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Full-Text Articles in Physics

New Tests Of General Relativity, Quentin Bailey Jun 2019

New Tests Of General Relativity, Quentin Bailey

Quentin Bailey

The last decade has seen a rapid increase in the number of precision tests of relativity. This research has been motivated by the intriguing possibility that tiny deviations from relativity might arise in the underlying theory that is widely believed to successfully mesh General Relativity (GR) with quantum physics. Many of these tests have been analyzed within an effective field theory framework which generically describes possible deviations from exact relativity and contains some traditional test frameworks as limiting cases. One part of the activity has been a resurgence of interest in tests of relativity in the Minkowski-spacetime context, where Lorentz …


Tests Of Lorentz Symmetry In The Gravitational Sector, Aurélien Hees, Quentin G. Bailey, Adrien Bourgoin, Hélène Pihan-Le Bars, Christine Guerlin, Christophe Le Poncin-Lafitte Jun 2019

Tests Of Lorentz Symmetry In The Gravitational Sector, Aurélien Hees, Quentin G. Bailey, Adrien Bourgoin, Hélène Pihan-Le Bars, Christine Guerlin, Christophe Le Poncin-Lafitte

Quentin Bailey

Lorentz symmetry is one of the pillars of both General Relativity and the Standard Model of particle physics. Motivated by ideas about quantum gravity, unification theories and violations of CPT symmetry, a significant effort has been put the last decades into testing Lorentz symmetry. This review focuses on Lorentz symmetry tests performed in the gravitational sector. We briefly review the basics of the pure gravitational sector of the Standard-Model Extension (SME) framework, a formalism developed in order to systematically parametrize hypothetical violations of the Lorentz invariance. Furthermore, we discuss the latest constraints obtained within this formalism including analyses of the …


Prospects For Sme Tests With Experiments At Syrte And Lkb, C. Guerlin, H. Pihan-Le Bars, Q. G. Bailey, P. Wolf Jun 2019

Prospects For Sme Tests With Experiments At Syrte And Lkb, C. Guerlin, H. Pihan-Le Bars, Q. G. Bailey, P. Wolf

Quentin Bailey

Preliminary work has been done in order to assess the perspectives of metrology and fundamental physics atomic experiments at SYRTE and LKB in the search for physics beyond the Standard Model and General Relativity. The first studies we identified are currently ongoing with the Microscope mission and with a Cs fountain clock. The latter brings significant improvement on the proton-sector coefficient cTT down to the 10−17 GeV level.


Improved Tests Of Lorentz Invariance In The Matter Sector Using Atomic Clocks, H. Pihan-Le Bars, C. Guerlin, Q. G. Bailey, S. Bize, P. Wolf Jun 2019

Improved Tests Of Lorentz Invariance In The Matter Sector Using Atomic Clocks, H. Pihan-Le Bars, C. Guerlin, Q. G. Bailey, S. Bize, P. Wolf

Quentin Bailey

For the purpose of searching for Lorentz-invariance violation in the minimal Standard-Model Extension, we perfom a reanalysis of data obtained from the 133Cs fountain clock operating at SYRTE. The previous study led to new limits on eight components of the ˜cµν tensor, which quantifies the anisotropy of the proton’s kinetic energy. We recently derived an advanced model for the frequency shift of hyperfine Zeeman transition due to Lorentz violation and became able to constrain the ninth component, the isotropic coefficient c˜TT, which is the least well-constrained coefficient of ˜cµν. This model is based on a second-order boost Lorentz transformation from …


Lorentz-Violating Electromagnetostatics, Quentin G. Bailey Jun 2019

Lorentz-Violating Electromagnetostatics, Quentin G. Bailey

Quentin Bailey

In this talk, the stationary limit of Lorentz-violating electrodynamics is discussed. As illustrated by some simple examples, the general solution includes unconventional mixing of electrostatic and magnetostatic effects. I discuss a high-sensitivity null-type measurement, exploiting Lorentz-violating electromagnetostatic effects, that could improve existing limits on parity-odd coefficients for Lorentz violation in the photon sector.


