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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.


1

The Power Spectrum of Matter  

E-Print Network [OSTI]

We calculate the mean power spectrum of galaxies using published power spectra of galaxies and clusters of galaxies. The mean power spectrum has a relatively sharp maximum on scale 120 Mpc (for Hubble constant h=1), followed by an almost exact power-law spectrum of index n = -1.9 toward smaller scales. The power spectrum found from APM 2-D galaxy distribution and from LCRS and IRAS 1.2 Jy surveys is flatter around the maximum. Power spectra of galaxies and matter are similar in shape, we find the bias parameter of galaxies relative to matter 1.3 + - 0.1. We compare the empirical power spectrum of matter with analytical power spectra and show that the primordial power spectrum has a break in amplitude and a spike.

J. Einasto

1998-11-27T23:59:59.000Z

2

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

E-Print Network [OSTI]

We investigate the interpolation of power spectra of matter fluctuations using artificial neural networks (ANNs). We present a new approach to confront small-scale non-linearities in the matter power spectrum. This ...

Agarwal, Shankar

2012-12-31T23:59:59.000Z

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

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

6

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

7

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

8

EFFECTS OF THE NEUTRINO MASS SPLITTING ON THE NONLINEAR MATTER POWER SPECTRUM  

SciTech Connect (OSTI)

We have performed cosmological N-body simulations which include the effect of the masses of the individual neutrino species. The simulations were aimed at studying the effect of different neutrino hierarchies on the matter power spectrum. Compared to the linear theory predictions, we find that nonlinearities enhance the effect of hierarchy on the matter power spectrum at mildly nonlinear scales. The maximum difference between the different hierarchies is about 0.5% for a sum of neutrino masses of 0.1 eV. Albeit this is a small effect, it is potentially measurable from upcoming surveys. In combination with neutrinoless double-{beta} decay experiments, this opens up the possibility of using the sky to determine if neutrinos are Majorana or Dirac fermions.

Wagner, Christian; Verde, Licia; Jimenez, Raul [Institut de Ciencies del Cosmos (ICC), Universitat de Barcelona (IEEC-UB), Marti i Franques 1, E08028 Barcelona (Spain)

2012-06-20T23:59:59.000Z

9

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

10

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

11

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

12

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

13

Atick-Witten Hagedorn Conjecture, near scale-invariant matter and blue-tilted gravity power spectrum  

E-Print Network [OSTI]

We will provide an interesting new mechanism to generate almost scale invariant seed density perturbations with a red spectrum, while keeping the gravitational wave spectrum blue-tilted in a stringy thermal contracting phase at temperatures beyond the Hagedorn temperature. This phase is often referred to as the Hagedorn phase where the free energy has been conjectured by Atick and Witten to grow more slowly than ordinary radiation. The primordial fluctuations are created by the statistical thermal fluctuations determined by the partition function, rather than quantum vacuum driven fluid dynamical fluctuations. In order for our mechanism to work we require a non-singular bouncing cosmology.

Tirthabir Biswas; Tomi Koivisto; Anupam Mazumdar

2014-05-03T23:59:59.000Z

14

Causality and the Power Spectrum  

E-Print Network [OSTI]

We find constraints on the generation of super-causal-horizon energy perturbations from a smooth initial state, under a simple physical scheme. We quantify these constraints by placing the upper limit $\\lambda_c = 3.0 d_H$ on the wavelength at which the power spectrum turns over to $k^4$ behavior. This means that sub-horizon processes can generate significant power on scales further outside the horizon than one might naively expect. The existence of this limit may have important implications for the interpretation of the small scale power spectrum of the Cosmic Microwave Background.

James Robinson; Benjamin D. Wandelt

1995-07-12T23:59:59.000Z

15

Modelling the TSZ power spectrum  

SciTech Connect (OSTI)

The structure formation in university is a hierarchical process. As universe evolves, tiny density fluctuations that existed in the early universe grows under gravitational instability to form massive large scale structures. The galaxy clusters are the massive viralized objects that forms by accreting smaller clumps of mass until they collapse under their self-gravity. As such galaxy clusters are the youngest objects in the universe which makes their abundance as a function of mass and redshift, very sensitive to dark energy. Galaxy clusters can be detected by measuring the richness in optical waveband, by measuring the X-ray flux, and in the microwave sky using Sunyaev-Zel'dovich (SZ) effect. The Sunyaev-Zel'dovich (SZ) effect has long been recognized as a powerful tool for detecting clusters and probing the physics of the intra-cluster medium. Ongoing and future experiments like Atacama Cosmology Telescope, the South Pole Telescope and Planck survey are currently surveying the microwave sky to develop large catalogs of galaxy clusters that are uniformly selected by the SZ flux. However one major systematic uncertainties that cluster abundance is prone to is the connection between the cluster mass and the SZ flux. As shown by several simulation studies, the scatter and bias in the SZ flux-mass relation can be a potential source of systematic error to using clusters as a cosmology probe. In this study they take a semi-analytic approach for modeling the intra-cluster medium in order to predict the tSZ power spectrum. The advantage of this approach is, being analytic, one can vary the parameters describing gas physics and cosmology simultaneously. The model can be calibrated against X-ray observations of massive, low-z clusters, and using the SZ power spectrum which is sourced by high-z lower mass galaxy groups. This approach allows us to include the uncertainty in gas physics, as dictated by the current observational uncertainties, while measuring the cosmological parameters using the SZ power spectrum data. The paper is organized as follows. In section 2, after a brief review of the halo model description of the SZ power spectrum, they discuss their model for intra-cluster medium explaining various parameters describing gas physics. In section 3, they explore a subset of parameter space using the current low-z X-ray data of galaxy clusters and mass and redshift dependence of our intra-cluster medium model. In section 4, they explore the parameter dependence of SZ power spectrum and show the agreement of the model with the current SZ power spectrum data from SPT survey.

Bhattacharya, Suman [Los Alamos National Laboratory; Shaw, Laurie D [YALE; Nagai, Daisuke [YALE

2010-01-01T23:59:59.000Z

16

Power Spectrum of Inflationary Attractors  

E-Print Network [OSTI]

Inflationary attractors predict the spectral index and tensor-to-scalar ratio to take specific values that are consistent with Planck. An example is the universal attractor for models with a generalised non-minimal coupling, leading to Starobinsky inflation. In this paper we demonstrate that it also predicts a specific relation between the amplitude of the power spectrum and the number of e-folds. The length and height of the inflationary plateau are related via the non-minimal coupling: in a wide variety of examples, the observed power normalisation leads to at least 55 flat e-foldings. Prior to this phase, the inflationary predictions vary and can account for the observational indications of power loss at large angular scales.

Benedict J. Broy; Diederik Roest; Alexander Westphal

2015-01-20T23:59:59.000Z

17

Tilting the Primordial Power Spectrum with Bulk Viscosity  

E-Print Network [OSTI]

Within the context of the cold dark matter model, current observations suggest that inflationary models which generate a tilted primordial power spectrum with negligible gravitational waves provide the most promising mechanism for explaining large scale clustering. The general form of the inflationary potential which produces such a spectrum is a hyperbolic function and is interpreted physically as a bulk viscous stress contribution to the energy-momentum of a perfect baryotropic fluid. This is equivalent to expanding the equation of state as a truncated Taylor series. Particle physics models which lead to such a potential are discussed.

James E. Lidsey

1993-12-16T23:59:59.000Z

18

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

19

Bayesian power spectrum analysis of interferometric data  

E-Print Network [OSTI]

We present a Bayesian power spectrum and signal map inference engine which can be adapted to interferometric observations of anisotropies in the cosmic microwave background, 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 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_p log n_p) where n_p measures the ratio of the size of the detector array to the inter-detector spacing, meaning that Gibbs sampling is a viable technique for meeting the data analysis require...

Sutter, P M; Malu, Siddarth

2011-01-01T23:59:59.000Z

20

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

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

Just enough inflation: power spectrum modifications at large scales  

E-Print Network [OSTI]

We show that models of `just enough' inflation, where the slow-roll evolution lasted only $50-60$ e-foldings, feature modifications of the CMB power spectrum at large angular scales. We perform a systematic and model-independent analysis of any possible non-slow-roll background evolution prior to the final stage of slow-roll inflation. We find a high degree of universality since most common backgrounds like fast-roll evolution, matter or radiation-dominance give rise to a power loss at large angular scales and a peak together with an oscillatory behaviour at scales around the value of the Hubble parameter at the beginning of slow-roll inflation. Depending on the value of the equation of state parameter, different pre-inflationary epochs lead instead to an enhancement of power at low-$\\ell$, and so seem disfavoured by recent observational hints for a lack of CMB power at $\\ell\\lesssim 40$. We also comment on the importance of initial conditions and the possibility to have multiple pre-inflationary stages.

Michele Cicoli; Sean Downes; Bhaskar Dutta; Francisco G. Pedro; Alexander Westphal

2014-07-03T23:59:59.000Z

22

E-Print Network 3.0 - anisotropic power spectrum Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

power spectrum Search Powered by Explorit Topic List Advanced Search Sample search results for: anisotropic power spectrum Page: << < 1 2 3 4 5 > >> 1 Random Scattering and...

23

Lyman Alpha Flux Power Spectrum and Its Covariance  

E-Print Network [OSTI]

We analyze the flux power spectrum and its covariance using simulated Lyman alpha forests. We find that pseudo-hydro techniques are good approximations of hydrodynamical simulations at high redshift. However, the pseudo-hydro techniques fail at low redshift because they are insufficient for characterizing some components of the low-redshift intergalactic medium, notably the warm-hot intergalactic medium. Hence, to use the low-redshift Lyman alpha flux power spectrum to constrain cosmology, one would need realistic hydrodynamical simulations. By comparing one-dimensional mass statistics with flux statistics, we show that the nonlinear transform between density and flux quenches the fluctuations so that the flux power spectrum is much less sensitive to cosmological parameters than the one-dimensional mass power spectrum. The covariance of the flux power spectrum is nearly Gaussian. As such, the uncertainties of the underlying mass power spectrum could still be large, even though the flux power spectrum can be precisely determined from a small number of lines of sight.

Hu Zhan; Romeel Dave; Daniel Eisenstein; Neal Katz

2005-08-10T23:59:59.000Z

24

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

2009-02-19T23:59:59.000Z

25

Sequential Bandwidth and Power Auctions for Spectrum Sharing  

E-Print Network [OSTI]

user's power). Although the worst-case efficiency loss can be significant, numerical results1 Sequential Bandwidth and Power Auctions for Spectrum Sharing Junjik Bae, Eyal Beigman, Randall resource (bandwidth or power) among compet- ing transmitters. The resource is assumed to be managed

Kuzmanovic, Aleksandar

26

MEASURING THE JET POWER OF FLAT-SPECTRUM RADIO QUASARS  

SciTech Connect (OSTI)

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

27

Cosmology Constraints from the Weak Lensing Peak Counts and the Power Spectrum in CFHTLenS  

DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

?Lensing peaks have been proposed as a useful statistic, containing cosmological information from non-Gaussianities that is inaccessible from traditional two-point statistics such as the power spectrum or two-point correlation functions. Here we examine constraints on cosmological parameters from weak lensing peak counts, using the publicly available data from the 154 deg2 CFHTLenS survey. We utilize a new suite of ray-tracing N-body simulations on a grid of 91 cosmological models, covering broad ranges of the three parameters ?m, ?8, and w, and replicating the galaxy sky positions, redshifts, and shape noise in the CFHTLenS observations. We then build an emulator that interpolates the power spectrum and the peak counts to an accuracy of ? 5%, and compute the likelihood in the three-dimensional parameter space (?m, ?8, w) from both observables. We find that constraints from peak counts are comparable to those from the power spectrum, and somewhat tighter when different smoothing scales are combined. Neither observable can constrain w without external data. When the power spectrum and peak counts are combined, the area of the error “banana” in the (?m, ?8) plane reduces by a factor of ? two, compared to using the power spectrum alone. For a flat ? cold dark matter model, combining both statistics, we obtain the constraint ?8(?m/0.27)0.63 = 0.85+0.03-0.03.

Liu, Jia [Department of Astronomy and Astrophysics, Columbia University, New York, NY, (United States); May, Morgan [Physics Department, Brookhaven National Laboratory, Upton, NY, (United States); Petri, Andrea [Department of Physics, Columbia University, New York, NY, (United States); Haiman, Zoltan [Department of Astronomy and Astrophysics, Columbia University, New York, NY, (United States); Institute for Strings, Cosmology, and Astroparticle Physics (ISCAP), Columbia University, New York, (United States); Hui, Lam [Department of Physics, Columbia University, New York, NY, (United States); Institute for Strings, Cosmology, and Astroparticle Physics (ISCAP), Columbia University, New York, (United States); Kratochvil, Jan M. [Astrophysics and Cosmology Research Unit, University of KwaZulu-Natal, Westville, Durban, (South Africa)

2015-03-01T23:59:59.000Z

28

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

29

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

30

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

31

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

32

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

33

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

34

Fractal power spectra plotted upside-down Comment on ``Scaling of power spectrum of extinction events  

E-Print Network [OSTI]

Discussion Fractal power spectra plotted upside-down Comment on ``Scaling of power spectrum. Dimri and Pra- kash interpret their results as demonstrating a fractal pattern in the fossil record or not the underlying data are fractal. Similarly, their use of interpolated time series (in their ¢gures 1b,d, 2a,b, 3a

Kirchner, James W.

