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1

On the information content of the matter power spectrum  

E-Print Network (OSTI)

We discuss an analytical approximation for the matter power spectrum covariance matrix and its inverse on translinear scales, $k \\sim 0.1h - 0.8h/\\textrm{Mpc}$ at $z = 0$. We proceed to give an analytical expression for the Fisher information matrix of the nonlinear density field spectrum, and derive implications for its cosmological information content. We find that the spectrum information is characterized by a pair of upper bounds, 'plateaux', caused by the trispectrum, and a 'knee' in the presence of white noise. The effective number of Fourier modes, normally growing as a power law, is bounded from above by these plateaux, explaining naturally earlier findings from $N$-body simulations. These plateaux limit best possible measurements of the nonlinear power at the percent level in a $h^{-3}\\textrm{Gpc}^3$ volume; the extraction of model parameters from the spectrum is limited explicitly by their degeneracy to the nonlinear amplitude. The value of the first, super-survey (SS) plateau depends on the charact...

Carron, Julien; Szapudi, István

2014-01-01T23:59:59.000Z

2

Information content of the non-linear matter power spectrum  

E-Print Network (OSTI)

We use an ensemble of N-body simulations of the currently favoured (concordance) cosmological model to measure the amount of information contained in the non-linear matter power spectrum about the amplitude of the initial power spectrum. Two surprising results emerge from this study: (i) that there is very little independent information in the power spectrum in the translinear regime (k ~ 0.2-0.8 Mpc/h at the present day) over and above the information at linear scales and (ii) that the cumulative information begins to rise sharply again with increasing wavenumber in the non-linear regime. In the fully non-linear regime, the simulations are consistent with no loss of information during translinear and non-linear evolution. If this is indeed the case then the results suggest a picture in which translinear collapse is very rapid, and is followed by a bounce prior to virialization, impelling a wholesale revision of the HKLM-PD formalism.

C. D. Rimes; A. J. S. Hamilton

2005-02-03T23:59:59.000Z

3

Unscreening modified gravity in the matter power spectrum  

E-Print Network (OSTI)

Viable modifications of gravity that may produce cosmic acceleration need to be screened in high-density regions such as the Solar System, where general relativity is well tested. Screening mechanisms also prevent strong anomalies in the large-scale structure and limit the constraints that can be inferred on these gravity models from cosmology. We find that by suppressing the contribution of the screened high-density regions in the matter power spectrum, allowing a greater contribution of unscreened low densities, modified gravity models can be more readily discriminated from the concordance cosmology. Moreover, by variation of density thresholds, degeneracies with other effects may be dealt with more adequately. Specializing to chameleon gravity as a worked example for screening in modified gravity, employing N-body simulations of f(R) models and the halo model of chameleon theories, we demonstrate the effectiveness of this method. We find that a percent-level measurement of the clipped power at k Solar System tests or distance indicators in unscreened dwarf galaxies.

Lucas Lombriser; Fergus Simpson; Alexander Mead

2015-01-20T23:59:59.000Z

4

Unscreening modified gravity in the matter power spectrum  

E-Print Network (OSTI)

Viable modifications of gravity that may produce cosmic acceleration need to be screened in high-density regions such as the Solar System, where general relativity is well tested. Screening mechanisms also prevent strong anomalies in the large-scale structure and limit the constraints that can be inferred on these gravity models from cosmology. We find that by suppressing the contribution of the screened high-density regions in the matter power spectrum, allowing a greater contribution of unscreened low densities, modified gravity models can be more readily discriminated from the concordance cosmology. Moreover, by variation of density thresholds, degeneracies with other effects may be dealt with more adequately. Specializing to chameleon gravity as a worked example for screening in modified gravity, employing N-body simulations of f(R) models and the halo model of chameleon theories, we demonstrate the effectiveness of this method. We find that a percent-level measurement of the clipped power at k < 0.3 h...

Lombriser, Lucas; Mead, Alexander

2015-01-01T23:59:59.000Z

5

Steps toward the power spectrum of matter. I.The mean spectrum of galaxies  

E-Print Network (OSTI)

We calculate the mean power spectrum of galaxies using published power spectra of galaxies and clusters of galaxies. On small scales we use the power spectrum derived from the 2-dimensional distribution of APM galaxies, on large scales we use power spectra derived from 3-dimensional data for galaxy and cluster samples. Spectra are reduced to real space and to the amplitude of the power spectrum of APM galaxies. Available data indicate the presence of two different populations in the nearby Universe. Clusters of galaxies sample a relatively large region in the Universe where rich, medium and poor superclusters are well represented. Their mean power spectrum has a spike on scale 120 h^{-1}Mpc, followed by an approximate power-law spectrum of index n = -1.9 towards small scales. The power spectrum found from LCRS and IRAS 1.2 Jy surveys is flatter around the maximum, which may represent regions of the Universe with medium-rich and poor superclusters.

J. Einasto; M. Einasto; E. Tago; A. A. Starobinsky; F. Atrio-Barandela; V. M"uller; A. Knebe; P. Frisch; R. Cen; H. Andernach; D. Tucker

1998-12-13T23:59:59.000Z

6

Retrieving the 3D matter power spectrum and galaxy biasing parameters from lensing tomography  

E-Print Network (OSTI)

With the availability of galaxy distance indicators in weak lensing surveys, lensing tomography can basically be harnessed to constrain the spatial 3D matter power spectrum over a range in redshift and physical scale. Furthermore, by adding galaxy-galaxy lensing and galaxy clustering this can be extended to probe the 3D galaxy-matter and galaxy-galaxy power spectrum or, alternatively, galaxy biasing parameters. To achieve this aim, this paper introduces and discusses minimum variance estimators and a more general Bayesian approach to statistically invert a set of noisy tomography 2-point correlation functions, measured within a confined opening angle. Both methods are constructed such that they probe deviations of the 3D power spectrum from a fiducial power spectrum. Thereby a direct comparison of theory and data is achieved, the physical scale and redshift of deviations can in principle be identified. By devising a new Monte Carlo technique the measurement noise in the correlators is quantified for a fiducia...

Simon, Patrick

2012-01-01T23:59:59.000Z

7

Reproducing neutrino effects on the matter power spectrum through a degenerate Fermi gas approach  

E-Print Network (OSTI)

Modifications on the predictions about the matter power spectrum based on the hypothesis of a tiny contribution from a degenerate Fermi gas (DFG) test-fluid to some dominant cosmological scenario are investigated. Reporting about the systematic way of accounting for all the cosmological perturbations, through the Boltzmann equation we obtain the analytical results for density fluctuation, $\\delta$, and fluid velocity divergence, $\\theta$, of the DFG. Small contributions to the matter power spectrum are analytically obtained for the radiation-dominated background, through an ultra-relativistic approximation, and for the matter-dominated and $\\Lambda$-dominated eras, through a non-relativistic approximation. The results can be numerically reproduced and compared with those of considering non-relativistic and ultra-relativistic neutrinos into the computation of the matter power spectrum. Lessons concerning the formation of large scale structures of a DFG are depicted, and consequent deviations from standard $\\Lambda$CDM predictions for the matter power spectrum (with and without neutrinos) are quantified.

E. L. D. Perico; Alex E. Bernardini

2011-04-11T23:59:59.000Z

8

Newtonian Approach to the Matter Power Spectrum of the Generalized Chaplygin Gas  

E-Print Network (OSTI)

We model the cosmic medium as the mixture of a generalized Chaplygin gas and a pressureless matter component. Within a neo-Newtonian approach we compute the matter power spectrum. The 2dFGRS data are used to discriminate between unified models of the dark sector and different models, for which there is separate dark matter, in addition to that accounted for by the generalized Chaplygin gas. Leaving the corresponding density parameters free, we find that the unified models are strongly disfavored. On the other hand, using unified model priors, the observational data are also well described, in particular for small and large values of the generalized Chaplygin gas parameter $\\alpha$.

J. C. Fabris; S. V. B. Goncalves; H. E. S. Velten; W. Zimdahl

2008-11-14T23:59:59.000Z

9

Information content in the halo-model dark-matter power spectrum  

E-Print Network (OSTI)

Using the halo model, we investigate the cosmological Fisher information in the non-linear dark-matter power spectrum about the initial amplitude of linear power. We find that there is little information on `translinear' scales (where the one- and two-halo terms are both significant) beyond what is on linear scales, but that additional information is present on small scales, where the one-halo term dominates. This behavior agrees with the surprising results that Rimes & Hamilton (2005, 2006) found using N-body simulations. We argue that the translinear plateau in cumulative information arises largely from fluctuations in the numbers of large haloes in a finite volume. This implies that more information could be extracted on non-linear scales if the masses of the largest haloes in a survey are known.

Mark C. Neyrinck; István Szapudi; Christopher D. Rimes

2006-04-13T23:59:59.000Z

10

Matter Power Spectrum for the Generalized Chaplygin Gas Model: The Newtonian Approach  

E-Print Network (OSTI)

We model the cosmic medium as the mixture of a generalized Chaplygin gas and a pressureless matter component. Within a neo-Newtonian approach (in which, different from standard Newtonian cosmology, the pressure enters the homogeneous and isotropic background dynamics) we compute the matter power spectrum. The 2dFGRS data are used to discriminate between unified models of the dark sector (a purely baryonic matter component of roughly 5 percent of the total energy content and roughly 95 percent generalized Chaplygin gas) and different models, for which there is separate dark matter, in addition to that accounted for by the generalized Chaplygin gas. Leaving the corresponding density parameters free, we find that the unified models are strongly disfavored. On the other hand, using unified model priors, the observational data are also well described, in particular for small and large values of the generalized Chaplygin gas parameter $\\alpha$. The latter result is in agreement with a recent, more qualitative but fully relativistic, perturbation analysis in Gorini et al.

J. C. Fabris; S. V. B. Goncalves; H. E. S. Velten; W. Zimdahl

2008-10-23T23:59:59.000Z

11

The 2dF Galaxy Redshift Survey: The power spectrum and the matter content of the universe  

E-Print Network (OSTI)

The 2dF Galaxy Redshift Survey has now measured in excess of 160000 galaxy redshifts. This paper presents the power spectrum of the galaxy distribution, calculated using a direct FFT-based technique. We argue that, within the k-space region 0.02spectrum should be close to that of the linear density perturbations convolved with the window function of the survey. This window function and its convolving effect on the power spectrum estimate are analyzed in detail. By convolving model spectra, we are able to fit the power-spectrum data and provide a measure of the matter content of the universe. Our results show that models containing baryon oscillations are mildly preferred over featureless power spectra. Analysis of the data yields 68% confidence limits on the total matter density times the Hubble parameter \\Omega_m h = 0.20 +/- 0.03, and the baryon fraction \\Omega_b/\\Omega_m = 0.15 +/- 0.07, assuming scale-invariant primordial fluctuations.

Will J. Percival; Carlton M. Baugh; Joss Bland-Hawthorn; Terry Bridges; Russell Cannon; Shaun Cole; Matthew Colless; Chris Collins; Warrick Couch; Gavin Dalton; Roberto De Propris; Simon P. Driver; George Efstathiou; Richard S. Ellis; Carlos S. Frenk; Karl Glazebrook; Carole Jackson; Ofer Lahav; Ian Lewis; Stuart Lumsden; Steve Maddox; Stephen Moody; Peder Norberg; John A. Peacock; Bruce A. Peterson; Will Sutherland; Keith Taylor

2001-05-15T23:59:59.000Z

12

Matter power spectrum for the generalized Chaplygin gas model: The relativistic case  

E-Print Network (OSTI)

The generalized Chaplygin gas (GCG) model is the prototype of a unified model of dark energy (DE) and dark matter (DM). It is characterized by equation-of-state (EoS) parameters $A$ and $\\alpha$. We use a statistical analysis of the 2dFGRS data to constrain these parameters. In particular, we find that very small (close to zero) and very large values ($\\alpha\\gg 1$) of the equation-of-state parameter $\\alpha$ are preferred. To test the validity of this type of unification of the dark sector we admit the existence of a separate DM component in addition to the Chaplygin gas and calculate the probability distribution for the fractional contributions of both components to the total energy density. This analysis favors a model for which the Universe is nearly entirely made up of the separate DM component with an almost negligible Chaplygin gas part. This confirms the results of a previous Newtonian analysis.

J. C. Fabris; H. E. S. Velten; W. Zimdahl

2010-01-22T23:59:59.000Z

13

Matter Power Spectrum Covariance Matrix from the DEUS-PUR {\\Lambda}CDM simulations: Mass Resolution and non-Gaussian Errors  

E-Print Network (OSTI)

The upcoming generation of galaxy surveys will probe the distribution of matter in the universe with unprecedented accuracy. Measurements of the matter power spectrum at different scales and redshifts will provide stringent constraints on the cosmological parameters. However, on non-linear scales this will require an accurate evaluation of the covariance matrix. Here, we compute the covariance matrix of the matter power spectrum for the concordance $\\Lambda$CDM cosmology from an ensemble of N-body simulations of the Dark Energy Universe Simulation - Parallel Universe Runs (DEUS-PUR). This consists of 12288 realizations of a $(656\\,h^{-1}\\,\\textrm{Mpc})^3$ simulation box with $256^3$ particles. We combine this set with an auxiliary sample of 96 simulations of the same volume with $1024^3$ particles to assess the impact of non-Gaussian uncertainties due to mass resolution effects. We find this to be an important source of systematic errors at high redshift and small intermediate scales. We introduce an empirica...

Blot, Linda; Alimi, Jean-Michel; Reverdy, Vincent; Rasera, Yann

2014-01-01T23:59:59.000Z

14

The angular power spectrum of NVSS radio galaxies  

E-Print Network (OSTI)

We measure the angular power spectrum of radio galaxies in the NRAO VLA Sky Survey (NVSS) using two independent methods: direct spherical harmonic analysis and maximum likelihood estimation. The results are consistent and can be understood using models for the spatial matter power spectrum and for the redshift distribution of radio galaxies at mJy flux-density levels. A good fit to the angular power spectrum can only be achieved if radio galaxies possess high bias with respect to mass fluctuations; by marginalizing over the other parameters of the model we derive a 68% confidence interval 1.53 radio galaxies and sigma_8 describes the normalization of the matter power spectrum. Our models indicate that the majority of the signal in the NVSS angular power spectrum is generated at low redshifts. Individual redshifts for the NVSS sources are thus required to alleviate projection effects and probe directly the matter power spectrum on large scales.

Chris Blake; Pedro G. Ferreira; Julian Borrill

2004-04-05T23:59:59.000Z

15

Studying 21cm power spectrum with one-point statistics  

E-Print Network (OSTI)

The redshifted 21cm line signal from neutral hydrogens is a promising tool to probe the cosmic dawn and the epoch of reionization (EoR). Ongoing and future low-frequency radio experiments are expected to detect its fluctuations, especially through the power spectrum. In this paper, we give a physical interpretation of the time evolution of the power spectrum of the 21cm brightness temperature fluctuations, which can be decomposed into dark matter density, spin temperature and neutral fraction of hydrogen fluctuations. From the one-point statistics of the fluctuations, such as variance and skewness, we find that the peaks and dips in the time evolution are deeply related to X-ray heating of the intergalactic gas, which controls the spin temperature. We suggest the skewness of the brightness temperature distribution is a key observable to identify the onset of X-ray heating.

Shimabukuro, Hayato; Takahashi, Keitaro; Yokoyama, Shuichiro; Ichiki, Kiyotomo

2014-01-01T23:59:59.000Z

16

Power Spectrum in Krein Space Quantization  

E-Print Network (OSTI)

The power spectrum of scalar field and space-time metric perturbations produced in the process of inflation of universe, have been presented in this paper by an alternative approach to field quantization namely, Krein space quantization [1,2]. Auxiliary negative norm states, the modes of which do not interact with the physical world, have been utilized in this method. Presence of negative norm states play the role of an automatic renormalization device for the theory.

M. Mohsenzadeh; S. Rouhani; M. V. Takook

2008-11-06T23:59:59.000Z

17

Power spectrum of the fluctuation of Chebyshev's prime counting function  

E-Print Network (OSTI)

The one-sided power spectrum of the fluctuation of Chebyshev's weighted prime counting function is numerically estimated based on samples of the fluctuating function of different sizes. The power spectrum is also estimated analytically for large frequency based on Riemann hypothesis and the exact formula for the fluctuating function in terms of all the non-trivial Riemann zeroes. Our analytical estimate is consistent with our numerical estimate of a 1/f^2 power spectrum.

Boon Leong Lan; Shaohen Yong

2005-06-20T23:59:59.000Z

18

The 21-cm power spectrum after reionization  

Science Journals Connector (OSTI)

......spectrum (PS) following the completion of reionization. In contrast...uncertainty in the primordial PS index or through a running spectral index, which we have not considered...the 21-cm PS following the completion of reionization. Our approach......

J. Stuart B. Wyithe; Abraham Loeb

2009-08-21T23:59:59.000Z

19

Power spectrum of electron number density perturbations at cosmological recombination epoch  

E-Print Network (OSTI)

The power spectrum of number density perturbations of free electrons is obtained for the epoch of cosmological recombination of hydrogen. It is shown that amplitude of the electron perturbations power spectrum of scales larger than acoustic horizon exceeds by factor of 17 the amplitude of baryon matter density ones (atoms and ions of hydrogen and helium). In the range of the first and second acoustic peaks such relation is 18, in the range of the third one 16. The dependence of such relations on cosmological parameters is analysed too.

B. Venhlovska; B. Novosyadlyj

2008-12-12T23:59:59.000Z

20

MEASURING THE JET POWER OF FLAT-SPECTRUM RADIO QUASARS  

SciTech Connect

We use frequency-dependent position shifts of flat-spectrum radio cores to estimate the kinetic power of active galactic nucleus (AGN) jets. We find a correlation between the derived jet powers and AGN narrow-line luminosity, consistent with the well-known relation for radio galaxies and steep spectrum quasars. This technique can be applied to intrinsically weak jets even at high redshift.

Shabala, S. S.; Santoso, J. S. [School of Mathematics and Physics, University of Tasmania, Private Bag 37, Hobart, TAS 7001 (Australia); Godfrey, L. E. H. [International Centre for Radio Astronomy Research, Curtin University, GPO Box U1987, Perth, Western Australia 6845 (Australia)

2012-09-10T23:59:59.000Z

Note: This page contains sample records for the topic "matter power spectrum" 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

The Cosmic Microwave Background: Beyond the Power Spectrum  

E-Print Network (OSTI)

Much recent work on the cosmic microwave background (CMB) has focussed on the angular power spectrum of temperature anisotropies and particularly on the recovery of cosmological parameters from acoustic peaks in the power spectrum. However, there is more that can conceivably be done with CMB measurements. Here I briefly survey a few such ideas: cross-correlation with other cosmic backgrounds as a probe of the density of the Universe; CMB polarization as a gravitational-wave detector; secondary anisotropies and the ionization history of the Universe; tests of alternative-gravity theories; polarization, the Sunyaev-Zeldovich effect, and cosmic variance; and tests for a neutrino mass.

Marc Kamionkowski

1998-09-24T23:59:59.000Z

22

Quantifying galactic propagation uncertainty in WIMP dark matter search with AMS01 Z=-1 spectrum  

E-Print Network (OSTI)

A search for a WIMP dark matter annihilation signal is carried out in the AMS01 negatively charged (Z=-I) particle spectrum, following a set of supersymmetric benchmark scenarios in the mSUGRA framework. The result is ...

Xiao, Sa, Ph. D. Massachusetts Institute of Technology

2009-01-01T23:59:59.000Z

23

SIC (MUltiple SIgnal Classification) CSP (Cross-power Spectrum Phase)  

E-Print Network (OSTI)

2ch CSP ( ) 1 MU- SIC (MUltiple SIgnal Classification) CSP (Cross- power Spectrum Phase) [1, 2, 3, 4] [5, 6] [7, 8, 9, 10] [7] CSP CSP [8] [9] CSP [10] Estimation of talker's head orientation based (Kobe univ.) [11] 2ch CSP CSP CSP CSP 2 CSP GCC-PHAT (Generalized Cross- Correlation PHAse Transform

Takiguchi, Tetsuya

24

Power Control in Spectrum Overlay Networks: How to Cross a Multi-Lane Highway  

E-Print Network (OSTI)

--Cognitive radio, opportunistic spectrum access, spec- trum overlay, power control, spectrum opportunity detectionPower Control in Spectrum Overlay Networks: How to Cross a Multi-Lane Highway Wei Ren, Qing Zhao in spectrum overlay networks (also referred to as opportunistic spectrum access) where secondary users

Islam, M. Saif

25

Reconstructing the linear power spectrum of cosmological mass fluctuations  

E-Print Network (OSTI)

We describe an attempt to reconstruct the initial conditions for the formation of cosmological large-scale structure. The power spectrum of the primordial fluctuations is affected by bias, nonlinear evolution and redshift-space distortions, but we show how these effects can be corrected for analytically. Using eight independent datasets, we obtain excellent agreement in the estimated linear power spectra given the following conditions. First, the relative bias factors for Abell clusters, radio galaxies, optical galaxies and IRAS galaxies must be in the ratios 4.5:1.9:1.3:1. Second, the data require redshift-space distortion: $\\Omega^{0.6}/b_{\\ss I} = 1.0 \\pm 0.2$. Third, low values of $\\Omega$ and bias are disfavoured. The shape of the spectrum is extremely well described by a CDM transfer function with an apparent value of the fitting parameter $\\Omega h =0.25$. Tilted models predict too little power at 100 Mpc wavelengths.

J. A. Peacock; S. J. Dodds

1993-11-23T23:59:59.000Z

26

Power spectrum normalization from the local abundance of rich clusters of galaxies  

E-Print Network (OSTI)

The number density of rich galaxy clusters still provides the most robust way of normalizing the power spectrum of dark matter perturbations on scales relevant to large-scale structure. We revisit this constraint in light of several recent developments: (1) the availability of well-defined samples of local clusters with relatively accurate X-ray temperatures; (2) new theoretical mass functions for dark matter haloes which provide a good fit to large numerical simulations; (3) more accurate mass-temperature relations from larger catalogs of hydrodynamical simulations; (4) the requirement to consider closed as well as open and flat cosmologies to obtain full multi-parameter likelihood constraints for CMB and SNe studies. We present a new sample of clusters drawn from the literature and use this sample to obtain improved results on sigma_8, the normalization of the matter power spectrum on scales of 8 h^{-1} Mpc, as a function of the matter density and cosmological constant in a Universe with general curvature. We discuss our differences with previous work, and the remaining major sources of uncertainty. Final results on the 68 per cent confidence region, approximately independent of power spectrum shape, can be expressed as constraints on sigma at an appropriate cluster normalization scale R_Cl. We provide fitting formulas for R_Cl and sigma(R_Cl) for general cosmologies, as well as for sigma_8 as a function of cosmology and shape parameter Gamma. For flat models we find approximately sigma_8 \\simeq 0.495^{+0.034}_{-0.037}) Omega_M^{-0.60} for Gamma=0.23, where the error bar is dominated by uncertainty in the mass-temperature relation.

E. Pierpaoli; D. Scott; M. White

2001-09-27T23:59:59.000Z

27

Single-Particle Spectrum of Pure Neutron Matter  

E-Print Network (OSTI)

We have calculated the self-consistent auxiliary potential effects on the binding energy of neutron matter using the Brueckner Hartree Fock approach by adopting the Argonne V18 and CD-Bonn potentials. The binding energy with the four different choices for the self-consistent auxiliary potential is discussed. Also, the binding energy of neutron matter has been computed within the framework of the self-consistent Green s function approach. We also compare the binding energies obtained in this study with those obtained by various microscopic approaches.

Khalaf Gad; Hesham Mansour

2015-02-06T23:59:59.000Z

28

Contamination of Cluster Radio Sources in the Measurement of the Thermal Sunyaev-Zel'dovich Angular Power Spectrum  

E-Print Network (OSTI)

We present a quantitative estimate of the confusion of cluster radio halos and galaxies in the measurement of the angular power spectrum of the thermal Sunyaev-Zel'dovich (SZ) effect. To achieve the goal, we use a purely analytic approach to both radio sources and dark matter of clusters by incorporating empirical models and observational facts together with some theoretical considerations. It is shown that the correction of cluster radio halos and galaxies to the measurement of the thermal SZ angular power spectrum is no more than 20% at $l>2000$ for observing frequencies $\

Wei Zhou; Xiang-Ping Wu

2003-09-26T23:59:59.000Z

29

Reconstruction of the Primordial Power Spectrum by Direct Inversion  

E-Print Network (OSTI)

We introduce a new method for reconstructing the primordial power spectrum, $P(k)$, directly from observations of the Cosmic Microwave Background (CMB). We employ Singular Value Decomposition (SVD) to invert the radiation perturbation transfer function. The degeneracy of the multipole $\\ell$ to wavenumber $k$ linear mapping is thus reduced. This enables the inversion to be carried out at each point along a Monte Carlo Markov Chain (MCMC) exploration of the combined $P(k)$ and cosmological parameter space. We present best--fit $P(k)$ obtained with this method along with other cosmological parameters.

Nicholson, Gavin; Paykari, Paniez

2009-01-01T23:59:59.000Z

30

Reconstructing the primordial power spectrum from the CMB  

SciTech Connect

We propose a straightforward and model independent methodology for characterizing the sensitivity of CMB and other experiments to wiggles, irregularities, and features in the primordial power spectrum. Assuming that the primordial cosmological perturbations are adiabatic, we present a function space generalization of the usual Fisher matrix formalism applied to a CMB experiment resembling Planck with and without ancillary data. This work is closely related to other work on recovering the inflationary potential and exploring specific models of non-minimal, or perhaps baroque, primordial power spectra. The approach adopted here, however, most directly expresses what the data is really telling us. We explore in detail the structure of the available information and quantify exactly what features can be reconstructed and at what statistical significance.

Gauthier, Christopher; Bucher, Martin, E-mail: cgauthie@apc.univ-paris7.fr, E-mail: bucher@apc.univ-paris7.fr [Laboratoire APC, Université Paris Diderot, Bâtiment Condorcet, 10 rue Alice Domon et Léonie Duquet, 75205 Paris Cedex 13 (France)

2012-10-01T23:59:59.000Z

31

BAYESIAN ANGULAR POWER SPECTRUM ANALYSIS OF INTERFEROMETRIC DATA  

SciTech Connect

We present a Bayesian angular power spectrum and signal map inference engine which can be adapted to interferometric observations of anisotropies in the cosmic microwave background (CMB), 21 cm emission line mapping of galactic brightness fluctuations, or 21 cm absorption line mapping of neutral hydrogen in the dark ages. The method uses Gibbs sampling to generate a sampled representation of the angular power spectrum posterior and the posterior of signal maps given a set of measured visibilities in the uv-plane. We use a mock interferometric CMB observation to demonstrate the validity of this method in the flat-sky approximation when adapted to take into account arbitrary coverage of the uv-plane, mode-mode correlations due to observations on a finite patch, and heteroschedastic visibility errors. The computational requirements scale as O(n{sub p} log n{sub p}) where n{sub p} measures the ratio of the size of the detector array to the inter-detector spacing, meaning that Gibbs sampling is a promising technique for meeting the data analysis requirements of future cosmology missions.

Sutter, P. M.; Wandelt, Benjamin D. [Department of Physics, 1110 West Green Street, University of Illinois at Urbana-Champaign, Urbana, IL 61801 (United States); Malu, Siddarth S. [Raman Research Institute, C V Raman Avenue, Bangalore 560080 (India)

2012-09-15T23:59:59.000Z

32

Imprints of deviations from the gravitational inverse-square law on the power spectrum of mass fluctuations  

E-Print Network (OSTI)

Deviations from the gravitational inverse-square law would imprint scale-dependent features on the power spectrum of mass density fluctuations. We model such deviations as a Yukawa-like contribution to the gravitational potential and discuss the growth function in a mixed dark matter model with adiabatic initial conditions. Evolution of perturbations is considered in general non-flat cosmological models with a cosmological constant, and an analytical approximation for the growth function is provided. The coupling between baryons and cold dark matter across recombination is negligibly affected by modified gravity physics if the proper cutoff length of the long-range Yukawa-like force is > 10 h^{-1} Mpc. Enhancement of gravity affects the subsequent evolution, boosting large-scale power in a way that resembles the effect of a lower matter density. This phenomenon is almost perfectly degenerate in power-spectrum shape with the effect of a background of massive neutrinos. Back-reaction on density growth from a modified cosmic expansion rate should however also affect the normalization of the power spectrum, with a shape distortion similar to the case of a non-modified background.

M. Sereno; J. A. Peacock

2006-05-19T23:59:59.000Z

33

Loops and spurs: the angular power spectrum of the Galactic synchrotron background  

SciTech Connect

We present a new model of the diffuse Galactic synchrotron radiation, concentrating on its angular anisotropies. While previous studies have focussed on either the variation of the emissivity on large ( ? kpc) scales, or on fluctuations due to MHD turbulence in the interstellar medium, we unify these approaches to match the angular power spectrum. We note that the usual turbulence cascade calculation ignores spatial correlations at the injection scale ( ? 100 pc) due to compression of the interstellar medium by of O(1000) old supernova remnants — the 'radio loops' only four of which are visible in radio maps. This new component naturally provides the otherwise missing power on intermediate and small scales in the all-sky map at 408 MHz. Our model can enable more reliable subtraction of the synchrotron foreground for studies of CMB anisotropies or searches for dark matter annihilation. We conclude with some remarks on the relevance to modelling of the polarised foreground.

Mertsch, Philipp [Kavli Institute for Particle Astrophysics and Cosmology, 2575 Sand Hill Road, M/S 29, Menlo Park, CA 94025 (United States); Sarkar, Subir, E-mail: pmertsch@stanford.edu, E-mail: sarkar@nbi.dk [Rudolf Peierls Centre for Theoretical Physics, University of Oxford, 1 Keble Road, Oxford OX1 3NP (United Kingdom)

2013-06-01T23:59:59.000Z

34

Constraining warm dark matter with cosmic shear power spectra  

SciTech Connect

We investigate potential constraints from cosmic shear on the dark matter particle mass, assuming all dark matter is made up of light thermal relic particles. Given the theoretical uncertainties involved in making cosmological predictions in such warm dark matter scenarios we use analytical fits to linear warm dark matter power spectra and compare (i) the halo model using a mass function evaluated from these linear power spectra and (ii) an analytical fit to the non-linear evolution of the linear power spectra. We optimistically ignore the competing effect of baryons for this work. We find approach (ii) to be conservative compared to approach (i). We evaluate cosmological constraints using these methods, marginalising over four other cosmological parameters. Using the more conservative method we find that a Euclid-like weak lensing survey together with constraints from the Planck cosmic microwave background mission primary anisotropies could achieve a lower limit on the particle mass of 2.5 keV.

Markovic, Katarina; Weller, Jochen [University Observatory Munich, Ludwig-Maximilian University, Scheinerstr. 1, 81679 Munich (Germany); Bridle, Sarah [Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT (United Kingdom); Slosar, Anže, E-mail: markovic@usm.lmu.de, E-mail: sarah.bridle@ucl.ac.uk, E-mail: anze@bnl.gov, E-mail: jochen.weller@usm.lmu.de [Brookhaven National Laboratory, Building 510A, Upton, NY 11973-5000 (United States)

2011-01-01T23:59:59.000Z

35

Efficient power spectrum estimation for high resolution CMB maps  

SciTech Connect

Estimation of the angular power spectrum of the cosmic microwave background on a small patch of sky is usually plagued by serious spectral leakage, especially when the map has a hard edge. Even on a full-sky map, point source masks can alias power from large scales to small scales producing excess variance at high multipoles. We describe a new fast, simple, and local method for estimation of power spectra on small patches of the sky that minimizes spectral leakage and reduces the variance of the spectral estimate. For example, when compared with the standard uniform sampling approach on a 8 deg. x 8 deg. patch of the sky with 2% area masked due to point sources, our estimator halves the error bars at l=2000 and achieves a more than fourfold reduction in error bars at l=3500. Thus, a properly analyzed experiment will have error bars at l=3500 equivalent to those of an experiment analyzed with the now standard technique with {approx}16-25 times the integration time.

Das, Sudeep; Hajian, Amir; Spergel, David N. [Department of Astrophysical Sciences, Princeton University, Princeton, New Jersey 08544 (United States)

2009-04-15T23:59:59.000Z

36

Combining power spectrum and bispectrum measurements to detect oscillatory features  

E-Print Network (OSTI)

The simplest inflationary models present us with few observable parameters to discriminate between them. A detection of features in the spectra of primordial density perturbations could provide valuable insights and lead to stringent tests of models of the early universe. So far, searches for oscillatory features have not produced statistically significant results. In this work we consider a combined search for features in the power spectrum and bispectrum. We show that possible dependencies between the estimates of feature model amplitudes based on the two and three-point correlators are largely statistically independent under the assumption of the null hypothesis of a nearly Gaussian featureless CMB. Building on this conclusion we propose an optimal amplitude estimator for a combined search and study the look-elsewhere effect in feature model surveys. In particular we construct analytic models for the distribution of amplitude estimates that allow for a reliable assessment of the significance of potential f...

Fergusson, J R; Shellard, E P S; Liguori, M

2014-01-01T23:59:59.000Z

37

Power and spectrum efficient communications in wireless ad hoc networks  

E-Print Network (OSTI)

Ephremides, “Joint Scheduling and Power Control for WirelessOptimal Power Control, Scheduling, and Routing in UWBDistributed Joint Scheduling and Power Control Algorithm for

Qu, Qi

2008-01-01T23:59:59.000Z

38

The Power Spectrum of Rich Clusters of Galaxies on Large Spatial Scales  

E-Print Network (OSTI)

We present an analysis of the redshift-space power spectrum, $P(k)$, of rich clusters of galaxies based on an automated cluster catalogue selected from the APM Galaxy Survey. We find that $P(k)$ can be approximated by a power law, $P(k)\\proptok^{n}$, with $n\\approx-1.6$ over the wavenumber range $0.04\\hrpower spectrum has the same shape as the power spectra measured for optical and IRAS galaxies. This is consistent with a simple linear bias model in which different tracers have the same power spectrum as that of the mass distribution but shifted in amplitude by a constant biasing factor. On larger scales, the power spectrum of APM clusters flattens and appears to turn over on a scale $k \\sim 0.03\\hmpcrev$. We compare the power spectra estimated from simulated APM cluster catalogues to those estimated directly from cubical N-body simulation volumes and find that the APM cluster survey should give reliable estimates of the true power spectrum at wavenumbers $k \\simgt 0.02\\hmpcrev$. These results suggest that the observed turn-over in the power spectrum may be a real feature of the cluster distribution and that we have detected the transition to a near scale-invariant power spectrum implied by observations of anisotropies in the cosmic microwave background radiation. The scale of the turn-over in the cluster power spectrum is in good agreement with the scale of the turn-over observed in the power spectrum of APM galaxies.

Helen Tadros; George Efstathiou; Gavin Dalton

1997-08-28T23:59:59.000Z

39

Does topological information matter for power grid vulnerability?  

Science Journals Connector (OSTI)

Power grids which are playing an important role in supporting the economy of a region as well as the life of its citizens could be attacked by terrorists or enemies to damage the region. Depending on different levels of power grid information collected by the terrorists their attack strategies might be different. This paper groups power grid information into four levels: no information purely topological information (PTI) topological information with generator and load nodes (GLNI) and full information (including component physical properties and flow parameters information) and then identifies possible attack strategies for each information level. Analyzing and comparing power grid vulnerability under these attack strategies from both terrorists' and utility companies' point of view give rise to an approach to quantify the relative values of these three types of information including PTI GLNI and component parameter information (CPI). This approach can provide information regarding the extent to which topological information matters for power system vulnerability decisions. Taking several test systems as examples results show that for small attacks with p ? ? ?0.1 CPI matters the most; when taking attack cost into consideration and assuming that the terrorists take the optimum cost-efficient attack intensity then CPI has the largest cost-based information value.

2014-01-01T23:59:59.000Z

40

The 2dF Galaxy Redshift Survey: Power-spectrum analysis of the final dataset and cosmological implications  

E-Print Network (OSTI)

We present a power spectrum analysis of the final 2dF Galaxy Redshift Survey, employing a direct Fourier method. The sample used comprises 221,414 galaxies with measured redshifts. We investigate in detail the modelling of the sample selection. A new angular mask is derived, based on revisions to the photometric calibration. The redshift selection function is determined by dividing the survey according to rest-frame colour, and deducing a self-consistent treatment of k-corrections and evolution for each population. The covariance matrix for the power-spectrum estimates is determined using two different approaches to the construction of mock surveys which are used to demonstrate that the input cosmological model can be correctly recovered. We are confident that the 2dFGRS power spectrum can be used to infer the matter content of the universe. On large scales, our estimated power spectrum shows evidence for the `baryon oscillations' that are predicted in CDM models. Fitting to a CDM model, assuming a primordial $n_{s}=1$ spectrum, $h=0.72$ and negligible neutrino mass, the preferred parameters are $\\Omega_{M} h = 0.168 \\pm 0.016$ and a baryon fraction $\\Omega_{b} /\\Omega_{M} = 0.185\\pm0.046$ (1$\\sigma$ errors). The value of $\\Omega_{M} h$ is $1\\sigma$ lower than the $0.20 \\pm 0.03$ in our 2001 analysis of the partially complete 2dFGRS. This shift is largely due to the signal from the newly-sampled regions of space, rather than the refinements in the treatment of observational selection. This analysis therefore implies a density significantly below the standard $\\Omega_{M} =0.3$: in combination with CMB data from WMAP, we infer $\\Omega_{M} =0.231\\pm 0.021$. (Abridged.)

S. Cole; W. J. Percival; J. A. Peacock; P. Norberg; C. M. Baugh; C. S. Frenk; I. Baldry; J. Bland-Hawthorn; T. Bridges; R. Cannon; M. Colless; C. Collins; W. Couch; N. J. G. Cross; G. Dalton; V. R. Eke; R. De Propris; S. P. Driver; G. Efstathiou; R. S. Ellis; K. Glazebrook; C. Jackson; A. Jenkins; O. Lahav; I. Lewis; S. Lumsden; S. Maddox; D. Madgwick; B. A. Peterson; W. Sutherland; K. Taylor

2005-08-05T23:59:59.000Z

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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
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41

Composite bosonic baryon dark matter on the lattice: SU(4) baryon spectrum and the effective Higgs interaction  

E-Print Network (OSTI)

We present the spectrum of baryons in a new SU(4) gauge theory with fundamental fermion constituents. The spectrum of these bosonic baryons is of significant interest for composite dark matter theories. Here, we compare the spectrum and properties of SU(3) and SU(4) baryons, and then compute the dark-matter direct detection cross section via Higgs boson exchange for TeV-scale composite dark matter arising from a confining SU(4) gauge sector. Comparison with the latest LUX results leads to tight bounds on the fraction of the constituent-fermion mass that may arise from electroweak symmetry breaking. Lattice calculations of the dark matter mass spectrum and the Higgs-dark matter coupling are performed on quenched $16^{3} \\times 32$, $32^{3} \\times 64$, $48^{3} \\times 96$, and $64^{3} \\times128$ lattices with three different lattice spacings, using Wilson fermions with moderate to heavy pseudoscalar meson masses. Our results lay a foundation for future analytic and numerical study of composite baryonic dark matter.

Thomas Appelquist; Evan Berkowitz; Richard C. Brower; Michael I. Buchoff; George T. Fleming; Joe Kiskis; Graham D. Kribs; Meifeng Lin; Ethan T. Neil; James C. Osborn; Claudio Rebbi; Enrico Rinaldi; David Schaich; Chris Schroeder; Sergey Syritsyn; Gennady Voronov; Pavlos Vranas; Evan Weinberg; Oliver Witzel

2014-02-26T23:59:59.000Z

42

Two dark matter components in dark matter extension of the minimal supersymmetric standard model and the high energy positron spectrum in PAMELA/HEAT data  

SciTech Connect

We present a dark matter extension of the minimal supersymmetric standard model to give the recent trend of the high energy positron spectrum of the PAMELA/HEAT experiments. If the trend is caused indeed by dark matter, the minimal supersymmetric standard model needs to be extended. Here, we minimally extend the minimal supersymmetric standard model with one more dark matter component N together with a heavy lepton E and introduce the coupling e{sub R}E{sub R}{sup c}N{sub R}. This coupling naturally appears in the flipped SU(5) grand unification models. We also present the needed parameter ranges of these additional particles.

Huh, Ji-Haeng; Kim, Jihn E.; Kyae, Bumseok [Department of Physics and Astronomy and Center for Theoretical Physics, Seoul National University, Seoul 151-747 (Korea, Republic of)

2009-03-15T23:59:59.000Z

43

Relationship between magnetic power spectrum and flare productivity in solar active regions  

E-Print Network (OSTI)

; Politano et al. 1989) energy spectrum of solar wind plasma is close to k-5/3 . In the MHD case, Alfven.I. Abramenko Big Bear Solar Observatory, 40386 N. Shore Lane, Big Bear City, CA 92314, USA ABSTRACT Power turbulent regime with constant rate of energy transfer along the spectrum is holding. Due to an equilibrium

44

The hybrid SZ power spectrum: Combining cluster counts and SZ fluctuations to probe gas physics  

E-Print Network (OSTI)

Sunyaev-Zeldovich (SZ) effect from a cosmological distribution of clusters carry information on the underlying cosmology as well as the cluster gas physics. In order to study either cosmology or clusters one needs to break the degeneracies between the two. We present a toy model showing how complementary informations from SZ power spectrum and the SZ flux counts, both obtained from upcoming SZ cluster surveys, can be used to mitigate the strong cosmological influence (especially that of sigma_8) on the SZ fluctuations. Once the strong dependence of the cluster SZ power spectrum on sigma_8 is diluted, the cluster power spectrum can be used as a tool in studying cluster gas structure and evolution. The method relies on the ability to write the Poisson contribution to the SZ power spectrum in terms the observed SZ flux counts. We test the toy model by applying the idea to simulations of SZ surveys.

J. M. Diego; Subhabrata Majumdar

2004-02-18T23:59:59.000Z

45

SIC (MUltiple SIgnal Classification) CSP (Cross-power Spectrum Phase)  

E-Print Network (OSTI)

, 6] [7, 8, 9, 10] [7] SRP-PHAT (Steered Response Power with the PHAse Transform) SRP-PHAT [8] [9] SRP

Takiguchi, Tetsuya

46

Solar gamma rays powered by secluded dark matter  

SciTech Connect

Secluded dark matter models, in which weakly interacting massive particles annihilate first into metastable mediators, can present novel indirect detection signatures in the form of gamma rays and fluxes of charged particles arriving from directions correlated with the centers of large astrophysical bodies within the Solar System, such as the Sun and larger planets. This naturally occurs if the mean free path of the mediator is in excess of the solar (or planetary) radius. We show that existing constraints from water Cerenkov detectors already provide a novel probe of the parameter space of these models, complementary to other sources, with significant scope for future improvement from high angular resolution gamma-ray telescopes such as Fermi-LAT. Fluxes of charged particles produced in mediator decays are also capable of contributing a significant solar system component to the spectrum of energetic electrons and positrons, a possibility which can be tested with the directional and timing information of PAMELA and Fermi.

Batell, Brian; Shang Yanwen [Perimeter Institute for Theoretical Physics, Waterloo, Ontario, N2J 2W9 (Canada); Pospelov, Maxim [Perimeter Institute for Theoretical Physics, Waterloo, Ontario, N2J 2W9 (Canada); Department of Physics and Astronomy, University of Victoria, Victoria, British Columbia, V8P 1A1 (Canada); Ritz, Adam [Department of Physics and Astronomy, University of Victoria, Victoria, British Columbia, V8P 1A1 (Canada)

2010-04-01T23:59:59.000Z

47

Primordial power spectrum: a complete analysis with the WMAP nine-year data  

SciTech Connect

We have improved further the error sensitive Richardson-Lucy deconvolution algorithm making it applicable directly on the un-binned measured angular power spectrum of Cosmic Microwave Background observations to reconstruct the form of the primordial power spectrum. This improvement makes the application of the method significantly more straight forward by removing some intermediate stages of analysis allowing a reconstruction of the primordial spectrum with higher efficiency and precision and with lower computational expenses. Applying the modified algorithm we fit the WMAP 9 year data using the optimized reconstructed form of the primordial spectrum with more than 300 improvement in ?{sup 2}{sub eff} with respect to the best fit power-law. This is clearly beyond the reach of other alternative approaches and reflects the efficiency of the proposed method in the reconstruction process and allow us to look for any possible feature in the primordial spectrum projected in the CMB data. Though the proposed method allow us to look at various possibilities for the form of the primordial spectrum, all having good fit to the data, proper error-analysis is needed to test for consistency of theoretical models since, along with possible physical artefacts, most of the features in the reconstructed spectrum might be arising from fitting noises in the CMB data. Reconstructed error-band for the form of the primordial spectrum using many realizations of the data, all bootstrapped and based on WMAP 9 year data, shows proper consistency of power-law form of the primordial spectrum with the WMAP 9 data at all wave numbers. Including WMAP polarization data in to the analysis have not improved much our results due to its low quality but we expect Planck data will allow us to make a full analysis on CMB observations on both temperature and polarization separately and in combination.

Hazra, Dhiraj Kumar; Shafieloo, Arman [Asia Pacific Center for Theoretical Physics, Pohang, Gyeongbuk 790-784 (Korea, Republic of); Souradeep, Tarun, E-mail: dhiraj@apctp.org, E-mail: arman@apctp.org, E-mail: tarun@iucaa.ernet.in [Inter-University Centre for Astronomy and Astrophysics, Post Bag 4, Ganeshkhind, Pune 411 007 (India)

2013-07-01T23:59:59.000Z

48

Climate Change, Nuclear Power and Nuclear Proliferation: Magnitude Matters  

SciTech Connect

Integrated energy, environment and economics modeling suggests that worldwide electrical energy use will increase from 2.4 TWe today to ~12 TWe in 2100. It will be challenging to provide 40% of this electrical power from combustion with carbon sequestration, as it will be challenging to provide 30% from renewable energy sources derived from natural energy flows. Thus nuclear power may be needed to provide ~30%, 3600 GWe, by 2100. Calculations of the associated stocks and flows of uranium, plutonium and minor actinides indicate that the proliferation risks at mid-century, using current light-water reactor technology, are daunting. There are institutional arrangements that may be able to provide an acceptable level of risk mitigation, but they will be difficult to implement. If a transition is begun to fast-spectrum reactors at mid-century, without a dramatic change in the proliferation risks of such systems, at the end of the century global nuclear proliferation risks are much greater, and more resistant to mitigation. Fusion energy, if successfully demonstrated to be economically competitive, would provide a source of nuclear power with much lower proliferation risks than fission.

Robert J. Goldston

2011-04-28T23:59:59.000Z

49

The 2D Power Spectrum of the Las Campanas Redshift Survey: Detection of Excess Power on 100 h^{-1} Mpc Scales  

E-Print Network (OSTI)

We have measured the 2 dimensional (2D) power spectrum of the Las Campanas Redshift Survey on scales between 30 and 200 Mpc (q_0=0.5, H_o=100h km sec^{-1} Mpc^{-1}). Such an analysis is more sensitive to structure on scales > 50 Mpc than a full 3 dimensional analysis given the geometry of the survey. We find a strong peak in the power spectrum at approximately 100 Mpc relative to the smooth continuum expected from the best fit Cold Dark Matter model (Probability is 2.5x10^{-4} with Omega h = 0.3 assuming a Gaussian random field). This signal is detected in two independent directions on the sky and has been identified with numerous structures visible in the survey which appear as walls and voids. Therefore, we conclude that there exists a significant increase in power on this scale and that such structures are common features in the local universe, z <= 0.2.