Gravity Sector Of The Sme, Q. G. Bailey Jun 2019

Gravity Sector Of The Sme, Q. G. Bailey

Quentin Bailey

In this talk, the gravity sector of the effective field theory description of local Lorentz violation is discussed, including minimal and nonminimal curvature couplings. Also, recent experimental and observational analyses including solar-system ephemeris and short-range gravity tests are reviewed.


Interpreting Particle Motion In Low-Gravity, Asteroidal Conditions With Image Processing And Analysis, Gillian Gomer, Adrienne Dove, Michael Fraser, Seamus Anderson, Kristen John, Marc Fries Mar 2019

Interpreting Particle Motion In Low-Gravity, Asteroidal Conditions With Image Processing And Analysis, Gillian Gomer, Adrienne Dove, Michael Fraser, Seamus Anderson, Kristen John, Marc Fries

Gillian Gomer

Asteroids and moons are small, atmosphereless bodies with dynamic surface activity that complicates image analysis and selection of future exploration sites. To better understand the distributions of surface material (regolith), the Strata-1 experiment utilized the microgravity, vibrational environment of the International Space Station (ISS) to replicate asteroidal conditions. Image data was collected, in which we observe both times of disruptive “events” and more passive “non-events” that cause small changes. The experiment contained several types of material to simulate asteroid surfaces. Here we analyze a single tube that contained aspherical glass shards. We have written a Python routine to split the …


Analysis Of Regolith Simulant Stratification And Migration In An Asteroid-Like Environment, Gillian Gomer, Michael Fraser, Adrienne Dove, Seamus Anderson, Akbar Whizin, Kristen John, Marc Fries Mar 2018

Analysis Of Regolith Simulant Stratification And Migration In An Asteroid-Like Environment, Gillian Gomer, Michael Fraser, Adrienne Dove, Seamus Anderson, Akbar Whizin, Kristen John, Marc Fries

Gillian Gomer

No abstract provided.


Hypervolatiles In A Jupiter-Family Comet: Observations Of 45p/Honda–Mrkos–Pajdušáková Using Ishell At The Nasa-Irtf, Michael A. Disanti, Boncho P. Bonev, Neil Dello Russo, Ronald J. Vervack, Erika L. Gibb, Nathan X. Roth, Adam J. Mckay, Hideyo Kawakita, Lori M. Feaga, Harold A. Weaver Nov 2017

Hypervolatiles In A Jupiter-Family Comet: Observations Of 45p/Honda–Mrkos–Pajdušáková Using Ishell At The Nasa-Irtf, Michael A. Disanti, Boncho P. Bonev, Neil Dello Russo, Ronald J. Vervack, Erika L. Gibb, Nathan X. Roth, Adam J. Mckay, Hideyo Kawakita, Lori M. Feaga, Harold A. Weaver

Erika Gibb

We used the new high spectral resolution cross-dispersed facility spectrograph, iSHELL, at the NASA Infrared Telescope Facility on Maunakea, HI, to observe Jupiter-family comet (JFC) 45P/Honda–Mrkos–Pajdušáková. We report water production rates, as well as production rates and abundance ratios relative to H2O, for eight trace parent molecules (native ices), CO, CH4, H2CO, CH3OH, HCN, NH3, C2H2, and C2H6, on 2 days spanning UT 2017 January 6/7 and 7/8, shortly following perihelion. Trace species were measured simultaneously with H2O and/or OH prompt emission, a proxy for H2O production, thereby providing a robust and consistent means of establishing the native ice composition …


"Blinded By The Lines: Mid-Ir Spectra Of Mira Variables Taken With Spitzer", Dana Baylis-Aguirre, Michelle J. Creech-Eakman, Donald G. Luttermoser, Tina Gueth Aug 2017

"Blinded By The Lines: Mid-Ir Spectra Of Mira Variables Taken With Spitzer", Dana Baylis-Aguirre, Michelle J. Creech-Eakman, Donald G. Luttermoser, Tina Gueth