35

Higher derivatives and power spectrum in effective single field inflation  

E-Print Network [OSTI]

We study next-to-leading corrections to the effective action of the curvature perturbation obtained by integrating out the coupled heavy isocurvature perturbation. These corrections result from including higher order derivative operators, weighted by the mass scale of the heavy physics, in the effective theory expansion. We find that the correction terms are suppressed by the ratio of the Hubble parameter to the heavy mass scale. The corresponding corrections to the power spectrum of the curvature perturbation are presented for a simple illustrative example.

Jinn-Ouk Gong; Min-Seok Seo; Spyros Sypsas

2015-03-10T23:59:59.000Z

36

Cosmic string formation and the power spectrum of field configurations  

E-Print Network [OSTI]

We examine the statistical properties of defects formed by the breaking of a U(1) symmetry when the Higgs field has a power spectrum $P(k) \\propto k^n$. We find a marked dependence of the amount of infinite string on the spectral index $n$ and empirically identify an analytic form for this quantity. We also confirm that this result is robust to changes in the definition of infinite string. It is possible that this result could account for the apparent absence of infinite string in recent lattice-free simulations.

James Robinson; Andrew Yates

1996-06-12T23:59:59.000Z

37

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

38

The Power Spectrum, Bias Evolution, and the Spatial Three-Point Correlation Function  

E-Print Network [OSTI]

We calculate perturbatively the normalized spatial skewness, $S_3$, and full three-point correlation function (3PCF), $\\zeta$, induced by gravitational instability of Gaussian primordial fluctuations for a biased tracer-mass distribution in flat and open cold-dark-matter (CDM) models. We take into account the dependence on the shape and evolution of the CDM power spectrum, and allow the bias to be nonlinear and/or evolving in time, using an extension of Fry's (1996) bias-evolution model. We derive a scale-dependent, leading-order correction to the standard perturbative expression for $S_3$ in the case of nonlinear biasing, as defined for the unsmoothed galaxy and dark-matter fields, and find that this correction becomes large when probing positive effective power-spectrum indices. This term implies that the inferred nonlinear-bias parameter, as usually defined in terms of the smoothed density fields, might depend on the chosen smoothing scale. In general, we find that the dependence of $S_3$ on the biasing scheme can substantially outweigh that on the adopted cosmology. We demonstrate that the normalized 3PCF, $Q$, is an ill-behaved quantity, and instead investigate $Q_V$, the variance-normalized 3PCF. The configuration dependence of $Q_V$ shows similarly strong sensitivities to the bias scheme as $S_3$, but also exhibits significant dependence on the form of the CDM power spectrum. Though the degeneracy of $S_3$ with respect to the cosmological parameters and constant linear- and nonlinear-bias parameters can be broken by the full configuration dependence of $Q_V$, neither statistic can distinguish well between evolving and non-evolving bias scenarios. We show that this can be resolved, in principle, by considering the redshift dependence of $\\zeta$.

Ari Buchalter; Marc Kamionkowski

1999-03-30T23:59:59.000Z

39

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

40

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

SciTech Connect (OSTI)

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

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.


41

What Does The PAMELA Antiproton Spectrum Tell Us About Dark Matter?  

E-Print Network [OSTI]

Measurements of the cosmic ray antiproton spectrum can be used to search for contributions from annihilating dark matter and to constrain the dark matter annihilation cross section. Depending on the assumptions made regarding cosmic ray propagation in the Galaxy, such constraints can be quite stringent. We revisit this topic, utilizing a set of propagation models fit to the cosmic ray boron, carbon, oxygen and beryllium data. We derive upper limits on the dark matter annihilation cross section and find that when the cosmic ray propagation parameters are treated as nuisance parameters (as we argue is appropriate), the resulting limits are significantly less stringent than have been previously reported. We also note (as have several previous groups) that simple GALPROP-like diffusion-reacceleration models predict a spectrum of cosmic ray antiprotons that is in good agreement with PAMELA's observations above ~5 GeV, but that significantly underpredict the flux at lower energies. Although the complexity of modeling cosmic ray propagation at GeV-scale energies makes it difficult to determine the origin of this discrepancy, we consider the possibility that the excess antiprotons are the result of annihilating dark matter. Suggestively, we find that this excess is best fit for a dark matter mass of approximately 35 GeV and annihilation cross section of approximately 1e-26 cm^3/s (to b-bbar), in good agreement with the mass and cross section previously shown to be required to generate the gamma-ray excess observed from the Galactic Center.

Dan Hooper; Tim Linden; Philipp Mertsch

2014-10-06T23:59:59.000Z

42

A Non-parametric Analysis of the CMB Power Spectrum  

E-Print Network [OSTI]

We examine Cosmic Microwave Background (CMB) temperature power spectra from the BOOMERANG, MAXIMA, and DASI experiments. We non-parametrically estimate the true power spectrum with no model assumptions. This is a significant departure from previous research which used either cosmological models or some other parameterized form (e.g. parabolic fits). Our non-parametric estimate is practically indistinguishable from the best fit cosmological model, thus lending independent support to the underlying physics that governs these models. We also generate a confidence set for the non-parametric fit and extract confidence intervals for the numbers, locations, and heights of peaks and the successive peak-to-peak height ratios. At the 95%, 68%, and 40% confidence levels, we find functions that fit the data with one, two, and three peaks respectively (0 8 sigma level. If we assume that there are three peaks in the data, we find their locations to be within l_1 = (118,300), l_2 = (377,650), and l_3 = (597,900). We find the ratio of the first peak-height to the second (Delta T_1)/(Delta T_2)^2= (1.06, 4.27) and the second to the third (Delta T_2)/(Delta T_3)^2= (0.41, 2.5). All measurements are for 95% confidence. If the standard errors on the temperature measurements were reduced to a third of what they are currently, as we expect to be achieved by the MAP and Planck CMB experiments, we could eliminate two-peak models at the 95% confidence limit. The non-parametric methodology discussed in this paper has many astrophysical applications.

Christopher J. Miller; Robert C. Nichol; Christopher Genovese; Larry Wasserman

2001-12-03T23:59:59.000Z

43

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

44

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

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Powered by Explorit Topic List Advanced Search Sample search results for: angular power spectrum Page: << < 1 2 3 4 5 > >> 1 V. The Thermal Beginning of the Summary: the...

45

CONSTRAINTS ON THE HIGH-l POWER SPECTRUM OF MILLIMETER-WAVE ANISOTROPIES FROM APEX-SZ  

SciTech Connect (OSTI)

We present measurements of the angular power spectrum of millimeter wave anisotropies with the APEX-SZ instrument. APEX-SZ has mapped 0.8 deg{sup 2} of sky at a frequency of 150 GHz with an angular resolution of 1'. These new measurements significantly improve the constraints on anisotropy power at 150 GHz over the range of angular multipoles 3000 < l < 10, 000, limiting the total astronomical signal in a flat band power to be less than 105 {mu}K{sup 2} at 95% CL. We expect both submillimeter-bright, dusty galaxies and to a lesser extent secondary cosmic microwave background anisotropies from the Sunyaev-Zel'dovich effect (SZE) to significantly contribute to the observed power. Subtracting the SZE power spectrum expected for {sigma}{sub 8} = 0.8 and masking bright sources, the best-fit value for the remaining power is C {sub l} = 1.1{sup +0.9} {sub -0.8} x 10{sup -5} {mu}K{sup 2} (1.7{sup +1.4} {sub -1.3} Jy{sup 2} sr{sup -1}). This agrees well with model predictions for power due to submillimeter-bright, dusty galaxies. Comparing this power to the power detected by BLAST at 600 GHz, we find the frequency dependence of the source fluxes to be S{sub {nu}}{proportional_to}{nu}{sup 2.6+0.4}{sub -0.2}} if both experiments measure the same population of sources. Simultaneously fitting for the amplitude of the SZE power spectrum and a Poisson-distributed point source population, we place an upper limit on the matter fluctuation amplitude of {sigma}{sub 8} < 1.18 at 95% confidence.

Reichardt, C. L.; Zahn, O.; Ferrusca, D.; Holzapfel, W. L.; Johnson, B. R.; Lee, A. T.; Lueker, M. [Department of Physics, University of California, Berkeley, CA 94720 (United States); Ade, P. A. R.; Lanting, T. [School of Physics and Astronomy, Cardiff University, CF24 3YB (United Kingdom); Basu, K.; Chon, G.; Kneissl, R. [Max Planck Institute for Radioastronomy, 53121 Bonn (Germany); Bender, A. N.; Halverson, N. W. [Center for Astrophysics and Space Astronomy, Department of Astrophysical and Planetary Sciences, University of Colorado, Boulder, CO 80309 (United States); Bertoldi, F. [Argelander Institute for Astronomy, Bonn University, Bonn (Germany); Cho, H.-M. [National Institute of Standards and Technology, Boulder, CO 80305 (United States); Dobbs, M.; Kennedy, J. [Department of Physics, McGill University, Montreal, H3A 2T8 (Canada); Horellou, C.; Johansson, D. [Onsala Space Observatory, Chalmers University of Technology, SE-439 92 Onsala (Sweden)] (and others)

2009-08-20T23:59:59.000Z

46

Physics 214 Notes on Cherenkov radiation Winter 2013 The power spectrum of Cherenkov radiation  

E-Print Network [OSTI]

Physics 214 Notes on Cherenkov radiation Winter 2013 The power spectrum of Cherenkov radiation. The radiation emitted by the charge is detected by an observer located at the point #x. We define the unit in time to a very good approximation. In class, we showed that the power spectrum for a radiating charge e

California at Santa Cruz, University of

47

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

48

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

49

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

E-Print Network [OSTI]

Power Control in Spectrum Overlay Networks: How to Cross a Multi-Lane Highway Wei Ren, Qing Zhao Research Laboratory, Adelphi, MD 20783 Email: aswami@arl.army.mil Abstract--We consider power control interference to primary users. We quantify the impact of the transmission power of secondary users

Islam, M. Saif

50

Power-laws and Non-Power-laws in Dark Matter Halos  

E-Print Network [OSTI]

Simulated dark matter profiles are often modelled as a `NFW' density profile rather than a single power law. Recently, attention has turned to the rather rigorous power-law behaviour exhibited by the `pseudo phase-space density' of the dark matter halo, which is defined dimensionally in terms of the local density and velocity dispersion of the dark matter particles. The non-power-law behaviour of the density profile is generally taken to exclude simple scale-free, in-fall models; however the power-law behaviour of the `pseudo-density' is a counter indication. We argue in this paper that both behaviours may be at least qualitatively understood in terms of a dynamically evolving self-similarity, rather than the form for self-similar infall that is fixed by cosmological initial conditions. The evolution is likely due to collective relaxation such as that provided by the radial-orbit instability on large scales. We deduce, from a distribution function given by first order coarse-graining, both the NFW-type density profile and the power-law pseudo-density profile. The results are not greatly sensitive to variation about 3 in the power of the velocity dispersion used in the definition of the phase space pseudo-density. We suggest that the power 2 may create the more physical quantity, whose deviations from a power-law are a diagnostic of incomplete relaxation.

R. N. Henriksen

2006-09-05T23:59:59.000Z

51

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

52

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

53

Modeling the affect of dark matter distributions in the Milky Way on the component of the cosmic rays energy spectrum as incident on Earth  

E-Print Network [OSTI]

In this thesis, we investigate the effect of dark matter distribution in the galaxy on the positron spectrum on earth. We wrote code to simulate two district dark matter distribution functions as well as the annihilations ...

Kamenetska, Masha

2005-01-01T23:59:59.000Z

54

Climate Change, Nuclear Power and Nuclear Proliferation: Magnitude Matters  

SciTech Connect (OSTI)

Integrated energy, environment and economics modeling suggests 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. Thus nuclear power may be needed to provide ~30% 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 proliferation risks are much greater, and more resistant to mitigation. The risks of nuclear power should be compared with the risks of the estimated 0.64oC long-term global surface-average temperature rise predicted if nuclear power were replaced with coal-fired power plants without carbon sequestration. Fusion energy, if developed, would provide a source of nuclear power with much lower proliferation risks than fission.

Robert J. Goldston

2010-03-03T23:59:59.000Z

55

Solar Gamma Rays Powered by Secluded Dark Matter  

E-Print Network [OSTI]

Secluded dark matter models, in which WIMPs 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.

Brian Batell; Maxim Pospelov; Adam Ritz; Yanwen Shang

2009-10-08T23:59:59.000Z

56

Increased Photovoltaic Power Output via Diffractive Spectrum Separation  

E-Print Network [OSTI]

In this Letter, we report the preliminary demonstration of a new paradigm for photovoltaic power generation that utilizes a broadband diffractive-optical element (BDOE) to efficiently separate sunlight into laterally spaced ...

Kim, Ganghun

57

Model independent foreground power spectrum estimation using WMAP 5-year data  

SciTech Connect (OSTI)

In this paper, we propose and implement on WMAP 5 yr data a model independent approach of foreground power spectrum estimation for multifrequency observations of the CMB experiments. Recently, a model independent approach of CMB power spectrum estimation was proposed by Saha et al. 2006. This methodology demonstrates that the CMB power spectrum can be reliably estimated solely from WMAP data without assuming any template models for the foreground components. In the current paper, we extend this work to estimate the galactic foreground power spectrum using the WMAP 5 yr maps following a self-contained analysis. We apply the model independent method in harmonic basis to estimate the foreground power spectrum and frequency dependence of combined foregrounds. We also study the behavior of synchrotron spectral index variation over different regions of the sky. We use the full sky Haslam map as an external template to increase the degrees of freedom, while computing the synchrotron spectral index over the frequency range from 408 MHz to 94 GHz. We compare our results with those obtained from maximum entropy method foreground maps, which are formed in pixel space. We find that relative to our model independent estimates maximum entropy method maps overestimate the foreground power close to galactic plane and underestimates it at high latitudes.