S. D. Landy; S. A. Shectman; H. Lin; R. P. Kirshner; A. A. Oemler; D. Tucker

1995-10-27T23:59:59.000Z

50

Mass Power Spectrum in a Universe Dominated by the Chaplygin Gas  

E-Print Network (OSTI)

The mass power spectrum for a Universe dominated by the Chaplygin gas is evaluated numerically from scales of the order of the Hubble horizon to 100 Mpc. The results are compared with a pure baryonic Universe and a cosmological constant model. In all three cases, the spectrum increases with k, the wavenumber of the perturbations. The slope of the spectrum is higher for the baryonic model and smaller for the cosmological constant model, the Chaplygin gas interpolating these two models. The results are analyzed in terms of the sound velocity of the Chaplygin gas and the moment the Universe begins to accelerate.

J. C. Fabris; S. V. B. Gonçalves; P. E. de Souza

2002-03-25T23:59:59.000Z

51

Dark Stars: the First Stars in the Universe may be powered by Dark Matter Heating  

E-Print Network (OSTI)

A new line of research on Dark Stars is reviewed, which suggests that the first stars to exist in the universe were powered by dark matter heating rather than by fusion. Weakly Interacting Massive Particles, which may be there own antipartmers, collect inside the first stars and annihilate to produce a heat source that can power the stars. A new stellar phase results, a Dark Star, powered by dark matter annihilation as long as there is dark matter fuel.

Katherine Freese; Peter Bodenheimer; Paolo Gondolo; Douglas Spolyar

2008-12-28T23:59:59.000Z

52

Power spectrum and anisotropy of super inflation in loop quantum cosmology  

E-Print Network (OSTI)

We investigate the scalar mode of perturbation of super inflation in the version of loop quantum cosmology in which the gauge invariant holonomy corrections are considered. Given a background solution, we calculate the power spectrum of the perturbation in the classical and LQC conditions. Then we compute the anisotropy originated from the perturbation. It is found that in the presence of the gauge invariant holonomy corrections the power spectrum is exponentially blue and the anisotropy also grows exponentially in the epoch of super inflation.

Xiao-Jun Yue; Jian-Yang Zhu

2012-11-22T23:59:59.000Z

53

The Effect of Radiative Cooling on the Sunyaev-Zel'dovich Cluster Counts and Angular Power Spectrum: Analytic Treatment  

E-Print Network (OSTI)

Recently, the entropy excess detected in the central cores of groups and clusters has been successfully interpreted as being due to radiative cooling of the hot intragroup/intracluster gas. In such a scenario, the entropy floors $S_{\\rm floor}$ in groups/clusters at any given redshift are completely determined by the conservation of energy. In combination with the equation of hydrostatic equilibrium and the universal density profile for dark matter, this allows us to derive the remaining gas distribution of groups and clusters after the cooled material is removed. Together with the Press-Schechter mass function we are able to evaluate effectively how radiative cooling can modify the predictions of SZ cluster counts and power spectrum. It appears that our analytic results are in good agreement with those found by hydrodynamical simulations. Namely, cooling leads to a moderate decrease of the predicted SZ cluster counts and power spectrum as compared with standard scenario. However, without taking into account energy feedback from star formation which may greatly suppress cooling efficiency, it is still premature to claim that this modification is significant for the cosmological applications of cluster SZ effect.

Yu-Ying Zhang; Xiang-Ping Wu

2002-10-01T23:59:59.000Z

54

The Galaxy Angular Correlation Functions and Power Spectrum from the Two Micron All Sky Survey  

E-Print Network (OSTI)

We calculate the angular correlation function of galaxies in the Two Micron All Sky Survey. We minimize the possible contamination by stars, dust, seeing and sky brightness by studying their cross correlation with galaxy density, and limiting the galaxy sample accordingly. We measure the correlation function at scales between 1-18 arcdegs using a half million galaxies. We find a best fit power law to the correlation function has a slope of 0.76 and an amplitude of 0.11. However, there are statistically significant oscillations around this power law. The largest oscillation occurs at about 0.8 degrees, corresponding to 2.8 h^{-1} Mpc at the median redshift of our survey, as expected in halo occupation distribution descriptions of galaxy clustering. We invert the angular correlation function using Singular Value Decomposition to measure the three-dimensional power spectrum and find that it too is in good agreement with previous measurements. A dip seen in the power spectrum at small wavenumber k is statistically consistent with CDM-type power spectra. A fit of CDM-type power spectra to k < 0.2 h Mpc^{-1} give constraints of \\Gamma_{eff}=0.116 and \\sigma_8=0.96. This suggest a K_s-band linear bias of 1.1+/-0.2. This \\Gamma_{eff} is different from the WMAP CMB derived value. On small scales the power-law shape of our power spectrum is shallower than that derived for the SDSS. These facts together imply a biasing of these different galaxies that might be nonlinear, that might be either waveband or luminosity dependent, and that might have a nonlocal origin.

Ariyeh H. Maller; Daniel H. McIntosh; Neal Katz; Martin D. Weinberg

2003-04-01T23:59:59.000Z

55

DASI First Results: A Measurement of the Cosmic Microwave Background Angular Power Spectrum  

E-Print Network (OSTI)

We present measurements of anisotropy in the Cosmic Microwave Background (CMB) from the first season of observations with the Degree Angular Scale Interferometer (DASI). The instrument was deployed at the South Pole in the austral summer 1999--2000, and made observations throughout the following austral winter. We have measured the angular power spectrum of the CMB in the range 100power spectrum at l approx 200, in agreement with previous experiments. In addition, we detect a peak in the power spectrum at l approx 550 and power of similar magnitude at l approx 800 which are consistent with the second and third harmonic peaks predicted by adiabatic inflationary cosmological models.

N. W. Halverson; E. M. Leitch; C. Pryke; J. Kovac; J. E. Carlstrom; W. L. Holzapfel; M. Dragovan; J. K. Cartwright; B. S. Mason; S. Padin; T. J. Pearson; M. C. Shepherd; A. C. S. Readhead

2001-04-30T23:59:59.000Z

56

Reconstruction of a nonminimal coupling theory with scale-invariant power spectrum  

SciTech Connect

A nonminimal coupling single scalar field theory, when transformed from Jordan frame to Einstein frame, can act like a minimal coupling one. Making use of this property, we investigate how a nonminimal coupling theory with scale-invariant power spectrum could be reconstructed from its minimal coupling counterpart, which can be applied in the early universe. Thanks to the coupling to gravity, the equation of state of our universe for a scale-invariant power spectrum can be relaxed, and the relation between the parameters in the action can be obtained. This approach also provides a means to address the Big-Bang puzzles and anisotropy problem in the nonminimal coupling model within Jordan frame. Due to the equivalence between the two frames, one may be able to find models that are free of the horizon, flatness, singularity as well as anisotropy problems.

Qiu, Taotao, E-mail: qiutt@ntu.edu.tw [Leung Center for Cosmology and Particle Astrophysics National Taiwan University, Taipei 106, Taiwan (China)

2012-06-01T23:59:59.000Z

57

Revisiting a pre-inflationary radiation era and its effect on the CMB power spectrum  

E-Print Network (OSTI)

We revisit the scenario where inflation is preceded by a radiation era by considering that the inflaton too could have been in thermal equilibrium early in the radiation era. Hence we take into account not only the effect of a pre-inflationary era on the inflaton mode functions but also that of a frozen thermal distribution of inflaton quanta. We initially discuss in detail the issues relevant to our scenario of a pre-inflationary radiation dominated era and then obtain the scalar power spectrum for this scenario. We find that the power spectrum is free from infrared divergences. We then use the WMAP and Planck data to determine the constraints on the inflaton comoving `temperature' and on the duration of inflation. We find that the best fit value of the duration of inflation is less than 1 e-folding more than what is required to solve cosmological problems, while only an upper bound on the inflaton temperature can be obtained.

Das, Suratna; Prasad, Jayanti; Rangarajan, Raghavan

2014-01-01T23:59:59.000Z

58

Secondary infall model of galactic halo formation and the spectrum of cold dark matter particles on Earth  

Science Journals Connector (OSTI)

The spectrum of cold dark matter particles on Earth is expected to have peaks in velocity space associated with particles which are falling onto the Galaxy for the first time and with particles which have fallen in and out of the Galaxy only a small number of times in the past. We obtain estimates for the velocity magnitudes and the local densities of the particles in these peaks. To this end we use the secondary infall model of galactic halo formation which we have generalized to take account of the angular momentum of the dark matter particles. The new model is still spherically symmetric and it admits self-similar solutions. In the absence of angular momentum, the model produces flat rotation curves for a large range of values of a parameter ? which is related to the spectrum of primordial density perturbations. We find that the presence of angular momentum produces an effective core radius; i.e., it makes the contribution of the halo to the rotation curve go to zero at zero radius. The model provides a detailed description of the large scale properties of galactic halos including their density profiles, their extent, and total mass. We obtain predictions for the kinetic energies of the particles in the velocity peaks and estimates for their local densities as functions of the amount of angular momentum, the age of the Universe, and ?.

P. Sikivie; I. I. Tkachev; Yun Wang

1997-08-15T23:59:59.000Z

59

DARK MATTER Tracing the "Cosmic Web" with Diffuse Gas  

E-Print Network (OSTI)

1 DARK MATTER STARS GAS NEUTRAL HYDROGEN Tracing the "Cosmic Web" with Diffuse Gas Quasar Quasar Absorption Lines Keck/HIRES Quasar Spectrum Observer baryons dark matter potential isotropic UV only on and the radiation field intensity... H I #12;5 GOAL: the primordial dark matter power spectrum

Steidel, Chuck

60

VES-0071- In the Matter of Mississippi Power Company  

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

On May 1, 2000, the Mississippi Power Company, of Gulfport, Mississippi (Mississippi Power), filed with the Office of Hearings and Appeals (OHA) of the Department of Energy an Application for...

Note: This page contains sample records for the topic "matter power spectrum" 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

Angular Signatures of Dark Matter in the Diffuse Gamma Ray Spectrum  

SciTech Connect

Dark matter annihilating in our Galaxy's halo and elsewhere in the universe is expected to generate a diffuse flux of gamma rays, potentially observable with next generation satellite-based experiments, such as GLAST. In this article, we study the signatures of dark matter in the angular distribution of this radiation. Pertaining to the extragalactic contribution, we discuss the effect of the motion of the solar system with respect to the cosmological rest frame, and anisotropies due to the structure of our local universe. For the gamma ray flux from dark matter in our own Galactic halo, we discuss the effects of the offset position of the solar system, the Compton-Getting effect, the asphericity of the Milky Way halo, and the signatures of nearby substructure. We explore the prospects for the detection of these features by the GLAST satellite and find that, if {approx} 10% or more of the diffuse gamma ray background observed by EGRET is the result of dark matter annihilations, then GLAST should be sensitive to anisotropies down to the 0.1% level. Such precision would be sufficient to detect many, if not all, of the signatures discussed in this paper.

Hooper, Dan; Serpico, Pasquale D.; /Fermilab

2007-02-01T23:59:59.000Z

62

Tore Supra LH transmitter upgrade, a new RF driver for the power spectrum  

SciTech Connect

New real time tools have been developed for testing new 700kW/3.7GHz/CW klystrons and for the operations on very long plasma shots. After the commissioning of the 18 series tubes on the high power test bed facility, the installation of the first 8 klystrons in the Tore Supra transmitter and the adjustment tests on load, this upgrade work has been materialized during the last 2010 campaign by a successful operation on the Full Active Multijunction (FAM) C3 antenna, with new performances: 3.5MW/40s on plasma. The RF output power control in amplitude and phase has been improved for a better control of the wave spectrum launched into the plasma. The new klystrons have no modulating anode and the high cathode voltage must be adjusted with the RF input power in order to optimize the RF output power with a minimization of the thermal power losses in the collector. A new phase correction, depending on the 3 RF output power ranges used, has been introduced. The improvements made in 2009 and 2010 on the generic phase loop and the procedures used during the real time tests of the RF transfer functions in amplitude and phase are detailed below. All RF measurements systems, RF safety systems and the RF calibration procedures have been revised in order to have the best consistency, reproducibility and with a measurement error against the calorimetry measurement lower than 10%.

Berger-By, G.; Achard, J.; Armitano, A.; Bouquey, F.; Corbel, E.; Delpech, L.; Ekedahl, A.; Lombard, G.; Magne, R.; Mollard, P.; Pagano, M.; Prou, M.; Samaille, F.; Volpe, D.; Volpe, R. [CEA IRFM, F-13108 Saint-Paul-Lez-Durance (France)

2011-12-23T23:59:59.000Z

63

Energy Spectrum of the Electrons Accelerated by a Reconnection Electric Field: Exponential or Power Law?  

E-Print Network (OSTI)

The direct current (DC) electric field near the reconnection region has been proposed as an effective mechanism to accelerate protons and electrons in solar flares. A power-law energy spectrum was generally claimed in the simulations of electron acceleration by the reconnection electric field. However in most of the literature, the electric and magnetic fields were chosen independently. In this paper, we perform test-particle simulations of electron acceleration in a reconnecting magnetic field, where both the electric and magnetic fields are adopted from numerical simulations of the MHD equations. It is found that the accelerated electrons present a truncated power-law energy spectrum with an exponential tail at high energies, which is analogous to the case of diffusive shock acceleration. The influences of reconnection parameters on the spectral feature are also investigated, such as the longitudinal and transverse components of the magnetic field and the size of the current sheet. It is suggested that the DC electric field alone might not be able to reproduce the observed single or double power-law distributions.

W. J. Liu; P. F. Chen; M. D. Ding; C. Fang

2008-09-07T23:59:59.000Z

64

Constraining the intra-cluster pressure profile from the thermal SZ power spectrum  

E-Print Network (OSTI)

The angular power spectrum of the thermal Sunyaev-Zel'dovich (tSZ) effect is highly sensitive to cosmological parameters such as sigma8 and OmegaM, but its use as a precision cosmological probe is hindered by the astrophysical uncertainties in modeling the gas pressure profile in galaxy groups and clusters. In this paper we assume that the relevant cosmological parameters are accurately known, and explore the ability of current and future tSZ power spectrum measurements to constrain the intra-cluster gas pressure or the evolution of the gas mass fraction, f_gas. We use the CMB bandpower measurements from the South Pole Telescope and a Bayesian MCMC method to quantify deviations from the standard, universal gas pressure model. We explore analytical model extensions that bring the predictions for the tSZ power in agreement with experimental data. We find that a steeper pressure profile in the cluster outskirts or an evolving f_gas have mild to severe conflicts with experimental data or simulations. Varying more...

Ramos-Ceja, M E; Pacaud, F; Bertoldi, F

2014-01-01T23:59:59.000Z

65

A power line impedance spectrum analyzer using real-time digital signal processing  

E-Print Network (OSTI)

. The subscript on each source corresponds to the harmonic generated by that source and all sources were set to an amplitude of O. lmA. The output files obtained from a transient analysis were then transferred to Matlab, and impedance spectrums were generated... Harmonic Number Figure 12 Simulated lmH Load Next the power network was simulated both with and without the attachment of the non-linear load. The voltage across the linear load was measured and plotted in the frequency domain using Matlab. Figure 13...

Margolis, Michael G

2012-06-07T23:59:59.000Z

66

Power spectrum of large-scale magnetic fields from Gravitoelectromagnetic inflation with a decaying cosmological parameter  

E-Print Network (OSTI)

Introducing a variable cosmological parameter $\\Lambda (t)$ in a geometrical manner from a 5D Riemann-flat metric, we investigate the origin and evolution of primordial magnetic fields in the early universe, when the expansion is governed by a cosmological parameter $\\Lambda (t)$ that decreases with time. Using the gravitoelectromagnetic inflationary formalism, but without the Feynman gauge, we obtain the power of spectrums for large-scale magnetic fields and the inflaton field fluctuations during inflation. A very important fact is that our formalism is {\\em naturally non-conformally invariant}.

Federico Agustin Membiela; Mauricio Bellini

2007-12-18T23:59:59.000Z

67

VEA-0009 - In the Matter of American Electric Power Company, Inc. |  

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

09 - In the Matter of American Electric Power Company, Inc. 09 - In the Matter of American Electric Power Company, Inc. VEA-0009 - In the Matter of American Electric Power Company, Inc. This Decision and Order considers an Appeal filed by American Electric Power Company, Inc. (AEP) from a determination issued on July 7, 1998, by the Office of Energy Efficiency and Renewable Energy (EE) of the Department of Energy (DOE), under provisions of 10 C.F.R. Part 490 (Alternative Fuel Transportation Program). In its determination, EE substantially denied a request filed by AEP for an exemption from the firm's 1998 Model Year (MY) alternative fuel vehicle (AFV) purchase requirements under the Part 490 program. If the present Appeal were granted, AEP would be exempted from its 1998 MY purchase requirements, as initially requested by the firm. As

68

VEA-0012 - In the Matter of American Electric Power Company, Inc. |  

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

12 - In the Matter of American Electric Power Company, Inc. 12 - In the Matter of American Electric Power Company, Inc. VEA-0012 - In the Matter of American Electric Power Company, Inc. This Decision and Order considers an Appeal filed by American Electric Power Company, Inc. (AEP) from a determination issued on October 15, 1999, by the Office of Energy Efficiency and Renewable Energy (EE) of the Department of Energy (DOE), under provisions of 10 C.F.R. Part 490 (Alternative Fuel Transportation Program). In its determination, EE granted in part a request filed by AEP for an exemption from the firm's 1998 and 1999 Model Year (MY) alternative fuel vehicle (AFV) purchase requirements under the Part 490 program. If the present Appeal were granted, AEP would be granted exemptions from its 1998 MY purchase requirements, in addition

69

Low power implementation of audio watermarking using chirp spread spectrum technique  

Science Journals Connector (OSTI)

There are numerous implementations of software-based audio watermarking available, but the implementation of hardware-based audio watermarking helps to achieve real time performance by integrating an audio watermarking chip with an existing audio electronic device. For the secure communication of the secret messages and for the data protection, the watermarking should provide good imperceptibility, good robustness, high capacity (pay load) and high speed. Thus, this paper presents a new VLSI architecture to implement an audio watermarking using chirp spread spectrum technique. It uses a chirp signal as a secret key; the watermark message can be transmitted as a noise signal such that an intruder cannot retrieve the message which is transmitted, and the message can be retrieved at the receiver side only with the help of the secret key. This technique provides high security with a low power and less complexity and it is very difficult to detect and intercept, hence it is used for the application of military and wireless communication to provide a covert communication. To our knowledge, we are the first authors to propose the low power implementation of audio watermarking using spread spectrum technique.

P. Karthigaikumar; K. Baskaran; K. Jaraline Kirubavathy

2011-01-01T23:59:59.000Z

70

Power Spectrum of Out-of-equilibrium Forces in Living Cells : Amplitude and Frequency Dependence  

E-Print Network (OSTI)

Living cells exhibit an important out-of-equilibrium mechanical activity, mainly due to the forces generated by molecular motors. These motor proteins, acting individually or collectively on the cytoskeleton, contribute to the violation of the fluctuation-dissipation theorem in living systems. In this work we probe the cytoskeletal out-of-equilibrium dynamics by performing simultaneous active and passive microrheology experiments, using the same micron-sized probe specifically bound to the actin cortex. The free motion of the probe exhibits a constrained, subdiffusive behavior at short time scales (t power law dependence with time. Combining the results of both experiments, we precisely measure for the first time the power spectrum of the force fluctuations exerted on this probe, which lies more than one order of magnitude above the spectrum expected at equilibrium, and greatly depends on frequency. We retrieve an effective temperature Teff of the system, as an estimate of the departure from thermal equilibrium. This departure is especially pronounced on long time scales, where Teff bears the footprint of the cooperative activity of motors pulling on the actin network. ATP depletion reduces the fluctuating force amplitude and results in a sharp decrease of Teff towards equilibrium.

Francois Gallet; Delphine Arcizet; Pierre Bohec; Alain Richert

2009-01-20T23:59:59.000Z

71

Gas Density Fluctuations in the Perseus Cluster: Clumping Factor and Velocity Power Spectrum  

E-Print Network (OSTI)

X-ray surface brightness fluctuations in the core of the Perseus Cluster are analyzed, using deep observations with the Chandra observatory. The amplitude of gas density fluctuations on different scales is measured in a set of radial annuli. It varies from 8 to 12 per cent on scales of ~10-30 kpc within radii of 30-160 kpc from the cluster center and from 9 to 7 per cent on scales of ~20-30 kpc in an outer, 60-220 kpc annulus. Using a statistical linear relation between the observed amplitude of density fluctuations and predicted velocity, the characteristic velocity of gas motions on each scale is calculated. The typical amplitudes of the velocity outside the central 30 kpc region are 90-140 km/s on ~20-30 kpc scales and 70-100 km/s on smaller scales ~7-10 kpc. The velocity power spectrum is consistent with cascade of turbulence and its slope is in a broad agreement with the slope for canonical Kolmogorov turbulence. The gas clumping factor estimated from the power spectrum of the density fluctuations is low...

Zhuravleva, I; Arevalo, P; Schekochihin, A A; Allen, S W; Fabian, A C; Forman, W R; Sanders, J S; Simionescu, A; Sunyaev, R; Vikhlinin, A; Werner, N

2015-01-01T23:59:59.000Z

72

Power spectrum in the Chaplygin gas model: tachyonic, fluid and scalar field representations  

E-Print Network (OSTI)

The Chaplygin gas model, characterized by an equation of state of the type $p = - \\frac{A}{\\rho}$ emerges naturally from the Nambu-Goto action of string theory. This fluid representation can be recast under the form of a tachyonic field given by a Born-Infeld type Lagrangian. At the same time, the Chaplygin gas equation of state can be obtained from a self-interacting scalar field. We show that, from the point of view of the supernova type Ia data, the three representations (fluid, tachyonic, scalar field) lead to the same results. However, concerning the matter power spectra, while the fluid and tachyonic descriptions lead to exactly the same results, the self-interacting scalar field representation implies different statistical estimations for the parameters. In particular, the estimation for the dark matter density parameter in the fluid representation favors a universe dominated almost completely by dark matter, while in the self-interacting scalar field representation the prediction is very closed to that obtained in the $\\Lambda$CDM model.

C. E. M. Batista; J. C. Fabris; M. Morita

2009-04-24T23:59:59.000Z

73

The power spectrum of the Milky Way: Velocity fluctuations in the Galactic disk  

E-Print Network (OSTI)

We investigate the kinematics of stars in the mid-plane of the Milky Way on scales between 25 pc and 10 kpc with data from the Apache Point Observatory Galactic Evolution Experiment (APOGEE), the Radial Velocity Experiment (RAVE), and the Geneva-Copenhagen Survey (GCS). Using red-clump stars in APOGEE, we determine the large-scale line-of-sight velocity field out to 5 kpc from the Sun in (0.75 kpc)^2 bins. The solar motion is the largest contribution to the power on large scales after subtracting an axisymmetric rotation field; we determine the solar motion by minimizing the large-scale power to be V_sun = 24+/-1 (ran.)+/-2 (syst [V_c])+/-5 (syst. [large-scale]) km/s, where the systematic uncertainty is due to (a) a conservative 20 km/s uncertainty in V_c and (b) the estimated power on unobserved larger scales. Combining the APOGEE peculiar-velocity field with red-clump stars in RAVE out to 2 kpc from the Sun and with local GCS stars, we determine the power spectrum of residual velocity fluctuations in the Mi...

Bovy, Jo; Pérez, Ana E García; Zasowski, Gail

2014-01-01T23:59:59.000Z

74

A pulsed power hydrodynamics approach to exploring properties of warm dense matter  

SciTech Connect

Pulsed Power Hydrodynamics, as an application of low-impedance, pulsed power, and high magnetic field technology developed over the last decade to study advanced hydrodynamic problems, instabilities, turbulence, and material properties, can potentially be applied to the study of the behavior and properties of warm dense matter (WDM) as well. Exploration of the properties, such as equation of state and conductivity, of warm dense matter is an emerging area of study focused on the behavior of matter at density near solid density (from 10% of solid density to a few times solid density) and modest temperatures ({approx}1-10 eV). Warm dense matter conditions can be achieved by laser or particle beam heating of very small quantities of matter on timescales short compared to the subsequent hydrodynamic expansion timescales (isochoric heating) and a vigorous community of researchers is applying these techniques using petawatt scale laser systems, but the microscopic size scale of the WDM produced in this way limits access to some physics phenomena. Pulsed power hydrodynamics techniques, either through high convergence liner compression of a large volume, modest density, low temperature plasma to densities approaching solid density or through the explosion and subsequent expansion of a conductor (wire) against a high pressure (density) gas background (isobaric expansion) techniques both offer the prospect for producing warm dense matter in macroscopic quantities. However, both techniques demand substantial energy, proper power conditioning and delivery, and an understanding of the hydrodynamic and instability processes that limit each technique. Similarly, liner compression of normal density material, perhaps using multiple reflected shocks can provide access to the challenging region above normal density -- again with the requirement of very large amounts of driving energy. In this paper we will provide an introduction to techniques that might be applied to explore this interesting new application of the energy-rich technology of pulse power and high magnetic fields.

Reinovsky, Robert Emil [Los Alamos National Laboratory

2008-01-01T23:59:59.000Z

75

PkANN: Non-Linear Matter Power Spectrum Interpolation through Artificial Neural Networks  

E-Print Network (OSTI)

, for which one can solve analytically, to non-linear, for which one cannot. Using N-body simulations [Heit- mann et al., 2010, Agarwal and Feldman, 2011] and analytical studies inspired from perturbation theory (PT) [Scoccimarro et al., 1999, Saito et al...

Agarwal, Shankar

2012-12-31T23:59:59.000Z

76

The 21cm power spectrum and the shapes of non-Gaussianity  

SciTech Connect

We consider how measurements of the 21cm radiation from the epoch of reionization (z = 8?12) can constrain the amplitudes of various 'shapes' of primordial non-Gaussianity. The limits on these shapes, each parametrized by the non-linear parameter f{sub NL}, can reveal whether the physics of inflation is more complex than the standard single-field, slow-roll scenario. In this work, we quantify the effects of the well-known local, equilateral, orthogonal and folded types of non-Gaussianities on the 21cm power spectrum, which is expected to be measured by upcoming radio arrays such as the Square-Kilometre Array (SKA). We also assess the prospects of the SKA in constraining these non-Gaussianities, and found constraints that are comparable with those from cosmic-microwave-background experiments such as Planck. We show that the limits on various f{sub NL} can be tightened to O(1) using a radio array with a futuristic but realistic set of specifications.

Chongchitnan, Sirichai, E-mail: s.chongchitnan@abertay.ac.uk [School of Engineering, Computing and Applied Mathematics, University of Abertay Dundee, Bell St., Dundee, DD1 1HG, Scotland (United Kingdom)

2013-03-01T23:59:59.000Z

77

Constraining models of $f(R)$ gravity with Planck and WiggleZ power spectrum data  

E-Print Network (OSTI)

In order to explain cosmic acceleration without invoking "dark" physics, we consider $f(R)$ modified gravity models, which replace the standard Einstein-Hilbert action in General Relativity with a higher derivative theory. We use data from the WiggleZ Dark Energy survey to probe the formation of structure on large scales which can place tight constraints on these models. We combine the large-scale structure data with measurements of the cosmic microwave background from the Planck surveyor. After parameterising the modification of the action using the Compton wavelength parameter $B_0$, we constrain this parameter using ISiTGR, assuming an initial non-informative log prior probability distribution of this cross-over scale. We find that the addition of the WiggleZ power spectrum provides the tightest constraints to date on $B_0$ by an order of magnitude, giving ${\\rm log}_{10}(B_0) < -4.07$ at 95% confidence limit. Finally, we test whether the effect of adding the lensing amplitude $A_{\\rm Lens}$ and the sum...

Dossett, Jason; Parkinson, David

2014-01-01T23:59:59.000Z

78

Constraining models of $f(R)$ gravity with Planck and WiggleZ power spectrum data  

E-Print Network (OSTI)

In order to explain cosmic acceleration without invoking "dark" physics, we consider $f(R)$ modified gravity models, which replace the standard Einstein-Hilbert action in General Relativity with a higher derivative theory. We use data from the WiggleZ Dark Energy survey to probe the formation of structure on large scales which can place tight constraints on these models. We combine the large-scale structure data with measurements of the cosmic microwave background from the Planck surveyor. After parameterising the modification of the action using the Compton wavelength parameter $B_0$, we constrain this parameter using ISiTGR, assuming an initial non-informative log prior probability distribution of this cross-over scale. We find that the addition of the WiggleZ power spectrum provides the tightest constraints to date on $B_0$ by an order of magnitude, giving ${\\rm log}_{10}(B_0) < -4.07$ at 95% confidence limit. Finally, we test whether the effect of adding the lensing amplitude $A_{\\rm Lens}$ and the sum of the neutrino mass $\\sum m_\

Jason Dossett; Bin Hu; David Parkinson

2014-01-16T23:59:59.000Z

79

Power Spectrum of the density of cold atomic gas in the Galaxy towards Cas A and Cygnus A  

E-Print Network (OSTI)

We have obtained the power spectral description of the density and opacity fluctuations of the cold HI gas in the Galaxy towards Cas A, and Cygnus A. We have employed a method of deconvolution, based on CLEAN, to estimate the true power spectrum of optical depth of cold HI gas from the observed distribution, taking into account the finite extent of the background source and the incomplete sampling of optical depth over the extent of the source. We investigate the nature of the underlying spectrum of density fluctuations in the cold HI gas which would be consistent with that of the observed HI optical depth fluctuations. These power spectra for the Perseus arm towards Cas A, and for the Outer arm towards Cygnus A have a slope of 2.75 +/- 0.25 (3sigma error). The slope in the case of the Local arm towards Cygnus A is 2.5, and is significantly shallower in comparison. The linear scales probed here range from 0.01 to 3 pc. We discuss the implications of our results, the non-Kolmogorov nature of the spectrum, and the observed HI opacity variations on small transverse scales.

A. A. Deshpande; K. S. Dwarakanath; W. M. Goss

2000-07-25T23:59:59.000Z

80

The effect of aberration on partial-sky measurements of the cosmic microwave background temperature power spectrum  

E-Print Network (OSTI)

Our motion relative to the cosmic-microwave-background (CMB) rest frame deflects light rays giving rise to shifts as large as L -> L(1+-beta), where beta=0.00123 is our velocity (in units of the speed of light) on measurements of small-scale (large multipole moment L) CMB fluctuations. For measurements at L>1000, where the CMB power spectrum varies roughly as C(L) ~ L^-7, the fractional change to the power spectrum measured on a small sky patch can be as large as Delta C(L)/C(L)~7*beta~1%, larger than the measurement uncertainties in several current experiments. Here we present a novel harmonic-space approach to this CMB aberration that improves upon prior work by allowing us to (i) go to higher orders in beta, thus extending the validity of the analysis to measurements at L>1/beta~800; and (ii) treat the effects of window functions and pixelization in a more accurate and computationally efficient manner. We calculate precisely the magnitude of the systematic bias in the power spectrum inferred from current S...

Jeong, Donghui; Dai, Liang; Kamionkowski, Marc; Wang, Xin

2014-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "matter power spectrum" 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

E-Print Network 3.0 - angular power spectrum Sample Search Results  

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

energy E so fast-wave heating power P * interpretation being angular... minority ion-cyclotron heating, even though process introduces negligible ... Source: Princeton Plasma...

82

Detection of periodic signatures in the solar power spectrum. On the track of l=1 gravity modes  

E-Print Network (OSTI)

In the present work we show robust indications of the existence of g modes in the Sun using 10 years of GOLF data. The present analysis is based on the exploitation of the collective properties of the predicted low-frequency (25 to 140 microHz) g modes: their asymptotic nature, which implies a quasi equidistant separation of their periods for a given angular degree (l). The Power Spectrum (PS) of the Power Spectrum Density (PSD), reveals a significant structure indicating the presence of features (peaks) in the PSD with near equidistant periods corresponding to l=1 modes in the range n=-4 to n=-26. The study of its statistical significance of this feature was fully undertaken and complemented with Monte Carlo simulations. This structure has a confidence level better than 99.86% not to be due to pure noise. Furthermore, a detailed study of this structure suggests that the gravity modes have a much more complex structure than the one initially expected (line-widths, magnetic splittings...). Compared to the late...

García, R A; Jiménez-Reyes, S J; Ballot, J; Pallé, P L; Eff-Darwich, A; Mathur, S; Provost, J

2006-01-01T23:59:59.000Z

83

A Gamma-Ray Burst/Pulsar for Cosmic-Ray Positrons with a Dark Matter-like Spectrum  

E-Print Network (OSTI)

We propose that a nearby gamma-ray burst (GRB) or GRB-like (old, single and short-lived) pulsar/supernova remnant/microquasar about 10^{5-6} years ago may be responsible for the excesses of cosmic-ray positrons and electrons recently observed by the PAMELA, ATIC/PPB-BETS, Fermi and HESS experiments. We can reproduce the smooth Fermi/HESS spectra as well as the spiky ATIC/PPB-BETS spectra. The spectra have a sharp cutoff that is similar to the dark matter predictions, sometimes together with a line (not similar), since higher energy cosmic-rays cool faster where the cutoff/line energy marks the source age. A GRB-like astrophysical source is expected to have a small but finite spread in the cutoff/line as well as anisotropy in the cosmic-ray and diffuse gamma-ray flux, providing a method for the Fermi and future CALET experiments to discriminate between dark matter and astrophysical origins.

Kunihito Ioka

2010-06-15T23:59:59.000Z

84

A study of wind variability in the lower troposphere through power spectrum analysis at mesoscale frequencies  

E-Print Network (OSTI)

on the theoretical and practical application of the analysis method comes directly from this reference. B. Fundamental Assum tions of Power S ectrum Theor Consider a function of time X(t), such as wind speed, which is generated by a random process. Then the value... of the function X(t) at any particular point in time is a random variable. This random process may or may not have a Gaussian or normal distribution but it is a fundamental assumption (at least in the development of the theory) that the random process...

Cornett, John Sheldon

1966-01-01T23:59:59.000Z

85

A METHOD TO EXTRACT THE ANGULAR POWER SPECTRUM OF THE EPOCH OF REIONIZATION FROM LOW-FREQUENCY RADIO INTERFEROMETERS  

SciTech Connect

The redshifted 21 cm signal of neutral hydrogen from the epoch of reionization (EoR) is extremely weak and its first detection is therefore expected to be statistical with first-generation low-frequency radio interferometers. In this Letter, we propose a method to extract the angular power spectrum of the EoR from the visibility correlation coefficients p{sub ij} (u, v), instead of the visibilities V{sub ij} (u, v) measured directly by radio interferometers in conventional algorithm. The visibility correlation coefficients are defined as p{sub ij}(u,v)=V{sub ij}(u,v)/{radical}(|V{sub ii}||V{sub jj}|) by introducing the autocorrelation terms V{sub ii} and V{sub jj} such that the angular power spectrum C{sub l} can be obtained through C{sub l} = T {sup 2}{sub 0}(|p{sub ij} (u, v)|{sup 2}), independently of the primary beams of antennas. This also partially removes the influence of receiver gains in the measurement of C{sub l} because the amplitudes of the gains cancel each other out in the statistical average operation of (|p{sub ij} (u, v)|{sup 2}). We use the average system temperature T{sub 0} as a calibrator of C{sub l}, which is dominated by the Milky Way and extragalactic sources in the frequency range that we are interested in, below 200 MHz. Finally, we demonstrate the feasibility of this novel method using the simulated sky maps as targets and the 21 CentiMeter Array (21CMA) as interferometer.

Zheng Qian; Wu Xiangping; Gu Junhua [National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China); Wang Jingying; Xu Haiguang [Department of Physics, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240 (China)

2012-10-10T23:59:59.000Z

86

SLIM at LHC: LHC search power for a model linking dark matter and neutrino mass  

Science Journals Connector (OSTI)

Recently a model has been proposed that links dark matter and neutrino masses. The dark matter candidate which is dubbed as SLIM has a mass of MeV scale and can show up at low energy experiments. The model als...

Y. Farzan; M. Hashemi

2010-11-01T23:59:59.000Z

87

FOREGROUND PREDICTIONS FOR THE COSMIC MICROWAVE BACKGROUND POWER SPECTRUM FROM MEASUREMENTS OF FAINT INVERTED RADIO SOURCES AT 5 GHz  

SciTech Connect

We present measurements of a population of matched radio sources at 1.4 and 5 GHz down to a flux limit of 1.5 mJy in 7 deg{sup 2} of the NOAO Deep Field South. We find a significant fraction of sources with inverted spectral indices that all have 1.4 GHz fluxes less than 10 mJy and are therefore too faint to have been detected and included in previous radio source count models that are matched at multiple frequencies. Combined with the matched source population at 1.4 and 5 GHz in 1 deg{sup -2} in the ATESP survey, we update models for the 5 GHz differential number counts and distributions of spectral indices in 5 GHz flux bins that can be used to estimate the unresolved point source contribution to the cosmic microwave background temperature anisotropies. We find a shallower logarithmic slope in the 5 GHz differential counts than in previously published models for fluxes {approx}< 100 mJy as well as larger fractions of inverted spectral indices at these fluxes. Because the Planck flux limit for resolved sources is larger than 100 mJy in all channels, our modified number counts yield at most a 10% change in the predicted Poisson contribution to the Planck temperature power spectrum. For a flux cut of 5 mJy with the South Pole Telescope and a flux cut of 20 mJy with the Atacama Cosmology Telescope, we predict a {approx}30% and {approx}10% increase, respectively, in the radio source Poisson power in the lowest frequency channels of each experiment relative to that predicted by previous models.

Schneider, Michael D. [Lawrence Livermore National Laboratory, P.O. Box 808 L-210, Livermore, CA 94551 (United States); Becker, Robert H. [Department of Physics, University of California, One Shields Avenue, Davis, CA 08991 (United States); De Vries, Willem [Lawrence Livermore National Laboratory, P.O. Box 808 L-211, Livermore, CA 94551 (United States); White, Richard L., E-mail: schneider42@llnl.gov [Space Telescope Science Institute, Baltimore, MD 21218 (United States)

2012-05-10T23:59:59.000Z

88

Practitioner Perspectives Matter: Public Policy and Private Investment in the U.S. Electric Power Sector  

E-Print Network (OSTI)

a boom-bust cycle in wind power plant investment in the U.S.tax credit for wind turbine power plants is an ineffectivewind power and became comfortable with turbine technology and plant

Barradale, Merrill Jones

2010-01-01T23:59:59.000Z

89

CMB power spectrum contribution from cosmic strings using field-evolution simulations of the Abelian Higgs model  

E-Print Network (OSTI)

We present the first field-theoretic calculations of the contribution made by cosmic strings to the temperature power spectrum of the cosmic microwave background (CMB). Unlike previous work, in which strings were modeled as idealized one-dimensional objects, we evolve the simplest example of an underlying field theory containing local U(1) strings, the Abelian Higgs model. Limitations imposed by finite computational volumes are overcome using the scaling property of string networks and a further extrapolation related to the lessening of the string width in comoving coordinates. The strings and their decay products, which are automatically included in the field theory approach, source metric perturbations via their energy-momentum tensor, the unequal-time correlation functions of which are used as input into the CMB calculation phase. These calculations involve the use of a modified version of CMBEASY, with results provided over the full range of relevant scales. We find that the string tension $\\mu$ required to normalize to the WMAP 3-year data at multipole $\\ell = 10$ is $G\\mu = [2.04\\pm0.06\\textrm{(stat.)}\\pm0.12\\textrm{(sys.)}] \\times 10^{-6}$, where we have quoted statistical and systematic errors separately, and $G$ is Newton's constant. This is a factor 2-3 higher than values in current circulation.

Neil Bevis; Mark Hindmarsh; Martin Kunz; Jon Urrestilla

2006-04-30T23:59:59.000Z

90

Reduced shear power spectrum  

SciTech Connect

Measurements of ellipticities of background galaxies are sensitive to the reduced shear, the cosmic shear divided by (1-{kappa}) where {kappa} is the projected density field. They compute the difference between shear and reduced shear both analytically and with simulations. The difference becomes more important an smaller scales, and will impact cosmological parameter estimation from upcoming experiments. A simple recipe is presented to carry out the required correction.

Dodelson, Scott; /Fermilab /Chicago U., Astron. Astrophys. Ctr. /Northwestern U.; Shapiro, Charles; /Chicago U. /KICP, Chicago; White, Martin J.; /UC, Berkeley, Astron.

2005-08-01T23:59:59.000Z

91

Practitioner Perspectives Matter: Public Policy and Private Investment in the U.S. Electric Power Sector  

E-Print Network (OSTI)

As long as the value of wind power to the utility is 3¢/kWhAs long as the value of wind power to the utility is 5¢/kWh

Barradale, Merrill Jones

2010-01-01T23:59:59.000Z

92

D matter  

Science Journals Connector (OSTI)

We study the properties and phenomenology of particlelike states originating from D branes whose spatial dimensions are all compactified. They are nonperturbative states in string theory and we refer to them as D matter. In contrast to other nonperturbative objects such as ’t Hooft–Polyakov monopoles, D-matter states could have perturbative couplings among themselves and with ordinary matter. The lightest D particle (LDP) could be stable because it is the lightest state carrying certain (integer or discrete) quantum numbers. Depending on the string scale, they could be cold dark matter candidates with properties similar to that of WIMPs or wimpzillas. The spectrum of excited states of D matter exhibits an interesting pattern which could be distinguished from that of Kaluza-Klein modes, winding states, and string resonances. We speculate about possible signatures of D matter from ultrahigh energy cosmic rays and colliders.

Gary Shiu and Lian-Tao Wang

2004-06-29T23:59:59.000Z

93

A Fast Gridded Method for the Estimation of the Power Spectrum of the CMB from Interferometer Data with Application to the Cosmic Background Imager  

E-Print Network (OSTI)

We describe an algorithm for the extraction of the angular power spectrum of an intensity field, such as the cosmic microwave background (CMB), from interferometer data. This new method, based on the gridding of interferometer visibilities in the aperture plane followed by a maximum likelihood solution for bandpowers, is much faster than direct likelihood analysis of the visibilities, and deals with foreground radio sources, multiple pointings, and differencing. The gridded aperture-plane estimators are also used to construct Wiener-filtered images using the signal and noise covariance matrices used in the likelihood analysis. Results are shown for simulated data. The method has been used to determine the power spectrum of the cosmic microwave background from observations with the Cosmic Background Imager, and the results are given in companion papers.

S. T. Myers; C. R. Contaldi; J. R. Bond; U. -L. Pen; D. Pogosyan; S. Prunet; J. L. Sievers; B. S. Mason; T. J. Pearson; A. C. S. Readhead; M. C. Shepherd

2002-05-23T23:59:59.000Z

94

The GMRT-EoR Experiment: A new upper limit on the neutral hydrogen power spectrum at z \\approx 8.6  

E-Print Network (OSTI)

We present a new upper limit to the 21cm power spectrum during the Epoch of Reionization (EoR) which constrains reionization models with an unheated IGM. The GMRT-EoR experiment is an ongoing effort to make a statistical detection of the power spectrum of 21cm neutral hydrogen emission at redshift z~9. Data from this redshift constrain models of the (EoR), the end of the Dark Ages arising from the formation of the first bright UV sources, probably stars or mini-quasars. We present results from approximately 50 hours of observations at the Giant Metrewave Radio Telescope in India from December 2007. We describe radio frequency interference (RFI) localisation schemes which allow bright sources on the ground to be identified and physically removed. Singular-value decomposition is used to remove remaining broadband RFI by identifying ground sources with large eigenvalues. Foregrounds are modelled using a piecewise linear filter and the power spectrum is measured using cross-correlations of foreground subtracted i...

Paciga, Gregory; Gupta, Yashwant; Nityanada, Rajaram; Odegova, Julia; Pen, Ue-Li; Peterson, Jeffrey; Roy, Jayanta; Sigurdson, Kris

2010-01-01T23:59:59.000Z

95

Small Scale Clustering of Late Forming Dark Matter  

E-Print Network (OSTI)

We perform a study of the non-linear clustering of matter in the Late Forming Dark Matter (LFDM) scenario in which dark matter results from the transition of non-minimally coupled scalar field from radiation to collisionless matter. A distinct feature of this model is the presence of a damped oscillatory cut-off in the linear matter power spectrum at small scales. We use a suite of high-resolution N-body simulations to study the imprints of LFDM on the non-linear matter power spectrum, the halo mass function and the halo density profiles. The model satisfies high-redshift matter power spectrum constraints from Lyman-$\\alpha$ forest measurements. We find suppressed abundance of low mass halos ($\\sim 10^{9}-10^{10}$ h$^{-1}$ M$_\\odot$) at all redshifts compared to a vanilla $\\Lambda$CDM model. Furthermore, in this mass range we find significant deviations with respect to predictions from the Sheth-Tormen mass function. Halos with mass $M\\gtrsim 10^{11}$ h$^{-1}$ M$_\\odot$ show minor departures of the density pr...

Agarwal, Shankar; Das, Subinoy; Rasera, Yann

2014-01-01T23:59:59.000Z

96

Quantum Condensed Matter | More Science | ORNL  

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

Quantum Condensed Matter SHARE Quantum Condensed Matter Neutron scattering is a uniquely powerful probe for measuring the structure and dynamics of condensed matter. As such it is...

97

Quantum Condensed Matter | Neutron Science | ORNL  

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

Quantum Condensed Matter SHARE Quantum Condensed Matter Neutron scattering is a uniquely powerful probe for measuring the structure and dynamics of condensed matter. As such it is...

98

NREL Uses Computing Power to Investigate Tidal Power (Fact Sheet), Innovation: The Spectrum of Clean Energy Innovation, NREL (National Renewable Energy Laboratory)  

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

Uses Computing Power to Uses Computing Power to Investigate Tidal Power Researchers at the National Renewable Energy Laboratory (NREL) have applied their knowledge of wind flow and turbulence to simulations of underwater tidal turbines. Inspired by similar simulations of wind turbine arrays, NREL researchers used their wind expertise, a supercomputer, and large-eddy simulation to study how the placement of turbines affects the power production of an underwater tidal turbine array. As tides ebb and flow, they create water currents that carry a significant amount of kinetic energy. To capture this energy, several companies are developing and deploying devices known as horizontal-axis tidal turbines, which resemble small wind turbines. These devices can be arranged in an array of multiple turbines to maximize the energy extracted in tidal

99

Advanced Condenser Boosts Geothermal Power Plant Output (Fact Sheet), The Spectrum of Clean Energy Innovation, NREL (National Renewable Energy Laboratory)  

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

Geothermal resources-the steam and water that lie below the earth's surface-have the Geothermal resources-the steam and water that lie below the earth's surface-have the potential to supply vast amounts of clean energy. But continuing to produce geothermal power efficiently and inexpensively can require innovative adjustments to the technology used to process it. Located in the Mayacamas Mountains of northern California, The Geysers is the world's larg- est geothermal complex. Encompassing 45 square miles along the Sonoma and Lake County border, the complex harnesses natural steam reservoirs to create clean renewable energy that accounts for one-fifth of the green power produced in California. In the late 1990s, the pressure of geothermal steam at The Geysers was falling, reducing the output of its power plants. NREL teamed with Pacific

100

Power spectrum estimates of high frequency noise generated by high impedance arcing faults on distribution systems / by Thomas James Talley  

E-Print Network (OSTI)

. 1 See Ap- pendix A. 2 Recor- DC-80kHz +20v . 57vpk 10vpk 1 47db der See Ap- pendix A. 3 Other measurement considerations involved the frequency response of the relaying Current Transformer (CT's) at power system substations which were... . 1 See Ap- pendix A. 2 Recor- DC-80kHz +20v . 57vpk 10vpk 1 47db der See Ap- pendix A. 3 Other measurement considerations involved the frequency response of the relaying Current Transformer (CT's) at power system substations which were...