Donald G. Luttermoser

We present preliminary analysis of mid-infrared spectra of M-type and C-type Mira variables. Due to the brightness of this sample, it is straightforward to monitor changes with phase in the infrared spectral features of these regular pulsators. We have spectra of 25 Mira variables, taken with phase, using the Spitzer Infrared Spectrograph (IRS) high-resolution module. Each star has multiple spectra obtained over a one-year period from 2008-09. This is a rich, unique data set due to multiple observations of each star and the high signal-to-noise ratio from quick exposure times to prevent saturation of the IRS instrument. This paper focuses …


Gravitational-Wave Science With The Laser Interferometer Gravitational-Wave Observatory, Madeline Wade May 2017

Gravitational-Wave Science With The Laser Interferometer Gravitational-Wave Observatory, Madeline Wade

Madeline Wade

Gravitational-waves, as predicted by Einstein’s theory of general relativity, are oscillations of spacetime caused by the motion of masses. Although not yet directly detected, there is strong evidence for the existence of gravitational-waves. Detectable gravitational waves will come from dramatic astrophysical events, such as supernova explosions and collisions of black holes. The Laser Interferometer Gravitational-wave Observatory (LIGO) is a network of detectors designed to make the first direct detection of gravitational waves. The upgraded version of LIGO, Advanced LIGO (aLIGO), will offer a dramatic improvement in sensitivity that will virtually guarantee detections. Gravitational-wave detections will not only illuminate mysterious astrophysical …


Gravitational Waves From Rotating Neutron Stars And Compact Binary Systems, Leslie Wade May 2017

Gravitational Waves From Rotating Neutron Stars And Compact Binary Systems, Leslie Wade

Leslie Wade

It is widely anticipated that the first direct detections of gravitational waves will be made by advanced gravitational-wave detectors, such as the two Laser Interferometer Gravitational-wave Observatories (LIGO) and the Virgo interferometer. In preparation for the advanced detector era, I have worked on both detection and post-detection efforts involving two gravitational wave sources: isolated rotating neutron stars (NSs) and compact binary coalescences (CBCs). My dissertation includes three main research projects: 1) a population synthesis study assessing the detectability of isolated NSs, 2) a CBC search for intermediate-mass black-hole binaries (IMBHBs), and 3) new methods for directly measuring the neutron-star (NS) …


Beyond 3 Au From The Sun: The Hypervolatiles Ch4, C2h6, And Co In The Distant Comet C/2006 W3 (Christensen), Boncho P. Bonev, Geronimo L. Villanueva, Michael A. Disanti, Hermann Boehnhardt, Manuela Lippi, Erika L. Gibb, Lucas Paganini, Michael J. Mumma May 2017

Beyond 3 Au From The Sun: The Hypervolatiles Ch4, C2h6, And Co In The Distant Comet C/2006 W3 (Christensen), Boncho P. Bonev, Geronimo L. Villanueva, Michael A. Disanti, Hermann Boehnhardt, Manuela Lippi, Erika L. Gibb, Lucas Paganini, Michael J. Mumma

Erika Gibb

Comet C/2006 W3 (Christensen) remained outside a heliocentric distance (R h) of 3.1 au throughout its apparition, but it presented an exceptional opportunity to directly sense a suite of molecules released from its nucleus. The Cryogenic Infrared Echelle Spectrograph at ESO-VLT detected infrared emissions from the three "hypervolatiles" (CO, CH4, and C2H6) that have the lowest sublimation temperatures among species that are commonly studied in comets by remote sensing. Even at R h = 3.25 au, the production rate of each molecule exceeded those measured for the same species in a number of other comets, although these comets were observed …


The Composition Of Comet C/2012 K1 (Panstarrs) And The Distribution Of Primary Volatile Abundances Among Comets, Nathan X. Roth, Erika L. Gibb, Boncho P. Bonev, Michael A. Disanti, Michael J. Mumma, Geronimo L. Villanueva, Lucas Paganini Mar 2017

The Composition Of Comet C/2012 K1 (Panstarrs) And The Distribution Of Primary Volatile Abundances Among Comets, Nathan X. Roth, Erika L. Gibb, Boncho P. Bonev, Michael A. Disanti, Michael J. Mumma, Geronimo L. Villanueva, Lucas Paganini