Ghosh, Tuhin; Souradeep, Tarun [IUCAA, Post Bag 4, Ganeshkhind, Pune-411007 (India); Saha, Rajib [IUCAA, Post Bag 4, Ganeshkhind, Pune-411007 (India); Jet Propulsion Laboratory, M/S 169-327, 4800 Oak Grove Drive, Pasadena, California 91109 (United States); California Institute of Technology, Pasadena, California 91125 (United States); Department of Physics, Indian Institute of Technology, Kanpur, U.P, 208016 (India); Jain, Pankaj [Department of Physics, Indian Institute of Technology, Kanpur, U.P, 208016 (India)

2009-06-15T23:59:59.000Z

58

Cosmic microwave background constraints on dark energy dynamics: analysis beyond the power spectrum  

E-Print Network [OSTI]

We consider the distribution of the non-Gaussian signal induced by weak lensing on the primary total intensity cosmic microwave background (CMB) anisotropies. Our study focuses on the three point statistics exploiting an harmonic analysis based on the CMB bispectrum. By considering the three multipoles as independent variables, we reveal a complex structure of peaks and valleys determined by the re-projection of the primordial acoustic oscillations through the lensing mechanism. We study the dependence of this system on the expansion rate at the epoch in which the weak lensing power injection is relevant, probing the dark energy equation of state at redshift corresponding to the equivalence with matter or higher ($w_\\infty$). We evaluate the impact of the bispectrum observable on the CMB capability of constraining the dark energy dynamics. We perform a maximum likelihood analysis by varying the dark energy abundance, the present equation of state $w_0$ and $w_\\infty$. We show that the projection degeneracy affecting a pure power spectrum analysis in total intensity is broken if the bispectrum is taken into account. For a Planck-like experiment, assuming nominal performance, no foregrounds or systematics, and fixing all the parameters except $w_0$, $w_\\infty$ and the dark energy abundance, a percent and ten percent precision measure of $w_0$ and $w_\\infty$ is achievable from CMB data only. These results indicate that the detection of the weak lensing signal by the forthcoming CMB probes may be relevant to gain insight into the dark energy dynamics at the onset of cosmic acceleration.

Fabio Giovi; Carlo Baccigalupi; Francesca Perrotta

2005-05-18T23:59:59.000Z

59

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

SciTech Connect (OSTI)

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

60

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

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

Climate Change, Nuclear Power and Nuclear Proliferation: Magnitude Matters  

SciTech Connect (OSTI)

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

62

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

63

Reliable self-powered highly spectrum-selective ZnO ultraviolet photodetectors  

SciTech Connect (OSTI)

Ultraviolet photodetectors (PDs) have been fabricated from p-ZnO:(Li,N)/n-ZnO structures in this Letter. The PDs can operate without any external power supply and show response only to a very narrow spectrum range. The self-power character of the devices is due to the built-in electric field in the p-n junctions that can separate the photogenerated electrons and holes while the high spectrum-selectivity has been attributed to the filter effect of the neutral region in the ZnO:(Li,N) layer. The performance of the self-powered highly spectrum-selective PDs degrades little after five months, indicating their good reliability.

Shen, H. [State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033 (China) [State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Shan, C. X., E-mail: shancx@ciomp.ac.cn, E-mail: binghuili@163.com; Li, B. H., E-mail: shancx@ciomp.ac.cn, E-mail: binghuili@163.com; Shen, D. Z. [State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033 (China)] [State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033 (China); Xuan, B. [Key Laboratory of Optical System Advanced Manufacturing Technology, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033 (China)] [Key Laboratory of Optical System Advanced Manufacturing Technology, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033 (China)

2013-12-02T23:59:59.000Z

64

No evidence for the blue-tilted power spectrum of relic gravitational waves  

E-Print Network [OSTI]

In this paper, we constrain the tilt of the power spectrum of relic gravitational waves by combining the data from BICEP2/Keck array and Planck (BKP) and the Laser Interferometer Gravitational-Waves Observatory (LIGO). From the data of BKP B-modes, the constraint on the tensor tilt is $n_t=0.66^{+1.83}_{-1.44}$ at the $68%$ confidence level. By further adding the LIGO upper limit on the energy density of gravitational waves, the constraint becomes $n_t=-0.76^{+1.37}_{-0.52}$ at the $68%$ confidence level. We conclude that there is no evidence for a blue-tilted power spectrum of relic gravitational waves and either sign of the index of tensor power spectrum is compatible with the data.

Huang, Qing-Guo

2015-01-01T23:59:59.000Z

65

No evidence for the blue-tilted power spectrum of relic gravitational waves  

E-Print Network [OSTI]

In this paper, we constrain the tilt of the power spectrum of relic gravitational waves by combining the data from BICEP2/Keck array and Planck (BKP) and the Laser Interferometer Gravitational-Waves Observatory (LIGO). From the data of BKP B-modes, the constraint on the tensor tilt is $n_t=0.66^{+1.83}_{-1.44}$ at the $68%$ confidence level. By further adding the LIGO upper limit on the energy density of gravitational waves, the constraint becomes $n_t=-0.76^{+1.37}_{-0.52}$ at the $68%$ confidence level. We conclude that there is no evidence for a blue-tilted power spectrum of relic gravitational waves and either sign of the index of tensor power spectrum is compatible with the data.

Qing-Guo Huang; Sai Wang

2015-02-09T23:59:59.000Z

66

Mass spectrum of diquarks and mesons in the color--flavor locked phase of dense quark matter  

E-Print Network [OSTI]

The spectrum of meson and diquark excitations of dense quark matter is considered in the framework of the Nambu -- Jona-Lasinio model with three types of massless quarks in the presense of a quark number chemical potential $\\mu$. We investigate the effective action of meson- and diquark fields both at sufficiently large values of $\\mu>\\mu_c\\approx 330$ MeV, where the color--flavor locked (CFL) phase is realized, and in the chirally broken phase of quark matter ($\\mu\\mu_c$.

Ebert, D; Yudichev, V L

2007-01-01T23:59:59.000Z

67

Effect of Compressing the Dynamic Range of the Power Spectrum in Modulation Filtering Based Speech Enhancement  

E-Print Network [OSTI]

.paliwal@griffith.edu.au Abstract In the modulation-filtering based speech enhancement method, noise suppression is achieved systematically different dynamic range compression functions applied to the power spectrum for speech enhancement- gibility of the enhanced speech. The quality is measured objec- tively in terms of the Perceptual

68

A Bayesian approach to power-spectrum significance estimation, with application to solar neutrino data  

E-Print Network [OSTI]

The usual procedure for estimating the significance of a peak in a power spectrum is to calculate the probability of obtaining that value or a larger value by chance, on the assumption that the time series contains only noise (e.g. that the measurements were derived from random samplings of a Gaussian distribution). However, it is known that one should regard this P-Value approach with caution. As an alternative, we here examine a Bayesian approach to estimating the significance of a peak in a power spectrum. This approach requires that we consider explicitly the hypothesis that the time series contains a periodic signal as well as noise. The challenge is to identify a probability distribution function for the power that is appropriate for this hypothesis. We propose what seem to be reasonable conditions to require of this function, and then propose a simple function that meets these requirements. We also propose a consistency condition, and check to see that our function satisfies this condition. We find that the Bayesian significance estimates are considerably more conservative than the conventional estimates. We apply this procedure to three recent analyses of solar neutrino data: (a) bimodality of GALLEX data; (b) power spectrum analysis of Super-Kamiokande data; and (c) the combined analysis of radiochemical neutrino data and irradiance data.

P. A. Sturrock

2008-09-01T23:59:59.000Z

69

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.

Suratna Das; Gaurav Goswami; Jayanti Prasad; Raghavan Rangarajan

2014-12-22T23:59:59.000Z

70

Peaks and Troughs in Helioseismology: The Power Spectrum of Solar Oscillations  

E-Print Network [OSTI]

I present a matched-wave asymptotic analysis of the driving of solar oscillations by a general localised source. The analysis provides a simple mathematical description of the asymmetric peaks in the power spectrum in terms of the relative locations of eigenmodes and troughs in the spectral response. It is suggested that the difference in measured phase function between the modes and the troughs in the spectrum will provide a key diagnostic of the source of the oscillations. I also suggest a form for the asymmetric line profiles to be used in the fitting of solar power spectra. Finally I present a comparison between the numerical and asymptotic descriptions of the oscillations. The numerical results bear out the qualitative features suggested by the asymptotic analysis but suggest that numerical calculations of the locations of the troughs will be necessary for a quantitative comparison with the observations.

Colin S. Rosenthal

1998-04-03T23:59:59.000Z

71

A search for signatures of dark matter in the AMS-01 electron and antiproton spectrum  

E-Print Network [OSTI]

If dark matter consists of Weakly Interacting Massive Particles (WIMPs), such as the supersymmetric neutralino, various theories predict that their annihilation in the galaxy can give rise to anomalous features in the ...

Carosi, Gianpaolo Patrick

2006-01-01T23:59:59.000Z

72

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

73

VES-0071- In the Matter of Mississippi Power Company  

Broader source: Energy.gov [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...

74

Angular Signatures of Dark Matter in the Diffuse Gamma Ray Spectrum  

SciTech Connect (OSTI)

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

75

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

2009-01-10T23:59:59.000Z

76

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

77

SECOND SEASON QUIET OBSERVATIONS: MEASUREMENTS OF THE COSMIC MICROWAVE BACKGROUND POLARIZATION POWER SPECTRUM AT 95 GHz  

SciTech Connect (OSTI)

The Q/U Imaging ExperimenT (QUIET) has observed the cosmic microwave background (CMB) at 43 and 95 GHz. The 43 GHz results have been published in a previous paper, and here we report the measurement of CMB polarization power spectra using the 95 GHz data. This data set comprises 5337 hr of observations recorded by an array of 84 polarized coherent receivers with a total array sensitivity of 87 {mu}K{radical}s. Four low-foreground fields were observed, covering a total of {approx}1000 deg{sup 2} with an effective angular resolution of 12.'8, allowing for constraints on primordial gravitational waves and high signal-to-noise measurements of the E-modes across three acoustic peaks. The data reduction was performed using two independent analysis pipelines, one based on a pseudo-C {sub l} (PCL) cross-correlation approach, and the other on a maximum-likelihood (ML) approach. All data selection criteria and filters were modified until a predefined set of null tests had been satisfied before inspecting any non-null power spectrum. The results derived by the two pipelines are in good agreement. We characterize the EE, EB, and BB power spectra between l = 25 and 975 and find that the EE spectrum is consistent with {Lambda}CDM, while the BB power spectrum is consistent with zero. Based on these measurements, we constrain the tensor-to-scalar ratio to r = 1.1{sup +0.9} {sub -0.8} (r < 2.8 at 95% C.L.) as derived by the ML pipeline, and r = 1.2{sup +0.9} {sub -0.8} (r < 2.7 at 95% C.L.) as derived by the PCL pipeline. In one of the fields, we find a correlation with the dust component of the Planck Sky Model, though the corresponding excess power is small compared to statistical errors. Finally, we derive limits on all known systematic errors, and demonstrate that these correspond to a tensor-to-scalar ratio smaller than r = 0.01, the lowest level yet reported in the literature.

Araujo, D.; Dumoulin, R. N.; Newburgh, L. B.; Zwart, J. T. L. [Department of Physics and Columbia Astrophysics Laboratory, Columbia University, New York, NY 10027 (United States); Bischoff, C.; Brizius, A.; Buder, I.; Kusaka, A. [Kavli Institute for Cosmological Physics, Department of Physics, Enrico Fermi Institute, The University of Chicago, Chicago, IL 60637 (United States); Chinone, Y. [High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); Cleary, K.; Reeves, R. [Cahill Center for Astronomy and Astrophysics, California Institute of Technology, 1200 E. California Blvd M/C 249-17, Pasadena, CA 91125 (United States); Monsalve, R.; Bustos, R. [Department of Physics, University of Miami, 1320 Campo Sano Drive, Coral Gables, FL 33146 (United States); Naess, S. K.; Eriksen, H. K. [Institute of Theoretical Astrophysics, University of Oslo, P.O. Box 1029 Blindern, NO-0315 Oslo (Norway); Wehus, I. K. [Department of Astrophysics, University of Oxford, Keble Road, Oxford OX1 3RH (United Kingdom); Bronfman, L. [Departamento de Astronomia, Universidad de Chile, Casilla 36-D, Santiago (Chile); Church, S. E. [Kavli Institute for Particle Astrophysics and Cosmology and Department of Physics, Stanford University, Varian Physics Building, 382 Via Pueblo Mall, Stanford, CA 94305 (United States); Dickinson, C. [Jodrell Bank Centre for Astrophysics, Alan Turing Building, School of Physics and Astronomy, The University of Manchester, Oxford Road, Manchester M13 9PL (United Kingdom); Gaier, T., E-mail: ibuder@uchicago.edu [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Collaboration: QUIET Collaboration; and others

2012-12-01T23:59:59.000Z

78

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

79

Early structure formation from primordial density fluctuations with a blue-tilted power spectrum  

E-Print Network [OSTI]

While observations of large-scale structure and the cosmic microwave background (CMB) provide strong constraints on the amplitude of the primordial power spectrum (PPS) on scales larger than 10 Mpc, the amplitude of the power spectrum on sub-galactic length scales is much more poorly constrained. We study early structure formation in a cosmological model with a blue-tilted PPS. We assume that the standard scale-invariant PPS is modified at small length scales as $P(k) \\sim k^{m_{\\rm s}}$ with $m_{\\rm s} > 1$. We run a series of cosmological hydrodynamic simulations to examine the dependence of the formation epoch and the characteristic mass of primordial stars on the tilt of the PPS. In models with $m_{\\rm s} > 1$, star-forming gas clouds are formed at $z > 100$, when formation of hydrogen molecules is inefficient because the intense CMB radiation destroys chemical intermediates. Without efficient coolant, the gas clouds gravitationally contract while keeping a high temperature. The protostars formed in such ...