Talley, Thomas James

2012-06-07T23:59:59.000Z

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101

BROADBAND JET EMISSION IN YOUNG AND POWERFUL RADIO SOURCES: THE CASE OF THE COMPACT STEEP SPECTRUM QUASAR 3C 186  

SciTech Connect

We present the X-ray analysis of a deep ({approx}200 ks) Chandra observation of the compact steep spectrum radio-loud quasar 3C 186 (z = 1.06) and investigate the contribution of the unresolved radio jet to the total X-ray emission. The spectral analysis is not conclusive on the origin of the bulk of the X-ray emission. In order to examine the jet contribution to the X-ray flux, we model the quasar spectral energy distribution, adopting several scenarios for the jet emission. For the values of the main physical parameters favored by the observables, a dominant role of the jet emission in the X-ray band is ruled out when a single-zone (leptonic) scenario is adopted, even including the contribution of the external photon fields as seed photons for inverse Compton emission. We then consider a structured jet, with the blazar component that-although not directly visible in the X-ray band-provides an intense field of seed synchrotron photons Compton-scattered by electrons in a mildly relativistic knot. In this case, the whole X-ray emission can be accounted for if we assume a blazar luminosity within the range observed from flat spectrum radio quasars. The X-ray radiative efficiency of such a (structured) jet is intimately related to the presence of a complex velocity structure. The jet emission can provide a significant contribution in X-rays if it decelerates within the host galaxy on kiloparsec scales. We discuss the implications of this model in terms of jet dynamics and interaction with the ambient medium.

Migliori, Giulia; Siemiginowska, Aneta [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Celotti, Annalisa, E-mail: migliori@cfa.harvard.edu [SISSA, Via Bonomea 265, I-34136 Trieste (Italy)

2012-04-20T23:59:59.000Z

102

Measurement of particulate matter and trace elements from a coal-fired power plant with electrostatic precipitators equipped the low temperature economizer  

Science Journals Connector (OSTI)

Abstract The particulate matter and trace elements from a 660 MW coal-fired power plant boiler which equipped with a novel electrostatic precipitator were sampled and analyzed. To promote the thermal efficiency of power plants, a low temperature economizer was installed at the inlet of electrostatic precipitator to collect the heat generated from flue gas. The low temperature economizer can reduce flue gas temperature, and then affect the operation of electrostatic precipitator. Therefore, this experiment was carried out to investigate the collection characteristics of this novel electrostatic precipitator on particulate matter. In addition, the distribution of trace elements in solid combustion residues was also studied. The results indicate that the low temperature economizer can markedly decrease the amount of particulate matter at the outlet of electrostatic precipitator. The collection efficiency of electrostatic precipitator on particulate matter is significantly improved by the low temperature economizer, whereby the collection efficiencies of PM2.5 and PM1.0 can reach 99.7% and 99.2%, respectively. Most of the trace elements remain in the fly ash collected by the electrostatic precipitator, and less than 10% remain in the bottom ash, but very rare emit from the electrostatic precipitator. The low temperature economizer not only reduces the emission of particulate matter, but also diminishes the emissions of trace elements in flue gas. The enrichment characteristics of trace elements in submicron particles were also studied.

Chao Wang; Xiaowei Liu; Dong Li; Junping Si; Bo Zhao; Minghou Xu

2014-01-01T23:59:59.000Z

103

Dark Energy - Dark Matter Unification: Generalized Chaplygin Gas Model  

E-Print Network (OSTI)

We review the main features of the generalized Chaplygin gas (GCG) proposal for unification of dark energy and dark matter and discuss how it admits an unique decomposition into dark energy and dark matter components once phantom-like dark energy is excluded. In the context of this approach we consider structure formation and show that unphysical oscillations or blow-up in the matter power spectrum are not present. Moreover, we demonstrate that the dominance of dark energy occurs about the time when energy density fluctuations start evolving away from the linear regime.

Orfeu Bertolami

2005-04-14T23:59:59.000Z

104

Evaluation of the Emission, Transport, and Deposition of Mercury, Arsenic, and Fine Particulate Matter From Coal-Based Power Plants in the Ohio River Valley  

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

Kevin crist Kevin crist Principal Investigator Ohio University Research and Technology Center Athens, OH 45701 740-593-4751 cristk@ohiou.edu Environmental and Water Resources Evaluation of thE Emission, transport, and dEposition of mErcury, arsEnic, and finE particulatE mattEr from coal-BasEd powEr plants in thE ohio rivEr vallEy rEgion Background The U.S. Department of Energy's National Energy Technology Laboratory (NETL) has established an aggressive research initiative to address the technical and scientific issues surrounding the impact of coal-based power systems on ambient levels of fine particulate matter (PM 2.5 ), nitrogen oxides (NO X ), mercury/air toxics, and acid gases. Regulatory drivers such as the 1990 Clean Air Act Amendments, the 1997 revised National Ambient Air Quality Standards, and the 2005 Clean Air

105

The effect of non-Gaussianity on error predictions for the Epoch of Reionization (EoR) 21-cm power spectrum  

E-Print Network (OSTI)

The EoR 21-cm signal is expected to become increasingly non-Gaussian as reionization proceeds. We have used semi-numerical simulations to study how this affects the error predictions for the EoR 21-cm power spectrum. We expect $SNR=\\sqrt{N_k}$ for a Gaussian random field where $N_k$ is the number of Fourier modes in each $k$ bin. We find that the effect of non-Gaussianity on the $SNR$ does not depend on $k$. Non-Gaussianity is important at high $SNR$ where it imposes an upper limit $[SNR]_l$. It is not possible to achieve $SNR > [SNR]_l$ even if $N_k$ is increased. The value of $[SNR]_l$ falls as reionization proceeds, dropping from $\\sim 500$ at $\\bar{x}_{{\\rm HI}} = 0.8-0.9$ to $\\sim 10$ at $\\bar{x}_{{\\rm HI}} = 0.15$. For $SNR \\ll [SNR]_l$ we find $SNR = \\sqrt{N_k}/A$ with $A \\sim 1.5 - 2.5$, roughly consistent with the Gaussian prediction. We present a fitting formula for the $SNR$ as a function of $N_k$, with two parameters $A$ and $[SNR]_l$ that have to be determined using simulations. Our results are r...

Mondal, Rajesh; Majumdar, Suman; Bera, Apurba; Acharyya, Ayan

2014-01-01T23:59:59.000Z

106

Constraints on particle dark matter from cosmic-ray antiprotons  

E-Print Network (OSTI)

Cosmic-ray antiprotons represent an important channel for dark matter indirect-detection studies. Current measurements of the antiproton flux at the top of the atmosphere and theoretical determinations of the secondary antiproton production in the Galaxy are in good agreement, with no manifest deviation which could point to an exotic contribution in this channel. Therefore, antiprotons can be used as a powerful tool for constraining particle dark matter properties. By using the spectrum of PAMELA data from 50 MV to 180 GV in rigidity, we derive bounds on the dark matter annihilation cross section (or decay rate, for decaying dark matter) for the whole spectrum of dark matter annihilation (decay) channels and under different hypotheses of cosmic-rays transport in the Galaxy and in the heliosphere. For typical models of galactic propagation, the constraints are significantly strong, setting a lower bound on the dark matter mass of a "thermal" relic at about 50 -- 90 GeV for hadronic annihilation channels. These bounds are enhanced to about 150 GeV on the dark matter mass, when large cosmic-rays confinement volumes in the Galaxy are considered, and are reduced to 4-5 GeV for annihilation to light quarks (no bound for heavy-quark production) when the confinement volume is small. Bounds for dark matter lighter than few tens of GeV are due to the low energy part of the PAMELA spectrum, an energy region where solar modulation is relevant: to this aim, we have implemented a detailed solution of the transport equation in the heliosphere, which allowed us not only to extend bounds to light dark matter, but also to determine the uncertainty on the constraints arising from solar modulation modeling. Finally, we estimate the impact of soon-to-come AMS-02 data on the antiproton constraints.

N. Fornengo; L. Maccione; A. Vittino

2013-12-12T23:59:59.000Z

107

Constraints on particle dark matter from cosmic-ray antiprotons  

E-Print Network (OSTI)

Cosmic-ray antiprotons represent an important channel for dark matter indirect-detection studies. Current measurements of the antiproton flux at the top of the atmosphere and theoretical determinations of the secondary antiproton production in the Galaxy are in good agreement, with no manifest deviation which could point to an exotic contribution in this channel. Therefore, antiprotons can be used as a powerful tool for constraining particle dark matter properties. By using the spectrum of PAMELA data from 50 MV to 180 GV in rigidity, we derive bounds on the dark matter annihilation cross section (or decay rate, for decaying dark matter) for the whole spectrum of dark matter annihilation (decay) channels and under different hypotheses of cosmic-rays transport in the Galaxy and in the heliosphere. For typical models of galactic propagation, the constraints are significantly strong, setting a lower bound on the dark matter mass of a "thermal" relic at about 50-90 GeV for hadronic annihilation channels. These bounds are enhanced to about 150 GeV on the dark matter mass, when large cosmic-rays confinement volumes in the Galaxy are considered, and are reduced to 4-5 GeV for annihilation to light quarks (no bound for heavy-quark production) when the confinement volume is small. Bounds for dark matter lighter than few tens of GeV are due to the low energy part of the PAMELA spectrum, an energy region where solar modulation is relevant: to this aim, we have implemented a detailed solution of the transport equation in the heliosphere, which allowed us not only to extend bounds to light dark matter, but also to determine the uncertainty on the constraints arising from solar modulation modeling. Finally, we estimate the impact of soon-to-come AMS-02 data on the antiproton constraints.

N. Fornengo; L. Maccione; A. Vittino

2015-01-30T23:59:59.000Z

108

Injection Locking Techniques for Spectrum Analysis  

SciTech Connect

Wideband spectrum analysis supports future communication systems that reconfigure and adapt to the capacity of the spectral environment. While test equipment manufacturers offer wideband spectrum analyzers with excellent sensitivity and resolution, these spectrum analyzers typically cannot offer acceptable size, weight, and power (SWAP). CMOS integrated circuits offer the potential to fully integrate spectrum analysis capability with analog front-end circuitry and digital signal processing on a single chip. Unfortunately, CMOS lacks high-Q passives and wideband resonator tunability that is necessary for heterodyne implementations of spectrum analyzers. As an alternative to the heterodyne receiver architectures, two nonlinear methods for performing wideband, low-power spectrum analysis are presented. The first method involves injecting the spectrum of interest into an array of injection-locked oscillators. The second method employs the closed loop dynamics of both injection locking and phase locking to independently estimate the injected frequency and power.

Gathma, Timothy D.; Buckwalter, James F. [Department of Electrical and Computer Engineering, University of California San Diego, 9500 Gilman Dr., La Jolla, CA 9209 (United States)

2011-04-19T23:59:59.000Z

109

Antihelium from dark matter  

Science Journals Connector (OSTI)

Cosmic-ray antinuclei provide a promising discovery channel for the indirect detection of particle dark matter. Hadron showers produced by the pair annihilation or decay of Galactic dark matter generate antinucleons which can in turn form light antinuclei. Previous studies have only focused on the spectrum and flux of low energy antideuterons which, although very rarely, are occasionally also produced by cosmic-ray spallation. Heavier elements (A?3) have instead entirely negligible astrophysical background and a primary yield from dark matter which could be detectable by future experiments. Using a Monte Carlo event generator and an event-by-event phase space analysis, we compute, for the first time, the production spectrum of He¯3 and H¯3 for dark matter annihilating or decaying to bb¯ and W+W? final states. We then employ a semianalytic model of interstellar and heliospheric propagation to calculate the He¯3 flux as well as to provide tools to relate the antihelium spectrum corresponding to an arbitrary antideuteron spectrum. Finally, we discuss prospects for current and future experiments, including GAPS and AMS-02.

Eric Carlson; Adam Coogan; Tim Linden; Stefano Profumo; Alejandro Ibarra; Sebastian Wild

2014-04-08T23:59:59.000Z

110

The First Billion Years of a Warm Dark Matter Universe  

E-Print Network (OSTI)

We present results of cosmological N-body hydrodynamic chemistry simulations of primordial structure growth and evolution in a scenario with warm dark matter (WDM) having a mass of 3keV and compare with a model consisting of standard cold dark matter (CDM). We focus on the high-redshift universe ($z>6$), where the structure formation process should better reflect the primordial (linear) differences in terms of matter power spectrum. We find that early epochs are exceptional probes of the dark-matter nature. Non-linear CDM and WDM power spectra differ by up to 2 dex at early times and show spreads of factor of a few persisting in the whole first Gyr. Primordial WDM objects with masses $\\lesssim 10^8\\,\\rm M_\\odot$ are less abundant by $\\gtrsim 1\\,\\rm dex$, both in terms of dark matter and of baryon content. Runaway molecular cooling in primordial WDM mini-haloes results severely inhibited due to the damping of power at large $k$ modes. As a consequence, the cosmic (population III and II-I) star formation activi...

Maio, Umberto

2014-01-01T23:59:59.000Z

111

EVALUATION OF THE EMISSION, TRANSPORT, AND DEPOSITION OF MERCURY, FINE PARTICULATE MATTER, AND ARSENIC FROM COAL-BASED POWER PLANTS IN THE OHIO RIVER VALLEY REGION  

SciTech Connect

Ohio University, in collaboration with CONSOL Energy, Advanced Technology Systems, Inc. (ATS) and Atmospheric and Environmental Research, Inc. (AER) as subcontractors, is evaluating the impact of emissions from coal-fired power plants in the Ohio River Valley region as they relate to the transport and deposition of mercury, arsenic, and associated fine particulate matter. This evaluation will involve two interrelated areas of effort: ambient air monitoring and regional-scale modeling analysis. The scope of work for the ambient air monitoring will include the deployment of a surface air monitoring (SAM) station in southeastern Ohio. The SAM station will contain sampling equipment to collect and measure mercury (including speciated forms of mercury and wet and dry deposited mercury), arsenic, particulate matter (PM) mass, PM composition, and gaseous criteria pollutants (CO, NOx, SO{sub 2}, O{sub 3}, etc.). Laboratory analysis of time-integrated samples will be used to obtain chemical speciation of ambient PM composition and mercury in precipitation. Near-real-time measurements will be used to measure the ambient concentrations of PM mass and all gaseous species including Hg{sup 0} and RGM. Approximately 18 months of field data will be collected at the SAM site to validate the proposed regional model simulations for episodic and seasonal model runs. The ambient air quality data will also provide mercury, arsenic, and fine particulate matter data that can be used by Ohio Valley industries to assess performance on multi-pollutant control systems. The scope of work for the modeling analysis will include (1) development of updated inventories of mercury and arsenic emissions from coal-fired power plants and other important sources in the modeled domain; (2) adapting an existing 3-D atmospheric chemical transport model to incorporate recent advancements in the understanding of mercury transformations in the atmosphere; (3) analyses of the flux of Hg{sup 0}, RGM, arsenic, and fine particulate matter in the different sectors of the study region to identify key transport mechanisms; (4) comparison of cross correlations between species from the model results to observations in order to evaluate characteristics of specific air masses associated with long-range transport from a specified source region; and (5) evaluation of the sensitivity of these correlations to emissions from regions along the transport path. This will be accomplished by multiple model runs with emissions simulations switched on and off from the various source regions. To the greatest extent possible, model results will also be compared to field data collected at other air monitoring sites in the Ohio Valley Region, operated independently of this project. These sites may include (1) the DOE National Energy Technology Laboratory's monitoring site at its suburban Pittsburgh, PA facility; (2) sites in Pittsburgh (Lawrenceville) PA and Holbrook, PA operated by ATS; (3) sites in Steubenville, OH and Pittsburgh, PA operated by U.S. EPA and/or its contractors; and (4) sites operated by State or local air regulatory agencies. Field verification of model results and predictions will provide critical information for the development of cost effective air pollution control strategies by the coal-fired power plants in the Ohio River Valley region.

Kevin Crist

2004-04-02T23:59:59.000Z

112

EVALUATION OF THE EMISSION, TRANSPORT, AND DEPOSITION OF MERCURY, FINE PARTICULATE MATTER, AND ARSENIC FROM COAL-BASED POWER PLANTS IN THE OHIO RIVER VALLEY REGION  

SciTech Connect

Ohio University, in collaboration with CONSOL Energy, Advanced Technology Systems, Inc (ATS) and Atmospheric and Environmental Research, Inc. (AER) as subcontractors, is evaluating the impact of emissions from coal-fired power plants in the Ohio River Valley region as they relate to the transport and deposition of mercury, arsenic, and associated fine particulate matter. This evaluation will involve two interrelated areas of effort: ambient air monitoring and regional-scale modeling analysis. The scope of work for the ambient air monitoring will include the deployment of a surface air monitoring (SAM) station in southeastern Ohio. The SAM station will contain sampling equipment to collect and measure mercury (including speciated forms of mercury and wet and dry deposited mercury), arsenic, particulate matter (PM) mass, PM composition, and gaseous criteria pollutants (CO, NO{sub x}, SO{sub 2}, O{sub 3}, etc.). Laboratory analysis of time-integrated samples will be used to obtain chemical speciation of ambient PM composition and mercury in precipitation. Near-real-time measurements will be used to measure the ambient concentrations of PM mass and all gaseous species including Hg{sup 0} and RGM. Approximately of 18 months of field data will be collected at the SAM site to validate the proposed regional model simulations for episodic and seasonal model runs. The ambient air quality data will also provide mercury, arsenic, and fine particulate matter data that can be used by Ohio Valley industries to assess performance on multi-pollutant control systems. The scope of work for the modeling analysis will include (1) development of updated inventories of mercury and arsenic emissions from coal plants and other important sources in the modeled domain; (2) adapting an existing 3-D atmospheric chemical transport model to incorporate recent advancements in the understanding of mercury transformations in the atmosphere; (3) analyses of the flux of Hg{sup 0}, RGM, arsenic, and fine particulate matter in the different sectors of the study region to identify key transport mechanisms; (4) comparison of cross correlations between species from the model results to observations in order to evaluate characteristics of specific air masses associated with long-range transport from a specified source region; and (5) evaluation of the sensitivity of these correlations to emissions from regions along the transport path. This will be accomplished by multiple model runs with emissions simulations switched on and off from the various source regions. To the greatest extent possible, model results will also be compared to field data collected at other air monitoring sites in the Ohio Valley region, operated independently of this project. These sites may include (1) the DOE National Energy Technologies Laboratory's monitoring site at its suburban Pittsburgh, PA facility; (2) sites in Pittsburgh (Lawrenceville) PA and Holbrook, PA operated by ATS; (3) sites in Steubenville, OH and Pittsburgh, PA operated by U.S. EPA and/or its contractors; and (4) sites operated by State or local air regulatory agencies. Field verification of model results and predictions will provide critical information for the development of cost effective air pollution control strategies by the coal-fired power plants in the Ohio River Valley region.

Kevin Crist

2005-04-02T23:59:59.000Z

113

EVALUATION OF THE EMISSION, TRANSPORT, AND DEPOSITION OF MERCURY, FINE PARTICULATE MATTER, AND ARSENIC FROM COAL-BASED POWER PLANTS IN THE OHIO RIVER VALLEY REGION  

SciTech Connect

Ohio University, in collaboration with CONSOL Energy, Advanced Technology Systems, Inc (ATS) and Atmospheric and Environmental Research, Inc. (AER) as subcontractors, is evaluating the impact of emissions from coal-fired power plants in the Ohio River Valley region as they relate to the transport and deposition of mercury, arsenic, and associated fine particulate matter. This evaluation will involve two interrelated areas of effort: ambient air monitoring and regional-scale modeling analysis. The scope of work for the ambient air monitoring will include the deployment of a surface air monitoring (SAM) station in southeastern Ohio. The SAM station will contain sampling equipment to collect and measure mercury (including speciated forms of mercury and wet and dry deposited mercury), arsenic, particulate matter (PM) mass, PM composition, and gaseous criteria pollutants (CO, NO{sub x}, SO{sub 2}, O{sub 3}, etc.). Laboratory analysis of time-integrated samples will be used to obtain chemical speciation of ambient PM composition and mercury in precipitation. Near-real-time measurements will be used to measure the ambient concentrations of PM mass and all gaseous species including Hg{sup 0} and RGM. Approximately of 18 months of field data will be collected at the SAM site to validate the proposed regional model simulations for episodic and seasonal model runs. The ambient air quality data will also provide mercury, arsenic, and fine particulate matter data that can be used by Ohio Valley industries to assess performance on multi-pollutant control systems. The scope of work for the modeling analysis will include (1) development of updated inventories of mercury and arsenic emissions from coal plants and other important sources in the modeled domain; (2) adapting an existing 3-D atmospheric chemical transport model to incorporate recent advancements in the understanding of mercury transformations in the atmosphere; (3) analyses of the flux of Hg{sup 0}, RGM, arsenic, and fine particulate matter in the different sectors of the study region to identify key transport mechanisms; (4) comparison of cross correlations between species from the model results to observations in order to evaluate characteristics of specific air masses associated with long-range transport from a specified source region; and (5) evaluation of the sensitivity of these correlations to emissions from regions along the transport path. This will be accomplished by multiple model runs with emissions simulations switched on and off from the various source regions. To the greatest extent possible, model results will also be compared to field data collected at other air monitoring sites in the Ohio Valley Region, operated independently of this project. These sites may include (1) the DOE National Energy Technologies Laboratory's monitoring site at its suburban Pittsburgh, PA facility; (2) sites in Pittsburgh (Lawrenceville) PA and Holbrook, PA operated by ATS; (3) sites in Steubenville, OH and Pittsburgh, PA operated by U.S. EPA and/or its contractors; and (4) sites operated by State or local air regulatory agencies. Field verification of model results and predictions will provide critical information for the development of cost effective air pollution control strategies by the coal-fired power plants in the Ohio River Valley Region.

Kevin Crist

2003-10-02T23:59:59.000Z

114

Evaluation of the Emission, Transport, and Deposition of Mercury, Fine Particulate Matter, and Arsenic from Coal-Based Power Plants in the Ohio River Valley Region  

SciTech Connect

As stated in the proposal: Ohio University, in collaboration with CONSOL Energy, Advanced Technology Systems, Inc (ATS) and Atmospheric and Environmental Research, Inc. (AER) as subcontractors, is evaluating the impact of emissions from coal-fired power plants in the Ohio River Valley region as they relate to the transport and deposition of mercury, arsenic, and associated fine particulate matter. This evaluation will involve two interrelated areas of effort: ambient air monitoring and regional-scale modeling analysis. The scope of work for the ambient air monitoring will include the deployment of a surface air monitoring (SAM) station in southeastern Ohio. The SAM station will contain sampling equipment to collect and measure mercury (including speciated forms of mercury and wet and dry deposited mercury), arsenic, particulate matter (PM) mass, PM composition, and gaseous criteria pollutants (CO, NO{sub x}, SO{sub 2}, O{sub 3}, etc.). Laboratory analysis of time-integrated samples will be used to obtain chemical speciation of ambient PM composition and mercury in precipitation. Near-real-time measurements will be used to measure the ambient concentrations of PM mass and all gaseous species including Hg0 and RGM. Approximately 18 months of field data will be collected at the SAM site to validate the proposed regional model simulations for episodic and seasonal model runs. The ambient air quality data will also provide mercury, arsenic, and fine particulate matter data that can be used by Ohio Valley industries to assess performance on multi-pollutant control systems. The scope of work for the modeling analysis will include (1) development of updated inventories of mercury and arsenic emissions from coal plants and other important sources in the modeled domain; (2) adapting an existing 3-D atmospheric chemical transport model to incorporate recent advancements in the understanding of mercury transformations in the atmosphere; (3) analyses of the flux of Hg{sup 0}, RGM, arsenic, and fine particulate matter in the different sectors of the study region to identify key transport mechanisms; (4) comparison of cross correlations between species from the model results to observations in order to evaluate characteristics of specific air masses associated with long-range transport from a specified source region; and (5) evaluation of the sensitivity of these correlations to emissions from regions along the transport path. This will be accomplished by multiple model runs with emissions simulations switched on and off from the various source regions. To the greatest extent possible, model results will also be compared to field data collected at other air monitoring sites in the Ohio Valley region, operated independently of this project. These sites may include (1) the DOE National Energy Technologies Laboratory's monitoring site at its suburban Pittsburgh, PA facility; (2) sites in Pittsburgh (Lawrenceville) PA and Holbrook, PA operated by ATS; (3) sites in Steubenville, OH and Pittsburgh, PA operated by the USEPA and/or its contractors; and (4) sites operated by State or local air regulatory agencies. Field verification of model results and predictions will provide critical information for the development of cost effective air pollution control strategies by the coal-fired power plants in the Ohio River Valley region.

Kevin Crist

2006-04-02T23:59:59.000Z

115

EVALUATION OF THE EMISSION, TRANSPORT, AND DEPOSITION OF MERCURY, FINE PARTICULATE MATTER, AND ARSENIC FROM COAL-BASED POWER PLANTS IN THE OHIO RIVER VALLEY REGION  

SciTech Connect

Ohio University, in collaboration with CONSOL Energy, Advanced Technology Systems, Inc (ATS) and Atmospheric and Environmental Research, Inc. (AER) as subcontractors, is evaluating the impact of emissions from coal-fired power plants in the Ohio River Valley region as they relate to the transport and deposition of mercury, arsenic, and associated fine particulate matter. This evaluation will involve two interrelated areas of effort: ambient air monitoring and regional-scale modeling analysis. The scope of work for the ambient air monitoring will include the deployment of a surface air monitoring (SAM) station in southeastern Ohio. The SAM station will contain sampling equipment to collect and measure mercury (including speciated forms of mercury and wet and dry deposited mercury), arsenic, particulate matter (PM) mass, PM composition, and gaseous criteria pollutants (CO, NOx, SO{sub 2}, O{sub 3}, etc.). Laboratory analysis of time-integrated samples will be used to obtain chemical speciation of ambient PM composition and mercury in precipitation. Near-real-time measurements will be used to measure the ambient concentrations of PM mass and all gaseous species including Hg{sup 0} and RGM. Approximately of 18 months of field data will be collected at the SAM site to validate the proposed regional model simulations for episodic and seasonal model runs. The ambient air quality data will also provide mercury, arsenic, and fine particulate matter data that can be used by Ohio Valley industries to assess performance on multi-pollutant control systems. The scope of work for the modeling analysis will include (1) development of updated inventories of mercury and arsenic emissions from coal plants and other important sources in the modeled domain; (2) adapting an existing 3-D atmospheric chemical transport model to incorporate recent advancements in the understanding of mercury transformations in the atmosphere; (3) analyses of the flux of Hg{sup 0}, RGM, arsenic, and fine particulate matter in the different sectors of the study region to identify key transport mechanisms; (4) comparison of cross correlations between species from the model results to observations in order to evaluate characteristics of specific air masses associated with long-range transport from a specified source region; and (5) evaluation of the sensitivity of these correlations to emissions from regions along the transport path. This will be accomplished by multiple model runs with emissions simulations switched on and off from the various source regions. To the greatest extent possible, model results will also be compared to field data collected at other air monitoring sites in the Ohio Valley region, operated independently of this project. These sites may include (1) the DOE National Energy Technologies Laboratory's monitoring site at its suburban Pittsburgh, PA facility; (2) sites in Pittsburgh (Lawrenceville) PA and Holbrook, PA operated by ATS; (3) sites in Steubenville, OH and Pittsburgh, PA operated by U.S. EPA and/or its contractors; and (4) sites operated by State or local air regulatory agencies. Field verification of model results and predictions will provide critical information for the development of cost effective air pollution control strategies by the coal-fired power plants in the Ohio River Valley region.

Kevin Crist

2004-10-02T23:59:59.000Z

116

Evaluation of the Emission, Transport, and Deposition of Mercury, Fine Particulate Matter, and Arsenic from Coal-Based Power Plants in the Ohio River Valley Region  

SciTech Connect

Ohio University, in collaboration with CONSOL Energy, Advanced Technology Systems, Inc (ATS) and Atmospheric and Environmental Research, Inc. (AER) as subcontractors, is evaluating the impact of emissions from coal-fired power plants in the Ohio River Valley region as they relate to the transport and deposition of mercury, arsenic, and associated fine particulate matter. This evaluation will involve two interrelated areas of effort: ambient air monitoring and regional-scale modeling analysis. The scope of work for the ambient air monitoring will include the deployment of a surface air monitoring (SAM) station in southeastern Ohio. The SAM station will contain sampling equipment to collect and measure mercury (including speciated forms of mercury and wet and dry deposited mercury), arsenic, particulate matter (PM) mass, PM composition, and gaseous criteria pollutants (CO, NOx, SO{sub 2}, O{sub 3}, etc.). Laboratory analysis of time-integrated samples will be used to obtain chemical speciation of ambient PM composition and mercury in precipitation. Near-real-time measurements will be used to measure the ambient concentrations of PM mass and all gaseous species including Hg{sup 0} and RGM. Approximately of 18 months of field data will be collected at the SAM site to validate the proposed regional model simulations for episodic and seasonal model runs. The ambient air quality data will also provide mercury, arsenic, and fine particulate matter data that can be used by Ohio Valley industries to assess performance on multi-pollutant control systems. The scope of work for the modeling analysis will include (1) development of updated inventories of mercury and arsenic emissions from coal plants and other important sources in the modeled domain; (2) adapting an existing 3-D atmospheric chemical transport model to incorporate recent advancements in the understanding of mercury transformations in the atmosphere; (3) analyses of the flux of Hg0, RGM, arsenic, and fine particulate matter in the different sectors of the study region to identify key transport mechanisms; (4) comparison of cross correlations between species from the model results to observations in order to evaluate characteristics of specific air masses associated with long-range transport from a specified source region; and (5) evaluation of the sensitivity of these correlations to emissions from regions along the transport path. This will be accomplished by multiple model runs with emissions simulations switched on and off from the various source regions. To the greatest extent possible, model results will also be compared to field data collected at other air monitoring sites in the Ohio Valley region, operated independently of this project. These sites may include (1) the DOE National Energy Technologies Laboratory's monitoring site at its suburban Pittsburgh, PA facility; (2) sites in Pittsburgh (Lawrenceville) PA and Holbrook, PA operated by ATS; (3) sites in Steubenville, OH and Pittsburgh, PA operated by U.S. EPA and/or its contractors; and (4) sites operated by State or local air regulatory agencies. Field verification of model results and predictions will provide critical information for the development of cost effective air pollution control strategies by the coal-fired power plants in the Ohio River Valley region.

Kevin Crist

2005-10-02T23:59:59.000Z

117

Components Makeover Gives Concentrating Solar Power a Boost (Fact Sheet), The Spectrum of Clean Energy Innovation, NREL (National Renewable Energy Laboratory)  

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

Components Makeover Gives Components Makeover Gives Concentrating Solar Power a Boost Parabolic trough technology is the most mature of the various concentrating solar power (CSP) options. But scientists at the National Renewable Energy Laboratory (NREL) continue to make advances on trough systems through innovative research on various components in industrial partnerships with Acciona Solar Power, SkyFuel, Schott Solar, and others. The results are leading to improved system efficiencies and lower costs for CSP plants. Space Frames for Lower Costs To maximize the overall efficiency of the conventional glass-mirror trough system, NREL worked with Acciona Solar Power-then known as Solargenix Energy-to improve vari- ous system components. A key focus was the structural framework that holds the mirrors

118

NREL Helps Cool the Power Electronics in Electric Vehicles (Fact Sheet), The Spectrum of Clean Energy Innovation, NREL (National Renewable Energy Laboratory)  

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

Helps Cool the Power Helps Cool the Power Electronics in Electric Vehicles Researchers at the National Renewable Energy Laboratory (NREL) are developing and demonstrating innovative heat-transfer technologies for cooling power electronics devices in hybrid and electric vehicles. In collaboration with 3M and Wolverine Tube, Inc., NREL is using surface enhancements to dissipate heat more effectively, permitting a reduction in the size of power electronic systems and potentially reducing the overall costs of electric vehicles. Widespread use of advanced electric-drive vehicles-including electric vehicles (EVs) and hybrid electric vehicles (HEVs)-could revolutionize transportation and dramatically reduce U.S. oil consumption. Improving the cost and performance of these vehicles' electric-drive systems

119

NRELs Wind Powering America Team Helps Indiana Develop Wind Resources (Fact Sheet), Innovation: The Spectrum of Clean Energy Innovation, NREL (National Renewable Energy Laboratory)  

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

NREL's Wind Powering NREL's Wind Powering America Team Helps Indiana Develop Wind Resources How does a state advance, in just five years, from having no wind power to having more than 1000 megawatts (MW) of installed capacity? The Wind Powering America (WPA) initiative, based at the National Renewable Energy Laboratory (NREL), employs a state-focused approach that has helped accelerate wind energy deployment in many states. One such state is Indiana, which is now home to the largest wind plant east of the Mississippi. Since 1999, WPA has helped advance technology acceptance and wind energy deployment across the United States through the formation of state wind working groups (WWGs). The WWGs facilitate workshops, manage anemometer loan programs, conduct outreach, and

120

Power spectrum characteristics of body sway time series and velocity time series of the center of foot pressure during a static upright posture in preschool children  

Science Journals Connector (OSTI)

This study aimed to assess individual and gender differences in power spectra in the body sway time series and sway velocity time series during a static upright standing posture using 30 preschool children and...

S. Demura; T. Kitabayashi

2008-08-01T23:59:59.000Z

Note: This page contains sample records for the topic "matter power spectrum" 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.


121

Antihelium from Dark Matter  

E-Print Network (OSTI)

Cosmic-ray anti-nuclei provide a promising discovery channel for the indirect detection of particle dark matter. Hadron showers produced by the pair-annihilation or decay of Galactic dark matter generate anti-nucleons which can in turn form light anti-nuclei. Previous studies have only focused on the spectrum and flux of low energy antideuterons which, although very rarely, are occasionally also produced by cosmic-ray spallation. Heavier elements ($A\\geq3$) have instead entirely negligible astrophysical background and a primary yield from dark matter which could be detectable by future experiments. Using a Monte Carlo event generator and an event-by-event phase space analysis, we compute, for the first time, the production spectrum of \\antihe and \\antiT for dark matter annihilating or decaying to $b\\bar{b}$ and ${W^+}{W^-}$ final states. We then employ a semi-analytic model of interstellar and heliospheric propagation to calculate the \\antihe flux as well as to provide tools to relate the anti-helium spectrum...

Carlson, Eric; Linden, Tim; Profumo, Stefano; Ibarra, Alejandro; Wild, Sebastian

2014-01-01T23:59:59.000Z

122

When matter matters  

SciTech Connect

We study a recently proposed scenario for the early universe:Subluminal Galilean Genesis. We prove that without any other matter present in the spatially flat Friedmann universe, the perturbations of the Galileon scalar field propagate with a speed at most equal to the speed of light. This proof applies to all cosmological solutions — to the whole phase space. However, in a more realistic situation, when one includes any matter which is not directly coupled to the Galileon, there always exists a region of phase space where these perturbations propagate superluminally, indeed with arbitrarily high speed. We illustrate our analytic proof with numerical computations. We discuss the implications of this result for the possible UV completion of the model.

Easson, Damien A. [Department of Physics and School of Earth and Space Exploration and Beyond Center, Arizona State University, Tempe, AZ, 85287-1504 (United States); Sawicki, Ignacy [Institut für Theoretische Physik, Ruprecht-Karls-Universität Heidelberg Philosophenweg 16, 69120 Heidelberg (Germany); Vikman, Alexander, E-mail: easson@asu.edu, E-mail: ignacy.sawicki@uni-heidelberg.de, E-mail: alexander.vikman@cern.ch [CERN, Theory Division, CH-1211 Genève 23 (Switzerland)

2013-07-01T23:59:59.000Z

123

NREL Triples Previous Estimates of U.S. Wind Power Potential (Fact Sheet), The Spectrum of Clean Energy Innovation, NREL (National Renewable Energy Laboratory)  

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

Triples Previous Estimates of Triples Previous Estimates of U.S. Wind Power Potential The National Renewable Energy Laboratory (NREL) recently released new estimates of the U.S. potential for wind-generated electricity, using advanced wind mapping and validation techniques that triple previous estimates of the size of the nation's wind resources. The new study, conducted by NREL and AWS TruePower, finds that the contiguous 48 states have the potential to generate up to 37 million gigawatt-hours annually. In comparison, the total U.S. electricity generation from all sources was roughly 4 million gigawatt-hours in 2009. Detailed state-by-state estimates of wind energy potential for the United States show the estimated average wind speeds at an 80-meter height. The wind resource maps and estimates

124

AN X-RAY COOLING-CORE CLUSTER SURROUNDING A LOW-POWER COMPACT STEEP SPECTRUM RADIO SOURCE 1321+045  

SciTech Connect

We discovered an X-ray cluster in a Chandra observation of the compact steep spectrum (CSS) radio source 1321+045 (z = 0.263). CSS sources are thought to be young radio objects at the beginning of their evolution and can potentially test the cluster heating process. 1321+045 is a relatively low-luminosity source and its morphology consists of two radio lobes on the opposite sides of a radio core with no evidence for jets or hotspots. The optical emission line ratios are consistent with an interstellar medium dominated by active galactic nucleus photoionization with a small contribution from star formation, and no contributions from shocks. Based on these ratios, we classify 1321+045 as a low excitation galaxy (LEG) and suggest that its radioactivity is in a coasting phase. The X-ray emission associated with the radio source is detected with 36.1 {+-} 8.3 counts, but the origin of this emission is highly uncertain. The current X-ray image of the cluster does not show any signatures of a radio source impact on the cluster medium. Chandra detects the cluster emission at >3{sigma} level out to {approx}60'' (240 kpc). We obtain the best-fit beta model parameters of the surface brightness profile of {beta} = 0.58 {+-} 0.2 and a core radius of 9.4{sup +1.1}{sub -0.9} arcsec. The average temperature of the cluster is equal to kT = 4.4{sup +0.5}{sub -0.3} keV, with a temperature and cooling profile indicative of a cooling core. We measure the cluster luminosity L{sub (0.5-2{sub keV)}} = 3 Multiplication-Sign 10{sup 44} erg s{sup -1} and mass 1.5 Multiplication-Sign 10{sup 14} M{sub Sun}.

Kunert-Bajraszewska, M. [Torun Centre for Astronomy, Faculty of Physics, Astronomy and Informatics, NCU, Grudziacka 5, 87-100 Torun (Poland); Siemiginowska, A. [Harvard Smithsonian Center for Astrophysics, 60 Garden St, Cambridge, MA 02138 (United States); Labiano, A., E-mail: magda@astro.uni.torun.pl [Centro de Astrobiologia (CSIC-INTA), Carretera de Ajalvir km. 4, E-28850 Torrejon de Ardoz, Madrid (Spain)

2013-07-20T23:59:59.000Z

125

ADAPTIVE POWER CONTROL BY USING THE RECEIVED SNR AS A PROXY FOR DISTANCE TO OPTIMIZE THE SPECTRUM USAGE IN A COGNITIVE RADIO SYSTEMADAPTIVE POWER CONTROL BY USING THE RECEIVED SNR AS A PROXY FOR DISTANCE TO OPTIMIZE THE SPECTRUM USAGE IN A COGNITIVE RADIO SYSTEM.  

E-Print Network (OSTI)

??In this thesis work we have proposed an Adaptive Power Transmission scheme for Cognitive Radio. The proposed scheme estimates the distance between the primary user… (more)

Hussain, Rizwan

2009-01-01T23:59:59.000Z

126

Radiation, Matter and Energy What is light?  

E-Print Network (OSTI)

Radiation, Matter and Energy #12;What is light? #12;Light is an electromagnetic wave #12;Light the visible spectrum, blue light has higher energy than red light Within the electromagnetic spectrum, X-rays have the highest energy, followed by UV, visible light, IR, and radio Remember: Light is just one form

Shirley, Yancy

127

Matter & Energy Nanotechnology  

E-Print Network (OSTI)

to electrical energy in order to power electronic devices, these results point to an advantage in reducingSee Also: Matter & Energy Nanotechnology Materials Science Technology Energy Technology Civil of potential functionalities, ranging from single-nanowire lasers and LEDs to more complex devices

Espinosa, Horacio D.

128

Effects on the two-point correlation function from the coupling of quintessence to dark matter  

SciTech Connect

We investigate the effects of the nonminimal coupling between the scalar field dark energy (quintessence) and the dark matter on the two-point correlation function. It is well known that this coupling shifts the turnover scale as well as suppresses the amplitude of the matter power spectrum. However, these effects are too small to be observed when we limit the coupling strength to be consistent with observations. Since the coupling of quintessence to baryons is strongly constrained, species-dependent coupling may arise. This results in a baryon bias that is different from unity. Thus, we investigate the correlation function in this coupled model. We are able to observe the enhancement of the baryon acoustic oscillation (BAO) peak due to the increasing bias factor of baryon from this species-dependent coupling. In order to avoid the damping effect of the BAO signature in the matter power spectrum due to nonlinear clustering, we consider the coupling effect on the BAO bump in the linear regime. This provides an alternative method to constrain the coupling of dark energy to dark matter.

Lee, Seokcheon [Institute of Physics, Academia Sinica, Taipei, Taiwan 11529 (China); Leung Center for Cosmology and Particle Astrophysics, National Taiwan University, Taipei, Taiwan 10617 (China); Liu, G.-C. [Department of Physics, Tamkang University, Tamsui, Taipei County, Taiwan 251 (China); Institute of Astronomy and Astrophysics, Academia Sinica, Taipei, Taiwan 11529 (China); Ng, K.-W. [Institute of Physics, Academia Sinica, Taipei, Taiwan 11529 (China); Leung Center for Cosmology and Particle Astrophysics, National Taiwan University, Taipei, Taiwan 10617 (China); Institute of Astronomy and Astrophysics, Academia Sinica, Taipei, Taiwan 11529 (China)

2010-03-15T23:59:59.000Z

129

Dark Matters  

ScienceCinema (OSTI)

One of the greatest mysteries in the cosmos is that it is mostly dark.  Astronomers and particle physicists today are seeking to unravel the nature of this mysterious, but pervasive dark matter which has profoundly influenced the formation of structure in the universe.  I will describe the complex interplay between galaxy formation and dark matter detectability and review recent attempts to measure particle dark matter by direct and indirect means.

Joseph Silk

2010-01-08T23:59:59.000Z

130

Weak lensing and dark energy: The impact of dark energy on nonlinear dark matter clustering  

SciTech Connect

We examine the influence of percent-level dark energy corrections to the nonlinear matter power spectrum on constraints of the dark energy equation of state from future weak lensing probes. We explicitly show that a poor approximation (off by > or approx.10%) to the nonlinear corrections causes a > or approx. 1{sigma} bias on the determination of the dark energy equation of state. Future weak lensing surveys must therefore incorporate dark energy modifications to the nonlinear matter power spectrum accurate to the percent-level, to avoid introducing significant bias in their measurements. For the WMAP5 cosmology, the more accurate power spectrum is more sensitive to dark energy properties, resulting in a factor of 2 improvement in dark energy equation of state constraints. We explore the complementary constraints on dark energy from future weak lensing and supernova surveys. A space-based, Joint Dark Energy Mission-like survey measures the equation of state in five independent redshift bins to {approx}10%, while this improves to {approx}5% for a wide-field ground-based survey like the Large Synoptic Survey Telescope. These constraints are contingent upon our ability to control weak lensing systematic uncertainties to the sub-percent level.

Joudaki, Shahab; Cooray, Asantha; Holz, Daniel E. [Center for Cosmology, Department of Physics and Astronomy, University of California, Irvine, California 92697 (United States); Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

2009-07-15T23:59:59.000Z

131

Weak lensing and dark energy: The impact of dark energy on nonlinear dark matter clustering  

Science Journals Connector (OSTI)

We examine the influence of percent-level dark energy corrections to the nonlinear matter power spectrum on constraints of the dark energy equation of state from future weak lensing probes. We explicitly show that a poor approximation (off by ?10%) to the nonlinear corrections causes a ?1? bias on the determination of the dark energy equation of state. Future weak lensing surveys must therefore incorporate dark energy modifications to the nonlinear matter power spectrum accurate to the percent-level, to avoid introducing significant bias in their measurements. For the WMAP5 cosmology, the more accurate power spectrum is more sensitive to dark energy properties, resulting in a factor of 2 improvement in dark energy equation of state constraints. We explore the complementary constraints on dark energy from future weak lensing and supernova surveys. A space-based, Joint Dark Energy Mission-like survey measures the equation of state in five independent redshift bins to ?10%, while this improves to ?5% for a wide-field ground-based survey like the Large Synoptic Survey Telescope. These constraints are contingent upon our ability to control weak lensing systematic uncertainties to the sub-percent level.

Shahab Joudaki; Asantha Cooray; Daniel E. Holz

2009-07-08T23:59:59.000Z

132

Dark matter  

Science Journals Connector (OSTI)

...just how much dark matter in baryons...have lead to the discovery that a large component of the dark mass in groups...the highest-energy photons and the...to that of the discovery of the microwave...experiments assume the dark matter in the...c) Vacuum energy and the cosmological...

1999-01-01T23:59:59.000Z

133

Dark Matter Searches with GLAST  

E-Print Network (OSTI)

Indirect detection of particle dark matter relies upon pair annihilation of Weakly Interaction Massive Particles (WIMPs), which is complementary to the well known techniques of direct detection (WIMP-nucleus scattering) and collider production (WIMP pair production). Pair annihilation of WIMPs results in the production of gamma-rays, neutrinos, and anti-matter. Of the various experiments sensitive to indirect detection of dark matter, the Gamma-ray Large Area Space Telescope (GLAST) may play the most crucial role in the next few years. After launch in late 2007, The GLAST Large Area Telescope (LAT) will survey the gamma-ray sky in the energy range of 20MeV-300GeV. By eliminating charged particle background above 100 MeV, GLAST may be sensitive to as yet to be observed Milky Way dark matter subhalos, as well as WIMP pair annihilation spectral lines from the Milky Way halo. Discovery of gamma-ray signals from dark matter in the Milky Way would not only demonstrate the particle nature of dark matter; it would also open a new observational window on galactic dark matter substructure. Location of new dark matter sources by GLAST would dramatically alter the experimental landscape; ground based gamma ray telescopes could follow up on the new GLAST sources with precision measurements of the WIMP pair annihilation spectrum.

Lawrence Wai; GLAST LAT Collaboration

2007-01-31T23:59:59.000Z

134

Using Light to Control How X Rays Interact with Matter  

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

Using Light to Control How X Using Light to Control How X Rays Interact with Matter Using Light to Control How X Rays Interact with Matter Print Wednesday, 27 January 2010 00:00 Schemes that use one light pulse to manipulate interactions of another with matter are well developed in the visible-light regime where an optical control pulse influences how an optical probe pulse interacts with a medium. This approach has opened new research directions in fields like quantum computing and nonlinear optics, while also spawning entirely new research areas, such as electromagnetically induced transparency and slow light. However, it has been unclear whether similar optical control schemes could be used to modify how x rays interact with matter. In a dramatic breakthrough demonstration at the ALS, a Berkeley Lab-Argonne National Laboratory group has now used powerful visible-light lasers to render a nominally opaque material transparent to x rays. While x-ray transparency will have immediate applications at x-ray light sources, the important result is that the findings lay a foundation for a broader spectrum of applications.

135

Using Light to Control How X Rays Interact with Matter  

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

Using Light to Control How X Rays Interact with Matter Print Using Light to Control How X Rays Interact with Matter Print Schemes that use one light pulse to manipulate interactions of another with matter are well developed in the visible-light regime where an optical control pulse influences how an optical probe pulse interacts with a medium. This approach has opened new research directions in fields like quantum computing and nonlinear optics, while also spawning entirely new research areas, such as electromagnetically induced transparency and slow light. However, it has been unclear whether similar optical control schemes could be used to modify how x rays interact with matter. In a dramatic breakthrough demonstration at the ALS, a Berkeley Lab-Argonne National Laboratory group has now used powerful visible-light lasers to render a nominally opaque material transparent to x rays. While x-ray transparency will have immediate applications at x-ray light sources, the important result is that the findings lay a foundation for a broader spectrum of applications.