Erika Gibb

On 2014 May 22 and 24 we characterized the volatile composition of the dynamically new Oort cloud comet C/2012 K1 (PanSTARRS) using the long-slit, high resolution (λ/Δλ ≈ 25,000) near-infrared echelle spectrograph (NIRSPEC) at the 10 m Keck II telescope on Maunakea, Hawaii. We detected fluorescent emission from six primary volatiles (H2O, HCN, CH4, C2H6, CH3OH, and CO). Upper limits were derived for C2H2, NH3, and H2CO. We report rotational temperatures, production rates, and mixing ratios (relative to water). Compared with median abundance ratios for primary volatiles in other sampled Oort cloud comets, trace gas abundance ratios in C/2012 K1 …


Thermal Plasmaspheric Morphology: Effect Of Geomagnetic And Solar Activity, Mark Anthony Reynolds, G. Ganguli, J.A. Fedder, J. Lemaire, R.R. Meier, D.J. Melendez-Alvira Mar 2017

Thermal Plasmaspheric Morphology: Effect Of Geomagnetic And Solar Activity, Mark Anthony Reynolds, G. Ganguli, J.A. Fedder, J. Lemaire, R.R. Meier, D.J. Melendez-Alvira

M. Anthony Reynolds

A multispecies kinetic model of the thermal plasma in the plasmasphere is used to predict the spatial dependence of the hydrogen ion and helium ion density and temperature for different levels of geomagnetic and solar activity. The particular convection electric field model chosen is intended for the time intervals between substorms. The plasma density and temperature in the equatorial plane are found to exhibit a local-time variation that is sensitive to the details of the convection electric field. In particular, the parallel temperature increases with altitude and the perpendicular temperature decreases with altitude, except in the postmidnight sector, features that …


Measurement Of The Stochasticity Of Low-Latitude Geomagnetic Temporal Variations, Mark Anthony Reynolds, James A. Wanliss Mar 2017

Measurement Of The Stochasticity Of Low-Latitude Geomagnetic Temporal Variations, Mark Anthony Reynolds, James A. Wanliss

M. Anthony Reynolds

Ground magnetometer measurements of total magnetic field strength from 6 stations at low latitudes were analyzed using power spectrum and Hurst range scaling techniques. The Hurst exponents for most of these time-series were near 0.5, which indicates stochasticity, with the highest latitude stations exhibiting some persistence with Hurst exponents greater than 0.6. Although no definite correlations are evident, the relative increase of the Hurst exponent with latitude suggests the possibility that the underlying dynamics of the magnetosphere change with latitude. This result may help quantify the dynamics of the inner magnetosphere itself without the direct presence of the solar wind …


Inversion Of Plasmaspheric Euv Remote Sensing Data From The Stp 72-1 Satellite, R.R. Meier, A.C. Nicholas, J.M. Picone, D.J. Melendez-Alvira, G. Ganguli, Mark Anthony Reynolds, E.C. Roelof Mar 2017

Inversion Of Plasmaspheric Euv Remote Sensing Data From The Stp 72-1 Satellite, R.R. Meier, A.C. Nicholas, J.M. Picone, D.J. Melendez-Alvira, G. Ganguli, Mark Anthony Reynolds, E.C. Roelof

M. Anthony Reynolds

Observations of the extreme ultraviolet emission of helium ions at 30.4 nm can be used to study the global shape of the plasmasphere and its dynamical response to geomagnetic forcing. In order to retrieve number densities of plasmaspheric He+ from such observations, we have developed a new inversion technique based on discrete inverse theory, which uses the optical data to optimize a parameterized model of the He+ distribution. We apply this inversion technique to several orbits of data obtained from the Naval Research Laboratory extreme ultraviolet photometric experiment launched on the STP 72-1 satellite in October 1972. The inversion is …


Exotic Statistics For Strings In 4d Bf Theory, John C. Baez, Derek K. Wise, Alissa S. Crans Dec 2016

Exotic Statistics For Strings In 4d Bf Theory, John C. Baez, Derek K. Wise, Alissa S. Crans