Hirano, Shingo; Yoshida, Naoki; Spergel, David; Yorke, Harold W

2015-01-01T23:59:59.000Z

80

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

Note: This page contains sample records for the topic "matter power spectrum" from the National Library of EnergyBeta (NLEBeta).
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81

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

82

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

83

Mass spectrum of diquarks and mesons in the color--flavor locked phase of dense quark matter  

E-Print Network [OSTI]

The spectrum of meson and diquark excitations of dense quark matter is considered in the framework of the Nambu -- Jona-Lasinio model with three types of massless quarks in the presense of a quark number chemical potential $\\mu$. We investigate the effective action of meson- and diquark fields both at sufficiently large values of $\\mu>\\mu_c\\approx 330$ MeV, where the color--flavor locked (CFL) phase is realized, and in the chirally broken phase of quark matter ($\\muphase the pseudoscalar diquarks are not allowed to exist as stable particles, but the scalar diquarks might be stable only at a rather strong interaction in the diquark channel. In the case of the CFL phase, all NG bosons of the model are realized as scalar and pseudoscalar diquarks. Moreover, it turns out that massive diquark excitations are unstable for this phase. In particular, for the scalar and pseudoscalar octets of diquark resonances a mass value around 230 MeV was found numerically. In contrast, mesons are stable particles in the CFL phase. Their masses lie in the interval 400$\\div$500 MeV for not too large values of $\\mu>\\mu_c$.

D. Ebert; K. G. Klimenko; V. L. Yudichev

2007-09-25T23:59:59.000Z

84

PARAMETRIC TENSION BETWEEN EVEN AND ODD MULTIPOLE DATA OF THE WMAP POWER SPECTRUM: UNACCOUNTED CONTAMINATION OR MISSING PARAMETERS?  

SciTech Connect (OSTI)

There exists power contrast in even and odd multipoles of the WMAP power spectrum at low and intermediate multipole ranges. This anomaly is explicitly associated with the angular power spectrum, which is heavily used for cosmological model fitting. Having noted this, we have investigated whether even (odd) multipole data set is individually consistent with the WMAP concordance model. Our investigation shows that the WMAP concordance model does not make a good fit for even (odd) multipole data set, which indicates parametric tension between even and odd multipole data set. Noting that tension is highest in primordial power spectrum parameters, we have additionally considered a running spectral index, but found that tension increases to even a higher level. We believe these parametric tensions may be indications of unaccounted contamination or imperfection of the model.

Kim, Jaiseung; Naselsky, Pavel, E-mail: jkim@nbi.d [Niels Bohr Institute and Discovery Center, Blegdamsvej 17, DK-2100 Copenhagen (Denmark)

2010-12-01T23:59:59.000Z

85

Time Variations of the Superkamiokande Solar Neutrino Flux Data by Rayleigh Power Spectrum Analysis  

E-Print Network [OSTI]

We have used the Rayleigh Power Spectrum Analysis of the solar neutrino flux data from 1) 5-day-long samples from Super-Kamiokande-I detector during the period from June, 1996 to July, 2001; 2) 10 -day-long samples from the same detector during the same period and (3) 45-day long from the same detector during the same period. According to our analysis (1) gives periodicities around 0.25, 23.33, 33.75 and 42.75 months; (2) exhibits periodicities around 0.5, 1.0, 28.17, 40.67 and 52.5 months and (3) shows periodicities around 16.5 and 28.5 months. We have found almost similar periods in the solar flares, sunspot data, solar proton data.

Koushik Ghosh; Probhas Raychaudhuri

2006-06-05T23:59:59.000Z

86

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

SciTech Connect (OSTI)

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

87

Transmission Matters Now: How Will Power Market Regulations Impact the Industrial's Power Supply Costs and Reliability?  

E-Print Network [OSTI]

The standardization of the power market structure and transmission access rules will result in new rules for dealing with the transmission systems. Furthermore, transmission system limitations and market inadequacies will have a significant impact...

James, F.; Beidas, H.; Fox, R.

88

Power-spectrum analysis of Super-Kamiokande solar neutrino data, taking into account asymmetry in the error estimates  

E-Print Network [OSTI]

The purpose of this article is to carry out a power-spectrum analysis (based on likelihood methods) of the Super-Kamiokande 5-day dataset that takes account of the asymmetry in the error estimates. Whereas the likelihood analysis involves a linear optimization procedure for symmetrical error estimates, it involves a nonlinear optimization procedure for asymmetrical error estimates. We find that for most frequencies there is little difference between the power spectra derived from analyses of symmetrized error estimates and from asymmetrical error estimates. However, this proves not to be the case for the principal peak in the power spectra, which is found at 9.43 yr-1. A likelihood analysis which allows for a "floating offset" and takes account of the start time and end time of each bin and of the flux estimate and the symmetrized error estimate leads to a power of 11.24 for this peak. A Monte Carlo analysis shows that there is a chance of only 1% of finding a peak this big or bigger in the frequency band 1 - 36 yr-1 (the widest band that avoids artificial peaks). On the other hand, an analysis that takes account of the error asymmetry leads to a peak with power 13.24 at that frequency. A Monte Carlo analysis shows that there is a chance of only 0.1% of finding a peak this big or bigger in that frequency band 1 - 36 yr-1. From this perspective, power spectrum analysis that takes account of asymmetry of the error estimates gives evidence for variability that is significant at the 99.9% level. We comment briefly on an apparent discrepancy between power spectrum analyses of the Super-Kamiokande and SNO solar neutrino experiments.

P. A. Sturrock; J. D. Scargle

2006-06-20T23:59:59.000Z

89

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

90

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

SciTech Connect (OSTI)

When power production at The Geysers geothermal power complex began to falter, the National Renewable Energy Laboratory (NREL) stepped in, developing advanced condensing technology that dramatically boosted production efficiency - and making a major contribution to the effective use of geothermal power. NREL developed advanced direct-contact condenser (ADCC) technology to condense spent steam more effectively, improving power production efficiency in Unit 11 by 5%.

Not Available

2010-12-01T23:59:59.000Z

91

The effect of surface irradiance on the absorption spectrum of chromophoric dissolved organic matter in the global ocean  

E-Print Network [OSTI]

.2 mm), is responsible for nearly 90% of ultraviolet (UV) radiation attenuation in the global ocean matter in the global ocean Chantal M. Swan a,n , Norman B. Nelson a , David A. Siegel a,b , Tihomir S to better assess the impact of CDOM on surface ocean photochemistry and remote sensing of ocean color

Siegel, David A.

92

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

SciTech Connect (OSTI)

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.

Not Available

2010-12-01T23:59:59.000Z

93

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 latest solar models, the obtained results tend to favor a solar core rotating significantly faster than the rest of the radiative zone. In the framework of the Phoebus group, we have also applied the same methodology to other helioseismology instruments on board SoHO and ground based networks.

R. A. Garcia; S. Turck-Chieze; S. J. Jimenez-Reyes; J. Ballot; P. L. Palle; A. Eff-Darwich; S. Mathur; J. Provost

2006-11-27T23:59:59.000Z

94

Review of Methods of Power-Spectrum Analysis as Applied to Super-Kamiokande Solar Neutrino Data  

E-Print Network [OSTI]

To help understand why different published analyses of the Super-Kamiokande solar neutrino data arrive at different conclusions, we have applied six different methods to a standardized problem. The key difference between the various methods rests in the amount of information that each processes. A Lomb-Scargle analysis that uses the mid times of the time bins and ignores experimental error estimates uses the least information. A likelihood analysis that uses the start times, end times, and mean live times, and takes account of the experimental error estimates, makes the greatest use of the available information. We carry out power-spectrum analyses of the Super-Kamiokande 5-day solar neutrino data, using each method in turn, for a standard search band (0 to 50 yr-1). For each method, we also carry out a fixed number (10,000) of Monte-Carlo simulations for the purpose of estimating the significance of the leading peak in each power spectrum. We find that, with one exception, the results of these calculations are compatible with those of previously published analyses. (We are unable to replicate Koshio's recent results.) We find that the significance of the peaks at 9.43 yr-1 and at 43.72 yr-1 increases progressively as one incorporates more information into the analysis procedure.

P. A. Sturrock

2004-08-02T23:59:59.000Z

95

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

96

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

97

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

98

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

SciTech Connect (OSTI)

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

99

Power Spectrum Analysis of Physikalisch-Technische Bundesanstalt Decay-Rate Data: Evidence for Solar Rotational Modulation  

E-Print Network [OSTI]

Evidence for an anomalous annual periodicity in certain nuclear decay data has led to speculation concerning a possible solar influence on nuclear processes. We have recently analyzed data concerning the decay rates of Cl-36 and Si-32, acquired at the Brookhaven National Laboratory (BNL), to search for evidence that might be indicative of a process involving solar rotation. Smoothing of the power spectrum by weighted-running-mean analysis leads to a significant peak at frequency 11.18/yr, which is lower than the equatorial synodic rotation rates of the convection and radiative zones. This article concerns measurements of the decay rates of Ra-226 acquired at the Physikalisch-Technische Bundesanstalt (PTB) in Germany. We find that a similar (but not identical) analysis yields a significant peak in the PTB dataset at frequency 11.21/yr, and a peak in the BNL dataset at 11.25/yr. The change in the BNL result is not significant since the uncertainties in the BNL and PTB analyses are estimated to be 0.13/yr and 0.07/yr, respectively. Combining the two running means by forming the joint power statistic leads to a highly significant peak at frequency 11.23/yr. We comment briefly on the possible implications of these results for solar physics and for particle physics.

P. A. Sturrock; J. B. Buncher; E. Fischbach; J. T. Gruenwald; D. Javorsek II; J. H. Jenkins; R. H. Lee; J. J. Mattes; J. R. Newport

2010-10-11T23:59:59.000Z

100

Power-Spectrum Analyses of Super-Kamiokande Solar Neutrino Data: Variability and its Implications for Solar Physics and Neutrino Physics  

E-Print Network [OSTI]

There have been conflicting claims as to whether or not power-spectrum analysis of the Super-Kamiokande solar neutrino data yields evidence of variability. Comparison of these claims is complicated by the fact that the relevant articles may use different datasets, different methods of analysis, and different procedures for significance estimation. The purpose of this article is to clarify the role of power spectrum analysis. To this end, we analyze only the Super-Kamiokande 5-day dataset, and we use a standard procedure for significance estimation proposed by the Super-Kamiokande collaboration. We then analyze this dataset, with this method of significance estimation, using six methods of power spectrum analysis. We find that the significance of the principal peak in the power spectrum (that at 9.43 yr-1with a depth of modulation of 7%) shows a clear correlation with the amount and relevance of the information being processed, as would be expected if there were a real signal in the data. The significance level reaches 99.3% for one method of analysis. We discuss, in terms of sub-dominant processes, possible neutrino-physics interpretations of the apparent variability of the Super-Kamiokande measurements, and we suggest steps that could be taken to resolve the question of variability of the solar neutrino flux.

P. A. Sturrock; D. O. Caldwell; J. D. Scargle; M. S. Wheatland

2005-08-08T23:59:59.000Z

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101

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

SciTech Connect (OSTI)

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

102

Generation of primordial cosmological density inhomogeneities with scale invariant power spectrum during the standard radiation dominated expansion of the universe  

E-Print Network [OSTI]

The expansion/contraction of a bubble of gas of radius $R_0(t)$ immersed in an incompressible fluid that fills the infinite 3D space around it, $r \\ge R_0(t)$, generates a radial flow, ${\\vec v}(r,t) = \\frac{R^2_0(t)}{r^2}\\ \\dot{R}_0(t) {\\hat r}$, which is set by the velocity of the bubble surface, $\\dot{R}_0(t)$. The kinetic energy that the expanding/contracting bubble pumps, at the expense of its own internal energy, into each unit volume of the flowing incompressible fluid is ${\\it e}(r,t) = \\frac{\\rho_0}{2} |{\\vec v}(r,t)|^2 = \\frac{\\rho_0}{2} \\dot{R}^2_0(t) R^4_0(t) r^{-4}$, where $\\rho_0$ is the mass density of the fluid. This incompressible flow generates equal time energy density (anti)correlations over infinitely long distances. They are imposed by global conservation laws and, therefore, do not violate causality. We notice that energy density inhomogeneities that are (anti)correlated as $f(r) \\sim - r^{-4}$ as $r \\to \\infty$ have scale invariant power spectrum in the range of very small wavenumbers,...