136

Using Light to Control How X Rays Interact with Matter  

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

Using Light to Control How X Rays Interact with Matter Print Using Light to Control How X Rays Interact with Matter Print Schemes that use one light pulse to manipulate interactions of another with matter are well developed in the visible-light regime where an optical control pulse influences how an optical probe pulse interacts with a medium. This approach has opened new research directions in fields like quantum computing and nonlinear optics, while also spawning entirely new research areas, such as electromagnetically induced transparency and slow light. However, it has been unclear whether similar optical control schemes could be used to modify how x rays interact with matter. In a dramatic breakthrough demonstration at the ALS, a Berkeley Lab-Argonne National Laboratory group has now used powerful visible-light lasers to render a nominally opaque material transparent to x rays. While x-ray transparency will have immediate applications at x-ray light sources, the important result is that the findings lay a foundation for a broader spectrum of applications.

137

Light-powering Escherichia coli with proteorhodopsin  

Science Journals Connector (OSTI)

...depletion experiment, Ed Delong (Massachusetts Institute...Relative power = = 8.3. The solar spectrum ( spectrum sun...equivalent to PR absorption from solar illumination...roughly three times the PR solar power absorption, see section...

Jessica M. Walter; Derek Greenfield; Carlos Bustamante; Jan Liphardt

2007-01-01T23:59:59.000Z

138

Effective growth of matter density fluctuations in the running LCDM and LXCDM models  

E-Print Network (OSTI)

We investigate the matter density fluctuations \\delta\\rho/\\rho for two dark energy (DE) models in the literature in which the cosmological term \\Lambda is a running parameter. In the first model, the running LCDM model, matter and DE exchange energy, whereas in the second model, the LXCDM model, the total DE and matter components are conserved separately. The LXCDM model was proposed as an interesting solution to the cosmic coincidence problem. It includes an extra dynamical component, the "cosmon" X, which interacts with the running \\Lambda, but not with matter. In our analysis we make use of the current value of the linear bias parameter, b^2(0)= P_{GG}/P_{MM}, where P_{MM} ~ (\\delta\\rho/\\rho)^2 is the present matter power spectrum and P_{GG} is the galaxy fluctuation power spectrum. The former can be computed within a given model, and the latter is found from the observed LSS data (at small z) obtained by the 2dF galaxy redshift survey. It is found that b^2(0)=1 within a 10% accuracy for the standard LCDM model. Adopting this limit for any DE model and using a method based on the effective equation of state for the DE, we can set a limit on the growth of matter density perturbations for the running LCDM model, the solution of which is known. This provides a good test of the procedure, which we then apply to the LXCDM model in order to determine the physical region of parameter space, compatible with the LSS data. In this region, the LXCDM model is consistent with known observations and provides at the same time a viable solution to the cosmic coincidence problem.

Javier Grande; Reuven Opher; Ana Pelinson; Joan Sola

2009-04-27T23:59:59.000Z

139

THE COMPACT STEEP SPECTRUM AND GHZ PEAKED SPECTRUM RADIO SOURCES  

E-Print Network (OSTI)

THE COMPACT STEEP SPECTRUM AND GHZ PEAKED SPECTRUM RADIO SOURCES Christopher P. O'Dea Space@stsci.edu ABSTRACT I review the radio to X­ray properties of GHz Peaked Spectrum (GPS) and Compact Steep Spectrum The GHz Peaked Spectrum (GPS) and Compact Steep Spectrum (CSS) radio sources make up significant fractions

140

SPECTRUM OPPORTUNITY AND INTERFERENCE CONSTRAINT IN OPPORTUNISTIC SPECTRUM ACCESS  

E-Print Network (OSTI)

of the radio spec- trum? Actual spectrum usage measurements obtained by the FCC's Spectrum Policy Task Force [1SPECTRUM OPPORTUNITY AND INTERFERENCE CONSTRAINT IN OPPORTUNISTIC SPECTRUM ACCESS Qing Zhao@ece.ucdavis.edu ABSTRACT In this paper, we study two important concepts in opportunis- tic spectrum access: spectrum

Islam, M. Saif

Note: This page contains sample records for the topic "matter power spectrum" 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

Quark Matter  

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

Quark Quark Matter in Neutron Stars Prashanth Jaikumar Argonne National Laboratory, (PHY) September 7th, 2006 . - p.1/29 Outline * Neutron stars: observations by a theorist . - p.2/29 Outline * Neutron stars: observations by a theorist * Mass-Radius constraints on Equation of State (EoS) . - p.2/29 Outline * Neutron stars: observations by a theorist * Mass-Radius constraints on Equation of State (EoS) * Is quark matter inside neutron stars ruled out? . - p.2/29 Outline * Neutron stars: observations by a theorist * Mass-Radius constraints on Equation of State (EoS) * Is quark matter inside neutron stars ruled out? ------------------------ * Strange Quark stars: Features and "Findings" . - p.2/29 Outline * Neutron stars: observations by a theorist * Mass-Radius constraints on Equation of State (EoS) * Is quark matter inside neutron stars ruled out? ------------------------

142

Intelligent Spectrum Sensor Radio.  

E-Print Network (OSTI)

??A cognitive radio is a radio with built-in intelligence that makes it able to utilize the radio frequency spectrum more efficiently by adapting to the… (more)

Mian, Omer

2008-01-01T23:59:59.000Z

143

E-Print Network 3.0 - asymmetric nuclear matter Sample Search...  

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

nuclear matter Search Powered by Explorit Topic List Advanced Search Sample search results for: asymmetric nuclear matter Page: << < 1 2 3 4 5 > >> 1 Los Alamos National Laboratory...

144

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...

145

Radiation detector spectrum simulator  

DOE Patents (OSTI)

A small battery operated nuclear spectrum simulator having a noise source nerates pulses with a Gaussian distribution of amplitudes. A switched dc bias circuit cooperating therewith generates several nominal amplitudes of such pulses and a spectral distribution of pulses that closely simulates the spectrum produced by a radiation source such as Americium 241.

Wolf, Michael A. (Los Alamos, NM); Crowell, John M. (Los Alamos, NM)

1987-01-01T23:59:59.000Z

146

Radiation detector spectrum simulator  

DOE Patents (OSTI)

A small battery operated nuclear spectrum simulator having a noise source generates pulses with a Gaussian distribution of amplitudes. A switched dc bias circuit cooperating therewith to generate several nominal amplitudes of such pulses and a spectral distribution of pulses that closely simulates the spectrum produced by a radiation source such as Americium 241.

Wolf, M.A.; Crowell, J.M.

1985-04-09T23:59:59.000Z

147

Parametric Adaptive Spectrum Sensing Framework for Dynamic Spectrum Access Networks  

E-Print Network (OSTI)

- ture for dynamic spectrum sensing. In our approach, the radio learns the statistics of the channel Spectrum Sensing Architecture The proposed PASS architecture enables the radio to adapt its spectrumParametric Adaptive Spectrum Sensing Framework for Dynamic Spectrum Access Networks Dinesh Datla

Kansas, University of

148

Mechanism for a bounded and discrete mass spectrum of fermions  

E-Print Network (OSTI)

A mechanism for determining fermion masses in four spacetime dimensions is presented, which uses a scalar-field domain wall extending in a fifth spacelike dimension and a special choice of Yukawa coupling constants. A bounded and discrete fermion mass spectrum is obtained, which depends on a combination of the Yukawa coupling constants and the parameters of the scalar potential. A similar mechanism for a finite mass spectrum may apply to $(1+1)$--dimensional fermions relevant to condensed matter physics.

Klinkhamer, F R

2014-01-01T23:59:59.000Z

149

BNL | ICS Spectrum  

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

Demonstration of Mass-shift and High Harmonics in ICS X-ray Spectrum The recent improvements in the ATF's CO2 laser, in particular, using CO2 isotopes for the picosecond pulse...

150

Technology, safety and costs of decommissioning a reference boiling water reactor power station: Technical support for decommissioning matters related to preparation of the final decommissioning rule  

SciTech Connect

Preparation of the final Decommissioning Rule by the Nuclear Regulatory Commission (NRC) staff has been assisted by Pacific Northwest Laboratory (PNL) staff familiar with decommissioning matters. These efforts have included updating previous cost estimates developed during the series of studies of conceptually decommissioning reference licensed nuclear facilities for inclusion in the Final Generic Environmental Impact Statement (FGEIS) on decommissioning; documenting the cost updates; evaluating the cost and dose impacts of post-TMI-2 backfits on decommissioning; developing a revised scaling formula for estimating decommissioning costs for reactor plants different in size from the reference boiling water reactor (BWR) described in the earlier study; and defining a formula for adjusting current cost estimates to reflect future escalation in labor, materials, and waste disposal costs. This report presents the results of recent PNL studies to provide supporting information in three areas concerning decommissioning of the reference BWR: updating the previous cost estimates to January 1986 dollars; assessing the cost and dose impacts of post-TMI-2 backfits; and developing a scaling formula for plants different in size than the reference plant and an escalation formula for adjusting current cost estimates for future escalation.

Konzek, G.J.; Smith, R.I.

1988-07-01T23:59:59.000Z

151

Technology, safety and costs of decommissioning a reference pressurized water reactor power station: Technical support for decommissioning matters related to preparation of the final decommissioning rule  

SciTech Connect

Preparation of the final Decommissioning Rule by the Nuclear Regulatory Commission (NRC) staff has been assisted by Pacific Northwest Laboratory (PNL) staff familiar with decommissioning matters. These efforts have included updating previous cost estimates developed during the series of studies on conceptually decommissioning reference licensed nuclear facilities for inclusion in the Final Generic Environmental Impact Statement (FGEIS) on decommissioning; documenting the cost updates; evaluating the cost and dose impacts of post-TMI-2 backfits on decommissioning; developing a revised scaling formula for estimating decommissioning costs for reactor plants different in size from the reference pressurized water reactor (PWR) described in the earlier study; defining a formula for adjusting current cost estimates to reflect future escalation in labor, materials, and waste disposal costs; and completing a study of recent PWR steam generator replacements to determine realistic estimates for time, costs and doses associated with steam generator removal during decommissioning. This report presents the results of recent PNL studies to provide supporting information in four areas concerning decommissioning of the reference PWR: updating the previous cost estimates to January 1986 dollars; assessing the cost and dose impacts of post-TMI-2 backfits; assessing the cost and dose impacts of recent steam generator replacements; and developing a scaling formula for plants different in size than the reference plant and an escalation formula for adjusting current cost estimates for future escalation.

Konzek, G.J.; Smith, R.I.

1988-07-01T23:59:59.000Z

152

Frequency spectrum analysis of electromagnetic waves radiated by electrical discharges  

Science Journals Connector (OSTI)

In this study, we analyzed the frequency spectrum of the electromagnetic waves radiated by an electric discharge as a basic method for developing an on-line diagnostic technique for power equipment installed inside closed-switchboards. In order to simulate ... Keywords: closed-switchboard, electromagnetic shielding room, electromagnetic wave, frequency spectrum, local discharge, series arc discharge

Hyeon-Kyu Cha; Sun-Jae Kim; Dae-Won Park; Gyung-Suk Kil

2011-03-01T23:59:59.000Z

153

The Effects of Dark Matter-Baryon Scattering on Redshifted 21 cm Signals  

E-Print Network (OSTI)

We demonstrate that elastic scattering between dark matter (DM) and baryons can affect the thermal evolution of the intergalactic medium at early epochs and discuss the observational consequences. We show that, due to the interaction between DM and baryons, the baryon temperature is cooled after decoupling from the CMB temperature. We illustrate our findings by calculating the 21 cm power spectrum in coexistence with a velocity-dependent DM elastic scattering cross section. For instance, for a DM mass of 10 GeV, the 21 cm brightness temperature angular power spectrum can be suppressed by a factor 2 within the currently allowed DM-baryon cross section bounded by the CMB and large-scale structure data. This scale-independent suppression of the angular power spectrum can be even larger for a smaller DM mass with a common cross section (for instance, as large as a factor 10 for $m_d\\sim 1$ GeV), and such an effect would be of great interest for probing the nature of DM in view of forthcoming cosmological surveys.

Tashiro, Hiroyuki; Silk, Joseph

2014-01-01T23:59:59.000Z

154

The Effects of Dark Matter-Baryon Scattering on Redshifted 21 cm Signals  

E-Print Network (OSTI)

We demonstrate that elastic scattering between dark matter (DM) and baryons can affect the thermal evolution of the intergalactic medium at early epochs and discuss the observational consequences. We show that, due to the interaction between DM and baryons, the baryon temperature is cooled after decoupling from the CMB temperature. We illustrate our findings by calculating the 21 cm power spectrum in coexistence with a velocity-dependent DM elastic scattering cross section. For instance, for a DM mass of 10 GeV, the 21 cm brightness temperature angular power spectrum can be suppressed by a factor 2 within the currently allowed DM-baryon cross section bounded by the CMB and large-scale structure data. This scale-independent suppression of the angular power spectrum can be even larger for a smaller DM mass with a common cross section (for instance, as large as a factor 10 for $m_d\\sim 1$ GeV), and such an effect would be of great interest for probing the nature of DM in view of forthcoming cosmological surveys.

Hiroyuki Tashiro; Kenji Kadota; Joseph Silk

2014-08-11T23:59:59.000Z

155

Utilization and Fairness in Spectrum Assignment for Opportunistic Spectrum Access  

E-Print Network (OSTI)

. INTRODUCTION Wireless devices are becoming ubiquitous, placing increas­ ing stress on the fixed radio spectrum by software defined radio (SDR) technology [5], [15], [23], Open Spectrum allows unlicensed (secondary) users1 Utilization and Fairness in Spectrum Assignment for Opportunistic Spectrum Access Chunyi Peng

Zhao, Ben Y.

156

Utilization and Fairness in Spectrum Assignment for Opportunistic Spectrum Access  

E-Print Network (OSTI)

. INTRODUCTION Wireless devices are becoming ubiquitous, placing increas- ing stress on the fixed radio spectrum by software defined radio (SDR) technology [5], [16], [24], Open Spectrum allows unlicensed (secondary) users1 Utilization and Fairness in Spectrum Assignment for Opportunistic Spectrum Access Chunyi Peng

Almeroth, Kevin C.

157

An Approximate Truthfulness Motivated Spectrum Auction for Dynamic Spectrum Access  

E-Print Network (OSTI)

Radio Spectrum is a critical but scarce resource for wireless communications. Traditionally of spectrum allocation approach, each licensed user has exclusive right for the allocated spectrum, thus facilities as well as the explosive growth of novel wireless services, the demand for radio spectrum

Zhou, Yuanyuan

158

Efficient Dynamic Spectrum Sharing Through Rate Compensation and Spectrum Handoff  

E-Print Network (OSTI)

Abstract--In this work, we propose a heuristic for dynamic spectrum sharing in cognitive radio networks licensed channels available for opportunistic spectrum access. Each SU is equipped with n wEfficient Dynamic Spectrum Sharing Through Rate Compensation and Spectrum Handoff Adisorn

Paris-Sud XI, Université de

159

Radio and Spectrum Management | Department of Energy  

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

Radio and Spectrum Management Radio and Spectrum Management DOE Radio and Spectrum Workshop 43.pdf More Documents & Publications ICAM Workshop Ad Hoc Meetings Spectrum Technology...

160

Broad spectrum solar cell  

DOE Patents (OSTI)

An alloy having a large band gap range is used in a multijunction solar cell to enhance utilization of the solar energy spectrum. In one embodiment, the alloy is In.sub.1-xGa.sub.xN having an energy bandgap range of approximately 0.7 eV to 3.4 eV, providing a good match to the solar energy spectrum. Multiple junctions having different bandgaps are stacked to form a solar cell. Each junction may have different bandgaps (realized by varying the alloy composition), and therefore be responsive to different parts of the spectrum. The junctions are stacked in such a manner that some bands of light pass through upper junctions to lower junctions that are responsive to such bands.

Walukiewicz, Wladyslaw (Kensington, CA); Yu, Kin Man (Lafayette, CA); Wu, Junqiao (Richmond, CA); Schaff, William J. (Ithaca, NY)

2007-05-15T23:59:59.000Z

Note: This page contains sample records for the topic "matter power spectrum" 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

On the Spectrum of Superspheres  

E-Print Network (OSTI)

Sigma models on coset superspaces, such as odd dimensional superspheres, play an important role in physics and in particular the AdS/CFT correspondence. In this work we apply recent general results on the spectrum of coset space models and on supergroup WZNW models to study the conformal sigma model with target space S^{3|2}. We construct its vertex operators and provide explicit formulas for their anomalous dimensions, at least to leading order in the sigma model coupling. The results are used to revisit a non-perturbative duality between the supersphere and the OSP(4|2) Gross-Neveu model that was conjectured by Candu and Saleur. With the help of powerful all-loop results for 1/2 BPS operators in the Gross-Neveu model we are able to recover the entire zero mode spectrum of the sigma model at a certain finite value of the Gross-Neveu coupling. In addition, we argue that the sigma model constraints and equations of motion are implemented correctly in the dual Gross-Neveu description. On the other hand, high(er) gradient operators of the sigma model are not all accounted for. It is possible that this discrepancy is related to an instability from high gradient operators that has previously been observed in the context of Anderson localization.

Alessandra Cagnazzo; Volker Schomerus; Vaclav Tlapak

2014-08-28T23:59:59.000Z

162

On the Spectrum of Superspheres  

E-Print Network (OSTI)

Sigma models on coset superspaces, such as odd dimensional superspheres, play an important role in physics and in particular the AdS/CFT correspondence. In this work we apply recent general results on the spectrum of coset space models and on supergroup WZNW models to study the conformal sigma model with target space S^{3|2}. We construct its vertex operators and provide explicit formulas for their anomalous dimensions, at least to leading order in the sigma model coupling. The results are used to revisit a non-perturbative duality between the supersphere and the OSP(4|2) Gross-Neveu model that was conjectured by Candu and Saleur. With the help of powerful all-loop results for 1/2 BPS operators in the Gross-Neveu model we are able to recover the entire zero mode spectrum of the sigma model at a certain finite value of the Gross-Neveu coupling. In addition, we argue that the sigma model constraints and equations of motion are implemented correctly in the dual Gross-Neveu description. On the other hand, high(er...

Cagnazzo, Alessandra; Tlapak, Vaclav

2014-01-01T23:59:59.000Z

163

NREL Spectrum of Innovation  

SciTech Connect

There are many voices calling for a future of abundant clean energy. The choices are difficult and the challenges daunting. How will we get there? The National Renewable Energy Laboratory integrates the entire spectrum of innovation including fundamental science, market relevant research, systems integration, testing and validation, commercialization and deployment. The innovation process at NREL is interdependent and iterative. Many scientific breakthroughs begin in our own laboratories, but new ideas and technologies come to NREL at any point along the innovation spectrum to be validated and refined for commercial use.

None

2011-01-01T23:59:59.000Z

164

DOE Science Showcase - Neutron Sources for Studying Matter |...  

Office of Scientific and Technical Information (OSTI)

(DOE) Office of Basic Energy Sciences. This activity supports the operation of three neutron scattering facilities, one of the most powerful tools for characterizing matter....

165

I. What is electromagnetic radiation and the electromagnetic spectrum?  

E-Print Network (OSTI)

i­1 I. What is electromagnetic radiation and the electromagnetic spectrum? What do light, X effects on matter. This "stuff" is called electromagnetic radiation, because it travels (radiates) and has electrical and magnetic effects. Electromagnetic radiation is the means for many of our interactions

Sitko, Michael L.

166

The Spectrum of High-Frequency Internal Waves in the Atmospheric Waveguide  

Science Journals Connector (OSTI)

The vertical structure and power spectrum of the field of internal waves generated in the atmospheric waveguide by random vertical displacements were considered in this paper.

I. P. Chunchuzov

1996-07-01T23:59:59.000Z

167

Tensor Detection Severely Constrains Axion Dark Matter  

E-Print Network (OSTI)

The recent detection of B-modes by BICEP2 has non-trivial implications for axion dark matter implied by combining the tensor interpretation with isocurvature constraints from Planck. In this paper the measurement is taken as fact, and its implications considered, though further experimental verification is required. In the simplest inflation models $r=0.2$ implies $H_I=1.1\\times 10^{14}\\text{ GeV}$. If the axion decay constant $f_a1$ accounts for theoretical uncertainty). If $f_a>H_I/2\\pi$ then vacuum fluctuations of the axion field place conflicting demands on axion DM: isocurvature constraints require a DM abundance which is too small to be reached when the back reaction of fluctuations is included. High $f_a$ QCD axions are thus ruled out. Constraints on axion-like particles, as a function of their mass and DM fraction, are also considered. For heavy axions with $m_a\\gtrsim 10^{-22}\\text{ eV}$ we find $\\Omega_a/\\Omega_d\\lesssim 10^{-3}$, with stronger constraints on heavier axions. Lighter axions, however, are allowed and (inflationary) model-independent constraints from the CMB temperature power spectrum and large scale structure are stronger than those implied by tensor modes.

David J. E. Marsh; Daniel Grin; Renee Hlozek; Pedro G. Ferreira

2014-03-17T23:59:59.000Z

168

Chapter 9: Photovoltaic DevicesChapter 9: Photovoltaic Devices Solar energy spectrumSolar energy spectrum  

E-Print Network (OSTI)

Chapter 9: Photovoltaic DevicesChapter 9: Photovoltaic Devices Solar energy spectrumSolar energy Solar Energy? · Clean · Nearly unlimited PHYS5320 Chapter Nine 3 #12;S l ll l t PHYS5320 Chapter Nine 4 Solar cell plant #12;Cars powered by photovoltaic devices PHYS5320 Chapter Nine 5 #12;Solar Energy

Wang, Jianfang

169

Self-interfering matter-wave patterns generated by a moving laser obstacle in a two-dimensional Bose-Einstein condensate inside a power trap cut off by box potential boundaries  

SciTech Connect

We report the observation of highly energetic self-interfering matter-wave (SIMW) patterns generated by a moving obstacle in a two-dimensional Bose-Einstein condensate (BEC) inside a power trap cut off by hard-wall box potential boundaries. The obstacle initially excites circular dispersive waves radiating away from the center of the trap which are reflected from hard-wall box boundaries at the edges of the trap. The resulting interference between outgoing waves from the center of the trap and reflected waves from the box boundaries institutes, to the best of our knowledge, unprecedented SIMW patterns. For this purpose we simulated the time-dependent Gross-Pitaevskii equation using the split-step Crank-Nicolson method and the obstacle was modelled by a moving impenetrable Gaussian potential barrier. Various trapping geometries are considered in which the dynamics of the spatial and momentum density, as well as the energy, are considered. The momentum dynamics reveal an oscillatory behavior for the condensate fraction, indicative of excitations out of and de-excitations back into the condensate state. An oscillatory pattern for the energy dynamics reveals the presence of solitons in the system. Some vortex features are also obtained.

Sakhel, Roger R. [Department of Basic Sciences, Faculty of Information Technology, Isra University, Amman 11622 (Jordan); Sakhel, Asaad R. [Department of Applied Sciences, Faculty of Engineering Technology, Al-Balqa Applied University, Amman 11134 (Jordan); Ghassib, Humam B. [Department of Physics, The University of Jordan, Amman 11942 (Jordan)

2011-09-15T23:59:59.000Z

170

A new approach to searching for dark matter signals in Fermi-LAT gamma rays  

SciTech Connect

Several cosmic ray experiments have measured excesses in electrons and positrons, relative to standard backgrounds, for energies from ? 10 GeV–1 TeV. These excesses could be due to new astrophysical sources, but an explanation in which the electrons and positrons are dark matter annihilation or decay products is also consistent. Fortunately, the Fermi-LAT diffuse gamma ray measurements can further test these models, since the electrons and positrons produce gamma rays in their interactions in the interstellar medium. Although the dark matter gamma ray signal consistent with the local electron and positron measurements should be quite large, as we review, there are substantial uncertainties in the modeling of diffuse backgrounds and, additionally, experimental uncertainties that make it difficult to claim a dark matter discovery. In this paper, we introduce an alternative method for understanding the diffuse gamma ray spectrum in which we take the intensity ratio in each energy bin of two different regions of the sky, thereby canceling common systematic uncertainties. For many spectra, this ratio fits well to a power law with a single break in energy. The two measured exponent indices are a robust discriminant between candidate models, and we demonstrate that dark matter annihilation scenarios can predict index values that require ''extreme'' parameters for background-only explanations.

Chang, Spencer [Physics Department, University of California Davis, One Shields Avenue, Davis, CA 95616 (United States); Goodenough, Lisa, E-mail: spchang@ucdavis.edu, E-mail: lcg261@nyu.edu [Center for Cosmology and Particle Physics, Department of Physics, New York University, 4 Washington Place, New York, NY 10003 (United States)

2010-08-01T23:59:59.000Z

171

Dark Matter vs. Neutrinos: The effect of astrophysical uncertainties and timing information on the neutrino floor  

E-Print Network (OSTI)

Future multi-tonne Direct Detection experiments will be sensitive to solar neutrino induced nuclear recoils which form an irreducible background to light Dark Matter searches. Indeed for masses around 6 GeV the spectra of neutrinos and Dark Matter are so similar that experiments will run into a neutrino floor, for which sensitivity increases only marginally with exposure past a certain cross section. In this work we show that this floor can be overcome using the different annual modulation expected from solar neutrinos and Dark Matter. Specifically for cross sections below the neutrino floor the DM signal is observable through a phase shift and a smaller amplitude for the time-dependent event rate. This allows the exclusion power to be improved by up to an order of magnitude for large exposures. In addition we demonstrate that the neutrino floor exists over a wider mass range than has been previously shown, since the large uncertainties in the Dark Matter velocity distribution make the signal spectrum harder to distinguish from the neutrino background. However for most velocity distributions the neutrino floor can still be surpassed using timing information, though certain velocity streams may prove problematic.

Jonathan H. Davis

2014-12-03T23:59:59.000Z

172

Inflation that runs naturally: Gravitational waves and suppression of power at large and small scales  

E-Print Network (OSTI)

We point out three correlated predictions of the axion monodromy inflation model: large amplitude of gravitational waves, suppression of power on horizon scales and on scales relevant for the formation of dwarf galaxies. While these predictions are likely generic to models with oscillations in the inflaton potential, the axion monodromy model naturally accommodates the required running spectral index through Planck-scale corrections to the inflaton potential. Applying this model to a combined data set of Planck, ACT, SPT, and WMAP low-$\\ell$ polarization cosmic microwave background (CMB) data, we find a best-fit tensor-to-scalar ratio $r_{0.05} = 0.07^{+0.05}_{-0.04}$ due to gravitational waves, which may have been observed by the BICEP2 experiment. Despite the contribution of gravitational waves, the total power on large scales (CMB power spectrum at low multipoles) is lower than the standard $\\Lambda$CDM cosmology with a power-law spectrum of initial perturbations and no gravitational waves, thus mitigating some of the tension on large scales. There is also a reduction in the matter power spectrum of 20-30\\% at scales corresponding to $k = 10~{\\rm Mpc}^{-1}$, which are relevant for dwarf galaxy formation. This will alleviate some of the unsolved small-scale structure problems in the standard $\\Lambda$CDM cosmology.

Quinn E. Minor; Manoj Kaplinghat

2014-11-03T23:59:59.000Z

173

Spectrum Mobility Games Richard Southwell  

E-Print Network (OSTI)

by allowing cognitive radio devices to opportunisti- cally access underutilized licensed spectrum while With the unprecedented growth in the number of mobile devices and wireless services, the radio frequency spectrum are widely underutilized. Cognitive radio technology has the great potential to alleviate spectrum scarcity

Huang, Jianwei

174

Hybrid spread spectrum radio system  

DOE Patents (OSTI)

Systems and methods are described for hybrid spread spectrum radio systems. A method, includes receiving a hybrid spread spectrum signal including: fast frequency hopping demodulating and direct sequence demodulating a direct sequence spread spectrum signal, wherein multiple frequency hops occur within a single data-bit time and each bit is represented by chip transmissions at multiple frequencies.

Smith, Stephen F. (London, TN) [London, TN; Dress, William B. (Camas, WA) [Camas, WA

2010-02-09T23:59:59.000Z

175

Moisture Matters | EMSL  

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

Moisture Matters Moisture Matters Cryogenic microscopy methods yield insights to microbial morphology State-of-the-art cryogenic electron microscopy (EM) approaches at EMSL are...

176

Dark Matter Theory  

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

Dark Matter Theory Dark Matter Theory Understanding discoveries at the Energy, Intensity, and Cosmic Frontiers Get Expertise Rajan Gupta (505) 667-7664 Email Bruce Carlsten (505)...

177

Discrete multiwavelength spectrum created  

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

Supramolecular structure of polymer blends Supramolecular structure of polymer blends * Macroscale self-similarity of rocks * Structure of colloidal crystals and alloys * Hydration of cement pastes * Aggregation in colloidal dispersions * Self-assembling of polymers * Mesoscopic structure of natural composites * Structure of granular powders * Morphology of colloidal reinforcing fillers * Structure and morphology of complex fluids * Rheology and morphology of hydrogels 06-G01637F/gim Moderator Decoupled poisoned hydrogen Source- detector distance 30 m Focusing premono- chromator Cooper mosaic Cu(111) crystals Monochro- mator and analyzer Si(220) channel-cut, triple-bounce crystals Bragg angle 70° Wavelength spectrum 4 Bragg

178

Current Dark Matter Annihilation Constraints from CMB and Low-Redshift Data  

E-Print Network (OSTI)

Updated constraints on dark matter cross section and mass are presented combining CMB power spectrum measurements from Planck, WMAP9, ACT, and SPT as well as several low-redshift datasets (BAO, HST, supernovae). For the CMB datasets, we combine WMAP9 temperature and polarization data for l 2500, and Planck CMB four-point lensing measurements. We allow for redshift-dependent energy deposition from dark matter annihilation by using a `universal' energy absorption curve. We also include an updated treatment of the excitation, heating, and ionization energy fractions, and provide updated deposition efficiency factors (f_eff) for 41 different dark matter models. Assuming perfect energy deposition (f_eff = 1) and a thermal cross section, dark matter masses below 26 GeV are excluded at the 2-sigma level. Assuming a more generic efficiency of f_eff = 0.2, thermal dark matter masses below 5 GeV are disfavored at the 2-sigma level. These limits are a factor of ~2 improvement over those from WMAP9 data alone. These current constraints probe, but do not exclude, dark matter as an explanation for reported anomalous indirect detection observations from AMS-02/PAMELA and the Fermi Gamma-ray Inner Galaxy data. They also probe relevant models that would explain anomalous direct detection events from CDMS, CRESST, CoGeNT, and DAMA, as originating from a generic thermal WIMP. Projected constraints from the full Planck release should improve the current limits by another factor of ~2, but will not definitely probe these signals. The proposed CMB Stage IV experiment will more decisively explore the relevant regions and improve upon the Planck constraints by another factor of ~2.

Mathew S. Madhavacheril; Neelima Sehgal; Tracy R. Slatyer

2014-11-28T23:59:59.000Z

179

Inert scalar dark matter in an extra dimension inspired model  

E-Print Network (OSTI)

In this paper we analyze a dark matter model inspired by theories with extra dimensions. The dark matter candidate corresponds to the first Kaluza-Klein mode of a real scalar added to the Standard Model. The tower of new particles enriches the calculation of the relic abundance. For large mass splitting, the model converges to the predictions of the inert singlet dark matter model. For nearly degenerate mass spectrum, coannihilations increase the cross-sections used for direct and indirect dark matter searches. Moreover, the Kaluza-Klein zero mode can mix with the SM higgs and further constraints can be applied.

R. A. Lineros; F. A. Pereira dos Santos

2014-11-12T23:59:59.000Z

180

Discharge convective instability as modifier of nonlinear hydrodynamic spectrum  

E-Print Network (OSTI)

Discharge source is considered as modifier of flow hydrodynamic spectrum. Characteristic frequency of nonlinear spectrum and spectrum power were determined under conditions of arc sliding discharge in supersonic flow. Two stages of discharge were defined: sliding stage and still stage. It was found that stage transition occurs due to convective instability of discharge. Fraction of sliding stage in overall discharge duration is determined by averaged current that is general stable discharge parameter. This phenomenon gives opportunity to control power of pressure fluctuations spectrum. Theoretical insight of field and hydrodynamic factors influencing on pulsations frequency was achieved. Hydrodynamic resistance of discharge region and holding cathode electric field turned out to be basic factors of frequency modification. Corresponding experimental verification was taken. Basic frequency law was determined for several discharge regimes.

Sergey Kamenshchikov

2012-04-26T23:59:59.000Z

Note: This page contains sample records for the topic "matter power spectrum" 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

Spectrum sharing in cognitive radio networks.  

E-Print Network (OSTI)

??Years of growth in wireless communication services and conservative spectrum allocation policies by government regulators have led to spectrum scarcity. On the other hand, spectrum… (more)

Ahmed, Waqas

2012-01-01T23:59:59.000Z

182

Spectrum Policy Seminar | Department of Energy  

Energy Savers (EERE)

Policy Seminar Spectrum Policy Seminar Slide show from FCC's Public Safety and Homeland Security Bureau's presenation on spectrum policy. Spectrum Policy Seminar More Documents &...

183

Terahertz bandwidth integrated radio frequency spectrum analyzer via nonlinear optics  

E-Print Network (OSTI)

We report an integrated all-optical radio frequency spectrum analyzer based on a ~ 4cm long doped silica glass waveguide, with a bandwidth greater than 2.5 THz. We use this device to characterize the intensity power spectrum of ultrahigh repetition rate mode-locked lasers at repetition rates up to 400 GHz, and observe dynamic noise related behavior not observable with other techniques.

Ferrera, Marcello; Pasquazi, Alessia; Peccianti, Marco; Clerici, Matteo; Caspani, Lucia; Chu, Sai T; Little, Brent E; Morandotti, Roberto; Moss, David J

2014-01-01T23:59:59.000Z

184

Recent Developments in Supersymmetric and Hidden Sector Dark Matter  

SciTech Connect

New results which correlate SUSY dark matter with LHC signals are presented, and a brief review of recent developments in supersymmetric and hidden sector dark matter is given. It is shown that the direct detection of dark matter is very sensitive to the hierarchical SUSY sparticle spectrum and the spectrum is very useful in distinguishing models. It is shown that the prospects of the discovery of neutralino dark matter are very bright on the 'Chargino Wall' due to a copious number of model points on the Wall, where the NLSP is the Chargino, and the spin independent neutralino-proton cross section is maintained at high values in the 10{sup -44} cm{sup 2} range for neutralino masses up to {approx}850 GeV. It is also shown that the direct detection of dark matter along with lepton plus jet signatures and missing energy provide dual, and often complementary, probes of supersymmetry. Finally, we discuss an out of the box possibility for dark matter, which includes dark matter from the hidden sector, which could either consist of extra weakly interacting dark matter (a Stino XWIMP), or milli-charged dark matter arising from the Stueckelberg extensions of the MSSM or the SM.

Feldman, Daniel; Liu Zuowei [Department of Physics, Northeastern University, Boston, MA 02115 (United States); Nath, Pran [Department of Physics, Northeastern University, Boston, MA 02115 (United States); TH Division, PH Department, CERN, CH-1211 Geneva 23 (Switzerland)

2008-11-23T23:59:59.000Z

185

Recent Developments in Supersymmetric and Hidden Sector Dark Matter  

E-Print Network (OSTI)

New results which correlate SUSY dark matter with LHC signals are presented, and a brief review of recent developments in supersymmetric and hidden sector dark matter is given. It is shown that the direct detection of dark matter is very sensitive to the hierarchical SUSY sparticle spectrum and the spectrum is very useful in distinguishing models. It is shown that the prospects of the discovery of neutralino dark matter are very bright on the "Chargino Wall" due to a copious number of model points on the Wall, where the NLSP is the Chargino, and the spin independent neutralino-proton cross section is maintained at high values in the $10^{-44}$cm$^{2}$ range for neutralino masses up to $\\sim 850$ GeV . It is also shown that the direct detection of dark matter along with lepton plus jet signatures and missing energy provide dual, and often complementary, probes of supersymmetry. Finally, we discuss an out of the box possibility for dark matter, which includes dark matter from the hidden sector, which could either consist of extra weakly interacting dark matter (a Stino XWIMP), or milli-charged dark matter arising from the Stueckelberg extensions of the MSSM or the SM.

Daniel Feldman; Zuowei Liu; Pran Nath

2008-06-29T23:59:59.000Z

186

NREL: Innovation Spectrum - NREL Spectrum of Innovation Video...  

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

are many...and the challenges are daunting. How will we get there? The National Renewable Energy Laboratory integrates the entire spectrum of innovation, including Fundamental...

187

Accurate universal models for the mass accretion histories and concentrations of dark matter halos  

E-Print Network (OSTI)

A large amount of observations have constrained cosmological parameters and the initial density fluctuation spectrum to a very high accuracy. However, cosmological parameters change with time and the power index of the power spectrum varies with mass scale dramatically in the so-called concordance Lambda CDM cosmology. Thus, any successful model for its structural evolution should work well simultaneously for various cosmological models and different power spectra. We use a large set of high-resolution N-body simulations of a variety of structure formation models (scale-free, standard CDM, open CDM, and Lambda CDM) to study the mass accretion histories (MAHs), the mass and redshift dependence of concentrations and the concentration evolution histories of dark matter halos. We find that there is significant disagreement between the much-used empirical models in the literature and our simulations. According to two simple but tight correlations we find from the simulation results, we develop new empirical models for both the MAHs and the concentration evolution histories of dark matter halos, and the latter can also be used to predict the mass and redshift dependence of halo concentrations. These models are accurate and universal: the same set of model parameters works well for different cosmological models and for halos of different masses at different redshifts and the model predictions are highly accurate even when the histories are traced to very high redshift. These models are also simple and easy to implement. A web calculator and a user-friendly code to make the relevant calculations are available from http://www.shao.ac.cn/dhzhao/mandc.html . We explain why Lambda CDM halos on nearly all mass scales show two distinct phases in their evolution histories.

D. H. Zhao; Y. P. Jing; H. J. Mo; G. Boerner

2009-11-30T23:59:59.000Z

188

Federal Spectrum Management at the National Telecommunications...  

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

Federal Spectrum Management at the National Telecommunications and Information Administration Federal Spectrum Management at the National Telecommunications and Information...

189

Mesoscopic Fractional Quantum in Soft Matter  

E-Print Network (OSTI)

Soft matter (e.g., biomaterials, polymers, sediments, oil, emulsions) has become an important bridge between physics and diverse disciplines. Its fundamental physical mechanism, however, is largely obscure. This study made the first attempt to connect fractional Schrodinger equation and soft matter physics under a consistent framework from empirical power scaling to phenomenological kinetics and macromechanics to mesoscopic quantum mechanics. The original contributions are the fractional quantum relationships, which show Levy statistics and fractional Brownian motion are essentially related to momentum and energy, respectively. The fractional quantum underlies fractal mesostructures and many-body interactions of macromolecules in soft matter and is experimentally testable.

W Chen

2005-05-09T23:59:59.000Z

190

Spectrum Sensing and Reconstruction for Cognitive Radio  

E-Print Network (OSTI)

Spectrum Sensing and Reconstruction for Cognitive Radio Amanpreet S Saini, Zhen Hu, Robert Qiu with spectrum sensing and spectrum reconstruction under the umbrella of cognitive radio which is the smart radio to explore and exploit the free spectrum. Spectrum analyzer is used to emulate cognitive radio to do spectrum

Qiu, Robert Caiming

191

Calculation of the Ostriker-Vishniac Effect in Cold Dark Matter Models  

E-Print Network (OSTI)

We present a new derivation of the cosmic microwave background anisotropy spectrum from the Ostriker-Vishniac effect for an open, flat, or closed Universe, and calculate the anisotropy expected in cold dark-matter (CDM) models. We provide simple semi-analytic fitting formulas for the Vishniac power spectrum that can be used to evaluate the expected anisotropy in CDM models for any arbitrary ionization history. In a flat Universe, CDM models normalized to cluster abundances produce rms temperature anisotropies of 0.8--2.4 $\\mu$K on arcminute angular scales for a constant ionization fraction of unity, whereas an ionization fraction of 0.2 yields rms anisotropies of 0.3--0.8 $\\mu$K. In an open and/or high-baryon-density Universe, the level of anisotropy is somewhat higher. The signal in some of these models may be detectable with planned interferometry experiments. The damping of the acoustic peaks in the primary-anisotropy spectrum at degree angular scales depends primarily on the optical depth and only secondarily on the epoch of reionization. On the other hand, the amplitude of Ostriker-Vishniac anisotropies depends sensitively on the epoch of reionization. Therefore, when combined with the estimate of the reionization optical depth provided by maps of degree-scale anisotropies, the Ostriker-Vishniac effect can provide a unique probe of the epoch of reionization.

A. H. Jaffe; M. Kamionkowski

1998-06-18T23:59:59.000Z

192

RHIC | Why Does Quark Matter Matter?  

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

Why Does Quark Matter 'Matter'? Why Does Quark Matter 'Matter'? The history of modern technological development can be viewed as a series of investigations, with ever increasing resolution, into the microscopic structure of matter. Since the days of the early Greek philosophers, science has been on a continual quest to find the smallest piece - the most fundamental building block - forming the substance of the universe. STAR researchers During that journey, many beautiful and exotic properties of the subatomic world have been discovered: particles with wave-like properties the ultimate position of which can never be known; "particles" of light that deliver a fixed amount of energy when they strike the atoms of a material's surface; particles in some types of electrical conductors that

193

E-Print Network 3.0 - appearing 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: appearing white matter Page: << < 1 2 3 4 5 > >> 1 IEEE Trans. Medical Imaging, to...

194

NREL: Innovation Spectrum Home Page  

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

Innovation Spectrum Innovation Spectrum Te xt version The scope of NREL's capabilities emulates the nature of the innovation process itself. Moving new technologies from initial concept to commercial application requires a breadth of expertise across the innovation spectrum, encompassing: Fundamental science Market-relevant research Systems integration Testing and validation Commercialization Deployment The NREL innovation spectrum is highly interactive within the laboratory and across other research institutions and private industry. NREL provides the scientific and analytical leadership to guide the innovation process, contributing knowledge and expertise at each stage. Innovation Success Stories Learn more about the spectrum of clean energy innovation and how NREL is creating a future of sustainable energy systems based on clean,

195

Just the Basics: Particulate Matter  

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

is Particulate is Particulate Matter? One of the major components of air pollution is particulate matter, or PM. PM refers to airborne particles that include dust, dirt, soot, smoke, and liquid droplets. These particles can range in size from microscopic to large enough to be seen. PM is characterized by its size, with fine particles of less than 2.5 micrometers in size designated as PM 2.5 and coarser particles between 2.5 and 10 micrometers in size designated as PM 10 . PM arises from many sources, including combustion occurring in factories, power plants, cars, trucks, buses, trains, or wood fires; or through simple agitation of existing particulates by tilling of land, quarrying and stone-crushing, and off- road vehicular movement. Of particular interest is PM generated during diesel

196

in Condensed Matter Physics  

E-Print Network (OSTI)

Master in Condensed Matter Physics ­ Master académique #12;2 #12;3 Students at the University. Condensed matter physics is about explaining and predicting the relationship between the atomic, and broad education in the field of condensed matter physics · introduce you to current research topics

van der Torre, Leon

197

Low frequency radio spectrum and spectral turnover of LS 5039  

E-Print Network (OSTI)

LS 5039, a possible black hole x-ray binary, was recently observed with Giant Meterwave Radio Telescope. The observed spectrum presented here shows that the spectrum is inverted at the low frequency. When combined with the archival data with orbital phase similar to the present observations, it shows a clear indication of a spectral turnover. The combined data are fitted with a broken power-law and the break frequency signifies a possible spectral turnover of the spectrum around 964 MHz. Truly simultaneous observations in radio wavelength covering a wide range of frequencies are required to fix the spectrum and the spectral turn over which will play a crucial role in developing a deeper understanding of the radio emitting jet in LS 5039.

Sagar Godambe; Subir Bhattacharyya; Nilay Bhatt; Manojendu Choudhury

2008-07-15T23:59:59.000Z

198

COBE Data Spatial--Frequency Analysis and CMB Anisotropy Spectrum  

E-Print Network (OSTI)

We discuss the problem of CMB spectrum corruption during Galactic emission removing. A new technique of spatial--frequency data reduction is proposed. The technique gives us a possibility to avoid a spatial harmonics nonorthogonality. The proposed technique is applied to the two-year COBE DMR sky maps. We exclude the harmonics with l=7, 9,13, 23 and 25 as having anomalous statistics noise behavior. One shows that procedure do not give systematic errors, if the data are statistically regular. The spectral parameter of the power spectrum of primordial perturbation $n=1.84 \\pm 0.29$ and quadrupole moment $Q_2=15.22 \\pm 3.0$ are estimated. The power spectrum estimation results are inconsistent with the Harrison-Zel`dovich $n=1$ model with the confidence 99%. It is shown a necessity of an increasing a survey sensitivity to reach a more reliable estimation of the cosmological signal.

A. A. Brukhanov; D. P. Skulachev; I. A. Strukov; T. V. Konkina

1995-12-22T23:59:59.000Z

199

The Optical Spectrum of the Vela Pulsar  

E-Print Network (OSTI)

Our knowledge of the optical spectra of Isolated Neutron Stars (INSs) is limited by their intrinsic faintness. Among the fourteen optically identified INSs, medium resolution spectra have been obtained only for a handful of objects. No spectrum has been published yet for the Vela pulsar (PSR B0833-45), the third brightest (V=23.6) INS with an optical counterpart. Optical multi-band photometry underlines a flat continuum.In this work we present the first optical spectroscopy observations of the Vela pulsar, performed in the 4000-11000 A spectral range.Our observations have been performed at the ESO VLT using the FORS2 instrument. The spectrum of the Vela pulsar is characterized by a flat power-law (alpha = -0.04 +/- 0.04), which compares well with the values obtained from broad-band photometry. This confirms, once more, that the optical emission of Vela is entirely of magnetospheric origin. The comparison between the optical spectral indeces of rotation-powered INSs does not show evidence for a spectral evolution suggesting that, as in the X-rays, the INS aging does not affect the spectral properties of the magnetospheric emission. At the same time, the optical spectral indeces are found to be nearly always flatter then the X-rays ones, clearly suggesting a general spectral turnover at lower energies.

R. P. Mignani; S. Zharikov; P. A. Caraveo

2007-07-13T23:59:59.000Z

200

ACCURATE UNIVERSAL MODELS FOR THE MASS ACCRETION HISTORIES AND CONCENTRATIONS OF DARK MATTER HALOS  

SciTech Connect

A large amount of observations have constrained cosmological parameters and the initial density fluctuation spectrum to a very high accuracy. However, cosmological parameters change with time and the power index of the power spectrum dramatically varies with mass scale in the so-called concordance LAMBDACDM cosmology. Thus, any successful model for its structural evolution should work well simultaneously for various cosmological models and different power spectra. We use a large set of high-resolution N-body simulations of a variety of structure formation models (scale-free, standard CDM, open CDM, and LAMBDACDM) to study the mass accretion histories, the mass and redshift dependence of concentrations, and the concentration evolution histories of dark matter halos. We find that there is significant disagreement between the much-used empirical models in the literature and our simulations. Based on our simulation results, we find that the mass accretion rate of a halo is tightly correlated with a simple function of its mass, the redshift, parameters of the cosmology, and of the initial density fluctuation spectrum, which correctly disentangles the effects of all these factors and halo environments. We also find that the concentration of a halo is strongly correlated with the universe age when its progenitor on the mass accretion history first reaches 4% of its current mass. According to these correlations, we develop new empirical models for both the mass accretion histories and the concentration evolution histories of dark matter halos, and the latter can also be used to predict the mass and redshift dependence of halo concentrations. These models are accurate and universal: the same set of model parameters works well for different cosmological models and for halos of different masses at different redshifts, and in the LAMBDACDM case the model predictions match the simulation results very well even though halo mass is traced to about 0.0005 times the final mass, when cosmological parameters and the power index of the initial density fluctuation spectrum have changed dramatically. Our model predictions also match the PINOCCHIO mass accretion histories very well, which are much independent of our numerical simulations and our definitions of halo merger trees. These models are also simple and easy to implement, making them very useful in modeling the growth and structure of dark matter halos. We provide appendices describing the step-by-step implementation of our models. A calculator which allows one to interactively generate data for any given cosmological model is provided on the Web, together with a user-friendly code to make the relevant calculations and some tables listing the expected concentration as a function of halo mass and redshift in several popular cosmological models. We explain why LAMBDACDM and open CDM halos on nearly all mass scales show two distinct phases in their mass growth histories. We discuss implications of the universal relations we find in connection to the formation of dark matter halos in the cosmic density field.

