ballardin, S. Ballmer, D. Barker, F. Barone, B. Barr 2010 University of Texas Rio Grande Valley

Search For Gravitational-Wave Inspiral Signals Associated With Short Gamma-Ray Bursts During Ligo's Fifth And Virgo's First Science Run, J. Abadie, B. P. Abbott, R. Abbott, T. Accadia, F. Acernese, R. Adhikari, P. Ajith, B. Allen, G. Allen, E. Amador Ceron, R. S. Amin, S. B. Anderson, W. G. Anderson, F. Antonucci, S. Aoudia, M. A. Arain, M. Araya, K. G. Arun, Y. Aso, S. Aston, P. Astone, P. Aufmuth, C. Aulbert, S. Babak, P. Baker, G. Ballardin, S. Ballmer, D. Barker, F. Barone, B. Barr

Physics and Astronomy Faculty Publications and Presentations

Progenitor scenarios for short gamma-ray bursts (short GRBs) include coalescenses of two neutron stars or a neutron star and black hole, which would necessarily be accompanied by the emission of strong gravitational waves. We present a search for these known gravitational-wave signatures in temporal and directional coincidence with 22 GRBs that had sufficient gravitational-wave data available in multiple instruments during LIGO's fifth science run, S5, and Virgo's first science run, VSR1. We find no statistically significant gravitational-wave candidates within a [ - 5, + 1)s window around the trigger time of any GRB. Using the Wilcoxon-Mann-Whitney U-test, we find no …


Searches For Gravitational Waves From Known Pulsars With Science Run 5 Ligo Data, B. P. Abbott, R. Abbott, F. Acernese, R. Adhikari, P. Ajith, B. Allen, G. Allen, M. Alshourbagy, R. S. Amin, S. B. Anderson, W. G. Anderson, F. Antonucci, S. Aoudia, M. A. Arain, M. Araya, H. Armandula, P. Armor, K. G. Arun, Y. Aso, S. Aston, P. Astone, P. Aufmuth, C. Aulbert, S. Babak, P. Baker, G. Ballardin, S. Ballmer, C. Barker, D. Barker, F. Barone 2010 University of Texas Rio Grande Valley

Searches For Gravitational Waves From Known Pulsars With Science Run 5 Ligo Data, B. P. Abbott, R. Abbott, F. Acernese, R. Adhikari, P. Ajith, B. Allen, G. Allen, M. Alshourbagy, R. S. Amin, S. B. Anderson, W. G. Anderson, F. Antonucci, S. Aoudia, M. A. Arain, M. Araya, H. Armandula, P. Armor, K. G. Arun, Y. Aso, S. Aston, P. Astone, P. Aufmuth, C. Aulbert, S. Babak, P. Baker, G. Ballardin, S. Ballmer, C. Barker, D. Barker, F. Barone

Physics and Astronomy Faculty Publications and Presentations

We present a search for gravitational waves from 116 known millisecond and young pulsars using data from the fifth science run of the LIGO detectors. For this search, ephemerides overlapping the run period were obtained for all pulsars using radio and X-ray observations. We demonstrate an updated search method that allows for small uncertainties in the pulsar phase parameters to be included in the search. We report no signal detection from any of the targets and therefore interpret our results as upper limits on the gravitational wave signal strength. The most interesting limits are those for young pulsars. We present …


Digital Commons powered by bepress