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1

Measurement of the x-ray mass attenuation coefficients of gold in the 38?50-keV energy range  

SciTech Connect

We used synchrotron x rays to measure the x-ray mass attenuation coefficients of gold at nine energies from 38 to 50 keV with accuracies of 0.1%. Our results are much more accurate than previous measurements in this energy range. A comparison of our measurements with calculated mass attenuation coefficients shows that our measurements fall almost exactly midway between the XCOM and FFAST calculated theoretical values, which differ from one another in this energy region by about 4%, even though the range includes no absorption edge. The consistency and accuracy of these measurements open the way to investigations of the x-ray attenuation in the region of the L absorption edge of gold.

Islam, M.T.; Rae, N.A.; Glover, J.L.; Barnea, Z.; de Jonge, M.D.; Tran, C.Q.; Wang, J.; Chantler, C.T. (Melbourne)

2010-11-12T23:59:59.000Z

2

X-ray attenuation properties of stainless steel (u)  

SciTech Connect

Stainless steel vessels are used to enclose solid materials for studying x-ray radiolysis that involves gas release from the materials. Commercially available stainless steel components are easily adapted to form a static or a dynamic condition to monitor the gas evolved from the solid materials during and after the x-ray irradiation. Experimental data published on the x-ray attenuation properties of stainless steel, however, are very scarce, especially over a wide range of x-ray energies. The objective of this work was to obtain experimental data that will be used to determine how a poly-energetic x-ray beam is attenuated by the stainless steel container wall. The data will also be used in conjunction with MCNP (Monte Carlos Nuclear Particle) modeling to develop an accurate method for determining energy absorbed in known solid samples contained in stainless steel vessels. In this study, experiments to measure the attenuation properties of stainless steel were performed for a range of bremsstrahlung x-ray beams with a maximum energy ranging from 150 keV to 10 MeV. Bremsstrahlung x-ray beams of these energies are commonly used in radiography of engineering and weapon components. The weapon surveillance community has a great interest in understanding how the x-rays in radiography affect short-term and long-term properties of weapon materials.

Wang, Lily L [Los Alamos National Laboratory; Berry, Phillip C [Los Alamos National Laboratory

2009-01-01T23:59:59.000Z

3

Determination of Mass Attenuation Coefficients for CuInSe2 and CuGaSe2 Semiconductors  

SciTech Connect

This work presents mass attenuation coefficients values of CuInSe2 and CuGaSe2 semiconductor thin films commonly used in photovoltaic devices. The mass attenuation coefficients were measured at different energies from 11.9 to 37.3 keV by using the secondary excitation method. Monochromatic photons were obtained using the Br, Sr, Mo, Cd, Te, Ba and Nd secondary targets. 59.5 keV gamma rays emitted from an annular Am-241 radioactive source were used to excite secondary targets. Characteristic X-rays emitted from secondary target were counted by a Si(Li) detector with a resolution of 0.16 keV at 5.9 keV. The measured values were compared with theoretical values calculated using WinXCOM program.

Celik, Ahmet; Cevik, Ugur; Baltas, Hasan; Bacaksiz, Emin [Department of Physics, Faculty of Arts and Sciences, Karadeniz Technical University, 61080 Trabzon (Turkey)

2007-04-23T23:59:59.000Z

4

The X-ray attenuation characteristics and density of human calcaneal marrow do not change significantly during adulthood  

E-Print Network (OSTI)

The X-ray attenuation characteristics and density of human calcaneal marrow do not change be a significant source of error in measurements of bone density when using X-ray and ultrasound imaging modalities calcanei (28 males, 6 females, ages 17­65 years). The density and energy-dependent linear X-ray attenuation

Stanford University

5

Attenuation of VHE Gamma Rays by the Milky Way Interstellar Radiation Field  

SciTech Connect

The attenuation of very high energy gamma rays by pair production on the Galactic interstellar radiation field has long been thought of as negligible. However, a new calculation of the interstellar radiation field consistent with multi-wavelength observations by DIRBE and FIRAS indicates that the energy density of the Galactic interstellar radiation field is higher, particularly in the Galactic center, than previously thought. We have made a calculation of the attenuation of very high energy gamma rays in the Galaxy using this new interstellar radiation field which takes into account its nonuniform spatial and angular distributions. We find that the maximum attenuation occurs around 100 TeV at the level of about 25% for sources located at the Galactic center, and is important for both Galactic and extragalactic sources.

Moskalenko, Igor V.; /Stanford U., HEPL; Porter, Troy A.; /Louisiana State U.; Strong, Andrew W.; /Garching, Max Planck Inst., MPE

2006-04-19T23:59:59.000Z

6

Spatial Gradients in Particle Reinforced Polymers Characterized by X-Ray Attenuation and Laser Confocal Microscopy  

SciTech Connect

The goal of this work is to develop techniques for measuring gradients in particle concentration within filled polymers, such as encapsulant. A high concentration of filler particles is added to such materials to tailor physical properties such as thermal expansion coefficient. Sedimentation and flow-induced migration of particles can produce concentration gradients that are most severe near material boundaries. Therefore, techniques for measuring local particle concentration should be accurate near boundaries. Particle gradients in an alumina-filled epoxy resin are measured with a spatial resolution of 0.2 mm using an x-ray beam attenuation technique, but an artifact related to the finite diameter of the beam reduces accuracy near the specimen's edge. Local particle concentration near an edge can be measured more reliably using microscopy coupled with image analysis. This is illustrated by measuring concentration profiles of glass particles having 40 {micro}m median diameter using images acquired by a confocal laser fluorescence microscope. The mean of the measured profiles of volume fraction agrees to better than 3% with the expected value, and the shape of the profiles agrees qualitatively with simple theory for sedimentation of monodisperse particles. Extending this microscopy technique to smaller, micron-scale filler particles used in encapsulant for microelectronic devices is illustrated by measuring the local concentration of an epoxy resin containing 0.41 volume fraction of silica.

LAGASSE,ROBERT R.; THOMPSON,KYLE R.

2000-06-12T23:59:59.000Z

7

A COMPARISON OF MEASURED AND CALCULATED GAMMA RAY ATTENUATION FOR A COMMON COUNTING GEOMETRY  

SciTech Connect

In order to perform quantitative gamma spectroscopy, it is necessary to know the sample-specific detection efficiency for photons as a function of energy. The detection efficiency, along with the branching ratio for the isotope and gamma ray of interest, is used to convert observed counts/second to actual disintegrations/second, and, hence, has a large effect on the accuracy of the measurement. In cases where the geometry of the source is simple and reproducible, such as a point source, small vial of solid, or jar of liquid, geometry-specific standards may be counted to determine the detection efficiency. In cases where the samples are large, irregular, or unique, this method generally cannot be used. For example, it is impossible to obtain a NIST-traceable standard glovebox or 55-gallon drum. In these cases, a combination of measured absolute detector efficiency and calculated sample-specific correction factors is commonly used. The correction factors may be calculated via Monte Carlo simulation of the item (the method used by Canberra's ISOCS system), or via semi-empirical calculation of matrix and container attenuations based on the thickness and composition of the container and radioactive matrix (ISOTOPIC by EG&G Ortec uses this method). The accuracy of these correction factors for specific geometries is often of vital interest when assessing the quality of gamma spectroscopy data. During the Building 251 Risk-Reduction Project, over 100 samples of high activity actinides will be characterized via gamma spectroscopy, typically without removing the material from the current storage containers. Most of the radioactive materials in B-251 are stored in cylindrical stainless steel canisters (called USV containers, after the Underground Storage Vaults they are commonly stored in), 13 cm in diameter, by 28 cm high, with walls that are 1.8 mm thick. While the actual samples have a variety of configurations inside the USV container, a very common configuration is the material (usually as an oxide powder pellet of approximately 2 cm diameter by {approx}2 mm thick) in a squat glass jar, with the jar placed in a thin steel food-pack can, which is then placed in the bottom of the USV canister. During data acquisition, the USV containers are typically rotated at approximately 4 rpm on a turntable to eliminate errors due to the material not being centered in the can, or attenuation not being isotropic. An aluminum plate is placed over the container, secured by three vertical rods, to securely hold the container. Pictures of both the containers, and this typical counting configuration are shown below.

Gaylord, R F

2004-02-26T23:59:59.000Z

8

Flat panel X-ray detector with reduced internal scattering for improved attenuation accuracy and dynamic range  

DOE Patents (OSTI)

An x-ray detector is disclosed that has had all unnecessary material removed from the x-ray beam path, and all of the remaining material in the beam path made as light and as low in atomic number as possible. The resulting detector is essentially transparent to x-rays and, thus, has greatly reduced internal scatter. The result of this is that x-ray attenuation data measured for the object under examination are much more accurate and have an increased dynamic range. The benefits of this improvement are that beam hardening corrections can be made accurately, that computed tomography reconstructions can be used for quantitative determination of material properties including density and atomic number, and that lower exposures may be possible as a result of the increased dynamic range.

Smith, Peter D. (Santa Fe, NM); Claytor, Thomas N. (White Rock, NM); Berry, Phillip C. (Albuquerque, NM); Hills, Charles R. (Los Alamos, NM)

2010-10-12T23:59:59.000Z

9

X-ray views of neutron star low-mass X-ray binaries  

E-Print Network (OSTI)

A neutron star low-mass X-ray binary is a binary stellar system with a neutron star and a low-mass companion star rotating around each other. In this system the neutron star accretes mass from the companion, and as this matter falls into the deep potential well of the neutron star, the gravitational potential energy is released primarily in the X-ray wavelengths. Such a source was first discovered in X-rays in 1962, and this discovery formally gave birth to the "X-ray astronomy". In the subsequent decades, our knowledge of these sources has increased enormously by the observations with several X-ray space missions. Here we give a brief overview of our current understanding of the X-ray observational aspects of these systems.

Sudip Bhattacharyya

2010-02-24T23:59:59.000Z

10

Testing varying neutrino mass with short gamma ray bursts  

Science Journals Connector (OSTI)

In this paper we study the possibility of probing for the absolute neutrino mass and its variation with short gamma ray burst (GRB). We have calculated the flight time difference between a massive neutrino and a photon in two different approaches to the mass varying neutrinos. Firstly we parametrize the neutrino mass as a function of the redshift in a model independent way, then we consider two specific models where the neutrino mass varies during the evolution of the quintessence fields. Our calculations show in general the value of the time delay is changed substantially relative to a constant neutrino mass and is also expected to be larger than the duration time of the short GRB.

Hong Li; Zigao Dai; Xinmin Zhang

2005-06-07T23:59:59.000Z

11

THE EXTRAGALACTIC BACKGROUND LIGHT FROM THE MEASUREMENTS OF THE ATTENUATION OF HIGH-ENERGY GAMMA-RAY SPECTRUM  

SciTech Connect

The attenuation of high-energy gamma-ray spectrum due to the electron-positron pair production against the extragalactic background light (EBL) provides an indirect method to measure the EBL of the universe. We use the measurements of the absorption features of the gamma-rays from blazars as seen by the Fermi Gamma-ray Space Telescope to explore the EBL flux density and constrain the EBL spectrum, star formation rate density (SFRD), and photon escape fraction from galaxies out to z = 6. Our results are basically consistent with the existing determinations of the quantities. We find a larger photon escape fraction at high redshifts, especially at z = 3, compared to the result from recent Ly{alpha} measurements. Our SFRD result is consistent with the data from both gamma-ray burst and ultraviolet (UV) observations in the 1{sigma} level. However, the average SFRD we obtain at z {approx}> 3 matches the gamma-ray data better than the UV data. Thus our SFRD result at z {approx}> 6 favors the fact that star formation alone is sufficiently high enough to reionize the universe.

Gong Yan; Cooray, Asantha [Department of Physics and Astronomy, University of California, Irvine, CA 92697 (United States)

2013-07-20T23:59:59.000Z

12

Compact Stars in low-mass X-ray binaries  

E-Print Network (OSTI)

We propose a model for compact stars in low-mass X-ray binaries(LMXBs) namely KS 1731-260, EXO 1745-248 and 4U 1608-52. Here we investigate the physical phenomena of a compact star in the LMXBs. Using our model, we have calculated central density, surface density, mass(M) and red-shift for the above mentioned compact stars, which is very much consistent with the reported data. We also obtain the possible equation of state(EOS) of the stars which is physically acceptable.

Sk. Monowar Hossein; Sajahan Molla; Md. Abdul Kayum Jafry; Mehedi Kalam

2014-08-13T23:59:59.000Z

13

Attenuation corrections for X-ray and neutron fibre diffraction studies  

Science Journals Connector (OSTI)

The form of the transmission factor for sample geometries encountered in X-ray and neutron fibre diffraction studies is considered.

Langan, P.

1995-02-01T23:59:59.000Z

14

X-ray Spectroscopy of O Supergiant Winds: Shock Physics, Clumping, and Mass-Loss Rates  

E-Print Network (OSTI)

X-ray Spectroscopy of O Supergiant Winds: Shock Physics, Clumping, and Mass-Loss Rates David Cohen Li (Swarthmore '16), Kelley Langhans (Swarthmore '16) #12;Talk Outline Context of O star X-ray emission: wind shocks 1. X-ray constraints on the shocked wind plasma 2. X-ray absorption as a mass

Cohen, David

15

A mass of less than 15 solar masses for the black hole in an ultraluminous X-ray source  

E-Print Network (OSTI)

Most ultraluminous X-ray sources (ULXs) display a typical set of properties not seen in Galactic stellar-mass black holes (BHs): higher luminosity Lx > 3 10^39 erg/s, unusually soft X-ray components (kT solar masses. Our results demonstrate that in P13, soft thermal emission and spectral curvature are indeed signatures of supercritical accretion. ...

Motch, C; Soria, R; Grisé, F; Pietrzy?ski, G

2014-01-01T23:59:59.000Z

16

A detailed study of the optical attenuation of gamma-ray bursts in the Swift era  

E-Print Network (OSTI)

We present optical and near-infrared (NIR) photometry of 24 gamma-ray bursts (GRBs) detected by the Swift satellite and rapidly observed by the Reionization and Transients Infrared/Optical (RATIR) camera. We compare the optical flux at a fiducial time of 11 hours after the high-energy trigger to that in the X-ray regime to quantify optical darkness. 50 per cent (12/24) of all bursts in our sample and 55 per cent (12/22) of long GRBs are optically dark, which is statistically consistently with previous studies. Fitting RATIR optical and NIR spectral energy distributions (SEDs) of 16 GRBs, most (6/7) optically dark GRBs either occur at high-redshift ($z>4.5$) or have a high dust content in their host galaxies ($A_{\\rm V} > 0.3$). Performing K-S tests, we compare the RATIR sample to those previously presented in the literature, finding our distributions of redshift, optical darkness, host dust extinction and X-ray derived column density to be consistent. The one reported discrepancy is with host galaxy dust cont...

Littlejohns, O M; Cucchiara, A; Watson, A M; Fox, O D; Lee, W H; Kutyrev, A S; Richer, M G; Klein, C R; Prochaska, J X; Bloom, J S; Troja, E; Ramirez-Ruiz, E; de Diego, J A; Georgiev, L; González, J; Román-Zúñiga, C G; Gehrels, N; Moseley, H

2014-01-01T23:59:59.000Z

17

Did a gamma-ray burst initiate the late Ordovician mass extinction?  

E-Print Network (OSTI)

Did a gamma-ray burst initiate the late Ordovician mass extinction? A.L. Melott1 , B.S. Lieberman2 Abstract: Gamma-ray bursts (GRBs) produce a flux of radiation detectable across the observable Universe words: Population and evolution, mass extinction, gamma-ray burst, Ordovician, ultraviolet ozone

Jackman, Charles H.

18

Isotropic star in low-mass X-ray binaries and X-ray pulsars  

E-Print Network (OSTI)

We present a model for compact stars in the low mass X-ray binaries(LMXBs) and X-ray pulsars using a metric given by John J. Matese and Patrick G. Whitman \\citep{Matese and Whitman1980}. Here the field equations are reduced to a system of two algebraic equations considering the isotropic pressure. Compact star candidates 4U 1820-30(radius=10km) in LMXBs, and Her X-1(radius=7.7km), SAX J 1808.4-3658(SS1)(radius=7.07km) and SAX J 1808.4-3658(SS2)(radius=6.35km) in X-ray pulsars satisfy all the energy conditions, TOV-equation and stability condition. From our model, we have derived mass($M$), central density($\\rho_{0}$), suface density($\\rho_{b}$), central pressure($p_{0}$), surface pressure($p_{b}$) and surface red-shift($Z_{s}$) of the above mentioned stars, which are very much consistant with the observed/reported datas\\citep{N. K. Glendenning1997,Gondek2000}. We have also observe the adiabatic index($\\gamma$>4/3) of the above steller objects.

Mehedi Kalam; Sk. Monowar Hossein; Sajahan Molla

2014-10-01T23:59:59.000Z

19

Neutron Star Masses and Radii from Quiescent Low-Mass X-ray Binaries  

E-Print Network (OSTI)

We perform a systematic analysis of neutron star radius constraints from five quiescent low-mass X-ray binaries and examine how they depend on measurements of their distances and amounts of intervening absorbing material, as well as their assumed atmospheric compositions. We construct and calibrate to published results a semi-analytic model of the neutron star atmosphere which approximates these effects for the predicted masses and radii. Starting from mass and radius probability distributions established from hydrogen-atmosphere spectral fits of quiescent sources, we apply this model to compute alternate sets of probability distributions. We perform Bayesian analyses to estimate neutron star mass-radius curves and equation of state (EOS) parameters that best-fit each set of distributions, assuming the existence of a known low-density neutron star crustal EOS, a simple model for the high-density EOS, causality, and the observation that the neutron star maximum mass exceeds $2~M_\\odot$. We compute the posterior probabilities for each set of distance measurements and assumptions about absorption and composition. We find that, within the context of our assumptions and our parameterized EOS models, some absorption models are disfavored. We find that neutron stars composed of hadrons are favored relative to those with exotic matter with strong phase transitions. In addition, models in which all five stars have hydrogen atmospheres are found to be weakly disfavored. Our most likely models predict neutron star radii that are consistent with current experimental results concerning the nature of the nucleon-nucleon interaction near the nuclear saturation density.

James M. Lattimer; Andrew W. Steiner

2014-03-19T23:59:59.000Z

20

E-Print Network 3.0 - attenuate severe sepsis-associated Sample...  

NLE Websites -- All DOE Office Websites (Extended Search)

SPECT imaging. Summary: the attenuation correction in the case of 3D attenuated ray transform with a parallel geometry. We suppose... that the attenuation function is available...

Note: This page contains sample records for the topic "ray mass attenuation" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

(No) dimming of X-ray clusters beyond z~1 at fixed mass: crude redhshifts and masses from raw X-ray and SZ data  

E-Print Network (OSTI)

Scaling relations in the LCDM Cosmology predict that for a given mass the clusters formed at larger redshift are hotter, denser and therefore more luminous in X-rays than their local z~0 counterparts. This effect overturns the decrease in the observable X-ray flux so that it does not decrease at z > 1, but instead raises slowly, similar to the SZ signal. Provided that scaling relations remain valid at larger redshifts, X-ray surveys will not miss massive clusters at any redshift, no matter how far they are. At the same time, the difference in scaling with mass and distance of the observable SZ and X-ray signals from galaxy clusters at redshifts zX-ray (e.g., by SRG/eRosita) and SZ (e.g. Planck, SPT, ACT and CoRe+).

Churazov, E; Sunyaev, R

2015-01-01T23:59:59.000Z

22

X-ray spectroscopy of neutron star low-mass X-ray binaries  

E-Print Network (OSTI)

In this thesis, I present work spanning a variety of topics relating to neutron star lowmass X-ray binaries (LMXBs) and utilize spectral information from X-ray observations to further our understanding of these sources. ...

Krauss, Miriam Ilana

2007-01-01T23:59:59.000Z

23

Wormholes, Gamma Ray Bursts and the Amount of Negative Mass in the Universe  

E-Print Network (OSTI)

In this essay, we assume that negative mass objects can exist in the extragalactic space and analyze the consequences of their microlensing on light from distant Active Galactic Nuclei. We find that such events have very similar features to some observed Gamma Ray Bursts and use recent satellite data to set an upper bound to the amount of negative mass in the universe.

Diego F. Torres; Gustavo E. Romero; Luis A. Anchordoqui

1998-05-19T23:59:59.000Z

24

Control algorithms for dynamic attenuators  

SciTech Connect

Purpose: The authors describe algorithms to control dynamic attenuators in CT and compare their performance using simulated scans. Dynamic attenuators are prepatient beam shaping filters that modulate the distribution of x-ray fluence incident on the patient on a view-by-view basis. These attenuators can reduce dose while improving key image quality metrics such as peak or mean variance. In each view, the attenuator presents several degrees of freedom which may be individually adjusted. The total number of degrees of freedom across all views is very large, making many optimization techniques impractical. The authors develop a theory for optimally controlling these attenuators. Special attention is paid to a theoretically perfect attenuator which controls the fluence for each ray individually, but the authors also investigate and compare three other, practical attenuator designs which have been previously proposed: the piecewise-linear attenuator, the translating attenuator, and the double wedge attenuator. Methods: The authors pose and solve the optimization problems of minimizing the mean and peak variance subject to a fixed dose limit. For a perfect attenuator and mean variance minimization, this problem can be solved in simple, closed form. For other attenuator designs, the problem can be decomposed into separate problems for each view to greatly reduce the computational complexity. Peak variance minimization can be approximately solved using iterated, weighted mean variance (WMV) minimization. Also, the authors develop heuristics for the perfect and piecewise-linear attenuators which do not requirea priori knowledge of the patient anatomy. The authors compare these control algorithms on different types of dynamic attenuators using simulated raw data from forward projected DICOM files of a thorax and an abdomen. Results: The translating and double wedge attenuators reduce dose by an average of 30% relative to current techniques (bowtie filter with tube current modulation) without increasing peak variance. The 15-element piecewise-linear dynamic attenuator reduces dose by an average of 42%, and the perfect attenuator reduces dose by an average of 50%. Improvements in peak variance are several times larger than improvements in mean variance. Heuristic control eliminates the need for a prescan. For the piecewise-linear attenuator, the cost of heuristic control is an increase in dose of 9%. The proposed iterated WMV minimization produces results that are within a few percent of the true solution. Conclusions: Dynamic attenuators show potential for significant dose reduction. A wide class of dynamic attenuators can be accurately controlled using the described methods.

Hsieh, Scott S., E-mail: sshsieh@stanford.edu [Department of Radiology, Stanford University, Stanford, California 94305 and Department of Electrical Engineering, Stanford University, Stanford, California 94305 (United States); Pelc, Norbert J. [Department of Radiology, Stanford University, Stanford California 94305 and Department of Bioengineering, Stanford University, Stanford, California 94305 (United States)] [Department of Radiology, Stanford University, Stanford California 94305 and Department of Bioengineering, Stanford University, Stanford, California 94305 (United States)

2014-06-15T23:59:59.000Z

25

Mass without radiation: heavily obscured AGN, the X-ray Background and the Black Hole Mass Density  

E-Print Network (OSTI)

A recent revision of black hole scaling relations (Kormendy & Ho 2013), indicates that the local mass density in black holes should be increased by up to a factor of five with respect to previously determined values. The local black hole mass density is connected to the mean radiative efficiency of accretion through the time integral of the AGN volume density and a significant increase of the local black holes mass density would have interesting consequences on AGN accretion properties and demography. One possibility to explain a large black hole mass density is that most of the Black Hole growth is via radiatively inefficient channels such as super Eddington accretion, however, given the intrinsic degeneracies in the Soltan argument, this solution is not unique. Here we show how it is possible to accommodate a larger fraction of heavily buried, Compton thick AGN, without violating the limit imposed by the hard X-ray and mid-infrared backgrounds spectral energy density.

Comastri, A; Marconi, A; Risaliti, G; Salvati, M

2015-01-01T23:59:59.000Z

26

X-ray Properties of Intermediate-mass Black Holes in Active Galaxies  

E-Print Network (OSTI)

We present a pilot study of the X-ray properties of intermediate-mass (~10^5-10^6 M_sun) black holes in active galaxies using the Chandra X-ray telescope. Eight of the 10 active galaxies are detected with a significance of at least 3 sigma, with X-ray luminosities in the range L_(0.5-2 keV) ~ 10^41-10^43 ergs/s. The optical-to-X-ray flux ratios are consistent with expectations, given the known correlations between alpha_ox and ultraviolet luminosity, while a couple of objects appear to be anomalously X-ray weak. The range of 0.5--2 keV photon indices we measure, 1 X-ray spectral index. On the other hand, we do find evidence for a correlation between X-ray power-law slope and both X-ray luminosity and Eddington ratio, which may suggest that X-ray emission mechanisms weaken at high Eddington ratio. Such a weakening may explain the X-ray weakness of one of our most optically luminous objects.

Jenny E. Greene; Luis C. Ho

2006-08-02T23:59:59.000Z

27

Gamma-Ray Shielding Effectiveness of Some Alloys for Fusion Reactor Design  

Science Journals Connector (OSTI)

The gamma-ray shielding effectiveness of some oxide dispersion-strengthen (ODS) alloys by means of mass attenuation coefficients, mean free path, exposure buildup factors and energy absorption buildup factors hav...

Vishwanath P. Singh; M. E. Medhat; N. M. Badiger

2014-10-01T23:59:59.000Z

28

The Long Term Stability of Oscillations During Thermonuclear X-ray Bursts: Constraining the Binary X-ray Mass Function  

E-Print Network (OSTI)

We report on the long term stability of the millisecond oscillations observed with the Rossi X-ray Timing Explorer (RXTE) during thermonuclear X-ray bursts from the low mass X-ray binaries (LMXB) 4U 1728-34 and 4U 1636-53. We show that bursts from 4U 1728-34 spanning more than 1.5 years have observed asymptotic oscillation periods which are within 0.2 microsec. of each other, well within the magnitude which could be produced by the orbital motion of the neutron star in a typical LMXB. This stability implies a timescale to change the oscillation period of > 23,000 years, suggesting a highly stable process such as stellar rotation as the oscillation mechanism. We show that period offsets in three distinct bursts from 4U 1636-53 can be plausibly interpreted as due to orbital motion of the neutron star in this 3.8 hour binary system. We discuss the constraints on the mass function which can in principle be derived using this technique.

Tod E. Strohmayer; William Zhang; Jean H. Swank; Iosif Lapidus

1998-06-18T23:59:59.000Z

29

Mass and energy of erupting solar plasma observed with the X-Ray Telescope on Hinode  

E-Print Network (OSTI)

We investigate seven eruptive plasma observations by Hinode/XRT. Their corresponding EUV and/or white light CME features are visible in some events. Five events are observed in several passbands in X-rays, which allows the determination of the eruptive plasma temperature using a filter ratio method. We find that the isothermal temperatures vary from 1.6 to 10 MK. These temperatures are an average weighted toward higher temperature plasma. We determine the mass constraints of eruptive plasmas by assuming simplified geometrical structures of the plasma with isothermal plasma temperatures. This method provides an upper limit to the masses of the observed eruptive plasmas in X-ray passbands since any clumping causes the overestimation of the mass. For the other two events, we assume the temperatures are at the maximum temperature of the XRT temperature response function, which gives a lower limit of the masses. We find that the masses in XRT, ~3x10 13 - 5x10 14 g, are smaller in their upper limit than total masse...

Lee, Jin-Yi; Reeves, Katharine K; Moon, Yong-Jae; Kim, Kap-Sung

2014-01-01T23:59:59.000Z

30

X-ray Spectral Measurements of the Most Massive Stars: Stellar Wind Mass-Loss Rates and Shock Physics  

E-Print Network (OSTI)

X-ray Spectral Measurements of the Most Massive Stars: Stellar Wind Mass-Loss Rates and Shock/Themes: Significant technological advances in X-ray astronomy have driven discovery over the last few decades. New. The priorities at Swarthmore have allowed me to do careful work on the small number of X-ray spectral datasets

Cohen, David

31

E-Print Network 3.0 - attenuation correction application Sample...  

NLE Websites -- All DOE Office Websites (Extended Search)

SPECT imaging. Summary: the attenuation correction in the case of 3D attenuated ray transform with a parallel geometry. We suppose... be jointly acquired on dedicated systems....

32

Assessment of the possibilities of the dual-energy X-ray absorptiometry of multicomponent samples with variable content  

Science Journals Connector (OSTI)

Possibility of the employment of a linear coupling equation of mass attenuation coefficients for two energies for the density determination by dual-energy X-ray absorptiometry of multicomponent samples with varia...

N. A. Antropov; D. A. Karpov; Yu. Yu. Kryuchkov

2012-09-01T23:59:59.000Z

33

Hydrogen deficient donors in low-mass X-ray binaries  

E-Print Network (OSTI)

A number of X-ray binaries (neutron stars or black holes accreting from a companion star) have such short orbital periods that ordinary, hydrogen rich, stars do not fit in. Instead the mass-losing star must be a compact, evolved star, leading to the transfer of hydrogen deficient material to the neutron star. I discuss the current knowledge of these objects, with focus on optical spectroscopy.

Gijs Nelemans

2007-11-05T23:59:59.000Z

34

IR and UV Galaxies at z=0.6 -- Evolution of Dust Attenuation and Stellar Mass as Revealed by SWIRE and GALEX  

E-Print Network (OSTI)

We study dust attenuation and stellar mass of $\\rm z\\sim 0.6$ star-forming galaxies using new SWIRE observations in IR and GALEX observations in UV. Two samples are selected from the SWIRE and GALEX source catalogs in the SWIRE/GALEX field ELAIS-N1-00 ($\\Omega = 0.8$ deg$^2$). The UV selected sample has 600 galaxies with photometric redshift (hereafter photo-z) $0.5 \\leq z \\leq 0.7$ and NUV$\\leq 23.5$ (corresponding to $\\rm L_{FUV} \\geq 10^{9.6} L_\\sun$). The IR selected sample contains 430 galaxies with $f_{24\\mu m} \\geq 0.2$ mJy ($\\rm L_{dust} \\geq 10^{10.8} L_\\sun$) in the same photo-z range. It is found that the mean $\\rm L_{dust}/L_{FUV}$ ratios of the z=0.6 UV galaxies are consistent with that of their z=0 counterparts of the same $\\rm L_{FUV}$. For IR galaxies, the mean $\\rm L_{dust}/L_{FUV}$ ratios of the z=0.6 LIRGs ($\\rm L_{dust} \\sim 10^{11} L_\\sun$) are about a factor of 2 lower than local LIRGs, whereas z=0.6 ULIRGs ($\\rm L_{dust} \\sim 10^{12} L_\\sun$) have the same mean $\\rm L_{dust}/L_{FUV}$ ratios as their local counterparts. This is consistent with the hypothesis that the dominant component of LIRG population has changed from large, gas rich spirals at z$>0.5$ to major-mergers at z=0. The stellar mass of z=0.6 UV galaxies of $\\rm L_{FUV} \\leq 10^{10.2} L_\\sun$ is about a factor 2 less than their local counterparts of the same luminosity, indicating growth of these galaxies. The mass of z=0.6 UV lunmous galaxies (UVLGs: $\\rm L_{FUV} > 10^{10.2} L_\\sun$) and IR selected galaxies, which are nearly exclusively LIRGs and ULIRGs, is the same as their local counterparts.

C. Kevin Xu; David Shupe; Veronique Buat; Michael Rowan-Robinson; Jorge Iglesias-Páramo; Tsutomu T. Takeuchi; Tom A. Barlow; Tim Conrow; Fan Fang; Karl Forster; Peter G. Friedman; Eduardo Gonzales-Solares; Carol Lonsdale; D. Christopher Martin; Patrick Morrissey; Susan G. Neff; David Schiminovich; Mark Seibert; Todd Small; Gene Smith; Jason Surace; Ted Wyder

2007-01-31T23:59:59.000Z

35

Dust in the wind: the role of recent mass loss in long gamma-ray bursts  

E-Print Network (OSTI)

We study the late-time (t>0.5 days) X-ray afterglows of nearby (z3) X-ray emission that is inconsistent with forward shock synchrotron radiation associated with the afterglow. These explosions also show larger-than-average intrinsic absorption (NH_x,i >6d21 cm-2) and prompt gamma-ray emission with extremely long duration (T_90>1000 s). Chance association of these three rare properties (i.e. large NH_x,i, super-soft Gamma_x and extreme duration) in the same class of explosions is statistically unlikely. We associate these properties with the turbulent mass-loss history of the progenitor star that enriched and shaped the circum-burst medium. We identify a natural connection between NH_x,i Gamma_x and T_90 in these sources by suggesting that the late-time super-soft X-rays originate from radiation reprocessed by material lost to the environment by the stellar progenitor before exploding, (either in the form of a dust echo or as reprocessed radiation from a long-lived GRB remnant), and that the interaction of the...

Margutti, Raffaella; Guidorzi, C; Lazzati, D; Milisavljevic, D; Kamble, A; Laskar, T; Parrent, J; Gehrels, N C

2014-01-01T23:59:59.000Z

36

LONG-DURATION X-RAY FLASH AND X-RAY-RICH GAMMA-RAY BURSTS FROM LOW-MASS POPULATION III STARS  

SciTech Connect

Recent numerical simulations suggest that Population III (Pop III) stars were born with masses not larger than {approx}100 M {sub Sun} and typically {approx}40 M {sub Sun }. By self-consistently considering the jet generation and propagation in the envelope of these low-mass Pop III stars, we find that a Pop III blue supergiant star has the possibility of giving rise to a gamma-ray burst (GRB) even though it keeps a massive hydrogen envelope. We evaluate observational characteristics of Pop III GRBs and predict that Pop III GRBs have a duration of {approx}10{sup 5} s in the observer frame and a peak luminosity of {approx}5 Multiplication-Sign 10{sup 50} erg s{sup -1}. Assuming that the E {sub p}-L {sub p} (or E {sub p}-E {sub {gamma},iso}) correlation holds for Pop III GRBs, we find that the spectrum peak energy falls at approximately a few keV (or {approx}100 keV) in the observer frame. We discuss the detectability of Pop III GRBs by future satellite missions such as EXIST and Lobster. If the E {sub p}-E {sub {gamma},iso} correlation holds, we have the possibility to detect Pop III GRBs at z {approx} 9 as long-duration X-ray-rich GRBs by EXIST. Conversely, if the E {sub p}-L {sub p} correlation holds, we have the possibility to detect Pop III GRBs up to z {approx} 19 as long-duration X-ray flashes by Lobster.

Nakauchi, Daisuke; Kashiyama, Kazumi; Nakamura, Takashi [Department of Physics, Kyoto University, Oiwake-cho, Kitashirakawa, Sakyo-ku, Kyoto 606-8502 (Japan); Suwa, Yudai [Yukawa Institute for Theoretical Physics, Kyoto University, Oiwake-cho, Kitashirakawa, Sakyo-ku, Kyoto 606-8502 (Japan); Sakamoto, Takanori [Center for Research and Exploration in Space Science and Technology (CRESST), NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

2012-11-10T23:59:59.000Z

37

Heating and Ionization of the Primordial Intergalactic Medium by High Mass X-ray Binaries  

E-Print Network (OSTI)

We investigate the influence of High Mass X-ray Binaries on their high redshift environments. Using a one-dimensional radiative transfer code, we predict the ionization and temperature profiles surrounding a coeval stellar population, composed of main sequence stars and HMXBs, at various times after its formation. We consider both uniform density surroundings, and a cluster embedded in a 10^8 solar mass NFW halo. HMXBs in a constant density environment produce negligible enhanced ionization because of their high-energy SEDs and short lifetimes. In this case, HMXBs only marginally contribute to the local heating rate. For NFW profiles, radiation from main sequence stars cannot prevent the initially ionized volume from recombining since it is unable to penetrate the high density galactic core. However, HMXB photons stall recombinations behind the front, keeping it partially ionized for longer. The increased electron density in these partially ionized regions promotes further cooling, resulting in lower IGM temp...

Knevitt, Gillian; Power, Chris; Bolton, James

2014-01-01T23:59:59.000Z

38

Binary orbits as the driver of gamma-ray emission and mass ejection in classical novae  

E-Print Network (OSTI)

Classical novae are the most common astrophysical thermonuclear explosions, occurring on the surfaces of white dwarf stars accreting gas from companions in binary star systems. Novae typically expel ~10^(-4) solar masses of material at velocities exceeding 1,000 kilometres per second. However, the mechanism of mass ejection in novae is poorly understood, and could be dominated by the impulsive flash of thermonuclear energy, prolonged optically thick winds, or binary interaction with the nova envelope. Classical novae are now routinely detected in gigaelectronvolt gamma-ray wavelengths, suggesting that relativistic particles are accelerated by strong shocks in the ejecta. Here we report high-resolution radio imaging of the gamma-ray-emitting nova V959 Mon. We find that its ejecta were shaped by the motion of the binary system: some gas was expelled rapidly along the poles as a wind from the white dwarf, while denser material drifted out along the equatorial plane, propelled by orbital motion. At the interface ...

Chomiuk, Laura; Yang, Jun; O'Brien, T J; Paragi, Zsolt; Mioduszewski, Amy J; Beswick, R J; Cheung, C C; Mukai, Koji; Nelson, Thomas; Ribeiro, Valerio A R M; Rupen, Michael P; Sokoloski, J L; Weston, Jennifer; Zheng, Yong; Bode, Michael F; Eyres, Stewart; Roy, Nirupam; Taylor, Gregory B

2014-01-01T23:59:59.000Z

39

Signal Attenuation Curve for Different Surface Detector Arrays  

E-Print Network (OSTI)

Modern cosmic ray experiments consisting of large array of particle detectors measure the signals of electromagnetic or muon components or their combination. The correction for an amount of atmosphere passed is applied to the surface detector signal before its conversion to the shower energy. Either Monte Carlo based approach assuming certain composition of primaries or indirect estimation using real data and assuming isotropy of arrival directions can be used. Toy surface arrays of different sensitivities to electromagnetic and muon components are assumed in MC simulations to study effects imposed on attenuation curves for varying composition or possible high energy anisotropy. The possible sensitivity of the attenuation curve to the mass composition is also tested for different array types focusing on a future apparatus that can separate muon and electromagnetic component signals.

Vicha, J; Nosek, D; Ebr, J

2014-01-01T23:59:59.000Z

40

Radio and X-Ray Emission as Probes of Type IIP Supernovae and Red Supergiant Mass Loss  

E-Print Network (OSTI)

Type IIP (plateau) supernovae are thought to come from stars with initial mass about 8-25 solar masses that end their lives as red supergiants. The expected stellar end points can be found from evolutionary calculations and the corresponding mass loss properties at this point can be estimated from typical values for Galactic stars. The mass loss densities of observed supernovae can be estimated from observations of the thermal X-ray and radio synchrotron emission that result from the interaction of the supernova with the surrounding wind. Type IIP supernovae are expected to have energy-conserving interaction during typical times of observation. Because Type IIP supernovae have an extended period of high optical luminosity, Compton cooling can affect the radio emitting electrons, giving rise to a relatively flat radio light curve in the optically thin regime. Alternatively, a high efficiency of magnetic field production results in synchrotron cooling of the radio emitting electrons. Both the X-ray and radio luminosities are sensitive to the mass loss and initial masses of the progenitor stars, although the turn-on of radio emission is probably the best estimator of circumstellar density. Both the mass loss density and the variation of density with stellar mass are consistent with expectations for the progenitor stars deduced from direct observations of recent supernovae. Current observations are consistent with mass being the only parameter; observations of a supernova in a metal poor region might show how the mass loss depends on metallicity.

Roger A. Chevalier; Claes Fransson; Tanja K. Nymark

2005-09-15T23:59:59.000Z

Note: This page contains sample records for the topic "ray mass attenuation" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


41

The importance of muon information on primary mass discrimination of ultra-high energy cosmic rays  

E-Print Network (OSTI)

Several methods can be used to perform statistical inference of primary composition of cosmic rays measured with water Cerenkov detectors as those in use at the Pierre Auger Southern Observatory. In the present work we assess the impact of additional information about the number of muons in the air shower, on the problem of statistical primary mass discrimination. Several tools are studied, including neural networks, principal component analysis and traditional methods in current use in the field. For our case study we use hypothetical plastic scintillators as muon counters, buried at the side and outside the shade of the water Cerenkov tanks. The study is extended to protons and Fe nuclei impinging on an array with two different spacings, 750 and 1500 m and, therefore, suitable to the 1-10 EeV energy range. A prototype of such a detector is under construction.

D. Supanitsky; A. Tiba; G. Medina-Tanco; A. Etchegoyen; I. Allekotte; M. Gomez Berisso; V. de Souza; C. Medina; J. A. Ortiz; R. Shellard

2005-10-14T23:59:59.000Z

42

X-ray reflection in accreting stellar-mass black hole systems  

E-Print Network (OSTI)

The X-ray spectra of accreting stellar-mass black hole systems exhibit spectral features due to reflection, especially broad iron K alpha emission lines. We investigate the reflection by the accretion disc that can be expected in the high/soft state of such a system. First, we perform a self-consistent calculation of the reflection that results from illumination of a hot, inner portion of the disc with its atmosphere in hydrostatic equilibrium. Then we present reflection spectra for a range of illumination strengths and disc temperatures under the assumption of a constant-density atmosphere. Reflection by a hot accretion disc differs in important ways from that of a much cooler disc, such as that expected in an active galactic nucleus.

R. R. Ross; A. C. Fabian

2007-09-03T23:59:59.000Z

43

CLUSTERING BETWEEN HIGH-MASS X-RAY BINARIES AND OB ASSOCIATIONS IN THE MILKY WAY  

SciTech Connect

We present the first direct measurement of the spatial cross-correlation function of high-mass X-ray binaries (HMXBs) and active OB star-forming complexes in the Milky Way. This result relied on a sample containing 79 hard X-ray-selected HMXBs and 458 OB associations. Clustering between the two populations is detected with a significance above 7{sigma} for distances <1 kpc. Thus, HMXBs closely trace the underlying distribution of the massive star-forming regions that are expected to produce the progenitor stars of HMXBs. The average offset of 0.4 {+-} 0.2 kpc between HMXBs and OB associations is consistent with being due to natal kicks at velocities of the order of 100 {+-} 50 km s{sup -1}. The characteristic scale of the correlation function suggests an average kinematical age (since the supernova phase) of {approx}4 Myr for the HMXB population. Despite being derived from a global view of our Galaxy, these signatures of HMXB evolution are consistent with theoretical expectations as well as observations of individual objects.

Bodaghee, A.; Tomsick, J. A. [Space Sciences Laboratory, 7 Gauss Way, University of California, Berkeley, CA 94720 (United States); Rodriguez, J. [Laboratoire AIM, CEA/IRFU, Universite Paris Diderot, CNRS/INSU, CEA DSM/IRFU/SAp, Centre de Saclay, F-91191 Gif-sur-Yvette (France); James, J. B., E-mail: bodaghee@ssl.berkeley.edu [Dark Cosmology Centre, University of Copenhagen, Juliane Maries Vej 30, 2100 Copenhagen (Denmark)

2012-01-10T23:59:59.000Z

44

OBSERVATIONS OF THE HIGH-MASS X-RAY BINARY A 0535+26 IN QUIESCENCE  

SciTech Connect

We have analyzed three observations of the high-mass X-ray binary A 0535+26 performed by the Rossi X-Ray Timing Explorer (RXTE) three, five, and six months after the last outburst in 2011 February. We detect pulsations only in the second observation. The 3-20 keV spectra can be fit equally well with either an absorbed power law or absorbed thermal bremsstrahlung model. Reanalysis of two earlier RXTE observations made 4 yr after the 1994 outburst, original BeppoSAX observations 2 yr later, reanalysis of four EXOSAT observations made 2 yr after the last 1984 outburst, and a recent XMM-Newton observation in 2012 reveal a stacked, quiescent flux level decreasing from {approx}2 to <1 Multiplication-Sign 10{sup -11} erg cm{sup -2} s{sup -1} over 6.5 yr after outburst. The detection of pulsations during half of the quiescent observations would imply that accretion onto the magnetic poles of the neutron star continues despite the fact that the circumstellar disk may no longer be present. The accretion could come from material built up at the corotation radius or from an isotropic stellar wind.

Rothschild, Richard; Markowitz, Alex; Hemphill, Paul [University of California, San Diego, Center for Astrophysics and Space Sciences, 9500 Gilman Dr., La Jolla, CA 92093-0424 (United States); Caballero, Isabel [CEA Saclay, DSM/IRFU/SAp -UMR AIM (7158) CNRS/CEA/Universite P. Diderot, Orme des Merisiers, Bat. 709, F-91191 Gif-sur-Yvette (France); Pottschmidt, Katja [CRESST, UMBC, and NASA GSFC, Code 661, Greenbelt, MD 20771 (United States); Kuehnel, Matthias; Wilms, Joern [Dr. Karl-Remeis-Sternwarte and ECAP, Sternwartstr. 7, D-96049 Bamberg (Germany); Fuerst, Felix [Space Radiation Lab, MC 290-17 Cahill, California Institute of Technology, 1200 E. California Blvd, Pasadena, CA 91125 (United States); Doroshenko, Victor [Institut fuer Astronomie und Astrophysik, Universitaet Tuebingen, Sand 1, D-72076 Tuebingen (Germany); Camero-Arranz, Ascension, E-mail: rrothschild@ucsd.edu [Institut de Ciencies de l'Espai, (IEEC-CSIC), Campus UAB, Fac. de Ciencies, Torre C5, parell, 2a planta, E-08193 Barcelona (Spain)

2013-06-10T23:59:59.000Z

45

DISTRIBUTION OF HIGH-MASS X-RAY BINARIES IN THE MILKY WAY  

SciTech Connect

Observations of the high-energy sky, particularly with the INTEGRAL satellite, have quadrupled the number of supergiant X-ray binaries observed in the Galaxy and revealed new populations of previously hidden high-mass X-ray binaries (HMXBs), raising new questions about their formation and evolution. The number of detected HMXBs of different types is now high enough to allow us to carry out a statistical analysis of their distribution in the Milky Way. For the first time, we derive the distance and absorption of a sample of HMXBs using a spectral energy distribution fitting procedure, and we examine the correlation with the distribution of star-forming complexes (SFCs) in the Galaxy. We show that HMXBs are clustered with SFCs with a typical cluster size of 0.3 {+-} 0.05 kpc and a characteristic distance between clusters of 1.7 {+-} 0.3 kpc. Furthermore, we present an investigation of the expected offset between the position of spiral arms and HMXBs, allowing us to constrain age and migration distance due to supernova kick for 13 sources. These new methods will allow us to assess the influence of the environment on these high-energy objects with unprecedented reliability.

Coleiro, Alexis; Chaty, Sylvain, E-mail: alexis.coleiro@cea.fr, E-mail: chaty@cea.fr [Laboratoire AIM (UMR-E 9005 CEA/DSM-CNRS-Universite Paris Diderot), Irfu/Service d'Astrophysique, CEA-Saclay, F-91191 Gif-sur-Yvette Cedex (France)] [Laboratoire AIM (UMR-E 9005 CEA/DSM-CNRS-Universite Paris Diderot), Irfu/Service d'Astrophysique, CEA-Saclay, F-91191 Gif-sur-Yvette Cedex (France)

2013-02-20T23:59:59.000Z

46

Cyclotron line and wind studies of galactic high mass X- ray binaries  

E-Print Network (OSTI)

missions detected Gamma Ray Burst afterglows and discoveredUS launched the Swift Gamma-Ray Burst Mission (Gehrels etal. , 2004) to study gamma-ray bursts and their afterglows.

Suchy, Slawomir

2011-01-01T23:59:59.000Z

47

Low-Mass X-Ray Binary MAXI J1421-613 Observed by MAXI GSC and Swift XRT  

E-Print Network (OSTI)

Monitor of All sky X-ray Image (MAXI) discovered a new outburst of an X-ray transient source named MAXI J1421-613. Because of the detection of three X-ray bursts from the source, it was identified as a neutron star low-mass X-ray binary. The results of data analyses of the MAXI GSC and the Swift XRT follow-up observations suggest that the spectral hardness remained unchanged during the first two weeks of the outburst. All the XRT spectra in the 0.5-10 keV band can be well explained by thermal Comptonization of multi-color disk blackbody emission. The photon index of the Comptonized component is $\\approx$ 2, which is typical of low-mass X-ray binaries in the low/hard state. Since X-ray bursts have a maximum peak luminosity, it is possible to estimate the (maximum) distance from its observed peak flux. The peak flux of the second X-ray burst, which was observed by the GSC, is about 5 photons cm$^{-2}$ s$^{-1}$. By assuming a blackbody spectrum of 2.5 keV, the maximum distance to the source is estimated as 7 kpc...

Serino, Motoko; Ueda, Yoshihiro; Matsuoka, Masaru; Negoro, Hitoshi; Yamaoka, Kazutaka; Kennea, Jamie A; Fukushima, Kosuke; Nagayama, Takahiro

2015-01-01T23:59:59.000Z

48

The lowest-mass stellar black holes: catastrophic death of neutron stars in gamma-ray bursts  

E-Print Network (OSTI)

Mergers of double neutron stars are considered the most likely progenitors for short gamma-ray bursts. Indeed such a merger can produce a black hole with a transient accreting torus of nuclear matter (Lee & Ramirez-Ruiz 2007, Oechslin & Janka 2006), and the conversion of a fraction of the torus mass-energy to radiation can power a gamma-ray burst (Nakar 2006). Using available binary pulsar observations supported by our extensive evolutionary calculations of double neutron star formation, we demonstrate that the fraction of mergers that can form a black hole -- torus system depends very sensitively on the (largely unknown) maximum neutron star mass. We show that the available observations and models put a very stringent constraint on this maximum mass under the assumption that a black hole formation is required to produce a short gamma-ray burst in a double neutron star merger. Specifically, we find that the maximum neutron star mass must be within 2 - 2.5 Msun. Moreover, a single unambiguous measurement of a neutron star mass above 2.5 Msun would exclude a black hole -- torus central engine model of short gamma-ray bursts in double neutron star mergers. Such an observation would also indicate that if in fact short gamma-ray bursts are connected to neutron star mergers, the gamma-ray burst engine is best explained by the lesser known model invoking a highly magnetized massive neutron star (e.g., Usov 1992; Kluzniak & Ruderman 1998; Dai et al. 2006; Metzger, Quataert & Thompson 2007).