Alissa Crans

After a review of exotic statistics for point particles in 3d BF theory, and especially 3d quantum gravity, we show that string-like defects in 4d BF theory obey exotic statistics governed by the 'loop braid group'. This group has a set of generators that switch two strings just as one would normally switch point particles, but also a set of generators that switch two strings by passing one through the other. The first set generates a copy of the symmetric group, while the second generates a copy of the braid group. Thanks to recent work of Xiao-Song Lin, we can …


En Route To Destruction: The Evolution In Composition Of Ices In Comet D/2012 S1 (Ison) Between 1.2 And 0.34 Au From The Sun As Revealed At Infrared Wavelengths, M. A. Disanti, B. P. Bonev, E. L. Gibb, L. Paganini, G. L. Villanueva, M. J. Mumma, J. V. Keane, G. A. Blake, N. Dello Russo, K. J. Meech, R. J. Vervack, A. J. Mckay Mar 2016

En Route To Destruction: The Evolution In Composition Of Ices In Comet D/2012 S1 (Ison) Between 1.2 And 0.34 Au From The Sun As Revealed At Infrared Wavelengths, M. A. Disanti, B. P. Bonev, E. L. Gibb, L. Paganini, G. L. Villanueva, M. J. Mumma, J. V. Keane, G. A. Blake, N. Dello Russo, K. J. Meech, R. J. Vervack, A. J. Mckay

Erika Gibb

We report production rates for H2O and eight trace molecules (CO, C2H6, CH4, CH3OH, NH3, H2CO, HCN, C2H2) in the dynamically new, Sun-grazing Comet C/2012 S1 (ISON), using high-resolution spectroscopy at Keck II and the NASA IRTF on 10 pre-perihelion dates encompassing heliocentric distances Rh = 1.21–0.34 AU. Measured water production rates spanned two orders of magnitude, consistent with a long-term heliocentric power law Q(H2O) ${\rm{\propto }}{R}_{{\rm{h}}}^{(-3.1\pm 0.1)}$. Abundance ratios for CO, C2H6, and CH4 with respect to H2O remained constant with Rh and below their corresponding mean values measured among a dominant sample of Oort Cloud comets. CH3OH was …


High Gravitational Waveform Accuracy At Null Infinity, Maria Babiuc-Hamilton Jul 2015

High Gravitational Waveform Accuracy At Null Infinity, Maria Babiuc-Hamilton

Maria C. Babiuc-Hamilton

The aim of Cauchy-characteristic extraction is to provide a standardized waveform extraction tool for the numerical relativity community. The new extraction tool contains major improvements and corrections to previous versions and displays convergence. The error introduced by CCE satisfies the time domain criteria required for advanced LIGO data analysis. The importance of accurate waveforms to the gravitational wave astronomy has created an urgency for tools like CCE. The source code has been released to the public and is available as part of the Einstein Toolkit. We welcome applications to a variety of generic Cauchy codes implementing Einstein Equations of General …


Aliasing Reduction In Staring Infrared Imagers Utilizing Subpixel Techniques, Joseph C. Gillette, Thomas M. Stadtmiller, Russell C. Hardie Mar 2015

Aliasing Reduction In Staring Infrared Imagers Utilizing Subpixel Techniques, Joseph C. Gillette, Thomas M. Stadtmiller, Russell C. Hardie

Russell C. Hardie

We introduce and analyze techniques for the reduction of aliased signal energy in a staring infrared imaging system. A standard staring system uses a fixed two-dimensional detector array that corresponds to a fixed spatial sampling frequency determined by the detector pitch or spacing. Aliasing will occur when sampling a scene containing spatial frequencies exceeding half the sampling frequency. This aliasing can significantly degrade the image quality. The aliasing reduction schemes presented here, referred to as microscanning, exploit subpixel shifts between time frames of an image sequence. These multiple images are used to reconstruct a single frame with reduced aliasing. If …


Intensities, Broadening And Narrowing Parameters In The Ν3 Band Of Methane, Et-Touhami Es-Sebbar, Aamir Farooq Aug 2014

Intensities, Broadening And Narrowing Parameters In The Ν3 Band Of Methane, Et-Touhami Es-Sebbar, Aamir Farooq

Dr. Et-touhami Es-sebbar

The P-branch of methane׳s ν3 band is probed to carry out an extensive study of the 2905–2908 cm−1 infrared spectral region. Absolute line intensities as well as N2-, O2-, H2-, He-, Ar- and CO2-broadening coefficients are determined for nine transitions at room temperature. Narrowing parameters due to the Dicke effect have also been investigated. A narrow emission line-width (~0.0001 cm−1) difference-frequency-generation (DFG) laser system is used as the tunable light source. To retrieve the CH4 spectroscopic parameters, Voigt and Galatry profiles were used to simulate the measured line shape of the individual transitions.