Oaknin, David H

2007-01-01T23:59:59.000Z

103

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

104

Dark matter, a new proof of the predictive power of general relativity  

E-Print Network [OSTI]

Without observational or theoretical modifications, Newtonian and general relativity seem to be unable to explain gravitational behavior of large structure of the universe. The assumption of dark matter solves this problem without modifying theories. But it implies that most of the matter in the universe must be unobserved matter. Another solution is to modify gravitation laws. In this article, we study a third way that does not modify gravitation of general relativity and not modify the matter's distribution, by using gravitomagnetism in a new physical context. Compare with Newtonian gravitation, it leads to add a new component without changing the gravity field. As already known, we retrieve that this new component is generally small enough to be undetectable. But we will see that the galaxies clusters can generate a significant component and embed large structure of universe. We show that the magnitude of this embedding component is once again small enough to be in agreement with current experimental resul...

Corre, Stéphane Le

2015-01-01T23:59:59.000Z

105

Power Spectrum Analysis of LMSU (Lomonosov Moscow State University) Nuclear Decay-Rate Data: Further Indication of r-Mode Oscillations in an Inner Solar Tachocline  

E-Print Network [OSTI]

This article presents a power-spectrum analysis of 2,350 measurements of the $^{90}$Sr/$^{90}$Y decay process acquired over the interval 4 August 2002 to 6 February 2009 at the Lomonosov Moscow State University (LMSU). As we have found for other long sequences of decay measurements, the power spectrum is dominated by a very strong annual oscillation. However, we also find a set of low-frequency peaks, ranging from 0.26 year$^{-1}$ to 3.98 year$^{-1}$, which are very similar to an array of peaks in a power spectrum formed from Mt Wilson solar diameter measurements. The Mt Wilson measurements have been interpreted in terms of r-mode oscillations in a region where the sidereal rotation frequency is 12.08 year$^{-1}$. We find that the LMSU measurements may also be attributed to the same type of r-mode oscillations in a solar region with the same sidereal rotation frequency. We propose that these oscillations occur in an inner tachocline that separates the radiative zone from a more slowly rotating solar core.

Peter A. Sturrock; Alexander G. Parkhomov; Ephraim Fischbach; Jere H. Jenkins

2012-03-14T23:59:59.000Z

106

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

107

Condensed Matter Cluster Reactions in LENR Power Cells for a Radical New Type of Space Power Source  

SciTech Connect (OSTI)

This paper reviews previous theoretical and experimental study on the possibility of nuclear events in multilayer thin film electrodes (Lipson et al., 2004 and 2005; Miley et al., 2007), including the correlation between excess heat and transmutations (Miley and Shrestha, 2003) and the cluster theory that predicts it. As a result of this added understanding of cluster reactions, a new class of electrodes is under development at the University of Illinois. These electrodes are designed to enhance cluster formation and subsequent reactions. Two approaches are under development. The first employs improved loading-unloading techniques, intending to obtain a higher volumetric density of sites favoring cluster formation. The second is designed to create nanostructures on the electrode where the cluster state is formed by electroless deposition of palladium on nickel micro structures. Power units employing these electrodes should offer unique advantages for space applications. This is a fundamental new nuclear energy source that is environmentally compatible with a minimum of radiation involvement, high specific power, very long lifetime, and scalable from micro power to kilowatts.

Yang Xiaoling; Miley, George H.; Hora, Heinz [University of Illinois Urbana-Champaign, NPL Associates, Urbana, IL 217-333-3772 (United States); Department of Theoretical Physics Univ. of New South Wales Sydney (Australia)

2009-03-16T23:59:59.000Z

108

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

E-Print Network [OSTI]

risk associated with CO2 emissions under potential climateimpact in terms of CO2 emissions of these power plants,gas, or wind, annual CO2 emissions from these 5,000 plants

Barradale, Merrill Jones

2010-01-01T23:59:59.000Z

109

Precision reconstruction of the dark matter-neutrino relative velocity from N-body simulations  

E-Print Network [OSTI]

Discovering the mass of neutrinos is a principle goal in high energy physics and cosmology. In addition to cosmological measurements based on two-point statistics, the neutrino mass can also be estimated by observations of neutrino wakes resulting from the relative motion between dark matter and neutrinos. Such a detection relies on an accurate reconstruction of the dark matter-neutrino relative velocity which is affected by non-linear structure growth and galaxy bias. We investigate our ability to reconstruct this relative velocity using large N-body simulations where we evolve neutrinos as distinct particles alongside the dark matter. We find that the dark matter velocity power spectrum is overpredicted by linear theory whereas the neutrino velocity power spectrum is underpredicted. The magnitude of the relative velocity observed in the simulations is found to be lower than what is predicted in linear theory. Since neither the dark matter nor the neutrino velocity fields are directly observable from galaxy ...

Inman, Derek; Pen, Ue-Li; Farchi, Alban; Yu, Hao-Ran; Harnois-Deraps, Joachim

2015-01-01T23:59:59.000Z

110

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

SciTech Connect (OSTI)

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

111

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

112

An angular power spectrum analysis of the DRAO 1.4 GHz polarization survey: implications for CMB observations  

E-Print Network [OSTI]

The aim of the present analysis is to improve the knowledge of the statistical properties of the Galactic diffuse synchrotron emission, which constrains sensitive CMB anisotropy measurements. We have analysed the new DRAO 1.4 GHz polarization survey together with the Stockert 1.4 GHz total intensity survey and derived the angular power spectra (APSs) of the total intensity, the polarized emission, and their cross-correlation for the entire surveys and for three low-intensity regions. The APSs of the diffuse synchrotron emission are modelled by power laws. For the $E$ and $B$ modes, a slope of $\\alpha \\sim [-3.0,-2.5]$ for the multipole range $\\sim [30,300]$ is found. By the extrapolation of these results to 70 GHz, we can estimate the Galactic synchrotron contamination of CMB anisotropies, and we find results that are compatible with the ones coming from WMAP 3-yr data. In the low-intensity regions, the cosmological primordial B~mode peak at $\\ell \\sim 100$ should be clearly observable for a tensor-to-scalar ...

La Porta, L; Reich, W; Reich, P

2006-01-01T23:59:59.000Z

113

The X-ray Power Density Spectrum of the Seyfert 2 Galaxy NGC 4945: Analysis and Application of the Method of Light Curve Simulations  

SciTech Connect (OSTI)

The study of the power density spectrum (PDS) of fluctuations in the X-ray flux from active galactic nuclei (AGN) complements spectral studies in giving us a view into the processes operating in accreting compact objects. An important line of investigation is the comparison of the PDS from AGN with those from galactic black hole binaries; a related area of focus is the scaling relation between time scales for the variability and the black hole mass. The PDS of AGN is traditionally modeled using segments of power laws joined together at so-called break frequencies; associations of the break time scales, i.e., the inverses of the break frequencies, with time scales of physical processes thought to operate in these sources are then sought. I analyze the Method of Light Curve Simulations that is commonly used to characterize the PDS in AGN with a view to making the method as sensitive as possible to the shape of the PDS. I identify several weaknesses in the current implementation of the method and propose alternatives that can substitute for some of the key steps in the method. I focus on the complications introduced by uneven sampling in the light curve, the development of a fit statistic that is better matched to the distributions of power in the PDS, and the statistical evaluation of the fit between the observed data and the model for the PDS. Using archival data on one AGN, NGC 3516, I validate my changes against previously reported results. I also report new results on the PDS in NGC 4945, a Seyfert 2 galaxy with a well-determined black hole mass. This source provides an opportunity to investigate whether the PDS of Seyfert 1 and Seyfert 2 galaxies differ. It is also an attractive object for placement on the black hole mass-break time scale relation. Unfortunately, with the available data on NGC 4945, significant uncertainties on the break frequency in its PDS remain.

Mueller, Martin; /SLAC

2010-12-16T23:59:59.000Z

114

Predictions on the angular power spectrum of clustered extragalactic point sources at CMB frequencies from flat and all--sky 2D-simulations  

E-Print Network [OSTI]

We present predictions on the angular power spectrum of CMB fluctuations due to extragalactic point sources (EPS) by using a method for simulating realistic 2D distributions of clustered EPS. Both radio and far--IR selected source populations are taken into account. To analyze different clustering scenarios, we exploit angular power spectra of EPS, $P(k)$, estimated either by data coming from currently available surveys or by means of theoretical predictions. By adopting the source number counts predicted by the Toffolatti et al. (1998) evolution model -- capable of accounting well for the available data at radio cm wavelengths -- we are able to reproduce current data on the two--point angular correlation functions, $w(\\theta)$, of radio sources. We can confirm that the detection of primordial CMB anisotropies is not hampered by undetected clustered sources at frequencies $\\leq 150-200$ GHz. On the other hand, our current findings show that at higher frequencies the clustering signal could severely reduce the detectability of intrinsic CMB anisotropies, thus confirming previous theoretical predictions. We also show that unsubtracted EPS can account for the excess signal at high multipoles detected by recent CMB anisotropy experiments. Moreover, the additional power due to the clustering of sources gives rise to a small but not negligible contribution to the same excess signal. As a final result, we also present an example of a currently feasible {\\it realistic map} of EPS at 70 GHz, by taking into account data on bright detected sources as well as the previously quoted model for number counts.

J. González-Nuevo; L. Toffolatti; F. Argüeso

2004-11-12T23:59:59.000Z

115

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

116

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

117

Changes in the halo formation rates due to features in the primordial spectrum  

E-Print Network [OSTI]

Features in the primordial scalar power spectrum provide a possible roadway to describe the outliers at the low multipoles in the WMAP data. Apart from the CMB angular power spectrum, these features can also alter the matter power spectrum and, thereby, the formation of the large scale structure. Carrying out a complete numerical analysis, we investigate the effects of primordial features on the formation rates of the halos. We consider a few different inflationary models that lead to features in the scalar power spectrum and an improved fit to the CMB data, and analyze the corresponding imprints on the formation of halos. Performing a Markov Chain Monte Carlo analysis with the WMAP seven year data and the SDSS halo power spectrum from LRG DR7 for the models of our interest, we arrive at the parameter space of the models allowed by the data. We illustrate that, inflationary potentials, such as the quadratic potential with sinusoidal modulations and the axion monodromy model, which generate certain repeated, o...

Hazra, Dhiraj Kumar

2012-01-01T23:59:59.000Z

118

Time Variations of the Solar Neutrino Flux Data from Sage and Gallex-Gno Detectors Obtained by Rayleigh Power Spectrum Analysis  

E-Print Network [OSTI]

We have used Rayleigh power spectrum analysis of the monthly solar neutrino flux data from (1) SAGE detector during the period from 1st January 1990 to 31st December 2000; (2) SAGE detector during the period from April 1998 to December 2001; (3) GALLEX detector during the period from May 1991 to January 1997; (4) GNO detector during the period from May 1998 to December 2001; (5) GALLEX-GNO detector (combined data) from May 1991 to December 2001 and (6) average of the data from GNO and SAGE detectors during the period from May 1998 to December 2001. (1) exhibits periodicity around 1.3, 4.3, 5.5, 6.3, 7.9, 8.7, 15.9, 18.7, 23.9, 32.9 and 48.7 months. (2) shows periodicity around 1.5, 2.9, 4.5, 10.1 months. For (3) we observe periodicity around 1.7, 18.7 and 26.9 months. For (4) periodicity is seen around 3.5, 5.5, 7.7 and 10.5 months. (5) gives periodicity around 1.7, 18.5, 28.5 and 42.1 months while (6) shows periodicity around 4.3, 6.9, 10.3 and 18.1 months. We have found almost similar periods in the solar flares, sunspot data, solar proton data which indicates that the solar activity cycle may be due to the variable character of nuclear energy generation inside the sun.

Koushik Ghosh; Probhas Raychaudhuri

2006-06-05T23:59:59.000Z

119

Changes in the halo formation rates due to features in the primordial spectrum  

E-Print Network [OSTI]

Features in the primordial scalar power spectrum provide a possible roadway to describe the outliers at the low multipoles in the WMAP data. Apart from the CMB angular power spectrum, these features can also alter the matter power spectrum and, thereby, the formation of the large scale structure. Carrying out a complete numerical analysis, we investigate the effects of primordial features on the formation rates of the halos. We consider a few different inflationary models that lead to features in the scalar power spectrum and an improved fit to the CMB data, and analyze the corresponding imprints on the formation of halos. Performing a Markov Chain Monte Carlo analysis with the WMAP seven year data and the SDSS halo power spectrum from LRG DR7 for the models of our interest, we arrive at the parameter space of the models allowed by the data. We illustrate that, inflationary potentials, such as the quadratic potential with sinusoidal modulations and the axion monodromy model, which generate certain repeated, oscillatory features in the inflationary perturbation spectrum, do not induce a substantial difference in the number density of halos at their best fit values, when compared with, say, a nearly scale invariant spectrum as is generated by the standard quadratic potential. However, we find that the number density and the formation rates of halos change by about 13-22% for halo masses ranging over 10^4-10^14 solar mass, for potential parameters that lie within 2-sigma around the best fit values arrived at from the aforesaid joint constraints. We briefly discuss the implications of our results.