K. Belczynski; R. O'Shaughnessy; V. Kalogera; F. Rasio; R. Taam; T. Bulik

2008-04-16T23:59:59.000Z

49

The mass and the radius of the neutron star in the transient low mass X-ray binary SAX J1748.9-2021  

E-Print Network (OSTI)

.9-2021 Tolga G¨uver1 , Feryal ¨Ozel2,3 ABSTRACT We use time resolved spectroscopy of thermonuclear X-ray bursts of thermonuclear flashes on the neutron star surface (Galloway et al. 2008). In this paper, we use the time-resolved spectroscopy of a subsample of these thermonuclear bursts to determine the mass and radius of the neutron star

Yanikoglu, Berrin

50

Phase-resolved optical and X-ray spectroscopy of low-mass X-ray binary X1822-371  

E-Print Network (OSTI)

(Abridged) X1822-371 is the prototypical accretion disc corona X-ray source, a low-mass X-ray binary viewed at very high inclination, thereby allowing the disc structure and extended disc coronal regions to be visible. We study the structure of the accretion disc in X1822-371 by modelling the phase-resolved spectra both in optical and X-ray regime. We analyse high time resolution optical ESO/VLT spectra of X1822-371 to study the variability in the emission line profiles. In addition, we use data from XMM-Newton space observatory to study phase-resolved as well as high resolution X-ray spectra. We apply the Doppler tomography technique to reconstruct a map of the optical emission distribution in the system. We fit multi-component models to the X-ray spectra. We find that our results from both the optical and X-ray analysis can be explained with a model where the accretion disc has a thick rim in the region where the accretion stream impacts the disc. The behaviour of the H_beta line complex implies that some o...

Somero, A; Muhli, P; Charles, P; Vilhu, O

2012-01-01T23:59:59.000Z

51

X-ray radiography for container inspection  

DOE Patents (OSTI)

Arrangements of X-ray inspection systems are described for inspecting high-z materials in voluminous objects such as containers. Inspection methods may involve generating a radiographic image based on detected attenuation corresponding to a pulsed beams of radiation transmitted through a voluminous object. The pulsed beams of radiation are generated by a high-energy source and transmitted substantially downward along an incident angle, of approximately 1.degree. to 30.degree., to a vertical axis extending through the voluminous object. The generated radiographic image may be analyzed to detect on localized high attenuation representative of high-z materials and to discriminate high-z materials from lower and intermediate-z materials on the basis of the high density and greater attenuation of high-z material for higher energy (3-10 MeV) X-rays, and the compact nature of threatening masses of fissionable materials.

Katz, Jonathan I. (Clayton, MO); Morris, Christopher L. (Los Alamos, NM)

2011-06-07T23:59:59.000Z

52

Determination of self-absorption corrections by computation in routine gamma-ray spectrometry for typical environmental samples  

SciTech Connect

A simple and practical method has been developed to quickly calculate self-absorption corrections and mass attenuation coefficients, {mu}/p, in common environmental samples being analyzed by gamma-ray spectrometry. The method involves using a sample computer program and estimates of the elemental compositions of typical environmental samples. The use of this method eliminates the need for gamma-ray-transmission measurements of individual samples, as well as expensive and time consuming elemental analyses of routine samples. The calculated percent attenuation of the beam through various samples, as determined by this method, agrees very well with experimentally measured values of percent attenuation.

Oresegun, M.O. [Univ. of Ibadan (Nigeria); Decker, K.M.; Sanderson, C.G. [Environmental Measurements Lab., New York, NY (United States)

1993-12-31T23:59:59.000Z

53

The effect of accretion on the measurement of neutron star mass and radius in the low-mass X-ray binary 4U 1608-52  

E-Print Network (OSTI)

Spectral measurements of thermonuclear (type-I) X-ray bursts from low mass X-ray binaries have been used to measure neutron star (NS) masses and radii. A number of systematic issues affect such measurements and have raised concerns as to the robustness of the methods. We present analysis of the X-ray emission from bursts observed from 4U 1608-52 at various persistent fluxes. We find a strong dependence of the burst properties on the flux and spectral hardness of the persistent emission before burst. Bursts occurring during the low-accretion rate (hard) state exhibit evolution of the black body normalisation consistent with the theoretical predictions of NS atmosphere models. However, bursts occurring during the high-accretion rate (soft) state show roughly constant normalisation, which is inconsistent with the NS atmosphere models and therefore these bursts cannot be easily used to determine NS parameters. We analyse the hard-state burst to put the lower limit on the neutron star radius in 4U 1608-52 of 13 km...

Poutanen, Juri; Kajava, Jari J E; Latvala, Outi-Marja; Galloway, Duncan; Kuulkers, Erik; Suleimanov, Valery

2014-01-01T23:59:59.000Z

54

Analytical model of strange star in the low-mass X-ray binary 4U 1820-30  

E-Print Network (OSTI)

In this article, we have proposed a model for a realistic strange star under Tolman VII metric\\citep{Tolman1939}. Here the field equations are reduced to a system of three algebraic equations for anisotropic pressure. Mass, central density and surface density of strange star in the low-mass X-ray binary 4U 1820-30 has been matched with the observational data according to our model. Strange materials clearly satisfies the stability condition (i.e. sound velocities < 1) and TOV-equation. Here also surface red shift of the star has been found to be within reasonable limit.

Mehedi Kalam; Farook Rahaman; Sajahan Molla; Md. Abdul Kayum Jafry; Sk. Monowar Hossein

2014-07-19T23:59:59.000Z

55

Measuring mass-loss rates and constraining shock physics using X-ray line profiles of O stars from the Chandra archive  

Science Journals Connector (OSTI)

......Measuring mass-loss rates and constraining shock physics using X-ray line...sight lines that pass through the densest...wind mass-loss rate, we tabulated...low mass-loss rates: (1) the line...missing some crucial physics; (2) processes......

David H. Cohen; Emma E. Wollman; Maurice A. Leutenegger; Jon O. Sundqvist; Alex W. Fullerton; Janos Zsargó; Stanley P. Owocki

2014-01-01T23:59:59.000Z

56

The Multi-Scale Mass Transfer Processes Controlling Natural Attenuation and Engineered Remediation: An IFC Focused on Hanford’s 300 Area Uranium Plume Quality Assurance Project Plan  

SciTech Connect

The purpose of the project is to conduct research at an Integrated Field-Scale Research Challenge Site in the Hanford Site 300 Area, CERCLA OU 300-FF-5 (Figure 1), to investigate multi-scale mass transfer processes associated with a subsurface uranium plume impacting both the vadose zone and groundwater. The project will investigate a series of science questions posed for research related to the effect of spatial heterogeneities, the importance of scale, coupled interactions between biogeochemical, hydrologic, and mass transfer processes, and measurements/approaches needed to characterize a mass-transfer dominated system. The research will be conducted by evaluating three (3) different hypotheses focused on multi-scale mass transfer processes in the vadose zone and groundwater, their influence on field-scale U(VI) biogeochemistry and transport, and their implications to natural systems and remediation. The project also includes goals to 1) provide relevant materials and field experimental opportunities for other ERSD researchers and 2) generate a lasting, accessible, and high-quality field experimental database that can be used by the scientific community for testing and validation of new conceptual and numerical models of subsurface reactive transport.

Fix, N. J.

2008-01-31T23:59:59.000Z

57

Radio and X-Ray Emission as Probes of Type IIP Supernovae and Red Supergiant Mass Loss  

E-Print Network (OSTI)

Type IIP (plateau) supernovae are thought to come from stars with initial mass about 8-25 solar masses that end their lives as red supergiants. The expected stellar end points can be found from evolutionary calculations and the corresponding mass loss properties at this point can be estimated from typical values for Galactic stars. The mass loss densities of observed supernovae can be estimated from observations of the thermal X-ray and radio synchrotron emission that result from the interaction of the supernova with the surrounding wind. Type IIP supernovae are expected to have energy-conserving interaction during typical times of observation. Because Type IIP supernovae have an extended period of high optical luminosity, Compton cooling can affect the radio emitting electrons, giving rise to a relatively flat radio light curve in the optically thin regime. Alternatively, a high efficiency of magnetic field production results in synchrotron cooling of the radio emitting electrons. Both the X-ray and radio lu...

Chevalier, R A; Nymark, T K; Chevalier, Roger A.; Fransson, Claes; Nymark, Tanja K.

2006-01-01T23:59:59.000Z

58

Variable laser attenuator  

DOE Patents (OSTI)

The disclosure relates to low loss, high power variable attenuators comprising one or more transmissive and/or reflective multilayer dielectric filters. The attenuator is particularly suitable to use with unpolarized lasers such as excimer lasers. Beam attenuation is a function of beam polarization and the angle of incidence between the beam and the filter and is controlled by adjusting the angle of incidence the beam makes to the filter or filters. Filters are selected in accordance with beam wavelength. 9 figs.

Foltyn, S.R.

1987-05-29T23:59:59.000Z

59

Did a gamma-ray burst initiate the late Ordovician mass extinction?  

E-Print Network (OSTI)

Gamma-ray bursts (GRBs) produce a flux of radiation detectable across the observable Universe. A GRB within our own galaxy could do considerable damage to the Earth's biosphere; rate estimates suggest that a dangerously near GRB should occur...

Melott, Adrian L.; Lieberman, Bruce S.; Laird, C. M.; Martin, Larry D.; Medvedev, Mikhail V.; Thomas, B. C.; Cannizzo, J. K.; Gehrels, N.; Jackman, C. H.

2004-01-01T23:59:59.000Z

60

Natural Attenuation of Zinc Pollution in Smelter-Affected Soil  

E-Print Network (OSTI)

at contaminated sites (natural attenuation of pollution), and (iii) formulating effective remediation strategies material). The advent of X-ray microprobes(4)madepossibletheidentificationofsecondary forms, produced in contact with pore waters. Using micro X-ray fluorescence (µ-XRF) and extended X-ray absorption fine

Note: This page contains sample records for the topic "ray mass attenuation" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


61

Multi-Scale Mass Transfer Processes Controlling Natural Attenuation and Engineered Remediation: An IFRC Focused on Hanford’s 300 Area Uranium Plume  

SciTech Connect

The Integrated Field-Scale Subsurface Research Challenge (IFRC) at the Hanford Site 300 Area uranium (U) plume addresses multi-scale mass transfer processes in a complex hydrogeologic setting where groundwater and riverwater interact. A series of forefront science questions on mass transfer are posed for research which relate to the effect of spatial heterogeneities; the importance of scale; coupled interactions between biogeochemical, hydrologic, and mass transfer processes; and measurements and approaches needed to characterize and model a mass-transfer dominated system. The project was initiated in February 2007, with CY 2007 and CY 2008 progress summarized in preceding reports. The site has 35 instrumented wells, and an extensive monitoring system. It includes a deep borehole for microbiologic and biogeochemical research that sampled the entire thickness of the unconfined 300 A aquifer. Significant, impactful progress has been made in CY 2009 with completion of extensive laboratory measurements on field sediments, field hydrologic and geophysical characterization, four field experiments, and modeling. The laboratory characterization results are being subjected to geostatistical analyses to develop spatial heterogeneity models of U concentration and chemical, physical, and hydrologic properties needed for reactive transport modeling. The field experiments focused on: (1) physical characterization of the groundwater flow field during a period of stable hydrologic conditions in early spring, (2) comprehensive groundwater monitoring during spring to characterize the release of U(VI) from the lower vadose zone to the aquifer during water table rise and fall, (3) dynamic geophysical monitoring of salt-plume migration during summer, and (4) a U reactive tracer experiment (desorption) during the fall. Geophysical characterization of the well field was completed using the down-well Electrical Resistance Tomography (ERT) array, with results subjected to robust, geostatistically constrained inversion analyses. These measurements along with hydrologic characterization have yielded 3D distributions of hydraulic properties that have been incorporated into an updated and increasingly robust hydrologic model. Based on significant findings from the microbiologic characterization of deep borehole sediments in CY 2008, down-hole biogeochemistry studies were initiated where colonization substrates and spatially discrete water and gas samplers were deployed to select wells. The increasingly comprehensive field experimental results, along with the field and laboratory characterization, are leading to a new conceptual model of U(VI) flow and transport in the IFRC footprint and the 300 Area in general, and insights on the microbiological community and associated biogeochemical processes. A significant issue related to vertical flow in the IFRC wells was identified and evaluated during the spring and fall field experimental campaigns. Both upward and downward flows were observed in response to dynamic Columbia River stage. The vertical flows are caused by the interaction of pressure gradients with our heterogeneous hydraulic conductivity field. These impacts are being evaluated with additional modeling and field activities to facilitate interpretation and mitigation. The project moves into CY 2010 with ambitious plans for a drilling additional wells for the IFRC well field, additional experiments, and modeling. This research is part of the ERSP Hanford IFRC at Pacific Northwest National Laboratory.

Zachara, John M.; Bjornstad, Bruce N.; Christensen, John N.; Conrad, Mark E.; Fredrickson, Jim K.; Freshley, Mark D.; Haggerty, Roy; Hammon, Glenn; Kent, Douglas B.; Konopka, Allan; Lichtner, Peter C.; Liu, Chongxuan; McKinley, James P.; Murray, Christopher J.; Rockhold, Mark L.; Rubin, Yoram; Vermeul, Vincent R.; Versteeg, Roelof J.; Ward, Anderson L.; Zheng, Chunmiao

2010-02-01T23:59:59.000Z

62

The Prospects for Constraining Dark Energy withFuture X-ray Cluster Gas Mass Fraction Measurements  

SciTech Connect

We examine the ability of a future X-ray observatory, with capabilities similar to those planned for the Constellation-X mission, to constrain dark energy via measurements of the cluster X-ray gas mass fraction, fgas. We find that fgas measurements for a sample of {approx}500 hot (kT{approx}> 5keV), X-ray bright, dynamically relaxed clusters, to a precision of {approx}5 percent, can be used to constrain dark energy with a Dark Energy Task Force (DETF; Albrecht et al. 2006) figure of merit of 20-50. Such constraints are comparable to those predicted by the DETF for other leading, planned 'Stage IV' dark energy experiments. A future fgas experiment will be preceded by a large X-ray or SZ survey that will find hot, X-ray luminous clusters out to high redshifts. Short 'snapshot' observations with the new X-ray observatory should then be able to identify a sample of {approx}500 suitably relaxed systems. The redshift, temperature and X-ray luminosity range of interest has already been partially probed by existing X-ray cluster surveys which allow reasonable estimates of the fraction of clusters that will be suitably relaxed for fgas work to be made; these surveys also show that X-ray flux contamination from point sources is likely to be small for the majority of the targets of interest. Our analysis uses a Markov Chain Monte Carlo method which fully captures the relevant degeneracies between parameters and facilities the incorporation of priors and systematic uncertainties in the analysis. We explore the effects of such uncertainties, for scenarios ranging from optimistic to pessimistic. We conclude that the fgas experiment offers a competitive and complementary approach to the best other large, planned dark energy experiments. In particular, the fgas experiment will provide tight constraints on the mean matter and dark energy densities, with a peak sensitivity for dark energy work at redshifts midway between those of supernovae and baryon acoustic oscillation/weak lensing/cluster number counts experiments. In combination, these experiments should enable a precise measurement of the evolution of dark energy.

Rapetti, David; Allen, Steven W.

2007-10-15T23:59:59.000Z

63

The secondary stars in cataclysmic variables and low-mass X-ray binaries  

Science Journals Connector (OSTI)

......detailed models with the latest input physics, and the thin; solid...most up-to-date stellar input physics for low-mass stars...until the minimum mass for nuclear fusion is reached and the secondary...Parameters in bold face were those input to the Monte Carlo simulator......

D. A. Smith; V. S. Dhillon

1998-12-11T23:59:59.000Z

64

Population of persistent high-mass X-ray binaries in the Milky Way  

Science Journals Connector (OSTI)

......shape of the LF of wind-fed HMXBs demonstrates...rather than the stellar mass distribution (see...that on the average map, obtained with the...receive their systemic velocity during supernova explosions...applicable to the wind-fed population...simply depends on the mass flow, intercepted......

A. A. Lutovinov; M. G. Revnivtsev; S. S. Tsygankov; R. A. Krivonos

2013-01-01T23:59:59.000Z

65

E-Print Network 3.0 - attenuates paraquat-induced lung Sample...  

NLE Websites -- All DOE Office Websites (Extended Search)

area of the lung using X-ray attenuation data... Lung Assessment Using Computer Tomography A software program that determines the weight, tissue... composition and various...

66

Bowen blend echo-tomography of low mass X-ray binaries  

E-Print Network (OSTI)

We present simultaneous high time resolution (1-10 Hz) X-ray and optical observations of the persistent LMXBs Sco X-1 and V801 Ara(=4U 1636-536). In the case of Sco X-1 we find that the Bowen/HeII emission lags the X-ray light-curves with a light travel time of ~11-16s which is consistent with reprocessing in the donor star. We also present the detection of three correlated X-ray/optical bursts in V801 ara. Although this latter project is still in progress our preliminary results obtained by subtracting the Continuum light-curve from the Bowen/HeII data provide evidence of orbital phase dependent echoes from the companion star.

T. Muñoz-Darias; I. G. Martinez-Pais; J. Casares; R. Cornelisse; V. S. Dhillon; T. R. Marsh; D. Steeghs; K. O'Brien; P. A. Charles; M. Still

2007-09-21T23:59:59.000Z

67

A search for iron emission lines in the Chandra X-ray spectra of neutron star low-mass X-ray binaries  

E-Print Network (OSTI)

While iron emission lines are well studied in black hole systems, both in X-ray binaries and Active Galactic Nuclei, there has been less of a focus on these lines in neutron star low-mass X-ray binaries (LMXBs). However, recent observations with Suzaku and XMM-Newton have revealed broad asymmetric iron line profiles in 4 neutron star LMXBs, confirming an inner disk origin for these lines in neutron star systems. Here, we present a search for iron lines in 6 neutron star LMXBs. For each object we have simultaneous Chandra and RXTE observations at 2 separate epochs, allowing for both a high resolution spectrum, as well as broadband spectral coverage. Out of the six objects in the survey, we only find significant iron lines in two of the objects, GX 17+2 and GX 349+2. However, we cannot rule out that there are weak, broad lines present in the other sources. The equivalent width of the line in GX 17+2 is consistent between the 2 epochs, while in GX 349+2 the line equivalent width increases by a factor of ~3 between epochs as the source flux decreases by a factor of 1.3. This suggests that the disk is highly ionized, and the line is dominated by recombination emission. We find that there appears to be no specific locations in the long-term hardness-intensity diagrams where iron emission lines are formed, though more sources and further observations are required.

E. M. Cackett; J. M. Miller; J. Homan; M. van der Klis; W. H. G. Lewin; M. Mendez; J. Raymond; D. Steeghs; R. Wijnands

2008-09-18T23:59:59.000Z

68

Global Simulations of the Interaction of Microquasar Jets with a Stellar Wind in High-Mass X-ray Binaries  

E-Print Network (OSTI)

Jets powered by high-mass X-ray binaries must traverse the powerful wind of the companion star. We present the first global 3D simulations of jet-wind interaction in high-mass X-ray binaries. We show that the wind momentum flux intercepted by the jet can lead to significant bending of the jet and that jets propagating through a spherical wind will be bent to an asymptotic angle $\\psi_{\\infty}$. We derive simple expressions for $\\psi_{\\infty}$ as a function of jet power and wind thrust. For known wind parameters, measurements of $\\psi_{\\infty}$ can be used to constrain the jet power. In the case of Cygnus X-1, the lack of jet precession as a function of orbital phase observed by the VLBA can be used to put a lower limit on the jet power of $L_{\\rm jet} \\gtrsim 10^{36}\\,{\\rm ergs\\,s^{-1}}$. We further discuss the case where the initial jet is inclined relative to the binary orbital axis. We also analyze the case of Cygnus X-3 and show that jet bending is likely negligible unless the jet is significantly less po...

Yoon, Doosoo

2015-01-01T23:59:59.000Z

69

X-rays from low and intermediate mass stars Jan Robrade  

E-Print Network (OSTI)

-Newton, Chandra) mod. active stars log LX/Lbol -4, TXqq = 1 - 5 MK quasi-quiescent X-ray emission, log LX/Lbol -3.0 � � � - 5.0 strong flares with hot plasma ( 10 MK) frequent #12;Ultracool Dwarfs - X of Altair and Alderamin A7 IV-V, M = 1.8/2.0 M, age: 1.2/0.8 Gyr ultra-fast rotators, Vsini 220/280 km

Robrade, Jan

70

A 400 solar mass black hole in the Ultraluminous X-ray source M82 X-1 accreting close to its Eddington limit  

E-Print Network (OSTI)

M82 X-1, the brightest X-ray source in the galaxy M82, has been thought to be an intermediate-mass black hole (100 to 10,000 solar masses) because of its extremely high luminosity and variability characteristics, although some models suggest that its mass may be only about 20 solar masses. The previous mass estimates were based on scaling relations that use low-frequency characteristic timescales which have large intrinsic uncertainties. For stellar-mass black holes, we know that the high-frequency quasi-periodic oscillations (100-450 hertz) in the X-ray emission that occur in a 3:2 frequency ratio are stable and scale in frequency inversely with black hole mass with a reasonably small dispersion. The discovery of such stable oscillations thus potentially offers an alternative and less ambiguous means of mass determination for intermediate-mass black holes, but has hitherto not been realized. Here we report stable, twin-peak (3:2 frequency ratio) X-ray quasi-periodic oscillations from M82 X-1 at frequencies o...

Pasham, Dheeraj R; Mushotzky, Richard F

2015-01-01T23:59:59.000Z

71

Attenuator And Conditioner  

DOE Patents (OSTI)

An apparatus and method of attenuating and/or conditioning optical energy for an optical transmitter, receiver or transceiver module is disclosed. An apparatus for attenuating the optical output of an optoelectronic connector including: a mounting surface; an array of optoelectronic devices having at least a first end; an array of optical elements having at least a first end; the first end of the array of optical elements optically aligned with the first end of the array of optoelectronic devices; an optical path extending from the first end of the array of optoelectronic devices and ending at a second end of the array of optical elements; and an attenuator in the optical path for attenuating the optical energy emitted from the array of optoelectronic devices. Alternatively, a conditioner may be adapted in the optical path for conditioning the optical energy emitted from the array of optoelectronic devices.

Anderson, Gene R. (Albuquerque, NM); Armendariz, Marcelino G. (Albuquerque, NM); Carson, Richard F. (Albuquerque, NM); Bryan, Robert P. (Albuquerque, NM); Duckett, III, Edwin B. (Albuquerque, NM); Kemme, Shanalyn Adair (Albuquerque, NM); McCormick, Frederick B. (Albuquerque, NM); Peterson, David W. (Sandia Park, NM)

2006-04-04T23:59:59.000Z

72

Attenuation Based Remedies  

Energy.gov (U.S. Department of Energy (DOE))

The mission of the Attenuation Based Remedies in the Subsurface Applied Field Research Initiative is to seek holistic solutions to DOE’s groundwater contamination problems that consider not only...

73

Seismic viscoelastic attenuation Submitted to  

E-Print Network (OSTI)

Seismic viscoelastic attenuation Submitted to: Encyclopedia of Solid Earth Geophysics Harsh Gupta-3046 USA E-mail: vernon.cormier@uconn.edu Tel: 860-486-3547 Fax: 860-486-3346 #12;SEISMIC VISCOELASTIC ATTENUATION Synonyms Seismic intrinsic attenuation Definitions Linear viscoelastic attenuation. The loss

Cormier, Vernon F.

74

SHORT GAMMA-RAY BURSTS: THE MASS OF THE ACCRETION DISK AND THE INITIAL RADIUS OF THE OUTFLOW  

SciTech Connect

In this work, we estimate the accretion-disk mass in the specific scenario of binary-neutron-star merger with current observational data. Assuming that the outflows of short gamma-ray bursts (GRBs) are driven via neutrino-antineutrino annihilation we estimate the disk mass of about half of short bursts in the sample to be {approx}0.01-0.1 M{sub sun}, in agreement with that obtained in the numerical simulations. Massive disks ({approx}several 0.1 M{sub sun}) found in some other short GRBs may point to the more efficient magnetic process of extracting energy or the neutron star and black hole binary progenitor. Our results suggest that some short bursts may be really due to the coalescence of double neutron stars and are promising gravitational wave radiation sources. For future short GRBs with simultaneous gravitational-wave detections, the disk mass may be reliably inferred and the validity of our approach will be tested. We also propose a method to constrain the initial radius of a baryonic outflow where it is launched (R{sub 0}) without the need of identifying an ideal thermal spectrum component. We then apply it to GRB 090510 and get R{sub 0} {approx}< 6.5 x 10{sup 6}({Gamma}{sub ph}/2000){sup -4} cm, suggesting that the central engine is a black hole with a mass <22 M{sub sun}({Gamma}{sub ph}/2000){sup -4}, where {Gamma}{sub ph} is the bulk Lorentz factor of the outflow at the photospheric radius.

Fan Yizhong; Wei Daming, E-mail: yzfan@pmo.ac.cn, E-mail: dmwei@pmo.ac.cn [Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008 (China)

2011-09-20T23:59:59.000Z

75

SPITZER OBSERVATIONS OF BLACK HOLE LOW-MASS X-RAY BINARIES: ASSESSING THE NON-STELLAR INFRARED COMPONENT  

SciTech Connect

We have combined ground-based optical and near-infrared data with Spitzer Space Telescope mid-infrared data for five black hole (BH) soft X-ray transients (SXTs) in order to determine the levels of near- and mid-infrared emission from sources other than the secondary star. Mid-infrared emission from an accretion disk, circumbinary dust, and/or a jet could act as sources of near-infrared contamination, thereby diluting ellipsoidal variations of the secondary star and affecting determined BH mass estimates. Based on optical to mid-infrared spectral energy distribution modeling of the five SXTs along with the prototype, V616 Mon, we detected mid-infrared excesses in half of the systems, and suggest that the excesses detected from these systems arise from non-thermal synchrotron jets rather than circumbinary dust disks.

Gelino, Dawn M. [NASA Exoplanet Science Institute, California Institute of Technology, Pasadena, CA 91125 (United States); Gelino, Christopher R. [Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, CA 91125 (United States); Harrison, Thomas E., E-mail: dawn@ipac.caltech.ed [New Mexico State University, Las Cruces, NM 88003 (United States)

2010-07-20T23:59:59.000Z

76

The effects of coronal mass ejection on galactic cosmic rays in the high latitude heliosphere: Observations from Ulysses` first orbit  

SciTech Connect

During its first solar orbit the Ulysses spacecraft detected several coronal mass ejections (CMEs) at high heliographic latitudes. The authors present first observations on the effects of these high latitude CMEs on galactic cosmic rays (GCRs) using measurements from the Kiel Electron Telescope (KET) which is part of the Cosmic Ray and Solar Particle Investigation (COSPIN) experiment, the Los Alamos SWOOPS (Solar Wind Observations Over the Poles of the Sun) experiment and the magnetic field experiments. They find the passage of these CMEs over the spacecraft to be associated with short term decreases of GCR intensities The relatively weak shocks in these events, driven by the CMEs` over-expansion, had no strong influence on the GCRs. The intensity minimums of GCRs occurred on closed magnetic field lines inside the CMEs themselves as indicated by bidirectional fluxes of suprathermal electrons. Short episodes of intensity increases of GCRs inside CMEs at times when the bidirectional fluxes of suprathermal electrons disappeared, can be interpreted as evidence that GCRs can easily access the interior of those CMEs in which open magnetic field lines are embedded.

Bothmer, V.; Heber, B.; Kunow, H.; Mueller-Mellin, R.; Wibberenz, G. [Univ. of Kiel (Germany). Institut fuer Kernphysik; Gosling, J.T. [Los Alamos National Lab., NM (United States); Balogh, A. [Imperial College, London (United Kingdom). Blackett Lab.; Raviart, A. [CEA, Gif-sur-Yvette (France). Service d`Astrophysique; Paizis, C. [Univ. di Milano (Italy). Istituto di Fisica Cosmica CNR

1997-10-01T23:59:59.000Z

77

Superorbital Periodic Modulation in Wind-Accretion High-Mass X-ray Binaries from Swift BAT Observations  

E-Print Network (OSTI)

We report the discovery using data from the Swift Burst Alert Telescope (BAT) of superorbital modulation in the wind-accretion supergiant high-mass X-ray binaries 4U 1909+07 (= X 1908+075), IGR J16418-4532, and IGR J16479-4514. Together with already known superorbital periodicities in 2S 0114+650 and IGR J16493-4348, the systems exhibit a monotonic relationship between superorbital and orbital periods. These systems include both supergiant fast X-ray transients (SFXTs) and classical supergiant systems, and have a range of inclination angles. This suggests an underlying physical mechanism which is connected to the orbital period. In addition to these sources with clear detections of superorbital periods, IGR J16393-4643 (= AX J16390.4-4642) is identified as a system that may have superorbital modulation due to the coincidence of low-amplitude peaks in power spectra derived from BAT, RXTE PCA, and INTEGRAL light curves. 1E 1145.1-6141 may also be worthy of further attention due to the amount of low-frequency mo...

Corbet, Robin H D

2013-01-01T23:59:59.000Z

78

Isotopic ratios and effective power determined by gamma-ray spectroscopy vs mass spectroscopy for molten salt extraction residues  

SciTech Connect

Impure plutonium metal is routinely processed by molten salt extraction (MSE) to reduce the amount of americium in the metal product. Throughput at various facilities where similar processes are performed has made it essential to evaluate uncertainties and possible discrepancies in the analyses of these difficult MSE materials. In an effort to evaluate the plutonium isotopic ratios and americium concentrations obtained from gamma-ray spectral data analyzed by the computer code GRPAUT, measurements were made on ten MSE salts as received and after pulverization and blending. These results were then compared to the specific powers obtained from isotopic ratios determined by mass spectrometry on these same ten samples. Americium values ranged from a few thousand parts-per-million of total plutonium to greater than 50,000 ppM. Our results indicate a small discrepancy between specific powers as determined by GRPAUT on as received'' vs pulverized and blended MSE salts. The specific powers obtained via GRPAUT on the pulverized salts agree somewhat better with specific powers obtained from the mass spectroscopy data. This work may indicate that a small discrepancy exists in the specific powers by using GRPAUT on heterogeneous, high americium samples. 5 refs., 6 tabs.

Longmire, V.L.; Cremers, T.L.; Sedlacek, W.A.; Long, S.M.; Scarborough, A.M.; Hurd, J.R.

1990-01-01T23:59:59.000Z

79

The galaxy cluster X-ray luminosity--gravitational mass relation in the light of the WMAP 3rd year data  

E-Print Network (OSTI)

The 3rd year WMAP results mark a shift in best fit values of cosmological parameters compared to the 1st year data and the concordance cosmological model. We test the consistency of the new results with previous constraints on cosmological parameters from the HIFLUGCS galaxy cluster sample and the impact of this shift on the X-ray luminosity-gravitational mass relation. The measured X-ray luminosity function combined with the observed luminosity-mass relation are compared to mass functions predicted for given cosmological parameter values. The luminosity function and luminosity-mass relation derived previously from HIFLUGCS are in perfect agreement with mass functions predicted using the best fit parameter values from the 3rd year WMAP data (OmegaM=0.238, sigma8=0.74) and inconsistent with the concordance cosmological model (OmegaM=0.3, sigma8=0.9), assuming a flat Universe. Trying to force consistency with the concordance model requires artificially decreasing the normalization of the luminosity-mass relation by a factor of 2. The shift in best fit values for OmegaM and sigma8 has a significant impact on predictions of cluster abundances. The new WMAP results are now in perfect agreement with previous results on the OmegaM-sigma8 relation determined from the mass function of HIFLUGCS clusters and other X-ray cluster samples (the ``low cluster normalization''). We conclude that - unless the true values of OmegaM and sigma8 differ significantly from the 3rd year WMAP results - the luminosity-mass relation is well described by their previous determination from X-ray observations of clusters, with a conservative upper limit on the bias factor of 1.5. These conclusions are currently being tested in a complete follow-up program of all HIFLUGCS clusters with Chandra and XMM-Newton.

Thomas H. Reiprich

2006-05-22T23:59:59.000Z

80

ASTRO-H White Paper - Low-mass X-ray Binaries  

E-Print Network (OSTI)

There is still 10-20% uncertainty on the neutron star (NS) mass-radius relation. These uncertainties could be reduced by an order of magnitude through an unambiguous measure of M/R from the surface redshift of a narrow line, greatly constraining the Equation of State for ultra-dense material. It is possible that the SXS on ASTRO-H can detect this from an accreting neutron star with low surface velocity in the line of sight i.e. either low inclination or low spin. Currently there is only one known low inclination LMXB, Ser X-1, and one known slow spin LMXB, J17480-2446 in Terzan 5. Ser X-1 is a persistent source which is always in the soft state (banana branch), where the accreting material should form a equatorial belt around the neutron star. A pole-on view should then allow the NS surface to be seen directly. A 100 ks observation should allow us to measure M/R if there are any heavy elements in the photosphere at the poles. Conversely, J17480-2446 in Terzan 5 is a transient accretion powered millisecond pul...

Done, C; Cackett, E; Herder, J W den; Dotani, T; Enoto, T; Ferrigno, C; Kallman, T; Kohmura, T; Laurent, P; Miller, J; Mineshige, S; Mori, H; Nakazawa, K; Paerels, F; Sakurai, S; Soong, Y; Sugita, S; Takahashi, H; Tamagawa, T; Tanaka, Y; Terada, Y; Uno, S

2014-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "ray mass attenuation" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


81

Tritium Attenuation by Distillation  

SciTech Connect

The objective of this study was to determine how a 100 Area distillation system could be used to reduce to a satisfactory low value the tritium content of the dilute moderator produced in the 100 Area stills, and whether such a tritium attenuator would have sufficient capacity to process all this material before it is sent to the 400 Area for reprocessing.

Wittman, N.E.

2001-07-31T23:59:59.000Z

82

Radiation attenuation by lead and nonlead materials used in radiation shielding garments  

SciTech Connect

The attenuating properties of several types of lead (Pb)-based and non-Pb radiation shielding materials were studied and a correlation was made of radiation attenuation, materials properties, calculated spectra and ambient dose equivalent. Utilizing the well-characterized x-ray and gamma ray beams at the National Research Council of Canada, air kerma measurements were used to compare a variety of commercial and pre-commercial radiation shielding materials over mean energy ranges from 39 to 205 keV. The EGSnrc Monte Carlo user code cavity.cpp was extended to provide computed spectra for a variety of elements that have been used as a replacement for Pb in radiation shielding garments. Computed air kerma values were compared with experimental values and with the SRS-30 catalogue of diagnostic spectra available through the Institute of Physics and Engineering in Medicine Report 78. In addition to garment materials, measurements also included pure Pb sheets, allowing direct comparisons to the common industry standards of 0.25 and 0.5 mm 'lead equivalent'. The parameter 'lead equivalent' is misleading, since photon attenuation properties for all materials (including Pb) vary significantly over the energy spectrum, with the largest variations occurring in the diagnostic imaging range. Furthermore, air kerma measurements are typically made to determine attenuation properties without reference to the measures of biological damage such as ambient dose equivalent, which also vary significantly with air kerma over the diagnostic imaging energy range. A single material or combination cannot provide optimum shielding for all energy ranges. However, appropriate choice of materials for a particular energy range can offer significantly improved shielding per unit mass over traditional Pb-based materials.

McCaffrey, J. P.; Shen, H.; Downton, B.; Mainegra-Hing, E. [Ionizing Radiation Standards, National Research Council of Canada, Ottawa, Ontario K1A 0R6 (Canada)

2007-02-15T23:59:59.000Z

83

The Physics Analysis of a Gas Attenuator with Argon as a Working Gas  

SciTech Connect

A gas attenuator is an important element of the LCLS facility. The attenuator must operate in a broad range of x-ray energies, provide attenuation coefficient between 1 and 10{sup 4} with the accuracy of 1% and, at the same time, be reliable and allow for many months of un-interrupted operation. S. Shen has recently carried out a detailed design study of the attenuator based on the use of nitrogen as a working gas. In this note we assess the features of the attenuator based on the use of argon. We concentrate on the physics issues, not the design features.

Ryutov,, D.D.

2010-12-07T23:59:59.000Z

84

CONSTRAINTS ON NEUTRON STAR MASS AND RADIUS IN GS 1826-24 FROM SUB-EDDINGTON X-RAY BURSTS  

SciTech Connect

We investigate the constraints on neutron star mass and radius in GS 1826-24 from models of light curves and spectral evolution of type I X-ray bursts. This source shows remarkable agreement with theoretical calculations of burst energies, recurrence times, and light curves. We first exploit this agreement to set the overall luminosity scale of the observed bursts. When combined with a measured blackbody normalization, this leads to a distance- and anisotropy-independent measurement of the ratio between the redshift 1 + z and color-correction factor f{sub c}. We find 1 + z = 1.19-1.28 for f{sub c} = 1.4-1.5. We then compare the evolution of the blackbody normalization with flux in the cooling tail of bursts with predictions from spectral models of Suleimanov et al. The observations are well described by the models at luminosities greater than about one-third of the peak luminosity, with deviations emerging at luminosities below that. We show that this comparison leads to distance-independent upper limits on R{sub {infinity}} and neutron star mass of R{sub {infinity}} {approx}< 9.0-13.2 km and M < 1.2-1.7 M{sub Sun }, respectively, for solar abundance of hydrogen at the photosphere and a range of metallicity and surface gravity. The radius limits are low in comparison to previous measurements. This may be indicative of a subsolar hydrogen fraction in the GS 1826-24 photosphere, or of larger color corrections than that predicted by spectral models. Our analysis also gives an upper limit on the distance to GS 1826-24 of d < 4.0-5.5 kpc {xi}{sup -1/2}{sub b}, where {xi}{sub b} is the degree of anisotropy of the burst emission.

Zamfir, Michael; Cumming, Andrew [Department of Physics, McGill University, 3600 rue University, Montreal, QC H3A 2T8 (Canada); Galloway, Duncan K., E-mail: mzamfir@physics.mcgill.ca, E-mail: cumming@physics.mcgill.ca, E-mail: Duncan.Galloway@monash.edu [Monash Centre for Astrophysics (MoCA), School of Physics, and School of Mathematical Sciences, Monash University, VIC 3800 (Australia)

2012-04-10T23:59:59.000Z

85

The Magneto Hydro Dynamical Model of KHz Quasi Periodic Oscillations in Neutron Star Low Mass X-ray Binaries (II)  

E-Print Network (OSTI)

We study the kilohertz quasi-periodic oscillations (kHz QPOs) in neutron star low mass X-ray binaries (LMXBs) with a new magnetohydrodynamics (MHD) model, in which the compressed magnetosphere is considered. The previous MHD model (Shi \\& Li 2009) is re-examined and the relation between the frequencies of the kHz QPOs and the accretion rate in LMXBs is obtained. Our result agrees with the observations of six sources (4U 0614+09, 4U 1636--53, 4U 1608--52, 4U 1915--15, 4U 1728--34, XTE 1807--294) with measured spins. In this model the kHz QPOs originate from the MHD waves in the compressed magnetosphere. The single kHz QPOs and twin kHz QPOs are produced in two different parts of the accretion disk and the boundary is close to the corotation radius. The lower QPO frequency in a frequency-accretion rate diagram is cut off at low accretion rate and the twin kHz QPOs encounter a top ceiling at high accretion rate due to the restriction of innermost stable circular orbit.

Shi, Chang-Sheng; Li, Xiang-Dong

2014-01-01T23:59:59.000Z

86

The Magnetohydrodynamical Model of Kilohertz Quasi-periodic Oscillations in Neutron Star Low-mass X-Ray Binaries (II)  

Science Journals Connector (OSTI)

We study the kilohertz quasi-periodic oscillations (kHz QPOs) in neutron star low-mass X-ray binaries (LMXBs) with a new magnetohydrodynamics (MHD) model, in which the compressed magnetosphere is considered. The previous MHD model is reexamined and the relation between the frequencies of the kHz QPOs and the accretion rate in LMXBs is obtained. Our result agrees with the observations of six sources (4U 0614+09, 4U 1636-53, 4U 1608-52, 4U 1915-15, 4U 1728-34, and XTE 1807-294) with measured spins. In this model, the kHz QPOs originate from the MHD waves in the compressed magnetosphere. The single kHz QPOs and twin kHz QPOs are produced in two different parts of the accretion disk and the boundary is close to the corotation radius. The lower QPO frequency in a frequency-accretion rate diagram is cut off at a low accretion rate and the twin kHz QPOs encounter a top ceiling at a high accretion rate due to the restriction of the innermost stable circular orbit.

Chang-Sheng Shi; Shuang-Nan Zhang; Xiang-Dong Li

2014-01-01T23:59:59.000Z

87

Some Constraints On the Effects of Age and Metallicity on the Low Mass X-ray Binary Formation Rate  

E-Print Network (OSTI)

We have studied the low mass X-ray binary (LMXB) populations within and outside globular clusters (GC) in NGC 4365 and NGC 3115. Using published age and metallicity constraints from optical and IR observations of their GCs, we do not find any evidence for an increase in the LMXB formation rate in the intermediate age cluster population of NGC 4365, as has been proposed in some scenarios of dynamical LMXB formation in GCs. The old, metal-rich, red population of GCs in NGC 3115 on the other hand is {\\it at least} three times as efficient at creating LMXBs as the old, metal-poor, blue clusters. These data suggest that the higher formation efficiency of LMXBs in the red GC subsystems of many galaxies is largely a consequence of their higher metallicity. A comparison of the densities of field LMXBs in different galaxies does not reveal an obvious correlation with the age of the field stars as predicted by models in which the LMXB formation rate in the field drops monotonically with time after an initial burst. This suggests that either a significant fraction of the field LMXBs are created in GCs and subsequently injected into the field, or the LMXB formation rate has a more complex time evolution pattern.

Arunav Kundu; Thomas J. Maccarone; Stephen E. Zepf; Thomas H. Puzia

2003-04-24T23:59:59.000Z

88

Broadband spectroscopy of the eclipsing high mass X-ray binary 4U 1700-37 with Suzaku  

E-Print Network (OSTI)

We present the results obtained from broadband spectroscopy of the high mass X-ray binary 4U 1700-37 using data from a Suzaku observation in 2006 September 13-14 covering 0.29-0.72 orbital phase range. The light curves showed significant and rapid variation in source flux during entire observation. We did not find any signature of pulsations in the light curves. However, a quasi-periodic oscillation at ~20 mHz was detected in the power density spectrum of the source. The 1-70 keV spectrum was fitted with various continuum models. However, we found that the partially absorbed high energy cutoff power-law and Negative and Positive power-law with Exponential cutoff (NPEX) models described the source spectrum well. Iron emission lines at 6.4 keV and 7.1 keV were detected in the source spectrum. An absorption like feature at ~39 keV was detected in the residuals while fitting the data with NPEX model. Considering the feature as cyclotron absorption line, the surface magnetic field of the neutron star was estimated...

Jaisawal, Gaurava K

2015-01-01T23:59:59.000Z

89

Measurements of the hard-x-ray reflectivity of iridium  

SciTech Connect

In connection with the design of a hard-x-ray telescope for the Constellation X-Ray Observatory we measured the reflectivity of an iridium-coated zerodur substrate as a function of angle at 55, 60, 70, and 80 keV at the National Synchrotron Light Source of Brookhaven National Laboratory. The optical constants were derived from the reflectivity data. The real component of the index of refraction is in excellent agreement with theoretical values at all four energies. However, the imaginary component, which is related to the mass attenuation coefficient, is 50% to 70% larger at 55, 60, and 70 keV than theoretical values.

Romaine, S.; Bruni, R.; Gorenstein, P.; Zhong, Z

2007-01-10T23:59:59.000Z

90

kHz Quasiperiodic Oscillations in Low-Mass X-Ray Binaries as Probes of General Relativity in the Strong-Field Regime  

Science Journals Connector (OSTI)

We consider the interpretation of a pair of kHz quasiperiodic oscillations (QPOs) in the Fourier spectra of two low-mass x-ray binaries, Sco X-1 and 4U1608-52, hosting an old accreting neutron star. The observed frequency difference of these QPOs decreases as their frequency increases, contrary to simple beat frequency models. We show that the behavior of these QPOs is instead well matched in terms of the fundamental frequencies for test particle motion in the gravitational field of the neutron star, for reasonable star masses, and nearly independent of the star spin. These results are not reproduced through the post–Newtonian approximation of general relativity. kHz QPOs from x-ray binaries likely provide an accurate laboratory for strong-field general relativity.

Luigi Stella and Mario Vietri

1999-01-04T23:59:59.000Z

91

The Gas Attenuator of FLASH at DESY  

SciTech Connect

FLASH (Free electron LASer at Hamburg) as a part of the Deutsches Elektronen Synchroton DESY is the first Free Electron Laser (FEL) user facility for VUV and soft X-ray coherent light experiments. The SASE (Self Amplification by Stimulated Emission) process generates ultra short coherent radiation pulses on the femtosecond time scale with peak powers in the GW range. Several experiments need reliable means to reduce the FEL intensity over many orders of magnitude without changing the photon beam characteristics. Since a reduction of the FEL intensity by variation of machine parameters is not appropriate, a windowless gas-filled cell in combination with differential pumping units is used for attenuating the FEL radiation. This attenuator is placed in the beamline in outside the experimental hall. The total length of the gas cell is 15 m and the maximum gas pressure, which can be handled by the differential pumping units, is about 0.1 mbar. The attenuation range of Nitrogen covers at least 5 orders of magnitude in the spectral range of 19 to 120 nm due to its large absorption cross section. Between 19 and 9 nm and for shorter wavelengths Xenon and Krypton can be used, respectively.

Hahn, Ulrich; Tiedtke, Kai [Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, 22603 Hamburg (Germany)

2007-01-19T23:59:59.000Z

92

Quasi Periodic Oscillations in Low Mass X-Ray Binaries and Constraints on the Equation of State of Neutron Star Matter  

E-Print Network (OSTI)

Recently discovered quasi periodic oscillations in the X-ray brightness of low mass X-ray binaries are used to derive constraints on the mass of the neutron star component and the equation of state of neutron star matter. The observations are compared with models of rapidly rotating neutron stars which are calculated by means of an exact numerical method in full relativity. For the equations of state we select a broad collection of models representing different assumptions about the many-body structure and the complexity of the composition of super dense matter. The mass constraints differ from their values in the approximate treatment by \\sim 10%. Under the assumption that the maximum frequency of the quasi periodic oscillations originates from the innermost stable orbit the mass of the neutron star is in the range: $M\\sim 1.92-2.25 M_\\odot$. Especially the quasi periodic oscillation in the Atoll-source 4U 1820-30 is only consistent with equations of state which are rather stiff at high densities which is explainable, so far, only with pure nucleonic/leptonic composition. This interpretation contradicts the hypothesis that the protoneutron star formed in SN 1987A collapsed to a black hole, since this would demand a maximum neutron star mass below $1.6 M_\\odot$. The recently suggested identification of quasi periodic oscillations with frequencies around 10 Hz with the Lense-Thirring precession of the accretion disk is found to be inconsistent with the models studied in this work, unless it is assumed that the first overtone of the precession is observed.

Christoph Schaab; Manfred K. Weigel

1999-04-16T23:59:59.000Z

93

On the possibility to discriminate the mass of the primary cosmic ray using the muon arrival times from extensive air showers: Application for Pierre Auger Observatory  

SciTech Connect

In this paper we study the possibility to discriminate the mass of the primary cosmic ray by observing the muon arrival times in ground detectors. We analyzed extensive air showers (EAS) induced by proton and iron nuclei with the same energy 8 Multiplication-Sign 10{sup 17} eV simulated with CORSIKA, and analyzed the muon arrival times at ground measured by the infill array detectors of the Pierre Auger Observatory (PAO). From the arrival times of the core and of the muons the atmospheric depth of muon generation locus is evaluated. The results suggest a potential mass discrimination on the basis of muon arrival times and of the reconstructed atmospheric depth of muon production. An analysis of a larger set of CORSIKA simulations carried out for primary energies above 10{sup 18} eV is in progress.

Arsene, N.; Rebel, H.; Sima, O. [Institute of Space Science (ISS), Bucharest-Magurele, P.O. Box MG-23 (Romania) and Physics Department, University of Bucharest, Bucharest-Magurele (Romania); Karlsruhe Institute of Technology, Karlsruhe (Germany); Physics Department, University of Bucharest, Bucharest-Magurele (Romania)

2012-11-20T23:59:59.000Z

94

Study of photon attenuation coefficients of some multielement materials. [123-1250 keV  

SciTech Connect

Total photon mass attenuation of six multielement shielding materials (concrete, plaster of paris, quick lime, black cement, white cement, and silica) is measured in the 123- to 1,250-keV energy range. The experimental results are analyzed in terms of cross sections, effective atomic numbers, and electron densities. Considerable sensitivity of the total mass attenuation coefficients and effective atomic numbers to variations in oxygen content are found in these multielement materials.

Bhandal, G.S. (N.J.S.A. Government Coll., Punjab (India)); Singh, K. (Guru Nanak Dev Univ., Amritsar (India). Dept. of Physics)

1994-03-01T23:59:59.000Z

95

Long-Lasting X-Ray Emission from Type IIb Supernova 2011dh and Mass-Loss History of The Yellow Supergiant Progenitor  

E-Print Network (OSTI)

Type IIb Supernova (SN) 2011dh, with conclusive detection of an unprecedented Yellow Supergiant (YSG) progenitor, provides an excellent opportunity to deepen our understanding on the massive star evolution in the final centuries toward the SN explosion. In this paper, we report on detection and analyses of thermal X-ray emission from SN IIb 2011dh at ~500 days after the explosion on Chandra archival data, providing a solidly derived mass loss rate of an YSG progenitor for the first time. We find that the circumstellar media (CSM) should be dense, more than that expected from a Wolf-Rayet (WR) star by one order of magnitude. The emission is powered by a reverse shock penetrating into an outer envelope, fully consistent with the YSG progenitor but not with a WR progenitor. The density distribution at the outermost ejecta is much steeper than that expected from a compact WR star, and this finding must be taken into account in modeling the early UV/optical emission from SNe IIb. The derived mass loss rate is 3 x ...

Maeda, Keiichi; Bamba, Aya; Terada, Yukikatsu; Fukazawa, Yasushi

2014-01-01T23:59:59.000Z

96

X-ray transmissive debris shield  

DOE Patents (OSTI)

An X-ray debris shield for use in X-ray lithography that is comprised of an X-ray window having a layer of low density foam exhibits increased longevity without a substantial increase in exposure time. The low density foam layer serves to absorb the debris emitted from the X-ray source and attenuate the shock to the window so as to reduce the chance of breakage. Because the foam is low density, the X-rays are hardly attenuated by the foam and thus the exposure time is not substantially increased.

Spielman, R.B.

1996-05-21T23:59:59.000Z

97

X-ray transmissive debris shield  

DOE Patents (OSTI)

An X-ray debris shield for use in X-ray lithography that is comprised of an X-ray window having a layer of low density foam exhibits increased longevity without a substantial increase in exposure time. The low density foam layer serves to absorb the debris emitted from the X-ray source and attenuate the shock to the window so as to reduce the chance of breakage. Because the foam is low density, the X-rays are hardly attenuated by the foam and thus the exposure time is not substantially increased.