Zhao, D. H.; Jing, Y. P. [Key Laboratory for Research in Galaxies and Cosmology, Shanghai Astronomical Observatory, CAS, 80 Nandan Road, Shanghai 200030 (China); Mo, H. J. [Department of Astronomy, University of Massachusetts, Amherst, MA 01003 (United States); Boerner, G., E-mail: dhzhao@shao.ac.c [Max-Planck-Institut fuer Astrophysik, Karl-Schwarzschild-Strasse 1, 85748 Garching (Germany)

2009-12-10T23:59:59.000Z

Note: This page contains sample records for the topic "matter power spectrum" 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

HESS Observations of the Galactic Center Region and Their Possible Dark Matter Interpretation  

Science Journals Connector (OSTI)

The detection of ? rays from the source HESS J1745-290 in the Galactic Center (GC) region with the High Energy Spectroscopic System (HESS) array of Cherenkov telescopes in 2004 is presented. After subtraction of the diffuse ?-ray emission from the GC ridge, the source is compatible with a point source with spatial extent less than 1.2?(stat) (95% C.L.). The measured energy spectrum above 160 GeV is compatible with a power law with photon index of 2.25±0.04(stat)±0.10(syst) and no significant flux variation is detected. It is finally found that the bulk of the very high energy emission must have non-dark-matter origin.

F. Aharonian et al. (HESS Collaboration)

2006-11-30T23:59:59.000Z

202

NREL: Innovation Spectrum - NREL Spectrum of Innovation Video (Text  

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

Spectrum of Innovation Video (Text Version) Spectrum of Innovation Video (Text Version) Below is the text version of the NREL Spectrum of Innovation video. "...renewable energy is a national imperative..." "...This breakthrough technology will..." "...we are still looking for an innovative material that will..." "...we need a study to determine..." "...the right people need to work together..." "...competing priorities mean we cannot..." There are many voices calling for a future of abundant, clean energy. The choices are many...and the challenges are daunting. How will we get there? The National Renewable Energy Laboratory integrates the entire spectrum of innovation, including Fundamental Science, Market-Relevant Research, Systems Integration, Testing and Validation, Commercialization, and

203

Big Questions: Dark Matter  

ScienceCinema (OSTI)

Carl Sagan's oft-quoted statement that there are "billions and billions" of stars in the cosmos gives an idea of just how much "stuff" is in the universe. However scientists now think that in addition to the type of matter with which we are familiar, there is another kind of matter out there. This new kind of matter is called "dark matter" and there seems to be five times as much as ordinary matter. Dark matter interacts only with gravity, thus light simply zips right by it. Scientists are searching through their data, trying to prove that the dark matter idea is real. Fermilab's Dr. Don Lincoln tells us why we think this seemingly-crazy idea might not be so crazy after all.

Lincoln, Don

2014-08-07T23:59:59.000Z

204

Power Plant Power Plant  

E-Print Network (OSTI)

Basin Center for Geothermal Energy at University of Nevada, Reno (UNR) 2 Nevada Geodetic LaboratoryStillwater Power Plant Wabuska Power Plant Casa Diablo Power Plant Glass Mountain Geothermal Area Lassen Geothermal Area Coso Hot Springs Power Plants Lake City Geothermal Area Thermo Geothermal Area

Tingley, Joseph V.

205

Visible Spectrum Incandescent Selective Emitter  

SciTech Connect

The purpose of the work performed was to demonstrate the feasibility of a novel bi-layer selective emitter. Selective emitters are incandescent radiant bodies with emissivities that are substantially larger in a selected part of the radiation spectrum, thereby significantly shifting their radiated spectral distribution from that of a blackbody radiating at the same temperature. The major research objectives involved answering the following questions: (1) What maximum VIS/NIR radiant power and emissivity ratios can be attained at 2650 K? (2) What is the observed emitter body life and how does its performance vary with time? (3) What are the design tradeoffs for a dual heating approach in which both an internally mounted heating coil and electrical resistance self-heating are used? (4) What are the quantitative improvements to be had from utilizing a bi-layer emitter body with a low emissivity inner layer and a partially transmissive outer layer? Two approaches to obtaining selective emissivity were investigated. The first was to utilize large optical scattering within an emitter material with a spectral optical absorption that is much greater within the visible spectrum than that within the NIR. With this approach, an optically thick emitter can radiate almost as if optically thin because essentially, scattering limits the distance below the surface from which significant amounts of internally generated radiation can emerge. The performance of thin emitters was also investigated (for optically thin emitters, spectral emissivity is proportional to spectral absorptivity). These emitters were fabricated from thin mono-layer emitter rods as well as from bi-layer rods with a thin emitter layer mounted on a substrate core. With an initially estimated energy efficiency of almost three times that of standard incandescent bulbs, a number of energy, economic and environmental benefits such as less energy use and cost, reduced CO{sub 2} emissions, and no mercury contamination was initially projected. The work performed provided answers to a number of important questions. The first is that, with the investigated approaches, the maximum sustained emitter efficiencies are about 1.5 times that of a standard incandescent bulb. This was seen to be the case for both thick and thin emitters, and for both mono-layer and bi-layer designs. While observed VIS/NIR ratios represent improvements over standard incandescent bulbs, it does not appear sufficient to overcome higher cost (i.e. up to five times that of the standard bulb) and ensure commercial success. Another result is that high temperatures (i.e. 2650 K) are routinely attainable without platinum electrodes. This is significant for reducing material costs. A novel dual heating arrangement and insulated electrodes were used to attain these temperatures. Another observed characteristic of the emitter was significant grain growth soon after attaining operating temperatures. This is an undesirable characteristic that results in substantially less optical scattering and spectral selectivity, and which significantly limits emitter efficiencies to the values reported. Further work is required to address this problem.

Sonsight Inc.

2004-04-30T23:59:59.000Z

206

Power Factor Reactive Power  

E-Print Network (OSTI)

power: 130 watts Induction motor PSERC Incandescent lights 0 0.002 0.004 0.006 0.008 0.01 0.012 0.014 0 power: 150 watts #12;Page 4 PSERC Incandescent Lights PSERC Induction motor with no load #12;Page 5 Incandescent Lights #12;Page 7 PSERC Incandescent lights power: Power = 118 V x 1.3 A = 153 W = 0.15 kW = power

207

Raman Spectrum of Heavy Water  

Science Journals Connector (OSTI)

... . of 99.2 gm./lOO gm. D2O ( 1.1049) supplied by the Norsk Hydro-Elektrisk Kvaelstofaktieselskab. The Raman spectrum of the substance was photographed with a Hilger ...

R. ANANTHAKRISHNAN

1935-10-05T23:59:59.000Z

208

Spectrum of C_heart  

E-Print Network (OSTI)

Spectrum of C_heart where 1 + z + 2\\sqrt{1 - z^2} heart(z)= ------------------------- 3 - z + 2\\sqrt{1 - z^2}. Figure 7.1, page 303, of "Composition Operators on Spaces ...

209

The Universe Adventure - The Search for Dark Matter  

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

Search for Dark Matter Search for Dark Matter Large Hadron Collider Particle accelerators, such as the newly constructed LHC (Large Hadron Collider) at CERN in Geneva, Switzerland, use powerful magnets to accelerate particles to velocities near that of light and collide them into target beams. Physicists analyze the spray of particles created by the collisions which may contain clues about the properties of elusive dark matter particles. Today the search for dark matter is carried out in labs, observatories, and particle accelerators around the world. Scientists hope that the next generation of experiments will finally uncover the identity of dark matter. Alternatives to Dark Matter Some cosmologists are looking for alternative theories that explain these phenomena without relying on unobservable dark matter. Most of these

210

Laser-Matter Interaction Below the Plasma Ignition Threshold Intensity  

Science Journals Connector (OSTI)

In this chapter we present the process of laser-matter interaction below the plasma ignition threshold intensity. When the high power laser radiation characterized by electric field intensities around ...

Mihai Stafe; Aurelian Marcu; Niculae N. Puscas

2014-01-01T23:59:59.000Z

211

Hardening neutron spectrum for advanced actinide transmutation experiments in the ATR  

Science Journals Connector (OSTI)

......constant neutron-flux field, the fission power is...over the neutron energy range 0...the neutron spectrum such that all the thermal neutrons...Nuclear Energy-Engineering...fraction of neutron induced gamma-heat...Hardening neutron spectrum for advanced...shorter-lived fission products...performed in a thermal test reactor......

G. S. Chang; R. G. Ambrosek

2005-12-20T23:59:59.000Z

212

Spectrum Clouds: A Session Based Spectrum Trading System for Multi-hop Cognitive Radio Networks  

E-Print Network (OSTI)

of opportunistic using licensed spectrum bands has initiated the spectrum trading in multi-hop cognitive radioSpectrum Clouds: A Session Based Spectrum Trading System for Multi-hop Cognitive Radio Networks in the demand for radio spectrum. In parallel with that, current static spectrum allocation policy of Federal

Latchman, Haniph A.

213

Spectrum Technology Workshop | Department of Energy  

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

Technology Workshop Spectrum Technology Workshop Agenda.pdf More Documents & Publications Radio and Spectrum Management Transuranic Waste Transportation Working Group Agenda...

214

Spectrum sensing through implementation of USRP2.  

E-Print Network (OSTI)

??Scarcity of the wireless spectrum has led to the development of new techniques for better utilization of the wireless spectrum. Demand for high data rates… (more)

Aftab, Adnan

2011-01-01T23:59:59.000Z

215

Compressive Spectrum Sensing for Cognitive Radio Networks.  

E-Print Network (OSTI)

??Spectrum sensing is the most important part in cognitive radios. Wideband spectrum sensing requires high speed and large data samples. It makes sampling process challenging… (more)

Nakarmi, Ukash

2011-01-01T23:59:59.000Z

216

WTB & Spectrum Access Overview | Department of Energy  

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

WTB & Spectrum Access Overview More Documents & Publications An Introduction to Spectrum Engineering NBP RFI: Communications Requirements Reply Comments of Southern Company...

217

The Matter of Detailing  

Science Journals Connector (OSTI)

Project success is truly a “matter of detailing”! So, it is imperative that the strongest of cases must be made for the process of detailing!

Ralph W. Liebing RA; CSI; CPCA; CBO

2011-01-01T23:59:59.000Z

218

EMSL - soil organic matter  

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

soil-organic-matter en Structures and Stabilities of (MgO)n Nanoclusters. http:www.emsl.pnl.govemslwebpublicationsstructures-and-stabilities-mgon-nanoclusters

219

Dark matter at colliders  

SciTech Connect

We show that colliders can impose strong constraints on dark matter. We take an effective field theory approach where dark matter couples to quarks and gluons through high dimensional operators. We discuss limits on interactions of dark matter and hadronic matter from the ATLAS experiment at the Large Hadron Collider (LHC). For spin-independent scattering, the LHC limits are stronger than those from direct detection experiments for light WIMPs. For spin-dependent scattering, the LHC sets better limits over much of parameter space.

Yu Haibo [Department of Physics, University of Michigan, Ann Arbor, MI, 48109 (United States)

2013-05-23T23:59:59.000Z

220

Parameter constraints for flat cosmologies from CMB and 2dFGRS power spectra  

E-Print Network (OSTI)

We constrain flat cosmological models with a joint likelihood analysis of a new compilation of data from the cosmic microwave background (CMB) and from the 2dF Galaxy Redshift Survey (2dFGRS). Fitting the CMB alone yields a known degeneracy between the Hubble constant h and the matter density Omega_m, which arises mainly from preserving the location of the peaks in the angular power spectrum. This `horizon-angle degeneracy' is considered in some detail and shown to follow a simple relation Omega_m h^{3.4} = constant. Adding the 2dFGRS power spectrum constrains Omega_m h and breaks the degeneracy. If tensor anisotropies are assumed to be negligible, we obtain values for the Hubble constant h=0.665 +/- 0.047, the matter density Omega_m=0.313 +/- 0.055, and the physical CDM and baryon densities Omega_c h^2 = 0.115 +/- 0.009, Omega_b h^2 = 0.022 +/- 0.002 (standard rms errors). Including a possible tensor component causes very little change to these figures; we set a upper limit to the tensor-to-scalar ratio of r<0.7 at 95% confidence. We then show how these data can be used to constrain the equation of state of the vacuum, and find w<-0.52 at 95% confidence. The preferred cosmological model is thus very well specified, and we discuss the precision with which future CMB data can be predicted, given the model assumptions. The 2dFGRS power-spectrum data and covariance matrix, and the CMB data compilation used here, are available from http://www.roe.ac.uk/~wjp/

Will J. Percival; Will Sutherland; John A. Peacock; Carlton M. Baugh; Joss Bland-Hawthorn; Terry Bridges; Russell Cannon; Shaun Cole; Matthew Colless; Chris Collins; Warrick Couch; Gavin Dalton; Roberto De Propris; Simon P. Driver; George Efstathiou; Richard S. Ellis; Carlos S. Frenk; Karl Glazebrook; Carole Jackson; Ofer Lahav; Ian Lewis; Stuart Lumsden; Steve Maddox; Stephen Moody; Peder Norberg; Bruce A. Peterson; Keith Taylor

2002-08-22T23:59:59.000Z

Note: This page contains sample records for the topic "matter power spectrum" 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

The system architecting process for a solar power satellite concept.  

E-Print Network (OSTI)

??This thesis discusses the system architecting process for a Solar Power Satellite (SPS) concept.The heuristic approach allows a spectrum of concepts to be narrowed to… (more)

Bidwell, Joseph Grady

2006-01-01T23:59:59.000Z

222

Hawking spectrum and high frequency dispersion  

Science Journals Connector (OSTI)

We study the spectrum of created particles in two-dimensional black hole geometries for a linear, Hermitian scalar field satisfying a Lorentz noninvariant field equation with higher spatial derivative terms that are suppressed by powers of a fundamental momentum scale k0. The preferred frame is the "free-fall frame" of the black hole. This model is a variation of Unruh's sonic black hole analogy. We find that there are two qualitatively different types of particle production in this model: a thermal Hawking flux generated by "mode conversion" at the black hole horizon, and a nonthermal spectrum generated via scattering off the background into negative free-fall frequency modes. This second process has nothing to do with black holes and does not occur for the ordinary wave equation because such modes do not propagate outside the horizon with positive Killing frequency. The horizon component of the radiation is astonishingly close to a perfect thermal spectrum: for the smoothest metric studied, with Hawking temperature TH?0.0008k0, agreement is of order (THk0)3 at frequency ?=TH, and agreement to order THk0 persists out to ?TH?45 where the thermal number flux is ?10-20. The flux from scattering dominates at large ? and becomes many orders of magnitude larger than the horizon component for metrics with a "kink," i.e., a region of high curvature localized on a static world line outside the horizon. This nonthermal flux amounts to roughly 10% of the total luminosity for the kinkier metrics considered. The flux exhibits oscillations as a function of frequency which can be explained by interference between the various contributions to the flux.

Steven Corley and Ted Jacobson

1996-07-15T23:59:59.000Z

223

In the Matter of National Broadband Plan Request for Information:  

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

In the Matter of National Broadband Plan Request for Information: In the Matter of National Broadband Plan Request for Information: Communications Requirements In the Matter of National Broadband Plan Request for Information: Communications Requirements The American Public Power Association ("APPA") appreciates this opportunity to respond to the Department of Energy ("the Department" or "DOE") regarding its Request for Information ("RFI") on Implementing the National Broadband Plan by Studying the Communications Requirements of Electric Utilities to Inform Federal Smart Grid Policy. In the Matter of National Broadband Plan Request for Information: Communications Requirements More Documents & Publications Communications Requirements of Smart Grid Technologies RE: NBP RFI: Communications Requirements

224

Power and spectrum efficient communications in wireless ad hoc networks  

E-Print Network (OSTI)

on-cooperation message (AoC) with its own user ID included;requesting node receives the AoC message from a neighbor, it

Qu, Qi

2008-01-01T23:59:59.000Z

225

Electromagnetic Spectrum of Radium D  

Science Journals Connector (OSTI)

The electromagnetic spectrum of RaD has been studied by the proportional counter spectrometry technique. The work of the Curie Laboratory on the gamma-ray spectrum has been generally confirmed. However, the presumed K x-ray lines are of much lower intensity and occur at a lower energy than previously reported. The L x-ray intensity is 22 per hundred disintegrations, indicating 0.63 conversion per disintegration and a conversion coefficient of 18.3 for the principal gamma-ray.

P. E. Damon and R. R. Edwards

1953-04-15T23:59:59.000Z

226

Money Matters Parent Presentation  

E-Print Network (OSTI)

Money Matters Parent Presentation Presented by Becky Lore June 7, 2014 #12;Money Matters · Dates.fcac-acfc.gc.ca · Gail Vaz-Oxlade My Money, My Choices www.gailvazoxlade.com · Money Mentors www.moneymentors.ca/ · Money

Seldin, Jonathan P.

227

Spectrum Sensing Techniques in Cognitive Radio Communications  

E-Print Network (OSTI)

1 Spectrum Sensing Techniques in Cognitive Radio Communications Mario Bkassiny*, Yang Li, Georges for CR's. Index Terms-- Cognitive radio, cooperative spectrum sensing, dynamic spectrum access, energy, jayaweera, christos}@ece.unm.edu Abstract-- In this paper, we review some of the recent patents on spectrum

Jayaweera, Sudharman K.

228

Coalition Formation Games for Collaborative Spectrum Sensing  

E-Print Network (OSTI)

demand on the radio spectrum. However, the spectrum resources are scarce and most of them have been already licensed to existing operators. Various studies have shown that the actual licensed spectrum remains unoccupied for large periods [1]. For efficiently exploiting these spectrum holes, cognitive radio

Paris-Sud XI, Université de

229

Status of the large-scale dark-matter axion search  

SciTech Connect

If axions constitute the dark matter of our galactic halo they can be detected by their conversion into monochromatic microwave photons in a high-Q microwave cavity permeated by a strong magnetic field. A large-scale experiment is under construction at LLNL to search for halo axions in the mass range 1.3 - 13 {mu}eV, where axions may constitute closure density of the universe. The search builds upon two pilot efforts at BNL and the University of Florida in the late 1980`s, and represents a large improvement in power sensitivity ({approximately}50) both due to the increase in magnetic volume (B{sup 2}V = 14 T{sup 2}m{sup 3}), and anticipated total noise temperature (T{sub n} {approximately}3K). This search will also mark the first use of multiple power-combined cavities to extend the mass range accessible by this technique. Data will be analyzed in two parallel streams. In the first, the resolution of the power spectrum will be sufficient to resolve the expected width of the overall axion line, {approximately}{bigcirc} (1kHz). In the second, the resolution will be {bigcirc}(O.01-1 Hz) to look for extremely narrow substructure reflecting the primordial phase-space of the axions during infall. This experiment will be the first to have the required sensitivity to detect axions, for plausible axion models.

Van Bibber, K.; Hagmann, C.; Stoeffl, W. [Lawrence Livermore National Lab., CA (United States); Daw, E.; Rosenberg, L. [Massachusetts Institute of Technology, Cambridge, MA (United States). Dept. of Physics; Sikivie, P.; Sullivan, N.; Tanner, D. [Univ. of Florida, Gainesville, FL (United States). Dept. of Physics; Moltz, D.; Tighe, R. [Lawrence Berkeley Lab., CA (United States)] [and others

1994-09-01T23:59:59.000Z

230

Variable enstrophy flux and energy spectrum in two-dimensional turbulence with Ekman friction  

E-Print Network (OSTI)

Experiments and numerical simulations reveal that in the forward cascade regime, the energy spectrum of two-dimensional turbulence with Ekman friction deviates from Kraichnan's prediction of $k^{-3}$ power spectrum. In this letter we explain this observation using an analytic model based on variable enstrophy flux arising due to Ekman friction. We derive an expression for the enstrophy flux which exhibits a logarithmic dependence in the inertial range for the Ekman-friction dominated flows. The energy spectrum obtained using this enstrophy flux shows a power law scaling for large Reynolds number and small Ekman friction, but has an exponential behaviour for large Ekman friction and relatively small Reynolds number.

Mahendra K. Verma

2012-03-23T23:59:59.000Z

231

Smart Radio Spectrum Management for Cognitive Radio  

E-Print Network (OSTI)

Today's wireless networks are characterized by fixed spectrum assignment policy. The limited available spectrum and the inefficiency in the spectrum usage necessitate a new communication paradigm to exploit the existing wireless spectrum opportunistically. Cognitive radio is a paradigm for wireless communication in which either a network or a wireless node changes its transmission or reception parameters to communicate efficiently avoiding interference with licensed or unlicensed users. In this work, a fuzzy logic based system for spectrum management is proposed where the radio can share unused spectrum depending on some parameters like distance, signal strength, node velocity and availability of unused spectrum. The system is simulated and is found to give satisfactory results.

Bhattacharya, Partha Pratim; Gera, Rishita; Agarwal, Anjali

2011-01-01T23:59:59.000Z

232

Reconstruction of the primordial power spectra with Planck and BICEP2 data  

Science Journals Connector (OSTI)

By using the cubic spline interpolation method, we reconstruct the shape of the primordial scalar and tensor power spectra from the recently released Planck temperature and BICEP2 polarization cosmic microwave background data. We find that the vanishing scalar index running (dns/dlnk) model is strongly disfavored at more than 3? confidence level on the k=0.0002??Mpc?1 scale. Furthermore, the power-law parametrization gives a blue-tilt tensor spectrum, no matter using only the first five bandpowers nt=1.20?0.64+0.56(95%??C.L.) or the full nine bandpowers nt=1.24?0.58+0.51(95%??C.L.) of BICEP2 data sets. Unlike the large tensor-to-scalar ratio value (r?0.20) under the scale-invariant tensor spectrum assumption, our interpolation approach gives r0.002<0.060(95%??C.L.) by using the first five bandpowers of BICEP2 data. After comparing the results with/without BICEP2 data, we find that Planck temperature with small tensor amplitude signals and BICEP2 polarization data with large tensor amplitude signals dominate the tensor spectrum reconstruction on the large and small scales, respectively. Hence, the resulting blue tensor tilt actually reflects the tension between Planck and BICEP2 data.

Bin Hu; Jian-Wei Hu; Zong-Kuan Guo; Rong-Gen Cai

2014-07-30T23:59:59.000Z

233

Load Management and Houston Lighting and Power Co.  

E-Print Network (OSTI)

Defining Load Management as influencing of customer loads in order to shift the time use of electric power and energy, encompasses a broad spectrum of activities at Houston Lighting & Power Company. This paper describes those activities by directing...

Drawe, R. G.; Ramsay, I. M.

1984-01-01T23:59:59.000Z

234

A new life for sterile neutrinos: resolving inconsistencies using hot dark matter  

SciTech Connect

Within the standard ?CDM model of cosmology, the recent Planck measurements have shown discrepancies with other observations, e.g., measurements of the current expansion rate H{sub 0}, the galaxy shear power spectrum and counts of galaxy clusters. We show that if ?CDM is extended by a hot dark matter component, which could be interpreted as a sterile neutrino, the data sets can be combined consistently. A combination of Planck data, WMAP-9 polarisation data, measurements of the BAO scale, the HST measurement of H{sub 0}, Planck galaxy cluster counts and galaxy shear data from the CFHTLens survey yields ?N{sub eff} = 0.61±0.30 and m{sub s}{sup eff} = (0.41±0.13)eV at 1?. The former is driven mainly by the large H{sub 0} of the HST measurement, while the latter is driven by cluster data. CFHTLens galaxy shear data prefer ?N{sub eff}> 0 and a non-zero mass. Taken together, we find hints for the presence of a hot dark matter component at 3?. A sterile neutrino motivated by the reactor and gallium anomalies appears rejected at even higher significance and an accelerator anomaly sterile neutrino is found in tension at 2?.

Hamann, Jan [Theory Division, Physics Department CERN, CH-1211 Geneva 23 (Switzerland); Hasenkamp, Jasper, E-mail: jan.hamann@cern.ch, E-mail: jasper.hasenkamp@nyu.edu [Center for Cosmology and Particle Physics, Physics Department New York University, New York, NY 10003 (United States)

2013-10-01T23:59:59.000Z

235

On the Oscillation of Neutrinos Produced by the Annihilation of Dark Matter inside the Sun  

E-Print Network (OSTI)

The annihilation of dark matter particles captured by the Sun can lead to a neutrino flux observable in neutrino detectors. Considering the fact that these dark matter particles are non-relativistic, if a pair of dark matter annihilates to a neutrino pair, the spectrum of neutrinos will be monochromatic. We show that in this case, even after averaging over production point inside the Sun, the oscillatory terms of the oscillation probability do not average to zero. This leads to interesting observable features in the annual variation of the number of muon track events. We show that smearing of the spectrum due to thermal distribution of dark matter inside the Sun is too small to wash out this variation. We point out the possibility of studying the initial flavor composition of neutrinos produced by the annihilation of dark matter particles via measuring the annual variation of the number of muon-track events in neutrino telescopes.

Arman Esmaili; Yasaman Farzan

2009-12-20T23:59:59.000Z

236

Cosmic-ray electron signatures of dark matter  

SciTech Connect

There is evidence for an excess in cosmic-ray electrons at about 500 GeV energy, that may be related to dark-matter annihilation. I have calculated the expected electron contributions from a pulsar and from Kaluza-Klein dark matter, based on a realistic treatment of the electron propagation in the Galaxy. Pulsars younger than about 10{sup 5} years naturally cause a narrow peak at a few hundred GeV in the locally observed electron spectrum, similar to that observed. On the other hand, if electron production by dark matter is predominantly occurring in high-mass clumps (> or approx. 10{sup 3}M{sub {center_dot}}), the sharp cutoff in the contribution from Kaluza-Klein particles is sometimes more pronounced, but often smoothed out and indistinguishable from a pulsar source, and therefore the spectral shape of the electron excess is insufficient to discriminate a dark-matter origin from more conventional astrophysical explanations.

Pohl, Martin [Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011 (United States)

2009-02-15T23:59:59.000Z

237

Matter Waves and Electricity  

Science Journals Connector (OSTI)

Classical four-dimensional relativity gives a most natural and harmonious interpretation of the three basic phenomena of nature: gravity, electricity, and the wave structure of matter, provided that the basic assumptions of the Einsteinian theory are modified in two respects: (1) the fundamental invariant of the action principle is chosen as a quadratic instead of a linear function of the curvature components; (2) the static equilibrium of the world is replaced by a dynamic equilibrium. Electricity comes out as a second-order resonance effect of the matter waves. The matter waves are gravitational waves but superposed not on an empty Euclidean space but on a space of high average curvature.

Cornelius Lanczos

1942-06-01T23:59:59.000Z

238

Wind noise and the spectrum of atmospheric turbulence pressure fluctuations  

Science Journals Connector (OSTI)

Previous research [S. Morgan and R. Raspet J. Acoust. Soc. Am. 92 1180–1183 (1992)] has shown that wind noise is predominantly caused by pressure fluctuations intrinsic to the turbulent atmospheric flow. Therefore it should be possible to predict wind noise from models for turbulent pressure spectra in the atmosphere. Based on simple dimensional analysis and an application of Taylor’s hypothesis the inertial?subrange power spectrum for turbulent pressure fluctuations should be proportional to f ?7/3 where f is frequency. But more recent atmospheric observations and theoretical arguments [J. D. Albertson G. G. Katul M. B. Parlange and W. E. Eichinger Phys. Fluids 10 1725–1732 (1998)] suggest that the power spectrum actually goes as f ?3/2. In this paper it is shown that the f ?3/2 dependence predicts a much slower decay in wind noise with increasing acoustic frequency than is typically observed. Possible reasons for this discrepancy are discussed.

2003-01-01T23:59:59.000Z

239

Hot and dark matter  

E-Print Network (OSTI)

In this thesis, we build new Effective Field Theory tools to describe the propagation of energetic partons in hot and dense media, and we propose two new reactions for dark matter in the early universe. In the first part, ...

D'Eramo, Francesco

2012-01-01T23:59:59.000Z

240

The Heart of Matter  

E-Print Network (OSTI)

In this article I trace the development of the human understanding of the "Heart of Matter" from early concepts of "elements" (or alternatively "Panchmahabhootas") to the current status of "quarks" and "leptons" as the fundamental constituents of matter, interacting together via exchange of the various force carrier particles called "gauge bosons" such as the photon, W/Z-boson etc. I would like to show how our understanding of the fundamental constituents of matter has gone hand in hand with our understanding of the fundamental forces in nature. I will also outline how the knowledge of particle physics at the "micro" scale of less than a Fermi(one millionth of a nanometer), enables us to offer explanations of Cosmological observations at the "macro" scale. Consequently these observations, may in turn, help us address some very fundamental questions of the Physics at the "Heart of the Matter".

Godbole, Rohini M

2010-01-01T23:59:59.000Z

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241

The Heart of Matter  

E-Print Network (OSTI)

In this article I trace the development of the human understanding of the "Heart of Matter" from early concepts of "elements" (or alternatively "Panchmahabhootas") to the current status of "quarks" and "leptons" as the fundamental constituents of matter, interacting together via exchange of the various force carrier particles called "gauge bosons" such as the photon, W/Z-boson etc. I would like to show how our understanding of the fundamental constituents of matter has gone hand in hand with our understanding of the fundamental forces in nature. I will also outline how the knowledge of particle physics at the "micro" scale of less than a Fermi(one millionth of a nanometer), enables us to offer explanations of Cosmological observations at the "macro" scale. Consequently these observations, may in turn, help us address some very fundamental questions of the Physics at the "Heart of the Matter".

Rohini M. Godbole

2010-06-30T23:59:59.000Z

242

Atomic dark matter  

SciTech Connect

We propose that dark matter is dominantly comprised of atomic bound states. We build a simple model and map the parameter space that results in the early universe formation of hydrogen-like dark atoms. We find that atomic dark matter has interesting implications for cosmology as well as direct detection: Weak-scale dark atoms can accommodate hyperfine splittings of order 100 keV, consistent with the inelastic dark matter interpretation of the DAMA data while naturally evading direct detection bounds. Moreover, protohalo formation can be suppressed below M{sub proto} ? 10{sup 3}–10{sup 6}M{sub s}un for weak scale dark matter due to Ion-Radiation and Ion-Atom interactions in the dark sector.

Kaplan, David E.; Krnjaic, Gordan Z.; Rehermann, Keith R.; Wells, Christopher M., E-mail: dkaplan@pha.jhu.edu, E-mail: gordan@pha.jhu.edu, E-mail: keith@pha.jhu.edu, E-mail: cwells13@pha.jhu.edu [Department of Physics and Astronomy, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218-2686 (United States)

2010-05-01T23:59:59.000Z

243

Towards Cognitive Radio Networks: Spectrum Utilization Measurements in Suburb Environment  

E-Print Network (OSTI)

Towards Cognitive Radio Networks: Spectrum Utilization Measurements in Suburb Environment Václav in an opportunistic way. Cognitive radio concept for better spectrum utilization is introduced here along -- Cognitive radio, radio spectrum management, spectrum sensing, spectrum utilization. I. INTRODUCTION

Paris-Sud XI, Université de

244

Dark matter identification with gamma rays from dwarf galaxies  

SciTech Connect

If the positron fraction and combined electron-positron flux excesses recently observed by PAMELA, Fermi and HESS are due to dark matter annihilation into lepton-rich final states, the accompanying final state radiation (FSR) photons may be detected by ground-based atmospheric Cherenkov telescopes (ACTs). Satellite dwarf galaxies in the vicinity of the Milky Way are particularly promising targets for this search. We find that current and near-future ACTs have an excellent potential for discovering the FSR photons from dwarfs, although a discovery cannot be guaranteed due to large uncertainties in the fluxes resulting from lack of precise knowledge of dark matter distribution within the dwarfs. We also investigate the possibility of discriminating between different dark matter models based on the measured FSR photon spectrum. For typical parameters, we find that the ACTs can reliably distinguish models predicting dark matter annihilation into two-lepton final states from those favoring four-lepton final states (as in, for example, ''axion portal'' models). In addition, we find that the dark matter particle mass can also be determined from the FSR spectrum.

Perelstein, Maxim; Shakya, Bibhushan, E-mail: mp325@cornell.edu, E-mail: bs475@cornell.edu [Institute for High Energy Phenomenology, Newman Laboratory of Elementary Particle Physics, Cornell University, Ithaca, NY 14853 (United States)

2010-10-01T23:59:59.000Z

245

Neutrinos at IceCube from heavy decaying dark matter  

Science Journals Connector (OSTI)

A monochromatic line in the cosmic neutrino spectrum would be a smoking gun signature of dark matter. It is intriguing that the IceCube experiment has recently reported two PeV neutrino events with energies that may be equal up to experimental uncertainties, and which have a probability of being a background fluctuation estimated to be less than a percent. Here we explore prospects for these events to be the first indication of a monochromatic line signal from dark matter. While measurable annihilation signatures would seem to be impossible at such energies, we discuss the dark matter quantum numbers, effective operators, and lifetimes which could lead to an appropriate signal from dark matter decays. We will show that the set of possible decay operators is rather constrained and will focus on the following viable candidates which could explain the IceCube events: R-parity violating gravitinos, hidden sector gauge bosons, and singlet fermions in an extra dimension. In essentially all cases we find that a PeV neutrino line signal from dark matter would be accompanied by a potentially observable continuum spectrum of neutrinos rising towards lower energies.

Brian Feldstein; Alexander Kusenko; Shigeki Matsumoto; Tsutomu T. Yanagida

2013-07-02T23:59:59.000Z

246

Public safety radios must pool spectrum  

E-Print Network (OSTI)

The dynamic-spectrum-access research and development community is maturing technologies that will enable radios to share RF spectrum much more intensively. The adoption of DSA technologies by the public-safety community ...

Lehr, William Herndon

247

PowerPoint Presentation  

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

Energy Materials Energy Materials Advanced Energy Materials Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory A bird's eye view is provided of superconducting and thermoelectric materials research at the Advanced Energy Materials Group*. We study both the microscopic and macroscopic properties of complex and nano-structured materials and develop their application in energy related technologies. Abstract Abstract Abstract are capable of carrying electrical current without loss, and hence offer powerful opportunities for increasing the capacity and efficiency of the power grid. The superconducting materials program at BNL studies the basic relationships between structure and properties of superconductors to provide understanding of fundamental materials science and physics

248

Spectrum Characterization for Opportunistic Cognitive Radio Systems  

E-Print Network (OSTI)

1 Spectrum Characterization for Opportunistic Cognitive Radio Systems Tevfik Y¨ucek and H challenging problems in cognitive radio systems. The spectrum of interest needs to be characterized and unused initial network entry is also discussed as a case study. Index Terms-- Cognitive radio, spectrum sensing

Arslan, Hüseyin

249

Energy Spectrum of the Soft Component near Sea Level  

Science Journals Connector (OSTI)

An analysis of the transition curves of Carmichael and Steljes has been carried out to yield the transition curves in lead of ion-chamber bursts produced by cascades initiated by the electrons and photons of the soft component incident from the atmosphere. From the rates at the maxima of these transition curves, the absolute omnidirectional integral energy spectrum of the electrons and photons of the soft component at sea level, in the energy range from about 100 Mev to 100 Bev, is deduced. Incident electrons and photons associated with extensive air showers, as identified by coincidences with a nearby larger ion chamber, are excluded. An additional single experimental point on the integral spectrum (8.4×10-3 per sphere of unit area per sec) is obtained from the observed rate of electrons of all energies greater than 1 Mev which intersect the unshielded ion chamber. Since a quantitative relation from electromagnetic cascade theory is made use of in the derivation of the energy spectrum, and since this relation is at present uncertain for lead in the energy range involved, the possible error of the flux in the energy spectrum (±100%) is much larger than that of the observed rates of occurrence of bursts (±5%). In this respect the spectrum is preliminary only. In the energy range below 400 Mev the integral spectrum is in agreement with previous absolute measurements; below 2 Bev it is in conformity with a previous relative measurement; from 1.6 Bev to 100 Bev, where there are no previous determinations, it obeys a power law of exponent -2.00 and the rate for 1.6 Bev is 2.4×10-5 per sphere of unit area per sec.

Hugh Carmichael

1957-09-01T23:59:59.000Z

250

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

251

Hybrid spread spectrum radio system  

DOE Patents (OSTI)

Systems and methods are described for hybrid spread spectrum radio systems. A method includes modulating a signal by utilizing a subset of bits from a pseudo-random code generator to control an amplification circuit that provides a gain to the signal. Another method includes: modulating a signal by utilizing a subset of bits from a pseudo-random code generator to control a fast hopping frequency synthesizer; and fast frequency hopping the signal with the fast hopping frequency synthesizer, wherein multiple frequency hops occur within a single data-bit time.

Smith, Stephen F. (London, TN); Dress, William B. (Camas, WA)

2010-02-02T23:59:59.000Z

252

Materials/Condensed Matter  

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

Materials/Condensed Matter Print Materials/Condensed Matter Print Materials research provides the foundation on which the economic well being of our high-tech society rests. The impact of advanced materials ranges dramatically over every aspect of our modern world from the minutiae of daily life to the grand scale of our national economy. Invariably, however, breakthroughs to new technologies trace their origin both to fundamental research in the basic properties of condensed matter and to applied research aimed at manipulating properties (structural, physical, chemical, electrical, magnetic, optical, etc.). Increasingly, the frontiers of materials research include materials that are "strongly correlated," characterized by strong coupling between a material's electrons with other electrons, magnetism, or the material lattice itself. This coupling often results in novel behavior, such as superconductivity, that may lead to technologically important applications.

253

Thermodynamics of clusterized matter  

E-Print Network (OSTI)

Thermodynamics of clusterized matter is studied in the framework of statistical models with non-interacting cluster degrees of freedom. At variance with the analytical Fisher model, exact Metropolis simulation results indicate that the transition from homogeneous to clusterized matter lies along the $\\rho=\\rho_0$ axis at all temperatures and the limiting point of the phase diagram is not a critical point even if the surface energy vanishes at this point. Sensitivity of the inferred phase diagram to the employed statistical framework in the case of finite systems is discussed by considering the grand-canonical and constant-pressure canonical ensembles. A Wigner-Seitz formalism in which the fragment charge is neutralized by an uniform electron distribution allows to build the phase diagram of neutron star matter.

Ad. R. Raduta; F. Gulminelli

2009-02-28T23:59:59.000Z

254

SPARTA: Stable and Efficient Spectrum Access in Next Generation Dynamic Spectrum Networks  

E-Print Network (OSTI)

and development require easy and reliable access to radio spectrum. However, exist- ing regulations allocateSPARTA: Stable and Efficient Spectrum Access in Next Generation Dynamic Spectrum Networks Lili Cao.S.A Abstract--Future wireless infrastructure networks will dynam- ically access spectrum for maximum

Almeroth, Kevin C.

255

Joint Spectrum Allocation and Scheduling for Fair Spectrum Sharing in Cognitive Radio  

E-Print Network (OSTI)

Joint Spectrum Allocation and Scheduling for Fair Spectrum Sharing in Cognitive Radio Wireless University, Tempe, AZ 85287-8809. Email:{misra,xue}@asu.edu Abstract Cognitive radio and Dynamic Spectrum joint spectrum alloca- tion and scheduling problems in cognitive radio wireless networks with the objec

Misra, Satyajayant

256

Determination of a mutational spectrum  

DOE Patents (OSTI)

A method of resolving (physically separating) mutant DNA from nonmutant DNA and a method of defining or establishing a mutational spectrum or profile of alterations present in nucleic acid sequences from a sample to be analyzed, such as a tissue or body fluid. The present method is based on the fact that it is possible, through the use of DGGE, to separate nucleic acid sequences which differ by only a single base change and on the ability to detect the separate mutant molecules. The present invention, in another aspect, relates to a method for determining a mutational spectrum in a DNA sequence of interest present in a population of cells. The method of the present invention is useful as a diagnostic or analytical tool in forensic science in assessing environmental and/or occupational exposures to potentially genetically toxic materials (also referred to as potential mutagens); in biotechnology, particularly in the study of the relationship between the amino acid sequence of enzymes and other biologically-active proteins or protein-containing substances and their respective functions; and in determining the effects of drugs, cosmetics and other chemicals for which toxicity data must be obtained.

Thilly, William G. (Winchester, MA); Keohavong, Phouthone (Cambridge, MA)

1991-01-01T23:59:59.000Z

257

Short range spread-spectrum radiolocation system and method  

DOE Patents (OSTI)

A short range radiolocation system and associated methods that allow the location of an item, such as equipment, containers, pallets, vehicles, or personnel, within a defined area. A small, battery powered, self-contained tag is provided to an item to be located. The tag includes a spread-spectrum transmitter that transmits a spread-spectrum code and identification information. A plurality of receivers positioned about the area receive signals from a transmitting tag. The position of the tag, and hence the item, is located by triangulation. The system employs three different ranging techniques for providing coarse, intermediate, and fine spatial position resolution. Coarse positioning information is provided by use of direct-sequence code phase transmitted as a spread-spectrum signal. Intermediate positioning information is provided by the use of a difference signal transmitted with the direct-sequence spread-spectrum code. Fine positioning information is provided by use of carrier phase measurements. An algorithm is employed to combine the three data sets to provide accurate location measurements.

Smith, Stephen F. (Loudon, TN)

2003-04-29T23:59:59.000Z

258

Tunguska Dark Matter Ball  

E-Print Network (OSTI)

It is suggested that the Tunguska event in June 1908 cm-large was due to a cm-large ball of a condensate of bound states of 6 top and 6 anti-top quarks containing highly compressed ordinary matter. Such balls are supposed to make up the dark matter as we earlier proposed. The expected rate of impact of this kind of dark matter ball with the earth seems to crudely match a time scale of 200 years between the impacts. The main explosion of the Tunguska event is explained in our picture as material coming out from deep within the earth, where it has been heated and compressed by the ball penetrating to a depth of several thousand km. Thus the effect has some similarity with volcanic activity as suggested by Kundt. We discuss the possible identification of kimberlite pipes with earlier Tunguska-like events. A discussion of how the dark matter balls may have formed in the early universe is also given.

C. D. Froggatt; H. B. Nielsen

2014-03-27T23:59:59.000Z

259

Tunguska Dark Matter Ball  

E-Print Network (OSTI)

It is suggested that the Tunguska event in June 1908 cm-large was due to a cm-large ball of a condensate of bound states of 6 top and 6 anti-top quarks containing highly compressed ordinary matter. Such balls are supposed to make up the dark matter as we earlier proposed. The expected rate of impact of this kind of dark matter ball with the earth seems to crudely match a time scale of 200 years between the impacts. The main explosion of the Tunguska event is explained in our picture as material coming out from deep within the earth, where it has been heated and compressed by the ball penetrating to a depth of several thousand km. Thus the effect has some similarity with volcanic activity as suggested by Kundt. We discuss the possible identification of kimberlite pipes with earlier Tunguska-like events. A discussion of how the dark matter balls may have formed in the early universe is also given.

Froggatt, C D

2014-01-01T23:59:59.000Z

260

Matter & Energy Nanotechnology  

E-Print Network (OSTI)

See also: Matter & Energy Nanotechnology Civil Engineering Chemistry Computers & Math Computer www.carbodeon.com Nanotechnology afm Perform better live cell research! Non-invasive, in-liquid AFM cures Had flu? You m Science News Share Blog Cite Health & Medicine Mind & Brain Plants & Animals Earth

Espinosa, Horacio D.

Note: This page contains sample records for the topic "matter power spectrum" 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

Matter & Energy Wind Energy  

E-Print Network (OSTI)

See Also: Matter & Energy Wind Energy Energy Technology Physics Nuclear Energy Petroleum 27, 2012) -- Energy flowing from large-scale to small-scale places may be prevented from flowing, indicating that there are energy flows from large to small scale in confined space. Indeed, under a specific

Shepelyansky, Dima

262

Matter & Energy Solar Energy  

E-Print Network (OSTI)

See Also: Matter & Energy Solar Energy· Electronics· Materials Science· Earth & Climate Energy and the Environment · Renewable Energy· Environmental Science · Reference Chemical compound· Semiconductor· Gallium at the University of Illinois, the future of solar energy just got brighter. Although silicon is the industry

Rogers, John A.

263

Matter & Energy Engineering  

E-Print Network (OSTI)

. AmericanEnergyProperties.com Related Stories New Facility BoostsGasHydrates Research (June 2, 2008) --A new & Climate Global Warming Environmental Issues Climate Reference Natural gas Hydrocarbon Automobile emissionsLike 6 0 | More APA MLA See Also: Matter & Energy Petroleum Engineering Fossil Fuels Earth

Sóbester, András

264

Dark matter, not magnetism  

Science Journals Connector (OSTI)

......Astronomical Society. Provided by the NASA Astrophysics Data System 1 March 1993 research-article Letters Dark matter, not magnetism Massimo Persic 1 2 Paolo Salucci 1 1 Notice that most optical rotation curves, coming from the gas-emitted H alpha line......

Massimo Persic; Paolo Salucci

1993-03-01T23:59:59.000Z

265

Electric power annual 1992  

SciTech Connect

The Electric Power Annual presents a summary of electric utility statistics at national, regional and State levels. The objective of the publication is to provide industry decisionmakers, government policymakers, analysts and the general public with historical data that may be used in understanding US electricity markets. The Electric Power Annual is prepared by the Survey Management Division; Office of Coal, Nuclear, Electric and Alternate Fuels; Energy Information Administration (EIA); US Department of Energy. ``The US Electric Power Industry at a Glance`` section presents a profile of the electric power industry ownership and performance, and a review of key statistics for the year. Subsequent sections present data on generating capability, including proposed capability additions; net generation; fossil-fuel statistics; retail sales; revenue; financial statistics; environmental statistics; electric power transactions; demand-side management; and nonutility power producers. In addition, the appendices provide supplemental data on major disturbances and unusual occurrences in US electricity power systems. Each section contains related text and tables and refers the reader to the appropriate publication that contains more detailed data on the subject matter. Monetary values in this publication are expressed in nominal terms.

Not Available

1994-01-06T23:59:59.000Z

266

High power  

Science Journals Connector (OSTI)

... 1970s technomanic projects such as nuclear power stations were still in vogue. Environmentalists argued that solar power seemed a far safer, cheaper and reassuringly low-tech power source. The technomaniacs ... tech power source. The technomaniacs, fearing that they were losingthis argument, sought to hijack solar power themselves. They proposed an enormously expensive and complicated ...

David Jones

1994-03-03T23:59:59.000Z

267

Radiative ablation to low-Z matter  

Science Journals Connector (OSTI)

Eight beams of 0.35-?m laser with pulse duration of about 1.0 ns and energy of 260 J per beam were injected into a cylindrical cavity to generate intense x-ray radiation on the Shengguang II high power laser facility. Plastic foils with a thickness in the range of about 3.0–45 ?m were attached on the diagnostic hole of the cavity and ablated by the intense x-ray radiation. The radiative energy transport through plastic foils with different thicknesses has been studied experimentally. The burn-through time of the plastic foils has been obtained. For comparison, we also simulated the experimental results with Planckian and non-Planckian x-ray spectrum source, respectively. It is shown that for thick plastic foil the simulation with non-Planckian x-ray spectrum source is in good agreement with the experiment.