C/2013 R1 (Lovejoy) At Ir Wavelengths And The Variability Of Co Abundances Among Oort Cloud Comets, L. Paganini, M. J. Mumma, G. L. Villanueva, J. V. Keane, G. A. Blake, B. P. Bonev, M. A. Disanti, E. L. Gibb, K. J. Meech Aug 2014

C/2013 R1 (Lovejoy) At Ir Wavelengths And The Variability Of Co Abundances Among Oort Cloud Comets, L. Paganini, M. J. Mumma, G. L. Villanueva, J. V. Keane, G. A. Blake, B. P. Bonev, M. A. Disanti, E. L. Gibb, K. J. Meech

Erika Gibb

We report production rates, rotational temperatures, and related parameters for gases in C/2013 R1 (Lovejoy) using the Near InfraRed SPECtrometer at the Keck Observatory, on six UT dates spanning heliocentric distances (Rh ) that decreased from 1.35 AU to 1.16 AU (pre-perihelion). We quantified nine gaseous species (H2O, OH*, CO, CH4, HCN, C2H6, CH3OH, NH3, and NH2) and obtained upper limits for two others (C2H2 and H2CO). Compared with organics-normal comets, our results reveal highly enriched CO, (at most) slightly enriched CH3OH, C2H6, and HCN, and CH4 consistent with "normal", yet depleted, NH3, C2H2, and H2CO. Rotational temperatures increased from …


Basic Astronomy Labs, Terry L. Smith, Michael D. Reynolds, Jay S. Huebner Jul 2014

Basic Astronomy Labs, Terry L. Smith, Michael D. Reynolds, Jay S. Huebner

Jay S Huebner

Providing the tools and know-how to apply the principles of astronomy first-hand, these 43 laboratory exercises each contain an introduction that clearly shows budding astronomers why the particular topic of that lab is of interest and relevant to astronomy. About one-third of the exercises are devoted solely to observation, and no mathematics is required beyond simple high school algebra and trigonometry.Organizes exercises into six major topics—sky, optics and spectroscopy, celestial mechanics, solar system, stellar properties, and exploration and other topics—providing clear outlines of what is involved in the exercise, its purpose, and what procedures and apparatus are to be used. …


The Unexpectedly Bright Comet C/2012 F6 (Lemmon) Unveiled At Near-Infrared Wavelengths, Lucas Paganini, Michael A. Disanti, Michael J. Mumma, Geronimo L. Villanueva, Boncho P. Bonev, Jacqueline V. Keane, Erika L. Gibb, Hermann Boehnhardt, Karen J. Meech Dec 2013

The Unexpectedly Bright Comet C/2012 F6 (Lemmon) Unveiled At Near-Infrared Wavelengths, Lucas Paganini, Michael A. Disanti, Michael J. Mumma, Geronimo L. Villanueva, Boncho P. Bonev, Jacqueline V. Keane, Erika L. Gibb, Hermann Boehnhardt, Karen J. Meech

Erika Gibb

We acquired near-infrared spectra of the Oort cloud comet C/2012 F6 (Lemmon) at three different heliocentric distances (R h) during the comet's 2013 perihelion passage, providing a comprehensive measure of the outgassing behavior of parent volatiles and cosmogonic indicators. Our observations were performed pre-perihelion at R h = 1.2 AU with CRIRES (on 2013 February 2 and 4), and post-perihelion at R h = 0.75 AU with CSHELL (on March 31 and April 1) and R h = 1.74 AU with NIRSPEC (on June 20). We detected 10 volatile species (H2O, OH* prompt emission, C2H6, CH3OH, H2CO, HCN, CO, CH4, …