Spielman, Rick B. (Albuquerque, NM)

1996-01-01T23:59:59.000Z

98

MEASUREMENT OF THE RADIUS OF NEUTRON STARS WITH HIGH SIGNAL-TO-NOISE QUIESCENT LOW-MASS X-RAY BINARIES IN GLOBULAR CLUSTERS  

SciTech Connect

This paper presents the measurement of the neutron star (NS) radius using the thermal spectra from quiescent low-mass X-ray binaries (qLMXBs) inside globular clusters (GCs). Recent observations of NSs have presented evidence that cold ultra dense matter-present in the core of NSs-is best described by ''normal matter'' equations of state (EoSs). Such EoSs predict that the radii of NSs, R{sub NS}, are quasi-constant (within measurement errors, of {approx}10%) for astrophysically relevant masses (M{sub NS}>0.5 M{sub Sun }). The present work adopts this theoretical prediction as an assumption, and uses it to constrain a single R{sub NS} value from five qLMXB targets with available high signal-to-noise X-ray spectroscopic data. Employing a Markov chain Monte-Carlo approach, we produce the marginalized posterior distribution for R{sub NS}, constrained to be the same value for all five NSs in the sample. An effort was made to include all quantifiable sources of uncertainty into the uncertainty of the quoted radius measurement. These include the uncertainties in the distances to the GCs, the uncertainties due to the Galactic absorption in the direction of the GCs, and the possibility of a hard power-law spectral component for count excesses at high photon energy, which are observed in some qLMXBs in the Galactic plane. Using conservative assumptions, we found that the radius, common to the five qLMXBs and constant for a wide range of masses, lies in the low range of possible NS radii, R{sub NS}=9.1{sup +1.3}{sub -1.5} km (90%-confidence). Such a value is consistent with low-R{sub NS} equations of state. We compare this result with previous radius measurements of NSs from various analyses of different types of systems. In addition, we compare the spectral analyses of individual qLMXBs to previous works.

Guillot, Sebastien; Rutledge, Robert E. [Department of Physics, McGill University, 3600 rue University, Montreal, QC, H2X-3R4 (Canada); Servillat, Mathieu [Laboratoire AIM (CEA/DSM/IRFU/SAp, CNRS, Universite Paris Diderot), CEA Saclay, Bat. 709, F-91191 Gif-sur-Yvette (France); Webb, Natalie A., E-mail: guillots@physics.mcgill.ca, E-mail: rutledge@physics.mcgill.ca [Universite de Toulouse, UPS-OMP, IRAP, Toulouse (France)

2013-07-20T23:59:59.000Z

99

Nuclear attenuation of three-hadron systems in neutrino-induced reactions  

E-Print Network (OSTI)

For the first time, the nuclear attenuation of three hadron systems is studied in neutrino-induced reactions using the data obtained with SKAT bubble chamber. The strongest attenuation (R_3 ~ 0.6) is observed for a system carrying an overwhelming fraction of the current quark energy, as well as for a system with the smallest effective mass. An indication is obtained that the correlation effects in the nuclear attenuation play only a minor role. The experimental data are compared with predictions of the quark string fragmentation model.

N. M. Agababyan; L. Grigorian; N. Grigoryan; H. Gulkanyan; A. A. Ivanilov; Zh. Karamyan; V. A. Korotkov

2011-08-08T23:59:59.000Z

100

MEASUREMENTS OF CYCLOTRON FEATURES AND PULSE PERIODS IN THE HIGH-MASS X-RAY BINARIES 4U 1538–522 AND 4U 1907+09 WITH THE INTERNATIONAL GAMMA-RAY ASTROPHYSICS LABORATORY  

SciTech Connect

We present a spectral and timing analysis of International Gamma-Ray Astrophysics Laboratory (INTEGRAL) observations of two high-mass X-ray binaries, 4U 1538–522 and 4U 1907+09. Our timing measurements for 4U 1538–522 find the pulse period to have exhibited a spin-up trend until approximately 2009, after which there is evidence for a torque reversal, with the source beginning to spin down to the most recently measured period of 525.407 ± 0.001 s. The most recent INTEGRAL observations of 4U 1907+09 are not found to yield statistically significant pulse periods due to the significantly lower flux from the source compared with 4U 1538–522. A spectral model consisting of a power-law continuum with an exponential cutoff and modified by two cyclotron resonance scattering features is found to fit both sources well, with the cyclotron scattering features detected at ?22 and ?49 keV for 4U 1538–522 and at ?18 and ?36 keV for 4U 1907+09. The spectral parameters of 4U 1538–522 are generally not found to vary significantly with flux and there is little to no variation across the torque reversal. Examining our results in conjunction with previous work, we find no evidence for a correlation between cyclotron line energy and luminosity for 4U 1538–522. 4U 1907+09 shows evidence for a positive correlation between cyclotron line energy and luminosity, which would make it the fourth, and lowest luminosity, cyclotron line source to exhibit this relationship.

Hemphill, Paul B.; Rothschild, Richard E. [Center for Astrophysics and Space Sciences, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 920093-0424 (United States); Caballero, Isabel [CEA Saclay, DSM/IRFU/SAp-UMR AIM (7158) CNRS/CEA/Université Paris 7, Diderot, F-91191 Gif-sur-Yvette (France); Pottschmidt, Katja [Center for Space Science and Technology, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250 (United States); Kühnel, Matthias; Wilms, Jörn [Dr. Karl Remeis-Sternwarte and Erlangen Center for Astroparticle Physics, Sternwartstr. 7, D-96049 Bamberg (Germany); Fürst, Felix, E-mail: pbhemphill@physics.ucsd.edu [Cahill Center for Astronomy and Astrophysics, California Institute of Technology, MC 290-17, 1200 East California Boulevard, Pasadena, CA 91125 (United States)

2013-11-01T23:59:59.000Z

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101

Shock-Wave Attenuation and Energy-Dissipation Potential of Granular Materials  

E-Print Network (OSTI)

Shock-Wave Attenuation and Energy-Dissipation Potential of Granular Materials Mica Grujicic, B this approach, both compression shocks and decompression waves are treated as (stress, specific volume, particle velocity, mass-based internal energy density, temperature, and mass-based entropy density) propagating

Grujicic, Mica

102

A Method for energy estimation and mass composition determination of primary cosmic rays at Chacaltaya observation level based on atmospheric Cerenkov light technique  

E-Print Network (OSTI)

A new method for energy and mass composition estimation of primary cosmic ray radiation based on atmospheric Cerenkov light flux in extensive air showers (EAS) analysis is proposed. The Cerenkov light flux in EAS initiated by primary protons and iron nuclei is simulated with CORSIKA 5.62 code for Chacaltaya observation level (536 g/cm2) in the energy range 10 TeV - 10 PeV. An adequate model, approximation of lateral distribution of Cerenkov light in showers is obtained. Using the proposed model and solution of overdetermined system of nonlinear equations based on Gauss Newton method with autoregularization, two different array detector arrangements are compared. The detector response for the detector sets is simulated. The accuracies in energy and shower axis determination are studied and the corresponding selection criteria are proposed. An approximation with nonlinear fit is obtained and the energy dependence of the proposed model function parameters is studied. The approximation of model parameters as function of the primary energy is carried out. This permits, taking into account the properties of the proposed method and model, to distinguish proton primaries from iron primaries. The detector response for the detector sets is simulated and the accuracies in energy determination are calculated. Moreover the accuracies in shower axis determination are studied and criteria in shower axis position estimation are proposed.

S. Mavrodiev; A. Mishev; J. Stamenov

2003-10-22T23:59:59.000Z

103

Is pelvic bone mineral content assessed through dual energy X-ray absorptionmetry an appropriate anatomical area for bone mass estimation in women?  

Science Journals Connector (OSTI)

Bibliographic references seem very controversill regarding the most appropriate anatomical area for bone mass estimation. Since some overlapping in the different bone mass measurements among normal and osteopo...

Prof. Dr. H. Rico; M. Revilla; E. R. Hernández; L. F. Villa…

1992-12-01T23:59:59.000Z

104

Monitored Natural Attenuation of Chlorinated Solvents - Moving Beyond Reuctive Dechlorination  

SciTech Connect

Monitored natural attenuation (MNA), while a remedy of choice for many sites, can be challenging when the contaminants are chlorinated solvents. Even with many high quality technical guidance references available there continue to be challenges implementing MNA at some chlorinated solvent sites. The U.S. Department of Energy, as one organization facing such challenges, is leading a project that will incorporate developing concepts and tools into the existing toolbox for selecting and implementing MNA as a remediation option at sites with chlorinated solvents contamination. The structure and goals of this project were introduced in an article in the Winter 2004 issue of Remediation (Sink et al.). This article is a summary of the three technical areas being developed through the project: mass balance, enhanced attenuation, and characterization and monitoring supporting the first two areas. These topics will be documented in separate reports available from the US Department of Energy Office of Scientific and Technical Information at www.osti.gov.

Vangelas, K

2006-04-10T23:59:59.000Z

105

Enhancements to Natural Attenuation: Selected Case Studies |...  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Selected Case Studies More Documents & Publications Building C-400 Thermal Treatment 90% Remedial Design Report and Site Investigation Natural and Enhanced Attenuation of Soil and...

106

An analysis of phase change material as thermal mass  

Science Journals Connector (OSTI)

...1006 40 117 An analysis of phase change material as thermal mass M.J Richardson...attenuated by thermal mass. Adding phase change material (PCM) to thermal mass increases...with heavyweight structures. phase change material|thermal mass|energy storage...

2008-01-01T23:59:59.000Z

107

Attenuation of two-dimensional plasmons  

Science Journals Connector (OSTI)

We calculate the attenuation of gapless plasmons in single- and double-layer electron systems by including higher-order corrections to the electron polarization operator from the Coulomb interaction. Both particle-hole excitations and plasmons in the intermediate states contribute to the relaxation. The obtained results are in good agreement with experimental findings for temperatures above 30 K. We also make predictions for plasmon attenuation at low temperatures where no experimental data are currently available.

M. Yu. Reizer and V. M. Vinokur

2000-12-15T23:59:59.000Z

108

Far-infrared attenuation in glasses  

Science Journals Connector (OSTI)

The influence of quasilocal vibrations on the far-infrared spectra of glasses is investigated under the supposition that the quasilocal vibrations are directly inactive in the attenuation. It is shown that taking into account phonon-quasilocal-vibration coupling and both medium- and short-range structure of the inhomogeneities of a photon-phonon coupling parameter can give rise to an attenuation curve similar to one observed for a-SiO2 and related materials.

Lev I. Deich

1994-01-01T23:59:59.000Z

109

X-ray beam finder  

DOE Patents (OSTI)

An X-ray beam finder for locating a focal spot of an X-ray tube includes a mass of X-ray opaque material having first and second axially-aligned, parallel-opposed faces connected by a plurality of substantially identical parallel holes perpendicular to the faces and a film holder for holding X-ray sensitive film tightly against one face while the other face is placed in contact with the window of an X-ray head.

Gilbert, H.W.

1983-06-16T23:59:59.000Z

110

Changes in Bone Mineral, Lean Body Mass and Fat Content as Measured by Dual Energy X-ray Absorptiometry: A Longitudinal Study  

Science Journals Connector (OSTI)

Bone mineral density (BMD) and soft tissue composition were measured by dual energy X-ray absorptiometry (DXA) 3–4 years apart in 273 men and women aged 23–90. We found different rates of BMD loss in differen...

M. K. Karlsson; K. J. Obrant; B. E. Nilsson; O. Johnell

2000-02-01T23:59:59.000Z

111

Temperature Dependence of Microwave Phonon Attenuation  

Science Journals Connector (OSTI)

Measurements of the temperature dependence of the attenuation of 9-Gc/sec phonons are presented. They include measurements on crystals of quartz, CdS, GaAs, Ge, Si, CaF2, Al2O3, and MgO in several directions and modes of polarization. The attenuation in most of the materials is proportional to Tn, where the average value of n=4.1±1.2 for the fast transverse waves, 4.0±1.7 for the slow transverse waves, 4.8±1.4 for the longitudinal waves. For MgO and Al2O3 the attenuation is proportional to the frequency of the sound between 3 and 9 Gc/sec. An empirical correlation of the data is that the attenuation of 9-Gc/sec phonons is 3 dB/cm when (T?)?0.1, where ?=Debye temperature of the crystal . Values of the third-order elastic constants are used to make absolute comparisons of the theory of attenuation by three-phonon processes with the data. The agreement is good in some cases but not in others.

M. Pomerantz

1965-07-19T23:59:59.000Z

112

Entanglement sensitivity to signal attenuation and amplification  

E-Print Network (OSTI)

We analyze general laws of continuous-variable entanglement dynamics during the deterministic attenuation and amplification of the physical signal carrying the entanglement. These processes are inevitably accompanied by noises, so we find fundamental limitations on noise intensities that destroy entanglement of gaussian and non-gaussian input states. The phase-insensitive amplification $\\Phi_1 \\otimes \\Phi_2 \\otimes \\ldots \\Phi_N$ with the power gain $\\kappa_i \\ge 2$ ($\\approx 3$ dB, $i=1,\\ldots,N$) is shown to destroy entanglement of any $N$-mode gaussian state even in the case of quantum limited performance. In contrast, we demonstrate non-gaussian states with the energy of a few photons such that their entanglement survives within a wide range of noises beyond quantum limited performance for any degree of attenuation or gain. We detect entanglement preservation properties of the channel $\\Phi_1 \\otimes \\Phi_2$, where each mode is deterministically attenuated or amplified. Gaussian states of high energy are shown to be robust to very asymmetric attenuations, whereas non-gaussian states are at an advantage in the case of symmetric attenuation and general amplification. If $\\Phi_1 = \\Phi_2$, the total noise should not exceed $\\frac{1}{2} \\sqrt{\\kappa^2+1}$ to guarantee entanglement preservation.

Sergey N. Filippov; Mario Ziman

2014-07-03T23:59:59.000Z

113

Flicker attenuation and transfer study for induction generator integrated into distribution network  

Science Journals Connector (OSTI)

Abstract Squirrel-cage induction generators (IGs) are widely used in distributed generation (DG). When the voltage at the point of common coupling is fluctuant, the embedded IG will show the impedance characteristic with dynamic changes under the different fluctuation frequencies. In addition, the drive train of IG set has great impact on the voltage flicker attenuation. This paper observes the dynamic response of IG to the voltage flicker through the experiments and further defines the flicker attenuation factor and transfer coefficient. A linearization model of IG with two-mass equivalent drive train is constructed through comparing the impacts of different drive trains (such as diesel engine, wind turbine) on the voltage flicker attenuation. Then an analytical method is proposed to determine the dynamic impedance, attenuation factor, transfer coefficient and flicker limit for IG integrated into distribution network. The correctness of the proposed method is verified by the experimental tests and the dynamic simulation using the detailed model of IG set. The parameters sensitivities of drive train and generator to the voltage flicker attenuation effect are analyzed and discussed in the paper.

Qianggang Wang; Niancheng Zhou; Jizhong Zhu; Wei Yan; Shu Pan

2014-01-01T23:59:59.000Z

114

DETECTING AND QUANTIFYING REDUCTIVE DECHLORINATION DURING MONITORED NATURAL ATTENUATION AT THE SAVANNAH RIVER CBRP SITE  

SciTech Connect

Various attenuation mechanisms control the destruction, stabilization, and/or removal of contaminants from contaminated subsurface systems. Measuring the rates of the controlling attenuation mechanisms is a key to employing mass balance as a means to evaluate and monitor the expansion, stability and subsequent shrinkage of a contaminant plume. A team of researchers investigated the use of push-pull tests for measuring reductive dechlorination rates in situ at sites with low chlorinated solvent concentrations (<1 ppm). The field research also examined the synergistic use of a suite of geochemical and microbial assays. Previous push-pull tests applied to environmental remediation objectives focused on general hydrological characterization or on designing bioremediation systems by examining the response of the subsurface to stimulation. In this research, the push-pull technique was tested to determine its ''low-range'' sensitivity and uncertainty. Can these tests quantify relatively low attenuation rates representative of natural attenuation? The results of this research indicate that push-pull testing will be useful for measurement of in situ reductive dechlorination rates for chlorinated solvents at ''Monitored Natural Attenuation'' (MNA) sites. Further, using principal component analysis and other techniques, the research confirmed the usefulness of multiple lines of evidence in site characterization and in upscaling measurements made in individual wells--especially for sites where there is a geochemical gradient or varying geochemical regimes within the contaminant plume.

Vangelas, K; JACK D. ISTOK, J; JENNIFER A. FIELD, J; ERIC RAES, E; Margaret Millings, M; AARON D. PEACOCK, A; Brian02 Looney, B

2007-01-02T23:59:59.000Z

115

Attenuation of sound waves in drill strings  

Science Journals Connector (OSTI)

During drilling of deep wells digital data are often transmitted from sensors located near the drill bit to the surface. Development of a new communication system with increased data capacity is of paramount importance to the drilling industry. Since steel drill strings are used transmission of these data by elastic carrier waves traveling within the drill pipe is possible but the potential communication range is uncertain. The problem is complicated by the presence of heavy?threaded tool joints every 10 m which form a periodic structure and produce classical patterns of passbands and stop bands in the wave spectra. In this article field measurements of the attenuation characteristics of a drill string in the Long Valley Scientific Well in Mammoth Lakes California are presented. Wave propagation distances approach 2 km. A theoretical model is discussed which predicts the location width and attenuation of the passbands. Mode conversion between extensional and bending waves and spurious reflections due to deviations in the periodic spacings of the tool joints are believed to be the sources of this attenuation. It is estimated that attenuation levels can be dramatically reduced by rearranging the individual pipes in the drill string according to length.

Douglas S. Drumheller

1993-01-01T23:59:59.000Z

116

Systematic Uncertainties in the Spectroscopic Measurements of Neutron-Star Masses and Radii from Thermonuclear X-ray Bursts. III. Absolute Flux Calibration  

E-Print Network (OSTI)

Many techniques for measuring neutron star radii rely on absolute flux measurements in the X-rays. As a result, one of the fundamental uncertainties in these spectroscopic measurements arises from the absolute flux calibrations of the detectors being used. Using the stable X-ray burster, GS 1826-238, and its simultaneous observations by Chandra HETG/ACIS-S and RXTE/PCA as well as by XMM-Newton EPIC-pn and RXTE/PCA, we quantify the degree of uncertainty in the flux calibration by assessing the differences between the measured fluxes during bursts. We find that the RXTE/PCA and the Chandra gratings measurements agree with each other within their formal uncertainties, increasing our confidence in these flux measurements. In contrast, XMM-Newton EPIC-pn measures 14.0$\\pm$0.3% less flux than the RXTE/PCA. This is consistent with the previously reported discrepancy with the flux measurements of EPIC-pn, compared to EPIC-MOS1, MOS2 and ACIS-S detectors. We also address the calibration uncertainty in the RXTE/PCA int...

Guver, Tolga; Marshall, Herman; Psaltis, Dimitrios; Guainazzi, Matteo; Diaz-Trigo, Maria

2015-01-01T23:59:59.000Z

117

The measurement of attenuation from vertical seismic profiles  

E-Print Network (OSTI)

that attenuation is linear with frequency, the very assumption used to generate the synthetic VSP! To understand how this phenomena comes about, the data processing scheme used to generate the synthetic VSP cumulative attenuation values must be investigated... that attenuation is linear with frequency, the very assumption used to generate the synthetic VSP! To understand how this phenomena comes about, the data processing scheme used to generate the synthetic VSP cumulative attenuation values must be investigated...

Davis, Francis Erwin

2012-06-07T23:59:59.000Z

118

FREQUENCY DEPENDENT ULTRASONIC ATTENUATION COEFFICIENT ASSESSMENT IN FRESH  

E-Print Network (OSTI)

dependency of the ultrasonic attenuation coefficient ranges from f * e to fl.3 6 and its magnitude at 1 MHz dependent attenuation coefficient must be described by a higher ordered function than a simple power fit at the Bioacoustics Research Laboratory (2). A system block diagram appears in Figure 1. CHART ATTENUATOR ALU Ml

Illinois at Urbana-Champaign, University of

119

Applied Field Research Initiative Attenuation Based Remedies  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

PA00133 - March 2011 PA00133 - March 2011 Applied Field Research Initiative Attenuation Based Remedies in the Subsurface Located at the Savannah River Site in Aiken, South Carolina, the Attenuation-Based Remedies in the Subsurface Applied Field Research Initiative (ABRS AFRI) was established to develop the tools, approaches and technologies that will be required to address the technical challenges associated characteriza- tion, remediation and long-term monitoring of recalcitrant compounds in the subsurface at Department of Energy (DOE) Environmental Management (EM) sites. The ABRS AFRI site provides a unique setting for researchers in both applied and basic science fields. A wealth of subsurface data is available to support research activities and remedial decision making.

120

Exact Reconstruction From Uniformly Attenuated Helical Cone-Beam Projections in SPECT  

SciTech Connect

In recent years the development of cone-beam reconstruction algorithms has been an active research area in x-ray computed tomography (CT), and significant progress has been made in the advancement of algorithms. Theoretically exact and computationally efficient analytical algorithms can be found in the literature. However, in single photon emission computed tomography (SPECT), published cone-beam reconstruction algorithms are either approximate or involve iterative methods. The SPECT reconstruction problem is more complicated due to degradations in the imaging detection process, one of which is the effect of attenuation of gamma ray photons. Attenuation should be compensated for to obtain quantitative results. In this paper, an analytical reconstruction algorithm for uniformly attenuated cone-beam projection data is presented for SPECT imaging. The algorithm adopts the DBH method, a procedure consisting of differentiation and backprojection followed by a finite inverse cosh-weighted Hilbert transform. The significance of the proposed approach is that a selected region of interest can be reconstructed even with a detector with a reduced field of view. The algorithm is designed for a general trajectory. However, to validate the algorithm, a numerical study was performed using a helical trajectory. The implementation is efficient and the simulation result is promising.

Gullberg, Grant T; Huang, Qiu; You, Jiangsheng; Zeng, Gengsheng L.

2008-12-18T23:59:59.000Z

Note: This page contains sample records for the topic "ray mass attenuation" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
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We encourage you to perform a real-time search of NLEBeta
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121

Seismic Attenuation Inversion with t* Using tstarTomog.  

SciTech Connect

Seismic attenuation is defined as the loss of the seismic wave amplitude as the wave propagates excluding losses strictly due to geometric spreading. Information gleaned from seismic waves can be utilized to solve for the attenuation properties of the earth. One method of solving for earth attenuation properties is called t*. This report will start by introducing the basic theory behind t* and delve into inverse theory as it pertains to how the algorithm called tstarTomog inverts for attenuation properties using t* observations. This report also describes how to use the tstarTomog package to go from observed data to a 3-D model of attenuation structure in the earth.

Preston, Leiph

2014-09-01T23:59:59.000Z

122

High power radio frequency attenuation device  

DOE Patents (OSTI)

A resistor device for attenuating radio frequency power includes a radio frequency conductor connected to a series of fins formed of high relative magnetic permeability material. The fins are dimensional to accommodate the skin depth of the current conduction therethrough, as well as an inner heat conducting portion where current does not travel. Thermal connections for air or water cooling are provided for the inner heat conducting portions of each fin. Also disclosed is a resistor device to selectively alternate unwanted radio frequency energy in a resonant cavity.

Kerns, Quentin A. (Bloomingdale, IL); Miller, Harold W. (Winfield, IL)

1984-01-01T23:59:59.000Z

123

E-Print Network 3.0 - airborne lead x-ray Sample Search Results  

NLE Websites -- All DOE Office Websites (Extended Search)

Pulsars... you'd . . . Active Galactic . . . X-ray binaries Pulsars and relatives Gamma-ray bursts Gravitational... 1 - Type 2 X-ray binaries - Low mass X-ray binaries (LMXBs)...

124

Ultrasound Attenuation of Superfluid He3 in Aerogel  

Science Journals Connector (OSTI)

We have performed longitudinal ultrasound (9.5 MHz) attenuation measurements in the B phase of superfluid He3 in 98% porosity aerogel down to the zero temperature limit for a wide range of pressures at zero magnetic field. The absolute attenuation was determined by direct transmission of sound pulses. Compared to the bulk fluid, our results revealed a drastically different behavior in attenuation, which is consistent with theoretical accounts with gapless excitations and a collision drag effect.

H. C. Choi; N. Masuhara; B. H. Moon; P. Bhupathi; M. W. Meisel; Y. Lee; N. Mulders; S. Higashitani; M. Miura; K. Nagai

2007-06-01T23:59:59.000Z

125

Vinpocetine attenuates lipid accumulation and atherosclerosis formation  

SciTech Connect

Highlights: •Vinpocetine attenuates hyperlipidemia-induced atherosclerosis in a mouse model. •Vinpocetine antagonizes ox-LDL uptake and accumulation in macrophages. •Vinpocetine blocks the induction of ox-LDL receptor LOX-1 in vitro and in vivo. -- Abstract: Atherosclerosis, the major cause of myocardial infarction and stroke, is a chronic arterial disease characterized by lipid deposition and inflammation in the vessel wall. Cholesterol, in low-density lipoprotein (LDL), plays a critical role in the pathogenesis of atherosclerosis. Vinpocetine, a derivative of the alkaloid vincamine, has long been used as a cerebral blood flow enhancer for treating cognitive impairment. Recent study indicated that vinpocetine is a potent anti-inflammatory agent. However, its role in the pathogenesis of atherosclerosis remains unexplored. In the present study, we show that vinpocetine significantly reduced atherosclerotic lesion formation in ApoE knockout mice fed with a high-fat diet. In cultured murine macrophage RAW264.7 cells, vinpocetine markedly attenuated oxidized LDL (ox-LDL) uptake and foam cell formation. Moreover, vinpocetine greatly blocked the induction of ox-LDL receptor 1 (LOX-1) in cultured macrophages as well as in the LOX-1 level in atherosclerotic lesions. Taken together, our data reveal a novel role of vinpocetine in reduction of pathogenesis of atherosclerosis, at least partially through suppressing LOX-1 signaling pathway. Given the excellent safety profile of vinpocetine, this study suggests vinpocetine may be a therapeutic candidate for treating atherosclerosis.

Cai, Yujun [Aab Cardiovascular Research Institute, Department of Medicine, University of Rochester, 601 Elmwood Ave, Rochester, NY 14642 (United States)] [Aab Cardiovascular Research Institute, Department of Medicine, University of Rochester, 601 Elmwood Ave, Rochester, NY 14642 (United States); Li, Jian-Dong [Center for Inflammation, Immunity and Infection, and Department of Biology, Georgia State University, Atlanta, GA 30303 (United States)] [Center for Inflammation, Immunity and Infection, and Department of Biology, Georgia State University, Atlanta, GA 30303 (United States); Yan, Chen, E-mail: Chen_Yan@urmc.rochester.edu [Aab Cardiovascular Research Institute, Department of Medicine, University of Rochester, 601 Elmwood Ave, Rochester, NY 14642 (United States)] [Aab Cardiovascular Research Institute, Department of Medicine, University of Rochester, 601 Elmwood Ave, Rochester, NY 14642 (United States)

2013-05-10T23:59:59.000Z

126

Coherence length of cosmic background radiation enlarges the attenuation length of the ultra-high energy proton  

E-Print Network (OSTI)

It is pointed out that an agreement of the one particle energy spectrum of the cosmic background radiation (CMBR) with Plank distribution of 2.725 [K] does not give a strong constraint on the coherence length of CMBR if the mean free path of CMBR is very long. The coherence length in this situation is estimated as a few times of $k_BT$. Due to this finite coherence length, the attenuation length of ultra-high energy cosmic rays (UHECR) is reduced in the $\\Delta $ resonance region,i.e., around $10^{20}$ [eV]. The small attenuation length makes the suppression of the flux of cosmic rays in this energy region less prominent than the naive estimation

Kenzo Ishikawa; Yutaka Tobita

2008-01-21T23:59:59.000Z

127

SU?E?I?41: Study On the CT Radiation Attenuation Characteristics of Human Body for Phantom Design Using Monte Carlo Simulations  

Science Journals Connector (OSTI)

Purpose: The CTDI values measured with standard PMMA phantoms were now being challenged due to the clinical application of new technologies such as automatic tube current modulation(TCM) the aim of this study is to simulate the CT radiation attenuation characteristics of human body along Z?axis which were the basic data of developing new phantoms used to evaluate TCM. Methods: The CT model used in this study has been modeled including the source energy spectrum the bow?tie filter as well and the beam shape. The voxel phantoms RPI Adult Male designed to match the ICRP anatomical references for average individuals were also selected in this study. MCNPX 2.5.0 was used to simulate the 120 kVp CT X?ray attenuation of voxel phantom along the z?axis. Averaged photon flux was tallied before and after it passed though the phantom separately simulations were also carried out using different thickness of PMMA plates instead of the voxel phantom. Results: The CT X?ray attenuation of PMMA and its thickness presents a significant negative exponential relationship with the r2=0.9975. The CT X?ray attenuation data of every 2cm along Z?axis direction of voxel phantom were obtained combined with characteristics of CT X?ray attenuation of PMMA the PMMA equivalent thickness of the voxel phantom torso along the Z?axis direction in terms of CT X?ray attenuation were calculated. The PMMA equivalent thickness ranges from 5.5cm to 30.1cm. The liver and spleen plane which contents substantive organs such as the liver and spleen and bone structure as ribs and the lumbar was the maximum attenuation plane. Conclusion: The trend of the overall attenuation characteristics of the human body in terms of CT X?ray was in accord with the anatomical structure these results could be used to develop new dose phantoms which were used to evaluate automatic tube current modulation with further study. This project was partially funded by National Institutes of Health (National Library of Medicine R01LM009362 and National Institute of Biomedical Imaging and Bioengineering R42EB010404)

h Liu

2013-01-01T23:59:59.000Z

128

Turbulence attenuation by large neutrally buoyant particles  

E-Print Network (OSTI)

Turbulence modulation by inertial-range-size, neutrally-buoyant particles is investigated experimentally in a von K\\'arm\\'an flow. Increasing the particle volume fraction $\\Phi_\\mathrm{v}$, maintaining constant impellers Reynolds number attenuates the fluid turbulence. The inertial-range energy transfer rate decreases as $\\propto\\Phi_\\mathrm{v}^{2/3}$, suggesting that only particles located on a surface affect the flow. Small-scale turbulent properties, such as structure functions or acceleration distribution, are unchanged. Finally, measurements hint at the existence of a transition between two different regimes occurring when the average distance between large particles is of the order of the thickness of their boundary layers.

Cisse, Mamadou; Gibert, Mathieu; Bodenschatz, Eberhard; Bec, Jeremie

2015-01-01T23:59:59.000Z

129

NEBULAR ATTENUATION IN H{alpha}-SELECTED STAR-FORMING GALAXIES AT z = 0.8 FROM THE NewH{alpha} SURVEY  

SciTech Connect

We present measurements of the dust attenuation of H{alpha}-selected emission-line galaxies at z = 0.8 from the NewH{alpha} narrowband survey. The analysis is based on deep follow-up spectroscopy with Magellan/IMACS, which captures the strong rest-frame optical emission lines from [O II] {lambda}3727 to [O III] {lambda}5007. The spectroscopic sample used in this analysis consists of 341 confirmed H{alpha} emitters. We place constraints on the active galactic nucleus (AGN) fraction using diagnostics that can be applied at intermediate redshift. We find that at least 5% of the objects in our spectroscopic sample can be classified as AGNs and 2% are composite, i.e., powered by a combination of star formation and AGN activity. We measure the dust attenuation for individual objects from the ratios of the higher order Balmer lines. The H{beta} and H{gamma} pair of lines is detected with S/N > 5 in 55 individual objects and the H{beta} and H{delta} pair is detected in 50 individual objects. We also create stacked spectra to probe the attenuation in objects without individual detections. The median attenuation at H{alpha} based on the objects with individually detected lines is A(H{alpha}) = 0.9 {+-} 1.0 mag, in good agreement with the attenuation found in local samples of star-forming galaxies. We find that the z = 0.8 galaxies occupy a similar locus of attenuation as a function of magnitude, mass, and star formation rate (SFR) as a comparison sample drawn from the SDSS DR4. Both the results from the individual z = 0.8 galaxies and from the stacked spectra show consistency with the mass-attenuation and SFR-attenuation relations found in the local universe, indicating that these relations are also applicable at intermediate redshift.

Momcheva, Ivelina G. [Astronomy Department, Yale University, New Haven, CT 06511 (United States); Lee, Janice C.; Ouchi, Masami [Carnegie Observatories, Pasadena, CA 91101 (United States); Ly, Chun [Space Telescope Science Institute, Baltimore, MD 21218 (United States); Salim, Samir [Astronomy Department, Indiana University, Bloomington, IN 47405 (United States); Dale, Daniel A. [Department of Physics and Astronomy, University of Wyoming, Laramie, WY 82071 (United States); Finn, Rose [Physics Department, Siena College, Loudonville, NY 12211 (United States); Ono, Yoshiaki, E-mail: ivelina.momcheva@yale.edu [Department of Astronomy, Graduate School of Science, University of Tokyo, Bunkyo-ku, Tokyo 113-0033 (Japan)

2013-02-01T23:59:59.000Z

130

Kirchhoff modeling for attenuative anisotropic media using Gaussian beams  

E-Print Network (OSTI)

Kirchhoff modeling for attenuative anisotropic media using Gaussian beams Bharath Shekar1 and Ilya the Kirchhoff scattering integral and summation of Gaussian beams. The Green's functions are computed in the reference elastic model by Gaussian-beam summation, and the influence of attenuation is incorporated

Tsvankin, Ilya

131

Low?Frequency Acoustic Attenuation in the South Pacific Ocean  

Science Journals Connector (OSTI)

The first known measurement of the attenuation of sound in deep water at frequencies below 1 kHz in the South Pacific Ocean is described. The receiver was situated off the east coast of the North Island of New Zealand. It was found that the attenuations are in most cases comparable with the values of attenuation measured in the North Pacific Ocean and the Atlantic Ocean between Bermuda and South America. However on one of the paths over which the attenuation was measured there was an abrupt change in the quality of sound transmission which is thought to be a result of the path crossing the Subtropical Convergence; south of this discontinuity the attenuations were found to be comparable with those obtained previously in the Southern Ocean.

A. C. Kibblewhite; R. N. Denham

1971-01-01T23:59:59.000Z

132

High energy cosmic rays, gamma rays and neutrinos from AGN  

E-Print Network (OSTI)

The author reviews a model for the emission of high energy cosmic rays, gamma-rays and neutrinos from AGN (Active Galactic Nuclei) that he has proposed since 1985. Further discussion of the knee energy phenomenon of the cosmic ray energy spectrum requires the existence of a heavy particle with mass in the knee energy range. A possible method of detecting such a particle in the Pierre Auger Project is suggested. Also presented is a relation between the spectra of neutrinos and gamma-rays emitted from AGN. This relation can be tested by high energy neutrino detectors such as ICECUBE, the Mediterranean Sea Detector and possibly by the Pierre Auger Project.

Yukio Tomozawa

2008-02-03T23:59:59.000Z

133

X-ray Observations of Mrk 231  

E-Print Network (OSTI)

This paper presents new X-ray observations of Mrk 231, an active galaxy of particular interest due to its large infrared luminosity and the presence of several blueshifted broad absorption line (BAL) systems, a phenomenon observed in a small fraction of QSOs. A ROSAT HRI image of Mrk 231 is presented, this shows an extended region of soft X-ray emission, covering several tens of kpc, consistent with the extent of the host galaxy. An ASCA observation of Mrk 231 is also presented. Hard X-rays are detected but the data show no significant variability in X-ray flux. The hard X-ray continuum is heavily attenuated and X-ray column estimates range from ~ 2 x 10^{22} - 10^{23} cm^{-2} depending on whether the material is assumed to be neutral or ionized, and on the model assumed for the extended X-ray component. These ASCA data provide only the second hard X-ray spectrum of a BAL AGN presented to date. The broad-band spectral-energy-distribution of the source is discussed. While Mrk 231 is X-ray weak compared to Seyfert 1 galaxies, it has an optical-to-X-ray spectrum typical of a QSO.

T. J. Turner

1998-08-10T23:59:59.000Z

134

E-Print Network 3.0 - attenuates bone cancer-induced Sample Search...  

NLE Websites -- All DOE Office Websites (Extended Search)

is incorrectly classified as bone when forming the linear attenuation coefficient image. We then investigate two... of attenuation coefficients of water (represent- ing...

135

E-Print Network 3.0 - anp attenuates inflammatory Sample Search...  

NLE Websites -- All DOE Office Websites (Extended Search)

Regulation Summary: frequency and in the high frequency domain with incremental ANP infusion. Propranolol attenuated ANP induced... was not attenuated with HALauthormanuscriptins...

136

E-Print Network 3.0 - attenuation parameter studies Sample Search...  

NLE Websites -- All DOE Office Websites (Extended Search)

using the Summary: and Coudin, 1992). Intrinsic attenuation transfers wave energy to heat. In this study, we concentrate... and attenuation: J. Geophys. Res., 84, 4137-4748....

137

E-Print Network 3.0 - attenuation processes applying Sample Search...  

NLE Websites -- All DOE Office Websites (Extended Search)

correction when radial... correction is applied. Such cases serve as baselines for comparison. Attenuated radar data are assimilated... from using attenuated reflectivity data...

138

E-Print Network 3.0 - attenuator wave energy Sample Search Results  

NLE Websites -- All DOE Office Websites (Extended Search)

in estuaries Summary: is the effectiveness of saltmarsh vegetation in attenuating the energy of both wind and tidal waves and the ensuing... Modelling wave attenuation over the...

139

Microsoft Word - S05418_NatEnhAttenuation.doc  

Office of Legacy Management (LM)

Natural and Enhanced Attenuation Natural and Enhanced Attenuation of Soil and Groundwater at the Monument Valley, Arizona, DOE Legacy Waste Site 2008 Pilot Study Status Report August 2009 LMS/MON/S05418 This page intentionally left blank LMS/MON/S05418 Natural and Enhanced Attenuation of Soil and Groundwater at the Monument Valley, Arizona, DOE Legacy Waste Site 2008 Pilot Study Status Report August 2009 This page intentionally left blank U.S. Department of Energy 2008 Pilot Study Status Report August 2009 Doc. No. S05418 Page iii Contents Abbreviations.......................................................................................................................... vii Executive Summary.................................................................................................................

140

Lifetime measurements by the Doppler-shift attenuation method in the {sup 115}Sn({alpha},n{gamma}){sup 118}Te reaction  

SciTech Connect

{gamma} rays were measured at several angles in both singles and coincidence modes in the {sup 115}Sn({alpha},n{gamma}){sup 118}Te reaction at 15 MeV on a thick target. Multipolarities and mixing ratios were determined from the {gamma}-ray angular distribution analysis. Lifetimes of 11 low- and medium-spin excited states in {sup 118}Te were determined from a Monte Carlo Doppler-shift attenuation method analysis of the Doppler broadened line shapes of {gamma} rays deexciting the levels. The results are discussed in comparison with the predictions of the interacting boson model.

Mihai, C. [Horia Hulubei National Institute of Physics and Nuclear Engineering, RO-077125 Bucharest (Romania); Faculty of Physics, University of Bucharest, Bucharest (Romania); Pasternak, A. A. [Cyclotron Laboratory, A.F. Ioffe Physical Technical Institute, 194021 St. Petersburg (Russian Federation); Pascu, S.; Filipescu, D.; Ivascu, M.; Bucurescu, D.; Cata-Danil, I.; Deleanu, D.; Ghita, D. G.; Glodariu, T.; Marginean, N.; Marginean, R.; Negret, A.; Sava, T.; Stroe, L.; Suliman, G.; Zamfir, N. V. [Horia Hulubei National Institute of Physics and Nuclear Engineering, RO-077125 Bucharest (Romania); Cata-Danil, G. [Horia Hulubei National Institute of Physics and Nuclear Engineering, RO-077125 Bucharest (Romania); Physics Department, University 'Politehnica' of Bucharest, Bucharest (Romania)

2011-05-15T23:59:59.000Z

Note: This page contains sample records for the topic "ray mass attenuation" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


141

Ultrasonic attenuation imaging in a rodent thyroid cancer model  

E-Print Network (OSTI)

, a Kruskal-Wallis test was conducted to analyze if statistically significant differences in the mean AC slope of attenuation in thyroid tissues. The Kruskal- Wallis test reported statistically significant differences

Illinois at Urbana-Champaign, University of

142

Anomalous shear wave attenuation in the shallow crust beneath...  

Open Energy Info (EERE)

10 km volume of the shallow crust (one shallower than 5 km) that severely attenuate SV waves passing through them. These anomalies lie beneath the Indian Wells Valley 30 km south...

143

A Shallow Attenuating Anomaly Inside The Ring Fracture Of The...  

Open Energy Info (EERE)

Shallow Attenuating Anomaly Inside The Ring Fracture Of The Valles Caldera, New Mexico Jump to: navigation, search OpenEI Reference LibraryAdd to library Journal Article: A Shallow...

144

Pressure dependence of sound attenuation in the Pacific Ocean  

Science Journals Connector (OSTI)

Measurements of the attenuation of sound at a nominal frequency of 75 kHz have been made over vertical and horizontal acoustic paths located between depths of 700 and 3400 m in the Pacific Ocean. Results indicate that the equation used to predict attenuation overestimates the values actually encountered at these frequencies and depths. (Compare calculated values of 27.3 and 22.7 dB/km to measured values of 19.9±0.5 and 13.3±0.5 dB/km at depths of 910 and 3350 m respectively.) The measurements definitely establish the decrease of attenuation with increasing pressure. However the magnitude of the pressure coefficient of attenuation is almost twice as large as previously suspected (12.3±1.1×10?4/bar or approximately 12.3×10?4/atm compared to 6.54×10?4/atm).

H. F. Bezdek

1973-01-01T23:59:59.000Z

145

Suppression of ring artefacts when tomographing anisotropically attenuating samples  

Science Journals Connector (OSTI)

An intensity normalization technique is proposed to suppress ring artefacts of varying strength. The method was applied to an elongated sample in a monochromatic beam and to a sample with highly attenuated parts in a white beam.

Titarenko, S.

2011-04-02T23:59:59.000Z

146

Accurate characterization and improvement of GaAs microstrip attenuation  

E-Print Network (OSTI)

Mason Carroll, B. S. , Rose-Hulman Institute of Technology Chair of Advisory Committee: Dr. Kai Chang Microstrip transmission lines are widely used in microv, ave circuits. The high frequencies cause the microstrip characteristics, especially... OF CONTENTS . . LIST OF FIGURES LIST OF TABLES. . CHAPTER I INTRODUCTION . . I. A Introduction. I. B Thesis Research Il GaAs MICROSTRlp ATTENUATION . II. A Characterization ol'Transmission Line Attenuation. . . . II. A. I Introduction. II. A. 2...

Carroll, James Mason

2012-06-07T23:59:59.000Z

147

Wave energy attenuation and shoreline alteration characteristics of submerged breakwaters  

E-Print Network (OSTI)

WAVE ENERGY ATTENUATION AND SHORELINE ALTERATION CHARACTERISTICS OF SUBMERGED BREAKWATERS A Thesis by KATHERINE MARGARET KRAFFT Submitted to the Office of Graduate Studies of Texas AIM University in partial fulfillment of the requirements... for the degree of MASTER OF SCIENCE August 1993 Major Subject: Ocean Engineering WAVE ENERGY ATTENUATION AND SHORELINE ALTERATION CHARACTERISTICS OF SUBMERGED BREAKWATERS A Thesis by KATHERINE MARGARET KRAFFT Approved as to style and content by: John...

Krafft, Katherine Margaret

1993-01-01T23:59:59.000Z

148

The mass  

Science Journals Connector (OSTI)

The mass of the charged Higgs boson at the 1-loop level is investigated, assuming the CP symmetry to be violated explicitly in the Higgs sector of the minimal supersymmetric standard model (MSSM). It is found that there is a parameter region of the MSSM where the presence of explicit CP violation in the Higgs sector yields negative radiative corrections to the charged Higgs boson mass. Thus, the charged Higgs boson in the MSSM may have as low a mass as 60 GeV at the 1-loop level, if the CP symmetry is violated. This lower bound may be improved by the Higgs search at LEP2, which imposes experimental constraints on the charged Higgs mass, as well as on the masses of the neutral Higgs bosons. Hence, LEP2 can constrain experimentally the charged Higgs mass to be not smaller than 109 GeV under our assumption. In addition, it sets 75 GeV as the lower bound on the mass of the lightest neutral Higgs boson, and 84 GeV for that of the next-to-lightest neutral Higgs boson.

Seung Woo Ham; Sun Kun Oh; Eun Jong Yoo; Hyun Kyu Lee

2001-01-01T23:59:59.000Z

149

Automatic detection of bone fragments in poultry using multi-energy x-rays  

DOE Patents (OSTI)

At least two linear arrays of x-ray detectors are placed below a conveyor belt in a poultry processing plant. Multiple-energy x-ray sources illuminate the poultry and are detected by the detectors. Laser profilometry is used to measure the poultry thickness as the x-ray data is acquired. The detector readout is processed in real time to detect the presence of small highly attenuating fragments in the poultry, i.e., bone, metal, and cartilage.

Gleason, Shaun S. (Knoxville, TN); Paulus, Michael J. (Knoxville, TN); Mullens, James A. (Knoxville, TN)

2002-04-09T23:59:59.000Z

150

Seismic Velocity And Attenuation Structure Of The Geysers Geothermal Field,  

Open Energy Info (EERE)

Velocity And Attenuation Structure Of The Geysers Geothermal Field, Velocity And Attenuation Structure Of The Geysers Geothermal Field, California Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: Seismic Velocity And Attenuation Structure Of The Geysers Geothermal Field, California Details Activities (1) Areas (1) Regions (0) Abstract: The Geysers geothermal field is located in northern California and is one of the world's largest producers of electricity from geothermal energy. A key resource management issue at this field is the distribution of fluid in the matrix of the reservoir rock. In this paper, we interpret seismic compressional-wave velocity and quality quotient (Q) data at The Geysers in terms of the geologic structure and fluid saturation in the reservoir. Our data consist of waveforms from approximately 300

151

Coronal structure of low-mass stars  

Science Journals Connector (OSTI)

......structure of low-mass stars Pauline Lang...loss in the stellar wind and X-ray emission...use reconstructed maps of the radial magnetic...strong as the stellar mass decreases, while...magnitude of the open (wind-bearing) magnetic...either rotational velocity or Rossby number......

Pauline Lang; Moira Jardine; Jean-François Donati; Julien Morin; Aline Vidotto

2012-08-01T23:59:59.000Z

152

X-ray focal spot locating apparatus and method  

DOE Patents (OSTI)

An X-ray beam finder for locating a focal spot of an X-ray tube includes a mass of X-ray opaque material having first and second axially-aligned, parallel-opposed faces connected by a plurality of substantially identical parallel holes perpendicular to the faces and a film holder for holding X-ray sensitive film tightly against one face while the other face is placed in contact with the window of an X-ray head.

Gilbert, Hubert W. (Cedar Crest, NM)

1985-07-30T23:59:59.000Z

153

High speed x-ray beam chopper  

DOE Patents (OSTI)

A fast, economical, and compact x-ray beam chopper with a small mass and a small moment of inertia whose rotation can be synchronized and phase locked to an electronic signal from an x-ray source and be monitored by a light beam is disclosed. X-ray bursts shorter than 2.5 microseconds have been produced with a jitter time of less than 3 ns.

McPherson, Armon (Oswego, IL); Mills, Dennis M. (Naperville, IL)

2002-01-01T23:59:59.000Z

154

Frequency-dependent attenuation and elasticity in unconsolidated earth materials: effect of damping  

E-Print Network (OSTI)

We use the Discrete Element Method (DEM) to understand the underlying attenuation mechanism in granular media, with special applicability to the measurements of the so-called effective mass developed earlier. We consider that the particles interact via Hertz-Mindlin elastic contact forces and that the damping is describable as a force proportional to the velocity difference of contacting grains. We determine the behavior of the complex-valued normal mode frequencies using 1) DEM, 2) direct diagonalization of the relevant matrix, and 3) a numerical search for the zeros of the relevant determinant. All three methods are in strong agreement with each other. The real and the imaginary parts of each normal mode frequency characterize the elastic and the dissipative properties, respectively, of the granular medium. We demonstrate that, as the interparticle damping, $\\xi$, increases, the normal modes exhibit nearly circular trajectories in the complex frequency plane and that for a given value of $\\xi$ they all lie ...

Hu, Yanqing; Valenza, John J; Johnson, David L

2014-01-01T23:59:59.000Z

155

Muscle power attenuation by tendon during energy dissipation  

Science Journals Connector (OSTI)

...would allow tendon to act as a power attenuator, which would be...and (iii) a reduced rate of power transfer to the muscle fascicle relative to power into the MTU. 2. Material...the leg (tibiotarsus) and foot (tarsometatarsus) bones to...

2012-01-01T23:59:59.000Z

156

Viscous attenuation of a detonation wave propagating in a channel  

E-Print Network (OSTI)

Viscous attenuation of a detonation wave propagating in a channel P. Ravindran1 , R. Bellini1 , T of a detonation wave in a two-dimensional channel is simulated by an Euler and a Navier-Stokes solver. Transport arising from viscous drag. 1 Introduction The propagation of a detonation wave remains one

Texas at Arlington, University of

157

Effects of Rain Attenuation on Satellite Video Transmission  

E-Print Network (OSTI)

. The effectiveness of site diversity as a mitigation technique is also studied. II. WEATHER EFFECTS Satellite path is the major weather effect of concern for satellite communications operating at frequencies aboveEffects of Rain Attenuation on Satellite Video Transmission Yee Hui Lee and Stefan Winkler Nanyang

Winkler, Stefan

158

Attenuation character of seismic waves in Sikkim Himalaya  

Science Journals Connector (OSTI)

......seismic waves in Sikkim Himalaya Pinki Hazarika 1 M. Ravi Kumar 1 Dinesh Kumar 2 1 National Geophysical Research Institute (CSIR...L24307. doi:10.1029/2009GL041081. Chopra S. , Kumar D., Rastogi B.K. Attenuation of high frequency......