Dhiraj Kumar Hazra

2013-02-07T23:59:59.000Z

120

Injection Locking Techniques for Spectrum Analysis  

SciTech Connect (OSTI)

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

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

ALS Spectrum  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary)morphinanInformation Desert SouthwestTechnologies |November 2011Astudies smartHistory: The First 20ALSALS Spectrum

122

EFFECT OF DARK MATTER HALO SUBSTRUCTURES ON GALAXY ROTATION CURVES  

SciTech Connect (OSTI)

In this paper, the effect of halo substructures on galaxy rotation curves is investigated using a simple model of dark matter clustering. A dark matter halo density profile is developed based only on the scale-free nature of clustering that leads to a statistically self-similar distribution of the substructures at the galactic scale. A semi-analytical method is used to derive rotation curves for such a clumpy dark matter density profile. It is found that the halo substructures significantly affect the galaxy velocity field. Based on the fractal geometry of the halo, this self-consistent model predicts a Navarro-Frenk-White-like rotation curve and a scale-free power spectrum of the rotation velocity fluctuations.

Roy, Nirupam, E-mail: nroy@aoc.nrao.ed [NRAO, P.O. Box O, 1003 Lopezville Road, Socorro, NM 87801 (United States)

2010-11-01T23:59:59.000Z

123

Hints on the nature of dark matter from the properties of Milky Way satellites  

SciTech Connect (OSTI)

The nature of dark matter is still unknown and one of the most fundamental scientific mysteries. Although successfully describing large scales, the standard cold dark matter model (CDM) exhibits possible shortcomings on galactic and sub-galactic scales. It is exactly at these highly non-linear scales where strong astrophysical constraints can be set on the nature of the dark matter particle. While observations of the Lyman-? forest probe the matter power spectrum in the mildly non-linear regime, satellite galaxies of the Milky Way provide an excellent laboratory as a test of the underlying cosmology on much smaller scales. Here we present results from a set of high resolution simulations of a Milky Way sized dark matter halo in eight distinct cosmologies: CDM, warm dark matter (WDM) with a particle mass of 2 keV and six different cold plus warm dark matter (C+WDM) models, varying the fraction, f{sub wdm}, and the mass, m{sub wdm}, of the warm component. We used three different observational tests based on Milky Way satellite observations: the total satellite abundance, their radial distribution and their mass profile. We show that the requirement of simultaneously satisfying all three constraints sets very strong limits on the nature of dark matter. This shows the power of a multi-dimensional small scale approach in ruling out models which would be still allowed by large scale observations.

Anderhalden, Donnino; Diemand, Juerg [Institute for Theoretical Physics, University of Zürich, Winterthurerstrasse 190, 8057 Zürich (Switzerland); Schneider, Aurel [Department of Physics and Astronomy, University of Sussex, Brighton, BN1 9QH (United Kingdom); Macciò, Andrea V. [Max-Planck-Institute for Astronomy, Königstuhl 17, 69117 Heidelberg (Germany); Bertone, Gianfranco, E-mail: donninoa@physik.uzh.ch, E-mail: aurel.schneider@sussex.ac.uk, E-mail: maccio@mpia.de, E-mail: diemand@physik.uzh.ch, E-mail: gf.bertone@gmail.com [GRAPPA Institute, University of Amsterdam, Science Park 904, 1090 GL Amsterdam (Netherlands)

2013-03-01T23:59:59.000Z

124

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 (OSTI)

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

125

Shapes of dark matter halos  

E-Print Network [OSTI]

I present an analysis of the density shapes of dark matter halos in LCDM and LWDM cosmologies. The main results are derived from a statistical sample of galaxy-mass halos drawn from a high resolution LCDM N-body simulation. Halo shapes show significant trends with mass and redshift: low-mass halos are rounder than high mass halos, and, for a fixed mass, halos are rounder at low z. Contrary to previous expectations, which were based on cluster-mass halos and non-COBE normalized simulations, LCDM galaxy-mass halos at z=0 are not strongly flattened, with short to long axis ratios of s = 0.70 +/- 0.17. I go on to study how the shapes of individual halos change when going from a LCDM simulation to a simulation with a warm dark matter power spectrum (LWDM). Four halos were compared, and, on average, the WDM halos are more spherical than their CDM counterparts (s =0.77 compared to s = 0.71). A larger sample of objects will be needed to test whether the trend is significant.

James S. Bullock

2001-06-21T23:59:59.000Z

126

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

SciTech Connect (OSTI)

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

127

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

128

Gamma-ray probes of dark matter substructure  

SciTech Connect (OSTI)

The substructure content of dark matter halos is interesting because it can be affected by complex galaxy physics and dark matter particle physics. However, observing the small scale structure of dark matter is a challenge. The subhalo abundance (mass function, minimum mass) and morphology (density profile, subhalo shape, subsubstructure) contain information about complex astrophysics (halo formation processes) and new exotic fundamental physics (dark matter interactions). Indirect detection of dark matter annihilation radiation (DMAR) in gamma rays may be the most direct method for observing small scale structure. I outline the ways in which gamma rays may probe halo substructure. If substructure is bountiful, it may be responsible for the eventual discovery of DMAR, for instance in galaxy clusters or the diffuse gamma-ray background. Otherwise, the observation of DMAR in places without much substructure, such as the Galactic center, would lead to strict limits on the properties of small scale structure. Properties of the gamma-ray angular power spectrum will also provide information or constraints on Milky Way halo substructure.

Campbell, Sheldon [Department of Physics and Center for Cosmology and AstroParticle Physics (CCAPP), The Ohio State University, 191 W. Woodruff Ave., Columbus, OH 43210 (United States)

2014-06-24T23:59:59.000Z

129

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

SciTech Connect (OSTI)

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

130

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.

131

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. The inferred matter power spectrum is also found to be consistent with recent Lyman-$\\alpha$ forest data, which is in tension with the Planck-favored $\\Lambda$CDM model with power-law primordial power spectrum.

Quinn E. Minor; Manoj Kaplinghat

2015-03-08T23:59:59.000Z

132

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

133

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

134

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

135

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

136

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

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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...

137

Blue running of the primordial tensor spectrum  

E-Print Network [OSTI]

We examine the possibility of positive spectral index of the power spectrum of the primordial tensor perturbation produced during inflation in the light of the detection of the B-mode polarization by the BICEP2 collaboration. We find a blue tilt is in general possible when the slow-roll parameter decays rapidly. We present two known examples in which a positive spectral index for the tensor power spectrum can be obtained. We also briefly discuss other consistency tests for further studies on inflationary dynamics.

Jinn-Ouk Gong

2014-07-09T23:59:59.000Z

138

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

139

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

140

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

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

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

142

Two field matter bounce cosmology  

SciTech Connect (OSTI)

We re-examine the non-singular Matter Bounce scenario first developed in [20], which starts with a matter-dominated period of contraction and transitions into an Ekpyrotic phase of contraction. We consider both matter fields, the first of which plays the role of regular matter, and the second of which is responsible for the non-singular bounce. Since the dominant matter field is massive, the induced curvature fluctuations are initially not scale-invariant, whereas the fluctuations of the second scalar field (which are initially entropy fluctuations) are scale-invariant. We study the transfer of the initial entropy perturbations into curvature fluctuations in the matter-dominated phase of contraction and show that the latter become nearly scale invariant on large scales but are blue tilted on small scales. We study the evolution of both curvature and entropy fluctuations through the bounce, and show that both have a scale-invariant spectrum which is blue-tilted on small scales. However, we find that the entropy fluctuations have an amplitude that is much smaller than that of the curvature perturbations, due to gravitational amplification of curvature perturbations during the bounce phase.

Cai, Yi-Fu; McDonough, Evan; Duplessis, Francis; Brandenberger, Robert H., E-mail: yifucai@physics.mcgill.ca, E-mail: evanmc@physics.mcgill.ca, E-mail: francis.duplessis@mail.mcgill.ca, E-mail: rhb@hep.physics.mcgill.ca [Department of Physics, McGill University, Montréal, QC H3A 2T8 (Canada)

2013-10-01T23:59:59.000Z

143

Matter Field, Dark Matter and Dark Energy  

E-Print Network [OSTI]

A model concerning particle theory and cosmology is proposed. Matter field, dark matter and dark energy are created by an energy flow from space to primordial matter fields at the phase transition in the early universe.

Masayasu Tsuge

2009-03-24T23:59:59.000Z

144

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 (OSTI)

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

145

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 (OSTI)

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

146

Neutron Scattering: Condensed Matter and Magnetic Science, MPA...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Neutron Scattering Neutron Scattering Capability description: Neutron scattering is a powerful probe of structure and collective modes of condensed matter. We are focused on direct...

147

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.

148

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.

149

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

150

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

151

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.

152

Radio and Spectrum Management | Department of Energy  

Broader source: Energy.gov (indexed) [DOE]

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...

153

Quantized black holes, their spectrum and radiation  

SciTech Connect (OSTI)

Under quite natural general assumptions, the following results are obtained. The maximum entropy of a quantized surface is demonstrated to be proportional to the surface area in the classical limit. The general structure of the horizon spectrum is found. In the special case of loop quantum gravity, the value of the Barbero-Immirzi parameter is found. The discrete spectrum of thermal radiation of a black hole fits the Wien profile. The natural widths of the lines are much smaller than the distances between them. The total intensity of the thermal radiation is estimated. If the density of quantized primordial black holes is close to the present upper limit on the dark-matter density in our Solar system, the sensitivity of modern detectors is close to that necessary for detecting this radiation.

Khriplovich, I. B. [Budker Institute of Nuclear Physics (Russian Federation)], E-mail: khriplovich@inp.nsk.su

2008-04-15T23:59:59.000Z

154

A Narrower Spectrum for a Wider View of Matter  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May JunDatastreamsmmcrcalgovInstrumentsrucLasDelivered‰PNGExperience hands-onASTROPHYSICSHe β-Research andAFishing forAA

155

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

156

NREL Spectrum of Innovation  

ScienceCinema (OSTI)

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

2013-05-29T23:59:59.000Z

157

E-Print Network 3.0 - angular spectrum approach Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

(Contribution to the IUCAA annual report 2006-2007) Summary: ;Estimating the angular power spectrum of CMB The cosmological information that can be extracted from... in the...

158

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

159

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

160

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

2015-03-09T23:59:59.000Z

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

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 ...

Davis, Jonathan H

2014-01-01T23:59:59.000Z

162

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

163

FREQUENCY HOPPING SPREAD SPECTRUM DIRECT SEQUENCE SPREAD SPECTRUM  

E-Print Network [OSTI]

FREQUENCY HOPPING SPREAD SPECTRUM VS. DIRECT SEQUENCE SPREAD SPECTRUM RAYLINK AND RAYTHEON local-area network products, such as Raytheon's RaylinkTM products, use the frequency hopping method

Westall, James M.

164

Matter Wave Radiation Leading to Matter Teleportation  

E-Print Network [OSTI]

The concept of matter wave radiation is put forward, and its equation is established for the first time. The formalism solution shows that the probability density is a function of displacement and time. A free particle and a two-level system are reinvestigated considering the effect of matter wave radiation. Three feasible experimental designs, especially a modified Stern-Gerlach setup, are proposed to verify the existence of matter wave radiation. Matter wave radiation effect in relativity has been formulated in only a raw formulae, which offers another explanation of Lamb shift. A possible mechanics of matter teleportation is predicted due to the effect of matter wave radiation.

Yong-Yi Huang

2015-02-12T23:59:59.000Z

165

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

166

Baryonic matter and beyond  

E-Print Network [OSTI]

We summarize recent developments in identifying the ground state of dense baryonic matter and beyond. The topics include deconfinement from baryonic matter to quark matter, a diquark mixture, topological effect coupled with chirality and density, and inhomogeneous chiral condensates.

Kenji Fukushima

2014-10-01T23:59:59.000Z

167

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

168

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

169

Dark Matter Theory  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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)...

170

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

171

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

172

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

173

Velocity coordinate spectrum: geometrical aspects of observations  

E-Print Network [OSTI]

We analyze a technique of obtaining turbulence power spectrum using spectral line data along the velocity coordinate, which we refer to as Velocity Coordinate Spectrum (VCS). We formalize geometrical aspects of observation through a single factor, "geometric term". We find that all variety of particular observational configurations can be described using correspondent variants of this term, which we explicitly calculate. This allows us to obtain asymptotics for both parallel lines of sight and crossing lines of sight. The latter case is especially important for studies of turbulence within diffuse ISM in Milky Way. For verification of our results, we use direct calculation of VCS spectra, while the numerical simulations are presented in a companion paper.

A. Chepurnov; A. Lazarian

2007-01-31T23:59:59.000Z

174

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

175

Dark Matter: Early Considerations  

E-Print Network [OSTI]

A review of the study of dark matter is given, starting with earliest studies and finishing with the establishment of the standard Cold Dark Matter paradigm in mid 1980-s. Particular attention is given to the collision of the classical and new paradigms concerning the matter content of the Universe. Also the amount of baryonic matter, dark matter and dark energy is discussed using modern estimates.

J. Einasto

2004-01-16T23:59:59.000Z

176

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

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

white matter Search Powered by Explorit Topic List Advanced Search Sample search results for: altered white matter Page: << < 1 2 3 4 5 > >> 1 Prefrontal Fronto-Temporal Occipital...

177

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

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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...