Jiamin Yang; Jiatian Sheng; Yaonan Ding; Yunsheng Li; Shaoen Jiang; Tinggui Feng; Zhijian Zheng; Kexu Sun; Wenghai Zhang; Yanli Cui; Jiushen Cheng

2002-09-30T23:59:59.000Z

268

Dark Matter Gravitational Interactions  

E-Print Network (OSTI)

We argue that the conjectured dark mater in the Universe may be endowed with a new kind of gravitational charge that couples to a short range gravitational interaction mediated by a massive vector field. A model is constructed that assimilates this concept into ideas of current inflationary cosmology. The model is also consistent with the observed behaviour of galactic rotation curves according to Newtonian dynamics. The essential idea is that stars composed of ordinary (as opposed to dark matter) experience Newtonian forces due to the presence of an all pervading background of massive gravitationally charged cold dark matter. The novel gravitational interactions are predicted to have a significant influence on pre-inflationary cosmology. The precise details depend on the nature of a gravitational Proca interaction and the description of matter. A gravitational Proca field configuration that gives rise to attractive forces between dark matter charges of like polarity exhibits homogeneous isotropic eternal cosmologies that are free of cosmological curvature singularities thus eliminating the horizon problem associated with the standard big-bang scenario. Such solutions do however admit dense hot pre-inflationary epochs each with a characteristic scale factor that may be correlated with the dark matter density in the current era of expansion. The model is based on a theory in which a modification of Einsteinian gravity at very short distances can be expressed in terms of the gradient of the Einstein metric and the torsion of a non-Riemannian connection on the bundle of linear frames over spacetime. Indeed we demonstrate that the genesis of the model resides in a remarkable simplification that occurs when one analyses the variational equations associated with a broad class of non-Riemannian actions.

R. W. Tucker; C. Wang

1996-12-09T23:59:59.000Z

269

Energy Matters in Washington State Page 1 Energy Matters  

E-Print Network (OSTI)

Energy Matters in Washington State ­ Page 1 Energy Matters in Washington State June 2008 Updated November 2009 Updated and Revised October 2013 Grand Coulee Dam #12;Energy Matters in Washington State ­ Page 2 Copyright © 2013 Washington State University Energy Program. 905 Plum Street SE, P.O. Box 43169

Collins, Gary S.

270

Power Marketing  

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

UGPS' Marketing Service Area Power Marketing As a marketer of Federal power in the Upper Great Plains Region, the Power Marketing staff provides a variety of services for customers...

271

The Search for Dark Matter  

ScienceCinema (OSTI)

More than 25 years ago, PNNL scientists began the first underground measurements searching for dark matter using specialized radiation detector technology. Dark matter is yet to be discovered says Physicist John L. Orrell.

Orrell, John

2014-07-24T23:59:59.000Z

272

The Search for Dark Matter  

SciTech Connect

More than 25 years ago, PNNL scientists began the first underground measurements searching for dark matter using specialized radiation detector technology. Dark matter is yet to be discovered says Physicist John L. Orrell.

Orrell, John

2013-11-20T23:59:59.000Z

273

Spectrum Auction Framework for Access Allocation in Cognitive Radio Networks  

E-Print Network (OSTI)

1 Spectrum Auction Framework for Access Allocation in Cognitive Radio Networks Gaurav S. Kasbekar does not exist. Index Terms Cognitive Radio Networks, Spectrum Auctions, Algorithms I. INTRODUCTION, Wireless Meteropolitan Area networks etc., demand for radio spectrum is increasing. Currently, spectrum

Sarkar, Saswati

274

Direct search for dark matter  

SciTech Connect

Dark matter is hypothetical matter which does not interact with electromagnetic radiation. The existence of dark matter is only inferred from gravitational effects of astrophysical observations to explain the missing mass component of the Universe. Weakly Interacting Massive Particles are currently the most popular candidate to explain the missing mass component. I review the current status of experimental searches of dark matter through direct detection using terrestrial detectors.

Yoo, Jonghee; /Fermilab

2009-12-01T23:59:59.000Z

275

The radio spectrum of Sgr A*  

E-Print Network (OSTI)

We discuss the radio spectrum of Sgr A* \\index{Sgr A*, radio spectrum} in the frequency range between $\\approx 1\\,{\\rm GHz}$ and $\\approx 1\\,000\\,{\\rm GHz}$, show that it can be explained by optically thin synchrotron radiation \\index{Sgr A*, synchrotron radiation, optically thin} of relativistic electrons, and point toward a possible correlation between the spectrum of Sgr A* and larger-scale ($\\la 50\\,{\\rm pc}$) radio emission from the Galactic Center \\index{Galactic Center} region.

Wolfgang J. Duschl; Harald Lesch

1994-11-03T23:59:59.000Z

276

Supernovae and Gamma-Ray Bursts Powered by Hot Neutrino-Cooled Coronae  

E-Print Network (OSTI)

Cosmological explosions such as core-collapse supernovae (SNe) and gamma-ray bursts (GRBs) are thought to be powered by the rapid conversion of roughly a solar mass' worth of gravitational binding energy into a comparatively small amount of outgoing observable kinetic energy. A fractional absorption of the emitted neutrinos, the particles which carry away the binding energy, by the expelled matter is a widely discussed mechanism for powering such explosions. Previous work addressing neutrino emission from core-collapse like environments assumes that the outgoing neutrino spectrum closely resembles a black body whose effective temperature is determined by both the rate of energy release and the surface area of the entire body. Unfortunately, this assumption minimizes the net efficiency for both neutrino-driven explosion mechanisms. Motivated by this fact, we qualitatively outline a scenario where a hot corona deforms the neutrino spectrum away from that of a cool thermal emitter. Our primary result is that in principle, a coronal-driven explosion mechanism can enhance the net efficiency of neutrino-driven SNe and GRBs by more than an order of magnitude.

Enrico Ramirez-Ruiz; Aristotle Socrates

2005-04-11T23:59:59.000Z

277

Particulate matter dynamics  

E-Print Network (OSTI)

A substantial fraction of the particulate matter released into the atmosphere by industrial or natural processes corresponds to particles whose aerodynamic diameters are greater than 50 mm. It has been shown that, for these particles, the classical description of Gaussian plume diffusion processes, is inadequate to describe the transport and deposition. In this paper we present new results concerning the dispersion of coarse particulate matter. The simulations are done with our own code that uses the Bulirsch Stoer numerical integrator to calculate threedimensional trajectories of particles released into the environment under very general conditions. Turbulent processes are simulated by the Langevin equation and weather conditions are modeled after stable (Monin-Obukhov length L> 0) and unstable conditions (L <0). We present several case studies based on Monte Carlo simulations and discusses the effect of weather on the final deposition of these particles.

Cionco, Rodolfo G; Caligaris, Marta G

2012-01-01T23:59:59.000Z

278

Cognitive radio networks for dynamic spectrum management.  

E-Print Network (OSTI)

??A fundamental evolution is witnessed in recent research and development of wireless communications: much effort is put on shifting from the current static spectrum management… (more)

Jia, Juncheng

2009-01-01T23:59:59.000Z

279

Proceedings of the IEEE, vol. 97, no. 4, pp. 708-19, April 2009. Sharing Spectrum through Spectrum Policy Reform  

E-Print Network (OSTI)

Spectrum Policy Reform and Cognitive Radio1 Jon M. Peha Carnegie Mellon University Abstract Traditionally inefficient use of spectrum. Cognitive radio along with software radio, spectrum sensors, mesh networks sharing, spectrum policy, cognitive radio, band manager, unlicensed, etiquette, opportunistic access

Peha, Jon M.

280

Investment and Pricing with Spectrum Uncertainty: A Cognitive Operator's Perspective  

E-Print Network (OSTI)

" of licensed bands and dynamically leasing from the spectrum owner. As a result, a C-MVNO can make flexible--Cognitive radio, spectrum trading, spectrum sensing, dynamic spectrum leasing, spectrum pricing, Stackelberg game affecting the normal oper- ation of the spectrum owner who serves the primary (licensed) users. Dynamic

Huang, Jianwei

Note: This page contains sample records for the topic "matter power spectrum" 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

Brookhaven Condensed Matter Physics  

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

Condensed Matter Physics Condensed Matter Physics Condensed matter physicists study the properties of bulk matter-solids and liquids-as well as the properties exhibited at surfaces and interfaces, with a view to obtaining a fundamental understanding of the unusual properties that materials can exhibit. These problems are some of the most challenging in physics today, but have the huge pay-off in that such an understanding may ultimately lead to improved materials for use in applications as diverse as computing, memory storage, electric motors, and energy storage and transport. At Brookhaven Lab, this work includes both experimental and theoretical studies. Much of the experimental work carried out today uses the National Synchrotron Light Source (NSLS, shown at right)-one of the premiere synchrotron light sources of the last two decades. Commissioned in the 1980s, the NSLS is host to more than 2,200 users per year and produces copious amounts of light, from the infrared to the ultraviolet to the x-ray. By using this light as a probe, scientists can learn about the arrangement of the atoms and electrons in the materials and how they behave under various conditions. Among other projects, BNL scientists have played leading roles in the development and application of resonant and inelastic x-ray scattering techniques to the study of magnetic and other materials, have pioneered the use of photoemission techniques (based on the photoelectric effect that Einstein first understood 100 years ago) for looking at electronic and magnetic materials, and have carried out some of the seminal experiments to understand the atomic and magnetic structure at surfaces.

282

Ankle phenomenon in the cosmic ray energy spectrum  

E-Print Network (OSTI)

The author has suggested that the knee phenomenon in the cosmic ray energy spectrum at 3 PeV can be explained as a split between a radiation-dominated expansion and a matter-dominated expansion of an expanding heat bath. The model proposed in 1985, in fact, predicted that high energy cosmic rays are emitted from AGN, massive black holes, in agreement with recent data from the Pierre Auger Observatory. Similarly, the ankle phenomenon at 3 EeV is shown to be explained by a split between inflational expansion and ordinary material expansion of the expanding heat bath, not unlike that in the expansion of the universe. All the spectral indicies in the respective regions of the energy spectra agree with the theoretical calculation from the respective expansion rates.

Yukio Tomozawa

2012-08-22T23:59:59.000Z

283

Ankle phenomenon in the cosmic ray energy spectrum  

E-Print Network (OSTI)

The author has suggested that the knee phenomenon in the cosmic ray energy spectrum at 3 PeV can be explained as a split between a radiation-dominated expansion and a matter-dominated expansion of an expanding heat bath. The model proposed in 1985, in fact, predicted that high energy cosmic rays are emitted from AGN, massive black holes, in agreement with recent data from the Pierre Auger Observatory. Similarly, the ankle phenomenon at 3 EeV is shown to be explained by a split between inflational expansion and ordinary material expansion of the expanding heat bath, not unlike that in the expansion of the universe. All the spectral indicies in the respective regions of the energy spectra agree with the theoretical calculation from the respective expansion rates.

Tomozawa, Yukio

2012-01-01T23:59:59.000Z

284

Climate Change, Nuclear Power and Nuclear  

E-Print Network (OSTI)

Climate Change, Nuclear Power and Nuclear Proliferation: Magnitude Matters Rob Goldston MIT IAP biomass wind hydro coal CCS coal nat gas CCS nat gas nuclear Gen IV nuclear Gen III nuclear Gen II 5-1 Electricity Generation: CCS and Nuclear Power Technology Options Available Global Electricity Generation WRE

285

Hardening Neutron Spectrum for Advanced Actinides Transmutation Experiments in the ATR  

SciTech Connect

The most effective method for transmuting long-lived isotopes contained in spent nuclear fuel into shorter-lived fission products is in a fast neutron spectrum reactor. In the absence of a fast rest reactor in the United States, initial irradiation testing of candidate fuels can be performed in a thermal test reactor that has been modified to produce a test region with a hardened neutron spectrum. Such a test facility, with a spectrum similar but somewhat softer than that of the liquid-metal fast breeder reactor (LMFBR), has been constructed in the INEEL's Advanced Test Reactor (ATR). The radial fission power distribution of the actinide fuel pin, which is an important parameter in fission gas released modelling, needs to be accurately predicted and the hardened neturon spectrum in the ATR and the LMFBR fast neutron spectrum is compared. The comparison analyses in this study are peformed using MCWO, a well-developed tool that couples the Monte Carlo transport code MCNP with the isotope depletion and build-up code ORIGEN-2. MCWO analysis yields time-dependent and neutron-spectrum-dependent minor actinide and Pu concentrations and detailed radial fission power profile calculations for a typical fast reactor (LMFBR) neutron spectrum and the hardened neturon spectrum test region in the ATR. The MCWO-calculated results indicate that the cadmium basket used in the advanced fuel test assembly in the ATR can effectively depress the linear heat generation rate in the experimental fuels and harden the neutron spectrum in the test region.

G. S. Chang; R. G. Ambrosek

2004-05-01T23:59:59.000Z

286

THE SPECTRUM OF Fe II  

SciTech Connect

The spectrum of singly ionized iron (Fe II) has been recorded using high-resolution Fourier transform (FT) and grating spectroscopy over the wavelength range 900 A to 5.5 {mu}m. The spectra were observed in high-current continuous and pulsed hollow cathode discharges using FT spectrometers at the Kitt Peak National Observatory, Tucson, AZ and Imperial College, London and with the 10.7 m Normal Incidence Spectrograph at the National Institute of Standards and Technology. Roughly 12,900 lines were classified using 1027 energy levels of Fe II that were optimized to measured wavenumbers. The wavenumber uncertainties of lines in the FT spectra range from 10{sup -4} cm{sup -1} for strong lines around 4 {mu}m to 0.05 cm{sup -1} for weaker lines around 1500 A. The wavelength uncertainty of lines in the grating spectra is 0.005 A. The ionization energy of (130,655.4 {+-} 0.4) cm{sup -1} was estimated from the 3d{sup 6}({sup 5}D)5g and 3d{sup 6}({sup 5}D)6h levels.

Nave, Gillian [National Institute of Standards and Technology, Gaithersburg, MD 20899-8422 (United States); Johansson, Sveneric, E-mail: gillian.nave@nist.gov [Lund Observatory, University of Lund, Box 43, SE-22100 Lund (Sweden)

2013-01-15T23:59:59.000Z

287

PowerPoint Presentation  

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

Crone, Director Crone, Director Research Reactors Division Oak Ridge National Laboratory UT-Battelle, LLC September 20, 2012 - Bethesda, MD High Flux Isotope Reactor Spallation Neutron Source Oak Ridge National Laboratory - Main Campus Materials Irradiation Testing * Fusion Energy - provides best available neutron spectrum for radiation damage testing on fusion components; collaboration between U.S. and Japan for over thirty years * Fission Energy - research supporting next-generation commercial power reactors including accident tolerant fuel and reactor materials * National Security - Neutron Activation Analysis supporting IAEA non-proliferation monitoring 1,021 Materials and NAA Irradiations in FY2011 Reliable Source of Unique Isotopes * Californium-252 - HFIR supplies 80% of the world

288

Wavelet Spectrum Analysis and Ocean Wind Waves  

E-Print Network (OSTI)

Wavelet Spectrum Analysis and Ocean Wind Waves Paul C. Liu Abstract. Wavelet spectrum analysis is applied to a set of measured ocean wind waves data collected during the 1990 SWADE {Surface Wave Dynamics Experi- ment) program. The results reveal significantly new and previously unexplored Insights on wave

289

Weak Lensing: Dark Matter, Dark Energy  

SciTech Connect

The light rays from distant galaxies are deflected by massive structures along the line of sight, causing the galaxy images to be distorted. Measurements of these distortions, known as weak lensing, provide a way of measuring the distribution of dark matter as well as the spatial geometry of the universe. I will describe the ideas underlying this approach to cosmology. With planned large imaging surveys, weak lensing is a powerful probe of dark energy. I will discuss the observational challenges ahead and recent progress in developing multiple, complementary approaches to lensing measurements.

Jain, Bhuvnesh (University of Pennsylvania) [University of Pennsylvania

2006-02-27T23:59:59.000Z

290

Fast Spectrum Molten Salt Reactor Options  

SciTech Connect

During 2010, fast-spectrum molten-salt reactors (FS-MSRs) were selected as a transformational reactor concept for light-water reactor (LWR)-derived heavy actinide disposition by the Department of Energy-Nuclear Energy Advanced Reactor Concepts (ARC) program and were the subject of a preliminary scoping investigation. Much of the reactor description information presented in this report derives from the preliminary studies performed for the ARC project. This report, however, has a somewhat broader scope-providing a conceptual overview of the characteristics and design options for FS-MSRs. It does not present in-depth evaluation of any FS-MSR particular characteristic, but instead provides an overview of all of the major reactor system technologies and characteristics, including the technology developments since the end of major molten salt reactor (MSR) development efforts in the 1970s. This report first presents a historical overview of the FS-MSR technology and describes the innovative characteristics of an FS-MSR. Next, it provides an overview of possible reactor configurations. The following design features/options and performance considerations are described including: (1) reactor salt options-both chloride and fluoride salts; (2) the impact of changing the carrier salt and actinide concentration on conversion ratio; (3) the conversion ratio; (4) an overview of the fuel salt chemical processing; (5) potential power cycles and hydrogen production options; and (6) overview of the performance characteristics of FS-MSRs, including general comparative metrics with LWRs. The conceptual-level evaluation includes resource sustainability, proliferation resistance, economics, and safety. The report concludes with a description of the work necessary to begin more detailed evaluation of FS-MSRs as a realistic reactor and fuel cycle option.

Gehin, Jess C [ORNL; Holcomb, David Eugene [ORNL; Flanagan, George F [ORNL; Patton, Bruce W [ORNL; Howard, Rob L [ORNL; Harrison, Thomas J [ORNL

2011-07-01T23:59:59.000Z

291

Non-relativistic effective theory of dark matter direct detection  

E-Print Network (OSTI)

Dark matter direct detection searches for signals coming from dark matter scattering against nuclei at a very low recoil energy scale ~ 10 keV. In this paper, a simple non-relativistic effective theory is constructed to describe interactions between dark matter and nuclei without referring to any underlying high energy models. It contains the minimal set of operators that will be tested by direct detection. The effective theory approach highlights the set of distinguishable recoil spectra that could arise from different theoretical models. If dark matter is discovered in the near future in direct detection experiments, a measurement of the shape of the recoil spectrum will provide valuable information on the underlying dynamics. We bound the coefficients of the operators in our non-relativistic effective theory by the null results of current dark matter direct detection experiments. We also discuss the mapping between the non-relativistic effective theory and field theory models or operators, including aspects of the matching of quark and gluon operators to nuclear form factors.

JiJi Fan; Matthew Reece; Lian-Tao Wang

2010-12-10T23:59:59.000Z

292

Non-relativistic effective theory of dark matter direct detection  

SciTech Connect

Dark matter direct detection searches for signals coming from dark matter scattering against nuclei at a very low recoil energy scale ? 10 keV. In this paper, a simple non-relativistic effective theory is constructed to describe interactions between dark matter and nuclei without referring to any underlying high energy models. It contains the minimal set of operators that will be tested by direct detection. The effective theory approach highlights the set of distinguishable recoil spectra that could arise from different theoretical models. If dark matter is discovered in the near future in direct detection experiments, a measurement of the shape of the recoil spectrum will provide valuable information on the underlying dynamics. We bound the coefficients of the operators in our non-relativistic effective theory by the null results of current dark matter direct detection experiments. We also discuss the mapping between the non-relativistic effective theory and field theory models or operators, including aspects of the matching of quark and gluon operators to nuclear form factors.

Fan, JiJi; Wang, Lian-Tao [Department of Physics, Princeton University, Princeton, NJ, 08540 (United States); Reece, Matthew, E-mail: jijifan@princeton.edu, E-mail: mreece@princeton.edu, E-mail: lianwang@princeton.edu [Princeton Center for Theoretical Science, Princeton University, Princeton, NJ, 08540 (United States)

2010-11-01T23:59:59.000Z

293

Spectrum Energy Inc SEI | Open Energy Information  

Open Energy Info (EERE)

Energy Inc SEI Energy Inc SEI Jump to: navigation, search Name Spectrum Energy Inc (SEI) Place Elk Grove, California Zip 95758 Sector Efficiency, Services, Solar Product US-based solar and energy services company that installs PV systems on a turnkey-basis; also provides evaluations of energy efficiency. References Spectrum Energy Inc (SEI)[1] LinkedIn Connections CrunchBase Profile No CrunchBase profile. Create one now! This article is a stub. You can help OpenEI by expanding it. Spectrum Energy Inc (SEI) is a company located in Elk Grove, California . References ↑ "Spectrum Energy Inc (SEI)" Retrieved from "http://en.openei.org/w/index.php?title=Spectrum_Energy_Inc_SEI&oldid=351613" Categories: Clean Energy Organizations Companies Organizations

294

NREL Spectrum of Clean Energy Innovation (Brochure)  

SciTech Connect

This brochure describes the NREL Spectrum of Clean Energy Innovation, which includes analysis and decision support, fundamental science, market relevant research, systems integration, testing and validation, commercialization and deployment. Through deep technical expertise and an unmatched breadth of capabilities, the National Renewable Energy Laboratory (NREL) leads an integrated approach across the spectrum of renewable energy innovation. From scientific discovery to accelerating market deployment, NREL works in partnership with private industry to drive the transformation of our nation's energy systems. NREL integrates the entire spectrum of innovation, including fundamental science, market relevant research, systems integration, testing and validation, commercialization, and deployment. Our world-class analysis and decision support informs every point on the spectrum. The innovation process at NREL is inter-dependent and iterative. Many scientific breakthroughs begin in our own laboratories, but new ideas and technologies may come to NREL at any point along the innovation spectrum to be validated and refined for commercial use.

Not Available

2011-09-01T23:59:59.000Z

295

Distinct optical properties of relativistically degenerate matter  

SciTech Connect

In this paper, we use the collisional quantum magnetohydrodynamic (CQMHD) model to derive the transverse dielectric function of a relativistically degenerate electron fluid and investigate various optical parameters, such as the complex refractive index, the reflection and absorption coefficients, the skin-depth and optical conductivity. In this model we take into accounts effects of many parameters such as the atomic-number of the constituent ions, the electron exchange, electron diffraction effect and the electron-ion collisions. Study of the optical parameters in the solid-density, the warm-dense-matter, the big-planetary core, and the compact star number-density regimes reveals that there are distinct differences between optical characteristics of the latter and the former cases due to the fundamental effects of the relativistic degeneracy and other quantum mechanisms. It is found that in the relativistic degeneracy plasma regime, such as found in white-dwarfs and neutron star crusts, matter possess a much sharper and well-defined step-like reflection edge beyond the x-ray electromagnetic spectrum, including some part of gamma-ray frequencies. It is also remarked that the magnetic field intensity only significantly affects the plasma reflectivity in the lower number-density regime, rather than the high density limit. Current investigation confirms the profound effect of relativistic degeneracy on optical characteristics of matter and can provide an important plasma diagnostic tool for studying the physical processes within the wide scope of quantum plasma regimes be it the solid-density, inertial-confined, or astrophysical compact stars.

Akbari-Moghanjoughi, M. [Department of Physics, Faculty of Sciences, Azarbaijan Shahid Madani University, Tabriz 51745-406 (Iran, Islamic Republic of); International Centre for Advanced Studies in Physical Sciences and Institute for Theoretical Physics, Ruhr University Bochum, Bochum D-44780 (Germany)

2014-06-15T23:59:59.000Z

296

Closed loop adaptive control of spectrum-producing step using neural networks  

DOE Patents (OSTI)

Characteristics of the plasma in a plasma-based manufacturing process step are monitored directly and in real time by observing the spectrum which it produces. An artificial neural network analyzes the plasma spectrum and generates control signals to control one or more of the process input parameters in response to any deviation of the spectrum beyond a narrow range. In an embodiment, a plasma reaction chamber forms a plasma in response to input parameters such as gas flow, pressure and power. The chamber includes a window through which the electromagnetic spectrum produced by a plasma in the chamber, just above the subject surface, may be viewed. The spectrum is conducted to an optical spectrometer which measures the intensity of the incoming optical spectrum at different wavelengths. The output of optical spectrometer is provided to an analyzer which produces a plurality of error signals, each indicating whether a respective one of the input parameters to the chamber is to be increased or decreased. The microcontroller provides signals to control respective controls, but these lines are intercepted and first added to the error signals, before being provided to the controls for the chamber. The analyzer can include a neural network and an optional spectrum preprocessor to reduce background noise, as well as a comparator which compares the parameter values predicted by the neural network with a set of desired values provided by the microcontroller.

Fu, Chi Yung (San Francisco, CA)

1998-01-01T23:59:59.000Z

297

The energy production rate & the generation spectrum of UHECRs  

E-Print Network (OSTI)

We derive simple analytic expressions for the flux and spectrum of ultra-high energy cosmic-rays (UHECRs) predicted in models where the CRs are protons produced by extra-Galactic sources. For a power-law scaling of the CR production rate with redshift and energy, d\\dot{n} /dE\\propto E^-\\alpha (1+z)^m, our results are accurate at high energy, E>10^18.7 eV, to better than 15%, providing a simple and straightforward method for inferring d\\dot{n}/dE from the observed flux at E. We show that current measurements of the UHECR spectrum, including the latest Auger data, imply E^2d\\dot{n}/dE(z=0)=(0.45\\pm0.15)(\\alpha-1) 10^44 erg Mpc^-3 yr^-1 at E<10^19.5 eV with \\alpha roughly confined to 2\\lesseq\\alpha<2.7. The uncertainty is dominated by the systematic and statistic errors in the experimental determination of individual CR event energy, (\\Delta E/E)_{sys} (\\Delta E/E)_{stat} ~20%. At lower energy, d\\dot{n}/dE is uncertain due to the unknown Galactic contribution. Simple models in which \\alpha\\simeq 2 and the transition from Galactic to extra-Galactic sources takes place at the "ankle", E ~10^19 eV, are consistent with the data. Models in which the transition occurs at lower energies require a high degree of fine tuning and a steep spectrum, \\alpha\\simeq 2.7, which is disfavored by the data. We point out that in the absence of accurate composition measurements, the (all particle) energy spectrum alone cannot be used to infer the detailed spectral shapes of the Galactic and extra-Galactic contributions.

Boaz Katz; Ran Budnik; Eli Waxman

2009-03-18T23:59:59.000Z

298

The Energy Spectrum of Fronts: Time Evolution of Shocks in Burgers‚ Equation  

Science Journals Connector (OSTI)

Andrews and Hoskins used semigeostrophic theory to argue that the energy spectrum of a front should decay like the ?8/3 power of the wavenumber. They note, however, that their inviscid analysis is restricted to the very moment of breaking; that ...

John P. Boyd

1992-01-01T23:59:59.000Z

299

Wind Power  

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

Wind Power As the accompanying map of New Mexico shows, the best wind power generation potential near WIPP is along the Delaware Mountain ridge line of the southern Guadalupe...

300

Distillation by repeated measurements: Continuous spectrum case  

SciTech Connect

Repeated measurements on one part of a bipartite system strongly affect the other part that is not measured, the dynamics of which is regulated by an effective contracted evolution operator. When the spectrum of this operator is discrete, the nonmeasured system is driven into a pure state, irrespective of the initial state, provided that the spectrum satisfies certain conditions. We show here that, even in the case of continuous spectrum, an effective distillation can occur under rather general conditions. We confirm it by applying our formalism to a simple model.

Bellomo, Bruno; Compagno, Giuseppe [CNISM and Dipartimento di Scienze Fisiche ed Astronomiche, Universita di Palermo, via Archirafi 36, IT-90123 Palermo (Italy); Nakazato, Hiromichi [Department of Physics, Waseda University, Tokyo 169-8555 (Japan); Yuasa, Kazuya [Waseda Institute for Advanced Study, Waseda University, Tokyo 169-8050 (Japan)

2010-12-15T23:59:59.000Z

Note: This page contains sample records for the topic "matter power spectrum" 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

Nuclear Matter and Nuclear Dynamics  

E-Print Network (OSTI)

Highlights on the recent research activity, carried out by the Italian Community involved in the "Nuclear Matter and Nuclear Dynamics" field, will be presented.

M Colonna

2009-02-26T23:59:59.000Z

302

Survey on Spectrum Utilization in Europe: Measurements, Analyses and Observations  

E-Print Network (OSTI)

major results and comparisons of radio spectrum utilization measurements that have been carried out and physical aspects that will have to be considered in the future radio spectrum management to assure efficient spectrum utilization. Keywords-cognitive radio, dynamic spectrum access, spectrum utilization

Paris-Sud XI, Université de

303

Cooperation and Learning in Multiuser Opportunistic Spectrum Access  

E-Print Network (OSTI)

for the efficient utilization of the radio frequency spectrum is opportunistic spectrum access (OSA), whereCooperation and Learning in Multiuser Opportunistic Spectrum Access Hua Liu§ , Bhaskar spectrum access net- work where spectrum opportunities are time varying and spatially inhomogeneous

Islam, M. Saif

304

MAP: Multiauctioneer Progressive Auction for Dynamic Spectrum Access  

E-Print Network (OSTI)

to access the licensed spectrum, and dynamic spectrum access (DSA) is one of the fundamental functions of CR solution according to the length of step. Index Terms--Cognitive radio, dynamic spectrum access, auction from scarcity in spectrum resource and inefficiency in spectrum usage. Cognitive radio (CR) or dynamic

Wang, Xinbing

305

Secluded WIMP Dark Matter  

E-Print Network (OSTI)

We consider a generic mechanism via which thermal relic WIMP dark matter may be decoupled from the Standard Model, namely through a combination of WIMP annihilation to metastable mediators with subsequent delayed decay to Standard Model states. We illustrate this with explicit examples of WIMPs connected to the Standard Model by metastable bosons or fermions. In all models, provided the WIMP mass is greater than that of the mediator, it can be secluded from the Standard Model with an extremely small elastic scattering cross-section on nuclei and rate for direct collider production. In contrast, indirect signatures from WIMP annihilation are consistent with a weak scale cross-section and provide potentially observable \\gamma-ray signals. We also point out that \\gamma-ray constraints and flavor physics impose severe restrictions on MeV-scale variants of secluded models, and identify limited classes that pass all the observational constraints.

Maxim Pospelov; Adam Ritz; Mikhail B. Voloshin

2007-11-30T23:59:59.000Z

306

Field Theory of Matter  

Science Journals Connector (OSTI)

A speculative field theory of matter is developed. Simple computational methods are used in a preliminary survey of its consequences. The theory exploits the known properties of leptons by means of a principle of symmetry between electrical and nucleonic charge. There are fundamental fields with spins 0, ½, 1. The spinless field is neutral. Spin ½ and 1 fields can carry both electrical and nucleonic charge. The multiplicity of any nonzero charge is 3. Explicit dynamical mechanisms for the breakdown of unitary symmetry and for the muon-electron mass difference are given. A more general view of lepton properties is proposed. Mass relations for baryon and meson multiplets are derived, together with approximate couplings among the multiplets. The weakness of ? production in ?-N collisions and the suppression of the ???+? decay is explained.

Julian Schwinger

1964-08-10T23:59:59.000Z

307

Decision Analysis of Dynamic Spectrum Access Rules  

SciTech Connect

A current trend in spectrum regulation is to incorporate spectrum sharing through the design of spectrum access rules that support Dynamic Spectrum Access (DSA). This paper develops a decision-theoretic framework for regulators to assess the impacts of different decision rules on both primary and secondary operators. We analyze access rules based on sensing and exclusion areas, which in practice can be enforced through geolocation databases. Our results show that receiver-only sensing provides insufficient protection for primary and co-existing secondary users and overall low social welfare. On the other hand, using sensing information between the transmitter and receiver of a communication link, provides dramatic increases in system performance. The performance of using these link end points is relatively close to that of using many cooperative sensing nodes associated to the same access point and large link exclusion areas. These results are useful to regulators and network developers in understanding in developing rules for future DSA regulation.

Juan D. Deaton; Luiz A. DaSilva; Christian Wernz

2011-12-01T23:59:59.000Z

308

ACTION SPECTRUM OF THE "SECOND EMERSON EFFECT"  

E-Print Network (OSTI)

at 670 mju in the action spectrum of the "second Emerson effect"' (22, 33), in the green alga Chlorella the fraction of total absorbed light absorbed by the accessory pigments (be it chlorophyll b in Chlorella

Govindjee

309

Nuclear Power’s Benefits  

Science Journals Connector (OSTI)

Nuclear Power’s Benefits ... Using nuclear power in place of fossil-fuel energy sources, such as coal, has prevented some 1.8 million air-pollution-related deaths and 64 gigatons of carbon emissions globally over the past four decades, a study concludes. ... These estimates suggest policymakers should continue to rely on and expand nuclear power in place of fossil fuels to mitigate climate change, the authors say (Environ. ...

MARK SCHROPE

2013-04-08T23:59:59.000Z

310

Mass Spectrum, Actons and Cosmological Landscape  

E-Print Network (OSTI)

It is suggested that the properties of the mass spectrum of elementary particles could be related with cosmology. Solutions of the Klein-Gordon equation on the Friedmann type manifold with the finite action are constructed. These solutions (actons) have a discrete mass spectrum. We suggest that such solutions could select a universe from cosmological landscape. In particular the solutions with the finite action on de Sitter space are investigated.

V. V. Kozlov; I. V. Volovich

2006-12-13T23:59:59.000Z

311

Critical spectrum of fluctuations for deconfinement at proto-neutron star cores  

E-Print Network (OSTI)

We study the deconfinement of hadronic matter into quark matter in a protoneutron star focusing on the effects of the finite size on the formation of just-deconfined color superconducting quark droplets embedded in the hadronic environment. The hadronic phase is modeled by the non-linear Walecka model at finite temperature including the baryon octet and neutrino trapping. For quark matter we use an $SU(3)_f$ Nambu-Jona-Lasinio model including color superconductivity. The finite size effects on the just deconfined droplets are considered in the frame of the multiple reflection expansion. In addition, we consider that just deconfined quark matter is transitorily out of equilibrium respect to weak interaction, and we impose color neutrality and flavor conservation during the transition. We calculate self-consistently the surface tension and curvature energy density of the quark hadron inter-phase and find that it is larger than the values typically assumed in the literature. The transition density is calculated for drops of different sizes, and at different temperatures and neutrino trapping conditions. Then, we show that energy-density fluctuations are much more relevant for deconfinement than temperature and neutrino density fluctuations. We calculate the critical size spectrum of energy-density fluctuations that allows deconfinement as well as the nucleation rate of each critical bubble. We find that drops with any radii smaller than 800 fm can be formed at a huge rate when matter achieves the bulk transition limit of 5-6 times the nuclear saturation density.

G. Lugones; A. G. Grunfeld

2011-05-19T23:59:59.000Z

312

Fitting the Fermi-LAT GeV excess: on the importance of the propagation of electrons from dark matter  

E-Print Network (OSTI)

An excess of gamma rays at GeV energies has been detected in the Fermi-LAT data. This signal comes from a narrow region around the Galactic Center and has been interpreted as possible evidence for light (30 GeV) dark matter particles. Focussing on the prompt gamma-ray emission, previous works found that the best fit to the data corresponds to annihilations proceeding into b quarks, with a dark matter profile going as r^{-1.2}. We show that this is not the only possible annihilation set-up. More specifically, we show how including the contributions to the gamma-ray spectrum from inverse Compton scattering and bremsstrahlung from electrons produced in dark matter annihilations, and undergoing diffusion through the Galactic magnetic field, significantly affects the spectrum for leptonic final states. This drastically changes the interpretation of the excess in terms of dark matter.

Lacroix, Thomas

2015-01-01T23:59:59.000Z

313

dark matter dark energy inflation  

E-Print Network (OSTI)

theory dark matter dark energy inflation The National Science Foundation The Kavli Foundation NSF Site Review November 28-29, 2005 #12;dark matter dark energy inflation NSF Site Visit ­ November 28 - 29, 2005The National Science Foundation The Kavli Foundation The Theoretical Web UHE cosmic rays B

Hu, Wayne

314

Organic matter in ancient meteorites  

Science Journals Connector (OSTI)

......asteroids. 3: Organic matter in...lead to the production of hydroxy...useful in cell membranes...a part in cell membranes...meteorite organic matter because...form the solar system bequeathed...the early solar system and organic-inorganic......

Mark A Sephton

2004-04-01T23:59:59.000Z

315

Energy Matters in Washington State  

E-Print Network (OSTI)

Energy Matters in Washington State Energy Matters in Washington State www.energy.wsu.edu/library/ November 2009 #12;905 Plum Street SE, Building 3 P.O. Box 43169 Olympia, Washington 98504-3169 Energy University Extension Energy Program. 905 Plum Street SE, Building 3, P.O. Box 43169, Olympia, Washington

Collins, Gary S.

316

A Reconsideration of Matter Waves  

E-Print Network (OSTI)

Matter waves were discovered in the early 20th century from their wavelength, predicted by DeBroglie, Planck's constant divided by the particle's momentum, that is, lmw = h/mv. But, the failure to obtain a reasonable theory for the matter wave frequency resulted somewhat in loss of further interest. It was expected that the frequency of the matter wave should correspond to the particle kinetic energy, that is, fmw = 1/2mv^2/h but the resulting velocity of the matter of the particle, v = fmw x lmw, is that the matter wave moves at one half the speed of the particle, obviously absurd as the particle and its wave must move together. If relativistic mass is used (as it should in any case) the problem remains, the same mass appearing in numerator and denominator and canceling. It is no help to hypothesize that the total energy, not just the kinetic energy, yields the matter wave. That attributes a matter wave to a particle at rest. It also gives the resulting velocity as c^2/v, the wave racing ahead of its particle. A reinterpretation of Einstein's derivation of relativistic kinetic energy (which produced his famous E = mc^2) leads to a valid matter wave frequency and a new understanding of particle kinetics and of the atom's stable orbits.

Roger Ellman

2005-05-16T23:59:59.000Z

317

Energy Gap in Nuclear Matter  

Science Journals Connector (OSTI)

......research-article Articles Energy Gap in Nuclear Matter Takeshi Ishihara a...Research, Kokubunji, Tokyo An energy gap in nuclear matter is studied. The nucleon-nucleon...1966) pp. 1026-1042 Nuclear Force and Energy Gap in Finite Nuclei Hiroharu......

Takeshi Ishihara; Ryozo Tamagaki; Hajime Tanaka; Masaru Yasuno

1963-11-01T23:59:59.000Z

318

Optimal Classifier Based Spectrum Sensing in Cognitive Radio Wireless Systems  

E-Print Network (OSTI)

Optimal Classifier Based Spectrum Sensing in Cognitive Radio Wireless Systems Siddharth Sharma tolerance. General Terms Algorithms, Theory, Reliability. Keywords Cognitive Radio; Cooperative Spectrum Cognitive radio (CR) networks have been proposed as a revolutionary breakthrough to enhance spectrum

Jagannatham, Aditya K.

319

New Constraint on Open Cold-Dark-Matter Models  

E-Print Network (OSTI)

We calculate the large-angle cross-correlation between the cosmic-microwave-background (CMB) temperature and the x-ray-background (XRB) intensity expected in an open Universe with cold dark matter (CDM) and a nearly scale-invariant spectrum of adiabatic density perturbations. Results are presented as a function of the nonrelativistic-matter density $\\Omega_0$ (in units of the critical density) and the x-ray bias $b_x$ (evaluated at a redshift $z\\simeq1$ in evolving-bias models) for both an open Universe and a flat cosmological-constant Universe. Recent experimental upper limits to the amplitude of this cross-correlation provide a new constraint to the $\\Omega_0$-$b_x$ parameter space that open-CDM models (and the open-inflation models that produce them) must satisfy.

Ali Kinkhabwala; Marc Kamionkowski

1999-05-03T23:59:59.000Z

320

Gamma rays from top-mediated dark matter annihilations  

SciTech Connect

Lines in the energy spectrum of gamma rays are a fascinating experimental signal, which are often considered ''smoking gun'' evidence of dark matter annihilation. The current generation of gamma ray observatories are currently closing in on parameter space of great interest in the context of dark matter which is a thermal relic. We consider theories in which the dark matter's primary connection to the Standard Model is via the top quark, realizing strong gamma ray lines consistent with a thermal relic through the forbidden channel mechanism proposed in the Higgs in Space Model. We consider realistic UV-completions of the Higgs in Space and related theories, and show that a rich structure of observable gamma ray lines is consistent with a thermal relic as well as constraints from dark matter searches and the LHC. Particular attention is paid to the one loop contributions to the continuum gamma rays, which can easily swamp the line signals in some cases, and have been largely overlooked in previous literature.

Jackson, C.B. [University of Texas at Arlington, Arlington, TX 76019 (United States); Servant, Géraldine [CERN Physics Department, Theory Division, CH-1211 Geneva 23 (Switzerland); Shaughnessy, Gabe [Department of Physics, University of Wisconsin, Madison, WI 53706 (United States); Tait, Tim M.P. [Department of Physics and Astronomy, University of California, Irvine, CA 92697 (United States); Taoso, Marco, E-mail: geraldine.servant@cern.ch, E-mail: chris@uta.edu, E-mail: gshau@hep.wisc.edu, E-mail: ttait@uci.edu, E-mail: marco.taoso@cea.fr [Institut de Physique Théorique, CEA/Saclay, F-91191 Gif-sur-Yvette Cédex (France)

2013-07-01T23:59:59.000Z

Note: This page contains sample records for the topic "matter power spectrum" 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

High Energy Density Science with High Peak Power Light Sources  

Science Journals Connector (OSTI)

High energy density (HED) science is a growing sub-field of plasma and condensed matter physics. I will examine how recent technological developments in high peak power, petawatt-class...

Ditmire, Todd

322

SciTech Connect: Broad Spectrum Photoelectrochemical Diodes for...  

Office of Scientific and Technical Information (OSTI)

Broad Spectrum Photoelectrochemical Diodes for Solar Hydrogen Generation Citation Details In-Document Search Title: Broad Spectrum Photoelectrochemical Diodes for Solar Hydrogen...

323

Cross-Spectrum of Wind Speed for Meso-Gamma Scales in the Upper Surface Layer over South-Eastern Australia  

Science Journals Connector (OSTI)

Analytical expressions for the cross-spectrum of wind speed are developed for the stochastic simulation of wind power in south-eastern Australia. The expressions...?1.... The influence of site separation distance...

Milton J. Woods; Robert J. Davy; Christopher J. Russell…

2011-10-01T23:59:59.000Z

324

Power Generation and Human Health  

Science Journals Connector (OSTI)

Emissions from power generation are associated with adverse health and ecological effects. Fossil fuel-based power plants (such as coal, oil, and to a lesser extent, natural gas) are associated with emissions of particulate matter (PM), nitrogen oxides (NOx), sulfur dioxide (SO2), and a variety of organic contaminants such as mercury and volatile organic compounds (VOCs). Exposure to emissions from power plants has been associated with a variety of respiratory symptoms, typically based on short-term (e.g., from 5–10 min to 24 h) increases in ambient concentrations. In addition, exposure to constituents from emissions generated by fossil fuels has been associated with increases in premature mortality, particularly in the elderly, and a variety of respiratory and cardiovascular illnesses. Fossil fuels, particularly coal-fired power plants, are responsible for generating the majority of emissions to which humans are exposed.

K. von Stackelberg

2011-01-01T23:59:59.000Z

325

A PER-BASELINE, DELAY-SPECTRUM TECHNIQUE FOR ACCESSING THE 21 cm COSMIC REIONIZATION SIGNATURE  

SciTech Connect

A critical challenge in measuring the power spectrum of 21 cm emission from cosmic reionization is compensating for the frequency dependence of an interferometer's sampling pattern, which can cause smooth-spectrum foregrounds to appear unsmooth and degrade the separation between foregrounds and the target signal. In this paper, we present an approach to foreground removal that explicitly accounts for this frequency dependence. We apply the delay transformation introduced in Parsons and Backer to each baseline of an interferometer to concentrate smooth-spectrum foregrounds within the bounds of the maximum geometric delays physically realizable on that baseline. By focusing on delay modes that correspond to image-domain regions beyond the horizon, we show that it is possible to avoid the bulk of smooth-spectrum foregrounds. We map the point-spread function of delay modes to k-space, showing that delay modes that are uncorrupted by foregrounds also represent samples of the three-dimensional power spectrum, and can be used to constrain cosmic reionization. Because it uses only spectral smoothness to differentiate foregrounds from the targeted 21 cm signature, this per-baseline analysis approach relies on spectrally and spatially smooth instrumental responses for foreground removal. For sufficient levels of instrumental smoothness relative to the brightness of interfering foregrounds, this technique substantially reduces the level of calibration previously thought necessary to detect 21 cm reionization. As a result, this approach places fewer constraints on antenna configuration within an array, and in particular, facilitates the adoption of configurations that are optimized for power-spectrum sensitivity. Under these assumptions, we demonstrate the potential for the Precision Array for Probing the Epoch of Reionization (PAPER) to detect 21 cm reionization at an amplitude of 10 mK{sup 2} near k {approx} 0.2 h Mpc{sup -1} with 132 dipoles in 7 months of observing.

Parsons, Aaron R.; Pober, Jonathan C. [Astronomy Department, University of California, Berkeley, CA (United States); Aguirre, James E.; Moore, David F. [Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA (United States); Carilli, Christopher L. [National Radio Astronomy Observatory, Socorro, NM (United States); Jacobs, Daniel C. [School of Earth and Space Exploration, Arizona State University, Tucson, AZ (United States)

2012-09-10T23:59:59.000Z

326

Imprints of nonthermal Wino dark matter on small-scale structure  

Science Journals Connector (OSTI)

We study how “warm” the Wino dark matter is when it is nonthermally produced by the decays of the gravitino in the early Universe. We clarify the energy distribution of the Wino at the decay of the gravitino and the energy loss process after their production. By solving the Boltzmann equation, we show that a sizable fraction of the Wino dark matter can be warm for the Wino mass mw˜?100–500??GeV. The warmness of the Wino dark matter leaves imprints on the matter power spectra and may provide further insights on the origin of dark matter via the future 21 cm line survey. Our calculations can be applied to other nonthermal Wino production scenarios such as the Wino dark matter produced by the decay of the moduli fields.

Masahiro Ibe; Ayuki Kamada; Shigeki Matsumoto

2013-03-12T23:59:59.000Z

327

Nuclear Power  

Science Journals Connector (OSTI)

Nuclear Power ... THIS WEEK’S issue contains six letters on nuclear power, a representative sample of the letters C&EN received in response to the editorial, “Resist Hysteria,” I wrote shortly after the earthquake and tsunami in Japan devastated the Fukushima Daiichi Nuclear Power Station (C&EN, March 21, page 5). ... Four of the six letters take sharp issue with the primary point I made in the editorial, which was that, despite the severity of the situation in Japan, nuclear power remains an essential component of our overall energy mix for the near to mid-term because it will help us avert the worst impacts of global climate disruption. ...

RUDY M. BAUM

2011-05-09T23:59:59.000Z

328

Power LCAT  

SciTech Connect

POWER LCAT is a software tool used to compare elements of efficiency, cost, and environmental effects between different sources of energy.

Drennen, Thomas

2012-08-15T23:59:59.000Z

329

Yakama Power  

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

Power Administration FROM: J.D. Williams Attorney RE: Initial Comments on Draft Load Following Regional Dialogue Contract Template Dear Mark, Please allow these comments...

330

Power LCAT  

ScienceCinema (OSTI)

POWER LCAT is a software tool used to compare elements of efficiency, cost, and environmental effects between different sources of energy.

Drennen, Thomas

2014-06-27T23:59:59.000Z

331

A Comprehensive Search for Dark Matter Annihilation in Dwarf Galaxies  

E-Print Network (OSTI)

We present a new formalism designed to discover dark matter annihilation occurring in the Milky Way's dwarf galaxies. The statistical framework extracts all available information in the data by simultaneously combining observations of all the dwarf galaxies and incorporating the impact of particle physics properties, the distribution of dark matter in the dwarfs, and the detector response. The method performs maximally powerful frequentist searches and produces confidence limits on particle physics parameters. Probability distributions of test statistics under various hypotheses are constructed exactly, without relying on large sample approximations. The derived limits have proper coverage by construction and claims of detection are not biased by imperfect background modeling. We implement this formalism using data from the Fermi Gamma-ray Space Telescope to search for an annihilation signal in the complete sample of Milky Way dwarfs whose dark matter distributions can be reliably determined. We find that the...