Detection Of Ch4 In The Gv Tau N Protoplanetary Disk, Erika L. Gibb, David Horne Oct 2013

Detection Of Ch4 In The Gv Tau N Protoplanetary Disk, Erika L. Gibb, David Horne

Erika Gibb

T Tauri stars are low mass young stars that may serve as analogs to the early solar system. Observations of organic molecules in the protoplanetary disks surrounding T Tauri stars are important for characterizing the chemical and physical processes that lead to planet formation. Searches for undetected molecules, particularly in the inner, planet forming regions of these disks are important for testing protoplanetary disk chemical models and for understanding the evolution of volatiles through the star and planet formation process. We used NIRSPEC on Keck 2 to perform a high resolution (λ/Δλ ~ 25,000) L-band survey of T Tauri star …


High Precision K-Shell Photoabsorption Cross Sections For Atomic Oxygen: Experiment And Theory, Brendan M. Mclaughlin, C P. Ballance, K P. Bowen, D J. Gardenghi, Wayne C. Stolte Jun 2013

High Precision K-Shell Photoabsorption Cross Sections For Atomic Oxygen: Experiment And Theory, Brendan M. Mclaughlin, C P. Ballance, K P. Bowen, D J. Gardenghi, Wayne C. Stolte

Wayne C. Stolte

Photoabsorption of atomic oxygen in the energy region below the 1s −1 threshold in X-ray spectroscopy from Chandra and XMM-Newton is observed in a variety of X-ray binary spectra. Photoabsorption cross sections determined from an R-matrix method with pseudo-states and new, high precision measurements from the Advanced Light Source (ALS) are presented. High-resolution spectroscopy with E/ΔE ≈ 4250 ± 400 was obtained for photon energies from 520 eV to 555 eV at an energy resolution of 124 ± 12 meV FWHM. K-shell photoabsorption cross section measurements were made with a re-analysis of previous experimental data on atomic oxygen at the …


Spectro-Astrometry Of Water In Dr Tauri, Logan R. Brown, Matthew R. Troutman, Erika L. Gibb May 2013

Spectro-Astrometry Of Water In Dr Tauri, Logan R. Brown, Matthew R. Troutman, Erika L. Gibb

Erika Gibb

We present high-resolution, near-infrared spectro-astrometric (SA) data for the T Tauri star DR Tau using NIRSPEC at the Keck II telescope. Spectro-astrometry obtains sub-seeing spatial information from emission lines originating in a non-point source object, such as a circumstellar disk. We report the first detection of water SA signatures in a protoplanetary disk. Three water features near 3 μm were averaged together to produce the total signal analyzed. Using a disk model, we constrained the position angle of the disk (~140°), the inclination of the disk (~13°), and the emitting region of the emission lines (~0.056-0.38 AU).


Wireless Transmission Network : A Imagine, Radhey Shyam Meena Engineer, Neeraj Kumar Garg Asst.Prof Apr 2013

Wireless Transmission Network : A Imagine, Radhey Shyam Meena Engineer, Neeraj Kumar Garg Asst.Prof

Radhey Shyam Meena

World cannot be imagined without electrical power. Generally the power is transmitted through transmission networks. This paper describes an original idea to eradicate the hazardous usage of electrical wires which involve lot of confusion in particularly organizing them. Imagine a future in which wireless power transfer is feasible: cell phones, household robots, mp3 players, laptop computers and other portable electronic devices capable of charging themselves without ever being plugged in freeing us from that final ubiquitous power wire. This paper includes the techniques of transmitting power without using wires with an efficiency of about 95% with non-radioactivemethods. In this paper …


Battery Energy Storage System In Solar Power Generation, Radhey Shyam Meena Er., Deepa Sharma Mar 2013

Battery Energy Storage System In Solar Power Generation, Radhey Shyam Meena Er., Deepa Sharma

Radhey Shyam Meena

Grid-connected solar PV dramatically changes the load profile of an electric utility customer. The expected widespread adoption of solar generation by customers on the distribution system poses significant challenges to system operators both in transient and steady state operation, from issues including voltage swings, sudden weather-induced changes in generation, and legacy protective devices designed with one-way power flow in mind