Pinki Hazarika; M. Ravi Kumar; Dinesh Kumar

159

NETL: Utilization Projects - Speciation and Attenuation of Arsenic and  

NLE Websites -- All DOE Office Websites (Extended Search)

Speciation and Attenuation of Arsenic and Selenium at Coal Combustion By-Product Management Facilities Speciation and Attenuation of Arsenic and Selenium at Coal Combustion By-Product Management Facilities The overall objective of this project is to evaluate the impact of key constituents captured from power plant air streams (arsenic, selenium and mercury) on the disposal and utilization of coal combustion by-products. Specific objectives of the project are: 1) to develop a comprehensive database of field leachate concentrations at a wide range of CCB management sites (about 25 sites), including speciation of arsenic and selenium, and low-detection limit analyses for mercury; and 2) to perform detailed evaluations of the release and attenuation of arsenic and selenium species at 3 CCB sites. The fundamental or mechanistic data to reliably model many of the inorganics in CCB leachate are lacking. There is a large degree of uncertainty in the initial leachate concentrations, long-term leaching characteristics of CCBs, and the attenuation coefficients typically used in groundwater transport models. As a result, the model simulations are either highly conservative, or they can be manipulated to obtain almost any desired result. This research project will develop a coherent field leachate database and soil attenuation coefficients for improved modeling and evaluation of the potential for groundwater impacts at CCB management facilities. The work is focused on speciation of four key constituents at CCB sites: arsenic, selenium, chromium, and mercury. The proposed work will help to narrow the uncertainties in the range of values of these critical inputs and improve the accuracy of the modeling results.

160

Method for attenuating seismic shock from detonating explosive in an in situ oil shale retort  

DOE Patents (OSTI)

In situ oil shale retorts are formed in formation containing oil shale by excavating at least one void in each retort site. Explosive is placed in a remaining portion of unfragmented formation within each retort site adjacent such a void, and such explosive is detonated in a single round for explosively expanding formation within the retort site toward such a void for forming a fragmented permeable mass of formation particles containing oil shale in each retort. This produces a large explosion which generates seismic shock waves traveling outwardly from the blast site through the underground formation. Sensitive equipment which could be damaged by seismic shock traveling to it straight through unfragmented formation is shielded from such an explosion by placing such equipment in the shadow of a fragmented mass in an in situ retort formed prior to the explosion. The fragmented mass attenuates the velocity and magnitude of seismic shock waves traveling toward such sensitive equipment prior to the shock wave reaching the vicinity of such equipment.

Studebaker, Irving G. (Grand Junction, CO); Hefelfinger, Richard (Grand Junction, CO)

1980-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "ray mass attenuation" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


161

A Field Study of Seismic Attenuation In Layered Sedimentary Rocks—II. Crosshole Data  

Science Journals Connector (OSTI)

......Carboniferous limestones, shales and sandstones. Estimates...at least in part, to anisotropic intrinsic attenuation...Carboniferous limestones, shales and sandstones. Estimates...at least in part, to anisotropic intrinsic attenuation......

I. R. Portsmouth; M. H. Worthington; J. P. Neep

1993-04-01T23:59:59.000Z

162

E-Print Network 3.0 - attenuated total internal Sample Search...  

NLE Websites -- All DOE Office Websites (Extended Search)

cannot be regulated, which requires the shade and tilt attenuation... t for this agent's solar panel, reduced by the attenuation from clouds (C(t)), shade (S(t, l)) and the tilt...

163

Reactive Transport Modeling of Natural Attenuation in Stormwater Bioretention Cells and Under Land Application of Wastewater  

E-Print Network (OSTI)

Natural attenuation is a cost effective method to treat wastewater applied into soil. The natural attenuation process includes diffusion, dispersion, microbial activity, oxidation, mineral precipitation, sorption, and ion exchange to mitigate...

Zhang, Jingqiu

2014-04-29T23:59:59.000Z

164

E-Print Network 3.0 - attenuates age-related decrements Sample...  

NLE Websites -- All DOE Office Websites (Extended Search)

in the case of power-time law creep an anomalous attenuation decrease is induced by the first stress decrement... of attenuation during the first decrement in the case ... Source:...

165

Experimentally Based Estimates of Relations between X-Band Radar Signal Attenuation Characteristics and Differential Phase in Rain  

Science Journals Connector (OSTI)

Correcting observed polarimetric radar variables for attenuation and differential attenuation effects in rain is important for meteorological applications involving measurements at attenuating frequencies such as those at X band. The results of ...

Sergey Y. Matrosov; Patrick C. Kennedy; Robert Cifelli

2014-11-01T23:59:59.000Z

166

Attenuation of high energy multi-hadron systems leptoproduced in nuclear matter  

Science Journals Connector (OSTI)

Attenuation of groups of high energy particles leptoproduced in nuclear matter is calculated in terms of parameters...

A. Bia?as; J. Czy?ewski

1990-01-01T23:59:59.000Z

167

E-Print Network 3.0 - attenuation map derived Sample Search Results  

NLE Websites -- All DOE Office Websites (Extended Search)

- Department of Systems and Computer Engineering, Carleton University Collection: Computer Technologies and Information Sciences 30 BOREHOLE RADAR ATTENUATION-DIFFERENCE...

168

?-ray astronomy  

Science Journals Connector (OSTI)

... THE title on the cover of this book reads Gamma-Ray Astronomy but inside a subtitle, Nuclear Transition Region has been added. This uncertainty as to ... an uneven quality to what is, otherwise, a valuable contribution to this field of astronomy.

R. R. Hillier

1977-05-26T23:59:59.000Z

169

Mass of Cu-57  

E-Print Network (OSTI)

the extension of these systematics to higher Z. If the 3 =57 nuclei have true single particle low-lying states, the Cu beta decay rates determine the 2p3/2 +2p3/2 and 2p 3/2 ~2p ~ &2 Gamow-Teller matrix elements, providing a measure of Gamow... with A ~ 56 (Ref. 3) and possibly for the time evolu- tion of cosmic x-ray bursts. Cu has been observed in the Cu~ Ni+e++v, and Ni( Li, He} Cu reactions. The former study found the Cu mass excess to be ?47.34(13) MeV and deter- mined its beta decay...

Gagliardi, Carl A.; Semon, D. R.; Tribble, Robert E.; Vanausdeln, L. A.

1986-01-01T23:59:59.000Z

170

Attenuation and source properties at the Coso Geothermal Area, California |  

Open Energy Info (EERE)

source properties at the Coso Geothermal Area, California source properties at the Coso Geothermal Area, California Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: Attenuation and source properties at the Coso Geothermal Area, California Details Activities (1) Areas (1) Regions (0) Abstract: We use a multiple-empirical Green's function method to determine source properties of small (M -0.4 to 1.3) earthquakes and P- and S-wave attenuation at the Coso Geothermal Field, California. Source properties of a previously identified set of clustered events from the Coso geothermal region are first analyzed using an empirical Green's function (EGF) method. Stress-drop values of at least 0.5-1 MPa are inferred for all of the events; in many cases, the corner frequency is outside the usable bandwidth, and the stress drop can only be constrained as being higher than

171

CALCULATION OF PULSED KICKER MAGNETIC FIELD ATTENUATION INSIDE BEAM CHAMBERS  

NLE Websites -- All DOE Office Websites (Extended Search)

CALCULATION OF PULSED KICKER MAGNETIC FIELD ATTENUATION CALCULATION OF PULSED KICKER MAGNETIC FIELD ATTENUATION INSIDE BEAM CHAMBERS S. H. Kim January 8, 2001 1. Introduction and Summary The ceramic beam chambers in the sections of the kicker magnets for the beam injection and extraction in the Advanced Photon Source (APS) are made of alumina. The inner surface of the ceramic chamber is coated with a conductive paste. The choice of coating thickness is intended to reduce the shielding of the pulsed kicker magnetic field while containing the electromagnetic fields due to the beam bunches inside the chamber, and minimize the Ohmic heating due to the fields on the chamber [1]. The thin coating generally does not give a uniform surface resistivity for typical dimensions of the ceramic chambers in use. The chamber cross section is a circular or

172

Attenuation structure of Coso geothermal area, California, from wave pulse  

Open Energy Info (EERE)

structure of Coso geothermal area, California, from wave pulse structure of Coso geothermal area, California, from wave pulse widths Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: Attenuation structure of Coso geothermal area, California, from wave pulse widths Details Activities (1) Areas (1) Regions (0) Abstract: Pulse width data are used to invert for attenuation structure in the Coso geothermal area, California. The dataset consists of pulse width measurements of 838 microseismic events recorded on a seismic array of 16 downhole stations between August 1993 and March 1994. The quality factor Q correlates well with surface geology and surface heat flow observations. A broad region of low Q (≈ 30 to 37) is located at 0.5 to 1.2 km in depth below Devil's Kitchen, Nicol Prospects, and Coso Hot Springs. A vertical,

173

Plasma-parameter measurements using neutral-particle-beam attenuation  

SciTech Connect

Intense and energetic neutral-particle-beam injection used for fueling or heating magnetically confined, controlled-fusion experimental plasmas can also provide diagnostic measurements of the plasmas. The attenuation of an atomic beam (mainly from charge-exchange and ionization interactions) when passing through a plasma gives the plasma line density. Orthogonal arrays of highly collimated detectors of the secondary-electron-emission type have been used in magnetic-mirror experiments to measure neutral-beam attenuation along chords through the plasma volume at different radial and axial positions. The radial array is used to infer the radial plasma-density profile; the axial array, to infer the axial plasma-density profile and the ion angular distribution at the plasma midplane.

Foote, J.H.; Molvik, A.W.; Turner, W.C.

1982-07-07T23:59:59.000Z

174

NATURAL ATTENUATION FOR ECOSYSTEM RESTORATION IN NY/NJ HARBOR  

SciTech Connect

We have investigated the feasibility of using natural attenuation methods for ecosystem restoration in New York/New Jersey Harbor. Measurements were made of the most probable number of sulfate-reducing bacteria (SRB) in native sediments and in samples, which had been supplemented with an appropriate electron donor and electron acceptor. The results showed that the activity of the endogenous microbial population in the native sediment was high enough to make possible adequate chemical transformation rates. The bioavailability of the zinc in the sediments was measured using the BIOMET biosensor technique. The bioavailability of the zinc was effectively eliminated following the microbial activities. We concluded that natural attenuation could be used effectively in treating sediments from Newark Bay and surrounding waters and that the resultant materials could likely be used in environmental restoration projects of the type proposed for construction in South Kearny, NJ.

VAN DER LELIE,D.JONES,K.W.REID-GREEN,J.D.STERN,E.A.

2003-12-31T23:59:59.000Z

175

Neutrinos from Gamma Ray Bursts  

E-Print Network (OSTI)

We show that the detection of neutrinos from a typical gamma ray burst requires a kilometer-scale detector. We argue that large bursts should be visible with the neutrino telescopes under construction. We emphasize the 3 techniques by which neutrino telescopes can perform this search: by triggering on i) bursts of muons from muon neutrinos, ii) muons from air cascades initiated by high energy gamma rays and iii) showers made by relatively low energy ($\\simeq 100\\,\\mev$) electron neutrinos. Timing of neutrino-photon coincidences may yield a measurement of the neutrino mass to order $10^{-5}$~eV, an interesting range in light of the solar neutrino anomaly.

F. Halzen; G. Jaczko

1996-02-07T23:59:59.000Z

176

Low?frequency attenuation in the Pacific Ocean  

Science Journals Connector (OSTI)

There is increasing evidence that the low?frequency sound absorption in the Pacific is less than that in the Atlantic. Thorp's original empirical equation was based largely on North Atlantic data. The origin of his excess attenuation anomaly has recently been identified as a boron relaxation. A compilation of available Pacific data appears to show roughly one?half the boron absorption predicted by Thorp which suggests differences in the chemistry of the oceans.

R. H. Mellen; D. G. Browning

1975-01-01T23:59:59.000Z

177

Investigation of frequency dependent attenuation in a vertical seismic profile  

E-Print Network (OSTI)

and the results analyzed. Use of monitor geophones allows corrections to be made for source variability. Correction for interference by employment of syn- thetic seismogram modeling is attempted, but without success. The synthetic modeling does reveal... of the Problem. Concepts. CHAPTER II ? SEISMIC DATA PROCESSING. . . 12 The VSP Data Set. 12 Cumulative Attenuation Measurements. 23 Variance. 30 CHAPTER III ? SYNTHETIC SEISMOGRAMS. 35 Data Processing. 35 Interference Correction. 41 CHAPTER IV...

Zeitvogel, Mark Evan

2012-06-07T23:59:59.000Z

178

Natural attenuation of fuel hydrocarbon contaminants: Hydraulic conductivity dependency of biodegradation rates in a field case study  

SciTech Connect

Two biodegradation models are developed to represent natural attenuation of fuel-hydrocarbon contaminants as observed in a comprehensive natural-gradient tracer test in a heterogeneous aquifer on the Columbus Air Force Base in Mississippi. The first, a first-order mass loss model, describes the irreversible losses of BTEX and its individual components, i.e., benzene (B), toluene (T), ethyl benzene (E), and xylene (X). The second, a reactive pathway model, describes sequential degradation pathways for BTEX utilizing multiple electron acceptors, including oxygen, nitrate, iron and sulfate, and via methanogenesis. The heterogeneous aquifer is represented by multiple hydraulic conductivity (K) zones delineated on the basis of numerous flowmeter K measurements. A direct propagation artificial neural network (DPN) is used as an inverse modeling tool to estimate the biodegradation rate constants associated with each of the K zones. In both the mass loss model and the reactive pathway model, the biodegradation rate constants show an increasing trend with the hydraulic conductivity. The finding of correlation between biodegradation kinetics and hydraulic conductivity distributions is of general interest and relevance to characterization and modeling of natural attenuation of hydrocarbons in other petroleum-product contaminated sites.

Lu, Guoping; Zheng, Chunmiao

2003-07-15T23:59:59.000Z

179

Natural Attenuation of Fuel Hydrocarbon Contaminants: Correlation of Biodegradation with Hydraulic Conductivity in a Field Case Study  

SciTech Connect

Two biodegradation models are developed to represent natural attenuation of fuel-hydrocarbon contaminants as observed in a comprehensive natural-gradient tracer test in a heterogeneous aquifer on the Columbus Air Force Base in Mississippi, USA. The first, a first-order mass loss model, describes the irreversible losses of BTEX and its individual components, i.e., benzene (B), toluene (T), ethyl benzene (E), and xylene (X). The second, a reactive pathway model, describes sequential degradation pathways for BTEX utilizing multiple electron acceptors, including oxygen, nitrate, iron and sulfate, and via methanogenesis. The heterogeneous aquifer is represented by multiple hydraulic conductivity (K) zones delineated on the basis of numerous flowmeter K measurements. A direct propagation artificial neural network (DPN) is used as an inverse modeling tool to estimate the biodegradation rate constants associated with each of the K zones. In both the mass loss model and the reactive pathway model, the biodegradation rate constants show an increasing trend with the hydraulic conductivity. The finding of correlation between biodegradation kinetics and hydraulic conductivity distributions is of general interest and relevance to characterization and modeling of natural attenuation of hydrocarbons in other petroleum-product contaminated sites.

Lu, Guoping; Zheng, Chunmiao

2003-10-15T23:59:59.000Z

180

X-ray lithography using holographic images  

DOE Patents (OSTI)

Methods for forming X-ray images having 0.25 {micro}m minimum line widths on X-ray sensitive material are presented. A holographic image of a desired circuit pattern is projected onto a wafer or other image-receiving substrate to allow recording of the desired image in photoresist material. In one embodiment, the method uses on-axis transmission and provides a high flux X-ray source having modest monochromaticity and coherence requirements. A layer of light-sensitive photoresist material on a wafer with a selected surface is provided to receive the image(s). The hologram has variable optical thickness and variable associated optical phase angle and amplitude attenuation for transmission of the X-rays. A second embodiment uses off-axis holography. The wafer receives the holographic image by grazing incidence reflection from a hologram printed on a flat metal or other highly reflecting surface or substrate. In this second embodiment, an X-ray beam with a high degree of monochromaticity and spatial coherence is required. 15 figs.

Howells, M.S.; Jacobsen, C.

1997-03-18T23:59:59.000Z

Note: This page contains sample records for the topic "ray mass attenuation" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


181

X-ray lithography using holographic images  

DOE Patents (OSTI)

Methods for forming X-ray images having 0.25 .mu.m minimum line widths on X-ray sensitive material are presented. A holgraphic image of a desired circuit pattern is projected onto a wafer or other image-receiving substrate to allow recording of the desired image in photoresist material. In one embodiment, the method uses on-axis transmission and provides a high flux X-ray source having modest monochromaticity and coherence requirements. A layer of light-sensitive photoresist material on a wafer with a selected surface is provided to receive the image(s). The hologram has variable optical thickness and variable associated optical phase angle and amplitude attenuation for transmission of the X-rays. A second embodiment uses off-axis holography. The wafer receives the holographic image by grazing incidence reflection from a hologram printed on a flat metal or other highly reflecting surface or substrate. In this second embodiment, an X-ray beam with a high degree of monochromaticity and spatial coherence is required.

Howells, Malcolm S. (Berkeley, CA); Jacobsen, Chris (Sound Beach, NY)

1997-01-01T23:59:59.000Z

182

Anomalous isotopic composition of cosmic rays  

SciTech Connect

Recent measurements of nonsolar isotopic patterns for the elements neon and (perhaps) magnesium in cosmic rays are interpreted within current models of stellar nucleosynthesis. One possible explanation is that the stars currently responsible for cosmic-ray synthesis in the Galaxy are typically super-metal-rich by a factor of two to three. Other possibilities include the selective acceleration of certain zones or masses of supernovas or the enhancement of /sup 22/Ne in the interstellar medium by mass loss from red giant stars and planetary nebulas. Measurements of critical isotopic ratios are suggested to aid in distinguishing among the various possibilities. Some of these explanations place significant constraints on the fraction of cosmic ray nuclei that must be fresh supernova debris and the masses of the supernovas involved. 1 figure, 3 tables.

Woosley, S.E.; Weaver, T.A.

1980-06-20T23:59:59.000Z

183

Optimized Volumetric Scanning for X-Ray Array Sources  

SciTech Connect

Non-destructive evaluation (NDE) is the science and technology of determining non-invasively the internal structure of manufactured parts, objects, and materials. NDE application areas include medicine, industrial manufacturing, military, homeland security, and airport luggage screening. X-ray measurement systems are most widely used because of their ability to image through a wide range of material densities (from human tissue in medical applications to the dense materials of weapon components). Traditional x-ray systems involve a single source and detector system that rotate and/or translate about the object under evaluation. At each angular location, the source projects x-rays through the object. The rays undergo attenuation proportional to the density of the object's constitutive material. The detector records a measure of the attenuation. Mathematical algorithms are used to invert the forward attenuated ray projection process to form images of the object. This is known as computed tomography (CT). In recent years, the single-source x-ray NDE systems have been generalized to arrays of x-ray sources. Array sources permit multiple views of the object with fewer rotations and translations of the source/detector system. The spatially diverse nature of x-ray array sources has the potential of reducing data collection time, reducing imaging artifacts, and increasing the resolution of the resultant images. Most of the existing CT algorithms were not derived from array source models with a spatially diverse set of viewing perspectives. Single-source x-ray CT data collection, processing, and imaging methods and algorithms are not applicable when the source location is expanded from one dimension (a rotating and/or translating point source) to two (a rotating and/or translating array). They must be reformulated. The goal of this project is to determine the applicability of x-ray array sources to problems of interest to LLNL and its customers. It is believed array source data collection will be faster while yielding higher resolution reconstructions with fewer artifacts. There are three tasks in the research: (1) Develop forward array source analytic and computational models; (2) Research and develop array source reconstruction algorithms; and (3) Perform experiments.

Lehman, S K; Foudray, A M; Wang, A; Kallman, J S; Martz, H

2009-09-29T23:59:59.000Z

184

Source attenuating HVAC equipment—Just the facts  

Science Journals Connector (OSTI)

Current classroom designs range from NC 63 to NC 25. The ASA/ANSI 12.60 Classroom Standard sets a relatively low background sound requirement for classrooms. Achieving 12.60 levels economically requires the maximum in source sound attenuation. This paper will provide a manufacturer’s perspective on current and low noiseHVAC products and the resulting classroomsound levels. Predictive acoustics software will be used to predict the space sound power level and some indication of equipment cost will be provided in order to assist designers in what is the best approach to low noiseclassroom design.

2004-01-01T23:59:59.000Z

185

High-power radio-frequency attenuation device  

DOE Patents (OSTI)

A resistor device for attenuating radio frequency power includes a radio frequency conductor connected to a series of fins formed of high relative magnetic permeability material. The fins are dimensional to accommodate the skin depth of the current conduction therethrough, as well as an inner heat conducting portion where current does not travel. Thermal connections for air or water cooling are provided for the inner heat conducting portions of each fin. Also disclosed is a resistor device to selectively alternate unwanted radio frequency energy in a resonant cavity.

Kerns, Q.A.; Miller, H.W.

1981-12-30T23:59:59.000Z

186

On the exponential power law for low frequency attenuation in shallow water  

Science Journals Connector (OSTI)

Reviews of measured shallow-water sound transmission over sandy-silty bottoms show the intrinsic attenuation for low frequencies (energy downwards out of the waveguide is considered. Since the intrinsic attenuation and the apparent attenuation due to shear wave conversion are small the observed attenuation can have a different frequency dependence. If the removal of energy from the field due to shear wave conversion is comparable to the intrinsic attenuation at the lower frequencies but less than the intrinsic attenuation at the higher frequencies; the inferred frequency dependence can be less than quadratic. Inversions with fluid sediments account for this effect by the site-specific factors that accounts for the loss of energy from the compressible field due shear wave conversion.

William M. Carey

2008-01-01T23:59:59.000Z

187

The Gas Flow from the Gas Attenuator to the Beam Line  

SciTech Connect

The gas leak from the gas attenuator to the main beam line of the Linac Coherent Light Source has been evaluated, with the effect of the Knudsen molecular beam included. It has been found that the gas leak from the gas attenuator of the present design, with nitrogen as a working gas, does not exceed 10{sup -5} torr x l/s even at the highest pressure in the main attenuation cell (20 torr).

Ryutov, D.D.

2010-12-03T23:59:59.000Z

188

E-Print Network 3.0 - attenuates pancreatic cancer Sample Search...  

NLE Websites -- All DOE Office Websites (Extended Search)

pancreatic cancer Search Powered by Explorit Topic List Advanced Search Sample search results for: attenuates pancreatic cancer Page: << < 1 2 3 4 5 > >> 1 RBBP9: A...

189

Inverse scattering series for multiple attenuation: An example with surface and internal multiples  

SciTech Connect

A multiple attenuation method derived from an inverse scattering series is described. The inversion series approach allows a separation of multiple attenuation subseries from the full series. The surface multiple attenuation subseries was described and illustrated in Carvalho et al. (1991, 1992). The internal multiple attenuation method consists of selecting the parts of the odd terms that are associated with removing only multiply reflected energy. The method, for both types of multiples, is multidimensional and does not rely on periodicity or differential moveout, nor does it require a model of the reflectors generating the multiples. An example with internal and surface multiples will be presented.

Araujo, F.V. [PPPG/Federal Univ. of Bahia, Salvador (Brazil); Weglein, A.B. [Schlumberger Cambridge Research (United Kingdom); Carvalho, P.M. [Petrobras SA, Rio de Janeiro (Brazil); Stolt, R.H.

1994-12-31T23:59:59.000Z

190

E-Print Network 3.0 - attenuated live infectious Sample Search...  

NLE Websites -- All DOE Office Websites (Extended Search)

Live, attenuated coccidial vaccines... . Infectious laryngotracheitis (ILT) 6. Visceral gout 7. Fatty liver 8. Cloacal prolapse 9. Osteomalacia 10... Infection (Colibacillosis)...

191

E-Print Network 3.0 - attenuates cognitive impairment Sample...  

NLE Websites -- All DOE Office Websites (Extended Search)

cognitive impairment Search Powered by Explorit Topic List Advanced Search Sample search results for: attenuates cognitive impairment Page: << < 1 2 3 4 5 > >> 1 Healthy Brain...

192

E-Print Network 3.0 - attenuation coefficient measurements Sample...  

NLE Websites -- All DOE Office Websites (Extended Search)

and attenuation in limestones in the laboratory L. Adam and M. Batzle, Center for Rock Abuse, Colorado School of Mines Summary: for reservoir characterization. We measure...

193

E-Print Network 3.0 - attenuated total reflectance-fourier Sample...  

NLE Websites -- All DOE Office Websites (Extended Search)

(AA) monomerswas visualized and analyzed using attenuated total reflection-Fourier transform Source: Freger, Viatcheslav "Slava" - Zuckerberg Institute for Water Research,...

194

E-Print Network 3.0 - attenuated total reflection-fourier Sample...  

NLE Websites -- All DOE Office Websites (Extended Search)

(AA) monomerswas visualized and analyzed using attenuated total reflection-Fourier transform Source: Freger, Viatcheslav "Slava" - Zuckerberg Institute for Water Research,...

195

E-Print Network 3.0 - attenuation mna--programmatic technical...  

NLE Websites -- All DOE Office Websites (Extended Search)

with the DCC and MC simulations for SPECT imaging. Summary: of the attenuated Radon Transform (with the Novikov formula or more realistically with algebraic technics including......

196

E-Print Network 3.0 - attenuate renal ischaemia-reperfusion Sample...  

NLE Websites -- All DOE Office Websites (Extended Search)

; Biology and Medicine 82 Kidney International, Vol. 63 (2003), pp. 17851790 Effect of green tea extract on cardiac hypertrophy following Summary: attenuate the devel- that the...

197

E-Print Network 3.0 - attenuate postischemic brain Sample Search...  

NLE Websites -- All DOE Office Websites (Extended Search)

postischemic brain Search Powered by Explorit Topic List Advanced Search Sample search results for: attenuate postischemic brain Page: << < 1 2 3 4 5 > >> 1 Permanent Reduction of...

198

E-Print Network 3.0 - attenuates sulindac sulfide-mediated Sample...  

NLE Websites -- All DOE Office Websites (Extended Search)

Zhu1 and Ilya Tsvankin1 ABSTRACT Directionally... dependent attenuation in transversely iso- tropic (TI) media can influence significantly the body... a con- sistent analytic...

199

E-Print Network 3.0 - attenuate white matter Sample Search Results  

NLE Websites -- All DOE Office Websites (Extended Search)

white matter Search Powered by Explorit Topic List Advanced Search Sample search results for: attenuate white matter Page: << < 1 2 3 4 5 > >> 1 Parametric Transverse Relaxation...

200

E-Print Network 3.0 - attenuated oral vaccine Sample Search Results  

NLE Websites -- All DOE Office Websites (Extended Search)

J Infect Dis 1995... -15, a live attenuated ... Source: Mekalanos, John - Department of Microbiology and Molecular Genetics, Harvard University Collection: Biology and Medicine...

Note: This page contains sample records for the topic "ray mass attenuation" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


201

E-Print Network 3.0 - attenuated live vaccine Sample Search Results  

NLE Websites -- All DOE Office Websites (Extended Search)

of a live attenuated HIV... vaccine in macaques have clearly demonstrated the ... Source: Gilbert, Peter - Fred Hutchinson Cancer Research Center & Department of Biostatistics,...

202

E-Print Network 3.0 - attenuated human rotavirus Sample Search...  

NLE Websites -- All DOE Office Websites (Extended Search)

have clearly demonstrated the reality of reversion of attenuated virus to ... Source: Gilbert, Peter - Fred Hutchinson Cancer Research Center & Department of Biostatistics,...

203

E-Print Network 3.0 - attenuated vaccine strains Sample Search...  

NLE Websites -- All DOE Office Websites (Extended Search)

404... attenuated RSV vaccine for the ... Source: Crowe Jr, James E. - Department of Microbiology and Immunology, Vanderbilt University Collection: Biology and Medicine 23...

204

E-Print Network 3.0 - attenuates murine bleomycin-induced Sample...  

NLE Websites -- All DOE Office Websites (Extended Search)

<< < 1 2 3 4 5 > >> 21 Name Sherry D. Fleming Title Assistant Professor Summary: esterase inhibitor attenuates murine mesenteric ischemiareperfusion induced local organ injury. J....

205

E-Print Network 3.0 - attenuated sl3-3 murine Sample Search Results  

NLE Websites -- All DOE Office Websites (Extended Search)

Biology and Medicine 2 Name Sherry D. Fleming Title Assistant Professor Summary: esterase inhibitor attenuates murine mesenteric ischemiareperfusion induced local organ injury. J....

206

E-Print Network 3.0 - attenuates cardiac allograft Sample Search...  

NLE Websites -- All DOE Office Websites (Extended Search)

of serum-deprivation would be beneficial to attenuating the progression of cardiac... -chitosan-QHREDGS hydrogel may markedly improve cardiac regeneration by cell therapy....

207

E-Print Network 3.0 - attenuate hydrogen peroxide Sample Search...  

NLE Websites -- All DOE Office Websites (Extended Search)

hydrogen peroxide Search Powered by Explorit Topic List Advanced Search Sample search results for: attenuate hydrogen peroxide Page: << < 1 2 3 4 5 > >> 1 SHORT COMMUNICATION Ned...

208

E-Print Network 3.0 - attenuates trail-induced apoptosis Sample...  

NLE Websites -- All DOE Office Websites (Extended Search)

attenuates trail-induced apoptosis Page: << < 1 2 3 4 5 > >> 1 Combining naturally occurring polyphenols with TNF-Related Apoptosis-Inducing Ligand (TRAIL): a promising approach...

209

E-Print Network 3.0 - administration attenuates tissue Sample...  

NLE Websites -- All DOE Office Websites (Extended Search)

Engineering ; Biology and Medicine 14 Effect of a putative ER antagonist, MPP, on food intake in cycling and ovariectomized rats Summary: , MPP failed to attenuate the...

210

E-Print Network 3.0 - attenuates ionizing radiation-induced Sample...  

NLE Websites -- All DOE Office Websites (Extended Search)

silica optical Summary: measurements and the so-called radiation-induced attenuation (RIA) measured in dBm. TSL measurements have been... measurements. Connections between...

211

E-Print Network 3.0 - attenuated recombinant vaccine Sample Search...  

NLE Websites -- All DOE Office Websites (Extended Search)

include subunit vaccines (9), naked DNA vaccines (10,11), and attenuated mycobacte- ria, including... of New Tuberculosis Vaccines 12;12. Horwitz MA, Harth G, Dillon BJ,...

212

E-Print Network 3.0 - attenuates collagen antibody-induced Sample...  

NLE Websites -- All DOE Office Websites (Extended Search)

Printed in the U.S.A. Iq90 Pergamon Press pie Summary: ultrasonic speed and attenuation coefficient were directly correlated with tissue collagen concentration... relationships...

213

Generation of first hard X-ray pulse at Tsinghua Thomson Scattering X-ray Source  

SciTech Connect

Tsinghua Thomson Scattering X-ray Source (TTX) is the first-of-its-kind dedicated hard X-ray source in China based on the Thomson scattering between a terawatt ultrashort laser and relativistic electron beams. In this paper, we report the experimental generation and characterization of the first hard X-ray pulses (51.7 keV) via head-on collision of an 800 nm laser and 46.7 MeV electron beams. The measured yield is 1.0 Multiplication-Sign 10{sup 6} per pulse with an electron bunch charge of 200 pC and laser pulse energy of 300 mJ. The angular intensity distribution and energy spectra of the X-ray pulse are measured with an electron-multiplying charge-coupled device using a CsI scintillator and silicon attenuators. These measurements agree well with theoretical and simulation predictions. An imaging test using the X-ray pulse at the TTX is also presented.

Du Yingchao; Yan Lixin; Hua Jianfei; Du Qiang; Zhang Zhen; Li Renkai; Qian Houjun; Huang Wenhui; Chen Huaibi; Tang Chuanxiang [Accelerator Laboratory, Department of Engineering Physics, Tsinghua University, Beijing 100084 (China); Key Laboratory of Particle and Radiation Imaging, Tsinghua University, Ministry of Education, Beijing 100084 (China); Key Laboratory of High Energy Radiation Imaging Fundamental Science for National Defense, Tsinghua University, Beijing 100084 (China)

2013-05-15T23:59:59.000Z

214

Gamma Ray Bursts  

E-Print Network (OSTI)

Olson. “Observations of gamma-ray bursts of cosmic origin. ”E. Lingenfelter. “Gamma-ray bursts. ” Annual Review of652-654. Waxman, Eli. “Gamma-ray-burst afterglow: supporting

Stahl, Bennett

2014-01-01T23:59:59.000Z

215

Gamma ray bursts, cosmic ray origin, and the unidentified EGRET sources  

Science Journals Connector (OSTI)

Statistical arguments show that the volume- and time-averaged kinetic power of GRBs and fireball transients (FTs) into an L* galaxy like the Milky Way is at the level of 10 40 ? ergs?s ?1 . This number though with wide uncertainties related to the internal or external shock efficiency is sufficient to power hadronic cosmic rays observed locally. The release of energy by the high-mass progenitor stars of GRBs and FTs is sufficient to power the ultrahigh energy cosmic rays as already shown by Waxman and Vietri in 1995. It is sufficient to power the cosmic rays above the knee of the cosmic-ray spectrum. Indeed all hadronic cosmic rays could originate from the high-mass (?100? M ? ) stars that collapse to black holes in the process forming GRBs and FTs. This source class represents a new solution to the problem of cosmic-ray origin. The ?10 4 –10 7 black holes made by these stars could make their presence known by radiating as they accrete from the ISM by microlensing background radiations and by forming luminous binary systems. Some unidentified EGRET sources could be isolated black holes that accrete from the ISM. Better imaging and sensitivity with GLAST and TeV observatories will test this model for the unidentified ?-ray sources and this theory for cosmic-ray origin.

Charles D. Dermer

2001-01-01T23:59:59.000Z

216

Mycophenolate mofetil attenuates pulmonary arterial hypertension in rats  

SciTech Connect

Pulmonary arterial hypertension (PAH) is characterized by abnormal proliferation of smooth muscle cells (SMCs), leading to occlusion of pulmonary arterioles, right ventricular (RV) hypertrophy, and death. We investigated whether mycophenolate mofetil (MMF), a potent immunosuppresssant, prevents the development of monocrotaline (MCT)-induced PAH in rats. MMF effectively decreased RV systolic pressure and RV hypertrophy, and reduced the medial thickness of pulmonary arteries. MMF significantly inhibited the number of proliferating cell nuclear antigen (PCNA)-positive cells, infiltration of macrophages, and expression of P-selectin and interleukin-6 on the endothelium of pulmonary arteries. The infiltration of T cells and mast cells was not affected by MMF. In vitro experiments revealed that mycophenolic acid (MPA), an active metabolite of MMF, dose-dependently inhibited proliferation of human pulmonary arterial SMCs. MMF attenuated the development of PAH through its anti-inflammatory and anti-proliferative properties. These findings provide new insight into the potential role of immunosuppressants in the treatment of PAH.

Suzuki, Chihiro [Division of Cardiovascular Sciences, Department of Organ Regeneration, Shinshu University Graduate School of Medicine, Matsumoto (Japan); Takahashi, Masafumi [Division of Cardiovascular Sciences, Department of Organ Regeneration, Shinshu University Graduate School of Medicine, Matsumoto (Japan)]. E-mail: masafumi@sch.md.shinshu-u.ac.jp; Morimoto, Hajime [Division of Cardiovascular Sciences, Department of Organ Regeneration, Shinshu University Graduate School of Medicine, Matsumoto (Japan); Izawa, Atsushi [Division of Cardiovascular Sciences, Department of Organ Regeneration, Shinshu University Graduate School of Medicine, Matsumoto (Japan); Ise, Hirohiko [Division of Cardiovascular Sciences, Department of Organ Regeneration, Shinshu University Graduate School of Medicine, Matsumoto (Japan); Hongo, Minoru [Department of Cardiovascular Medicine, Shinshu University School of Health Sciences, Matsumoto (Japan); Hoshikawa, Yasushi [Department of Thoracic Surgery, Institute of Development, Aging and Cancer, Tohoku University, Sendai (Japan); Ito, Takayuki [Department of Cardiovascular Medicine, Jichi Medical School, Tochigi (Japan); Miyashita, Hiroshi [Department of Cardiovascular Medicine, Jichi Medical School, Tochigi (Japan); Kobayashi, Eiji [Division of Organ Replacement Research, Jichi Medical School, Tochigi (Japan); Shimada, Kazuyuki [Department of Cardiovascular Medicine, Jichi Medical School, Tochigi (Japan); Ikeda, Uichi [Division of Cardiovascular Sciences, Department of Organ Regeneration, Shinshu University Graduate School of Medicine, Matsumoto (Japan)

2006-10-20T23:59:59.000Z

217

Memory effects in attenuation and amplification quantum processes  

E-Print Network (OSTI)

With increasing communication rates via quantum channels, memory effects become unavoidable whenever the use rate of the channel is comparable to the typical relaxation time of the channel environment. We introduce a model of a bosonic memory channel, describing correlated noise effects in quantum-optical processes via attenuating or amplifying media. To study such a channel model, we make use of a proper set of collective field variables, which allows us to unravel the memory effects, mapping the n-fold concatenation of the memory channel to a unitarily equivalent, direct product of n single-mode bosonic channels. We hence estimate the channel capacities by relying on known results for the memoryless setting. Our findings show that the model is characterized by two different regimes, in which the cross correlations induced by the noise among different channel uses are either exponentially enhanced or exponentially reduced.

Cosmo Lupo; Vittorio Giovannetti; Stefano Mancini

2010-05-17T23:59:59.000Z

218

Mass Spectrometer: Orbitrap | EMSL  

NLE Websites -- All DOE Office Websites (Extended Search)

Software (ISIS): A Machine Learning Approach to Tandem Mass Spectral Identification of Lipids. Liquid chromatography-mass spectrometry-based metabolomics has gained importance...

219

Mass Spectrometry | EMSL  

NLE Websites -- All DOE Office Websites (Extended Search)

and Microfabrication Mass Spectrometry Microscopy Molecular Science Computing NMR and EPR Spectroscopy and Diffraction Subsurface Flow and Transport Mass Spectrometry Systems...

220

Acoustic attenuation due to transformation twins in CaCl2: Analogue behaviour for stishovite  

E-Print Network (OSTI)

Acoustic attenuation due to transformation twins in CaCl2: Analogue behaviour for stishovite: Pseudoproper ferroelastic phase transition Ferroelastic twin walls Stishovite CaCl2 Acoustic attenuation a b s t r a c t CaCl2 undergoes a tetragonal (P42/mnm) to orthorhombic (Pnnm) transition as a function

Cambridge, University of

Note: This page contains sample records for the topic "ray mass attenuation" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


221

Seismic-frequency attenuation and moduli estimates using a fiber-optic strainmeter Ludmila Adam 1  

E-Print Network (OSTI)

Seismic-frequency attenuation and moduli estimates using a fiber-optic strainmeter Ludmila Adam 1 Summary We have developed a fiber-optic strainmeter to estimate velocities and attenuation at seismic only part of the core sample, the fiber-optic strainmeter would analyze the rock sample response

222

Conservative constraints on dark matter annihilation into gamma rays  

SciTech Connect

Using gamma-ray data from observations of the Milky Way, Andromeda (M31), and the cosmic background, we calculate conservative upper limits on the dark matter self-annihilation cross section to monoenergetic gamma rays, <{sigma}{sub A}v>{sub {gamma}}{sub {gamma}}, over a wide range of dark matter masses. (In fact, over most of this range, our results are unchanged if one considers just the branching ratio to gamma rays with energies within a factor of a few of the endpoint at the dark matter mass.) If the final-state branching ratio to gamma rays, Br({gamma}{gamma}), were known, then <{sigma}{sub A}v>{sub {gamma}}{sub {gamma}}/Br({gamma}{gamma}) would define an upper limit on the total cross section; we conservatively assume Br({gamma}{gamma}) > or approx. 10{sup -4}. An upper limit on the total cross section can also be derived by considering the appearance rates of any standard model particles; in practice, this limit is defined by neutrinos, which are the least detectable. For intermediate dark matter masses, gamma-ray-based and neutrino-based upper limits on the total cross section are comparable, while the gamma-ray limit is stronger for small masses and the neutrino limit is stronger for large masses. We comment on how these results depend on the assumptions about astrophysical inputs and annihilation final states, and how GLAST and other gamma-ray experiments can improve upon them.

Mack, Gregory D.; Yueksel, Hasan [Department of Physics, Ohio State University, Columbus, Ohio 43210 (United States); Center for Cosmology and Astro-Particle Physics, Ohio State University, Columbus, Ohio 43210 (United States); Jacques, Thomas D.; Bell, Nicole F. [School of Physics, The University of Melbourne, Victoria 3010 (Australia); Beacom, John F. [Department of Physics, Ohio State University, Columbus, Ohio 43210 (United States); Center for Cosmology and Astro-Particle Physics, Ohio State University, Columbus, Ohio 43210 (United States); Department of Astronomy, Ohio State University, Columbus, Ohio 43210 (United States)

2008-09-15T23:59:59.000Z

223

Modification of the TASMIP x-ray spectral model for the simulation of microfocus x-ray sources  

SciTech Connect

Purpose: The availability of accurate and simple models for the estimation of x-ray spectra is of great importance for system simulation, optimization, or inclusion of photon energy information into data processing. There is a variety of publicly available tools for estimation of x-ray spectra in radiology and mammography. However, most of these models cannot be used directly for modeling microfocus x-ray sources due to differences in inherent filtration, energy range and/or anode material. For this reason the authors propose in this work a new model for the simulation of microfocus spectra based on existing models for mammography and radiology, modified to compensate for the effects of inherent filtration and energy range. Methods: The authors used the radiology and mammography versions of an existing empirical model [tungsten anode spectral model interpolating polynomials (TASMIP)] as the basis of the microfocus model. First, the authors estimated the inherent filtration included in the radiology model by comparing the shape of the spectra with spectra from the mammography model. Afterwards, the authors built a unified spectra dataset by combining both models and, finally, they estimated the parameters of the new version of TASMIP for microfocus sources by calibrating against experimental exposure data from a microfocus x-ray source. The model was validated by comparing estimated and experimental exposure and attenuation data for different attenuating materials and x-ray beam peak energy values, using two different x-ray tubes. Results: Inherent filtration for the radiology spectra from TASMIP was found to be equivalent to 1.68 mm Al, as compared to spectra obtained from the mammography model. To match the experimentally measured exposure data the combined dataset required to apply a negative filtration of about 0.21 mm Al and an anode roughness of 0.003 mm W. The validation of the model against real acquired data showed errors in exposure and attenuation in line with those reported for other models for radiology or mammography. Conclusions: A new version of the TASMIP model for the estimation of x-ray spectra in microfocus x-ray sources has been developed and validated experimentally. Similarly to other versions of TASMIP, the estimation of spectra is very simple, involving only the evaluation of polynomial expressions.

Sisniega, A.; Vaquero, J. J., E-mail: juanjose.vaquero@uc3m.es [Departamento de Bioingeniería e Ingeniería Aeroespacial, Universidad Carlos III de Madrid, Madrid ES28911 (Spain); Instituto de Investigación Sanitaria Gregorio Marañón, Madrid ES28007 (Spain); Desco, M. [Departamento de Bioingeniería e Ingeniería Aeroespacial, Universidad Carlos III de Madrid, Madrid ES28911 (Spain) [Departamento de Bioingeniería e Ingeniería Aeroespacial, Universidad Carlos III de Madrid, Madrid ES28911 (Spain); Instituto de Investigación Sanitaria Gregorio Marañón, Madrid ES28007 (Spain); Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), Madrid ES28029 (Spain)

2014-01-15T23:59:59.000Z

224

Cosmic-ray driven winds  

E-Print Network (OSTI)

The theory of Galactic Winds, driven by the cosmic-ray pressure gradient, is reviewed both on the magnetohydrodynamic and on the kinetic level. In this picture the magnetic field of the Galaxy above the dense gas disk is assumed to have a flux tube geometry, the flux tubes rising locally perpendicular out of the disk to become radially directed at large distances, with the cosmic-ray sources located deep within the Galactic disk. At least above the gas disk, the magnetic fluctuations which resonantly scatter the cosmic rays are selfconsistently excited as Alf{`e}n waves by the escaping cosmic rays. The fluctuation amplitudes remain finite through nonlinear wave dissipation. The spatially increasing speed of the resulting outflow results in a diffusion-convection boundary whose position depends on particle momentum. It replaces the escape boundary of static diffusion models. New effects like overall Galactic mass and angular momentum loss as well as gas heating beyond the disk appear. Also particle re-accelera...

Völk, Heinrich J

2014-01-01T23:59:59.000Z

225

Gamma–ray bursts  

Science Journals Connector (OSTI)

...R. Priest and N. O. Weiss Gamma-ray bursts Martin J. Rees Institute of...Road, Cambridge CB3 0HA, UK Gamma-ray bursts, an enigma for more than 25...gamma-rays|neutron stars| Gamma-ray bursts By Martin J. Rees Institute...

2000-01-01T23:59:59.000Z

226

Applying x-ray digital imaging to the verification of cadmium in fuel-storage components  

SciTech Connect

The High Flux Isotope Reactor utilizes large underwater fuel-storage arrays to stage irradiated fuel before it is shipped from the facility. Cadmium is required as a thermal neutron absorber in these fuel-storage arrays to produce an acceptable margin of nuclear subcriticality during both normal and off-normal operating conditions. Due to incomplete documentation from the time of their fabrication, the presence of cadmium within two stainless-steel parts of fuel-storage arrays must be experimentally verified before they are reused in new fuel-storage arrays. A cadmium-verification program has been developed in association with the Waste Examination and Assay Facility located at the Oak Ridge national Laboratory to nondestructively examine these older shroud assemblies. The program includes the following elements (1) x-ray analog imaging, (2) x-ray digital imaging, (3) prompt-gamma-ray spectroscopy measurements, and (4) neutron-transmission measurements. X-ray digital imaging utilizes an analog-to-digital convertor to record attenuated x-ray intensities observed on a fluorescent detector by a video camera. These x-ray intensities are utilized in expressions for cadmium thickness based upon x-ray attenuation theory.

Dabbs, R.D.; Cook, D.H.

1997-03-01T23:59:59.000Z

227

Gamma ray burst positrons  

Science Journals Connector (OSTI)

The international network of gamma ray burst detectors has provided redundant localizations for six gamma ray bursts with accuracies in the arcminute range. Catalog radio soft X?ray and optical searches have been performed for some of these events. The results of these searches are reviewed. Although radio X?ray and optical candidates are found in the error boxes no clear association between gamma ray bursts and other forms of emission has emerged to date. Optical radio searches are continuing.

K. Hurley

1982-01-01T23:59:59.000Z

228

Gamma ray generator  

DOE Patents (OSTI)

An embodiment of a gamma ray generator includes a neutron generator and a moderator. The moderator is coupled to the neutron generator. The moderator includes a neutron capture material. In operation, the neutron generator produces neutrons and the neutron capture material captures at least some of the neutrons to produces gamma rays. An application of the gamma ray generator is as a source of gamma rays for calibration of gamma ray detectors.

Firestone, Richard B; Reijonen, Jani

2014-05-27T23:59:59.000Z

229

Mass spectrometric immunoassay  

DOE Patents (OSTI)

Rapid mass spectrometric immunoassay methods for detecting and/or quantifying antibody and antigen analytes utilizing affinity capture to isolate the analytes and internal reference species (for quantification) followed by mass spectrometric analysis of the isolated analyte/internal reference species. Quantification is obtained by normalizing and calibrating obtained mass spectrum against the mass spectrum obtained for an antibody/antigen of known concentration.

Nelson, Randall W; Williams, Peter; Krone, Jennifer Reeve

2013-07-16T23:59:59.000Z

230

Mass spectrometric immunoassay  

DOE Patents (OSTI)

Rapid mass spectrometric immunoassay methods for detecting and/or quantifying antibody and antigen analytes utilizing affinity capture to isolate the analytes and internal reference species (for quantification) followed by mass spectrometric analysis of the isolated analyte/internal reference species. Quantification is obtained by normalizing and calibrating obtained mass spectrum against the mass spectrum obtained for an antibody/antigen of known concentration.

Nelson, Randall W (Phoenix, AZ); Williams, Peter (Phoenix, AZ); Krone, Jennifer Reeve (Granbury, TX)

2007-12-04T23:59:59.000Z

231

Thermal neutron capture gamma-rays  

SciTech Connect

The energy and intensity of gamma rays as seen in thermal neutron capture are presented. Only those (n,..cap alpha..), E = thermal, reactions for which the residual nucleus mass number is greater than or equal to 45 are included. These correspond to evaluations published in Nuclear Data Sheets. The publication source data are contained in the Evaluated Nuclear Structure Data File (ENSDF). The data presented here do not involve any additional evaluation. Appendix I lists all the residual nuclides for which the data are included here. Appendix II gives a cumulated index to A-chain evaluations including the year of publication. The capture gamma ray data are given in two tables - the Table 1 is the list of all gamma rays seen in (n,..gamma..) reaction given in the order of increasing energy; the Table II lists the gamma rays according to the nuclide.

Tuli, J.K.

1983-01-01T23:59:59.000Z

232

Gravitational waves and gamma-ray bursts  

E-Print Network (OSTI)

Gamma-Ray Bursts are likely associated with a catastrophic energy release in stellar mass objects. Electromagnetic observations provide important, but indirect information on the progenitor. On the other hand, gravitational waves emitted from the central source, carry direct information on its nature. In this context, I give an overview of the multi-messenger study of gamma-ray bursts that can be carried out by using electromagnetic and gravitational wave observations. I also underline the importance of joint electromagnetic and gravitational wave searches, in the absence of a gamma-ray trigger. Finally, I discuss how multi-messenger observations may probe alternative gamma-ray burst progenitor models, such as the magnetar scenario.

Alessandra Corsi; for the LIGO Scientific Collaboration; for the Virgo Collaboration

2012-05-11T23:59:59.000Z

233

Population synthesis for symbiotic X-ray binaries  

Science Journals Connector (OSTI)

......X-ray luminosities (mass-accretion rates...models with a low wind velocity (v w = 1/2v esc...Figure 6 Grey-scale maps of the distributions...period P s versus mass-accretion rate...greatly depends on the wind velocity. NSs in 4U 1954......

G.-L. Lü; C.-H. Zhu; K. A. Postnov; L. R. Yungelson; A. G. Kuranov; N. Wang

2012-08-11T23:59:59.000Z

234

A Comparison of Intermediate Mass Black Hole Candidate ULXs and Stellar-Mass Black Holes  

E-Print Network (OSTI)

Cool thermal emission components have recently been revealed in the X-ray spectra of a small number of ultra-luminous X-ray (ULX) sources with L_X > 1 E+40 erg/s in nearby galaxies. These components can be well fitted with accretion disk models, with temperatures approximately 5-10 times lower than disk temperatures measured in stellar-mass Galactic black holes when observed in their brightest states. Because disk temperature is expected to fall with increasing black hole mass, and because the X-ray luminosity of these sources exceeds the Eddington limit for 10 Msun black holes (L_Edd = 1.3 E+39 erg/s), these sources are extremely promising intermediate-mass black hole candidates (IMBHCs). In this Letter, we directly compare the inferred disk temperatures and luminosities of these ULXs, with the disk temperatures and luminosities of a number of Galactic black holes. The sample of stellar-mass black holes was selected to include different orbital periods, companion types, inclinations, and column densities. These ULXs and stellar-mass black holes occupy distinct regions of a L_X -- kT diagram, suggesting these ULXs may harbor IMBHs. We briefly discuss the important strengths and weaknesses of this interpretation.