Geringer-Sameth, Alex; Walker, Matthew G

2014-01-01T23:59:59.000Z

332

Power-Law and Long-Memory Characteristics of the Atmospheric General Circulation DMITRY I. VYUSHIN AND PAUL J. KUSHNER  

E-Print Network (OSTI)

Power-Law and Long-Memory Characteristics of the Atmospheric General Circulation DMITRY I. VYUSHIN memory'' or ``power-law'' model. Such a model fits a temporal spectrum to a single power-law function, which thereby accumulates more power at lower frequencies than an AR1 fit. In this study, several power

333

MiniCLEAN Dark Matter Experiment  

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

MiniCLEAN MiniCLEAN Dark Matter Experiment Investigating the field of high energy physics through experiments that strengthen our fundamental understanding of matter, energy,...

334

Reconnection of vortex filaments and Kolmogorov spectrum  

E-Print Network (OSTI)

The energy spectrum of the 3D velocity field, induced by collapsing vortex filaments is studied. One of the aims of this work is to clarify the appearance of the Kolmogorov type energy spectrum $E(k)\\varpropto k^{-5/3}$, observed in many numerical works on discrete vortex tubes (quantized vortex filaments in quantum fluids). Usually, explaining classical turbulent properties of quantum turbulence, the model of vortex bundles, is used. This model is necessary to mimic the vortex stretching, which is responsible for the energy transfer in classical turbulence. In our consideration we do not appeal to the possible "bundle arrangement" but explore alternative idea that the turbulent spectra appear from singular solution, which describe the collapsing line at moments of reconnection. One more aim is related to an important and intensively discussed topic - a role of hydrodynamic collapse in the formation of turbulent spectra. We demonstrated that the specific vortex filament configuration generated the spectrum $E...

Nemirovskii, Sergey K

2014-01-01T23:59:59.000Z

335

Solar Power  

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

Solar Power Solar Power Project Opportunities Abound in the Region The WIPP site is receives abundant solar energy with 6-7 kWh/sq meter power production potential As the accompanying map of New Mexico shows, the WIPP site enjoys abundant year-round sunshine. With an average solar power production potential of 6-7 kWh/sq meter per day, one exciting project being studied for location at WIPP is a 30-50 MW Solar Power Tower: The American Solar Energy Society (ASES) is is a national trade association promoting solar energy as a clean source of electricity, and provides a comprehensive resource for additional information. DOE's Office of Energy Efficiency and Renewable Energy is also a comprehensive resource for more information on renewable energy.

336

Power system  

DOE Patents (OSTI)

A power system includes a prime mover, a transmission, and a fluid coupler having a selectively engageable lockup clutch. The fluid coupler may be drivingly connected between the prime mover and the transmission. Additionally, the power system may include a motor/generator drivingly connected to at least one of the prime mover and the transmission. The power-system may also include power-system controls configured to execute a control method. The control method may include selecting one of a plurality of modes of operation of the power system. Additionally, the control method may include controlling the operating state of the lockup clutch dependent upon the mode of operation selected. The control method may also include controlling the operating state of the motor/generator dependent upon the mode of operation selected.

Hickam, Christopher Dale (Glasford, IL)

2008-03-18T23:59:59.000Z

337

The Late-Time Radio Spectrum of SN1993J  

E-Print Network (OSTI)

We present VLA radio continuum measurements of SN1993J in M81 at the frequencies of 0.32 (P-band), 1.3 and 1.7 (L-band), 4.9 (C-band), 8.5 (X-band), and 14.9 (U-band) GHz carried out on December 17 and 21, 2000, about 2820 days after the supernova explosion. We find that a power-law spectrum, free-free absorbed by an homogeneous, or clumpy, distribution of ionized gas yields the best fit to the radio data. A combined homogeneous-clumpy model is not favored, but neither totally excluded. This result contrasts with the modeling of the early ($t \\lessim $230 days) radio emission from SN1993J, where a mixture of homogeneous and clumpy absorbers appeared to be necessary to adequately describe the behavior of the light curves. The radio spectrum of supernova SN1993J between 0.32 and 14.9 GHz is well characterized by $\\alpha = -0.67 \\pm 0.02 $ ($S_\

M. A. Perez-Torres; A. Alberdi; J. M. Marcaide

2002-05-14T23:59:59.000Z

338

The energy production rate & the generation spectrum of UHECRs  

E-Print Network (OSTI)

We derive simple analytic expressions for the flux and spectrum of ultra-high energy cosmic-rays (UHECRs) predicted in models where the CRs are protons produced by extra-Galactic sources. For a power-law scaling of the CR production rate with redshift and energy, d\\dot{n} /dE\\propto E^-\\alpha (1+z)^m, our results are accurate at high energy, E>10^18.7 eV, to better than 15%, providing a simple and straightforward method for inferring d\\dot{n}/dE from the observed flux at E. We show that current measurements of the UHECR spectrum, including the latest Auger data, imply E^2d\\dot{n}/dE(z=0)=(0.45\\pm0.15)(\\alpha-1) 10^44 erg Mpc^-3 yr^-1 at E<10^19.5 eV with \\alpha roughly confined to 2\\lesseq\\alpha<2.7. The uncertainty is dominated by the systematic and statistic errors in the experimental determination of individual CR event energy, (\\Delta E/E)_{sys}~(\\Delta E/E)_{stat} ~20%. At lower energy, d\\dot{n}/dE is uncertain due to the unknown Galactic contribution. Simple models in which \\alpha\\simeq 2 and the ...

Katz, Boaz; Waxman, Eli

2008-01-01T23:59:59.000Z

339

PowerPoint Presentation  

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

Matter Stephen Nagler Chemical and Engineering Materials Thomas Proffen (Acting) Neutron Data Analysis and Visualization Thomas Proffen Biology and Soft Matter Paul Langan...

340

Analysis of Ocean Electromagnetic Data Using a Hilbert Spectrum Approach  

Science Journals Connector (OSTI)

We apply a newly developed time series analysis technique the Hilbert?Huang Transform (HHT) to naturally occurring ocean electromagnetic data obtained from bottom?mounted sensors. The HHT was originally developed as an alternative to the Fourier power spectral density for the analysis of nonlinear phenomena in water waves. The HHT is applied to the data in two steps. In the first step an empirical mode decomposition is used to extract individual oscillatory modes possessing different characteristic time scales. Unlike Fourier modes however these modes can vary in amplitude and frequency. In the second step the Hilbert transform is used to determine physically meaningful instantaneous frequencies from these modes. We present results showing that the HHT provides a more compact representation of the ocean electromagnetic environment than the Fourier spectrum. In particular the HHT is able to capture nonlinear wave phenomena associated with ocean swell in a single mode without the need for higher order harmonics.

Jeffrey Ridgway; Michael L. Larsen; Cye H. Waldman; Michael Gabbay; Rodney R. Buntzen; C. David Rees

2003-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "matter power spectrum" 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

Hot and Dense QCD Matter  

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

QCD Matter QCD Matter A Community White Paper on the Future of Relativistic Heavy-Ion Physics in the US Unraveling the Mysteries of the Strongly Interacting Quark-Gluon-Plasma Executive Summary This document presents the response of the US relativistic heavy-ion community to the request for comments by the NSAC Subcommittee, chaired by Robert Tribble, that is tasked to recommend optimizations to the US Nuclear Science Program over the next five years. The study of the properties of hot and dense QCD matter is one of the four main areas of nuclear physics research described in the 2007 NSAC Long Range Plan. The US nuclear physics community plays a leading role in this research area and has been instrumental in its most important discovery made over the past decade, namely that hot and dense QCD matter acts as a strongly interacting system with unique and previously unexpected

342

Suprathermal viscosity of dense matter  

SciTech Connect

Motivated by the existence of unstable modes of compact stars that eventually grow large, we study the bulk viscosity of dense matter, taking into account non-linear effects arising in the large amplitude regime, where the deviation {mu}{sub {Delta}} of the chemical potentials from chemical equilibrium fulfills {mu}{sub {Delta}} > or approx. T. We find that this supra-thermal bulk viscosity can provide a potential mechanism for saturating unstable modes in compact stars since the viscosity is strongly enhanced. Our study confirms previous results on strange quark matter and shows that the suprathermal enhancement is even stronger in the case of hadronic matter. We also comment on the competition of different weak channels and the presence of suprathermal effects in various color superconducting phases of dense quark matter.

Alford, Mark; Mahmoodifar, Simin; Schwenzer, Kai [Department of Physics, Washington University in St. Louis, Missouri, 63130 (United States)

2010-12-22T23:59:59.000Z

343

Physical Protection of Classified Matter  

Directives, Delegations, and Requirements

The order establishes policy and objectives for physical protection of classified matter. This directive does not cancel another directive. Chg 1, 7-30-93. Canceled by 5632.1C.

1988-02-03T23:59:59.000Z

344

What's the matter at RHIC?  

E-Print Network (OSTI)

I present here a concise review of the experimental results obtained at the Relativistic Heavy Ion Collider (RHIC), which shed light on the hot and dense quark gluon matter produced at these high temperature and density conditions.

Raphael Granier de Cassagnac

2007-07-03T23:59:59.000Z

345

Comparison of SUSY spectrum calculations and impact on the relic density constraints from WMAP  

E-Print Network (OSTI)

We compare results of four public supersymmetric (SUSY) spectrum codes, Isajet, Softsusy, Spheno and Suspect to estimate the present-day uncertainty in the calculation of the relic density of dark matter in mSUGRA models. We find that even for mass differences of about 1% the spread in the obtained relic densities can be 10%. In difficult regions of the parameter space, such as large tan(beta) or large m_0, discrepancies in the relic density are much larger. We also find important differences in the stau co-annihilation region. We show the impact of these uncertainties on the bounds from WMAP for several scenarios, concentrating on the regions of parameter space most relevant for collider phenomenology. We also discuss the case of non-zero A_0 and the stop co-annihilation region. Moreover, we present a web application for the online comparison of the spectrum codes.

G. Belanger; S. Kraml; A. Pukhov

2005-06-15T23:59:59.000Z

346

1 Spectrum Sharing Games of Network Operators and Cognitive Radios  

E-Print Network (OSTI)

Contents 1 Spectrum Sharing Games of Network Operators and Cognitive Radios Mohammad Hossein advances in radio technology, the spectrum regulators have opened some parts of the available spectrum operators and cognitive radios. Because of the dynamic nature of spectrum sharing, it is difficult

Bencsáth, Boldizsár

347

A Framework for Radio Frequency Spectrum Measurement and Analysis  

E-Print Network (OSTI)

A Framework for Radio Frequency Spectrum Measurement and Analysis V. Rory Petty ITTC-FY2008-TR allocation and the burgeoning problem of spectrum scarcity have prompted an examination of how the radio frequency spectrum is utilized. The radio frequency spectrum is an important national resource that impacts

Kansas, University of

348

Robust Performance of Spectrum Sensing in Cognitive Radio Networks  

E-Print Network (OSTI)

1 Robust Performance of Spectrum Sensing in Cognitive Radio Networks Shimin Gong, Ping Wang) in cognitive radio networks requires SUs to be spectrum aware and know which spectrum bands are occupied by PUs and reduces the system sensitivity on decision variables. Index Terms Cognitive radio network, spectrum

Huang, Jianwei

349

Reputation Aware Collaborative Spectrum Sensing for Mobile Cognitive Radio Networks  

E-Print Network (OSTI)

Reputation Aware Collaborative Spectrum Sensing for Mobile Cognitive Radio Networks Abstract ­ The task of spectrum sensing for Dynamic Spectrum Access in Cognitive Radio Networks (CRNs) is very of Cognitive Radio (CR) operation is the opportunistic utilization of licensed spectrum bands by the Secondary

Zou, Cliff C.

350

Cryptographic Link Signatures for Spectrum Usage Authentication in Cognitive Radio  

E-Print Network (OSTI)

Cryptographic Link Signatures for Spectrum Usage Authentication in Cognitive Radio Xi Tan, Kapil frequency spectrum was inefficiently utilized. To fully use these spectrums, cognitive radio networks have of cognitive radio is to enable the current fixed spectrum channels assigned by Federal Communica- tions

Du, Wenliang "Kevin"

351

Toward Secure Distributed Spectrum Sensing in Cognitive Radio Networks  

E-Print Network (OSTI)

1 Toward Secure Distributed Spectrum Sensing in Cognitive Radio Networks Ruiliang Chen, Jung}@vt.edu Abstract Cognitive radio (CR) is a revolutionary technology that promises to alleviate the spectrum shortage problem and to bring about remarkable improvement in spectrum utilization. Spectrum sensing is one

352

SAMER: Spectrum Aware Mesh Routing in Cognitive Radio Networks  

E-Print Network (OSTI)

SAMER: Spectrum Aware Mesh Routing in Cognitive Radio Networks SHORT PAPER Ioannis Pefkianakis1 in licensed bands, to meet the increasing demand for radio spectrum. The new open spectrum operation--Cognitive Radio, Spectrum Aware Routing I. INTRODUCTION Cognitive radio networks (CORNET) are an emerging multihop

Lu, Songwu

353

Energy-efficient spectrum sensing for cognitive sensor networks  

E-Print Network (OSTI)

spectrum. Traditionally, radio spectrum allocation has been based on exclusive, licensed use of portions for newer wireless net- works and applications. Radio spectrum measurements [13] however indicate that large portions of spectrum licensed to wireless systems remain under-utilized. Consequently there is a growing

Leus, Geert

354

Scheduling Heterogeneous Wireless Systems for Efficient Spectrum Access  

E-Print Network (OSTI)

Radio approach for usage of the Virtual Unlicensed Spectrum (CORVUS) system exploits unoccupied licensed

Bao, Lichun; Liao, Shenghui

2010-01-01T23:59:59.000Z

355

Distributed Routing, Relay Selection, and Spectrum Allocation in Cognitive and  

E-Print Network (OSTI)

of the existing radio spectrum. Based on the reported evidence that static licensed spectrum allocation results--Throughput maximization is a key challenge in cognitive radio ad hoc networks, where the availability of local spectrum radio networks, dynamic spectrum allocation, routing, cross-layer de- sign. I. INTRODUCTION The need

Melodia, Tommaso

356

Federal Spectrum Management at the National Telecommunications and Information Administration  

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

Slides from National Telecommunications and Information Administration's presentation on Federal spectrum management.

357

Shear viscosity of nuclear matter  

E-Print Network (OSTI)

In this talk I report my recent study on the shear viscosity of neutron-rich nuclear matter from a relaxation time approach. An isospin- and momentum-dependent interaction is used in the study. Effects of density, temperature, and isospin asymmetry of nuclear matter on its shear viscosity have been discussed. Similar to the symmetry energy, the symmetry shear viscosity is defined and its density and temperature dependence are studied.

Jun Xu

2013-02-01T23:59:59.000Z

358

Lorentz-violating dark matter  

E-Print Network (OSTI)

LORENTZ-VIOLATING DARK MATTER A Dissertation by ANTONIO R. MONDRAGON Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY May 2007 Major Subject...: Physics LORENTZ-VIOLATING DARK MATTER A Dissertation by ANTONIO R. MONDRAGON Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY Approved by: Chair...

Mondragon, Antonio Richard

2009-05-15T23:59:59.000Z

359

Cosmology, Thermodynamics and Matter Creation  

E-Print Network (OSTI)

Several approaches to the matter creation problem in the context of cosmological models are summarily reviewed. A covariant formulation of the general relativistic imperfect simple fluid endowed with a process of matter creation is presented. By considering the standard big bang model, it is shown how the recent results of Prigogine et alii \\cite{1} can be recovered and, at the same time their limits of validity are explicited.

J. A. S. Lima; M. O. Calvao; I. Waga

2007-08-24T23:59:59.000Z

360

Strathclyde powerS ahead  

E-Print Network (OSTI)

Strathclyde powerS ahead the future of renewable energy SHARING AND ENHANCING RESEARCH Discover the vision of Principal Professor Jim McDonald THE FUTURE OF ENERGY Strathclyde pioneers renewableEdicinE Snapshot the reSearcher Following a decade of environmental research in her native egypt, nabila saleem

Mottram, Nigel

Note: This page contains sample records for the topic "matter power spectrum" 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

Power America  

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

Power America will focus on wide bandgap (WBG) semiconductors - the same materials used in LED light fixtures and many flat screen TVs. The Institute will use $70 million provided by the U.S. Department of Energy's Advanced Manufacturing Office to support and manage its programs over the next five years. This Institute is one of three new innovation hubs announced by President Obama in his 2013 State of the Union address and part of the National Network for Manufacturing Innovation (NNMI). Power America was formerly called the Next Generation Power Electronics National Manufacturing Innovation Institute.

362

A Survey on Dynamic Spectrum Access Techniques for Cognitive Radio  

E-Print Network (OSTI)

Cognitive radio (CR) is a new paradigm that utilizes the available spectrum band. The key characteristic of CR system is to sense the electromagnetic environment to adapt their operation and dynamically vary its radio operating parameters. The technique of dynamically accessing the unused spectrum band is known as Dynamic Spectrum Access (DSA). The dynamic spectrum access technology helps to minimize unused spectrum bands. In this paper, main functions of Cognitive Radio (CR) i.e. spectrum sensing, spectrum management, spectrum mobility and spectrum sharing are discussed. Then DSA models are discussed along with different methods of DSA such as Command and Control, Exclusive-Use, Shared Use of Primary Licensed User and Commons method. Game-theoretic approach using Bertrand game model, Markovian Queuing Model for spectrum allocation in centralized architecture and Fuzzy logic based method are also discussed and result are shown.

Garhwal, Anita

2012-01-01T23:59:59.000Z

363

Methods and apparatuses using filter banks for multi-carrier spread-spectrum signals  

DOE Patents (OSTI)

A transmitter includes a synthesis filter bank to spread a data symbol to a plurality of frequencies by encoding the data symbol on each frequency, apply a common pulse-shaping filter, and apply gains to the frequencies such that a power level of each frequency is less than a noise level of other communication signals within the spectrum. Each frequency is modulated onto a different evenly spaced subcarrier. A demodulator in a receiver converts a radio frequency input to a spread-spectrum signal in a baseband. A matched filter filters the spread-spectrum signal with a common filter having characteristics matched to the synthesis filter bank in the transmitter by filtering each frequency to generate a sequence of narrow pulses. A carrier recovery unit generates control signals responsive to the sequence of narrow pulses suitable for generating a phase-locked loop between the demodulator, the matched filter, and the carrier recovery unit.

Moradi, Hussein; Farhang, Behrouz; Kutsche, Carl A

2014-05-20T23:59:59.000Z

364

Methods and apparatuses using filter banks for multi-carrier spread-spectrum signals  

DOE Patents (OSTI)

A transmitter includes a synthesis filter bank to spread a data symbol to a plurality of frequencies by encoding the data symbol on each frequency, apply a common pulse-shaping filter, and apply gains to the frequencies such that a power level of each frequency is less than a noise level of other communication signals within the spectrum. Each frequency is modulated onto a different evenly spaced subcarrier. A demodulator in a receiver converts a radio frequency input to a spread-spectrum signal in a baseband. A matched filter filters the spread-spectrum signal with a common filter having characteristics matched to the synthesis filter bank in the transmitter by filtering each frequency to generate a sequence of narrow pulses. A carrier recovery unit generates control signals responsive to the sequence of narrow pulses suitable for generating a phase-locked loop between the demodulator, the matched filter, and the carrier recovery unit.

Moradi, Hussein; Farhang, Behrouz; Kutsche, Carl A

2014-10-14T23:59:59.000Z

365

X-ray power density spectra of black hole binaries : a new deadtime model for the RXTE PCA  

E-Print Network (OSTI)

The power density spectrum is an essential tool for determining the frequency content of X-ray radiation from astronomical sources. For neutron star systems, power density spectra reveal coherent oscillations for those ...

Wei, Dennis

2006-01-01T23:59:59.000Z

366

Influence of Dark Matter on Light Propagation in Solar System  

E-Print Network (OSTI)

We investigated the influence of dark matter on light propagation in the solar system. We assumed the spherical symmetry of spacetime and derived the approximate solution of the Einstein equation, which consists of the gravitational attractions caused by the central celestial body, i.e. the Sun, and the dark matter surrounding it. We expressed the dark matter density in the solar system in the following simple power-law form, $\\varrho(t, r) = \\rho(t)(\\ell/r)^k$, where $t$ is the coordinate time; $r$, the radius from the central body; $\\ell$, the normalizing factor; $k$, the exponent characterizing $r$-dependence of dark matter density; and $\\rho(t)$, the arbitrary function of time $t$. On the basis of the derived approximate solution, we focused on light propagation and obtained the additional corrections of the gravitational time delay and the relative frequency shift caused by the dark matter. As an application of our results, we considered the secular increase in the astronomical unit reported by Krasinsky and Brumberg (2004) and found that it was difficult to provide an explanation for the observed $d{\\rm AU}/dt = 15 \\pm 4 ~[{\\rm m/century}]$.

Hideyoshi Arakida

2009-11-17T23:59:59.000Z

367

Economic Viability of Dynamic Spectrum Management  

E-Print Network (OSTI)

and Economics Lab Department of Information Engineering The Chinese University of Hong Kong #12;#12;1 EconomicEconomic Viability of Dynamic Spectrum Management Jianwei Huang Network Communications efficiently. Successful im- plementation of DSM is not a pure engineering issue. It is also a complicated

Huang, Jianwei

368

Energy spectrum of cosmic-ray muons  

Science Journals Connector (OSTI)

The energy spectrum of cosmic-ray muons at sea-level is calculated by the ... in good agreement with the observed data of muons with the zenith angles of 0° and ... the scaling model is valid up to the muon energy

H. Komori; K. Mitsui

369

Spectrum of the Flame of Ethylene  

Science Journals Connector (OSTI)

1 December 1934 research-article Spectrum of the Flame of Ethylene W. M. Vaidya The Royal Society is collaborating with JSTOR to digitize, preserve, and extend access to Proceedings of the Royal Society of London. Series A, Mathematical and Physical Sciences. www.jstor.org

1934-01-01T23:59:59.000Z

370

Microwave Absorption Spectrum of ND3  

Science Journals Connector (OSTI)

The main J=K sequence of inversion lines of the ND3 absorption spectrum were observed and measured between 1589 and 2540 Mc. Quantum numbers up to J, K=18, 18 were assigned by the use of an approximate empirical formula.

R. G. Nuckolls; L. J. Rueger; Harold Lyons

1953-03-01T23:59:59.000Z

371

EARS (Enhancing Access to the Radio Spectrum) PROGRAM: The radio spectrum is a finite but exceedingly valuable natural resource that  

E-Print Network (OSTI)

EARS (Enhancing Access to the Radio Spectrum) PROGRAM: The radio spectrum is a finite communications, among a multitude of others. During the last two decades, the use of the radio spectrum has on the topic of Enhancing Access to the Radio Spectrum. The charge to the workshop was "to identify

Cetiner, Bedri A.

372

Power Projects  

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

Power Projects Power Projects Contact SN Customers Environmental Review-NEPA Operations & Maintenance Planning & Projects Power Marketing Rates You are here: SN Home page > About SNR Power Projects Central Valley: In California's Central Valley, 18 dams create reservoirs that can store 13 million acre-feet of water. The project's 615 miles of canals irrigate an area 400 miles long and 45 miles wide--almost one third of California. Powerplants at the dams have an installed capacity of 2,099 megawatts and provide enough energy for 650,000 people. Transmission lines total about 865 circuit-miles. Washoe: This project in west-central Nevada and east-central California was designed to improve the regulation of runoff from the Truckee and Carson river systems and to provide supplemental irrigation water and drainage, as well as water for municipal, industrial and fishery use. The project's Stampede Powerplant has a maximum capacity of 4 MW.

373

Power Struggle  

Science Journals Connector (OSTI)

Disparate forces such as hydraulic fracturing, or fracking, in the U.S.; the phaseout of nuclear power in Germany; and renewable energy promotion in Europe are conspiring to lessen ... ...

ALEX SCOTT

2013-12-09T23:59:59.000Z

374

Gamma-rays from Dark Matter Annihilation in the Central Region of the Galaxy  

SciTech Connect

In this article, we review the prospects for the FERMI satellite (formerly known as GLAST) to detect gamma-rays from dark matter annihilations in the Central Region of the Milky Way, in light of the recent observations and discoveries of Imaging Atmospheric Cherenkov Telescopes. While the existence of significant astrophysical backgrounds in this part of the sky limits FERMI's discovery potential to some degree, this can be mitigated by exploiting the peculiar energy spectrum and angular distribution of the dark matter annihilation signal relative to those of astrophysical backgrounds.

Serpico, Pasquale Dario; /CERN; Hooper, Dan; /Fermilab /Chicago U., Astron. Astrophys. Ctr.

2009-02-01T23:59:59.000Z

375

PAPER www.rsc.org/pps | Photochemical & Photobiological Sciences Alteration of chromophoric dissolved organic matter by solar UV radiation  

E-Print Network (OSTI)

dissolved organic matter by solar UV radiation causes rapid changes in bacterial community composition dissolved organic carbon concentration. On two occasions during the austral summer, bacteria-free water of the lagoon was exposed to different regions of the solar spectrum (full solar radiation, UV-A + PAR, PAR

Sommaruga, Ruben

376

Double-Disk Dark Matter  

Science Journals Connector (OSTI)

Abstract Based on observational tests of large scale structure and constraints on halo structure, dark matter is generally taken to be cold and essentially collisionless. On the other hand, given the large number of particles and forces in the visible world, a more complex dark sector could be a reasonable or even likely possibility. This hypothesis leads to testable consequences, perhaps portending the discovery of a rich hidden world neighboring our own. We consider a scenario that readily satisfies current bounds that we call Partially Interacting Dark Matter (PIDM). This scenario contains self-interacting dark matter, but it is not the dominant component. Even if PIDM contains only a fraction of the net dark matter density, comparable to the baryonic fraction, the subdominant component’s interactions can lead to interesting and potentially observable consequences. Our primary focus will be the special case of Double-Disk Dark Matter (DDDM), in which self-interactions allow the dark matter to lose enough energy to lead to dynamics similar to those in the baryonic sector. We explore a simple model in which DDDM can cool efficiently and form a disk within galaxies, and we evaluate some of the possible observational signatures. The most prominent signal of such a scenario could be an enhanced indirect detection signature with a distinctive spatial distribution. Even though subdominant, the enhanced density at the center of the galaxy and possibly throughout the plane of the galaxy (depending on precise alignment) can lead to large boost factors, and could even explain a signature as large as the 130 GeV Fermi line. Such scenarios also predict additional dark radiation degrees of freedom that could soon be detectable and would influence the interpretation of future data, such as that from Planck and from the Gaia satellite. We consider this to be the first step toward exploring a rich array of new possibilities for dark matter dynamics.

JiJi Fan; Andrey Katz; Lisa Randall; Matthew Reece

2013-01-01T23:59:59.000Z

377

Viscosity of meson matter  

Science Journals Connector (OSTI)

We report a calculation of the shear viscosity in a relativistic multicomponent meson gas as a function of temperature and chemical potentials. We approximately solve the Uehling-Uhlenbeck transport equation of kinetic theory, appropriate for a boson gas, with relativistic kinematics. Since at low temperatures the gas can be taken as mostly composed of pions, with a fraction of kaons and etas, we explore the region where binary elastic collisions with at least one pion are the dominant scattering processes. Our input meson scattering phase shifts are fits to the experimental data obtained from chiral perturbation theory and the inverse amplitude method. Our results take the correct nonrelativistic limit (viscosity proportional to the square root of the temperature), show a viscosity of the order of the cube of the pion mass up to temperatures somewhat below that mass, and then a large increase due to kaons and etas. Our approximation may break down at even higher temperatures, where the viscosity follows a temperature power law with an exponent near 3.

Antonio Dobado and Felipe J. Llanes-Estrada

2004-06-29T23:59:59.000Z

378

Cosmic neutrino background absorption line in the neutrino spectrum at IceCube  

Science Journals Connector (OSTI)

The IceCube experiment has recently reported a high energy neutrino spectrum between the TeV and PeV scales. The observed neutrino flux can be as a whole well fitted by a simple power law of the neutrino energy E?, E???? (???2). As a notable feature of the spectrum, however, it has a gap between 500 TeV and 1 PeV. Although the existence of the gap in the neutrino spectrum is not statistically significant at this point, it is very enticing to ask whether it might hint at some physics beyond the Standard Model. In this paper, we investigate a possibility that the gap can be interpreted as an absorption line in the power-law spectrum by the cosmic neutrino background through a new resonance in the MeV range. We also show that the absorption line has rich information about not only the MeV scale new particle but also the neutrino masses as well as the distances to the astrophysical sources of the high energy neutrinos. Viable models to achieve this possibility are also discussed.

Masahiro Ibe and Kunio Kaneta

2014-09-24T23:59:59.000Z

379

Cryogenic Dark Matter Search (CDMS): The Hunt for Dark Matter  

SciTech Connect

Deciphering the nature of dark matter has great scientific importance. A leading hypothesis is that dark matter is made of Weakly Interactive Massive Particles (WIMPs), which may result from supersymmetry or additional spatial dimensions. The underground search for elastic scattering of WIMPs on suitable targets (the so-called 'direct detection') is currently led by the Cryogenic Dark Matter Search II (CDMS II) experiment. Its sensitivity is ten times better than any other experiment and we hope to obtain another factor ten in the coming two years. After a brief recall of our recent results, I will describe the complementarity between direct detection experiments, the LHC and the ILC and I will outline the role that SLAC could play in this SuperCDMS program.

Sadoulet, Bernard (UC Berkeley) [UC Berkeley

2006-03-06T23:59:59.000Z

380

Dark matter at DeepCore and IceCube  

Science Journals Connector (OSTI)

With the augmentation of IceCube by DeepCore, the prospect for detecting dark matter annihilation in the Sun is much improved. To complement this experimental development, we provide a thorough template analysis of the particle physics issues that are necessary to precisely interpret the data. Our study is about nitty-gritty and is intended as a framework for detailed work on a variety of dark matter candidates. To accurately predict the source neutrino spectrum, we account for spin-correlations of the final state particles and the helicity-dependence of their decays, and absorption effects at production. We fully treat the propagation of neutrinos through the Sun, including neutrino oscillations, energy losses and tau regeneration. We simulate the survival probability of muons produced in the Earth by using the Muon Monte Carlo program, reproduce the published IceCube effective area, and update the parameters in the differential equation that approximates muon energy losses. To evaluate the zenith-angle dependent atmospheric background event rate, we track the Sun and determine the time it spends at each zenith-angle. Throughout, we employ neutralino dark matter as our example.

V. Barger; Y. Gao; D. Marfatia

2011-03-22T23:59:59.000Z

Note: This page contains sample records for the topic "matter power spectrum" 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.


381

The host galaxies of Compact Steep Spectrum and Gigahertz-Peaked Spectrum radio sources  

E-Print Network (OSTI)

I will review some of the developments in studies of the host galaxy properties of Compact Steep Spectrum (CSS) and GigaHertz-Peaked Spectrum (GPS) radio sources. In contrast to previous reviews structured around observational technique, I will discuss the host galaxy properties in terms of morphology, stellar content and warm gas properties and discuss how compact, young radio-loud AGN are key objects for understanding galaxy evolution.

J. Holt

2008-12-15T23:59:59.000Z

382

Vacuum energy as dark matter  

Science Journals Connector (OSTI)

We consider the vacuum energy of massive quantum fields in an expanding universe. We define a conserved renormalized energy-momentum tensor by means of a comoving cutoff regularization. Using exact solutions for de Sitter space-time, we show that in a certain range of mass and renormalization scales there is a contribution to the vacuum energy density that scales as nonrelativistic matter and that such a contribution becomes dominant at late times. By means of the WKB approximation, we find that these results can be extended to arbitrary Robertson-Walker geometries. We study the range of parameters in which the vacuum energy density would be compatible with current limits on dark matter abundance. Finally, by calculating the vacuum energy in a perturbed Robertson-Walker background, we obtain the speed of sound of density perturbations and show that the vacuum energy density contrast can grow on sub-Hubble scales as in standard cold dark matter scenarios.

F.?D. Albareti; J.?A.?R. Cembranos; A.?L. Maroto

2014-12-05T23:59:59.000Z

383

Energy Gap in Nuclear Matter  

Science Journals Connector (OSTI)

The magnitude of the energy gap in nuclear matter associated with a highly correlated ground state of of the type believed to be important in the theory of superconductivity has been evaluated theoretically. The integral equation of Cooper, Mills, and Sessler is linearized and transformed into a form suitable for numerical solution. The energy gap, calculated by using an appropriate single-particle potential and the Gammel-Thaler two-body potential, is found to be a very strong function of the density of nuclear matter, and of the effective mass at the Fermi surface. It is concluded that the magnitude of the energy gap for nuclear matter should not be compared directly with experimental values for finite nuclei, although the results suggest that if the theory is extended to apply to finite nuclei it probably would be in agreement with experiment.

V. J. Emery and A. M. Sessler

1960-07-01T23:59:59.000Z

384

Chiral condensate in neutron matter  

E-Print Network (OSTI)

A recent chiral perturbation theory calculation of the in-medium quark condensate $$ is extended to the isospin-asymmetric case of pure neutron matter. In contrast to the behavior in isospin-symmetric nuclear matter we find only small deviations from the linear density approximation. This feature originates primarily from the reduced weight factors (e.g. 1/6 for the dominant contributions) of the $2\\pi$-exchange mechanisms in pure neutron matter. Our result suggests therefore that the tendencies for chiral symmetry restoration are actually favored in systems with large neutron excess (e.g. neutron stars). We also analyze the behavior of the density-dependent quark condensate $(\\rho_n)$ in the chiral limit $m_\\pi\\to 0$.

N. Kaiser; W. Weise

2008-08-06T23:59:59.000Z

385

Power inverters  

DOE Patents (OSTI)

Power inverters include a frame and a power module. The frame has a sidewall including an opening and defining a fluid passageway. The power module is coupled to the frame over the opening and includes a substrate, die, and an encasement. The substrate includes a first side, a second side, a center, an outer periphery, and an outer edge, and the first side of the substrate comprises a first outer layer including a metal material. The die are positioned in the substrate center and are coupled to the substrate first side. The encasement is molded over the outer periphery on the substrate first side, the substrate second side, and the substrate outer edge and around the die. The encasement, coupled to the substrate, forms a seal with the metal material. The second side of the substrate is positioned to directly contact a fluid flowing through the fluid passageway.

Miller, David H. (Redondo Beach, CA); Korich, Mark D. (Chino Hills, CA); Smith, Gregory S. (Woodland Hills, CA)

2011-11-15T23:59:59.000Z

386

PROSPECT - A precision oscillation and spectrum experiment  

E-Print Network (OSTI)

Segmented antineutrino detectors placed near a compact research reactor provide an excellent opportunity to probe short-baseline neutrino oscillations and precisely measure the reactor antineutrino spectrum. Close proximity to a reactor combined with minimal overburden yield a high background environment that must be managed through shielding and detector technology. PROSPECT is a new experimental effort to detect reactor antineutrinos from the High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory, managed by UT Battelle for the U.S. Department of Energy. The detector will use novel lithium-loaded liquid scintillator capable of neutron/gamma pulse shape discrimination and neutron capture tagging. These enhancements improve the ability to identify neutrino inverse-beta decays and reject background events in analysis. Results from these efforts will be covered along with their implications for an oscillation search and a precision spectrum measurement.

T. J. Langford

2014-12-22T23:59:59.000Z

387

Energy Spectrum of Buoyancy-driven Turbulence  

E-Print Network (OSTI)

Using direct numerical simulation we demonstrate that stably stratified flows with large Richardson number follow Bolgiano-Obukhov scaling, i.e, the kinetic energy spectrum $E_u(k) \\sim k^{-11/5}$, the entropy spectrum $E_\\theta(k) \\sim k^{-7/5}$, and kinetic energy flux $\\Pi_u(k) \\sim k^{-4/5}$. This is due to the conversion of kinetic energy to potential energy because of buoyancy. We also demonstrate that $E_u(k) \\sim k^{-5/3}$ for stratified flow with weaker buoyancy or smaller Richardson number. We argue that due to the positive energy supply by buoyancy and non-decreasing $\\Pi_u(k)$, Rayleigh B\\'{e}nard convection should follow Kolmogorov-Obukhov scaling ($E_u(k) \\sim k^{-5/3}$).

Verma, Mahendra K; Chatterjee, Anando G

2014-01-01T23:59:59.000Z

388

PROSPECT - A precision oscillation and spectrum experiment  

E-Print Network (OSTI)

Segmented antineutrino detectors placed near a compact research reactor provide an excellent opportunity to probe short-baseline neutrino oscillations and precisely measure the reactor antineutrino spectrum. Close proximity to a reactor combined with minimal overburden yield a high background environment that must be managed through shielding and detector technology. PROSPECT is a new experimental effort to detect reactor antineutrinos from the High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory, managed by UT Battelle for the U.S. Department of Energy. The detector will use novel lithium-loaded liquid scintillator capable of neutron/gamma pulse shape discrimination and neutron capture tagging. These enhancements improve the ability to identify neutrino inverse-beta decays and reject background events in analysis. Results from these efforts will be covered along with their implications for an oscillation search and a precision spectrum measurement.

,

2015-01-01T23:59:59.000Z

389

Matters on a moving brane  

E-Print Network (OSTI)

A novel generalisation of the Dirac-Born-Infeld string scenario is described. It is shown that matter residing on the moving brane is dark and has the so-called disformal coupling to gravity. This gives rise to cosmologies where dark matter stems from the oscillations of the open strings along the brane and the transverse oscillations result in dark energy. Furthermore, due to a new screening mechanism that conceals the fifth force from local experiments, one may even entertain the possibility that the visible sector is also moving along the extra dimensions.

Tomi Sebastian Koivisto; Danielle Elizabeth Wills

2013-12-12T23:59:59.000Z

390

Reconnection of vortex filaments and Kolmogorov spectrum  

E-Print Network (OSTI)

The energy spectrum of the 3D velocity field, induced by collapsing vortex filaments is studied. One of the aims of this work is to clarify the appearance of the Kolmogorov type energy spectrum $E(k)\\varpropto k^{-5/3}$, observed in many numerical works on discrete vortex tubes (quantized vortex filaments in quantum fluids). Usually, explaining classical turbulent properties of quantum turbulence, the model of vortex bundles, is used. This model is necessary to mimic the vortex stretching, which is responsible for the energy transfer in classical turbulence. In our consideration we do not appeal to the possible "bundle arrangement" but explore alternative idea that the turbulent spectra appear from singular solution, which describe the collapsing line at moments of reconnection. One more aim is related to an important and intensively discussed topic - a role of hydrodynamic collapse in the formation of turbulent spectra. We demonstrated that the specific vortex filament configuration generated the spectrum $E(k)$ close to the Kolmogorov dependence and discussed the reason for this as well as the reason for deviation. We also discuss the obtained results from point of view of the both classical and quantum turbulence.

Sergey K. Nemirovskii

2014-04-19T23:59:59.000Z

391

Power Right. Power Smart. Efficient Computer Power Supplies and Monitors. |  

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

Power Right. Power Smart. Efficient Computer Power Supplies and Power Right. Power Smart. Efficient Computer Power Supplies and Monitors. Power Right. Power Smart. Efficient Computer Power Supplies and Monitors. March 10, 2009 - 6:00am Addthis John Lippert Power supplies convert the AC power that you get from your electric company into the DC power consumed by most electronics, including your computer. We expect our power supplies to be safe, reliable, and durable. If they meet those criteria, then they're all alike, except for cost, right? Well, not exactly. You see, there's one other important feature that sets them apart: efficiency. And I don't know about you, but I believe waste is bad. For me, high efficiency is one important feature that's needed for something to be high quality. So isn't it ridiculous that most power

392

Power Right. Power Smart. Efficient Computer Power Supplies and Monitors. |  

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

Power Right. Power Smart. Efficient Computer Power Supplies and Power Right. Power Smart. Efficient Computer Power Supplies and Monitors. Power Right. Power Smart. Efficient Computer Power Supplies and Monitors. March 10, 2009 - 6:00am Addthis John Lippert Power supplies convert the AC power that you get from your electric company into the DC power consumed by most electronics, including your computer. We expect our power supplies to be safe, reliable, and durable. If they meet those criteria, then they're all alike, except for cost, right? Well, not exactly. You see, there's one other important feature that sets them apart: efficiency. And I don't know about you, but I believe waste is bad. For me, high efficiency is one important feature that's needed for something to be high quality. So isn't it ridiculous that most power

393

Power Spectra to 1% Accuracy between Dynamical Dark Energy Cosmologies  

E-Print Network (OSTI)

For dynamical dark energy cosmologies we carry out a series of N-body gravitational simulations, achieving percent level accuracy in the relative mass power spectra at any redshift. Such accuracy in the power spectrum is necessary for next generation cosmological mass probes. Our matching procedure reproduces the CMB distance to last scattering and delivers subpercent level power spectra at z=0 and z~3. We discuss the physical implications for probing dark energy with surveys of large scale structure.

Matthew J. Francis; Geraint F. Lewis; Eric V. Linder

2007-04-03T23:59:59.000Z

394

A Comprehensive Search for Dark Matter Annihilation in Dwarf Galaxies  

E-Print Network (OSTI)

We present a new formalism designed to discover dark matter annihilation occurring in the Milky Way's dwarf galaxies. The statistical framework extracts all available information in the data by simultaneously combining observations of all the dwarf galaxies and incorporating the impact of particle physics properties, the distribution of dark matter in the dwarfs, and the detector response. The method performs maximally powerful frequentist searches and produces confidence limits on particle physics parameters. Probability distributions of test statistics under various hypotheses are constructed exactly, without relying on large sample approximations. The derived limits have proper coverage by construction and claims of detection are not biased by imperfect background modeling. We implement this formalism using data from the Fermi Gamma-ray Space Telescope to search for an annihilation signal in the complete sample of Milky Way dwarfs whose dark matter distributions can be reliably determined. We find that the observed data is consistent with background for each of the dwarf galaxies individually as well as in a joint analysis. The strongest constraints are at small dark matter particle masses. Taking the median of the systematic uncertainty in dwarf density profiles, the cross section upper limits are below the pure s-wave weak scale relic abundance value (2.2 x 10^-26 cm^3/s) for dark matter masses below 26 GeV (for annihilation into b quarks), 29 GeV (tau leptons), 35 GeV (up, down, strange, charm quarks and gluons), 6 GeV (electrons/positrons), and 114 GeV (two-photon final state). For dark matter particle masses less than 1 TeV, these represent the strongest limits obtained to date using dwarf galaxies.

Alex Geringer-Sameth; Savvas M. Koushiappas; Matthew G. Walker

2014-10-08T23:59:59.000Z

395

Star Power  

SciTech Connect

The U.S. Department of Energy's Princeton Plasma Physics Laboratory has released ''Star Power,'' a new informational video that uses dramatic and beautiful images and thought-provoking interviews to highlight the importance of the Laboratory's research into magnetic fusion.

None

2014-10-17T23:59:59.000Z

396

Solar Power  

Science Journals Connector (OSTI)

...of desert solar energy farm with 30 percent conversion...85 percent of the solar farm energy now reflected back...Washington, D.C. 20550. Wind Power Martin Wolf (19...counting the cost of the offshore platforms, would thus...15 billion. If these wind generators were placed...

Paul E. Damon

1974-08-09T23:59:59.000Z

397

Star Power  

ScienceCinema (OSTI)

The U.S. Department of Energy's Princeton Plasma Physics Laboratory has released ''Star Power,'' a new informational video that uses dramatic and beautiful images and thought-provoking interviews to highlight the importance of the Laboratory's research into magnetic fusion.

None

2014-11-18T23:59:59.000Z

398

Power Factor Compensation (PFC) Power Factor Compensation  

E-Print Network (OSTI)

Power Factor Compensation (PFC) Power Factor Compensation The power factor (PF) is defined as the ratio between the active power and the apparent power of a system. If the current and voltage are periodic with period , and [ ), then the active power is defined by ( ) ( ) (their inner product

Knobloch,Jürgen

399

Dressed-state approach to matter-wave mixing of bosons  

SciTech Connect

A dressed-state approach to mixing of bosonic matter waves is presented. Two cases are studied using this formalism. In the first, two macroscopically populated modes of atoms (two-wave mixing) are coupled through the presence of light. In the second case, three modes of Bogoliubov quasiparticles (three-wave mixing) are coupled through s-wave interaction. In both cases, wave mixing induces oscillations in the population of the different modes that decay due to interactions. Analytic expressions for the dressed basis spectrum and the evolution of the mode populations in time are derived both for resonant mixing and nonresonant mixing. Oscillations in the population of a given mode are shown to lead to a splitting in the decay spectrum of that mode, in analogy with the optical Autler-Townes splitting in the decay spectrum of a strongly driven atom. These effects cannot be described by a mean-field approximation.

Rowen, E.; Ozeri, R.; Katz, N.; Pugatch, R.; Davidson, N. [Department of Physics of Complex Systems, Weizmann Institute of Science, Rehovot 76100 (Israel)

2005-11-15T23:59:59.000Z

400

Universal Ownership: Why Environmental Externalities Matter to  

Open Energy Info (EERE)

Universal Ownership: Why Environmental Externalities Matter to Universal Ownership: Why Environmental Externalities Matter to Institutional Investors Jump to: navigation, search Tool Summary Name: Universal Ownership: Why Environmental Externalities Matter to Institutional Investors Agency/Company /Organization: UNEP-Financing Initiative Focus Area: Industry Topics: Co-benefits assessment Resource Type: Lessons learned/best practices Website: www.unepfi.org/fileadmin/documents/universal_ownership.pdf Universal Ownership: Why Environmental Externalities Matter to Institutional Investors Screenshot References: Universal Ownership: Why Environmental Externalities Matter to Institutional Investors[1] Logo: Universal Ownership: Why Environmental Externalities Matter to Institutional Investors Summary "This study assesses the financial implications of unsustainable natural

Note: This page contains sample records for the topic "matter power spectrum" 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

Phi Meson in Dense Matter  

E-Print Network (OSTI)

The effect of the kaon loop correction to the property of a phi meson in dense matter is studied in the vector dominance model. Using the density-dependent kaon effective mass determined from the linear chiral perturbation theory, we find...

Ko, Che Ming; Levai, P.; Qiu, X. J.; Li, C. T.

1992-01-01T23:59:59.000Z

402

Solar Neutrino Matter Effects Redux  

E-Print Network (OSTI)

Following recent low-threshold analysis of the Sudbury Neutrino Observatory and asymmetry measurements of the BOREXINO Collaboration of the solar neutrino flux, we revisit the analysis of the matter effects in the Sun. We show that solar neutrino data constrains the mixing angle $\\theta_{13}$ poorly and that subdominant Standard Model effects can mimic the effects of the physics beyond the Standard Model.

A. B. Balantekin; A. Malkus

2011-12-19T23:59:59.000Z

403

The Information and the Matter  

E-Print Network (OSTI)

In this article a revised, to some extent, version of the Information concept as utmost fundamental essence ("The Information and the Matter",v1) is presented - a little more logical grounds and may be of a philosophy, the correction and the development of the gravity force concept, etc...