178

E-Print Network 3.0 - automated white-matter tractography Sample...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

white-matter tractography Search Powered by Explorit Topic List Advanced Search Sample search results for: automated white-matter tractography Page: << < 1 2 3 4 5 > >> 1 An...

179

E-Print Network 3.0 - age-related white matter Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

white matter Search Powered by Explorit Topic List Advanced Search Sample search results for: age-related white matter Page: << < 1 2 3 4 5 > >> 1 Assessing Early Brain Development...

180

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

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

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

182

PINS Spectrum Identification Guide  

SciTech Connect (OSTI)

The Portable Isotopic Neutron Spectroscopy—PINS, for short—system identifies the chemicals inside munitions and containers without opening them, a decided safety advantage if the fill chemical is a hazardous substance like a chemical warfare agent or an explosive. The PINS Spectrum Identification Guide is intended as a reference for technical professionals responsible for the interpretation of PINS gamma-ray spectra. The guide is divided into two parts. The three chapters that constitute Part I cover the science and technology of PINS. Neutron activation analysis is the focus of Chapter 1. Chapter 2 explores PINS hardware, software, and related operational issues. Gamma-ray spectral analysis basics are introduced in Chapter 3. The six chapters of Part II cover the identification of PINS spectra in detail. Like the PINS decision tree logic, these chapters are organized by chemical element: phosphorus-based chemicals, chlorine-based chemicals, etc. These descriptions of hazardous, toxic, and/or explosive chemicals conclude with a chapter on the identification of the inert chemicals, e.g. sand, used to fill practice munitions.

A.J. Caffrey

2012-03-01T23:59:59.000Z

183

Design of programmable matter  

E-Print Network [OSTI]

Programmable matter is a proposed digital material having computation, sensing, actuation, and display as continuous properties active over its whole extent. Programmable matter would have many exciting applications, like ...

Knaian, Ara N. (Ara Nerses), 1977-

2008-01-01T23:59:59.000Z

184

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

185

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

SciTech Connect (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 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

186

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

187

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

188

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

189

Interference Characterization and Spectrum Sharing in Large Wireless Networks  

E-Print Network [OSTI]

SUs willing to utilize the spectrum band of the PU. The aggregate inter- ference power received fulfillment of the requirements for the degree of Doctor of Philosophy in Electrical and Computer Engineering Ottawa-Carleton Institute for Electrical and Computer Engineering (OCIECE) Department of Systems

Yanikomeroglu, Halim

190

The UV spectrum of nebulae  

E-Print Network [OSTI]

This paper presents an analysis of the UV spectrum of some nebulae with clearly identified illuminating stars, all observed by the IUE satellite. The data show remarkable properties of the UV spectrum of the nebulae. Each spectrum is the product of the star spectrum and a linear function of 1/lambda. There is no peculiar behaviour in the spectrums at 2200A: no bump created in the spectrum of a nebula and no excess of scattering. When moving away from the star, the surface brightness of a nebula decreases as the inverse of the square of the angular distance to the star. These results can logically be interpreted in terms of scattering of starlight. They imply constant properties of the interstellar grains in the UV and in the directions of space sampled by the nebulae, and probably a strong forward scattering phase function. There is no evidence for any particular type of grain which would specifically extinguish starlight at 2200A. Concerning the UV spectrum of a star, this may imply a revisal of the traditional interpretation of the 2200A bump.

F. Zagury

2001-06-18T23:59:59.000Z

191

Utilization and fairness in spectrum assignment for opportunistic spectrum access  

E-Print Network [OSTI]

985. [4] C AO , L. , AND Z HENG , H. Spectrum allocation in+ [26] Z HAO , J. , Z HENG , H. , AND Y ANG , G. Distributed2005, to appear). [27] Z HENG , H. , AND C AO , L. Device-

Peng, ChunYi; Zheng, Haitao; Zhao, Ben Y

2006-01-01T23:59:59.000Z

192

Of Matters Condensed  

E-Print Network [OSTI]

The American Physical Society (APS) March Meeting of condensed matter physics has grown to nearly 10,000 participants, comprises 23 individual APS groups, and even warrants its own hashtag (#apsmarch). Here we analyze the text and data from March Meeting abstracts of the past nine years and discuss trends in condensed matter physics over this time period. We find that in comparison to atomic, molecular, and optical physics, condensed matter changes rapidly, and that condensed matter appears to be moving increasingly toward subject matter that is traditionally in materials science and engineering.

Shulman, Michael

2015-01-01T23:59:59.000Z

193

Incompressibility of strange matter  

E-Print Network [OSTI]

Strange stars calculated from a realistic equation of state (EOS), that incorporate chiral symmetry restoration as well as deconfinement at high density show compact objects in the mass radius curve. We compare our calculations of incompressibility for this EOS with that of nuclear matter. One of the nuclear matter EOS has a continuous transition to ud-matter at about five times normal density. Another nuclear matter EOS incorporates density dependent coupling constants. From a look at the consequent velocity of sound, it is found that the transition to ud-matter seems necessary.

Monika Sinha; Manjari Bagchi; Jishnu Dey; Mira Dey; Subharthi Ray; Siddhartha Bhowmick

2004-04-01T23:59:59.000Z

194

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.

195

Visible Spectrum Incandescent Selective Emitter  

SciTech Connect (OSTI)

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

196

Stealth Dark Matter: Dark scalar baryons through the Higgs portal  

E-Print Network [OSTI]

We present a new model of "Stealth Dark Matter": a composite baryonic scalar of an $SU(N_D)$ strongly-coupled theory with even $N_D \\geq 4$. All mass scales are technically natural, and dark matter stability is automatic without imposing an additional discrete or global symmetry. Constituent fermions transform in vector-like representations of the electroweak group that permit both electroweak-breaking and electroweak-preserving mass terms. This gives a tunable coupling of stealth dark matter to the Higgs boson independent of the dark matter mass itself. We specialize to $SU(4)$, and investigate the constraints on the model from dark meson decay, electroweak precision measurements, basic collider limits, and spin-independent direct detection scattering through Higgs exchange. We exploit our earlier lattice simulations that determined the composite spectrum as well as the effective Higgs coupling of stealth dark matter in order to place bounds from direct detection, excluding constituent fermions with dominant...

Appelquist, Thomas; Buchoff, Michael I; Fleming, George T; Jin, Xiao-Yong; Kiskis, Joe; Kribs, Graham D; Neil, Ethan T; Osborn, James C; Rebbi, Claudio; Rinaldi, Enrico; Schaich, David; Schroeder, Chris; Syritsyn, Sergey; Vranas, Pavlos; Weinberg, Evan; Witzel, Oliver

2015-01-01T23:59:59.000Z

197

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

198

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

199

Broad-Spectrum Antiviral Therapeutics  

E-Print Network [OSTI]

Currently there are relatively few antiviral therapeutics, and most which do exist are highly pathogen-specific or have other disadvantages. We have developed a new broad-spectrum antiviral approach, dubbed Double-stranded ...

Rider, Todd H.

200

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 ...

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

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

202

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.

203

Spectrum Technology Workshop | Department of Energy  

Broader source: Energy.gov (indexed) [DOE]

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

204

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

205

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

206

Distance Spectrum Analysis of Third Generation Turbo Codes  

E-Print Network [OSTI]

Abstract: Turbo Codes are a class of powerful error correction codes that were introduced in 1993 by a group of researchers from France, which has the performance near the limit of Claude Shannon. After the introduction of turbo codes it has given raise a tremendous research work related to the new coding theory. This paper addresses the performance of Turbo codes by examining the codes ’ distance spectrum. It is well known that error floor occurs in the performance curve of turbo codes at moderate to high signal-to-noise ratio. The cause of error floor is due to the relatively low free distance of the codewords. Several techniques were proposed by researchers to lower the error floor. These techniques are assessed in this paper. To determine the free distance several algorithms were developed by different researchers. In this paper we used one of the recent algorithm to evaluate the distance spectrum of Turbo codes. We concentrate our analysis to measure and explain the distance spectrum of UMTS (Universal Mobile Telecommunication System), cdma2000 and CCSDS (Consultative Committee for Space Data Systems) standards Turbo Codes. It is shown that the distance spectrum depends on the code rate, interleaver size and the interleaver type.This distance spectrum of turbo codes can be used to estimate its performance at medium to higher SNR (signal to noise ratio). From our analysis we find out that the distance spectrum is one of the elementary issues using which one can find the optimum architecture of Turbo codes for specific application.

unknown authors

207

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

208

Matter: Space without Time  

E-Print Network [OSTI]

While Quantum Gravity remains elusive and Quantum Field Theory retains the interpretational difficulties of Quantum Mechanics, we have introduced an alternate approach to the unification of particles, fields, space and time, suggesting that the concept of matter as space without time provides a framework which unifies matter with spacetime and in which we anticipate the development of complete theories (ideally a single unified theory) describing observed 'particles, charges, fields and forces' solely with the geometry of our matter-space-time universe.

Yousef Ghazi-Tabatabai

2012-11-19T23:59:59.000Z

209

The acoustic spectrum of alpha Cen A  

E-Print Network [OSTI]

This paper presents the analysis of Doppler p-mode observations of the G2V star $\\alpha$ Cen A obtained with the spectrograph CORALIE in May 2001. Thirteen nights of observations have made it possible to collect 1850 radial velocity measurements with a standard deviation of about 1.5 m s$^{-1}$. Twenty-eight oscillation modes have been identified in the power spectrum between 1.8 and 2.9 mHz with amplitudes in the range 12 to 44 cm s$^{-1}$. The average large and small spacing are respectively equal to 105.5 and 5.6 $\\mu$Hz. A comparison with stellar models of $\\alpha$ Cen A is presented.

F. Bouchy; F. Carrier

2002-06-04T23:59:59.000Z

210

LyMAS: Predicting Large-Scale Lyman-alpha Forest Statistics from the Dark Matter Density Field  

E-Print Network [OSTI]

[abridged] We describe LyMAS (Ly-alpha Mass Association Scheme), a method of predicting clustering statistics in the Ly-alpha forest on large scales from moderate resolution simulations of the dark matter distribution, with calibration from high-resolution hydrodynamic simulations of smaller volumes. We use the "Horizon MareNostrum" simulation, a 50 Mpc/h comoving volume evolved with the adaptive mesh hydrodynamic code RAMSES, to compute the conditional probability distribution P(F_s|delta_s) of the transmitted flux F_s, smoothed (1-dimensionally) over the spectral resolution scale, on the dark matter density contrast delta_s, smoothed (3-dimensionally) over a similar scale. In this study we adopt the spectral resolution of the SDSS-III BOSS at z=2.5, and we find optimal results for a dark matter smoothing length sigma=0.3 Mpc/h (comoving). In extended form, LyMAS exactly reproduces both the 1-dimensional power spectrum and 1-point flux distribution of the hydro simulation spectra. Applied to the MareNostrum ...

Peirani, Sébastien; Colombi, Stéphane; Blaizot, Jérémy; Dubois, Yohan; Pichon, Christophe

2013-01-01T23:59:59.000Z

211

Status of the large-scale dark-matter axion search  

SciTech Connect (OSTI)

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

212

Thermal-spectrum recriticality energetics  

SciTech Connect (OSTI)

Large computer codes have been created in the past to predict the energy release in hypothetical core disruptive accidents (CDA), postulated to occur in liquid metal reactors (LMR). These codes, such as SIMMER, are highly specific to LMR designs. More recent attention has focused on thermal-spectrum criticality accidents, such as for fuel storage basins and waste tanks containing fissile material. This paper resents results from recent one-dimensional kinetics simulations, performed for a recriticality accident in a thermal spectrum. Reactivity insertion rates generally are smaller than in LMR CDAs, and the energetics generally are more benign. Parametric variation of input was performed, including reactivity insertion and initial temperature.

Schwinkendorf, K.N.

1993-12-01T23:59:59.000Z

213

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

214

Features and nongaussianity in the inflationary power spectrum  

E-Print Network [OSTI]

I summarize recent work on (1) constraining spike-like features in the cosmic microwave background and large scale structure; (2) nonstandard Friedmann equation in stabilized warped 6D brane cosmology, with applications to inflation; and (3) nonlocal inflation models, motivated by string theory, which can yield large nongaussian CMB fluctuations. Work in collaboration with N. Barnaby, T. Biswas, F. Chen, L. Hoi, G. Holder and S. Kanno.

James M. Cline

2008-05-14T23:59:59.000Z

215

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.

216

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

217

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

218

The Dark Matter problem  

E-Print Network [OSTI]

In these notes I will briefly summarize our knowledge about the dark matter problem, and emphasize the corresponding dynamical aspects. This covers a wide area of research, so I have been selective, and have concentrated on the subject of dark matter in nearby galaxies, in particular spirals.

A. Bosma

1998-12-01T23:59:59.000Z

219

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.

220

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

SciTech Connect (OSTI)

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

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

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

222

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

223

Relativistic nuclear matter in generalized thermo-statistics  

E-Print Network [OSTI]

nuclear medium. The correlation might lead to the power-law. 2) The baryon densities in Refs. [9,10] doRelativistic nuclear matter in generalized thermo-statistics K. Miyazaki E-mail: miyazakiro temperature are determined through the Gibbs thermodynamic relation. The power-law index is constrained

224

Cosmic-ray electron signatures of dark matter  

SciTech Connect (OSTI)

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

225

Gravitational waves from a curvaton model with blue spectrum  

SciTech Connect (OSTI)

We investigate the gravitational wave background induced by the first order scalar perturbations in the curvaton models. We consider the quadratic and axion-like curvaton potential which can generate the blue-tilted power spectrum of curvature perturbations on small scales and derive the maximal amount of gravitational wave background today. We find the power spectrum of the induced gravitational wave background has a characteristic peak at the frequency corresponding to the scale reentering the horizon at the curvaton decay, in the case where the curvaton does not dominate the energy density of the Universe. We also find the enhancement of the amount of the gravitational waves in the case where the curvaton dominates the energy density of the Universe. Such induced gravitational waves would be detectable by the future space-based gravitational wave detectors or pulsar timing observations.