J. M. Miller; A. C. Fabian; M. C. Miller

2004-06-29T23:59:59.000Z

235

Total Absorption Gamma-ray Spectrometer (TAGS) Intensity Distributions from INL's Gamma-Ray Spectrometry Center  

DOE Data Explorer (OSTI)

A 252Cf fission-product source and the INL on-line isotope separator were used to supply isotope-separated fission-product nuclides to a total absorption -ray spectrometer. This spectrometer consisted of a large (25.4-cm diameter x 30.5-cm long) NaI(Tl) detector with a 20.3-cm deep axial well in which is placed a 300-mm2 x 1.0-mm Si detector. The spectra from the NaI(Tl) detector are collected both in the singles mode and in coincidence with the B-events detected in the Si detector. Ideally, this detector would sum all the energy of the B- rays in each cascade following the population of daughter level by B- decay, so that the event could be directly associated with a particular daughter level. However, there are losses of energy from attenuation of the rays before they reach the detector, transmission of rays through the detector, escape of secondary photons from Compton scattering, escape of rays through the detector well, internal conversion, etc., and the measured spectra are thus more complicated than the ideal case and the analysis is more complex. Analysis methods have been developed to simulate all of these processes and thus provide a direct measure of the B- intensity distribution as a function of the excitation energy in the daughter nucleus. These data yield more accurate information on the B- distribution than conventional decay-scheme studies for complex decay schemes with large decay energies, because in the latter there are generally many unobserved and observed but unplaced rays. The TAGS data have been analyzed and published [R. E. Greenwood et al., Nucl Instr. and metho. A390(1997)] for 40 fission product-nuclides to determine the B- intensity distributions. [Copied from the TAGS page at http://www.inl.gov/gammaray/spectrometry/tags.shtml]. Those values are listed on this page for quick reference.

Greenwood, R.E.

236

X-ray Fluorescence Measurements of Manganese in Petroglyphs and Graffiti in the Bluff, Utah Area  

E-Print Network (OSTI)

X-ray Fluorescence Measurements of Manganese in Petroglyphs and Graffiti in the Bluff, Utah Area the age of rock art using Mn levels, Lytle (2008). In this work we use x-ray fluorescence (XRF) to measure of methods including atomic mass spectroscopy (AMS) measurements of 14 C, Particle-induced X-ray Excitation

237

Ultra High Energy Cosmic Rays: origin and propagation  

E-Print Network (OSTI)

We discuss the basic difficulties in understanding the origin of the highest energy particles in the Universe - the ultrahigh energy cosmic rays (UHECR). It is difficult to imagine the sources they are accelerated in. Because of the strong attenuation of UHECR on their propagation from the sources to us these sources should be at cosmologically short distance from us but are currently not identified. We also give information of the most recent experimental results including the ones reported at this conference and compare them to models of the UHECR origin.

Todor Stanev

2007-11-14T23:59:59.000Z

238

Ultrasonic attenuation and volume viscosity in liquid argon, nitrogen and helium  

E-Print Network (OSTI)

. Ultrasonic attenuation in liquid nitrogen at 49. 45 Hc/sec ll. Dersity dependence of the volume viscosity in l. iquid nitrogen 12. Density dependence of Qv/&(S in liquid nitrogen 40 13. Ultrasonic attenuation in liquid helium at 4. 20 K 43 14. Ultrasonic... attenuation in liquid helium at 3. 69"K 44 15. Qv in liquid argon and nitrogen as a function of reduced density 51 LIST OF TABLES 1. Data and results for the calculation of volume viscosity in liquid argon 2. Data and results for the calculation of volume...

Singer, James Robert

2012-06-07T23:59:59.000Z

239

24. Cosmic rays 1 24. COSMIC RAYS  

E-Print Network (OSTI)

electrons, protons and helium, as well as carbon, oxygen, iron, and other nuclei synthesized in stars) and the intensity of the cosmic rays with energies below about 10 GeV. In addition, the lower-energy cosmic rays the intensity of any component of the cosmic radiation in the GeV range depends both on the location and time

240

26. Cosmic rays 1 26. COSMIC RAYS  

E-Print Network (OSTI)

electrons, protons and helium, as well as carbon, oxygen, iron, and other nuclei synthesized in stars) and the intensity of the cosmic rays with energies below about 10 GeV. In addition, the lower-energy cosmic rays the intensity of any component of the cosmic radiation in the GeV range depends both on the location and time

Note: This page contains sample records for the topic "ray mass attenuation" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


241

Bounds on relicneutrino masses in the Z-burst model  

Science Journals Connector (OSTI)

Neutrinosfrom far-away sources annihilating at the Z-resonance on relic neutrinos maygive origin to the extreme-energy cosmic rays (EECR). If “Z-bursts” are responsiblefor the EECR events, then we show that the nonobservation of cosmic ray eventsat energies above 2×1020??eV bythe AGASA Collaboration implies a lower bound ?0.3??eV onthe relic neutrino mass. Since this mass exceeds the mass-squared differencesinferred from oscillation physics, the bound in fact applies to all threeneutrino masses. Together with the upper bound provided by comparisons ofthe CMB anisotropy with large-scale structure, this bound leaves only a smallinterval for neutrino masses around 0.3 eV, if Z-burstsare to explain the existing EECR events.

Graciela Gelmini; Gabriele Varieschi; Thomas Weiler

2004-12-03T23:59:59.000Z

242

Polarization mesurements of gamma ray bursts and axion like particles  

E-Print Network (OSTI)

A polarized gamma ray emission spread over a sufficiently wide energy band from a strongly magnetized astrophysical object like gamma ray bursts (GRBs) offers an opportunity to test the hypothesis of axion like particles (ALPs). Based on evidences of polarized gamma ray emission detected in several gamma ray bursts we estimated the level of ALPs induced dichroism, which could take place in the magnetized fireball environment of a GRB. This allows to estimate the sensitivity of polarization measurements of GRBs to the ALP-photon coupling. This sensitivity $\\gag\\le 2.2\\cdot 10^{-11} {\\rm GeV^{-1}}$ calculated for the ALP mass $m_a=10^{-3}~{\\rm eV}$ and MeV energy spread of gamma ray emission is competitive with the sensitivity of CAST and becomes even stronger for lower ALPs masses.

Andre Rubbia; Alexander Sakharov

2008-09-03T23:59:59.000Z

243

HAWC ?-Ray Observatory  

NLE Websites -- All DOE Office Websites (Extended Search)

(HAWC) Gamma Ray Observatory formally began operations. HAWC is designed to study the origin of very high-energy cosmic rays and observe the most energetic objects in the known...

244

Oscillations During Thermonuclear X-ray Bursts  

E-Print Network (OSTI)

High amplitude, nearly coherent X-ray brightness oscillations during thermonuclear X-ray bursts were discovered with the Rossi X-ray Timing Explorer (RXTE) in early 1996. Spectral and timing evidence strongly supports the conclusion that these oscillations are caused by rotational modulation of the burst emission and that they reveal the spin frequency of neutron stars in low mass X-ray binaries, a long sought goal of X-ray astronomy. Studies carried out over the past year have led to the discovery of burst oscillations in four new sources, bringing to ten the number with confirmed burst oscillations. I review the status of our knowledge of these oscillations and indicate how they can be used to probe the physics of neutron stars. For a few burst oscillation sources it has been proposed that the strongest and most ubiquitous frequency is actually the first overtone of the spin frequency and hence that two nearly antipodal hot spots are present on the neutron star. This inference has important implications for both the physics of thermonuclear burning as well as the mass - radius relation for neutron stars, so its confirmation is crucial. I discuss recent attempts to confirm this hypothesis for 4U 1636-53, the source for which a signal at the putative fundamental (290 Hz) has been claimed.

Tod E. Strohmayer

2001-01-12T23:59:59.000Z

245

Frequency-dependent attenuation and elasticity in unconsolidated earth materials: effect of damping  

E-Print Network (OSTI)

We use the Discrete Element Method (DEM) to understand the underlying attenuation mechanism in granular media, with special applicability to the measurements of the so-called effective mass developed earlier. We consider that the particles interact via Hertz-Mindlin elastic contact forces and that the damping is describable as a force proportional to the velocity difference of contacting grains. We determine the behavior of the complex-valued normal mode frequencies using 1) DEM, 2) direct diagonalization of the relevant matrix, and 3) a numerical search for the zeros of the relevant determinant. All three methods are in strong agreement with each other. The real and the imaginary parts of each normal mode frequency characterize the elastic and the dissipative properties, respectively, of the granular medium. We demonstrate that, as the interparticle damping, $\\xi$, increases, the normal modes exhibit nearly circular trajectories in the complex frequency plane and that for a given value of $\\xi$ they all lie on or near a circle of radius $R$ centered on the point $-iR$ in the complex plane, where $R\\propto 1/\\xi$. We show that each normal mode becomes critically damped at a value of the damping parameter $\\xi \\approx 1/\\omega_n^0$, where $\\omega_n^0$ is the (real-valued) frequency when there is no damping. The strong indication is that these conclusions carry over to the properties of real granular media whose dissipation is dominated by the relative motion of contacting grains. For example, compressional or shear waves in unconsolidated dry sediments can be expected to become overdamped beyond a critical frequency, depending upon the strength of the intergranular damping constant.

Yanqing Hu; Hernán A. Makse; John J. Valenza; David L. Johnson

2014-10-20T23:59:59.000Z

246

EMSL - Mass Spectrometry  

NLE Websites -- All DOE Office Websites (Extended Search)

mass-spectrometry Proteomics Capabilities High resolution and mass accuracy Fourier-transform ion cyclotron resonance (FT-ICR) spectrometers, from 6 Tesla (T) to 15T and 21T in...

247

mass communication advertising &  

E-Print Network (OSTI)

mass communication advertising & public relations introduction. Graduate programs in the Department of Mass Communication, Advertising, and Public Relations provide an entry to a wide spectrum of careers the opportunity to create content, campaigns, strategy, and research in public relations, advertising

Finzi, Adrien

248

Ray J. Corey- Biography  

Energy.gov (U.S. Department of Energy (DOE))

Ray Corey currently serves as the Assistance Manager for Safety and Environment at the DOE Richland Operations office (RL).

249

NEUTRINO-COOLED ACCRETION MODEL WITH MAGNETIC COUPLING FOR X-RAY FLARES IN GAMMA-RAY BURSTS  

SciTech Connect

The neutrino-cooled accretion disk, which was proposed to work as the central engine of gamma-ray bursts, encounters difficulty in interpreting the X-ray flares after the prompt gamma-ray emission. In this paper, the magnetic coupling (MC) between the inner disk and the central black hole (BH) is taken into consideration. For mass accretion rates around 0.001 {approx} 0.1 M{sub Sun} s{sup -1}, our results show that the luminosity of neutrino annihilation can be significantly enhanced due to the coupling effects. As a consequence, after the gamma-ray emission, a remnant disk with mass M{sub disk} {approx}< 0.5 M{sub Sun} may power most of the observed X-ray flares with the rest frame duration less than 100 s. In addition, a comparison between the MC process and the Blandford-Znajek mechanism is shown on the extraction of BH rotational energy.

Luo Yang; Gu Weimin; Liu Tong; Lu Jufu, E-mail: guwm@xmu.edu.cn [Department of Astronomy and Institute of Theoretical Physics and Astrophysics, Xiamen University, Xiamen, Fujian 361005 (China)

2013-08-20T23:59:59.000Z

250

Natural and Enhanced Attenuation of Soil and Groundwater at the Monument  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Natural and Enhanced Attenuation of Soil and Groundwater at the Natural and Enhanced Attenuation of Soil and Groundwater at the Monument Valley, Arizona, DOE Legacy Waste Site Natural and Enhanced Attenuation of Soil and Groundwater at the Monument Valley, Arizona, DOE Legacy Waste Site Paper presented at the Waste Management 2010 Conference. March 7 through March 10, 2010, Phoenix, Arizona. W.J.Waugh, D.E. Miller, S.A. Morris, L.R. Sheader, E.P. Glenn, D. Moore, K.C. Carroll, L. Benally, M. Roanhorse, R.P. Bush Natural and Enhanced Attenuation of Soil and Groundwater at the Monument Valley, Arizona, DOE Legacy Waste Site More Documents & Publications EA-1313: Final Environmental Assessment Applied Science and Technology Task Order Fiscal Year 2009 Year-End Summary Report Applied Science and Technology Task Order Fiscal Year 2008 Year-End Summary

251

Design of compliant mechanisms for attenuation of unidirectional vibrations in rotational systems  

E-Print Network (OSTI)

The purpose of this research was to generate the knowledge required to design compliant mechanisms that (1) attenuate undesired small-motion angular vibrations in rotational power transmission systems and (2) preserve the ...

Szczesny, Spencer E., 1981-

2005-01-01T23:59:59.000Z

252

E-Print Network 3.0 - attenuates bone cancer Sample Search Results  

NLE Websites -- All DOE Office Websites (Extended Search)

cancer Search Powered by Explorit Topic List Advanced Search Sample search results for: attenuates bone cancer Page: << < 1 2 3 4 5 > >> 1 Questions and Answers About Bone Cancer...

253

Frontiers in Assessing the Role of Chemical Speciation and Natural Attenuation on the Bioavailability  

E-Print Network (OSTI)

1 Frontiers in Assessing the Role of Chemical Speciation and Natural Attenuation components. Applications of these techniques to assess metal and organic chemical sorption/release, natural widely employed to provide an indirect assessment ofchemical speciation and association ofcontaminants

Sparks, Donald L.

254

The effect of hydrogen on ultrasonic attenuation and Velocity measurements in titanium  

Science Journals Connector (OSTI)

Ultrasonic attenuation and velocity were measured in commercially pure titanium over an ultrasonic frequency range from 10 to 50 mc/s before and after heating in hydrogen. The two ultrasonic quantities changed by large amounts when the metal was heated in hydrogen at temperatures near 550°C. The main feature is that the attenuation decreased with the increasing hydrogen content. The changes induced by heating in hydrogen resulted mainly from the appearance of titaniumhydrogen phases although hydrogen in solution may also have had an effect. Similar treatment of the titanium in vacuum, oxygen, and nitrogen did not produce appreciable changes in attenuation, velocity, or microstructure. Unfortunately the use of attenuation measurement work at these frequencies is in early stages of development and no unique identification of the mechanisms involved can be given at present. As a consequence this paper is limited to discussion of the experimental observations and effects.

C.F Ying; R Truell

1954-01-01T23:59:59.000Z

255

E-Print Network 3.0 - attenuation physics Sample Search Results  

NLE Websites -- All DOE Office Websites (Extended Search)

physics Search Powered by Explorit Topic List Advanced Search Sample search results for: attenuation physics Page: << < 1 2 3 4 5 > >> 1 Physical modeling and analysis of P-wave...

256

E-Print Network 3.0 - attenuates brain edema Sample Search Results  

NLE Websites -- All DOE Office Websites (Extended Search)

brain edema Search Powered by Explorit Topic List Advanced Search Sample search results for: attenuates brain edema Page: << < 1 2 3 4 5 > >> 1 Glucose-Derived Osmolytes and Energy...

257

E-Print Network 3.0 - attenuates angiotensin ii-induced Sample...  

NLE Websites -- All DOE Office Websites (Extended Search)

and without ANG II. Expression of ARKct did not attenuate ANG II-induced potentiation of ISO-stimulated c... of PKC by GF109203X (10 M) failed to inhibit the ANG II-induced...

258

E-Print Network 3.0 - attenuating directional polarization Sample...  

NLE Websites -- All DOE Office Websites (Extended Search)

is directly observed via scattered light. The attenuation length of surface plasmons in a broad wavelength... direction in Fig. 5) and on a shorter distance in the positive x...

259

Hydrogel-Encapsulated Soil: A Tool to Measure Contaminant Attenuation In Situ  

Science Journals Connector (OSTI)

To illustrate how potential remedial techniques can be compared to natural attenuation, thermal stabilization of one soil increased the size of its long-term in situ retained fraction from 50% to 88% of the total uranium and increased the half-life of that long-term retained fraction from 990 to 40000 days. ... Although natural attenuation is being increasingly selected as a preferred alternative for remediation of many hazardous waste sites, the Committee on Intrinsic Remediation of the National Research Council (2) has warned, “... that rigorous protocols are needed to ensure that natural attenuation potential is analyzed properly, and that natural attenuation should be accepted as a formal remedy for contamination only when the processes are documented to be working and are sustainable.” ... To establish the potential of the hydrogel-encapsulation technique as a valid tool to study contaminant interactions with groundwater in situ, our investigation focused on several proof-of-principle objectives using uranium as a model contaminant. ...

Brian P. Spalding; Scott C. Brooks; David B. Watson

2010-03-15T23:59:59.000Z

260

Attenuation of low?frequency sound in the Northeast Pacific Ocean  

Science Journals Connector (OSTI)

Long?range propagation losses were measured at frequencies from 0.025 to 0.8 kHz to the north and south of a receiver at 46?°N 143°30?W in the Northeast Pacific. To the south of the station the attenuation losses experienced a pronounced minimum near 50 Hz and approached the one?half Thorp value at 0.8 kHz. An examination of the behavior of the attenuation coefficient as a function of range indicated that a range of at least 700 km would be required to make meaningful measurements of attenuation in this area. To the north of the receiving station focusing of the sound due to a rapidly shallowing sound channel prevented reliable measurement of the attenuation coefficient at any range.

R. K. Chow; R. G. Turner

1982-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "ray mass attenuation" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


261

E-Print Network 3.0 - attenuates long-term potentiation Sample...  

NLE Websites -- All DOE Office Websites (Extended Search)

search results for: attenuates long-term potentiation Page: << < 1 2 3 4 5 > >> 1 Use of innovative technology for analysis of 54 VOCs in water: ITEX solution TOGOLA A., Girardeau...

262

E-Print Network 3.0 - agmatine attenuates nitric Sample Search...  

NLE Websites -- All DOE Office Websites (Extended Search)

attenuates nitric Page: << < 1 2 3 4 5 > >> 1 Learning and memory in agmatine-treated rats B.E. McKay*, W.E. Lado1 Summary: . Inhibition of mammalian nitric oxide synthases by...

263

Theory of acoustic attenuation, dispersion, and pulse propagation in unconsolidated granular materials including  

E-Print Network (OSTI)

Theory of acoustic attenuation, dispersion, and pulse propagation in unconsolidated granular of particles in contact with a new, rough-surface, random-packing model of mineral grains in unconsolidated

Buckingham, Michael

264

Attenuation-Based Remedies in the Subsurface Applied Field Research Initiative (ABRS AFRI)  

Energy.gov (U.S. Department of Energy (DOE))

Located at the Savannah River Site in Aiken, South Carolina, the Attenuation-Based Remedies in the Subsurface Applied Field Research Initiative (ABRS AFRI) was established to develop the tools,...

265

Nitrate occurrence and attenuation in the major aquifers of England and Wales  

Science Journals Connector (OSTI)

...Examination of the delta15N composition of infiltrating nitrate relative...L., Zech, W., The composition of dissolved organic matter...Migration and attenuation of agrochemical pollutants: insights from...The nitrogen isotope composition of groundwater nitrates from...

M.O. Rivett; J.W.N. Smith; S.R. Buss; P. Morgan

266

Anomalous shear wave attenuation in the shallow crust beneath the Coso  

Open Energy Info (EERE)

Anomalous shear wave attenuation in the shallow crust beneath the Coso Anomalous shear wave attenuation in the shallow crust beneath the Coso volcanic region, California Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: Anomalous shear wave attenuation in the shallow crust beneath the Coso volcanic region, California Details Activities (1) Areas (1) Regions (0) Abstract: We use seismograms of local earthquakes to image relative shear wave attenuation structure in the shallow crust beneath the region containing the Coso volcanic-geothermal area of eastern California. SV and P wave amplitudes were measured from vertical component seismograms of earthquakes that occurred in the Coso-southern Sierra Nevada region from July 1983 to 1985. Seismograms of 16 small earthquakes show SV amplitudes which are greatly diminished at some azimuths and takeoff angles,

267

Computers & Geosciences 29 (2003) 351359 A case against Kd-based transport models: natural attenuation  

E-Print Network (OSTI)

attenuation at a mill tailings site Chen Zhu* Department of Geology and Planetary Science, University)-based transport model. The study site is a contaminated groundwater aquifer underneath a uranium mill tailings

Polly, David

268

Elbow mass flow meter  

DOE Patents (OSTI)

Elbow mass flow meter. The present invention includes a combination of an elbow pressure drop generator and a shunt-type mass flow sensor for providing an output which gives the mass flow rate of a gas that is nearly independent of the density of the gas. For air, the output is also approximately independent of humidity.

McFarland, Andrew R. (College Station, TX); Rodgers, John C. (Santa Fe, NM); Ortiz, Carlos A. (Bryan, TX); Nelson, David C. (Santa Fe, NM)

1994-01-01T23:59:59.000Z

269

Cosmology with X-ray Cluster Baryons  

SciTech Connect

X-ray cluster measurements interpreted with a universal baryon/gas mass fraction can theoretically serve as a cosmological distance probe. We examine issues of cosmological sensitivity for current (e.g., Chandra X-ray Observatory, XMM-Newton) and next generation (e.g., Con-X, XEUS) observations, along with systematic uncertainties and biases. To give competitive next generation constraints on dark energy, we find that systematics will need to be controlled to better than 1percent and any evolution in f_gas (and other cluster gas properties) must be calibrated so the residual uncertainty is weaker than (1+z)0.03.

Linder, Eric V.

2007-04-10T23:59:59.000Z

270

Further measurements of low?frequency attenuation in the Southwest Pacific Ocean  

Science Journals Connector (OSTI)

Previously unpublished results from a 1978 acoustic propagation experiment in the Southwest Pacific Ocean to the east of New Zealand are combined with earlier data to produce measured values of the water column attenuation over the frequency range 32–1000 Hz. The attenuation values so obtained compare well with a modified Thorp formula having a boron relaxation term and a scattering term generally consistent with earlier estimates for the region.

R. N. Denham; K. M. Guthrie; D. G. Browning

1987-01-01T23:59:59.000Z

271

Gamma-ray Astronomy  

E-Print Network (OSTI)

The relevance of gamma-ray astronomy to the search for the origin of the galactic and, to a lesser extent, the ultra-high-energy cosmic rays has long been recognised. The current renaissance in the TeV gamma-ray field has resulted in a wealth of new data on galactic and extragalactic particle accelerators, and almost all the new results in this field were presented at the recent International Cosmic Ray Conference (ICRC). Here I summarise the 175 papers submitted on the topic of gamma-ray astronomy to the 30th ICRC in Merida, Mexico in July 2007.

Jim Hinton

2007-12-20T23:59:59.000Z

272

Fermi establishes classical novae as a distinct class of gamma-ray sources  

Science Journals Connector (OSTI)

...matter from a low-mass main-sequence stellar...compositions and masses of their white dwarf...processes linked to the mass ejection from thermonuclear...the circumstellar wind of the red giant companion, and...gamma}-ray counts maps of the four novae...and expansion velocities vej at early...

The Fermi-LAT Collaboration

2014-08-01T23:59:59.000Z

273

Attenuator design for organs at risk in total body irradiation using a translation technique  

SciTech Connect

Total body irradiation (TBI) is an efficient part of the treatment for malignant hematological diseases. Dynamic TBI techniques provide great advantages (e.g., dose homogeneity, patient comfort) while overcoming treatment room space restrictions. However, with dynamic techniques come additional organs at risk (OAR) protection challenges. In most dynamic TBI techniques, lead attenuators are used to diminish the dose received by the OARs. The purpose of this study was to characterize the dose deposition under various shapes of attenuators in static and dynamic treatments. This characterization allows for the development of a correction method to improve attenuator design in dynamic treatments. The dose deposition under attenuators at different depths in dynamic treatment was compared with the static situation based on two definitions: the coverage areas and the penumbra regions. The coverage area decreases with depth in dynamic treatment while it is stable for the static situation. The penumbra increases with depth in both treatment modes, but the increasing rate is higher in the dynamic situation. Since the attenuator coverage is deficient in the dynamic treatment mode, a correction method was developed to modify the attenuator design in order to improve the OAR protection. The correction method is divided in two steps. The first step is based on the use of elongation charts, which provide appropriate attenuator coverage and acceptable penumbra for a specific depth. The second point is a correction method for the thoracic inclination, which can introduce an orientation problem in both static and dynamic treatments. This two steps correction method is simple to use and personalized to each patient's anatomy. It can easily be adapted to any dynamic TBI techniques.

Lavallee, Marie-Claude; Aubin, Sylviane; Chretien, Mario; Larochelle, Marie; Beaulieu, Luc [Departement de Radio-Oncologie et Centre de Recherche en Cancerologie, CHUQ Pavillon L'Hotel-Dieu de Quebec, 11 Cote du Palais, Quebec, Quebec, G1R 2J6 (Canada) and Departement de Physique, de Genie Physique et d'Optique, Universite Laval, Quebec, Quebec, G1K 7P4 (Canada); Departement de Radio-Oncologie et Centre de Recherche en Cancerologie, CHUQ Pavillon L'Hotel-Dieu de Quebec, 11 Cote du Palais, Quebec, Quebec, G1R 2J6 (Canada); Departement de Radio-Oncologie et Centre de Recherche en Cancerologie, CHUQ, Pavillon L'Hotel-Dieu de Quebec, 11 Cote du Palais, Quebec, Quebec, G1R 2J6 (Canada) and Departement de Physique, de Genie Physique et d'Optique, Universite Laval, Quebec, Quebec, G1K 7P4 (Canada)

2008-05-15T23:59:59.000Z

274

Ultrasound guided fluorescence molecular tomography with improved quantification by an attenuation compensated born-normalization and in vivo preclinical study of cancer  

SciTech Connect

Ultrasound imaging, having the advantages of low-cost and non-invasiveness over MRI and X-ray CT, was reported by several studies as an adequate complement to fluorescence molecular tomography with the perspective of improving localization and quantification of fluorescent molecular targets in vivo. Based on the previous work, an improved dual-modality Fluorescence-Ultrasound imaging system was developed and then validated in imaging study with preclinical tumor model. Ultrasound imaging and a profilometer were used to obtain the anatomical prior information and 3D surface, separately, to precisely extract the tissue boundary on both sides of sample in order to achieve improved fluorescence reconstruction. Furthermore, a pattern-based fluorescence reconstruction on the detection side was incorporated to enable dimensional reduction of the dataset while keeping the useful information for reconstruction. Due to its putative role in the current imaging geometry and the chosen reconstruction technique, we developed an attenuation compensated Born-normalization method to reduce the attenuation effects and cancel off experimental factors when collecting quantitative fluorescence datasets over large area. Results of both simulation and phantom study demonstrated that fluorescent targets could be recovered accurately and quantitatively using this reconstruction mechanism. Finally, in vivo experiment confirms that the imaging system associated with the proposed image reconstruction approach was able to extract both functional and anatomical information, thereby improving quantification and localization of molecular targets.

Li, Baoqiang; Berti, Romain; Abran, Maxime; Lesage, Frédéric, E-mail: frederic.lesage@polymtl.ca [Institute of Biomedical Engineering, École Polytechnique de Montréal, Montreal, Quebec H3C 3A7 (Canada) [Institute of Biomedical Engineering, École Polytechnique de Montréal, Montreal, Quebec H3C 3A7 (Canada); Montreal Heart Institute, Montreal, Quebec H1T 1C8 (Canada)

2014-05-15T23:59:59.000Z

275

Nuclear Masses in Astrophysics  

E-Print Network (OSTI)

Among all nuclear ground-state properties, atomic masses are highly specific for each particular combination of N and Z and the data obtained apply to a variety of physics topics. One of the most crucial questions to be addressed in mass spectrometry of unstable radionuclides is the one of understanding the processes of element formation in the Universe. To this end, accurate atomic mass values of a large number of exotic nuclei participating in nucleosynthesis are among the key input data in large-scale reaction network calculations. In this paper, a review on the latest achievements in mass spectrometry for nuclear astrophysics is given.

Christine Weber; Klaus Blaum; Hendrik Schatz

2008-12-09T23:59:59.000Z

276

EMSL - Mass Spectrometer  

NLE Websites -- All DOE Office Websites (Extended Search)

mass-spectrometer en Physical Properties of Ambient and Laboratory-Generated Secondary Organic Aerosol. http:www.emsl.pnl.govemslwebpublicationsphysical-properties-ambient-and...

277

Parallel Seismic Ray Tracing  

E-Print Network (OSTI)

. . . . . . . . . . . . . . . . . . . . . 27 3.4.1 Rotated Take-Off Angle Mesh . . . . . . . . . . . . . . . . . . 28 3.4.2 Rotated Cubed Sphere Mesh . . . . . . . . . . . . . . . . . . . 29 3.4.3 Ray Tube Interpolation . . . . . . . . . . . . . . . . . . . . . . 30 3.5 Theoretical Model..., the ray parameters are defined as ?1 = ?(declination), ?2 = ?(azimuth), and ?3 = ?(travel-time). (b) Suppose we have a unit cube centered at the source point, then a ray can be traced from the source point through an evenly discretized point on the face...

Jain, Tarun K

2013-12-09T23:59:59.000Z

278

Cosmic Ray Astronomy  

E-Print Network (OSTI)

Cosmic ray astronomy attempts to identify and study the sources of ultrahigh energy cosmic rays. It is unique in its reliance on charged particles as the information carriers. While no discrete source of ultrahigh energy cosmic rays has been identified so far, a new generation of detectors is acquiring the huge exposure that is needed at the highest energies, where deflection by magnetic fields is minimized and the background from distant sources is eliminated by pion photoproduction. In this paper, we summarize the status of cosmic ray astronomy, describing the detectors and the analysis techniques.

Paul Sommers; Stefan Westerhoff

2008-02-09T23:59:59.000Z

279

Gamma Ray Bursts Sudden, intense flashes of gamma rays  

E-Print Network (OSTI)

Gamma Ray Bursts #12;The Case Sudden, intense flashes of gamma rays come from nowhere and disappear with out a trace. Incredibly powerful: A single gamma ray burst is hundreds of times brighter a supernova #12;Who Vela (1960's) Looking for arms testing, found gamma ray bursts Compton Gamma Ray Observatory

Washington at Seattle, University of - Department of Physics, Electroweak Interaction Research Group

280

Elbow mass flow meter  

DOE Patents (OSTI)

The present invention includes a combination of an elbow pressure drop generator and a shunt-type mass flow sensor for providing an output which gives the mass flow rate of a gas that is nearly independent of the density of the gas. For air, the output is also approximately independent of humidity. 3 figs.

McFarland, A.R.; Rodgers, J.C.; Ortiz, C.A.; Nelson, D.C.

1994-08-16T23:59:59.000Z

Note: This page contains sample records for the topic "ray mass attenuation" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


281

The Origins of Mass  

SciTech Connect

The Higgs boson was discovered in July of 2012 and is generally understood to be the origin of mass. While those statements are true, they are incomplete. It turns out that the Higgs boson is responsible for only about 2% of the mass of ordinary matter. In this dramatic new video, Dr. Don Lincoln of Fermilab tells us the rest of the story.

Lincoln, Don

2014-07-30T23:59:59.000Z

282

Gas Chromatography -Mass Spectrometry  

E-Print Network (OSTI)

GCMS - 1 Gas Chromatography - Mass Spectrometry GC-MS ANALYSIS OF ETHANOL AND BENZENE IN GASOLINE Last updated: June 17, 2014 #12;GCMS - 2 Gas Chromatography - Mass Spectrometry GC-MS ANALYSIS). The goal of this experiment is to separate the components in a sample of gasoline using Gas Chromatography

Nizkorodov, Sergey

283

Generating X-ray lines from annihilating dark matter  

E-Print Network (OSTI)

We propose different scenarios where a keV dark matter annihilates to produce a monochromatic signal. The process is generated through the exchange of a light scalar of mass of order 300 keV - 50 MeV coupling to photon through loops or higher dimensional operators. For natural values of the couplings and scales, the model can generate a gamma-ray line which can fit with the recently identified 3.5 keV X-ray line.

Emilian Dudas; Lucien Heurtier; Yann Mambrini

2014-05-08T23:59:59.000Z

284

Sediment resuspension and light attenuation in Peoria Lake: can macrophytes improve water quality in this shallow system?  

Science Journals Connector (OSTI)

We examined sediment resuspension and light attenuation in relation to the ... and clay resulted in frequent periods of sediment resuspension. As calculated (wave theory) shear stress ... measured experimentally)...

William F. James; Elly P. Best; John W. Barko

2004-03-01T23:59:59.000Z

285

W Transverse Mass  

NLE Websites -- All DOE Office Websites (Extended Search)

Some Data Analysis Some Data Analysis The Tevatron produces millions of collisions each second in CDF and DZero. The detectors have hardware triggers to decide if a collision is "interesting," that is it contains a candidate event for any one of a number studies. Our dataset contains 48,844 candidate events for a W mass study. There are other datasets to study Z mass, top and b quarks, QCD, etc. Why don't all the W decays give exactly the same mass? Are all these candidates really Ws? What if we chose only some of these data. How would our choice effect the value of the transverse mass? Work with your classmates. Test the data to see what you can learn. Help with data analysis. Record the best estimate of the W transverse mass from your data analysis. Explain which data you used and why. Check with your classmates and explain any differences between your estimate and theirs.

286

Attenuating Diesel Engine Emissions | U.S. DOE Office of Science (SC)  

Office of Science (SC) Website

Attenuating Diesel Attenuating Diesel Engine Emissions Laboratory Policy and Evaluation (LPE) LPE Home Staff M&O Contracts SC Laboratory Appraisal Process Laboratory Planning Process Work for Others in the Office of Science Laboratory Directed Research and Development (LDRD) DOE's Philosophy on LDRD Frequently Asked Questions Success Stories Brochures Additional Information LDRD Program Contacts Technology Transfer DOE National Laboratories Contact Information Laboratory Policy and Evaluation U.S. Department of Energy SC-32/Forrestal Building 1000 Independence Ave., SW Washington, DC 20585 P: (202) 586-5447 F: (202) 586-3119 Success Stories Attenuating Diesel Engine Emissions Print Text Size: A A A RSS Feeds FeedbackShare Page Early this decade, Argonne chemists developed a special catalyst that can

287

3-D seismic velocity and attenuation structures in the geothermal field  

SciTech Connect

We conducted delay time tomography to determine 3-D seismic velocity structures (Vp, Vs, and Vp/Vs ratio) using micro-seismic events in the geothermal field. The P-and S-wave arrival times of these micro-seismic events have been used as input for the tomographic inversion. Our preliminary seismic velocity results show that the subsurface condition of geothermal field can be fairly delineated the characteristic of reservoir. We then extended our understanding of the subsurface physical properties through determining of attenuation structures (Qp, Qs, and Qs/Qp ratio) using micro-seismic waveform. We combined seismic velocities and attenuation structures to get much better interpretation of the reservoir characteristic. Our preliminary attanuation structures results show reservoir characterization can be more clearly by using the 3-D attenuation model of Qp, Qs, and Qs/Qp ratio combined with 3-D seismic velocity model of Vp, Vs, and Vp/Vs ratio.

Nugraha, Andri Dian [Global Geophysics Research Group, Faculty of Mining and Petroleum Engineering, Institute of Technology Bandung, Jalan Ganesha No. 10 Bandung, 40132 (Indonesia)] [Global Geophysics Research Group, Faculty of Mining and Petroleum Engineering, Institute of Technology Bandung, Jalan Ganesha No. 10 Bandung, 40132 (Indonesia); Syahputra, Ahmad [Geophyisical Engineering, Faculty of Mining and Petroleum Engineering, Institute of Technology Bandung, Jalan Ganesha No. 10 Bandung, 40132 (Indonesia)] [Geophyisical Engineering, Faculty of Mining and Petroleum Engineering, Institute of Technology Bandung, Jalan Ganesha No. 10 Bandung, 40132 (Indonesia); Fatkhan,; Sule, Rachmat [Applied Geophysics Research Group, Faculty of Mining and Petroleum Engineering, Institute of Technology Bandung, Jalan Ganesha No. 10 Bandung, 40132 (Indonesia)] [Applied Geophysics Research Group, Faculty of Mining and Petroleum Engineering, Institute of Technology Bandung, Jalan Ganesha No. 10 Bandung, 40132 (Indonesia)

2013-09-09T23:59:59.000Z

288

Pressure Dependence of High?Frequency Sound Attenuation in the Deep Pacific Ocean  

Science Journals Connector (OSTI)

Vertical and horizontal acoustic paths located in the Pacific Ocean between depths of 910 and 3350 m have been utilized to determine the attenuation of sound at a nominal frequency of 75 kHz. Results from these two different geometries show that predicted values exceed the observed magnitudes of acoustic attenuation at this frequency and at these depths. At 3350 m the predicted value is 22.7 dB/km vs a measured value of 13.3±0.5 dB/km a discrepancy of more than 9 dB. Furthermore increasing pressure reduces the attenuation a fact which supports the work of Fisher [J. Acoust. Soc. Amer. 38 805 (1965)] in contrast to that of Kester and Pytkowicz [Geochimica et Cosmochimica Acta 34 1039 (1970)]. However the amount of reduction is larger than previously suspected by more than 80% [This paper represents results of research sponsored by the Office of Naval Research.

H. F. Bezdek

1972-01-01T23:59:59.000Z

289

A Shallow Attenuating Anomaly Inside The Ring Fracture Of The Valles  

Open Energy Info (EERE)

Shallow Attenuating Anomaly Inside The Ring Fracture Of The Valles Shallow Attenuating Anomaly Inside The Ring Fracture Of The Valles Caldera, New Mexico Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: A Shallow Attenuating Anomaly Inside The Ring Fracture Of The Valles Caldera, New Mexico Details Activities (4) Areas (2) Regions (0) Abstract: Spectral ratios of teleseismic direct and scattered P waves observed in the Valles Caldera, New Mexico, show a systematic pattern of low amplitudes at sites inside the caldera relative to sites on or outside the ring fracture. Waveforms recorded at caldera stations are considerably more complex than those recorded outside the caldera. The data used in this study were collected during a passive seismic monitoring experiment conducted in 1987. Twenty-four teleseismic events were recorded on two

290

E-Print Network 3.0 - accreting low-mass binary Sample Search...  

NLE Websites -- All DOE Office Websites (Extended Search)

C channel to form the Galactic low mass BH binaries... , and for the occurrence of gamma-ray bursts from collapsars in binaries. Rotational eects in accreting white dwarfs......

291

Gamma Ray Bursts  

E-Print Network (OSTI)

Gamma-ray bursts have been detected at photon energies up to tens of GeV. We review some recent developments in the X-ray to GeV photon phenomenology in the light of Swift and Fermi observations, and some of the theoretical models developed to explain them, with a view towards implications for C.T.A.

Peter Mészáros

2012-04-12T23:59:59.000Z

292

Chest x-Rays  

Energy.gov (U.S. Department of Energy (DOE))

The B-reading is a special reading of a standard chest x-ray film performed by a physician certified by the National Institute for Occupational Safety and Health (NIOSH). The reading looks for changes on the chest x-ray that may indicate exposure and disease caused by agents such as asbestos or silica.

293

Gamma ray bursts  

Science Journals Connector (OSTI)

The time histories size spectrum spatial distribution and repetition rates of gamma ray bursts are reviewed briefly. Evidence for a neutron star origin for gamma ray bursts may be found in many of these aspects of bursters. New results from optical searches are described. Substantial progress has been made recently in the optical identificaiton of the 1978 November 19 burst.

K. Hurley

1983-01-01T23:59:59.000Z

294

X-ray beamsplitter  

DOE Patents (OSTI)

An x-ray beamsplitter which splits an x-ray beam into two coherent parts by reflecting and transmitting some fraction of an incident beam has applications for x-ray interferometry, x-ray holography, x-ray beam manipulation, and x-ray laser cavity output couplers. The beamsplitter is formed of a wavelength selective multilayer thin film supported by a very thin x-ray transparent membrane. The beamsplitter resonantly transmits and reflects x-rays through thin film interference effects. A thin film is formed of 5--50 pairs of alternate Mo/Si layers with a period of 20--250 A. The support membrane is 10--200 nm of silicon nitride or boron nitride. The multilayer/support membrane structure is formed across a window in a substrate by first forming the structure on a solid substrate and then forming a window in the substrate to leave a free-standing structure over the window. 6 figs.

Ceglio, N.M.; Stearns, D.G.; Hawryluk, A.M.; Barbee, T.W. Jr.

1987-08-07T23:59:59.000Z

295

X-ray beamsplitter  

DOE Patents (OSTI)

An x-ray beamsplitter which splits an x-ray beam into two coherent parts by reflecting and transmitting some fraction of an incident beam has applications for x-ray interferometry, x-ray holography, x-ray beam manipulation, and x-ray laser cavity output couplers. The beamsplitter is formed of a wavelength selective multilayer thin film supported by a very thin x-ray transparent membrane. The beamsplitter resonantly transmits and reflects x-rays through thin film interference effects. A thin film is formed of 5-50 pairs of alternate Mo/Si layers with a period of 20-250 A. The support membrane is 10-200 nm of silicon nitride or boron nitride. The multilayer/support membrane structure is formed across a window in a substrate by first forming the structure on a solid substrate and then forming a window in the substrate to leave a free-standing structure over the window.

Ceglio, Natale M. (Livermore, CA); Stearns, Daniel S. (Mountain View, CA); Hawryluk, Andrew M. (Modesto, CA); Barbee, Jr., Troy W. (Palo Alto, CA)

1989-01-01T23:59:59.000Z

296

X-ray binaries  

E-Print Network (OSTI)

We review the nuclear astrophysics aspects of accreting neutron stars in X-ray binaries. We summarize open astrophysical questions in light of recent observations and their relation to the underlying nuclear physics. Recent progress in the understanding of the nuclear physics, especially of X-ray bursts, is also discussed.

H. Schatz; K. E. Rehm

2006-08-01T23:59:59.000Z

297

Gamma-ray binaries  

E-Print Network (OSTI)

Recent observations have shown that some compact stellar binaries radiate the highest energy light in the universe. The challenge has been to determine the nature of the compact object and whether the very high energy gamma-rays are ultimately powered by pulsar winds or relativistic jets. Multiwavelength observations have shown that one of the three gamma-ray binaries known so far, PSR B1259-63, is a neutron star binary and that the very energetic gamma-rays from this source and from another gamma-ray binary, LS I +61 303, may be produced by the interaction of pulsar winds with the wind from the companion star. At this time it is an open question whether the third gamma-ray binary, LS 5039, is also powered by a pulsar wind or a microquasar jet, where relativistic particles in collimated jets would boost the energy of the wind from the stellar companion to TeV energies.

I. F. Mirabel

2006-10-24T23:59:59.000Z

298

Mono-Energetic Gamma-ray (MEGa-ray)  

NLE Websites -- All DOE Office Websites (Extended Search)

(MeV) spectral range. MEGa-ray Rendering In the mono-energetic gamma-ray (MEGA-ray) device, electrons and laser photons crash head-on, creating a backscatter of gamma...

299

Frequency-dependent ultrasound attenuation in superfluid H3e in aerogel  

Science Journals Connector (OSTI)

Ultrasound attenuation measurements in the B-like phase of superfluid H3e embedded in 98% porosity aerogel have been performed at four frequencies between 3.6 and 11.3 MHz. At all of the pressures studied (14, 25, and 33 bar), the attenuation exhibits nontrivial frequency dependences that progressively deviate from the hydrodynamic ?2 behavior as the temperature decreases. This behavior is related to the structure of the impurity states inside the gap and could offer a tool to profile the gap structure in this system.

B. H. Moon; N. Masuhara; P. Bhupathi; M. Gonzalez; M. W. Meisel; Y. Lee; N. Mulders

2010-08-03T23:59:59.000Z

300

Mass of Ca-36  

E-Print Network (OSTI)

PH YS ICA 1. RE VIK W C VO I. UMK 15, 5 UMBER 6 Mass of ~Cat R. E. Tribble, ~ J. D. Cossairt, and R. A. Kenefick Cyclotron Institute and Physics Department, Texas AChM University, College Station, Texas 77843 (Received 14 October 1976) The ' Ca...('He, He)' Ca reaction has been used to provide the first observation of the nuclide ' Ca. The Q value and mass excess were found to be ?57.58~0.04 and ?6.44+0.04 MeV, respectively. The new mass completes four members of the A = 36 isobaric quintet...

Tribble, Robert E.; Cossairt, J. D.; Kenefick, R. A.

1977-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "ray mass attenuation" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


301

Ultra High Energy Cosmic Rays and Gamma Ray Bursts from Axion Stars  

E-Print Network (OSTI)

We propose a model in which ultra high energy cosmic rays and gamma ray bursts are produced by collisions between neutron stars and axion stars. The acceleration of such a cosmic ray is made by the electric field, $\\sim 10^{15} (B/10^{12} {G}) {eV} {cm}^{-1}$, which is induced in an axion star by relatively strong magnetic field $B>10^{12}$ G of a neutron star. On the other hand, similar collisions generate gamma ray bursts when magnetic field is relatively small, e.g. $\\leq 10^{10}$ G. Assuming that the axion mass is $\\sim 10^{-9}$ eV, we can explain huge energies of the gamma ray bursts $\\sim 10^{54}$ erg as well as the ultra high energies of the cosmic rays $\\sim 10^{20}$ eV. We estimate rate of energy release in the collisions and we find that the rate roughly agrees with observations. In addition, we show that these axion stars are plausible candidates for MACHOs. Since the axion star induces oscillating electric current under the magnetic field, observable monochromatic radiations are emitted.

Aiichi Iwazaki

2000-08-29T23:59:59.000Z

302

X-ray absorption spectroscopy  

E-Print Network (OSTI)

009-9473-8 REVIEW X-ray absorption spectroscopy Junko Yano Æand application of X-ray absorption spectroscopy, bothX-ray absorption near-edge structure (XANES) and extended X-

Yano, Junko; Yachandra, Vittal K.

2009-01-01T23:59:59.000Z

303

X-ray Absorption Spectroscopy  

E-Print Network (OSTI)

type: Review X-ray Absorption Spectroscopy Junko Yano andPhotosystem II; XAS, X-ray absorption spectroscopy; EXAFS,X-ray absorption fine structure; EPR, electron paramagnetic

Yano, Junko

2010-01-01T23:59:59.000Z

304

A determination of the masses of the components of Cyg X-3  

E-Print Network (OSTI)

The Galactic X-ray binary Cyg X-3 consists of a compact object wind-fed by a Wolf-Rayet (WR) star. We determine its binary parameters and the mass-loss rate. Using the published infrared and X-ray data, we calculate the mass ratio and inclination. Then we fit the dependence of the mass-loss rate on the mass for WR stars of the WN type, and take into account a relation between the mass-loss rate and the binary period derivative, observed to be >0 in Cyg X-3. This allows us to solve for the masses, inclination and mass-loss rate in the system. Our obtained mass-loss rate is almost identical to that from two independent estimates and consistent with other ones, which strongly supports the validity of this solution. We obtain the WR and compact object masses as 10.3(-2.8,+3.9), 2.4(-1.1,+2.1) solar masses, respectively. Thus, either a neutron star or a low-mass black hole can be present. However, the radio, infrared and X-ray properties of the system suggest that the compact object is a black hole.

Zdziarski, Andrzej A; Belczynski, Krzysztof

2012-01-01T23:59:59.000Z

305

A question of mass  

Science Journals Connector (OSTI)

We present a pedagogical discussion of spontaneous symmetry breaking the Goldstone theorem and the Higgs mechanism. If the Higgs boson is found it might provide an explanation of the origin of mass.

Jeremy Bernstein

2011-01-01T23:59:59.000Z

306

Heavy Hybrid mesons Masses  

E-Print Network (OSTI)

We estimate the ground state masses of the heavy hybrid mesons using a phenomenological QCD-type potential. 0^{- -},1^{- -},0^{- +},1^{- +} and 0^{+ -} J^{PC} states are considered.

F. Iddir; L. Semlala

2006-11-13T23:59:59.000Z

307

MASS POLITICAL MOBILIZATION  

E-Print Network (OSTI)

................................................................................................................................................... MASS POLITICAL MOBILIZATION ................................................................................................................................................... Boix & Stokes: The Oxford Handbook of Comparative Politics Boixandstokes-chap21 Revise Proof page 497 20.4.2007 12:41pm #12;Boix & Stokes: The Oxford Handbook of Comparative Politics Boixandstokes-chap21

308

Masses of Fundamental Particles  

E-Print Network (OSTI)

In the original paper entitled, "Masses of Fundamental Particles"(arXiv:1109.3705v5, 10 Feb 2012), not only the masses of fundamental particles including the weak bosons, Higgs boson, quarks, and leptons, but also the mixing angles of quarks and those of neutrinos are all explained and/or predicted in the unified composite models of quarks and leptons successfully. In this addendum entitled, "Higgs Boson Mass in the Minimal Unified Subquark Model", it is emphasized that the Higgs boson mass is predicted to be about 130Gev in the minimal unified subquark model, which agrees well with the experimental values of 125-126GeV recently found by the ATLAS and CMS Collaborations at the LHC.

Hidezumi Terazawa

2014-06-11T23:59:59.000Z

309

Mass of Cd104  

Science Journals Connector (OSTI)

A quadrupole-dipole-dipole-dipole spectrograph has been used with a 34.6 MeV proton beam to observe the Cd106(p, t)Cd104 reaction. The Q value is measured and a mass excess of -83 963(14) keV is inferred for Cd104.NUCLEAR REACTIONS Cd106(p, t)Cd104, E=34.6 MeV; Q value measured; mass excess inferred.

R. A. Dewberry; R. T. Kouzes; R. A. Naumann

1983-02-01T23:59:59.000Z

310

X-ray laser  

DOE Patents (OSTI)

An X-ray laser (10) that lases between the K edges of carbon and oxygen, i.e. between 44 and 23 Angstroms, is provided. The laser comprises a silicon (12) and dysprosium (14) foil combination (16) that is driven by two beams (18, 20) of intense line focused (22, 24) optical laser radiation. Ground state nickel-like dysprosium ions (34) are resonantly photo-pumped to their upper X-ray laser state by line emission from hydrogen-like silicon ions (32). The novel X-ray laser should prove especially useful for the microscopy of biological specimens.