S. V. Shevchenko; V. V. Tokarevsky

2007-03-05T23:59:59.000Z

404

1569003080 1 Characterization of Spectrum Activities in the  

E-Print Network (OSTI)

interference, and policy performance with local and cooperative sensing. We analyze the collected data. Jung is with the Electrical and Computer Engineering Department, The University of California, Davis and dynamic spectrum policies, including regulation recommendations, secondary market spectrum leasing rulings

Liu, Xin

405

Centralized Collaborative Compressed Sensing of Wideband Spectrum for Cognitive Radios  

E-Print Network (OSTI)

1 Centralized Collaborative Compressed Sensing of Wideband Spectrum for Cognitive Radios Hessam, spectrum sensing, cognitive radio, distri- bution discontinuities, algebraic detection, wideband. I technique for cognitive radio systems which combines algebraic tools and compressive sampling techniques

Paris-Sud XI, Université de

406

A day in the life of the RF spectrum  

E-Print Network (OSTI)

There is a misguided perception that RF spectrum space is fully allocated and fully used though even a superficial study of actual spectrum usage by measuring local RF energy shows it largely empty of radiation. Traditional ...

Cooley, James E. (James Edward)

2005-01-01T23:59:59.000Z

407

The Cosmological Constant of One-Dimensional Matter Coupled Quantum Gravity is Quantized  

E-Print Network (OSTI)

Coupling any interacting quantum mechanical system to gravity in one dimension requires the cosmological constant to belong to the matter energy spectrum and thus to be quantized, even though the gravity sector is free of any quantum dynamics, while physical states are also confined to the subspace of matter quantum states whose energy coincides with the cosmological constant value. These general facts are illustrated through some simple examples. The physical projector quantization approach readily leads to the correct representation of such systems, whereas other approaches relying on gauge fixing methods are often plagued by Gribov problems in which case the quantization rule is not properly recovered. Whether such a quantization of the cosmological constant as well as the other ensuing consequences in terms of physical states extend to higher dimensional matter-gravity coupled quantum systems is clearly a fascinating open issue.

Govaerts, J

2002-01-01T23:59:59.000Z

408

Power superconducting power transmission cable  

DOE Patents (OSTI)

The present invention is for a compact superconducting power transmission cable operating at distribution level voltages. The superconducting cable is a conductor with a number of tapes assembled into a subconductor. These conductors are then mounted co-planarly in an elongated dielectric to produce a 3-phase cable. The arrangement increases the magnetic field parallel to the tapes thereby reducing ac losses.

Ashworth, Stephen P. (Cambridge, GB)

2003-01-01T23:59:59.000Z

409

Sequential Detection based Cooperative Spectrum Sensing Algorithms in Cognitive Radio  

E-Print Network (OSTI)

Sequential Detection based Cooperative Spectrum Sensing Algorithms in Cognitive Radio Arun considers the problem of Spectrum Sensing in Cognitive Radio Networks. For this we use a recently developed is not experienced by our algorithm. Keywords-Cognitive Radio, Cooperative Spectrum Sensing, Decentralized Sequential

Sharma, Vinod

410

Competitive Interference-aware Spectrum Access in Cognitive Radio Networks  

E-Print Network (OSTI)

Competitive Interference-aware Spectrum Access in Cognitive Radio Networks Jocelyne Elias, Fabio studies the spectrum access problem in cognitive radio networks from a game theoretical perspective. Finally, we provide numerical results of the proposed spectrum access game in several cognitive radio

Boyer, Edmond

411

High Throughput Spectrum-aware Routing for Cognitive Radio Networks  

E-Print Network (OSTI)

High Throughput Spectrum-aware Routing for Cognitive Radio Networks Ashwin Sampath, Lei Yang, Lili, wireless nodes equipped with cognitive radios [11] do not operate on statically as- signed spectrum who own the spectrum, e.g. analog TV broadcast stations. Such flexibility means cognitive radios can

Zhao, Ben Y.

412

Spectrum Leasing via Distributed Cooperation in Cognitive Radio  

E-Print Network (OSTI)

Spectrum Leasing via Distributed Cooperation in Cognitive Radio Igor Stanojev1 , Osvaldo Simeone1 for cognitive radio. I. INTRODUCTION Cognitive radio is a debated new paradigm for efficient spectrum or unlicensed model [1], requires secondary users to first sense the radio environment in search of spectrum

Yener, Aylin

413

Spectrum Leasing via Distributed Cooperation in Cognitive Radio  

E-Print Network (OSTI)

Spectrum Leasing via Distributed Cooperation in Cognitive Radio Igor Stanojev1, Osvaldo Simeone1 for cognitive radio. I. INTRODUCTION Cognitive radio is a debated new paradigm for efficient spectrum or unlicensed model [1], requires secondary users to first sense the radio environment in search of spectrum

Simeone, Osvaldo

414

Censored Truncated Sequential Spectrum Sensing for Cognitive Radio Networks  

E-Print Network (OSTI)

1 Censored Truncated Sequential Spectrum Sensing for Cognitive Radio Networks Sina Maleki Geert Leus Abstract Reliable spectrum sensing is a key functionality of a cognitive radio network. Cooperative spectrum sensing improves the detection reliability of a cognitive radio system but also increases

Leus, Geert

415

Collaborative Spectrum Sensing from Sparse Observations in Cognitive Radio Networks  

E-Print Network (OSTI)

1 Collaborative Spectrum Sensing from Sparse Observations in Cognitive Radio Networks Jia (Jasmine for the implementation of cognitive radio. Collaborative spectrum sensing among the cognitive radio nodes is expected to improve the ability of checking complete spectrum usage. Due to hardware limitations, each cognitive radio

Yin, Wotao

416

Demonstration of Real-time Spectrum Sensing for Cognitive Radio  

E-Print Network (OSTI)

Demonstration of Real-time Spectrum Sensing for Cognitive Radio Zhe Chen, Nan Guo, and Robert C sensing detects the availability of the radio frequency spectrum in a real-time fashion, which is essen Cognitive radio (CR) has been put forward to make effi- cient use of scarce radio frequency spectrum

Qiu, Robert Caiming

417

Two Phase Spectrum Sharing for Frequency-Agile Radio Networks  

E-Print Network (OSTI)

1 Two Phase Spectrum Sharing for Frequency-Agile Radio Networks Zhenhua Feng and Yaling Yang of modern radios. We solve a joint spectrum sharing and end-to-end rate control problems for general technologies (e.g. software defined radio and cognitive radios) enable more flexible spectrum access through

Ha, Dong S.

418

Throughput Enhancing Cooperative Spectrum Sensing Strategies for Cognitive Radios  

E-Print Network (OSTI)

Throughput Enhancing Cooperative Spectrum Sensing Strategies for Cognitive Radios Kyounghwan Lee growth of wireless services continues to accelerate the exhaustion of usable radio spectrum. The radio channels licensed to the primary users. A main chal- lenge in this case is to design a spectrum sensing

Yener, Aylin

419

Quickest Spectrum Detection Using Hidden Markov Model for Cognitive Radio  

E-Print Network (OSTI)

Quickest Spectrum Detection Using Hidden Markov Model for Cognitive Radio Zhe Chen, Zhen Hu, Robert and recognition under the umbrella of cognitive radio. In the procedure of spectrum recognition, a frequency) opened free white space spectrum on November 4, 2008 [1]. Cognitive radio has been put forward as a more

Qiu, Robert Caiming

420

Partial Cooperation for Spectrum Sharing in Cognitive Radio Network  

E-Print Network (OSTI)

Partial Cooperation for Spectrum Sharing in Cognitive Radio Network Lok Man Law1, Fen Hou2, Jianwei that many licensed radio spectrums are heavily under-utilized. Cognitive radio technology can improve spectrum, without affecting the normal communications of the primary licensed users. In cognitive radio

Paris-Sud XI, Université de

Note: This page contains sample records for the topic "matter power spectrum" 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

Partial Cooperation for Spectrum Sharing in Cognitive Radio Network  

E-Print Network (OSTI)

that many licensed radio spectrums are heavily under-utilized. Cognitive radio technology can improve spectrum, without affecting the normal communications of the primary licensed users. In cognitive radioPartial Cooperation for Spectrum Sharing in Cognitive Radio Network Lok Man Law1, Fen Hou2, Jianwei

Huang, Jianwei

422

Competition and bargaining in wireless networks with spectrum leasing  

E-Print Network (OSTI)

which have bought a license, giving them the exclusive right to use a fixed part of the radio spectrum a license which gives it the right to use spectrum, while the MVNO is a Secondary Operator (SO), which leases a fraction of the spectrum licensed to the PO. The SO is assumed to have deployed a new technology

Paris-Sud XI, Université de

423

ICST Transactions Preprint Cooperation Scheme For Distributed Spectrum  

E-Print Network (OSTI)

ICST Transactions Preprint Cooperation Scheme For Distributed Spectrum Sensing In Cognitive Radio, Philadelphia, PA 19122 Abstract Spectrum sensing is an essential phase in cognitive radio networks (CRNs). It enables secondary users (SUs) to access licensed spectrum, which is temporarily not occupied

Wu, Jie

424

Robust Distributed Spectrum Sensing in Cognitive Radio Networks  

E-Print Network (OSTI)

unlicensed radios to operate in licensed spectrum, provided no harmful interference is expe- riencedRobust Distributed Spectrum Sensing in Cognitive Radio Networks Ruiliang Chen, Jung-Min Park {rlchen, jungmin, kgbian}@vt.edu Abstract--Distributed spectrum sensing (DSS) enables a Cog- nitive Radio

425

Cognitive Radio Networks: How much Spectrum Sharing is Optimal?  

E-Print Network (OSTI)

Cognitive Radio Networks: How much Spectrum Sharing is Optimal? Sudhir Srinivasa and Syed Ali Jafar the traditional `divide and set aside' approach to spectrum regulation ensures that the licensed (primary) users periodically monitors the radio spectrum, intelligently detects occupancy in the different frequency bands

Jafar, Syed A.

426

Spread-spectrum Cognitive Networking: Distributed Channelization and Routing  

E-Print Network (OSTI)

Mainstream cognitive radio proposals focus on opportunistic access to the licensed spectrum where the primary. Moreover, in cognitive radio networks with multi-hop communication requirements, spectrum occupancy or secondary users. In this way, the secondary users share the licensed spectrum with the primary users

Melodia, Tommaso

427

On the Characteristics of Spectrum-Agile Communication Networks  

E-Print Network (OSTI)

space" in radio spectrum, varying on frequency, time, and geographic locations. Thus, it is likely and general observations indicate that much of the radio spectrum is not in use for a significant amount on the opportunistic spectrum utilization by users other than the primary licensed ones on a non-interfering or leasing

Liu, Xin

428

Ensuring Trustworthy Spectrum Sensing in Cognitive Radio Networks  

E-Print Network (OSTI)

Ensuring Trustworthy Spectrum Sensing in Cognitive Radio Networks Ruiliang Chen and Jung-Min Park to coexist with incumbent users in licensed spectrum bands without inducing interference to incumbent--Cognitive Radio, Spectrum Sensing, Primary User Emulation Attack, Location Verification. I. INTRODUCTION The need

429

Spectrum Investment with Uncertainty Based on Prospect Theory  

E-Print Network (OSTI)

Spectrum Investment with Uncertainty Based on Prospect Theory Junlin Yu, Man Hon Cheung, and Jianwei Huang Abstract--We study a secondary wireless operator's spectrum investment problem under is uncertain. We formulate such a hybrid spectrum investment problem as a two-stage optimization prob- lem

Huang, Jianwei

430

Nonlinear Energy Transfer in a Narrow Gravity-Wave Spectrum  

Science Journals Connector (OSTI)

...research-article Nonlinear Energy Transfer in a Narrow Gravity-Wave Spectrum J. C...calculation of the rate of energy transfer due to...a narrow gravity wave spectrum according...typical narrow wind wave spectrum on the nonlinear energy transfer are very...

1979-01-01T23:59:59.000Z

431

Nuclear matter to strange matter transition in holographic QCD  

E-Print Network (OSTI)

We construct a simple holographic QCD model to study nuclear matter to strange matter transition. The interaction of dense medium and hadrons is taken care of by imposing the force balancing condition for stable D4/D6/D6 configuration. By considering the intermediate and light flavor branes interacting with baryon vertex homogeneously distributed along R^3 space and requesting the energy minimization, we find that there is a well defined transition density as a function of current quark mass. We also find that as density goes up very high, intermediate (or heavy) and light quarks populate equally as expected from the Pauli principle. In this sense, the effect of the Pauli principle is realized as dynamics of D-branes.

Youngman Kim; Yunseok Seo; Sang-Jin Sin

2009-11-19T23:59:59.000Z

432

Power Search  

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

You are here: Find a Car Home > Power Search You are here: Find a Car Home > Power Search Power Search Expand any feature by selecting its title bar. Choose as many or as few features as you like. Model Year From: 2015 2014 2013 2012 2011 2010 2009 2008 2007 2006 2005 2004 2003 2002 2001 2000 1999 1998 1997 1996 1995 1994 1993 1992 1991 1990 1989 1988 1987 1986 1985 1984 To: 2015 2014 2013 2012 2011 2010 2009 2008 2007 2006 2005 2004 2003 2002 2001 2000 1999 1998 1997 1996 1995 1994 1993 1992 1991 1990 1989 1988 1987 1986 1985 1984 MSRP Under $15,000 $15,000-$20,000 $20,000-$25,000 $25,000-$30,000 $30,000-$35,000 $35,000-$40,000 $40,000-$45,000 $45,000-$50,000 $50,000-$55,000 $55,000-$60,000 $60,000-$65,000 $65,000-$70,000 $70,000-$75,000 $75,000-$80,000 $80,000-$85,000 Over $85,000 - OR - Minimum: Select... $5,000 $6,000 $7,000 $8,000 $9,000 $10,000 $11,000

433

Optical Absorption Spectrum of AgF  

Science Journals Connector (OSTI)

The optical absorption of thin films of silver monofluoride has been investigated in the visible and ultraviolet region of the spectrum at room and low temperatures. Exciton peaks have been observed at 4.63 and 6.34 eV for samples at 4.8 °K. The first exciton peak is considerably lower in energy than might be expected on the basis of the trend set by the other silver halides. This unusually low energy has led us to speculate that the band structure of AgF may be quite different from those of the other silver halides.

Alfred P. Marchetti and G. L. Bottger

1971-04-15T23:59:59.000Z

434

Raman Spectrum of Graphene and Graphene Layers  

Science Journals Connector (OSTI)

Graphene is the two-dimensional building block for carbon allotropes of every other dimensionality. We show that its electronic structure is captured in its Raman spectrum that clearly evolves with the number of layers. The D peak second order changes in shape, width, and position for an increasing number of layers, reflecting the change in the electron bands via a double resonant Raman process. The G peak slightly down-shifts. This allows unambiguous, high-throughput, nondestructive identification of graphene layers, which is critically lacking in this emerging research area.

A. C. Ferrari; J. C. Meyer; V. Scardaci; C. Casiraghi; M. Lazzeri; F. Mauri; S. Piscanec; D. Jiang; K. S. Novoselov; S. Roth; A. K. Geim

2006-10-30T23:59:59.000Z

435

Cold quark matter in compact stars  

SciTech Connect

We used an equation of state for the cold quark matter to the study of properties of quark stars. We also discuss the absolute stability of quark matter and compute the mass-radius relation for self-bound stars.

Franzon, B.; Fogaca, D. A.; Navarra, F. S. [Instituto de Fisica, Universidade de Sao Paulo Rua do Matao, Travessa R, 187, 05508-090 Sao Paulo, SP (Brazil); Horvath, J. E. [Instituto de Astronomia, Geofisica e Ciencias Atmosfericas, Universidade de Sao Paulo, Rua do Matao, 1226, 05508-090, Sao Paulo, SP (Brazil)

2013-03-25T23:59:59.000Z

436

Condensed Matter Theory Center Wednesday, May 18  

E-Print Network (OSTI)

Condensed Matter Theory Center Seminar Wednesday, May 18 11am-12pm 2205 Physics Building Zhengcheng condensed matter physics is based on two theories: symmetry breaking theory for phases and phase transitions

Lathrop, Daniel P.

437

Condensed Matter Theory Center/JQI  

E-Print Network (OSTI)

Joint Condensed Matter Theory Center/JQI Seminar Wednesday, March 21, 11:00-12:30pm 2205 Physics in condensed matter physics. Among the exciting recent developments in this direction are the discoveries

Lathrop, Daniel P.

438

Condensed Matter Theory Center Tuesday, December 13  

E-Print Network (OSTI)

Condensed Matter Theory Center Seminar Tuesday, December 13 11:00am-12:30pm 2205 Physics Building" Abstract: At sufficiently low temperatures, condensed-matter systems tend to develop order. An notable

Lathrop, Daniel P.

439

Pump Systems Matter Mission and Vision | Department of Energy  

Energy Savers (EERE)

issionofPumpSystemsMatter.pdf More Documents & Publications Overview of Pump Systems Matter Hydraulic Institute Member Benefits Course Overview Pump Systems Matter Optimization...

440

MagLab Audio Dictionary: Condensed Matter Science  

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

Condensed Matter Science? Now Playing: What's Condensed Matter Science? Enable Javascript and Flash to stream the Magnet Minute Jim Brooks Associated Links Condensed Matter...

Note: This page contains sample records for the topic "matter power spectrum" 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

Operations & Maintenance Best Practices Guide: Front Matter  

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

Guide describes the front matter of the Operations and Maintenance Best Practices: a Guide to Achieving Operational Efficiency.

442

Power Right. Power Smart. Efficient Computer Power Supplies and...  

Energy Savers (EERE)

lot of the electricity they consume? Higher efficiency power supplies reduce energy consumption, thus cutting your electricity bill. They reduce power consumption, helping your...

443

Condensed Matter Physics & Materials Science Department, Brookhaven  

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

Presetations Presetations Homepage | Contacts "How can we make an isotropic high-temperature superconductor?," Seminar at Condensed Matter Physics Department, (Brookhaven National Laboratory, Upton, NY, November 27 2007). PDF "Enhancement of Jc in thick MOD and BaF2 coatings through the structure improvement " DOE "Superconductivity for Power Systems" Annual Peer Review, (Arlington, VA, August 7-9 2007). PDF "Texture Development in 2-3 μm Thick YBCO Films Synthesized by BaF2 and MOD Processes on Metal RABiTS(tm) " Materials Research Society Spring Meeting, (San Francisco, CA, April 20 2007). PDF "Films and Crystals: Search for the Perfect Structure. ," Seminar at Condensed Matter Physics Department, (Brookhaven National Laboratory, Upton, NY, March 12 2007). PDF

444

Evanescent light-matter Interactions in Atomic Cladding Wave Guides  

E-Print Network (OSTI)

Alkali vapors, and in particular rubidium, are being used extensively in several important fields of research such as slow and stored light non-linear optics3 and quantum computation. Additionally, the technology of alkali vapors plays a major role in realizing myriad industrial applications including for example atomic clocks magentometers8 and optical frequency stabilization. Lately, there is a growing effort towards miniaturizing traditional centimeter-size alkali vapor cells. Owing to the significant reduction in device dimensions, light matter interactions are greatly enhanced, enabling new functionalities due to the low power threshold needed for non-linear interactions. Here, taking advantage of the mature Complimentary Metal-Oxide-Semiconductor (CMOS) compatible platform of silicon photonics, we construct an efficient and flexible platform for tailored light vapor interactions on a chip. Specifically, we demonstrate light matter interactions in an atomic cladding wave guide (ACWG), consisting of CMOS ...

Stern, Liron; Goykhman, Ilya; Levy, Uriel

2012-01-01T23:59:59.000Z

445

Personal Finance Make Your Money Matter  

E-Print Network (OSTI)

Personal Finance Make Your Money Matter Name: Registration number: Department: Year of study of your portfolio. #12;Personal Finance Make Your Money Matter2 Contents Timetable Page 3 Introduction 16 #12;Personal Finance Make Your Money Matter3 Timetable Friday 6.00 pm Introduction

Stevenson, Mark

446

Nonthermal dark matter in mirage mediation  

SciTech Connect

In mirage-mediation models there exists a modulus field whose mass is O(1000) TeV and its late decay may significantly change the standard thermal relic scenario of the dark matter. We study nonthermal production of the dark matter directly from the modulus decay, and find that for some parameter regions nonthermally produced neutralinos can become the dark matter.

Nagai, Minoru; Nakayama, Kazunori [Institute for Cosmic Ray Research, University of Tokyo, Kashiwa 277-8582 (Japan)

2007-12-15T23:59:59.000Z

447

Modeling galactic halos with predominantly quintessential matter  

E-Print Network (OSTI)

This paper discusses a new model for galactic dark matter by combining an anisotropic pressure field corresponding to normal matter and a quintessence dark energy field having a characteristic parameter $\\omega_q$ such that $-1Guzman et al. (2003). Less exceptional forms of quintessence dark energy do not yield the desired stable orbits and are therefore unsuitable for modeling dark matter.

F. Rahaman; Peter K. F. Kuhfittig; K. Chakraborty; M. Kalam; D. Hossain

2011-01-13T23:59:59.000Z

448

3D Imaging Of Wet Granular Matter  

E-Print Network (OSTI)

3D Imaging Of Wet Granular Matter Leonard Goff Advisor: Dr. Wolfgang Losert With Application to Penetrometer Insertion #12;3D Imaging Of Wet Granular Matter Leonard Goff, Advisor: Dr. Wolfgang Losert CoffeeSand Gravel Oops! #12;3D Imaging Of Wet Granular Matter Leonard Goff, Advisor: Dr. Wolfgang Losert

Anlage, Steven

449

Joint Distributed Access Point Selection and Power Allocation in Cognitive Radio Networks  

E-Print Network (OSTI)

of the cognitive radio network (CRN). Most of the current works dealing with spectrum management in the CRN focus) spectrum mobility, rules that require the CUs to leave the channel if licensed users are detected. Many1 Joint Distributed Access Point Selection and Power Allocation in Cognitive Radio Networks Mingyi

Garcia, Alfredo

450

Cold dark matter heats up  

E-Print Network (OSTI)

One of the principal discoveries in modern cosmology is that standard model particles (including baryons, leptons and photons) together comprise only 5% of the mass-energy budget of the Universe. The remaining 95% consists of dark energy and dark matter (DM). Consequently our picture of the universe is known as {\\Lambda}CDM, with {\\Lambda} denoting dark energy and CDM cold dark matter. {\\Lambda}CDM is being challenged by its apparent inability to explain the low density of DM measured at the centre of cosmological systems, ranging from faint dwarf galaxies to massive clusters containing tens of galaxies the size of the Milky Way. But before making conclusions one should carefully include the effect of gas and stars, which were historically seen as merely a passive component during the assembly of galaxies. We now understand that these can in fact significantly alter the DM component, through a coupling based on rapid gravitational potential fluctuations.

Pontzen, Andrew

2014-01-01T23:59:59.000Z

451

Spectrum Management for Cognitive Radio based on Genetics Algorithm  

E-Print Network (OSTI)

Spectrum scarceness is one of the major challenges that the present world is facing. The efficient use of existing licensed spectrum is becoming most critical as growing demand of the radio spectrum. Different researches show that the use of licensed are not utilized inefficiently. It has been also shown that primary user does not use more than 70% of the licensed frequency band most of the time. Many researchers are trying to found the techniques that efficiently utilize the under-utilized licensed spectrum. One of the approaches is the use of "Cognitive Radio". This allows the radio to learn from its environment, changing certain parameters. Based on this knowledge the radio can dynamically exploit the spectrum holes in the licensed band of the spectrum. This paper w i l l focus on the performance of spectrum allocation technique, based on popular meta-heuristics Genetics Algorithm and analyzing the performance of this technique using Mat Lab.

Singh, Santosh Kumar; Pathak, Vibhakar; Roy, Dr Krishna Chandra

2011-01-01T23:59:59.000Z

452

January/February 2000 2000, Elsevier Science Inc., 1040-6190/00/$see front matter PII S1040-6190(99)00102-5 25 Health Effects of  

E-Print Network (OSTI)

on the application of Pennsylvania Power & Light for approval of construction of a new 138/69 kV transmission line1 years, she has lived underneath the present Minooka-Hoffman Power line. In April 1989, her son to the new power line, no matter which part of the house they happen to be in . . . The witness would like PP

Illinois at Chicago, University of

453

Wind power and Wind power and  

E-Print Network (OSTI)

Wind power and the CDM #12; Wind power and the CDM Emerging practices in developing wind power 2005 Jyoti P. Painuly, Niels-Erik Clausen, Jørgen Fenhann, Sami Kamel and Romeo Pacudan #12; WIND POWER AND THE CDM Emerging practices in developing wind power projects for the Clean Development Mechanism Energy

454

IDENTIFYING BREAKS AND CURVATURE IN THE FERMI SPECTRA OF BRIGHT FLAT SPECTRUM RADIO QUASARS  

SciTech Connect

Knowing the site of {gamma}-ray emission in active galactic nucleus jets will do much for our understanding of the physics of the source. In particular, if the emission region is close to the black hole then absorption of {gamma}-rays with photons from the broad-line region could become significant. Such absorption is predicted to produce two specific spectral breaks in the {gamma}-ray spectra of Flat Spectrum Radio Quasars (FSRQs). We test this hypothesis using three years of Fermi observations of nine bright FSRQs. A simple power-law fit to the spectrum of each source can be significantly improved by introducing a break, but the break energies are inconsistent with those predicted by the double-absorber model. In some cases the fit can be further improved by a log-parabola. In addition, by dividing the data from each source into two equal epochs we find that the best description of an object's spectrum often varies between a log-parabola and a broken power law.

Harris, J.; Daniel, M. K.; Chadwick, P. M., E-mail: j.d.harris@durham.ac.uk [Department of Physics, Durham University, South Road, Durham DH1 3LE (United Kingdom)

2012-12-10T23:59:59.000Z

455

Adaptive transmission schemes of cognitive radio for dynamic spectrum access using wavelets and multiwavelets.  

E-Print Network (OSTI)

??Electromagnetic spectrum is a natural resource and at present its use is regulated by fixed spectrum assignment policy. That is, spectrum is assigned to license… (more)

Manju Mathew.

2012-01-01T23:59:59.000Z

456

Dark matter and the LHC  

E-Print Network (OSTI)

An abundance of astrophysical evidence indicates that the bulk of matter in the universe is made up of massive, electrically neutral particles that form the dark matter (DM). While the density of DM has been precisely measured, the identity of the DM particle (or particles) is a complete mystery. In fact, within the laws of physics as we know them (the Standard Model, or SM), none of the particles have the right properties to make up DM. Remarkably, many new physics extensions of the SM -- designed to address theoretical issues with the electroweak symmetry breaking sector -- require the introduction of new particles, some of which are excellent DM candidates. As the LHC era begins, there are high hopes that DM particles, along with their associated new matter states, will be produced in pp collisions. We discuss how LHC experiments, along with other DM searches, may serve to determine the identity of DM particles and elucidate the associated physics. Most of our discussion centers around theories with weak-scale supersymmetry, and allows for several different DM candidate particles.

Howard Baer; Xerxes Tata

2008-05-13T23:59:59.000Z

457

Power Recovery  

E-Print Network (OSTI)

) - 2,870,000 x 0.8 6 W - 3414 = 70 kw (or 900 hp). When recovering power from an expanding gas, consideration should be given to the final gas temperature. This tem;:>f'rature can be estimated by the formula: T 2 Final temperature, oR. Other... with the requirements make generation fqr more useful. Presently a recovery level of around 500 kw (or 657 hp) appears to be the minimum level which will support an in stallation. In order to achieve reasonable effi ciency, quality equipment with good control...

Murray, F.

458

Cooling, Heating, Generating Power, and Recovering Waste Heat with Thermoelectric Systems  

Science Journals Connector (OSTI)

...the vehicle engine is off. Fuel consumption is reduced...target of 10% fuel reduction...possible in diesel-powered...combustion engines such as those...spectrum of fuels, such as...generation, fuel consumption and CO 2 emissions...

Lon E. Bell

2008-09-12T23:59:59.000Z

459

The Broadband Spectrum of Galaxy Clusters  

E-Print Network (OSTI)

We examine whether nonthermal protons energized during a cluster merger are simultaneously responsible for the Coma cluster's diffuse radio flux (via secondary decay) and the departure of its intra-cluster medium (ICM) from a thermal profile via Coulomb collisions between the quasithermal electrons and the hadrons. Rather than approximating the influence of nonthermal proton/thermal electron collisions as extremely rare events which cause an injection of nonthermal, power-law electrons (the `knock-on' approximation), we self-consistently solve (to our knowledge, for the first time) the covariant kinetic equations for the two populations. The electron population resulting from these collisions is out of equilibrium, yet not a power law, and importantly displays a higher bremsstrahlung radiative efficiency than a pure power law. Observations with GLAST will test this model directly.

Brandon Wolfe; Fulvio Melia

2007-12-02T23:59:59.000Z

460

Power transaction issues in deregulated power systems  

E-Print Network (OSTI)

With the introduction of the deregulation in the power industry, it becomes possible to wheel power across the transmission network. Hence, some issues involving the network's physical capability to transfer power and the allocation of the network...

Roycourt, Henrik

2012-06-07T23:59:59.000Z

Note: This page contains sample records for the topic "matter power spectrum" 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

Policy Matters Ohio | Open Energy Information  

Open Energy Info (EERE)

Matters Ohio Matters Ohio Jump to: navigation, search Name Policy Matters Ohio Address 3631 Perkins Avenue - Suite 4C-East Place Cleveland, Ohio Zip 44114 Website http://www.policymattersohio.o References Policy Matters Ohio[1] LinkedIn Connections This article is a stub. You can help OpenEI by expanding it. Policy Matters Ohio is an organization based in Cleveland, Ohio. References ↑ "Policy Matters Ohio" Retrieved from "http://en.openei.org/w/index.php?title=Policy_Matters_Ohio&oldid=367666" Categories: Policy Organizations Clean Energy Organizations Organizations Stubs What links here Related changes Special pages Printable version Permanent link Browse properties 429 Throttled (bot load) Error 429 Throttled (bot load) Throttled (bot load) Guru Meditation:

462

Energy Matters LLC | Open Energy Information  

Open Energy Info (EERE)

Matters LLC Matters LLC Jump to: navigation, search Name Energy Matters LLC Place Santa Rosa, California Zip 95402 Sector Renewable Energy Product Energy Matters specialises in software tools for the renewable energy industries. References Energy Matters LLC[1] Solar-Estimate.org[2] LinkedIn Connections CrunchBase Profile No CrunchBase profile. Create one now! Energy Matters LLC is a company located in Santa Rosa, California . Solarestimate.gif Solar-Estimate.org Energy Matters created the solar estimator, a useful tool to analyze the benefits of a solar or wind system installation in your home or business. The estimator takes into account your region, average utility bills, and the system you are installing, and calculates a 25-year timeline for you to analyze the potential cost savings on energy.

463

Cosmological perturbations in mimetic matter model  

E-Print Network (OSTI)

We investigate the cosmological evolution of mimetic matter model with arbitrary scalar potential. The cosmological reconstruction is explicitly done for different choices of potential. The cases that mimetic matter model shows the evolution as Cold Dark Matter(CDM), wCDM model, dark matter and dark energy with dynamical $Om(z)$ or phantom dark energy with phantom-non-phantom crossing are presented in detail. The cosmological perturbations for such evolution are studied in mimetic matter model. For instance, the evolution behavior of the matter density contrast which is different from usual one, i.e. $\\ddot \\delta + 2 H \\dot \\delta - \\kappa ^2 \\rho \\delta /2 = 0$ is investigated. The possibility of peculiar evolution of $\\delta$ in the model under consideration is shown. Special attention is paid to the behavior of matter density contrast near to future singularity where decay of perturbations may occur much earlier the singularity.

Matsumoto, Jiro; Sushkov, Sergey V

2015-01-01T23:59:59.000Z

464

ELECTROCHEMICAL POWER FOR TRANSPORTATION  

E-Print Network (OSTI)

and Battery-Electric Powered Special Purpose Vehicles, SAELead-Acid Powered Electric Vehicles, Fifth Internationalmeantime, battery-powered electric vehicles can be expected

Cairns, Elton J.

2012-01-01T23:59:59.000Z

465

Southwestern Power Administration  

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

Courses Instructors NERC Continuing Education Power Operations Training Center You'll find the "Power" of learning at Southwestern's Power Operations Training Center (POTC). POTC's...

466

Southwestern Power Administration  

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

Rate Schedules Skip Navigation Links Excess Energy Hydro Peaking Power Hydro Power and Energy Sold to Sam Rayburn Dam Electric Cooperative (Rayburn) Hydro Power and Energy Sold to...

467

2025 Power Marketing Initiative  

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

Power Allocations Rates 2025 Power Marketing Initiative The Loveland Area Projects (LAP) Firm Electric Service (FES) contracts expire September 30, 2024. Western Area Power...

468

Power management system  

DOE Patents (OSTI)

A method of managing power resources for an electrical system of a vehicle may include identifying enabled power sources from among a plurality of power sources in electrical communication with the electrical system and calculating a threshold power value for the enabled power sources. A total power load placed on the electrical system by one or more power consumers may be measured. If the total power load exceeds the threshold power value, then a determination may be made as to whether one or more additional power sources is available from among the plurality of power sources. At least one of the one or more additional power sources may be enabled, if available.

Algrain, Marcelo C. (Peoria, IL); Johnson, Kris W. (Washington, IL); Akasam, Sivaprasad (Peoria, IL); Hoff, Brian D. (East Peoria, IL)

2007-10-02T23:59:59.000Z

469

Symmetry and Dirac points in graphene spectrum  

E-Print Network (OSTI)

Existence and stability of Dirac points in the dispersion relation of operators periodic with respect to the hexagonal lattice is investigated for different sets of additional symmetries. The following symmetries are considered: rotation by $2\\pi/3$ and inversion, rotation by $2\\pi/3$ and horizontal reflection, inversion or reflection with weakly broken rotation symmetry, and the case where no Dirac points arise: rotation by $2\\pi/3$ and vertical reflection. All proofs are based on symmetry considerations and are elementary in nature. In particular, existence of degeneracies in the spectrum is proved by a transplantation argument (which is deduced from the (co)representation of the relevant symmetry group). The conical shape of the dispersion relation is obtained from its invariance under rotation by $2\\pi/3$. Persistence of conical points when the rotation symmetry is weakly broken is proved using a geometric phase in one case and parity of the eigenfunctions in the other.

Gregory Berkolaiko; Andrew Comech

2014-12-28T23:59:59.000Z

470

The Spectrum of AgD  

Science Journals Connector (OSTI)

The spectrum of AgD has been photographed at high dispersion with an Ag arc in an atmosphere of deuterium as a source. Quantum analyses of the 0,0 and 1,1 bands are presented. The value ?e=3.2595 is found for the lower state. Comparing this with the corresponding value for AgH, the ratio BeiBe for the two isotopic molecules is 0.50511, whereas the ratio of the reduced masses, by using Aston's latest values for the masses of the H and D atoms, is 0.50497. Calculation of the corrections to Be for the anharmonic oscillator as given by J. L. Dunham shows them to affect the Be ratio inappreciably.

Philip G. Koontz

1935-07-15T23:59:59.000Z

471

End of the cosmic neutrino energy spectrum  

E-Print Network (OSTI)

There may be a high-energy cutoff of neutrino events in IceCube data. In particular, IceCube does not observe the Standard Model Glashow-resonance events expected at 6.3 PeV. There are also no higher-energy neutrino signatures in the ANITA and Auger experiments. This absence of high-energy neutrino events motivates models with a fundamental restriction on neutrino energies above a few PeV. The simplest scenario to terminate the neutrino spectrum is Lorentz-invariance violating with a limiting neutrino velocity that is smaller than the speed of light. A consequence is that charged pions are stable above four times the maximum neutrino energy and may serve as a cosmic ray primary.

Anchordoqui, L A; Goldberg, H; Learned, J G; Marfatia, D; Pakvasa, S; Paul, T C; Weiler, T J

2014-01-01T23:59:59.000Z

472

Prompt Fission Neutron Spectrum of Pu241  

Science Journals Connector (OSTI)

The energy distribution of prompt neutrons resulting from the thermal-neutron-induced fission of Pu241 is measured. Fast time-of-flight techniques are employed in the neutron energy range 0.3 to 6.0 Mev. Proton recoils in emulsions are utilized for the measurement of neutron energies from 1.6 to 7.0 Mev. The experimentally determined Pu241 fission neutron spectrum is well represented by the Maxwellian distribution, N(E)?E12e-ET, where E is the neutron energy in Mev, N(E) the number of neutrons per unit energy interval, and T=1.335±0.034 Mev. The measured average Pu241 fission neutron energy is 2.002±0.051 Mev.

A. B. Smith; R. K. Sjoblom; J. H. Roberts

1961-09-15T23:59:59.000Z

473

ON THE INJECTION SPECTRUM OF RELATIVISTIC ELECTRONS IN HIGH-REDSHIFT RADIO GALAXIES  

SciTech Connect

We point out that the remarkable linearity of the ultra-steep radio spectra of high-redshift radio galaxies reflects a previously reported general trend for powerful radio galaxies, according to which the spectral curvature is less for sources having steeper spectra (measured near rest-frame 1 GHz). We argue based on existing theoretical and observational evidence that it is premature to conclude that the particle acceleration mechanism in sources having straight, ultra-steep radio spectra gives rise to an ultra-steep injection spectrum of the radiating electrons. In empirical support for this we show that the estimated injection spectral indices available for a representative sample of 35 compact steep spectrum radio sources are not correlated with their rest-frame (intrinsic) rotation measures, which are known to be typically large, indicating a dense environment, as is also the case for high-z radio galaxies.

Gopal-Krishna; Mhaskey, Mukul [National Centre for Radio Astrophysics/TIFR, Pune University Campus, Pune 411007 (India); Mangalam, A., E-mail: krishna@ncra.tifr.res.in, E-mail: wmu3@gmail.com, E-mail: mangalam@iiap.res.in [Indian Institute of Astrophysics, Sarjapur Road, Koramangala 2nd Block, Bangalore 560034 (India)

2012-01-01T23:59:59.000Z

474

High-Energy Cosmic-Ray Muons Under Thick Layers of Matter I. a Method to Solve the Transport Equation  

E-Print Network (OSTI)

An effective analytical method for calculating energy spectra of cosmic-ray muons at large depths of homogeneous media is developed. The method allows to include an arbitrary (decreasing) muon spectrum at the medium boundary and the energy dependence of both discrete (radiative and photonuclear) and continuous (ionization) muon energy losses, with resonable requirements for the high-energy behavior of the initial spectrum and differential cross sections of the muon-matter interactions. (To be published in the Proceedings of the Second NESTOR International Workshop, 19 -- 21 October 1992, Pylos, Greece.)

V. A. Naumov; S. I. Sinegovsky; E. V. Bugaev

1993-01-22T23:59:59.000Z

475

Fact Sheet: U.S. and China Actions Matter for Global Energy Demand, for  

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

Fact Sheet: U.S. and China Actions Matter for Global Energy Demand, Fact Sheet: U.S. and China Actions Matter for Global Energy Demand, for Global Environmental Quality, and for the Challenge of Global Climate Change Fact Sheet: U.S. and China Actions Matter for Global Energy Demand, for Global Environmental Quality, and for the Challenge of Global Climate Change December 5, 2008 - 4:58pm Addthis The U.S. is committed to working together with China to tackle current energy challenges the world faces, including cultivating sufficient investment, the development and deployment of new energy technologies, and addressing greenhouse gas emissions from producing and using energy. Our cooperation spans power generation, efficient buildings, sustainable transportation, emissions-free nuclear power, and clean fossil fuels. The U.S. and China are the world's largest energy consumers and are

476

Fact Sheet: U.S. and China Actions Matter for Global Energy Demand, for  

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

S. and China Actions Matter for Global Energy Demand, S. and China Actions Matter for Global Energy Demand, for Global Environmental Quality, and for the Challenge of Global Climate Change Fact Sheet: U.S. and China Actions Matter for Global Energy Demand, for Global Environmental Quality, and for the Challenge of Global Climate Change December 5, 2008 - 4:58pm Addthis The U.S. is committed to working together with China to tackle current energy challenges the world faces, including cultivating sufficient investment, the development and deployment of new energy technologies, and addressing greenhouse gas emissions from producing and using energy. Our cooperation spans power generation, efficient buildings, sustainable transportation, emissions-free nuclear power, and clean fossil fuels. The U.S. and China are the world's largest energy consumers and are

477

A proof of Scott's correction for Matter Pedro Balodis Matesanz  

E-Print Network (OSTI)

-Fermi theory (TF in the next), distances scale as the 1=3 power of the nuclear average charge Z, i.e, we would) such that E Q R;Z;N := inf 2H; k k=1 h ; HR;Z;N i H #21; M X j=1 E Q (Z j ) + cZ 7=3 M X j=1 Z 1=3 Ã? j #1A proof of Scott's correction for Matter Pedro Balodis Matesanz January 2002 Abstract In this paper

478

Energy loss of relativistic heavy ions in matter B.A. Weaver*, A.J. Westphal  

E-Print Network (OSTI)

Energy loss of relativistic heavy ions in matter B.A. Weaver*, A.J. Westphal Space Sciences.50.Bw Keywords: Energy loss; Stopping power; Heavy ions 1. Introduction The theory of energy loss has.: + 1-510-642-9733; fax: + 1- 510-643-7629. E-mail address: weaver@curium.ssl.berkeley.edu (B.A. Weaver

Leung, Pui-Tak "Peter"

479

On Spectrum Selection Games in Cognitive Radio Ilaria Malanchini, Matteo Cesana, Nicola Gatti  

E-Print Network (OSTI)

On Spectrum Selection Games in Cognitive Radio Networks Ilaria Malanchini, Matteo Cesana, Nicola to evalu- ate spectrum management functionalities in Cognitive Radio Net- works. The spectrum selection environment, consequently exploiting under-utilized spectrum portions. The motivation for cognitive radio

Gatti, Nicola

480

Abstract--Flexible spectrum sharing is widely seen to be important feature for the future  

E-Print Network (OSTI)

systems. Efficient implementation of spectrum sharing requires novel radio resource management (RRM the spectrum sharing with systems using other radio access technologies. The proposed architecture provides. Index Terms -- Beyond 3G systems, flexible spectrum use, radio resource management, spectrum sharing

Note: This page contains sample records for the topic "matter power spectrum" 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

Spectrum Sensing via Universal Source Coding Jithin K. Sreedharan and Vinod Sharma  

E-Print Network (OSTI)

(Cognitive Radios) to identify the primary (licensed) user's spectrum usage via spectrum sensing. Given. These algorithms are motivated from spectrum sensing application in Cognitive Radios. Universal sequential Radios using universal codes is also considered. Keywords- Cognitive Radio, Spectrum Sensing, Sequential

Sharma, Vinod

482

Hot nuclear matter in an extended Brueckner approach  

Science Journals Connector (OSTI)

The properties of cold and hot nuclear matter are studied in the frame of the Brueckner theory, extended to finite temperature. The basic task is the evaluation of the two-hole line diagram using the Paris potential supplemented by the introduction of three-body forces, coming from the exchange of ? and ? mesons. The latter have an important saturating effect, but not sufficient to reach correct saturation. The latter is achieved by a phenomenological treatment. The properties of hot nuclear matter, for temperatures around 10 MeV, are investigated. Particular attention is paid to one-body properties. The density and temperature dependence of many quantities, like the single-particle energy spectrum, the optical potential, the effective mass, the non-locality of the single-particle field, the mean free path, is displayed and analyzed. The relative importance of the temperature dependence of the g-matrix and of phase space is investigated, especially in relation with the imaginary part of the optical potential and the mean free path. The temperature dependence of the effective mass is particularly studied. It is shown that the peak due to the so-called core polarization effect disappears rapidly as the matter is heated. The evaluation of the entropy and of the level density parameter a, which are closely related, is discussed, and the failure of the Hartree-Fock approach to reproduce the value of a correctly is explained. Two-body properties are also investigated. The temperature and density dependence of the two-body correlations are displayed. Particular attention is paid to the temperature dependence of the effective interaction. The latter is exhibited in a simple manner. It is shown that the effective force felt by low-energy nucleons does not change by more than a few percent when the temperature goes from 0 to 10 MeV. For high-energy nucleons, the change may be as large as ten percent.

A. Lejeune; P. Grange; M. Martzolff; J. Cugnon

1986-01-01T23:59:59.000Z

483

Holographic Viscosity of Fundamental Matter  

E-Print Network (OSTI)

A holographic dual of a finite-temperature SU(N_c) gauge theory with a small number of flavours N_f viscosity to entropy ratio in these theories saturates the conjectured universal bound eta/s >= 1/4\\pi. The contribution of the fundamental matter eta_fund is therefore enhanced at strong 't Hooft coupling lambda; for example, eta_fund ~ lambda N_c N_f T^3 in four dimensions. Other transport coefficients are analogously enhanced. These results hold with or without a baryon number chemical potential.

David Mateos; Robert C. Myers; Rowan M. Thomson

2006-10-16T23:59:59.000Z

484

Sterile dark matter and reionization  

E-Print Network (OSTI)

Sterile neutrinos with masses in the keV range can be the dark matter, and their emission from a supernova can explain the observed velocities of pulsars. The sterile neutrino decays could produce the x-ray radiation in the early universe, which could have an important effect on the formation of the first stars. X-rays could ionize gas and could catalyze the production of molecular hydrogen during the ``dark ages''. The increased fraction of molecular hydrogen could facilitate the cooling and collapse of the primordial gas clouds in which the first stars were formed.

Alexander Kusenko

2006-09-13T23:59:59.000Z

485

Neutrino interactions in neutron matter  

E-Print Network (OSTI)

Neutrino flow is the dominant mechanism of energy transfer in the latest stages of supernovae explosions and in compact stars. The Standard Model of particle physics and accelerator data, provide a satisfactory description of neutrino physics in vacuum up to TeV scale. Nevertheless modeling the dynamics of neutrino interaction in the nuclear environment involves severe difficulties. This thesis in mainly aimed at obtaining the weak response of infinite matter, using both the Correlated Basis Function theory and Landau Theory of Fermi liquid to take into account properly nucleon-nucleon hard core potential and long range correlation (quasi-particle, collective modes, ecc.)

Cipollone, Andrea

2012-01-01T23:59:59.000Z

486

Neutrino interactions in neutron matter  

E-Print Network (OSTI)

Neutrino flow is the dominant mechanism of energy transfer in the latest stages of supernovae explosions and in compact stars. The Standard Model of particle physics and accelerator data, provide a satisfactory description of neutrino physics in vacuum up to TeV scale. Nevertheless modeling the dynamics of neutrino interaction in the nuclear environment involves severe difficulties. This thesis in mainly aimed at obtaining the weak response of infinite matter, using both the Correlated Basis Function theory and Landau Theory of Fermi liquid to take into account properly nucleon-nucleon hard core potential and long range correlation (quasi-particle, collective modes, ecc.)

Andrea Cipollone

2012-12-20T23:59:59.000Z

487

Sandia National Laboratories: Z Pulsed Power Facility  

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

Z-Machine Z-Machine About Z Z Research Z News Contact Us Facebook Twitter YouTube Flickr RSS Z-Machine Z Pulsed Power Facility Science serving the nation Created to validate nuclear weapons models, the Z machine is also in the race for viable fusion energy. Z-Machine From Earth's Core to Black Holes Contributing to discovery science by studying matter at conditions found nowhere else on Earth Center of Z About Z Sandia's Z machine is the world's most powerful and efficient laboratory radiation source. It uses high magnetic fields associated with high electrical currents to produce high temperatures, high pressures, and powerful X-rays for research in high energy density science. The Z machine creates conditions found nowhere else on Earth. Z is part of Sandia's Pulsed Power program, which began in the 1960s.

488

Natural Gas Power  

Science Journals Connector (OSTI)

The purpose of a power plant is to generate electric power. Therefore, the key performance metric of an electric power generator is the net thermal efficiency, which is the ratio of the electric power measured...

Raub W. Smith; Dr. S. Can Gülen

2012-01-01T23:59:59.000Z

489

Solar powered desalination system  

E-Print Network (OSTI)

1.18: Largest PV Power Plants……………………………………………………32 TableTable 1.18: Largest PV Power Plants 19 Power (MW) LocationWorld Canada, Sarnia PV power plant Sarnia (Ontario) Italy,

Mateo, Tiffany Alisa

2011-01-0