Nilsen, Joseph (Livermore, CA)

1991-01-01T23:59:59.000Z

311

W Transverse Mass  

NLE Websites -- All DOE Office Websites (Extended Search)

Transverse Mass Histogram Transverse Mass Histogram Data for 49,844 candidate W events are in an Excel spreadsheet with the following data as shown in the table below: A B C D 1 Run No Event No W TMass GeV/c2 Bins 2 55237 19588 68.71732 3 55237 30799 72.19464 Get the data. Sort the data by ascending mass. Be sure to sort all the data in the first three columns! Make a histogram of the data. Rather than graphing the data as individual points, physicists group the data by mass. They consider the full range of the data and divide it into "bins" of equal range size. A histogram is a graph of the number of events in each bin vs. the bin range. They are looking for a peak in the data where most of the masses fall. This will be the value of the mass as detemined by that dataset, and the width of the distribution is a reflection of the errors in the measurements.

312

Fabrication and performance of blazed transmission gratings for x-ray astronomy  

E-Print Network (OSTI)

We have developed a new type of soft x-ray diffraction grating. This critical-angle transmission (CAT) grating combines the advantages of traditional transmission gratings (low mass, extremely relaxed alignment and flatness ...

Schattenburg, Mark Lee

313

Supply and demand in the material recovery system for cathode ray tube glass  

E-Print Network (OSTI)

This paper presents an analysis of the material recovery system for leaded glass from cathode ray tubes (CRTs). In particular, the global mass flow of primary and secondary CRT glass and the theoretical capacities for using ...

Nadeau, Marie-Claude

314

EBT2 Dosimetry of X-rays produced by the electron beam from PFMA-3, a Plasma Focus for medical applications  

E-Print Network (OSTI)

The electron beam emitted from the back of Plasma Focus devices is being studied as a radiation source for IORT (IntraOperative Radiation Therapy) applications. A Plasma Focus device is being developed to this aim, to be utilized as an X-ray source. The electron beam is driven to impinge on 50 {\\mu}m brass foil, where conversion X-rays are generated. Measurements with gafchromic film are performed to analyse the attenuation of the X-rays beam and to predict the dose given to the culture cell in radiobiological experiments to follow.

Elisa Ceccolini; Federico Rocchi; Domiziano Mostacci; Marco Sumini; Agostino Tartari

2011-12-09T23:59:59.000Z

315

EBT2 Dosimetry of X-rays produced by the electron beam from PFMA-3, a Plasma Focus for medical applications  

E-Print Network (OSTI)

The electron beam emitted from the back of Plasma Focus devices is being studied as a radiation source for IORT (IntraOperative Radiation Therapy) applications. A Plasma Focus device is being developed to this aim, to be utilized as an X-ray source. The electron beam is driven to impinge on 50 {\\mu}m brass foil, where conversion X-rays are generated. Measurements with gafchromic film are performed to analyse the attenuation of the X-rays beam and to predict the dose given to the culture cell in radiobiological experiments to follow.

Ceccolini, Elisa; Mostacci, Domiziano; Sumini, Marco; Tartari, Agostino

2011-01-01T23:59:59.000Z

316

Study of the seismic attenuation generated by the mud layer in Lake Maracaibo, Venezuela  

E-Print Network (OSTI)

by the gassy sediment in the mud layer, and the high attenuation of the compressional and shear waves. This mud layer sediment is heavy and is not suspended in the water. Furthermore, it is compacted enough to support shear stresses and, therefore, has a...

Perez Arredondo, Javier Antonio

2004-09-30T23:59:59.000Z

317

A replication-deficient rabies virus vaccine expressing Ebola virus glycoprotein is highly attenuated for neurovirulence  

SciTech Connect

We are developing inactivated and live-attenuated rabies virus (RABV) vaccines expressing Ebola virus (EBOV) glycoprotein for use in humans and endangered wildlife, respectively. Here, we further characterize the pathogenesis of the live-attenuated RABV/EBOV vaccine candidates in mice in an effort to define their growth properties and potential for safety. RABV vaccines expressing GP (RV-GP) or a replication-deficient derivative with a deletion of the RABV G gene (RV{Delta}G-GP) are both avirulent after intracerebral inoculation of adult mice. Furthermore, RV{Delta}G-GP is completely avirulent upon intracerebral inoculation of suckling mice unlike parental RABV vaccine or RV-GP. Analysis of RV{Delta}G-GP in the brain by quantitative PCR, determination of virus titer, and immunohistochemistry indicated greatly restricted virus replication. In summary, our findings indicate that RV-GP retains the attenuation phenotype of the live-attenuated RABV vaccine, and RV{Delta}G-GP would appear to be an even safer alternative for use in wildlife or consideration for human use.

Papaneri, Amy B. [Emerging Viral Pathogens Section, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Fort Detrick, MD 21702 (United States)] [Emerging Viral Pathogens Section, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Fort Detrick, MD 21702 (United States); Wirblich, Christoph [Department of Microbiology and Immunology, Jefferson Medical College, Thomas Jefferson University, Philadelphia, PA 19107 (United States)] [Department of Microbiology and Immunology, Jefferson Medical College, Thomas Jefferson University, Philadelphia, PA 19107 (United States); Cann, Jennifer A.; Cooper, Kurt [Integrated Research Facility, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Fort Detrick MD, 21702 (United States)] [Integrated Research Facility, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Fort Detrick MD, 21702 (United States); Jahrling, Peter B. [Emerging Viral Pathogens Section, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Fort Detrick, MD 21702 (United States) [Emerging Viral Pathogens Section, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Fort Detrick, MD 21702 (United States); Integrated Research Facility, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Fort Detrick MD, 21702 (United States); Schnell, Matthias J., E-mail: matthias.schnell@jefferson.edu [Department of Microbiology and Immunology, Jefferson Medical College, Thomas Jefferson University, Philadelphia, PA 19107 (United States); Jefferson Vaccine Center, Jefferson Medical College, Thomas Jefferson University, Philadelphia, PA 19107 (United States); Blaney, Joseph E., E-mail: jblaney@niaid.nih.gov [Emerging Viral Pathogens Section, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Fort Detrick, MD 21702 (United States)

2012-12-05T23:59:59.000Z

318

Frequency-dependent seismic attenuation in shales: experimental results and theoretical analysis  

Science Journals Connector (OSTI)

......decane-saturated Mancos shale observing negligible...dependence of the anisotropic elastic moduli...attenuation has an anisotropic expression and...perpendicular to the shale bedding plane...Batzle M. Anisotropic elastic moduli of the Mancos B Shale-- An experimental......

Claudio Delle Piane; Joel Sarout; Claudio Madonna; Erik H. Saenger; David N. Dewhurst; Mark Raven

2014-01-01T23:59:59.000Z

319

Attenuation of single-tone ultrasound by an atmospheric glow discharge plasma barrier  

E-Print Network (OSTI)

Attenuation of single-tone ultrasound by an atmospheric glow discharge plasma barrier Vadim P through an atmospheric pressure glow discharge in air was studied experimentally. The plasma obtained in and around the plasma using laser-induced Rayleigh scattering technique. Results show

�tügen, Volkan

320

E-Print Network 3.0 - attenuates maladaptive proximal Sample...  

NLE Websites -- All DOE Office Websites (Extended Search)

68 E X E R C I S E A N D M E T A B O L I S M Metabolic Signatures of Exercise in Human Plasma Summary: and were attenuated in subjects with myocardial ischemia. A combination of...

Note: This page contains sample records for the topic "ray mass attenuation" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


321

Blasting Attenuation Study Crystal Ridge, MacDonald Ranch and MacDonald Highlands  

E-Print Network (OSTI)

#12;#12;#12;#12;Blasting Attenuation Study Crystal Ridge, MacDonald Ranch and MacDonald Highlands Ridge, MacDonald Ranch, and MacDonald Highlands. The purpose of this study was to · evaluate seismograph recorded in the Crystal Ridge, MacDonald Ranch, and MacDonald Highlands areas from 2/25/05 to 3

322

Design of a Gust-Attenuation Controller for Landing Operations of Unmanned Autonomous Helicopters  

E-Print Network (OSTI)

Design of a Gust-Attenuation Controller for Landing Operations of Unmanned Autonomous Helicopters landing operations of an Unmanned Autonomous Helicopter (UAH). A heave motion model of an UAH is constructed for the purpose of capturing dynamic variations of thrust due to horizontal wind gusts

Pota, Himanshu Roy

323

TO APPEAR IN TRANSACTIONS ON MOBILE COMPUTING, 2013 1 IVC in Cities: Signal Attenuation by Buildings  

E-Print Network (OSTI)

of energy consumption is negligible. We performed an extensive set of simulations to evaluate the negativeTO APPEAR IN TRANSACTIONS ON MOBILE COMPUTING, 2013 1 IVC in Cities: Signal Attenuation obstacles, especially in cities. Typical concepts address this problem by requiring all vehicles to also act

Breu, Ruth

324

Attenuation of High-Frequency Seismic Waves in Kachchh Region, Gujarat, India  

Science Journals Connector (OSTI)

...India babita_s@rediffmail.com Dinesh Kumar S. S. Teotia Department of Geophysics...Sharma, B. , S. S. Teotia, and Dinesh Kumar (2007). Attenuation of P, S...Author Devi D. Kameswari Author Kumar Dinesh Author Teotia S. S. Author Rastogi...

Babita Sharma; Arun K. Gupta; D. Kameswari Devi; Dinesh Kumar; S. S. Teotia; B. K. Rastogi

325

Attenuation anisotropy and the relative frequency content of split shear waves  

Science Journals Connector (OSTI)

......several important applications. First, in geothermal applications water is pumped from an injector...simple, and requires no extra acquisition costs beyond those required for the shear-wave...attenuation quantifies the difference in energy loss per cycle experienced by S1 and S2......

Andrew J. Carter; J.-Michael Kendall

2006-06-01T23:59:59.000Z

326

Shear wave velocity, seismic attenuation, and thermal structure of the continental upper mantle  

Science Journals Connector (OSTI)

......where E* is the activation energy, R is the gas constant, tau...This is achieved by use of a cost function based on the norm...Petrologic and non-steady-state geothermal constraints available for these...1965. Attenuation of seismic energy in upper mantle, J. geophys......

Irina M. Artemieva; Magali Billien; Jean-Jacques Lévêque; Walter D. Mooney

2004-05-01T23:59:59.000Z

327

Terahertz atmospheric attenuation and continuum effects David M. Slocum,*a  

E-Print Network (OSTI)

Terahertz atmospheric attenuation and continuum effects David M. Slocum,*a Thomas M. Goyette such as pollution monitoring and detection of energetic chemicals are of particular interest. Although there has been much attention to atmospheric effects over narrow frequency windows, accurate measurements across

Massachusetts at Lowell, University of

328

Induced Hypothermia During Resuscitation from Hemorrhagic Shock Attenuates Microvascular Inflammation in the Rat Mesenteric Microcirculation  

E-Print Network (OSTI)

INDUCED HYPOTHERMIA DURING RESUSCITATION FROM HEMORRHAGIC SHOCK ATTENUATES MICROVASCULAR INFLAMMATION IN THE RAT MESENTERIC MICROCIRCULATION BY GARRETT NICHOLAS COYAN BS, UNIVERSITY OF MICHIGAN, 2009 Submitted to the graduate degree... program in Clinical Research and the Graduate Faculty of the University of Kansas in partial fulfillment of the requirements for the degree of Master of Science. ________________________________ Chairperson Edward F. Ellerbeck, MD, MPH...

Coyan, Garrett Nicholas

2013-08-31T23:59:59.000Z

329

REALTIME AUDIO SOURCE SEPARATION BY DELAY AND ATTENUATION COMPENSATION IN THE TIME DOMAIN  

E-Print Network (OSTI)

REAL­TIME AUDIO SOURCE SEPARATION BY DELAY AND ATTENUATION COMPENSATION IN THE TIME DOMAIN.rosca,ningping.fan,radu.balang@scr.siemens.com ABSTRACT There is increased interest in using microphone arrays in a variety of audio source separation to a strongly echoic office with reverber­ ation time of 500 msec. 1. INTRODUCTION Speech enhancement and audio

Balan, Radu V.

330

X-Ray Generators  

Science Journals Connector (OSTI)

There are many types of X-ray generators sold commercially. The following are some of ... that should be considered when selecting a particular generator for a particular purpose. All the companies listed below s...

Reuben Rudman

1972-01-01T23:59:59.000Z

331

Cosmic rays in astrospheres  

E-Print Network (OSTI)

Cosmic rays passing through large astrospheres can be efficiently cooled inside these "cavities" in the interstellar medium. Moreover, the energy spectra of these energetic particles are already modulated in front of the astrospherical bow shocks. We study the cosmic ray flux in and around lambda Cephei as an example for an astrosphere. The large-scale plasma flow is modeled hydrodynamically with radiative cooling. We studied the cosmic ray flux in a stellar wind cavity using a transport model based on stochastic differential equations. The required parameters, most importantly, the elements of the diffusion tensor, are based on the heliospheric parameters. The magnetic field required for the diffusion coefficients is calculated kinematically. We discuss the transport in an astrospheric scenario with varying parameters for the transport coefficients. We show that large stellar wind cavities can act as sinks for the galactic cosmic ray flux and thus can give rise to small-scale anisotropies in the direction to...

Scherer, Klaus; Bomans, Dominik; Ferreira, Stefan; Fichtner, Horst; Kleimann, Jens; Strauss, Dutoit; Weis, Kerstin; Wiengarten, Tobias; Wodzinski, Thomas

2015-01-01T23:59:59.000Z

332

Rapid scanning mass spectrometer  

SciTech Connect

Mass spectrometers and residual gas analyzers (RGA) are used in a variety of applications for analysis of volatile and semi-volatile materials. Analysis is performed by detecting fragments of gas molecules, based on their mass to charge ratio, which are generated in the mass spectrometer. When used as a detector for a gas chromatograph, they function as a means to quantitatively identify isolated volatile species which have been separated from other species via the gas chromatograph. Vacuum Technology, Inc., (VTI) produces a magnetic sector mass spectrometer/RGA which is used in many industrial and laboratory environments. In order to increase the utility of this instrument, it is desirable to increase the mass scanning speed, thereby increasing the number of applications for which it is suited. This project performed the following three upgrades on the computer interface. (1) A new electrometer was designed and built to process the signal from the detector. This new electrometer is more sensitive, over 10 times faster, and over 100 times more stable than the electrometer it will replace. (2) The controller EPROM was reprogrammed with new firmware. This firmware acts as an operating system for the interface and is used to shuttle communications between the PC and the AEROVAC mass spectrometer. (3) The voltage regulator which causes the ion selector voltage to ramp to allow ions of selected mass to be sequentially detected was redesigned and prototyped. The redesigned voltage regulator can be ramped up or down more than 100 times faster than the existing regulator. These changes were incorporated into a prototype unit and preliminary performance testing conducted. Results indicated that scanning speed was significantly increased over the unmodified version.

Leckey, J.H. [Lockheed Martin Energy Systems, Inc., Oak Ridge, TN (United States); Boeckmann, M.D. [Vacuum Technology, Inc., Oak Ridge, TN (United States)

1996-11-25T23:59:59.000Z

333

Gamma-Ray Bursts  

E-Print Network (OSTI)

Gamma-ray bursts are the most luminous explosions in the Universe, and their origin and mechanism are the focus of intense research and debate. More than three decades after their discovery, and after pioneering breakthroughs from space and ground experiments, their study is entering a new phase with the recently launched Swift satellite. The interplay between these observations and theoretical models of the prompt gamma ray burst and its afterglow is reviewed.

P. Meszaros

2006-05-30T23:59:59.000Z

334

Cosmic Rays and Gamma Ray Bursts From Microblazars  

E-Print Network (OSTI)

Highly relativistic jets from merger and accretion induced collapse of compact stellar objects, which may produce the cosmological gamma ray bursts (GRBs), are also very efficient and powerful cosmic ray accelerators. The expected luminosity, energy spectrum and chemical composition of cosmic rays from Galactic GRBs, most of which do not point in our direction, can explain the observed properties of Galactic cosmic rays.

Arnon Dar

1998-09-13T23:59:59.000Z

335

Gamma ray camera  

DOE Patents (OSTI)

A gamma ray camera for detecting rays emanating from a radiation source such as an isotope. The gamma ray camera includes a sensor array formed of a visible light crystal for converting incident gamma rays to a plurality of corresponding visible light photons, and a photosensor array responsive to the visible light photons in order to form an electronic image of the radiation therefrom. The photosensor array is adapted to record an integrated amount of charge proportional to the incident gamma rays closest to it, and includes a transparent metallic layer, photodiode consisting of a p-i-n structure formed on one side of the transparent metallic layer, and comprising an upper p-type layer, an intermediate layer and a lower n-type layer. In the preferred mode, the scintillator crystal is composed essentially of a cesium iodide (CsI) crystal preferably doped with a predetermined amount impurity, and the p-type upper intermediate layers and said n-type layer are essentially composed of hydrogenated amorphous silicon (a-Si:H). The gamma ray camera further includes a collimator interposed between the radiation source and the sensor array, and a readout circuit formed on one side of the photosensor array.

Perez-Mendez, Victor (Berkeley, CA)

1997-01-01T23:59:59.000Z

336

Gamma ray camera  

DOE Patents (OSTI)

A gamma ray camera is disclosed for detecting rays emanating from a radiation source such as an isotope. The gamma ray camera includes a sensor array formed of a visible light crystal for converting incident gamma rays to a plurality of corresponding visible light photons, and a photosensor array responsive to the visible light photons in order to form an electronic image of the radiation therefrom. The photosensor array is adapted to record an integrated amount of charge proportional to the incident gamma rays closest to it, and includes a transparent metallic layer, photodiode consisting of a p-i-n structure formed on one side of the transparent metallic layer, and comprising an upper p-type layer, an intermediate layer and a lower n-type layer. In the preferred mode, the scintillator crystal is composed essentially of a cesium iodide (CsI) crystal preferably doped with a predetermined amount impurity, and the p-type upper intermediate layers and said n-type layer are essentially composed of hydrogenated amorphous silicon (a-Si:H). The gamma ray camera further includes a collimator interposed between the radiation source and the sensor array, and a readout circuit formed on one side of the photosensor array. 6 figs.

Perez-Mendez, V.

1997-01-21T23:59:59.000Z

337

Atomic mass compilation 2012  

SciTech Connect

Atomic mass reflects the total binding energy of all nucleons in an atomic nucleus. Compilations and evaluations of atomic masses and derived quantities, such as neutron or proton separation energies, are indispensable tools for research and applications. In the last decade, the field has evolved rapidly after the advent of new production and measuring techniques for stable and unstable nuclei resulting in substantial ameliorations concerning the body of data and their precision. Here, we present a compilation of atomic masses comprising the data from the evaluation of 2003 as well as the results of new measurements performed. The relevant literature in refereed journals and reports as far as available, was scanned for the period beginning 2003 up to and including April 2012. Overall, 5750 new data points have been collected. Recommended values for the relative atomic masses have been derived and a comparison with the 2003 Atomic Mass Evaluation has been performed. This work has been carried out in collaboration with and as a contribution to the European Nuclear Structure and Decay Data Network of Evaluations.

Pfeiffer, B., E-mail: bpfeiffe@uni-mainz.de [II. Physikalisches Institut, Justus-Liebig-Universität Gießen, Gießen (Germany); GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt (Germany); Venkataramaniah, K. [Sri Sathya Sai Institute of Higher Learning, Prasanthinilayam (India)] [Sri Sathya Sai Institute of Higher Learning, Prasanthinilayam (India); Czok, U. [II. Physikalisches Institut, Justus-Liebig-Universität Gießen, Gießen (Germany)] [II. Physikalisches Institut, Justus-Liebig-Universität Gießen, Gießen (Germany); Scheidenberger, C. [GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt (Germany) [GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt (Germany); II. Physikalisches Institut, Justus-Liebig-Universität Gießen, Gießen (Germany)

2014-03-15T23:59:59.000Z

338

The Evolution of Coronal X-ray Emission  

E-Print Network (OSTI)

as a hydrogen burning star. Rocks were present in the solar system at 1 Myr, the giant planets formed within 10 flares, coronal mass ejections etc. interact(ed) with planetary systems. The properties of the early Sun out (i.e. photoionisation/photodissociation can change chemistry, X-ray/EUV radiation can heat upper

339

SHIELDING ASTRONAUTS FROM COSMIC RAYS E. N. Parker  

E-Print Network (OSTI)

enshrouded mass of Earth is subject to a continuing low dose rate of galactic cosmic radiation. Exposure years. The best available estimates of the accumulated cosmic radiation damage to the astronauts predict of the ongoing radiation damage by the cosmic rays. Unfortunately there is very little information available

Shepherd, Simon

340

E-Print Network 3.0 - attenuates gamma radiation Sample Search...  

NLE Websites -- All DOE Office Websites (Extended Search)

Astrophysics Research Group Collection: Physics 60 MilagroA TeV Observatory for Gamma Ray Bursts Summary: to gamma rays is likely to complement synchrotron radiation and produce...

Note: This page contains sample records for the topic "ray mass attenuation" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


341

Imaging large vessels using cosmic-ray muon energy-loss techniques  

Science Journals Connector (OSTI)

Imaging the internal structure of large vessels (2–20 m in diameter) is not possible with most traditional imaging methods. The sheer size renders gamma-ray and other high-energy photon, neutron, electrical and acoustic techniques useless, whilst the use of high-energy accelerators required to produce charged-particles of sufficient energy are impractical in most industrial situations. The use of naturally occurring high-energy (?GeV) cosmic-ray mu-mesons (muons) provides an effective solution to the penetration problem. The problems of low intensity at near-horizontal angles with the cosmic-ray muon flux are addressed by using energy-loss imaging methods. In other methodologies, using charge-particle energy-loss imaging techniques, only a few events are needed compared to many thousands required if attenuation measurements were to be employed. The energies of horizontal cosmic-ray muons are distributed largely between 0.1 and 1000 GeV with a mean energy of about 50 GeV. Radiation Transport Monte-Carlo methods (GEANT4) have been used to calculate the energy loss for a selection of industrial materials in the energy range of interest. The energy loss of the muons along a ray-sum are modelled and compared to attenuation losses along the ray-sum using energy resolving detectors in coincidence before and after the sample. The energy-loss spectra across different samples are measured, demonstrating that embedded materials can be identified with as few as 10 muons passing through the sample. It is proposed that the imaging modality can be extended into a full tomographic modality allowing material identification within each voxel.

P.M. Jenneson; W.B. Gilboy; S.J.R. Simons; S.J. Stanley; D. Rhodes

2007-01-01T23:59:59.000Z

342

JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 93, NO. B9, PAGES 10,501-10,520, SEPTEMBER 10, 1988 Applicationsof Attenuation Tomogrphy to Imperial Valley and  

E-Print Network (OSTI)

Applicationsof Attenuation Tomogrphy to Imperial Valley and Coso-Indian Wells Region, Southern California ratios in the Imperial Valley and Coso-IndianWells regionsof southern California. In the. In the Imperial ¾alley,slowP wave travel time anomaliesand highly attenuatingS wave anomalies werefoundin the Braw

Clayton, Robert W.

343

The Mass Spectroscope  

Science Journals Connector (OSTI)

... THE handbook, prepared by M. G. Inghram of JL the University of Chicago, and R ... Committee on Nuclear Science of the National Research Council*, presents in some detail the fundamental design and operational techniques pertinent to the efficient utilization of the mass spectroscope. Attention ...

S. WEINTROUB

1955-03-12T23:59:59.000Z

344

Mass Media Science Fellows  

Science Journals Connector (OSTI)

...alternative energy sources, including solar, bio-mass, and geothermal. The changing...assistant secretary for con-servation and solar applications, U.S. Department of Energy...representative of the United Re-public of Tanzania to the United Na-tions, the resolution...

1979-12-07T23:59:59.000Z

345

Residential Thermal Mass Construction  

E-Print Network (OSTI)

The southwest has long known the value of building homes with high mass materials. The ancient Pueblo Indians found that by using "adobe" they could capture the energy necessary to survive the harsh desert climate. Our ancestors knew that a heavy...

Thieken, J. S.

1988-01-01T23:59:59.000Z

346

Top Quark Mass Measurements  

Science Journals Connector (OSTI)

First observed in 1995 the top quark is one of a pair of third?generation quarks in the Standard Model of particle physics. It has charge +2/3e and a mass of 171.4 GeV about 40 times heavier than its partner the bottom quark. The CDF and DØ collaborations have identified several hundred events containing the decays of top?antitop pairs in the large dataset collected at the Tevatron proton?antiproton collider over the last four years. They have used these events to measure the top quark’s mass to nearly 1% precision and to study other top quark properties. The mass of the top quark is a fundamental parameter of the Standard Model and knowledge of its value with small uncertainty allows us to predict properties of the as?yet?unobserved Higgs boson. This paper presents the status of the measurements of the top quark mass. It is based on a talk I gave at the Conference on the Intersections of Particle and Nuclear Physics in Puerto Rico May 2006 which also included discussion of measurements of other top quark properties.

A. P. Heinson; CDF Collaboration; DØ Collaboration

2006-01-01T23:59:59.000Z

347

Mass Extinctions Geology 331  

E-Print Network (OSTI)

into shallow water and released to atmosphere. · Oxidation of coal and hydrocarbons by extensive erosion of sedimentary rocks, and/or massive volcanic eruptions in Siberia? CH2O + O2 CO2 +H2O · Release of methane by rapid influx of C12 caused by methane release and mass dying at the end of the Permian. Organisms

Kammer, Thomas

348

Gauge Invariance and Mass  

Science Journals Connector (OSTI)

It is argued that the gauge invariance of a vector field does not necessarily imply zero mass for an associated particle if the current vector coupling is sufficiently strong. This situation may permit a deeper understanding of nucleonic charge conservation as a manifestation of a gauge invariance, without the obvious conflict with experience that a massless particle entails.

Julian Schwinger

1962-01-01T23:59:59.000Z

349

Can Naked Singularities Yield Gamma Ray Bursts?  

E-Print Network (OSTI)

Gamma-ray bursts are believed to be the most luminous objects in the Universe. There has been some suggestion that these arise from quantum processes around naked singularities. The main problem with this suggestion is that all known examples of naked singularities are massless and hence there is effectively no source of energy. It is argued that a globally naked singularity coupled with quantum processes operating within a distance of the order of Planck length of the singularity will probably yield energy burst of the order of M_pc^2\\approx2\\times 10^{16} ergs, where M_p is the Planck mass.

H. M. Antia

1998-07-09T23:59:59.000Z

350

Gamma Rays from Kaluza-Klein Dark Matter  

Science Journals Connector (OSTI)

A TeV gamma-ray signal from the direction of the Galactic center (GC) has been detected by the HESS experiment. Here, we investigate whether Kaluza-Klein (KK) dark matter annihilations near the GC can be the explanation. Including the contributions from internal bremsstrahlung as well as subsequent decays of quarks and ? leptons, we find a very flat gamma-ray spectrum which drops abruptly at the dark matter particle mass. For a KK mass of about 1 TeV, this gives a good fit to the HESS data below 1 TeV. A similar model, with gauge coupling roughly 3 times as large and a particle mass of about 10 TeV, would give both the correct relic density and a photon spectrum that fits the complete range of data.

Lars Bergström; Torsten Bringmann; Martin Eriksson; Michael Gustafsson

2005-04-08T23:59:59.000Z

351

THE DIVERSE HOT GAS CONTENT AND DYNAMICS OF OPTICALLY SIMILAR LOW-MASS ELLIPTICAL GALAXIES  

SciTech Connect

The presence of hot X-ray-emitting gas is ubiquitous in massive early-type galaxies. However, much less is known about the content and physical status of the hot X-ray gas in low-mass ellipticals. In the present paper, we study the X-ray gas content of four low-mass elliptical galaxies using archival Chandra X-ray observations. The sample galaxies, NGC 821, NGC 3379, NGC 4278, and NGC 4697, have approximately identical K-band luminosities, and hence stellar masses, yet their X-ray appearance is strikingly different. We conclude that the unresolved emission in NGC 821 and NGC 3379 is built up from a multitude of faint compact objects, such as coronally active binaries and cataclysmic variables. Despite the non-detection of X-ray gas, these galaxies may host low density, and hence low luminosity, X-ray gas components, which undergo an outflow driven by a Type Ia supernova (SN Ia). We detect hot X-ray gas with a temperature of kT {approx} 0.35 keV in NGC 4278, the component of which has a steeper surface brightness distribution than the stellar light. Within the central 50'' ({approx}3.9 kpc), the estimated gas mass is {approx}3 Multiplication-Sign 10{sup 7} M{sub Sun }, implying a gas mass fraction of {approx}0.06%. We demonstrate that the X-ray gas exhibits a bipolar morphology in the northeast-southwest direction, indicating that it may be outflowing from the galaxy. The mass and energy budget of the outflow can be maintained by evolved stars and SNe Ia, respectively. The X-ray gas in NGC 4697 has an average temperature of kT {approx} 0.3 keV and a significantly broader distribution than the stellar light. The total gas mass within 90'' ({approx}5.1 kpc) is {approx}2.1 Multiplication-Sign 10{sup 8} M{sub Sun }, hence the gas mass fraction is {approx}0.4%. Based on the distribution and physical parameters of the X-ray gas, we conclude that it is most likely in hydrostatic equilibrium, although a subsonic outflow may be present.

Bogdan, Akos; David, Laurence P.; Jones, Christine; Forman, William R.; Kraft, Ralph P., E-mail: abogdan@cfa.harvard.edu [Smithsonian Astrophysical Observatory, 60 Garden Street, Cambridge, MA 02138 (United States)

2012-10-10T23:59:59.000Z

352

Cosmic Ray Physics  

E-Print Network (OSTI)

Cosmic ray story begins at the beginning of XX century. More then 100 years later, most of the main issues are still open questions, as sources, acceleration mechanism, propagation and composition. There is a continuing fascination with the studies of cosmic radiation mostly from the several contradictions connected to its observation. The radiation has an energy spectrum ranging from $\\sim$ 1 GeV to beyond 10$^{20}$ eV with a flux going from 1 particle per m$^2$ per $\\mu$s to less then 1 particle per km$^2$ per century, and so very different experimental techniques are needed to perform cosmic ray measurements in the different energy intervals. In this contribution the actual experimental status of cosmic ray knowledge will be reviewed.

D'Urso, Domenico

2014-01-01T23:59:59.000Z

353

Viability of primordial black holes as short period gamma-ray bursts  

Science Journals Connector (OSTI)

It has been proposed that the short period gamma-ray bursts, which occur at a rate of ?10?yr-1, may be evaporating primordial black holes (PBHs). Calculations of the present PBH evaporation rate have traditionally assumed that the PBH mass function varies as MBH-5/2. This mass function only arises if the density perturbations from which the PBHs form have a scale invariant power spectrum. It is now known that for a scale invariant power spectrum, normalized to COBE on large scales, the PBH density is completely negligible, so that this mass function is cosmologically irrelevant. For non-scale-invariant power spectra, if all PBHs which form at a given epoch have a fixed mass then the PBH mass function is sharply peaked around that mass, while if the PBH mass depends on the size of the density perturbation from which it forms, as is expected when critical phenomena are taken into account, then the PBH mass function will be far broader than MBH-5/2. In this paper we calculate the present day PBH evaporation rate, using constraints from the diffuse gamma-ray background, for both of these mass functions. If the PBH mass function has a significant finite width, as recent numerical simulations suggest, then it is not possible to produce a present day PBH evaporation rate comparable with the observed short period gamma-ray burst rate. This could also have implications for other attempts to detect evaporating PBHs.

Anne M. Green

2001-12-19T23:59:59.000Z

354

Emission of Radio Waves in Gamma Ray Bursts and Axionic Boson Stars  

E-Print Network (OSTI)

We point out that the bursts of photons with the energy of the axion mass may appear coincidentally with gamma ray bursts if the gamma ray bursts are caused by collisions between neutron stars and axionic boson stars. In this mechanism, jets are formed in the collisions with large Lorentz factors $\\geq 10^2$. We explain qualitatively time-dependent complex structures of gamma ray bursts as well as the large energy problem. Therefore, with detection of the monochromatic photons we can test the model and determine the axion mass.

Aiichi Iwazaki

1999-08-26T23:59:59.000Z

355

Investigating the velocity structure and X-ray observable properties of simulated galaxy clusters with PHOX  

Science Journals Connector (OSTI)

......is essential for mass estimates based on...motions in the gas velocity field within galaxy...et-al. 2012) maps, obtained with X-ray...on the turbulent velocities in a set of galaxy...the large atomic mass of the Fe-xxv ion...supernova (SN) driven winds (Springel Hernquist......

V. Biffi; K. Dolag; H. Böhringer

2013-01-01T23:59:59.000Z

356

Operating the LCLS Gas Attenuator and Gas Detector System with Apertures of 6mm Diameter  

SciTech Connect

The possibility of increasing the apertures of the LCLS gas attenuator/gas detector system is considered. It is shown that increase of the apertures from 3 to 6 mm, together with 4-fold reduction of the operation pressure does not adversely affect the vacuum conditions upstream or downstream. No change of the pump speed and the lengths of the differential pumping cells is required. One minor modification is the use of 1.5 cm long tubular apertures in the end cells of the differential pumping system. Reduction of the pressure does not affect performance of the gas attenuator/gas detector system at the FEL energies below, roughly, 2 keV. Some minor performance degradation occurs at higher energies.

Ryutov, D.D.; Bionta, R.M.; Hau-Riege, S.P.; Kishiyama, K.I.; Roeben, M.D.; Shen, S.; /LLNL, Livermore; Stefan, P.M.; /SLAC; ,

2010-11-17T23:59:59.000Z

357

Technological cost-reduction pathways for attenuator wave energy converters in the marine hydrokinetic environment.  

SciTech Connect

This report considers and prioritizes the primary potential technical costreduction pathways for offshore wave activated body attenuators designed for ocean resources. This report focuses on technical research and development costreduction pathways related to the device technology rather than environmental monitoring or permitting opportunities. Three sources of information were used to understand current cost drivers and develop a prioritized list of potential costreduction pathways: a literature review of technical work related to attenuators, a reference device compiled from literature sources, and a webinar with each of three industry device developers. Data from these information sources were aggregated and prioritized with respect to the potential impact on the lifetime levelized cost of energy, the potential for progress, the potential for success, and the confidence in success. Results indicate the five most promising costreduction pathways include advanced controls, an optimized structural design, improved power conversion, planned maintenance scheduling, and an optimized device profile.

Bull, Diana L; Ochs, Margaret Ellen

2013-09-01T23:59:59.000Z

358

Regional dependence of low?frequency attenuation in the North Pacific Ocean  

Science Journals Connector (OSTI)

A number of experiments based in the South Pacific Ocean have now been reported in which the attenuation of underwater sound at very?low?frequencies displays an apparent regional dependence providing a possible explanation for the considerable spread in at sea attenuation measurements below 1kHz. This regional dependence has been interpreted in terms of acoustic scattering from oceanographic inhomogeneities of various forms and at least two recent theoretical variants based on such a mechanism have been proposed. This paper presents evidence of a similar regional dependency in the North Pacific Ocean and examines the significance of the data to the two theoretical treatments currently most successful in accounting for the effects observed.

A. C. Kibblewhite; N. R. Bedford; S. K. Mitchell

1977-01-01T23:59:59.000Z

359

Reconstruction from Uniformly Attenuated SPECT Projection Data Using the DBH Method  

SciTech Connect

An algorithm was developed for the two-dimensional (2D) reconstruction of truncated and non-truncated uniformly attenuated data acquired from single photon emission computed tomography (SPECT). The algorithm is able to reconstruct data from half-scan (180o) and short-scan (180?+fan angle) acquisitions for parallel- and fan-beam geometries, respectively, as well as data from full-scan (360o) acquisitions. The algorithm is a derivative, backprojection, and Hilbert transform (DBH) method, which involves the backprojection of differentiated projection data followed by an inversion of the finite weighted Hilbert transform. The kernel of the inverse weighted Hilbert transform is solved numerically using matrix inversion. Numerical simulations confirm that the DBH method provides accurate reconstructions from half-scan and short-scan data, even when there is truncation. However, as the attenuation increases, finer data sampling is required.

Huang, Qiu; You, Jiangsheng; Zeng, Gengsheng L.; Gullberg, Grant T.

2008-03-20T23:59:59.000Z

360

THE DUST ATTENUATION LAW IN DISTANT GALAXIES: EVIDENCE FOR VARIATION WITH SPECTRAL TYPE  

SciTech Connect

This Letter utilizes composite spectral energy distributions (SEDs) constructed from NEWFIRM Medium-Band Survey photometry to constrain the dust attenuation curve in 0.5 < z < 2.0 galaxies. Based on similarities between the full SED shapes (0.3-8 ?m), we have divided galaxies in 32 different spectral classes and stacked their photometry. As each class contains galaxies over a range in redshift, the resulting rest-frame SEDs are well sampled in wavelength and show various spectral features including H? and the UV dust bump at 2175 Å. We fit all composite SEDs with flexible stellar population synthesis models, while exploring attenuation curves with varying slopes and UV bump strengths. The Milky Way and Calzetti law provide poor fits at UV wavelengths for nearly all SEDs. Consistent with previous studies, we find that the best-fit attenuation law varies with spectral type. There is a strong correlation between the best-fit dust slope and UV bump strength, with steeper laws having stronger bumps. Moreover, the attenuation curve correlates with specific star formation rate (SFR), with more active galaxies having shallower dust curves and weaker bumps. There is also a weak correlation with inclination. The observed trends can be explained by differences in the dust-to-star geometry, a varying grain size distribution, or a combination of both. Our results have several implications for galaxy evolution studies. First, the assumption of a universal dust model leads to biases in derived galaxy properties. Second, the presence of a dust bump may result in underestimated values for the UV slope, used to correct SFRs of distant galaxies.

Kriek, Mariska [Astronomy Department, University of California at Berkeley, Berkeley, CA 94720 (United States)] [Astronomy Department, University of California at Berkeley, Berkeley, CA 94720 (United States); Conroy, Charlie [Department of Astronomy and Astrophysics, University of California at Santa Cruz, Santa Cruz, CA 95064 (United States)] [Department of Astronomy and Astrophysics, University of California at Santa Cruz, Santa Cruz, CA 95064 (United States)

2013-09-20T23:59:59.000Z

Note: This page contains sample records for the topic "ray mass attenuation" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


361

Variable optical attenuator with a polymer-stabilized dual-frequency liquid crystal  

E-Print Network (OSTI)

Variable optical attenuator with a polymer-stabilized dual-frequency liquid crystal Yung-Hsun Wu. For the DFLC-based homogeneous cell, we use a low- frequency 1 kHz electric field to drive the VOA and a high-frequency, Xiao Liang, Yan-Qing Lu, Fang Du, Yi-Hsin Lin, and Shin-Tson Wu A transmission-type variable optical

Wu, Shin-Tson

362

Sound attenuation in ducts using locally resonant periodic flush mounted flexible silicon aerogel patches  

Science Journals Connector (OSTI)

In recent years low frequency noise has become an important factor especially in the Aircraft HVAC and Automotive industries. In order to reduce this low frequency noise noise attenuation by the classical Helmholtz resonators has size limitations due to the large wavelengths. Promising noise reductions with flush mounted Silicon Aerogel patches can be obtained implementing attenuation due to local resonance and that too without any size constraints. The objective of the current paper is to introduce locally resonant Silicon Aerogel patches flush mounted to an acoustic duct walls aiming at creating frequency stop bands at the low frequency zone (below 500 Hz). Green’s Function is used under the framework of interface response theory to predict the degree of attenuation of the local resonant patches. Realistic techniques for expanding the stop bandwidth have been introduced and difference between the Bragg scattering and the locally resonant mechanism was demonstrated using mathematical models. The effect of the arrays of patches on the effective dynamic density and bulk modulus has also been investigated. It is also shown that the numbers and periodicity of these local resonators also plays role in determining the depth and width of the acoustic band gap.

Maaz Farooqui; Wael Akl

2013-01-01T23:59:59.000Z

363

Activation of farnesoid X receptor attenuates hepatic injury in a murine model of alcoholic liver disease  

SciTech Connect

Highlights: •FXR activity was impaired by chronic ethanol ingestion in a murine model of ALD. •Activation of FXR attenuated alcohol-induced liver injury and steatosis. •Activation of FXR attenuated cholestasis and oxidative stress in mouse liver. -- Abstract: Alcoholic liver disease (ALD) is a common cause of advanced liver disease, and considered as a major risk factor of morbidity and mortality worldwide. Hepatic cholestasis is a pathophysiological feature observed in all stages of ALD. The farnesoid X receptor (FXR) is a member of the nuclear hormone receptor superfamily, and plays an essential role in the regulation of bile acid, lipid and glucose homeostasis. However, the role of FXR in the pathogenesis and progression of ALD remains largely unknown. Mice were fed Lieber-DeCarli ethanol diet or an isocaloric control diet. We used a specific agonist of FXR WAY-362450 to study the effect of pharmacological activation of FXR in alcoholic liver disease. In this study, we demonstrated that FXR activity was impaired by chronic ethanol ingestion in a murine model of ALD. Activation of FXR by specific agonist WAY-362450 protected mice from the development of ALD. We also found that WAY-362450 treatment rescued FXR activity, suppressed ethanol-induced Cyp2e1 up-regulation and attenuated oxidative stress in liver. Our results highlight a key role of FXR in the modulation of ALD development, and propose specific FXR agonists for the treatment of ALD patients.

Wu, Weibin [Department of Biochemistry and Molecular Biology, Shanghai Medical College, Fudan University, Shanghai 200032 (China) [Department of Biochemistry and Molecular Biology, Shanghai Medical College, Fudan University, Shanghai 200032 (China); Institutes of Biomedical Science, Fudan University, Shanghai 200032 (China); Zhu, Bo; Peng, Xiaomin [Department of Biochemistry and Molecular Biology, Shanghai Medical College, Fudan University, Shanghai 200032 (China)] [Department of Biochemistry and Molecular Biology, Shanghai Medical College, Fudan University, Shanghai 200032 (China); Zhou, Meiling, E-mail: meilingzhou2012@gmail.com [Department of Radiology, Zhongshan Hospital of Fudan University and Shanghai Institute of Medical Imaging, Shanghai 200032 (China)] [Department of Radiology, Zhongshan Hospital of Fudan University and Shanghai Institute of Medical Imaging, Shanghai 200032 (China); Jia, Dongwei, E-mail: jiadongwei@fudan.edu.cn [Department of Biochemistry and Molecular Biology, Shanghai Medical College, Fudan University, Shanghai 200032 (China)] [Department of Biochemistry and Molecular Biology, Shanghai Medical College, Fudan University, Shanghai 200032 (China); Gu, Jianxin [Department of Biochemistry and Molecular Biology, Shanghai Medical College, Fudan University, Shanghai 200032 (China) [Department of Biochemistry and Molecular Biology, Shanghai Medical College, Fudan University, Shanghai 200032 (China); Institutes of Biomedical Science, Fudan University, Shanghai 200032 (China)

2014-01-03T23:59:59.000Z

364

Soil attenuation of leachates from low-rank coal combustion wastes: a literature survey. [116 references  

SciTech Connect

In parallel with pursuing the goal of increased utilization of low-rank solid fuels, the US Department of Energy is investigating various aspects associated with the disposal of coal-combustion solid wastes. Concern has been expressed relative to the potential hazards presented by leachates from fly ash, bottom ash and scrubber wastes. This is of particular interest in some regions where disposal areas overlap aquifer recharge regions. The western regions of the United States are characterized by relatively dry alkaline soils which may effect substantial attenuation of contaminants in the leachates thereby reducing the pollution potential. A project has been initiated to study the contaminant uptake of western soils. This effort consists of two phases: (1) preparation of a state-of-the-art document on soil attenuation; and (2) laboratory experimental studies to characterize attenuation of a western soil. The state-of-the-art document, represented herein, presents the results of studies on the characteristics of selected wastes, reviews the suggested models which account for the uptake, discusses the specialized columnar laboratory studies on the interaction of leachates and soils, and gives an overview of characteristics of Texas and Wyoming soils. 116 references, 10 figures, 29 tables.

Gauntt, R. O.; DeOtte, R. E.; Slowey, J. F.; McFarland, A. R.

1984-01-01T23:59:59.000Z

365

Mass Market Demand Response  

NLE Websites -- All DOE Office Websites (Extended Search)

Mass Market Demand Response Mass Market Demand Response Speaker(s): Karen Herter Date: July 24, 2002 - 12:00pm Location: Bldg. 90 Demand response programs are often quickly and poorly crafted in reaction to an energy crisis and disappear once the crisis subsides, ensuring that the electricity system will be unprepared when the next crisis hits. In this paper, we propose to eliminate the event-driven nature of demand response programs by considering demand responsiveness a component of the utility obligation to serve. As such, demand response can be required as a condition of service, and the offering of demand response rates becomes a requirement of utilities as an element of customer service. Using this foundation, we explore the costs and benefits of a smart thermostat-based demand response system capable of two types of programs: (1) a mandatory,

366

Nanoscale mass conveyors  

DOE Patents (OSTI)

A mass transport method and device for individually delivering chargeable atoms or molecules from source particles is disclosed. It comprises a channel; at least one source particle of chargeable material fixed to the surface of the channel at a position along its length; a means of heating the channel; and a means for applying an controllable electric field along the channel, whereby the device transports the atoms or molecules along the channel in response to applied electric field. In a preferred embodiment, the mass transport device will comprise a multiwalled carbon nanotube (MWNT), although other one dimensional structures may also be used. The MWNT or other structure acts as a channel for individual or small collections of atoms due to the atomic smoothness of the material. Also preferred is a source particle of a metal such as indium. The particles move by dissociation into small units, in some cases, individual atoms. The particles are preferably less than 100 nm in size.

Regan, Brian C. (Oakland, CA); Aloni, Shaul (Albany, CA); Zettl, Alexander K. (Kensington, CA)

2008-03-11T23:59:59.000Z

367

Electrospray Ionization Mass Spectrometry  

SciTech Connect

Electrospray Ionization (ESI) is a process whereby gas phase ions are created from molecules in solution. As a solution exits a narrow tube in the presence of a strong electric field, an aerosol of charged droplets are is formed that produces gas phase ions as they it desolvates. ESI-MS comprises the creation of ions by ESI and the determination of their mass to charge ratio (m/z) by MS.

Kelly, Ryan T.; Marginean, Ioan; Tang, Keqi

2014-06-13T23:59:59.000Z

368

Cosmological Implications and Physical Properties of an X-Ray Flux-Limited Sample of Galaxy Clusters  

E-Print Network (OSTI)

The original abstract significantly exceeds the space available here, so here's a brief summary. The abstract is similar to the abstract of astro-ph/0111285 (ApJ, 567, 716) which describes the X-ray galaxy cluster sample HIFLUGCS, the X-ray luminosity--gravitational mass relation, the cluster mass function, and the derived cosmological constraints. Additionally, the fraction of the total gravitating mass in the universe which is contained in intracluster gas is quantified. Furthermore, physical properties of the cluster sample have been studied and analyses of relations between different cluster parameters (including the gas mass fraction, gas temperature, X-ray luminosity, gas mass, gravitational mass, beta, and core radius) are discussed. Also, results from an analysis of XMM-Newton performance verification phase data of Abell 1835 are described.

Thomas H. Reiprich

2003-08-08T23:59:59.000Z

369

X-ray Spectrometry  

Science Journals Connector (OSTI)

These provide excellent energy resolution for a wide range of X-ray energies, from the optical range up to several kiloelectronvolts. ... The Astro-E2 launched in 2005 was the first mission that contained a low-temperature microcalorimeter-based observatory, and three more low-temperature detector-based observatories are being developed (NeXT, Constellation-X, ZEUS). ...

Imre Szalóki; János Osán; René E. Van Grieken

2006-05-10T23:59:59.000Z

370

Gamma?ray bursts  

Science Journals Connector (OSTI)

The distribution of ??ray bursts as observed by BATSE rules out the galactic disk origin and it is consistent with the cosmological origin. Much work is currently done to reconcile galactic halo distribution with the absence of dipole and quadrupole moments in the positions of BATSE bursts. A relativistic expansion of the source is implied by both the halo as well as cosmological origin.

Bohdan Paczy?ski

1993-01-01T23:59:59.000Z

371

Top Mass and Properties  

E-Print Network (OSTI)

The top quark was discovered in 1995. The top quark mass is now well measured at the Tevatron, with uncertainty getting below 1% of the top mass. The world average from last year was 170.9 $\\pm$ 1.8 GeV/$c^2$. The new CDF measurement is 172 $\\pm$ 1.2 (stat) $\\pm$ 1.5 (sys) GeV/$c^2$, and D0 will soon present a new measurement. The top quark mass is an important parameter in the Standard Model, and should be measured as precisely as possible. To learn more about the top quark observed and study possible new physics, other properties also should be measured. At the Tevatron, the charge of the top quark can be measured directly. Examples of other properties studied and reported in this presentation are W helicity, top decay branching ratio to b ($R_b$), searches for $t \\to H b$ and for flavor changing neutral current (FCNC). The results are all consistent with the Standard Model within current statistics. With significantly more data being collected at the Tevatron, precision measurements of the top properties are just starting.

Yen-Chu Chen

2008-05-15T23:59:59.000Z

372

Attenuation of laser power of a focused Gaussian beam during interaction between a laser and powder in coaxial laser cladding  

Science Journals Connector (OSTI)

The power of a focused laser beam with a Gaussian intensity profile attenuated by powder in coaxial laser cladding is investigated experimentally and theoretically, and its resolution model is developed. With some assumptions, it is concluded that the attenuation of laser power is an exponential function and is determined by the powder feed rate, particle moving speed, spraying angles and waist positions and diameters of the laser beam and powder flow, grain diameter and run of the laser beam through the powder flow. The attenuation of laser power increases with powder feed rate or run of laser beam through the powder flow. In the experiment presented, 300?W laser power from a focused Gaussian beam is attenuated by a coaxial powder flow. The experimental results agree well with the values calculated with the developed model.

Jichang Liu; Lijun Li; Yuanzhong Zhang; Xiaozhu Xie

2005-01-01T23:59:59.000Z

373

Constraints on jet X-ray emission in low/hard state X-ray binaries  

E-Print Network (OSTI)

We show that the combination of the similarities between the X-ray properties of low luminosity accreting black holes and accreting neutron stars, combined with the differences in their radio properties argues that the X-rays from these systems are unlikely to be formed in the relativistic jets. Specifically, the spectra of extreme island state neutron stars and low/hard state black holes are known to be indistinguishable, while the power spectra from these systems are known to show only minor differences beyond what would be expected from scaling the characteristic variability frequencies by the mass of the compact object. The spectral and temporal similarities thus imply a common emission mechanism that has only minor deviations from having all key parameters scaling linearly with the mass of the compact object, while we show that this is inconsistent with the observations that the radio powers of neutron stars are typically about 30 times lower than those of black holes at the same X-ray luminosity. We also show that an abrupt luminosity change would be expected when a system makes a spectral state transition from a radiatively inefficient jet dominated accretion flow to a thin disk dominated flow, but that such a change is not seen.

Thomas J. Maccarone

2005-03-31T23:59:59.000Z

374

Oscillations During Thermonuclear X-ray Bursts: A New Probe of Neutron Stars  

E-Print Network (OSTI)

Observations of thermonuclear (Type I) X-ray bursts from neutron stars in low mass X-ray binaries (LMXB) with the Rossi X-ray Timing Explorer (RXTE) have revealed large amplitude, high coherence X-ray brightness oscillations with frequencies in the 300 - 600 Hz range. Substantial spectral and timing evidence point to rotational modulation of the X-ray burst flux as the cause of these oscillations, and it is likely that they reveal the spin frequencies of neutron stars in LMXB from which they are detected. Here I review the status of our knowledge of these oscillations and describe how they can be used to constrain the masses and radii of neutron stars as well as the physics of thermonuclear burning on accreting neutron stars.

Tod E. Strohmayer

1999-11-19T23:59:59.000Z

375

rp Process and Masses of N?Z?34 Nuclides  

Science Journals Connector (OSTI)

High-precision Penning-trap mass measurements of the N?Z?34 nuclides Se68, Se70, Br70m, and Br71 were performed, reaching experimental uncertainties of 0.5–15 keV. The new and improved mass data together with theoretical Coulomb displacement energies were used as input for rp process network calculations. An increase in the effective lifetime of the waiting point nucleus Se68 was found, and more precise information was obtained on the luminosity during a type I x-ray burst along with the final elemental abundances after the burst.

J. Savory; P. Schury; C. Bachelet; M. Block; G. Bollen; M. Facina; C. M. Folden; III; C. Guénaut; E. Kwan; A. A. Kwiatkowski; D. J. Morrissey; G. K. Pang; A. Prinke; R. Ringle; H. Schatz; S. Schwarz; C. S. Sumithrarachchi

2009-03-30T23:59:59.000Z

376

EMSL: Capabilities: Mass Spectrometry: Next-Generation Mass Spectrometry  

NLE Websites -- All DOE Office Websites (Extended Search)

Next-Generation Mass Spectrometry Next-Generation Mass Spectrometry Additional Information Meet the Mass Spectrometry Experts Related EMSL User Projects Mass Spectrometry Tools are Applied to all Science Themes Next-Generation Mass Spectrometry Proteomics Research Resource for Integrative Biology Biological and Environmental Research - PNNL Proteomics PNNL's Biological MS Data and Software Distribution Center Mass Spectrometry brochure EMSL is committed to offering state-of-the-art instruments to its users. At a workshop in January of 2008, EMSL mass spectrometry experts joined experts from many universities, private companies, and government institutions and laboratories at a conference held at the National High Magnetic Field Laboratory in Tallahassee Florida. Workshop participants reviewed the state of the art of high-performance mass spectrometers,

377

Mass spectrometry of proteins of known mass Andrew D. Miranker*  

E-Print Network (OSTI)

deter- mination has two significant advantages. First, the mass accuracy under these conditions to the orifice of the mass analyzer. As a result, there is a local separation of charges at the tip

Miranker, Andrew

378

Geoelectrical Measurement of Multi-Scale Mass Transfer Parameters  

SciTech Connect

Mass transfer affects contaminant transport and is thought to control the efficiency of aquifer remediation at a number of sites within the Department of Energy (DOE) complex. An improved understanding of mass transfer is critical to meeting the enormous scientific and engineering challenges currently facing DOE. Informed design of site remedies and long-term stewardship of radionuclide-contaminated sites will require new cost-effective laboratory and field techniques to measure the parameters controlling mass transfer spatially and across a range of scales. In this project, we sought to capitalize on the geophysical signatures of mass transfer. Previous numerical modeling and pilot-scale field experiments suggested that mass transfer produces a geoelectrical signature—a hysteretic relation between sampled (mobile-domain) fluid conductivity and bulk (mobile + immobile) conductivity—over a range of scales relevant to aquifer remediation. In this work, we investigated the geoelectrical signature of mass transfer during tracer transport in a series of controlled experiments to determine the operation of controlling parameters, and also investigated the use of complex-resistivity (CR) as a means of quantifying mass transfer parameters in situ without tracer experiments. In an add-on component to our grant, we additionally considered nuclear magnetic resonance (NMR) to help parse mobile from immobile porosities. Including the NMR component, our revised study objectives were to: 1. Develop and demonstrate geophysical approaches to measure mass-transfer parameters spatially and over a range of scales, including the combination of electrical resistivity monitoring, tracer tests, complex resistivity, nuclear magnetic resonance, and materials characterization; and 2. Provide mass-transfer estimates for improved understanding of contaminant fate and transport at DOE sites, such as uranium transport at the Hanford 300 Area. To achieve our objectives, we implemented a 3-part research plan involving (1) development of computer codes and techniques to estimate mass-transfer parameters from time-lapse electrical data; (2) bench-scale experiments on synthetic materials and materials from cores from the Hanford 300 Area; and (3) field demonstration experiments at the DOE’s Hanford 300 Area. In a synergistic add-on to our workplan, we analyzed data from field experiments performed at the DOE Naturita Site under a separate DOE SBR grant, on which PI Day-Lewis served as co-PI. Techniques developed for application to Hanford datasets also were applied to data from Naturita. 1. Introduction The Department of Energy (DOE) faces enormous scientific and engineering challenges associated with the remediation of legacy contamination at former nuclear weapons production facilities. Selection, design and optimization of appropriate site remedies (e.g., pump-and-treat, biostimulation, or monitored natural attenuation) requires reliable predictive models of radionuclide fate and transport; however, our current modeling capabilities are limited by an incomplete understanding of multi-scale mass transfer—its rates, scales, and the heterogeneity of controlling parameters. At many DOE sites, long “tailing” behavior, concentration rebound, and slower-than-expected cleanup are observed; these observations are all consistent with multi-scale mass transfer [Haggerty and Gorelick, 1995; Haggerty et al., 2000; 2004], which renders pump-and-treat remediation and biotransformation inefficient and slow [Haggerty and Gorelick, 1994; Harvey et al., 1994; Wilson, 1997]. Despite the importance of mass transfer, there are significant uncertainties associated with controlling parameters, and the prevalence of mass transfer remains a point of debate [e.g., Hill et al., 2006; Molz et al., 2006] for lack of experimental methods to verify and measure it in situ or independently of tracer breakthrough. There is a critical need for new field-experimental techniques to measure mass transfer in-situ and estimate multi-scale and spatially variable mass-transfer parame

Day-Lewis, Frederick; Singha, Kamini; Haggerty, Roy; Johnson, Tim; Binley, Andrew; Lane, John

2014-01-16T23:59:59.000Z

379

An X-ray Galaxy Cluster Survey for Investigations of Dark Energy  

E-Print Network (OSTI)

The amount and nature of dark energy (DE) can be tightly constrained by measuring the spatial correlation features and evolution of a sample of ~ 100,000 galaxy clusters over the redshift range 0ray survey will discover all collapsed structures with mass above 3.5e14 solar masss at redshifts z<2 (i.e. the full range where such objects are expected) in the high Galactic latitude sky. Above this mass threshold the tight correlations between X-ray observables and mass allow direct interpretation of the data. We describe the constraints on Dark Energy that can be inferred from such a survey, using powerful self-calibration techniques to relate the X-ray observables (luminosity and temperature) to the underlying mass.

Z. Haiman; S. Allen; N. Bahcall; M. Bautz; H. Boehringer; S. Borgani; G. Bryan; B. Cabrera; C. Canizares; O. Citterio; A. Evrard; A. Finoguenov; R. Griffiths; G. Hasinger; P. Henry; K. Jahoda; G. Jernigan; S. Kahn; D. Lamb; S. Majumdar; J. Mohr; S. Molendi; R. Mushotzky; G. Pareschi; J. Peterson; R. Petre; P. Predehl; A. Rasmussen; G. Ricker; P. Ricker; P. Rosati; A. Sanderson; A. Stanford; M. Voit; S. Wang; N. White; S. White

2005-07-01T23:59:59.000Z

380

Sensitivity of the FERMI Detectors to Gamma-Ray Bursts from Evaporating Primordial Black Holes (PBHs)  

E-Print Network (OSTI)

Primordial Black Holes (PBHs), which may have been created in the early Universe, are predicted to be detectable by their Hawking radiation. The Fermi Gamma-ray Space Telescope observatory offers increased sensitivity to the gamma-ray bursts produced by PBHs with an initial mass of $\\sim 5\\times 10^{14}$ g expiring today. PBHs are candidate progenitors of unidentified Gamma-Ray Bursts (GRBs) that lack X-ray afterglow. We propose spectral lag, which is the temporal delay between the high and low energy pulses, as an efficient method to identify PBH evaporation events with the Fermi Large Area Telescope (LAT).

T. N. Ukwatta; Jane H. MacGibbon; W. C. Parke; K. S. Dhuga; S. Rhodes; A. Eskandarian; N. Gehrels; L. Maximon; D. C. Morris

2010-03-23T23:59:59.000Z

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381

Cosmic ray research Public lecture  

E-Print Network (OSTI)

energy cosmic rays in Argentina 2 p.m., Wednesday, October 6, 2010 128 Jabara Hall Watkins Visiting powerful, high-energy cosmic rays that periodically bombard Earth. The project includes more than 450

382

The Sensitivity of HAWC to High-Mass Dark Matter Annihilations  

E-Print Network (OSTI)

The High Altitude Water Cherenkov (HAWC) observatory is a wide field-of-view detector sensitive to gamma rays of 100 GeV to a few hundred TeV. Located in central Mexico at 19 degrees North latitude and 4100 m above sea level, HAWC will observe gamma rays and cosmic rays with an array of water Cherenkov detectors. The full HAWC array is scheduled to be operational in Spring 2015. In this paper, we study the HAWC sensitivity to the gamma-ray signatures of high-mass (multi- TeV) dark matter annihilation. The HAWC observatory will be sensitive to diverse searches for dark matter annihilation, including annihilation from extended dark matter sources, the diffuse gamma-ray emission from dark matter annihilation, and gamma-ray emission from non-luminous dark matter subhalos. Here we consider the HAWC sensitivity to a subset of these sources, including dwarf galaxies, the M31 galaxy, the Virgo cluster, and the Galactic center. We simulate the HAWC response to gamma rays from these sources in several well-motivated dark matter annihilation channels. If no gamma-ray excess is observed, we show the limits HAWC can place on the dark matter cross-section from these sources. In particular, in the case of dark matter annihilation into gauge bosons, HAWC will be able to detect a narrow range of dark matter masses to cross-sections below thermal. HAWC should also be sensitive to non-thermal cross-sections for masses up to nearly 1000 TeV. The constraints placed by HAWC on the dark matter cross-section from known sources should be competitive with current limits in the mass range where HAWC has similar sensitivity. HAWC can additionally explore higher dark matter masses than are currently constrained.

A. U. Abeysekara; R. Alfaro; C. Alvarez; J. D. Alvarez; R. Arceo; J. C. Arteaga-Velazquez; H. A. Ayala Solares; A. S. Barber; B. M. Baughman; N. Bautista-Elivar; J. Becerra Gonzalez; E. Belmont; S. Y. BenZvi; D. Berley; M. Bonilla Rosales; J. Braun; R. A. Caballero-Lopez; K. S. Caballero-Mora; A. Carraminana; M. Castillo; U. Cotti; J. Cotzomi; E. de la Fuente; C. De Leon; T. DeYoung; R. Diaz Hernandez; L. Diaz-Cruz; J. C. Diaz-Velez; B. L. Dingus; M. A. DuVernois; R. W. Ellsworth; S. F. E.; D. W. Fiorino; N. Fraija; A. Galindo; F. Garfias; M. M. Gonzalez; J. A. Goodman; V. Grabski; M. Gussert; Z. Hampel-Arias; J. P. Harding; C. M. Hui; P. Huentemeyer; A. Imran; A. Iriarte; P. Karn; D. Kieda; G. J. Kunde; A. Lara; R. J. Lauer; W. H. Lee; D. Lennarz; H. Leon Vargas; E. C. Linares; J. T. Linnemann; M. Longo; R. Luna-Garcia; A. Marinelli; H. Martinez; O. Martinez; J. Martinez-Castro; J. A. J. Matthews; J. McEnery; E. Mendoza Torres; P. Miranda-Romagnoli; E. Moreno; M. Mostafa; L. Nellen; M. Newbold; R. Noriega-Papaqui; T. Oceguera-Becerra; B. Patricelli; R. Pelayo; E. G. Perez-Perez; J. Pretz; C. Riviere; D. Rosa-Gonzalez; J. Ryan; H. Salazar; F. Salesa; A. Sandoval; M. Schneider; S. Silich; G. Sinnis; A. J. Smith; K. Sparks Woodle; R. W. Springer; I. Taboada; P. A. Toale; K. Tollefson; I. Torres; T. N. Ukwatta; L. Villasenor; T. Weisgarber; S. Westerhoff; I. G. Wisher; J. Wood; G. B. Yodh; P. W. Younk; D. Zaborov; A. Zepeda; H. Zhou; K. N. Abazajian

2014-12-09T23:59:59.000Z

383

NuSTAR Observations of X-Ray Binaries  

E-Print Network (OSTI)

As of 2014 August, the Nuclear Spectroscopic Telescope Array (NuSTAR) had observed ~30 X-ray binaries either as part of the planned program, as targets of opportunity, or for instrument calibration. The main science goals for the observations include probing the inner part of the accretion disk and constraining black hole spins via reflection components, providing the first observations of hard X-ray emission from quiescent Low Mass X-ray Binaries (LMXBs), measuring cyclotron lines from accreting pulsars, and studying type I X-ray bursts from neutron stars. Here, we describe the science objectives in more depth and give an overview of the NuSTAR observations that have been carried out to achieve the objectives. These include observation of four "IGR" High Mass X-ray Binaries (HMXBs) discovered by INTEGRAL. We also summarize the results that have been obtained and their implications. Among the IGR HMXBs, we focus on the discovery of a cyclotron line in the spectrum of IGR J17544-2619.

Tomsick, John A; Fuerst, Felix; Harrison, Fiona; Miyasaka, Hiromasa; Tendulkar, Shriharsh; Bhalerao, Varun; Chakrabarty, Deepto; King, Ashley; Miller, Jon M; Natalucci, Lorenzo; Stern, Daniel

2015-01-01T23:59:59.000Z

384

New Limits On Gamma-Ray Emission From Galaxy Clusters  

E-Print Network (OSTI)

Galaxy clusters are predicted to produce gamma-rays through cosmic ray interactions and/or dark matter annihilation, potentially detectable by the Fermi Large Area Telescope (Fermi-LAT). We present a new, independent stacking analysis of Fermi-LAT photon count maps using the 79 richest nearby clusters (zSurvey (2MASS) cluster catalog. We obtain the lowest limit on the photon flux to date, 1.1e-11 ph/s/cm^2 (95% confidence) per cluster in the 0.8--100~GeV band, which corresponds to a luminosity limit of 1.7e44 ph/s. We also constrain the emission limits in a range of narrower energy bands. Scaling to recent cosmic ray acceleration and gamma-ray emission models, we find that cosmic rays represent a negligible contribution to the intra-cluster energy density and gas pressure. Furthermore, either accretion shocks must have lower Mach numbers than usually assumed (2--4) or significantly less than 50% of the baryon mass has been processed through such shocks, and thus, the majo...

Griffin, Rhiannon D; Kochanek, Christopher S

2014-01-01T23:59:59.000Z

385

Diffuse X-rays from the Arches and Quintuplet clusters  

E-Print Network (OSTI)

The origin and initial mass function of young stellar clusters near the Galactic center are still poorly understood. Two of the more prominent ones, the Arches and Quintuplet clusters, may have formed from a shock-induced burst of star formation, given their similar age and proximity to each other. Their unusual mass distribution, however, may be evidence of a contributing role played by other factors, such as stellar capture from regions outside the clusters themselves. Diffuse X-ray emission from these sources provides us with a valuable, albeit indirect, measure of the stellar mass-loss rate from their constituents. Using recent data acquired with Chandra, we can study the nature and properties of the outflow to not only probe the pertinent physical conditions, such as high metallicity, the magnetic field, and so forth, but also to better constrain the stellar distribution within the clusters, in order to identify their formative history. In this paper, we present a set of three-dimensional smoothed particle hydrodynamics simulations of the wind-wind interactions in both the Arches and Quintuplet clusters. We are guided primarily by the currently known properties of the constituent stars, though we vary the mass-loss rates in order to ascertain the dependence of the measured X-ray flux on the assumed stellar characteristics. Our results are compared with the latest observations of the Arches cluster. Our analysis of the Quintuplet cluster may be used as a basis for comparison with future X-ray observations of this source.

Gabriel Rockefeller; Chris L. Fryer; Fulvio Melia; Q. Daniel Wang

2005-01-25T23:59:59.000Z

386

Remnants from Gamma-Ray Bursts  

Science Journals Connector (OSTI)

We model the intermediate-time evolution of a "jetted" gamma-ray burst (GRB) as two blobs of matter colliding with the interstellar medium. We follow the hydrodynamic evolution of this system numerically and calculate the bremsstrahlung and synchrotron images of the remnant. We find that for a burst energy of 1051 ergs the remnant becomes spherical after ~5000 yr, when it has collected ~50 M? of interstellar mass. This result is independent of the exact details of the GRB, such as the opening angle. After this time a gamma-ray burst remnant has an expanding sphere morphology. The similarity to a supernova remnant makes it difficult to distinguish between the two at this stage. The expected number of nonspherical gamma-ray burst remnants is ~0.05 per galaxy for a beaming factor of 0.01 and a burst energy of 1051 ergs. Our results suggest that the double-shell object DEM L316 is not a GRB remnant.

Shai Ayal; Tsvi Piran

2001-01-01T23:59:59.000Z

387

Solar panels as cosmic-ray detectors  

E-Print Network (OSTI)

Due to fundamental limitations of accelerators, only cosmic rays can give access to centre-of- mass energies more than one order of magnitude above those reached at the LHC. In fact, extreme energy cosmic rays (1018 eV - 1020 eV) are the only possibility to explore the 100 TeV energy scale in the years to come. This leap by one order of magnitude gives a unique way to open new horizons: new families of particles, new physics scales, in-depth investigations of the Lorentz symmetries. However, the flux of cosmic rays decreases rapidly, being less than one particle per square kilometer per year above 1019 eV: one needs to sample large surfaces. A way to develop large-effective area, low cost, detectors, is to build a solar panel-based device which can be used in parallel for power generation and Cherenkov light detection. Using solar panels for Cherenkov light detection would combine power generation and a non-standard detection device.

Stella, Carlo; Assis, Pedro; Brogueira, Pedro; Santo, Catarina Espirito; Goncalves, Patricia; Pimenta, Mario; De Angelis, Alessandro

2014-01-01T23:59:59.000Z

388

X-Ray Afterglows from Gamma-Ray Bursts  

Science Journals Connector (OSTI)

We consider possible interpretations of the recently detected X-ray afterglow from the gamma-ray burst source GRB 970228. Cosmological and Galactic models of gamma-ray bursts predict different flux and spectral evolution of X-ray afterglows. We show that models based on adiabatic expansion of relativistic forward shocks require very efficient particle energization or postburst reacceleration during the expansion. Cooling neutron star models predict a very distinctive spectral and flux evolution that can be tested in current X-ray data.

M. Tavani

1997-01-01T23:59:59.000Z

389

"Gravitational mass" of information?  

E-Print Network (OSTI)

We hypothesize possible new types of forces that would be the result of new types of interactions, static and a slow transient, between objects with related information contents (pattern). Such mechanism could make material composition dependence claimed by Fishbach, et al in Eotvos type experiments plausible. We carried out experiments by using a high-resolution scale with the following memories: USB-2 flash drives (1-16GB), DVD and CD disks to determine if such an interaction exist/detectable with a scale resolution of 10 microgram with these test objects. We applied zero information, white noise and 1/f noise type data. Writing or deleting the information in any of these devices causes peculiar negative weight transients, up to milligrams (mass fraction around 10^-5), which is followed by various types of relaxation processes. These relaxations have significantly different dynamics compared to transients observed during cooling after stationary external heating. Interestingly, a USB-1 MP3 player has also developed comparable transient mass loss during playing music. A classical interpretation of the negative weight transients could be absorbed water in hygroscopic components however comparison of relaxation time constants with air humidity data does not support an obvious explanation. Another classical interpretation with certain contribution is the lifting Bernoulli force caused by the circulation due to convection of the warm air. However, in this case all observed time constants with a device should have been the same unless some hidden parameter causes the observed variations. Further studies are warranted to clarify if there is indeed a new force, which is showing up as negative mass at weight measurement when high-density structural information is changed or read out (measured).

Laszlo B. Kish

2007-11-08T23:59:59.000Z

390

Gamma-ray burst models  

Science Journals Connector (OSTI)

...research-article Discussion Meeting Issue Gamma-ray bursts organized by Alan Wells, Ralph...J. Wijers and Martin Rees Gamma-ray burst models Andrew King * * ( ark...various possibilities for making gamma-ray bursts, particularly from close binaries...

2007-01-01T23:59:59.000Z

391

Tunable X-ray source  

DOE Patents (OSTI)

A method for the production of X-ray bunches tunable in both time and energy level by generating multiple photon, X-ray, beams through the use of Thomson scattering. The method of the present invention simultaneously produces two X-ray pulses that are tunable in energy and/or time.

Boyce, James R. (Williamsburg, VA)

2011-02-08T23:59:59.000Z

392

Absolute Values of Neutrino Masses: Status and Prospects  

E-Print Network (OSTI)

Compelling evidences in favor of neutrino masses and mixing obtained in the last years in Super-Kamiokande, SNO, KamLAND and other neutrino experiments made the physics of massive and mixed neutrinos a frontier field of research in particle physics and astrophysics. There are many open problems in this new field. In this review we consider the problem of the absolute values of neutrino masses, which apparently is the most difficult one from the experimental point of view. We discuss the present limits and the future prospects of beta-decay neutrino mass measurements and neutrinoless double-beta decay. We consider the important problem of the calculation of nuclear matrix elements of neutrinoless double-beta decay and discuss the possibility to check the results of different model calculations of the nuclear matrix elements through their comparison with the experimental data. We discuss the upper bound of the total mass of neutrinos that was obtained recently from the data of the 2dF Galaxy Redshift Survey and other cosmological data and we discuss future prospects of the cosmological measurements of the total mass of neutrinos. We discuss also the possibility to obtain information on neutrino masses from the observation of the ultra high-energy cosmic rays (beyond the GZK cutoff). Finally, we review the main aspects of the physics of core-collapse supernovae, the limits on the absolute values of neutrino masses from the observation of SN1987A neutrinos and the future prospects of supernova neutrino detection.

S. M. Bilenky; C. Giunti; J. A. Grifols; E. Masso

2003-03-27T23:59:59.000Z

393

The chemistry of high-mass star formation  

E-Print Network (OSTI)

This paper reviews the chemistry of star-forming regions, with an emphasis on the formation of high-mass stars. We first outline the basic molecular processes in dense clouds, their implementation in chemical models, and techniques to measure molecular abundances. Then, recent observational, theoretical and laboratory developments are reviewed on the subjects of hot molecular cores, cosmic-ray ionization, depletion and deuteration, and oxygen chemistry. The paper concludes with a summary of outstanding problems and future opportunities.

Floris F. S. van der Tak

2005-06-07T23:59:59.000Z

394

Mass of Si-24  

E-Print Network (OSTI)

PHYSICAL REVIEW C VOLUME 22, NUMBER 1 JULY 1980 Mass of Si R. E. Tribble, D. M. Tanner, and A. F. Zeller* Cyclotron Institute and Physics Department, Texas A&M University, College Station, Texas 77843 (Received 11 January 1980) The Si( He, 'He... quintet. The theoretical predictions are from Ref. 14. Nuclides +Si- 4AI Al Mg +Mg 24Na +Na- 4Ne Experimental 4&, 5661(24) 5179(9) 4735(2) 42840. 0) Predicted &&, 5646 5184 4722 4260 15 -5 12 24 +37 +12 -12 -37 ay g@eXQ ~~ thearC C...

Tribble, Robert E.; Tanner, D. M.; Zeller, A. F.

1980-01-01T23:59:59.000Z

395

E-Print Network 3.0 - attenuated vector tomography Sample Search...  

NLE Websites -- All DOE Office Websites (Extended Search)

Kansas State University Collection: Mathematics 2 CAT scan and RadonX-ray transform Relations with the Fourier transform. Dual Radon Summary: Optical Tomography Novel...

396

Cosmic Ray Telescopes  

NLE Websites -- All DOE Office Websites (Extended Search)

Cosmic Ray Muon Detectors Cosmic Ray Muon Detectors Particle Physics Using Nature's Accelerator Somewhere out there is a list of "10 Things a Physics Teacher is Least Likely to Say." If one were to find this list, it would have on it such gems as #7. Let's challenge the PE Dept to a game of rugby and #4. I don't care if you understand the concept, just give me the correct answer to 12 sig figs. Finally, you'd get down to the biggie, the thing physics teachers never say: #1. Let's do a particle physics lab right here at Podunk Corners High! The traditional reasons for this are that everyone knows that particle physics is only done with Vastly Expensive and Complicated Equipment run by casts of thousands of Highly Qualified Scientists and that particle physics is Difficult and Arcane.

397

The Neutron-Hydrogen Mass Difference and the Neutron Mass  

Science Journals Connector (OSTI)

Data in the literature leading to the neutron-hydrogen mass difference and the neutron mass are summarized. The disintegration energy of the deuteron together with the HH-D mass spectroscopic doublet separation apparently yields the best value of n-H=0.755±0.016 Mev and a neutron mass of 1.008,941±0.000,02 mass units. Other transmutation-radioactivity cycles check this value. Several inconsistencies in these data and their possible explanation are pointed out. Experiments of interest for improvement in accuracy and reliability of these values are noted.

W. E. Stephens

1947-01-01T23:59:59.000Z

398

Primordial black hole minimum mass  

SciTech Connect

In this paper we revisit thermodynamic constraints on primordial black hole (PBH) formation in the early universe. Under the assumption that PBH mass is equal to the cosmological horizon mass, one can use the 2nd Law of Thermodynamics to put a lower limit on the PBH mass. In models of PBH formation, however, PBHs are created at some fraction of the horizon mass. We show that this thermodynamic constraint still holds for subhorizon PBH formation.

Chisholm, James R. [Institute for Fundamental Theory, University of Florida, Gainesville, Florida 32611-8440 (United States)

2006-08-15T23:59:59.000Z

399

Mass Transport within Soils  

SciTech Connect

Contaminants in soil can impact human health and the environment through a complex web of interactions. Soils exist where the atmosphere, hydrosphere, geosphere, and biosphere converge. Soil is the thin outer zone of the earth's crust that supports rooted plants and is the product of climate and living organisms acting on rock. A true soil is a mixture of air, water, mineral, and organic components. The relative proportions of these components determine the value of the soil for agricultural and for other human uses. These proportions also determine, to a large extent, how a substance added to soil is transported and/or transformed within the soil (Spositio, 2004). In mass-balance models, soil compartments play a major role, functioning both as reservoirs and as the principal media for transport among air, vegetation, surface water, deeper soil, and ground water (Mackay, 2001). Quantifying the mass transport of chemicals within soil and between soil and atmosphere is important for understanding the role soil plays in controlling fate, transport, and exposure to multimedia pollutants. Soils are characteristically heterogeneous. A trench dug into soil typically reveals several horizontal layers having different colors and textures. As illustrated in Figure 1, these multiple layers are often divided into three major horizons: (1) the A horizon, which encompasses the root zone and contains a high concentration of organic matter; (2) the B horizon, which is unsaturated, lies below the roots of most plants, and contains a much lower organic carbon content; and (3) the C horizon, which is the unsaturated zone of weathered parent rock consisting of bedrock, alluvial material, glacial material, and/or soil of an earlier geological period. Below these three horizons lies the saturated zone - a zone that encompasses the area below ground surface in which all interconnected openings within the geologic media are completely filled with water. Similarly to the unsaturated zone with three major horizons, the saturated zone can be further divided into other zones based on hydraulic and geologic conditions. Wetland soils are a special and important class in which near-saturation conditions exist most of the time. When a contaminant is added to or formed in a soil column, there are several mechanisms by which it can be dispersed, transported out of the soil column to other parts of the environment, destroyed, or transformed into some other species. Thus, to evaluate or manage any contaminant introduced to the soil column, one must determine whether and how that substance will (1) remain or accumulate within the soil column, (2) be transported by dispersion or advection within the soil column, (3) be physically, chemically, or biologically transformed within the soil (i.e., by hydrolysis, oxidation, etc.), or (4) be transported out of the soil column to another part of the environment through a cross-media transfer (i.e., volatilization, runoff, ground water infiltration, etc.). These competing processes impact the fate of physical, chemical, or biological contaminants found in soils. In order to capture these mechanisms in mass transfer models, we must develop mass-transfer coefficients (MTCs) specific to soil layers. That is the goal of this chapter. The reader is referred to other chapters in this Handbook that address related transport processes, namely Chapter 13 on bioturbation, Chapter 15 on transport in near-surface geological formations, and Chapter 17 on soil resuspention. This chapter addresses the following issues: the nature of soil pollution, composition of soil, transport processes and transport parameters in soil, transformation processes in soil, mass-balance models, and MTCs in soils. We show that to address vertical heterogeneity in soils in is necessary to define a characteristic scaling depth and use this to establish process-based expressions for soil MTCs. The scaling depth in soil and the corresponding MTCs depend strongly on (1) the composition of the soil and physical state of the soil, (2) the chemical and physic

McKone, Thomas E.

2009-03-01T23:59:59.000Z

400

Magnetic Pair Creation Transparency in Gamma-Ray Pulsars  

E-Print Network (OSTI)

Magnetic pair creation $\\gamma \\to e^+e^-$ has been at the core of radio pulsar paradigms and central to polar cap models of gamma-ray pulsars for over three decades. The Fermi gamma-ray pulsar population now exceeds 140 sources and has defined an important part of Fermi's science legacy. Among the population characteristics well established is the common occurrence of exponential turnovers in their spectra in the 1--10 GeV range. These turnovers are too gradual to arise from magnetic pair creation in the strong magnetic fields of pulsar inner magnetospheres. By demanding insignificant photon attenuation precipitated by such single-photon pair creation, the energies of these turnovers for Fermi pulsars can be used to compute lower bounds for the typical altitude of GeV band emission. This paper explores such pair transparency constraints below the turnover energy, and updates earlier altitude bound determinations of that have been deployed in various Fermi pulsar papers. For low altitude emission locales, gen...

Story, Sarah A

2014-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "ray mass attenuation" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


401

MR-based Attenuation Correction for PET/MR M. Hofmann1,2  

E-Print Network (OSTI)

MR-based Attenuation Correction for PET/MR M. Hofmann1,2 , F. Steinke1 , I. Bezrukov1,2 , A. Kolb2 acquired at 3T an ultra short echo time (UTE) MR image with TE=0.07ms and 1.1x1.1x1.1 mm3 resolution , P. Aschoff2 , M. Lichy2 , M. Erb2 , T. Nägele2 , M. Brady3 , B. Schölkopf1 , and B. Pichler2 1 Max

402

Combustor oscillation attenuation via the control of fuel-supply line dynamics  

DOE Patents (OSTI)

Combustion oscillation control in combustion systems using hydrocarbon fuels is provided by acoustically tuning a fuel-delivery line to a desired phase of the combustion oscillations for providing a pulse of a fuel-rich region at the oscillating flame front at each time when the oscillation produced pressure in the combustion chamber is in a low pressure phase. The additional heat release produced by burning such fuel-rich regions during low combustion chamber pressure effectively attenuates the combustion oscillations to a selected value. 9 figs.

Richards, G.A.; Gemmen, R.S.

1998-09-22T23:59:59.000Z

403

Combustor oscillation attenuation via the control of fuel-supply line dynamics  

DOE Patents (OSTI)

Combustion oscillation control in combustion systems using hydrocarbon fuels is provided by acoustically tuning a fuel-delivery line to a desired phase of the combustion oscillations for providing a pulse of a fuel-rich region at the oscillating flame front at each time when the oscillation produced pressure in the combustion chamber is in a low pressure phase. The additional heat release produced by burning such fuel-rich regions during low combustion chamber pressure effectively attenuates the combustion oscillations to a selected value.

Richards, George A. (Morgantown, WV); Gemmen, Randall S. (Morgantown, WV)

1998-01-01T23:59:59.000Z

404

Casein Kinase 1?/? Inhibitor PF-5006739 Attenuates Opioid Drug-Seeking Behavior  

Science Journals Connector (OSTI)

In a diurnal monkey model, 6 was tested under L:D conditions at 3.2, 10, and 20 mg/kg, oral. ... Self-administration training and testing occurred in operant chambers (ENV-008CT; Med-Associates, St. Ablans, VT) individually located within sound-attenuating cubicles, which were ventilated with an exhaust fan that also served to mask external noise. ... For reinstatement tests, the baseline was defined as the average response on the 2 days preceding a reinstatement test, while the test was the number of responses on the reinstatement test session. ...

Travis T. Wager; Ramalakshmi Y. Chandrasekaran; Jenifer Bradley; David Rubitski; Helen Berke; Scot Mente; Todd Butler; Angela Doran; Cheng Chang; Katherine Fisher; John Knafels; Shenping Liu; Jeff Ohren; Michael Marconi; George DeMarco; Blossom Sneed; Kevin Walton; David Horton; Amy Rosado; Andy Mead

2014-10-09T23:59:59.000Z

405

High Quality Image of Biomedical Object by X-ray Refraction Based Contrast Computed Tomography  

SciTech Connect

Recently we have developed a new Computed Tomography (CT) algorithm for refraction contrast that uses the optics of diffraction-enhanced imaging. We applied this new method to visualize soft tissue which is not visualized by the current absorption based contrast. The meaning of the contrast that appears in refraction-contrast X-ray CT images must be clarified from a biologic or anatomic point of view. It has been reported that the contrast is made with the specific gravity map with a range of approximately 10 {mu}arc sec. However, the relationship between the contrast and biologic or anatomic findings has not been investigated, to our knowledge. We compared refraction-contrast X-ray CT images with microscopic X-ray images, and we evaluated refractive indexes of pathologic lesions on phase-contrast X-ray CT images. We focused our attenuation of breast cancer and lung cancer as samples. X-ray refraction based Computed Tomography was appeared to be a pathological ability to depict the boundary between cancer nest and normal tissue, and inner structure of the disease.

Hashimoto, E. [Department of Photon-Science, School of Advanced Studies, Graduate University for Advanced Studies (GUAS), Shonan Village, Hayama, Kanagawa 240-0193 (Japan); Maksimenko, A.; Hirano, K.; Hyodo, K. [Photon Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); Sugiyama, H. [Department of Photon-Science, School of Advanced Studies, Graduate University for Advanced Studies (GUAS), Shonan Village, Hayama, Kanagawa 240-0193 (Japan); Photon Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); Shimao, D. [Department of Health Sciences, Ibaraki prefectural University of Health Sciences, 4669-2Ami, Ami, Inashiki, Ibaraki, 300-0394 (Japan); Nishino, Y.; Ishikawa, T. [RIKEN Harima Institute, 1-1-1 Kouto, Mikazuki, Sayo, Hyogo, 679-5148 (Japan); Yuasa, T. [Department of Bio-system Engineering, Faculty of Engineering Yamagata University, 4-3-16 Jonan, Yonezawa, Yamagata 992-8510 (Japan); Ichihara, S. [Dept. of Path., Nagoya Med. Center, Nat. Hospital Organization, Naka-ku, Nagoya 460-0001 (Japan); Arai, Y. [Matsumoto Dental University, 1980 Hirooka, Shiojiri, Nagano (Japan); Ando, M. [Department of Photon-Science, School of Advanced Studies, Graduate University for Advanced Studies (GUAS), Shonan Village, Hayama, Kanagawa 240-0193 (Japan); Photon Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); Inst. of Sci. and Tech., Tokyo Univ. of Science, Yamasaki 2641, Noda, Chiba 278-8510 (Japan)

2007-01-19T23:59:59.000Z

406

THREE NEW GALACTIC CENTER X-RAY SOURCES IDENTIFIED WITH NEAR-INFRARED SPECTROSCOPY  

SciTech Connect

We have conducted a near-infrared spectroscopic survey of 47 candidate counterparts to X-ray sources discovered by the Chandra X-Ray Observatory near the Galactic center (GC). Though a significant number of these astrometric matches are likely to be spurious, we sought out spectral characteristics of active stars and interacting binaries, such as hot, massive spectral types or emission lines, in order to corroborate the X-ray activity and certify the authenticity of the match. We present three new spectroscopic identifications, including a Be high-mass X-ray binary (HMXB) or a ? Cassiopeiae (Cas) system, a symbiotic X-ray binary, and an O-type star of unknown luminosity class. The Be HMXB/? Cas system and the symbiotic X-ray binary are the first of their classes to be spectroscopically identified in the GC region.

DeWitt, Curtis [Department of Physics, University of California, Davis, CA 95616 (United States); Bandyopadhyay, Reba M.; Eikenberry, Stephen S.; Sarajedini, Ata [Department of Astronomy, University of Florida, 211 Bryant Space Center, P.O. Box 112055, Gainesville, FL 32611 (United States); Sellgren, Kris [Department of Astronomy, The Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States); Blum, Robert; Olsen, Knut [National Optical Astronomy Observatories, Tucson, AZ 85719 (United States); Bauer, Franz E., E-mail: curtis.n.dewitt@nasa.gov [Departamento de Astronomía y Astrofísica, Pontificia Universidad Católica de Chile, Casilla 306, Santiago 22 (Chile)

2013-11-01T23:59:59.000Z

407

Relative recovery of galactic and anomalous cosmic rays at 1 AU: Further evidence for modulation in the heliosheath  

E-Print Network (OSTI)

as the inclination of the heliospheric neutral current sheet decreases from 32° to its minimum value of 8°. INDEX TERMS: 2104 Interplanetary Physics: Cosmic rays; 2124 Interplanetary Physics: Heliopause and solar wind: anomalous cosmic rays, heliosheath, coronal mass ejections, interplanetary shocks, solar wind, galactic

Reames, Donald V.

408

The mass production and quality control of RPCs for the Daya Bay Experiment  

SciTech Connect

Resistive plate chambers will be used in the Daya Bay reactor neutrino experiment to help veto backgrounds created by cosmic-ray muons. The mass production of RPCs began in 2008 and by the end of 2009, 1600 RPCs (3500 m{sup 2}) had been produced and tested. This paper describes the production and quality control procedures, and quality assurance using cosmic-ray testing.

Hackenburg R.

2011-03-30T23:59:59.000Z

409

Precision Spectroscopy of Pionic Atoms: From Pion Mass Evaluation to Tests of Chiral Perturbation Theory  

E-Print Network (OSTI)

Preliminary results of the strong interaction shift and width in pionic hydrogen ($\\pi H$) using an X-ray spectrometer with spherically bent crystals and CCDs as X-ray detector are presented. In the experiment at the Paul Scherrer Institute three different $(np\\to 1s)$ transitions in $\\pi H$ were measured. Moreover the pion mass measurement using the $(5 \\to 4)$ transitions in pionic nitrogen and muonic oxygen is presented

Trassinelli, M

2004-01-01T23:59:59.000Z

410

X-ray Spectrometry  

Science Journals Connector (OSTI)

The segmented STJ operated at total count rates of above 105 counts/s, and the best-achieved energy resolution of their single STJ was found to be 10 eV for X-ray energies below 1 keV. ... The Mo?Au TES, with an operating temperature of 230 mK, was developed for the Constellation-X mission and the energy resolution of the spectrometer is ?28 eV at 3.3 keV. ...

Imre Szalóki; Szabina B. Török; Jasna Injuk; René E. Van Grieken

2002-05-18T23:59:59.000Z

411

Short Gamma-Ray Bursts from Binary Neutron Star Mergers  

E-Print Network (OSTI)

We present the results from new relativistic hydrodynamic simulations of binary neutron star mergers using realistic non-zero temperature equations of state. We vary several unknown parameters in the system such as the neutron star (NS) masses, their spins and the nuclear equation of state. The results are then investigated with special focus on the post-merger torus-remnant system. Observational implications on the Gamma-ray burst (GRB) energetics are discussed and compared with recent observations.

Roland Oechslin; Thomas Janka

2006-04-27T23:59:59.000Z

412

Development of atmospheric cosmic-ray showers. II  

Science Journals Connector (OSTI)

In a recent paper Orford and Turver criticized one of our previous papers which had concluded that a change in cosmic-ray primary mass composition was required in the energy range 1015 to 1017 eV. It is suggested here, in reply, that the inconsistencies and shortcomings claimed by Orford and Turver are largely not substantiated in the light of available information and that, in the absence of new ideas, the original conclusions are valid.

Greg Thornton and Roger Clay

1981-05-01T23:59:59.000Z

413

A comprehensive range of X-ray ionized reflection models  

E-Print Network (OSTI)

X-ray ionized reflection occurs when a surface is irradiated with X-rays so intense that its ionization state is determined by the ionization parameter xi propto F/n, where F is the incident flux and n the gas density. It occurs in accretion, onto compact objects including black holes in both active galaxies and stellar-mass binaries, and possibly in gamma-ray bursts. Computation of model reflection spectra is often time-consuming. Here we present the results from a comprehensive grid of models computed with our code, which has now been extended to include what we consider to be all energetically-important ionization states and transitions. This grid is being made available as an ionized-reflection model, REFLION, for XSPEC.

R. R. Ross; A. C. Fabian

2005-01-07T23:59:59.000Z

414

Explosive hydrogen burning during type I X-ray bursts  

SciTech Connect

Explosive hydrogen burning in type I X-ray bursts (XRBs) is driven by charged particle reactions creating isotopes with masses up to A {approx} 100. Since charged particle reactions in a stellar environment are very temperature sensitive, we use a realistic time-dependent general relativistic and self-consistent model of type I X-ray bursts to provide accurate values of the burst temperatures and densities. This allows a detailed and accurate time-dependent identification of the reaction flow from the surface layers through the convective region and the ignition region to the neutron star ocean. Using this, we determine the relative importance of specific nuclear reactions in the X-ray burst.

Fisker, J L; Schatz, H; Thielemann, F

2007-06-11T23:59:59.000Z

415

DISCOVERY OF X-RAY EMISSION FROM YOUNG SUNS IN THE SMALL MAGELLANIC CLOUD  

SciTech Connect

We report the discovery of extended X-ray emission within the young star cluster NGC 602a in the Wing of the Small Magellanic Cloud (SMC) based on observations obtained with the Chandra X-Ray Observatory. X-ray emission is detected from the cluster core area with the highest stellar density and from a dusty ridge surrounding the H II region. We use a census of massive stars in the cluster to demonstrate that a cluster wind or wind-blown bubble is unlikely to provide a significant contribution to the X-ray emission detected from the central area of the cluster. We therefore suggest that X-ray emission at the cluster core originates from an ensemble of low- and solar-mass pre-main-sequence (PMS) stars, each of which would be too weak in X-rays to be detected individually. We attribute the X-ray emission from the dusty ridge to the embedded tight cluster of the newborn stars known in this area from infrared studies. Assuming that the levels of X-ray activity in young stars in the low-metallicity environment of NGC 602a are comparable to their Galactic counterparts, then the detected spatial distribution, spectral properties, and level of X-ray emission are largely consistent with those expected from low- and solar-mass PMS stars and young stellar objects (YSOs). This is the first discovery of X-ray emission attributable to PMS stars and YSOs in the SMC, which suggests that the accretion and dynamo processes in young, low-mass objects in the SMC resemble those in the Galaxy.

Oskinova, L. M.; Hainich, R. [Institute for Physics and Astronomy, University Potsdam, D-14476 Potsdam (Germany)] [Institute for Physics and Astronomy, University Potsdam, D-14476 Potsdam (Germany); Sun, W.; Chen, Y. [Department of Astronomy, Nanjing University, Nanjing, 210093 Jiangsu (China)] [Department of Astronomy, Nanjing University, Nanjing, 210093 Jiangsu (China); Evans, C. J. [UK Astronomy Technology Centre, Royal Observatory Edinburgh, Blackford Hill, Edinburgh EH9 3HJ (United Kingdom)] [UK Astronomy Technology Centre, Royal Observatory Edinburgh, Blackford Hill, Edinburgh EH9 3HJ (United Kingdom); Henault-Brunet, V. [Scottish Universities Physics Alliance (SUPA), Institute for Astronomy, University of Edinburgh, Blackford Hill, Edinburgh EH9 3HJ (United Kingdom)] [Scottish Universities Physics Alliance (SUPA), Institute for Astronomy, University of Edinburgh, Blackford Hill, Edinburgh EH9 3HJ (United Kingdom); Chu, Y.-H.; Gruendl, R. A. [Department of Astronomy, University of Illinois, 1002 West Green Street, Urbana, IL 61801 (United States)] [Department of Astronomy, University of Illinois, 1002 West Green Street, Urbana, IL 61801 (United States); Gallagher, J. S. III [Department of Astronomy, University of Wisconsin-Madison, 5534 Sterling, 475 North Charter Street, Madison, WI 53706 (United States)] [Department of Astronomy, University of Wisconsin-Madison, 5534 Sterling, 475 North Charter Street, Madison, WI 53706 (United States); Guerrero, M. A. [Instituto de Astrofisica de Andalucia, IAA-CSIC, Glorieta de la Astronomia s/n, E-18008 Granada (Spain)] [Instituto de Astrofisica de Andalucia, IAA-CSIC, Glorieta de la Astronomia s/n, E-18008 Granada (Spain); Guedel, M. [Department of Astrophysics, University of Vienna, Tuerkenschanzstrasse 17, A-1180 Vienna (Austria)] [Department of Astrophysics, University of Vienna, Tuerkenschanzstrasse 17, A-1180 Vienna (Austria); Silich, S. [Instituto Nacional de Astrofisica Optica y Electronica, AP 51, 72000 Puebla (Mexico)] [Instituto Nacional de Astrofisica Optica y Electronica, AP 51, 72000 Puebla (Mexico); Naze, Y. [GAPHE, Departement AGO, Universite de Liege, Allee du 6 Aout 17, Bat. B5C, B-4000 Liege (Belgium)] [GAPHE, Departement AGO, Universite de Liege, Allee du 6 Aout 17, Bat. B5C, B-4000 Liege (Belgium); Reyes-Iturbide, J. [LATO-DCET/Universidade Estadual de Santa Cruz, Rodovia Jorge Amado, km 16, 45662-000 Ilheus, BA (Brazil)] [LATO-DCET/Universidade Estadual de Santa Cruz, Rodovia Jorge Amado, km 16, 45662-000 Ilheus, BA (Brazil)

2013-03-01T23:59:59.000Z

416

Natural and Enhanced Attenuation of Chlorinated Solvents Using RT3D  

SciTech Connect

RT3D (Reactive Transport in 3-Dimensions) is a reactive transport code that can be applied to model solute fate and transport for many different purposes. This document specifically addresses application of RT3D for modeling related to evaluation and implementation of Monitored Natural Attenuation (MNA). Selection of MNA as a remedy requires an evaluation process to demonstrate that MNA will meet the remediation goals. The U.S. EPA, through the Office of Solid Waste and Emergency Response (OSWER) Directive 9200.4?17P, provides the regulatory context for the evaluation and implementation of MNA. In a complementary fashion, the context for using fate and transport modeling as part of MNA evaluation is described in the EPA?s technical protocol for chlorinated solvent MNA, the Scenarios Evaluation Tool for Chlorinated Solvent MNA, and in this document. The intent of this document is to describe (1) the context for applying RT3D for chlorinated solvent MNA and (2) the attenuation processes represented in RT3D, (3) dechlorination reactions that may occur, and (4) the general approach for using RT3D reaction modules (including a summary of the RT3D reaction modules that are available) to model fate and transport of chlorinated solvents as part of MNA or for combinations of MNA and selected types of active remediation.

Johnson, Christian D.; Truex, Michael J.; Clement, T P.

2006-07-25T23:59:59.000Z

417

Constraining axion by polarized prompt emission from gamma ray bursts  

E-Print Network (OSTI)

A polarized gamma ray emission spread over a sufficiently wide energy band from a strongly magnetized astrophysical object like gamma ray bursts (GRBs) offers an opportunity to test the hypothesis of invisible axion. The axionic induced dichroism of gamma rays at different energies should cause a misalignment of the polarization plane for higher energy events relative to that one for lower energies events resulting in the loss of statistics needed to form a pattern of the polarization signal to be recognized in a detector. According to this, any evidence of polarized gamma rays coming from an object with extended magnetic field could be interpreted as a constraint on the existence of the invisible axion for a certain parameter range. Based on reports of polarized MeV emission detected in several GRBs we derive a constraint on the axion-photon coupling. This constraint $\\g_{a\\gamma\\gamma}\\le 2.2\\cdot 10^{-11} {\\rm GeV^{-1}}$ calculated for the axion mass $m_a=10^{-3} {\\rm eV}$ is competitive with the sensitivity of CAST and becomes even stronger for lower masses.

A. Rubbia; A. S. Sakharov

2007-08-21T23:59:59.000Z

418

Cosmic-ray Driven Outflows in Global Galaxy Disk Models  

E-Print Network (OSTI)

Galactic-scale winds are a generic feature of massive galaxies with high star formation rates across a broad range of redshifts. Despite their importance, a detailed physical understanding of what drives these mass-loaded global flows has remained elusive. In this paper, we explore the dynamical impact of cosmic rays by performing the first three-dimensional, adaptive mesh refinement simulations of an isolated starbursting galaxy that includes a basic model for the production, dynamics and diffusion of galactic cosmic rays. We find that including cosmic rays naturally leads to robust, massive, bipolar outflows from our 10^12 Msun halo, with a mass-loading factor Mout/SFR = 0.3 for our fiducial run. Other reasonable parameter choices led to mass-loading factors above unity. The wind is multiphase and is accelerated to velocities well in excess of the escape velocity. We employ a two-fluid model for the thermal gas and relativistic CR plasma and model a range of physics relevant to galaxy formation, including r...

Salem, Munier

2013-01-01T23:59:59.000Z

419

Anoxic Plume Attenuation in a Fluctuating Water Table System: Impact of 100-D Area In Situ Redox Manipulation on Downgradient Dissolved Oxygen Concentrations  

SciTech Connect

Anoxic Plume Attenuation in a Fluctuating Water Table System: Impact of 100-D Area In Situ Redox Manipulation on Downgradient Dissolved Oxygen Concentrations

Williams, Mark D.; Vermeul, Vincent R.; Oostrom, Martinus; Evans, John C.; Fruchter, Jonathan S.; Istok, J. D.; Humphrey, M. D.; Lanigan, David C.; Szecsody, James E.; White, Mark D.; Wietsma, Thomas W.; Cole, Charles R.

1999-06-14T23:59:59.000Z

420

A Novel Approach to Estimate Diffuse Attenuation Coefficients for QuickBird Satellite Images: A Case Study at Kish Island, the Persian Gulf  

Science Journals Connector (OSTI)

Diffuse attenuation coefficient (k d ) is a critical parameter for benthic habitat mapping using remotely sensed data. This research attempted to develop a new a...

Keivan Kabiri; Biswajeet Pradhan…

2013-12-01T23:59:59.000Z

Note: This page contains sample records for the topic "ray mass attenuation" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


421

Mini ion trap mass spectrometer  

DOE Patents (OSTI)

An ion trap is described which operates in the regime between research ion traps which can detect ions with a mass resolution of better than 1:10{sup 9} and commercial mass spectrometers requiring 10{sup 4} ions with resolutions of a few hundred. The power consumption is kept to a minimum by the use of permanent magnets and a novel electron gun design. By Fourier analyzing the ion cyclotron resonance signals induced in the trap electrodes, a complete mass spectra in a single combined structure can be detected. An attribute of the ion trap mass spectrometer is that overall system size is drastically reduced due to combining a unique electron source and mass analyzer/detector in a single device. This enables portable low power mass spectrometers for the detection of environmental pollutants or illicit substances, as well as sensors for on board diagnostics to monitor engine performance or for active feedback in any process involving exhausting waste products. 10 figs.

Dietrich, D.D.; Keville, R.F.

1995-09-19T23:59:59.000Z

422

Mini ion trap mass spectrometer  

DOE Patents (OSTI)

An ion trap which operates in the regime between research ion traps which can detect ions with a mass resolution of better than 1:10.sup.9 and commercial mass spectrometers requiring 10.sup.4 ions with resolutions of a few hundred. The power consumption is kept to a minimum by the use of permanent magnets and a novel electron gun design. By Fourier analyzing the ion cyclotron resonance signals induced in the trap electrodes, a complete mass spectra in a single combined structure can be detected. An attribute of the ion trap mass spectrometer is that overall system size is drastically reduced due to combining a unique electron source and mass analyzer/detector in a single device. This enables portable low power mass spectrometers for the detection of environmental pollutants or illicit substances, as well as sensors for on board diagnostics to monitor engine performance or for active feedback in any process involving exhausting waste products.

Dietrich, Daniel D. (Livermore, CA); Keville, Robert F. (Valley Springs, CA)

1995-01-01T23:59:59.000Z

423

Electron Effective Mass in Graphene  

E-Print Network (OSTI)

The particle effective mass in graphene is a challenging concept because the commonly used theoretical expression is mathematically divergent. In this paper, we use basic principles to present a simple theoretical expression for the effective mass that is suitable for both parabolic and non-parabolic isotropic materials. We demonstrate that this definition is consistent with the definition of the cyclotron effective mass, which is one of the common methods for effective mass measurement in solid state materials. We apply the proposed theoretical definition to graphene and demonstrate linear dependence of the effective mass on momentum, as confirmed by experimental cyclotron resonance measurements. Therefore, the proposed definition of the effective mass can be used for non-parabolic materials such as graphene.

Viktor Ariel; Amir Natan

2012-06-26T23:59:59.000Z

424

The Magnetic Centrifugal Mass Filter  

SciTech Connect

Mass filters using rotating plasmas have been considered for separating nuclear waste and spent nuclear fuel. We propose a new mass filter that utilizes centrifugal and magnetic confinement of ions in a way similar to the asymmetric centrifugal trap. This magnetic centrifugal mass filter is shown to be more proliferation resistant than present technology. This filter is collisional and produces well confined output streams, among other advantages. __________________________________________________

Abraham J. Fetterman and Nathaniel J. Fisch

2011-08-04T23:59:59.000Z

425

Microsoft Word - ray_abstract  

NLE Websites -- All DOE Office Websites (Extended Search)

Change of electron capture nuclear decay rate in different media and under compression Amlan Ray Variable Energy Cyclotron Center 1AF, Bidhan Nagar Kolkata - 700064 India The...

426

Gamma-ray burst populations.  

E-Print Network (OSTI)

??Over the last fifty years the field of gamma-ray bursts has shown incredible growth, but the amassing of data has also left observers and theorists… (more)

Virgili, Francisco J.

2011-01-01T23:59:59.000Z

427

X-ray Absorption Spectroscopy  

SciTech Connect

This review gives a brief description of the theory and application of X-ray absorption spectroscopy, both X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS), especially, pertaining to photosynthesis. The advantages and limitations of the methods are discussed. Recent advances in extended EXAFS and polarized EXAFS using oriented membranes and single crystals are explained. Developments in theory in understanding the XANES spectra are described. The application of X-ray absorption spectroscopy to the study of the Mn4Ca cluster in Photosystem II is presented.

Yano, Junko; Yachandra, Vittal K.

2009-07-09T23:59:59.000Z

428

X-ray fluorescence mapping  

NLE Websites -- All DOE Office Websites (Extended Search)

biololgical cells, over the measurement of impurities in solar cells, to the rare earth content of geological materials. A somewhat 'typical' layout for a X-ray fluorescence...

429

Relativistic mass and modern physics  

E-Print Network (OSTI)

At first sight, arguments for and against the notion of relativistic mass look like a notorious intra-Lilliputian quarrel between Big-Endians (those who broke their eggs at the larger end) and Little-Endians. However, upon closer inspection we discover that the relativistic mass notion is alien to the spirit of modern physics to a much greater extent than it seems. To demonstrate an abyss between the modern approach and archaic notions, in this paper we explore how the concept of mass is introduced in modern physics. This modern approach reveals a deep cohomological origin of mass.

Z. K. Silagadze

2014-12-15T23:59:59.000Z

430

Phenomenology of Absolute Neutrino Masses  

E-Print Network (OSTI)

The phenomenology of absolute neutrino masses is reviewed, focusing on tritium beta decay, cosmological measurements and neutrinoless double-beta decay.

Carlo Giunti

2004-12-11T23:59:59.000Z

431

Energy Functional for Nuclear Masses.  

E-Print Network (OSTI)

??An energy functional is formulated for mass calculations of nuclei across the nuclear chart with major-shell occupations as the relevant degrees of freedom. The functional… (more)

Bertolli, Michael Giovanni

2011-01-01T23:59:59.000Z

432

Gauge Invariance and Mass. II  

Science Journals Connector (OSTI)

The possibility that a vector gauge field can imply a nonzero mass particle is illustrated by the exact solution of a one-dimensional model.

Julian Schwinger

1962-12-01T23:59:59.000Z

433

Technetium Activities at Mass 97  

Science Journals Connector (OSTI)

A technetium activity believed to be Tc97g has been observed to decay with molybdenum K x-rays and to possess a half-life in the range of 104 to 105 years.

G. E. Boyd

1954-07-01T23:59:59.000Z

434

Light Curves of Swift Gamma Ray Bursts  

E-Print Network (OSTI)

Recent observations from the Swift gamma-ray burst mission indicate that a fraction of gamma ray bursts are characterized by a canonical behaviour of the X-ray afterglows. We present an effective theory which allows us to account for X-ray light curves of both (short - long) gamma ray bursts and X-ray rich flashes. We propose that gamma ray bursts originate from massive magnetic powered pulsars.

Paolo Cea

2006-09-22T23:59:59.000Z

435

E-Print Network 3.0 - attenuates skeletal muscle Sample Search...  

NLE Websites -- All DOE Office Websites (Extended Search)

Collection: Biology and Medicine 5 ORIGINAL ARTICLE Kristina Csukly Tanguy Marqueste Phillip Gardiner Summary: of skeletal muscle mass is particularly sensitive to mechanical...

436

On neutron numbers and atomic masses  

Science Journals Connector (OSTI)

On neutron numbers and atomic masses ... Assigning neutron numbers, correct neutron numbers, and atomic masses and nucleon numbers. ...

R. Heyrovská

1992-01-01T23:59:59.000Z

437

Ultrahigh Energy Cosmic Rays and Prompt TeV Gamma Rays from Gamma Ray Bursts  

E-Print Network (OSTI)

Gamma Ray Bursts (GRBs) have been proposed as one {\\it possible} class of sources of the Ultrahigh Energy Cosmic Ray (UHECR) events observed up to energies $\\gsim10^{20}\\ev$. The synchrotron radiation of the highest energy protons accelerated within the GRB source should produce gamma rays up to TeV energies. Here we briefly discuss the implications on the energetics of the GRB from the point of view of the detectability of the prompt TeV gamma rays of proton-synchrotron origin in GRBs in the up-coming ICECUBE muon detector in the south pole.

Pijushpani Bhattacharjee; Nayantara Gupta

2003-05-12T23:59:59.000Z

438

Gamma Ray Bursts and Their Afterglows  

Science Journals Connector (OSTI)

Gamma?Ray Bursts are extreme astrophysical events which emit the bulk of their energy as photons in the 0.1 – 1.0 MeV range and whose durations span milliseconds to tens of minutes. They are formed in extreme relativistic outflows with Lorentz factors of hundreds and reside at cosmological distances. They are followed by X?ray optical and radio afterglows which can be observed for over a year after the event. Observations of afterglows showed that the emission is from jets and when corrected for this geometry the energies of GRBs appear to cluster around 5 × 1050 erg — very comparable to that of supernovae. Evidence in the last several years shows that a significant fraction of long GRBs are related to a peculiar type of supernova explosions. These supernovae most likely mark the birth events of stellar mass black holes as the final products of the evolution of very massive stars. Short bursts are still somewhat mysterious but it is known that some of them are produced by an old population of stars. Neutron star merger is a leading candidate as the progenitor of short GRBs.

Re’em Sari

2006-01-01T23:59:59.000Z

439

What are the Neutrino Masses  

E-Print Network (OSTI)

The possible source of the production of neutrino with large masses is considered. For this purpose the reaction nu+n to e+p+gamma, in which the electron in neW+ vertex is produced off-mass-shell, is studied.

V. P. Efrosinin

2009-04-03T23:59:59.000Z

440

MULTI-WAVELENGTH STUDY OF THE Be/X-RAY BINARY MXB 0656-072  

SciTech Connect

We present and analyze the optical photometric and spectroscopic data of the Be/X-ray binary MXB 0656-072 from 2006 to 2009. A 101.2 day orbital period is found, for the first time, from the present public X-ray data (Swift/BAT and RXTE/ASM). The anti-correlation between the H{alpha} emission and the UBV brightness of MXB 0656-072 during our 2007 observations indicates that a mass ejection event took place in the system. After the mass ejection, a low-density region might develop around the Oe star. With the outward motion of the circumstellar disk, the outer part of the disk interacted with the neutron star around its periastron passage and a series of X-ray outbursts were triggered between MJD 54350 and MJD 54850. The Proportional Counter Array-HEXTE spectra during the 2007-2008 X-ray outbursts could be well fitted by a cutoff power law with low-energy absorption, together with an iron line around 6.4 keV, and a broad cyclotron resonance feature around 30 keV. The same variability of the soft and hard X-ray colors in 2.3-21 keV indicated that there were no overall changes in the spectral shape during the X-ray outbursts, which might only be connected with the changes of the mass accretion rate onto the neutron star.

Yan Jingzhi; Li Hui; Liu Qingzhong [Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008 (China); Zurita Heras, Juan Antonio; Chaty, Sylvain, E-mail: jzyan@pmo.ac.cn, E-mail: hli@pmo.ac.cn, E-mail: qzliu@pmo.ac.cn, E-mail: juan-antonio.zurita-heras@cea.fr, E-mail: sylvain.chaty@cea.fr [Laboratoire AIM, CEA/DSM-CNRS-Universite Paris Diderot, IRFU/Service d'Astrophysique, FR-91191 Gif-sur-Yvette (France)

2012-07-01T23:59:59.000Z

Note: This page contains sample records for the topic "ray mass attenuation" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


441

A Population of Ultraluminous X-ray Sources with An Accreting Neutron Star  

E-Print Network (OSTI)

Most ultraluminous X-ray sources (ULXs) are believed to be X-ray binary systems, but previous observational and theoretical studies tend to prefer a black hole rather than a neutron star accretor. The recent discovery of 1.37 s pulsations from the ULX M82 X-2 has established its nature as a magnetized neutron star. In this work we model the formation history of neutron star ULXs in an M82- or Milky Way-like galaxy, by use of both binary population synthesis and detailed binary evolution calculations. We find that the birthrate is around $10^{-4}\\, \\rm yr^{-1}$ for the incipient X-ray binaries in both cases. We demonstrate the distribution of the ULX population in the donor mass - orbital period plane. Our results suggest that, compared with black hole X-ray binaries, neutron star X-ray binaries may significantly contribute to the ULX population, and high-mass and intermediate-mass X-ray binaries dominate the neutron star ULX population in M82- and Milky Way-like galaxies, respectively.

Shao, Yong

2015-01-01T23:59:59.000Z

442

Cosmic Rays and Experiment CZELTA  

SciTech Connect

This paper gives a review of the physics of cosmic rays with emphasis on the methods of detection and study. A summary is given of the Czech project CZELTA which is part of a multinational program to study cosmic rays with energies above 10{sup 14} eV.

Smolek, Karel; Nyklicek, Michal [Institute of Experimental and Applied Physics, Czech Technical University in Prague, Horska 3a/22, 128 00 Prague 2 (Czech Republic); Kovacikova, Petra [Faculty of Philosophy and Science, Silesian University in Opava, Bezrucovo namesti 13, 746 01 Opava (Czech Republic)

2007-11-26T23:59:59.000Z

443

Gamma-ray events thunderclouds  

E-Print Network (OSTI)

stage of rocket-triggered lightning #12;The gamma-ray flash occurred at the same time the upward leader radiation is also produced by natural lightning during the stepped leader phase. · Dwyer et al. 2003, 2004 found that x-rays are also produced by triggered lightning dart leaders. · At present, the only viable

California at Berkeley, University of

444

On the broken ray transform  

E-Print Network (OSTI)

This PhD thesis studies the broken ray transform, a generalization of the geodesic X-ray transform where geodesics are replaced with broken rays that reflect on a part of the boundary. The fundamental question is whether this transform is injective. We employ four different methods to approach this question, and each of them gives interesting results. Direct calculation can be used in a ball, where the geometry is particularly simple. If the reflecting part of the boundary is (piecewise) flat, a reflection argument can be used to reduce the problem to the usual X-ray transform. In some geometries one can use broken rays near the boundary to determine the values of the unknown function at the reflector, and even construct its Taylor series. One can also use energy estimates -- which in this context are known as Pestov identities -- to show injectivity in the presence of one convex reflecting obstacle. Many of these methods work also on Riemannian manifolds. We also discuss the periodic broken ray transform, where the integrals are taken over periodic broken rays. The broken ray transform and its periodic version have applications in other inverse problems, including Calder\\'on's problem and problems related to spectral geometry. A more detailed abstract can be found in the PDF file. This version only contains the introductory parts of the thesis. The full thesis also contains five articles.

Joonas Ilmavirta

2014-09-26T23:59:59.000Z

445

The Origin of Cosmic Rays  

ScienceCinema (OSTI)

Cosmic Rays reach the Earth from space with energies of up to more than 1020 eV, carrying information on the most powerful particle accelerators that Nature has been able to assemble. Understanding where and how cosmic rays originate has required almost one century of investigations, and, although the last word is not written yet, recent observations and theory seem now to fit together to provide us with a global picture of the origin of cosmic rays of unprecedented clarity. Here we will describe what we learned from recent observations of astrophysical sources (such as supernova remnants and active galaxies) and we will illustrate what these observations tell us about the physics of particle acceleration and transport. We will also discuss the ?end? of the Galactic cosmic ray spectrum, which bridges out attention towards the so called ultra high energy cosmic rays (UHECRs). At ~1020 eV the gyration scale of cosmic rays in cosmic magnetic fields becomes large enough to allow us to point back to their sources, thereby allowing us to perform ?cosmic ray astronomy?, as confirmed by the recent results obtained with the Pierre Auger Observatory. We will discuss the implications of these observations for the understanding of UHECRs, as well as some questions which will likely remain unanswered and will be the target of the next generation of cosmic ray experiments.

Pasquale Blasi

2010-01-08T23:59:59.000Z

446

X-ray shearing interferometer  

DOE Patents (OSTI)

An x-ray interferometer for analyzing high density plasmas and optically opaque materials includes a point-like x-ray source for providing a broadband x-ray source. The x-rays are directed through a target material and then are reflected by a high-quality ellipsoidally-bent imaging crystal to a diffraction grating disposed at 1.times. magnification. A spherically-bent imaging crystal is employed when the x-rays that are incident on the crystal surface are normal to that surface. The diffraction grating produces multiple beams which interfere with one another to produce an interference pattern which contains information about the target. A detector is disposed at the position of the image of the target produced by the interfering beams.

Koch, Jeffrey A. (Livermore, CA)

2003-07-08T23:59:59.000Z

447

The Sensitivity of HAWC to High-Mass Dark Matter Annihilations  

E-Print Network (OSTI)

The High Altitude Water Cherenkov (HAWC) observatory is a wide field-of-view detector sensitive to gamma rays of 100 GeV to a few hundred TeV. Located in central Mexico at 19 degrees North latitude and 4100 m above sea level, HAWC will observe gamma rays and cosmic rays with an array of water Cherenkov detectors. The full HAWC array is scheduled to be operational in Summer 2014. In this paper, we study the HAWC sensitivity to the gamma-ray signatures of high-mass (multi-TeV) dark matter annihilation. The HAWC observatory will be sensitive to diverse searches for dark matter annihilation, including annihilation from extended dark matter sources, the diffuse gamma-ray emission from dark matter annihilation, and gamma-ray emission from non-luminous dark matter subhalos. Here we consider the HAWC sensitivity to a subset of these sources, including dwarf galaxies, the M31 galaxy, the Virgo cluster, and the Galactic center. We simulate the HAWC response to gamma rays from these sources in several well-motivated dark matter annihilation channels. If no gamma-ray excess is observed, we show the limits HAWC can place on the dark matter cross-section from these sources. In particular, in the case of dark matter annihilation into gauge bosons, HAWC will be able to detect a narrow range of dark matter masses to cross-sections below thermal. HAWC should also be sensitive to non-thermal cross-sections for masses up to nearly 1000 TeV. The constraints placed by HAWC on the dark matter cross-section from known sources should be competitive with current limits.

A. U. Abeysekara; R. Alfaro; C. Alvarez; J. D. Álvarez; R. Arceo; J. C. Arteaga-Velázquez; H. A. Ayala Solares; A. S. Barber; B. M. Baughman; N. Bautista-Elivar; J. Becerra Gonzalez; E. Belmont; S. Y. BenZvi; D. Berley; M. Bonilla Rosales; J. Braun; R. A. Caballero-Lopez; K. S. Caballero-Mora; A. Carramiñana; M. Castillo; U. Cotti; J. Cotzomi; E. de la Fuente; C. De León; T. DeYoung; R. Diaz Hernandez; L. Diaz-Cruz; J. C. D\\'\\iaz-Vélez; B. L. Dingus; M. A. DuVernois; R. W. Ellsworth; S. F. E.; D. W. Fiorino; N. Fraija; A. Galindo; F. Garfias; M. M. González; J. A. Goodman; V. Grabski; M. Gussert; Z. Hampel-Arias; J. P. Harding; C. M. Hui; P. Hüntemeyer; A. Imran; A. Iriarte; P. Karn; D. Kieda; G. J. Kunde; A. Lara; R. J. Lauer; W. H. Lee; D. Lennarz; H. León Vargas; E. C. Linares; J. T. Linnemann; M. Longo; R. Luna-Garcia; A. Marinelli; H. Martinez; O. Martinez; J. Mart\\'\\inez-Castro; J. A. J. Matthews; J. McEnery; E. Mendoza Torres; P. Miranda-Romagnoli; E. Moreno; M. Mostafá; L. Nellen; M. Newbold; R. Noriega-Papaqui; T. Oceguera-Becerra; B. Patricelli; R. Pelayo; E. G. Pérez-Pérez; J. Pretz; C. Rivière; D. Rosa-González; J. Ryan; H. Salazar; F. Salesa; A. Sandoval; M. Schneider; S. Silich; G. Sinnis; A. J. Smith; K. Sparks Woodle; R. W. Springer; I. Taboada; P. A. Toale; K. Tollefson; I. Torres; T. N. Ukwatta; L. Villaseñor; T. Weisgarber; S. Westerhoff; I. G. Wisher; J. Wood; G. B. Yodh; P. W. Younk; D. Zaborov; A. Zepeda; H. Zhou; K. N. Abazajian

2014-05-07T23:59:59.000Z

448

An effective medium study of surface plasmon polaritons in nanostructured gratings using attenuated total reflection  

SciTech Connect

Recent work studied surface plasmon resonances in structured materials by the method of attenuated total reflection using a prism on top of a metallic grating. That calculation considered Transverse Magnetic polarized radiation, involved an expansion in 121 Fourier modes, and found a number of interesting features. Many of these features were attributed to localized plasmons or other factors, which arise from a discrete structure. We use a simple effective medium theory to address the same problem, and find many of the same reflection features observed in the more complex calculation, indicating that localization is not an important factor. We also evaluate the possibility of using some of the new features in the reflection spectrum for bio-sensing and find that the sensitivity of the system to small changes in relative permittivity is increased compared to some standard methods.

Tyboroski, M. H.; Anderson, N. R.; Camley, R. E. [UCCS BioFrontiers Center, University of Colorado at Colorado Springs, Colorado Springs, Colorado 80918 (United States)

2014-01-07T23:59:59.000Z

449

Improved UTE-based attenuation correction for cranial PET-MR using dynamic magnetic field monitoring  

SciTech Connect

Purpose: Ultrashort echo time (UTE) MRI has been proposed as a way to produce segmented attenuation maps for PET, as it provides contrast between bone, air, and soft tissue. However, UTE sequences require samples to be acquired during rapidly changing gradient fields, which makes the resulting images prone to eddy current artifacts. In this work it is demonstrated that this can lead to misclassification of tissues in segmented attenuation maps (AC maps) and that these effects can be corrected for by measuring the true k-space trajectories using a magnetic field camera. Methods: The k-space trajectories during a dual echo UTE sequence were measured using a dynamic magnetic field camera. UTE images were reconstructed using nominal trajectories and again using the measured trajectories. A numerical phantom was used to demonstrate the effect of reconstructing with incorrect trajectories. Images of an ovine leg phantom were reconstructed and segmented and the resulting attenuation maps were compared to a segmented map derived from a CT scan of the same phantom, using the Dice similarity measure. The feasibility of the proposed method was demonstrated inin vivo cranial imaging in five healthy volunteers. Simulated PET data were generated for one volunteer to show the impact of misclassifications on the PET reconstruction. Results: Images of the numerical phantom exhibited blurring and edge artifacts on the bone–tissue and air–tissue interfaces when nominal k-space trajectories were used, leading to misclassification of soft tissue as bone and misclassification of bone as air. Images of the tissue phantom and thein vivo cranial images exhibited the same artifacts. The artifacts were greatly reduced when the measured trajectories were used. For the tissue phantom, the Dice coefficient for bone in MR relative to CT was 0.616 using the nominal trajectories and 0.814 using the measured trajectories. The Dice coefficients for soft tissue were 0.933 and 0.934 for the nominal and measured cases, respectively. For air the corresponding figures were 0.991 and 0.993. Compared to an unattenuated reference image, the mean error in simulated PET uptake in the brain was 9.16% when AC maps derived from nominal trajectories was used, with errors in the SUV{sub max} for simulated lesions in the range of 7.17%–12.19%. Corresponding figures when AC maps derived from measured trajectories were used were 0.34% (mean error) and ?0.21% to +1.81% (lesions). Conclusions: Eddy current artifacts in UTE imaging can be corrected for by measuring the true k-space trajectories during a calibration scan and using them in subsequent image reconstructions. This improves the accuracy of segmented PET attenuation maps derived from UTE sequences and subsequent PET reconstruction.

Aitken, A. P.; Giese, D.; Tsoumpas, C.; Schleyer, P.; Kozerke, S.; Prieto, C.; Schaeffter, T., E-mail: Tobias.Schaeffter@kcl.ac.uk [Department of Biomedical Engineering, Division of Imaging Sciences and Biomedical Engineering, King's College London, King's Health Partners, St. Thomas Hospital, London SE1 7EH (United Kingdom)

2014-01-15T23:59:59.000Z

450

Functional composites of plasmas and metamaterials: Flexible waveguides, and variable attenuators with controllable phase shift  

SciTech Connect

Numerical predictions and experimental results in this study verify that plasmas with negative permittivity work as functional media for electromagnetic waves and that their composites with metallic metamaterials show further extraordinary properties. Chain structures of individual plasmas with negative permittivity, forming a straight line and a L-shaped bent line, serve flexible waveguides via coupling structures of localized surface waves standing around each plasma. Further progresses as wave controllers are achievable in an array of the composites of plasmas and micro metallic resonators; functions of phase shifters and attenuators are individually controlled, with rotation of working points on the complex refractive index plane by varying gas conditions and permeability modulation. Such proposed sets of flexible combination will lead to advanced scientific products with novel functions.

Sakai, Osamu; Maeda, Jun; Shimomura, Takuya [Department of Electronic Science and Engineering, Kyoto University, Kyoto-daigaku Katsura, Nishikyo-ku, Kyoto 615-8510 (Japan)] [Department of Electronic Science and Engineering, Kyoto University, Kyoto-daigaku Katsura, Nishikyo-ku, Kyoto 615-8510 (Japan); Urabe, Keiichiro [Department of Electronic Science and Engineering, Kyoto University, Kyoto-daigaku Katsura, Nishikyo-ku, Kyoto 615-8510 (Japan) [Department of Electronic Science and Engineering, Kyoto University, Kyoto-daigaku Katsura, Nishikyo-ku, Kyoto 615-8510 (Japan); Department of Advanced Materials Science, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa-shi, Chiba 277-8561 (Japan)

2013-07-15T23:59:59.000Z

451

Thermal Acoustic Sensor for High Pulse Energy X-ray FEL Beams  

SciTech Connect

The pulse energy density of X-ray FELs will saturate or destroy conventional X-ray diagnostics, and the use of large beam attenuation will result in a beam that is dominated by harmonics. We present preliminary results at the LCLS from a pulse energy detector based on the thermal acoustic effect. In this type of detector an X-ray resistant material (boron carbide in this system) intercepts the beam. The pulse heating of the target material produces an acoustic pulse that can be detected with high frequency microphones to produce a signal that is linear in the absorbed energy. The thermal acoustic detector is designed to provide first- and second-order calorimetric measurement of X-ray FEL pulse energy. The first-order calorimetry is a direct temperature measurement of a target designed to absorb all or most of the FEL pulse power with minimal heat leak. The second-order measurement detects the vibration caused by the rapid thermoelastic expansion of the target material each time it absorbs a photon pulse. Both the temperature change and the amplitude of the acoustic signal are directly related to the photon pulse energy.

Smith, T.J.; Frisch, J.C.; Kraft, E.M.; Loos, J.; /SLAC; Bentsen, G.S.; /Rochester U.

2011-12-13T23:59:59.000Z

452

Optics for X-Ray Laser and Laser Plasma Soft X-Ray Radiation  

Science Journals Connector (OSTI)

Focusing X-ray grazing incidence optics for X-ray laser and laser plasma soft X-ray radiation has been studied. ... computer code. Parabolic axisymmetric mirror for focusing Princeton X-ray laser beam and ellipso...

L. Pina; A. Inneman; R. Hudec

1996-01-01T23:59:59.000Z

453

Structure Analyses of Artificial Methane Hydrate Sediments by Microfocus X-ray Computed Tomography  

Science Journals Connector (OSTI)

The structure of natural gas hydrate sediments was characterized by microfocus X-ray computed tomography (CT). The obtained two-dimensional (2-D) and three-dimensional (3-D) images clearly showed the spatial distribution of the free-gas spaces, sand particles, and hydrates or ices. The estimated porosity from the X-ray CT data was consistent with the value that was obtained from the sample mass and volume. These results indicate that microfocus X-ray CT can be very useful for researching natural samples of hydrate sediments.

Shigeki Jin; Satoshi Takeya; Junko Hayashi; Jiro Nagao; Yasushi Kamata; Takao Ebinuma; Hideo Narita

2004-01-01T23:59:59.000Z

454

Moduli dispersion and attenuation in limestones in the laboratory L. Adam and M. Batzle, Center for Rock Abuse, Colorado School of Mines  

E-Print Network (OSTI)

variations in the intrinsic attenuation as a function of fluid content, and rock permeability at reservoir is common practice in reservoir rock physics. With knowl- edge of these properties, enhanced oil recovery transmitted through the rock core. We investigate the relation of permeability to attenuation, as well

455

An investigation of 3.2-cm attenuation by subtropical precipitation through use of a dual-frequency, equi-volume radar system  

E-Print Network (OSTI)

of radar attenuation are [29:58]: (I) absorption of energy by atmospheric gases and (2) absorption or scattering of energy by hydro- meteors;. Attenuation b atmos heric ases. --Water vapor and oxygen are the only atmospheric gases that cause signifi...

Hodges, Donald Bartholomew

1966-01-01T23:59:59.000Z

456

Seasonal variability in the vertical attenuation coefficient at 490 nm (K490) in waters around Puerto Rico and US Virgin Islands.  

E-Print Network (OSTI)

ecosystems. KEYWORDS: Water Diffuse Attenuation Coefficient, Kd, Remote Sensing, Ocean Color, Puerto Rico, US this affected sediment resuspension, intense water column mixing, and increased delivery of terrestrialSeasonal variability in the vertical attenuation coefficient at 490 nm (K490) in waters around

Gilbes, Fernando

457

Swift Pointing and the Association Between Gamma-Ray Bursts and Gravitational-Wave Bursts  

E-Print Network (OSTI)

The currently accepted model for gamma-ray burst phenomena involves the violent formation of a rapidly rotating solar mass black hole. Gravitational waves should be associated with the black-hole formation, and their detection would permit this model to be tested, the black hole progenitor (e.g., coalescing binary or collapsing stellar core) identified, and the origin of the gamma rays (within the expanding relativistic fireball or at the point of impact on the interstellar medium) located. Even upper limits on the gravitational-wave strength associated with gamma-ray bursts could constrain the gamma-ray burst model. To do any of these requires joint observations of gamma-ray burst events with gravitational and gamma-ray detectors. Here we examine how the quality of an upper limit on the gravitational-wave strength associated with gamma-ray burst observations depends on the relative orientation of the gamma-ray-burst and gravitational-wave detectors, and apply our results to the particular case of the Swift Burst-Alert Telescope (BAT) and the LIGO gravitational-wave detectors. A result of this investigation is a science-based ``figure of merit'' that can be used, together with other mission constraints, to optimize the pointing of the Swift telescope for the detection of gravitational waves associated with gamma-ray bursts.

Lee Samuel Finn; Badri Krishnan; Patrick J. Sutton

2003-04-11T23:59:59.000Z

458

Chip-Scale Quadrupole Mass Filters for Portable Mass Spectrometry  

E-Print Network (OSTI)

We report the design, fabrication, and characterization of a new class of chip-scale quadrupole mass filter (QMF). The devices are completely batch fabricated using a wafer-scale process that integrates the quadrupole ...

Cheung, Kerry

459

GIANT X-RAY BUMP IN GRB 121027A: EVIDENCE FOR FALL-BACK DISK ACCRETION  

SciTech Connect

A particularly interesting discovery in observations of GRB 121027A is that of a giant X-ray bump detected by the Swift/X-Ray Telescope. The X-ray afterglow re-brightens sharply at {approx}10{sup 3} s after the trigger by more than two orders of magnitude in less than 200 s. This X-ray bump lasts for more than 10{sup 4} s. It is quite different from typical X-ray flares. In this Letter we propose a fall-back accretion model to interpret this X-ray bump within the context of the collapse of a massive star for a long-duration gamma-ray burst. The required fall-back radius of {approx}3.5 Multiplication-Sign 10{sup 10} cm and mass of {approx}0.9-2.6 M{sub Sun} imply that a significant part of the helium envelope should survive through the mass loss during the last stage of the massive progenitor of GRB 121027A.

Wu Xuefeng [Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008 (China); Hou Shujin [Department of Astronomy and Institute of Theoretical Physics and Astrophysics, Xiamen University, Xiamen, Fujian 361005 (China); Lei Weihua, E-mail: xfwu@pmo.ac.cn, E-mail: leiwh@hust.edu.cn [School of Physics, Huazhong University of Science and Technology, Wuhan 430074 (China)

2013-04-20T23:59:59.000Z

460

Modeling the natural attenuation of benzene in groundwater impacted by ethanol-blended fuels: Effect of ethanol content  

E-Print Network (OSTI)

Modeling the natural attenuation of benzene in groundwater impacted by ethanol-blended fuels: Effect of ethanol content on the lifespan and maximum length of benzene plumes Diego E. Gomez1 and Pedro 10 March 2009. [1] A numerical model was used to evaluate how the concentration of ethanol

Alvarez, Pedro J.

Note: This page contains sample records for the topic "ray mass attenuation" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


461

Sorption-caused attenuation and delay of water-vapor signals in eddy-covariance sampling tubes and filters  

Science Journals Connector (OSTI)

Adsorption and desorption (together sorption) processes in sampling tubes and filters of eddy-covariance stations cause attenuation and delay of water-vapor signals, leading to underestimation of water-vapor fluxes by tens of per cent. The aim of ...

Annika Nordbo; Pekka Kekäläinen; Erkki Siivola; Ivan Mammarella; Jussi Timonen; Timo Vesala

462

Frequency dependent elastic properties and attenuation in heavy-oil sands: comparison between mea-sured and modeled data  

E-Print Network (OSTI)

Frequency dependent elastic properties and attenuation in heavy-oil sands: comparison between mea) properties of heavy-oil sands over a range of frequencies (2 - 2000Hz) covering the seismic bandwidth and at ultrasonic frequencies (0.8MHz). The measurements were carried on heavy-oil sand sample from Asphalt Ridge

463

The investigation of the nature and extent of attenuation of 3.2-cm radiation by subtropical precipitation  

E-Print Network (OSTI)

. " The relationship between Q and Q , the total scattering cross section, and Q s7 the total absorption cross section, is given by Qt = Qa + Qs (20) Attenuation b Atmos heric Gases Tnis study is concerned only with those gases which occur in abundance...

Patton, Robert Waldemar

1965-01-01T23:59:59.000Z

464

Atlas-based attenuation correction for small animal PET/MRI scanners Abhijit J. Chaudhari, ajchaudhari@ucdavis.edu,  

E-Print Network (OSTI)

Atlas-based attenuation correction for small animal PET/MRI scanners 1 Abhijit J. Chaudhari densities and not on electron densities. We propose a deformable mouse atlas-based registration method for AC in small animal PET/MRI. In this method, we first match the posture of the atlas to the posture

Leahy, Richard M.

465

Persistent Source Influences on the Trailing Edge of a Groundwater Plume, and Natural Attenuation Timeframes: The F-Area Savannah  

E-Print Network (OSTI)

number of deep boreholes were drilled to determine the current plume characteristics. A mixing model attenuation timeframes. INTRODUCTION Past disposal of large volumes of wastewaters at mining, weapons, Pb, Cd, Cr, and As. Large quantities of HNO3 and NaOH were also discharged into the basins

Hubbard, Susan

466

LeS D.4 Monitored Natural Attenuation -3 ENA OF HETEROCYCLIC HYDROCARBONS BY ADDING HYDROGEN PEROXIDE IN GROUND-  

E-Print Network (OSTI)

PEROXIDE IN GROUND- WATER CIRCULATION WELLS - A FIELD-BASED STUDY ON A LARGE PHYSICAL MODEL SCALE - Oliver natural attenuation) remediation strate- gies, it was found that most NSO-HET are highly mobile due to their high water solubility and low bio- degradation rates. In addition, some were found to be highly toxic

Cirpka, Olaf Arie

467

Accepted to SPIE DSS Conference April 29-May 3, 2013, Baltimore, MD Terahertz atmospheric attenuation and continuum effects  

E-Print Network (OSTI)

Terahertz atmospheric attenuation and continuum effects David M. Slocum,*a Thomas M. Goyette,a Elizabeth J interest in the terahertz frequency region. Applications such as pollution monitoring and detection of energetic chemicals are of particular interest. Although there has been much attention to atmospheric

Massachusetts at Lowell, University of

468

The Birmingham-CfA cluster scaling project - II. Mass composition and distribution  

E-Print Network (OSTI)

We investigate the spatial distribution of the baryonic and non-baryonic mass components in a sample of 66 virialized systems. We have used X-ray measurements to determine the deprojected temperature and density structure of the intergalactic medium and have employed these to map the underlying gravitational potential. In addition, we have measured the deprojected spatial distribution of galaxy luminosity for a subset of this sample, spanning over 2 decades in mass. With this combined X-ray/optical study we examine the scaling properties of the baryons and address the issue of mass-to-light (M/L) ratio in groups and clusters of galaxies. We measure a median mass-to-light ratio of 224 h70 M/L (solar) in the rest frame B_j band, in good agreement with other measurements based on X-ray determined masses. There is no trend in M/L with X-ray temperature and no significant trend for mass to increase faster than luminosity: M \\propto \\L_{B,j}^{1.08 +/- 0.12}. This implied lack of significant variation in star formation efficiency suggests that gas cooling cannot be greatly enhanced in groups, unless it drops out to form baryonic dark matter. Correspondingly, our results indicate that non-gravitational heating must have played a significant role in establishing the observed departure from self-similarity in low mass systems. The median baryon fraction for our sample is 0.162 h70^{-3/2}, which allows us to place an upper limit on the cosmological matter density, Omega_m <= 0.27 h70^{-1}, in good agreement with the latest results from WMAP. We find evidence of a systematic trend towards higher central density concentration in the coolest haloes, indicative of an early formation epoch and consistent with hierarchical formation models.

A. J. R. Sanderson; T. J. Ponman

2003-07-25T23:59:59.000Z

469

X-ray Stacking 2008-Apr-22 Astrostats X-ray Stacking  

E-Print Network (OSTI)

X-ray Stacking 2008-Apr-22 Astrostats X-ray Stacking Tom Aldcroft SAO/CXC #12;X-ray Stacking 2008 analysis for a sample Stacking ­ mean properties of sample Chandra X-ray data (faint point sources) are photon-limited with low background => stacking in X-rays is very effective #12;X-ray Stacking 2008-Apr-22

Wolfe, Patrick J.

470

Studying Gamma Ray Bursts from a  

E-Print Network (OSTI)

Studying Gamma Ray Bursts from a new perspective! {... Unraveling some mysteries and adding new Radio Op0cal X-ray Short ( energy -ray photons... ... accompained by a considerable long las0ng emission

Â?umer, Slobodan

471

SMB, X-Ray Spectroscopy & Imaging  

NLE Websites -- All DOE Office Websites (Extended Search)

Home X-Ray Spectroscopy & Imaging X-Ray Spectroscopy & Imaging SSRL has five hard X-ray Spectroscopy beamlines and three Microfocus Imaging beamlines dedicated to Biological and...

472

Lensless X-Ray Imaging in Reflection  

NLE Websites -- All DOE Office Websites (Extended Search)

Lensless X-Ray Imaging in Reflection Lensless X-Ray Imaging in Reflection Print Wednesday, 26 October 2011 00:00 The advent of x-ray free-electron laser (XFEL) light sources has...

473

Neutrino masses, leptogenesis, and sterile neutrino dark matter  

E-Print Network (OSTI)

We analyze a scenario in which the lightest heavy neutrino $N_1$ is a dark matter candidate and the second- heaviest neutrino $N_2$ decays producing a lepton number. If $N_1$ were in thermal equilibrium, its energy density today would be much larger than that of the observed dark matter, so we consider energy injection by the decay of $N_2$. In this paper, we show the parameters of this scenario that give the correct abundances of dark matter and baryonic matter and also induce the observed neutrino masses. This model can explain a possible sterile neutrino dark matter signal of $M_1$=7 keV in the x-ray observation of x-ray multi-mirror mission.

Takanao Tsuyuki

2014-07-20T23:59:59.000Z

474

Energetic particles and coronal mass ejections in the high latitude heliosphere: Ulysses-LET observations  

SciTech Connect

We have investigated energetic ions of non-corotating nature in the high latitude heliosphere. Major particle events were observed by Ulysses up to latitudes of 60 deg. S. All were associated with passage of coronal mass ejections (CMEs) over the spacecraft. The relationship of these events with solar activity was investigated using Yohkoh soft X-ray images.

Bothmer, V.; Marsden, R. G.; Sanderson, T. R.; Trattner, K. J.; Wenzel, K.-P.; Balogh, A.; Forsyth, R. J.; Goldstein, B. E.; Uchida, Y.; Hudson, H. S. [Space Science Department of ESA, ESTEC, Noordwijk (Netherlands); Blackett Laboratory, Imperial College, London (United Kingdom); Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California (United States); Physics Department, Science University, Tokyo (Japan); Institute for Astronomy, University of Hawaii, Honolulu, Hawaii (United States)

1996-07-20T23:59:59.000Z

475

Center for X-Ray Optics, 1992  

SciTech Connect

This report discusses the following topics: Center for X-Ray Optics; Soft X-Ray Imaging wit Zone Plate Lenses; Biological X-Ray microscopy; Extreme Ultraviolet Lithography for Nanoelectronic Pattern Transfer; Multilayer Reflective Optics; EUV/Soft X-ray Reflectometer; Photoemission Microscopy with Reflective Optics; Spectroscopy with Soft X-Rays; Hard X-Ray Microprobe; Coronary Angiography; and Atomic Scattering Factors.

Not Available

1993-08-01T23:59:59.000Z

476

Fiber fed x-ray/gamma ray imaging apparatus  

DOE Patents (OSTI)

X-ray/gamma ray imaging apparatus is disclosed for detecting the position, energy, and intensity of x-ray/gamma ray radiation comprising scintillation means disposed in the path of such radiation and capable of generating photons in response to such radiation; first photodetection means optically bonded to the scintillation means and capable of generating an electrical signal indicative of the intensity, and energy of the radiation detected by the scintillation means; second photodetection means capable of generating an electrical signal indicative of the position of the radiation in the radiation pattern; and means for optically coupling the scintillation means to the second photodetection means. The photodetection means are electrically connected to control and storage means which may also be used to screen out noise by rejecting a signal from one photodetection means not synchronized to a signal from the other photodetection means; and also to screen out signals from scattered radiation.

Hailey, Charles J. (San Francisco, CA); Ziock, Klaus-Peter (Livermore, CA)

1992-01-01T23:59:59.000Z

477

A CHANDRA X-RAY SURVEY OF EJECTA IN THE CASSIOPEIA A SUPERNOVA REMNANT  

SciTech Connect

We present a survey of the X-ray-emitting ejecta in the Cassiopeia A supernova remnant (SNR) based on an extensive analysis of over 6000 spectral regions extracted on 2.''5-10'' angular scales using the Chandra 1 Ms observation. We interpret these results in the context of hydrodynamical models for the evolution of the remnant. The distributions of fitted temperature and ionization age, and the implied mass coordinates, are highly peaked and suggest that the ejecta were subjected to multiple secondary shocks following reverse shock interaction with ejecta inhomogeneities. Based on the fitted emission measure and element abundances, and an estimate of the emitting volume, we derive masses for the X-ray-emitting ejecta and also show the distribution of the mass of various elements over the remnant. An upper limit to the total shocked Fe mass visible in X-rays appears to be roughly 0.13 M{sub Sun }, which accounts for nearly all of the mass expected in Fe ejecta. We find two populations of Fe ejecta, that associated with normal Si burning and that possibly associated with {alpha}-rich freezeout, with a mass ratio of approximately 2:1. Essentially all of the observed Fe (both components) lies well outside the central regions of the SNR, possibly having been ejected by hydrodynamic instabilities during the explosion. We discuss this and its implications for the neutron star kick.

Hwang, Una [Goddard Space Flight Center, Greenbelt, MD (United States); Laming, J. Martin, E-mail: Una.Hwang-1@gsfc.nasa.gov, E-mail: laming@nrl.navy.mil [Naval Research Laboratory, Code 7674L, Washington, DC 20375 (United States)

2012-02-20T23:59:59.000Z

478

Center for X-Ray Optics, 1991  

SciTech Connect

This report discusses: Soft-X-Ray imaging with zone-plate lenses; multilayer reflective optics; and spectroscopy with x-rays.

Not Available

1992-03-01T23:59:59.000Z

479

Ray Smith | Y-12 National Security Complex  

NLE Websites -- All DOE Office Websites (Extended Search)

Ray Smith Ray Smith Oral History Videos Speakers INTRODUCTION Ed Bailey Jim Bailey Kay Bailey Ken Bernander Willard Brock Wilma Brooks Elmer Brummitt Naomi Brummitt Blake Case...

480

SMB, X-ray Absorption Spectroscopy  

NLE Websites -- All DOE Office Websites (Extended Search)

Absorption Spectroscopy X-ray Absorption Spectroscopy X-ray absorption spectroscopy (XAS) is a well-established technique for simultaneous local geometric and electronic structure...

Note: This page contains sample records for the topic "ray mass attenuation" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


481

COMPACT BINARY PROGENITORS OF SHORT GAMMA-RAY BURSTS  

SciTech Connect

In recent years, detailed observations and accurate numerical simulations have provided support to the idea that mergers of compact binaries containing either two neutron stars (NSs) or an NS and a black hole (BH) may constitute the central engine of short gamma-ray bursts (SGRBs). The merger of such compact binaries is expected to lead to the production of a spinning BH surrounded by an accreting torus. Several mechanisms can extract energy from this system and power the SGRBs. Here we connect observations and numerical simulations of compact binary mergers, and use the current sample of SGRBs with measured energies to constrain the mass of their powering tori. By comparing the masses of the tori with the results of fully general-relativistic simulations, we are able to infer the properties of the binary progenitors that yield SGRBs. By assuming a constant efficiency in converting torus mass into jet energy, {epsilon}{sub jet} = 10%, we find that most of the tori have masses smaller than 0.01 M{sub Sun }, favoring 'high-mass' binary NSs mergers, i.e., binaries with total masses {approx}> 1.5 the maximum mass of an isolated NS. This has important consequences for the gravitational wave signals that may be detected in association with SGRBs, since 'high-mass' systems do not form a long-lived hypermassive NS after the merger. While NS-BH systems cannot be excluded to be the engine of at least some of the SGRBs, the BH would need to have an initial spin of {approx}0.9 or higher.

Giacomazzo, Bruno [JILA, University of Colorado and National Institute of Standards and Technology, Boulder, CO 80309 (United States); Perna, Rosalba [JILA and Department of Astrophysical and Planetary Sciences, University of Colorado, Boulder, CO 80309 (United States); Rezzolla, Luciano [Max-Planck-Institut fuer Gravitationsphysik, Albert-Einstein-Institut, Potsdam D-14476 (Germany); Troja, Eleonora [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Lazzati, Davide [Department of Physics, NC State University, 2401 Stinson Drive, Raleigh, NC 27695-8202 (United States)

2013-01-10T23:59:59.000Z

482

IRAQ'S WEAPONS OF MASS DESTRUCTION  

Science Journals Connector (OSTI)

DESPITE SEVEN YEARS OF INtrusive United Nations inspections and decimation of Iraq's weapons of mass destruction, Iraq was able to sequester sizable stocks of chemical and biological weapons, some missiles to deliver them, and the scientific and technical ...

LOIS EMBER

2002-09-16T23:59:59.000Z

483

Coulomb Resummation and Monopole Masses  

E-Print Network (OSTI)

The relativistic Coulomb resummation factor suggested by I.L. Solovtsov is used to reanalyze the mass limits obtained for magnetic monopoles which might have been produced at the Fermilab Tevatron. The limits given by the Oklahoma experiment (Fermilab E882) are pushed close to the unitary bounds, so that the lower limits on monopole masses are increased from around 250 GeV to about 400 GeV.

K. A. Milton

2008-02-18T23:59:59.000Z

484

Mass Quantization and Lepton Theory  

Science Journals Connector (OSTI)

This article discusses some features of mass quantization obtained by the introduction of a continuous inner degree of freedom into a free field. The usual particle interpretation, with discrete mass values, is applicable, as shown in the case of a second-quantized scalar field. A simple class of fermion field equations with unexpected lepton-like properties is also presented and studied in some detail.

Marcel Wellner

1962-03-01T23:59:59.000Z

485

X-ray Dip Monitoring of XB 1916-053  

E-Print Network (OSTI)

We report on the long term monitoring of X-ray dips from the ultracompact low-mass X-ray binary (LMXB) XB 1916-053. Roughly one-month interval observations were carried out with the Rossi X-ray Timing Explorer (RXTE) during 1996, during which the source varied between dim, hard states and more luminous, soft states. The dip spectra and dip lightcurves were compared against both the broadband luminosity and the derived mass accretion rate Mdot. The dips spectra could be fitted by an absorbed blackbody plus cut-off power law non-dip spectral model, with additional absorption ranging from 0 to >100 x 10^22 cm^-2. The amount of additional blackbody absorption was found to vary with the source luminosity. Our results are consistent with an obscuration of the inner disk region by a partially ionized outer disk. The size of the corona, derived from the dip ingress times, was found to be ~10^9 cm. The corona size did not correlate with the coronal temperature, but seemed to increase when \\Mdot also increased. We discuss our findings in the context of an evaporated accretion disk corona model and an ADAF-type model.

T. Narita; J. E. Grindlay; P. F. Bloser; Y. Chou

2003-05-06T23:59:59.000Z

486

X-ray Imaging Workshop  

NLE Websites -- All DOE Office Websites (Extended Search)

Imaging and Spectro-microscopy: Imaging and Spectro-microscopy: the Present and the Future Stanford Synchrotron Radiation Laboratory October 8-9, 2002 Organizers: John Miao & Keith Hodgson A workshop on "X-ray Imaging and Spectro-microscopy: the Present and the Future" was held on October 8-9, 2002. This workshop, organized by John Miao (SSRL) and Keith Hodgson (SSRL) provided a forum to discuss the scientific applications of a variety of imaging and spectro-microscopic techniques, including photoemission electron microscopy (PEEM), angle resolved photoemission spectroscopy (ARPES), coherent diffraction imaging, x-ray microscopy, micro-tomography, holographic imaging, and x-ray micro-probe. Twelve invited speakers discussed the important scientific applications of these techniques, and also predicted the future scientific directions with the advance of instrumentation and x-ray sources. The workshop was well attended with over fifty registered attendees.