Kawasaki, Masahiro; Kitajima, Naoya; Yokoyama, Shuichiro, E-mail: kawasaki@icrr.u-tokyo.ac.jp, E-mail: nk610@icrr.u-tokyo.ac.jp, E-mail: shu@icrr.u-tokyo.ac.jp [Institute for Cosmic Ray Research, University of Tokyo, Kashiwa, Chiba 277-8582 (Japan)

2013-08-01T23:59:59.000Z

226

Statistical Tools for Analyzing the Cosmic Ray Energy Spectrum  

E-Print Network [OSTI]

In this paper un-binned statistical tools for analyzing the cosmic ray energy spectrum are developed and illustrated with a simulated data set. The methods are designed to extract accurate and precise model parameter estimators in the presence of statistical and systematic energy errors. Two robust methods are used to test for the presence of flux suppression at the highest energies: the Tail-Power statistic and a likelihood ratio test. Both tests give evidence of flux suppression in the simulated data. The tools presented can be generalized for use on any astrophysical data set where the power-law assumption is relevant and can be used to aid observational design.

J. D. Hague; B. R. Becker; M. S. Gold; J. A. J. Matthews

2008-08-20T23:59:59.000Z

227

Post-WMAP Assessment of Infrared Cutoff in the Primordial Spectrum from Inflation  

E-Print Network [OSTI]

The recent Cosmic Microwave Background (CMB) measurements indicate that there is power deficiency of the CMB anisotropies at large scales compared with the $\\Lambda$CDM model. We have investigated the possibility of explaining such effects by a class of primordial power spectra which have infrared cutoffs close to the horizon scale. The primordial power spectrum recovered by direct deconvolution of the observed CMB angular spectrum indicates that the data prefers a sharp infrared cutoff with a localized excess (bump) just above the cutoff. We have been motivated to assess plausible extensions of simplest inflationary scenarios which readily accommodate similar form of infrared cutoff. We carry out a complete Bayesian analysis of the parameter space using {\\it Markov Chain Monte Carlo} technique with such a class of primordial power spectra. We show that primordial power spectrum that have features such as an infrared cutoff followed by a subsequent excess in power give better fit to the observed data compared to a nearly scale-invariant power law or power spectrum with just a monotonic infrared cutoff. However, there is substantial room for improvement in the match to data and calls for exploration of other mechanisms that may lead to infrared cutoff even closer to that recovered by direct deconvolution approach.

Rita Sinha; Tarun Souradeep

2006-08-11T23:59:59.000Z

228

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

229

Programmable matter by folding  

E-Print Network [OSTI]

Programmable matter is a material whose properties can be programmed to achieve specific shapes or stiffnesses upon command. This concept requires constituent elements to interact and rearrange intelligently in order to ...

Wood, R. J.

230

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

231

Matter & Energy Electronics  

E-Print Network [OSTI]

See also: Matter & Energy Electronics· Detectors· Technology· Construction· Sports Science Electronic Tongue Tastes Wine Variety, Vintage (Aug. 12, 2008) -- You don't need a wine expert to Advance

Suslick, Kenneth S.

232

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

233

Atomic dark matter  

SciTech Connect (OSTI)

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

234

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

235

Beurling spectrum of functions in Banach space  

E-Print Network [OSTI]

We are interested in Beurling spectrum of $\\mathbb X-$valued functions with application in functional delay differential equations.

Dang Vu Giang

2013-04-02T23:59:59.000Z

236

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

237

Adiabatic regularisation of power spectra in $k$-inflation  

E-Print Network [OSTI]

We look at the question posed by Parker {\\it et al.} about the effect of UV regularisation on the power spectrum for inflation. Focusing on the slow-roll $k$-inflation, we show that up to second order in the Hubble and sound flow parameters, the adiabatic regularisation of such model leads to no difference in the power spectrum apart from certain cases that violate near scale invariant power spectra. Furthermore, extending to non-minimal $k$-inflation, we establish the equivalence of the subtraction terms in the adiabatic regularisation of the power spectrum in Jordan and Einstein frames.

Allan L. Alinea; Takahiro Kubota; Yukari Nakanishi; Wade Naylor

2015-03-26T23:59:59.000Z

238

Adiabatic regularisation of power spectra in $k$-inflation  

E-Print Network [OSTI]

We look at the question posed by Parker {\\it et al.} about the effect of UV regularisation on the power spectrum for inflation. Focusing on the slow-roll $k$-inflation, we show that up to second order in the Hubble and sound flow parameters, the adiabatic regularisation of such model leads to no difference in the power spectrum apart from certain cases that violate near scale invariant power spectra. Furthermore, extending to non-minimal $k$-inflation, we establish the equivalence of the subtraction terms in the adiabatic regularisation of the power spectrum in Jordan and Einstein frames.

Alinea, Allan L; Nakanishi, Yukari; Naylor, Wade

2015-01-01T23:59:59.000Z

239

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

240

Energy Spectrum | Open Energy Information  

Open Energy Info (EERE)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home5b9fcbce19 NoPublic Utilities Address:011-DNA Jump37. It isInformation Contracts (ESPC) Webinar Jump to:S A Jump to:Spectrum

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.


241

466 IEEE TRANSACTIONS ON SPEECH AND AUDIO PROCESSING, VOL. 11, NO. 5, SEPTEMBER 2003 Noise Spectrum Estimation in Adverse Environments  

E-Print Network [OSTI]

--Noise spectrum estimation is a fundamental compo- nent of speech enhancement and speech recognition systems into a speech enhancement system achieves improved speech quality and lower residual noise. I. INTRODUCTION NOISE POWER spectrum estimation is a fundamental component of speech enhancement and speech recog

Cohen, Israel

242

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

E-Print Network [OSTI]

applications. Using dynamic spectrum access, each node's spectrum usage is inherently unpredictable. Experimental results show that the proposed approach can provide stable spectrum usage while improving its spectrum to each technology/network statically in peak-demand based long-term leases. Overtime, most

Almeroth, Kevin C.

243

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

244

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

245

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

246

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

2009-08-26T23:59:59.000Z

247

Electric power annual 1992  

SciTech Connect (OSTI)

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

248

Stealth Dark Matter: Dark scalar baryons through the Higgs portal  

E-Print Network [OSTI]

We present a new model of "Stealth Dark Matter": a composite baryonic scalar of an $SU(N_D)$ strongly-coupled theory with even $N_D \\geq 4$. All mass scales are technically natural, and dark matter stability is automatic without imposing an additional discrete or global symmetry. Constituent fermions transform in vector-like representations of the electroweak group that permit both electroweak-breaking and electroweak-preserving mass terms. This gives a tunable coupling of stealth dark matter to the Higgs boson independent of the dark matter mass itself. We specialize to $SU(4)$, and investigate the constraints on the model from dark meson decay, electroweak precision measurements, basic collider limits, and spin-independent direct detection scattering through Higgs exchange. We exploit our earlier lattice simulations that determined the composite spectrum as well as the effective Higgs coupling of stealth dark matter in order to place bounds from direct detection, excluding constituent fermions with dominantly electroweak-breaking masses. A lower bound on the dark baryon mass $m_B \\gtrsim 300$ GeV is obtained from the indirect requirement that the lightest dark meson not be observable at LEP II. We briefly survey some intriguing properties of stealth dark matter that are worthy of future study, including: collider studies of dark meson production and decay; indirect detection signals from annihilation; relic abundance estimates for both symmetric and asymmetric mechanisms; and direct detection through electromagnetic polarizability, a detailed study of which will appear in a companion paper.

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

2015-03-13T23:59:59.000Z

249

IONIZED OUTFLOWS FROM COMPACT STEEP SPECTRUM SOURCES  

SciTech Connect (OSTI)

Massive outflows are known to exist, in the form of extended emission-line regions (EELRs), around about one-third of powerful FR II radio sources. We investigate the origin of these EELRs by studying the emission-line regions around compact-steep-spectrum (CSS) radio galaxies that are younger (10{sup 3}-10{sup 5} yr old) versions of the FR II radio galaxies. We have searched for and analyzed the emission-line regions around 11 CSS sources by taking integral field spectra using Gemini Multi-Object Spectrograph on Gemini North. We fit the [O III] {lambda}5007 line and present the velocity maps for each detected emission-line region. We find, in most cases, that the emission-line regions have multi-component velocity structures with different velocity dispersions and/or flux distributions for each component. The velocity gradients of the emission-line gas are mostly well aligned with the radio axis, suggesting a direct causal link between the outflowing gas and the radio jets. The complex velocity structure may be a result of different driving mechanisms related to the onset of the radio jets. We also present the results from the line-ratio diagnostics we used to analyze the ionization mechanism of the extended gas, which supports the scenario where the emission-line regions are ionized by a combination of active galactic nucleus radiation and shock excitation.

Shih, Hsin-Yi; Stockton, Alan; Kewley, Lisa, E-mail: hsshih@ifa.hawaii.edu, E-mail: stockton@ifa.hawaii.edu, E-mail: lisa.kewley@anu.edu.au [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States)

2013-08-01T23:59:59.000Z

250

Closed String Thermodynamics and a Blue Tensor Spectrum  

E-Print Network [OSTI]

The BICEP-2 team has reported the detection of primordial cosmic microwave background B-mode polarization, with hints of a suppression of power at large angular scales relative to smaller scales. Provided that the B-mode polarization is due to primordial gravitational waves, this might imply a blue tilt of the primordial gravitational wave spectrum. Such a tilt would be incompatible with standard inflationary models, although it was predicted some years ago in the context of a mechanism that thermally generates the primordial perturbations through a Hagedorn phase of string cosmology. The purpose of this note is to encourage greater scrutiny of the data with priors informed by a model that is immediately falsifiable, but which \\textit{predicts} features that might be favoured by the data-- namely a blue tensor tilt with an induced and complimentary red tilt to the scalar spectrum, with a naturally large tensor to scalar ratio that relates to both.

Robert H. Brandenberger; Ali Nayeri; Subodh P. Patil

2014-03-26T23:59:59.000Z

251

SAW correlator spread spectrum receiver  

DOE Patents [OSTI]

A surface acoustic wave (SAW) correlator spread-spectrum (SS) receiver is disclosed which utilizes a first demodulation stage with a chip length n and a second demodulation stage with a chip length m to decode a transmitted SS signal having a code length l=n.times.m which can be very long (e.g. up to 2000 chips or more). The first demodulation stage utilizes a pair of SAW correlators which demodulate the SS signal to generate an appropriate code sequence at an intermediate frequency which can then be fed into the second demodulation stage which can be formed from another SAW correlator, or by a digital correlator. A compound SAW correlator comprising two input transducers and a single output transducer is also disclosed which can be used to form the SAW correlator SS receiver, or for use in processing long code length signals.

Brocato, Robert W

2014-04-01T23:59:59.000Z

252

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

253

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.

254

Matter & Energy Engineering  

E-Print Network [OSTI]

.com/products/seahawk/ Maryland Solar Panels-- Solar Installations from BGE HOME $0 Down For Big Energy Savings! www.bgehome.com/SolarLike 6 0 | More APA MLA See Also: Matter & Energy Petroleum Engineering Fossil Fuels Earth believe may be contributing to global warming. The UK government has just announced it is investing £1

Sóbester, András

255

Asymmetric condensed dark matter  

E-Print Network [OSTI]

We explore the viability of a boson dark matter candidate with an asymmetry between the number densities of particles and antiparticles. A simple thermal field theory analysis confirms that, under certain general conditions, this component would develop a Bose-Einstein condensate in the early universe that, for appropriate model parameters, could survive the ensuing cosmological evolution until now. The condensation of a dark matter component in equilibrium with the thermal plasma is a relativistic process, hence the amount of matter dictated by the charge asymmetry is complemented by a hot relic density frozen out at the time of decoupling. Contrary to the case of ordinary WIMPs, dark matter particles in a condensate can be very light, $10^{-22}\\,{\\rm eV} \\lesssim m \\lesssim 10^2\\,{\\rm eV}$; the lower limit arises from constraints on small-scale structure formation, while the upper bound ensures that the density from thermal relics is not too large. Big-Bang nucleosynthesis constrains the temperature of deco...

Aguirre, Anthony

2015-01-01T23:59:59.000Z

256

Dark matter axions `96  

SciTech Connect (OSTI)

This report discusses why axions have been postulated to exist, what cosmology implies about their presence as cold dark matter in the galactic halo, how axions might be detected in cavities wherein strong magnetic fields stimulate their conversion into photons, and relations between axions` energy spectra and galactic halos` properties.

Sikivie, P.

1996-12-31T23:59:59.000Z

257

The X-ray Spectrum of SAX J1808.4-3658  

E-Print Network [OSTI]

We report on the X-ray spectrum of the 401 Hz X-ray pulsar and type I burst source SAX J1808.4-3658, during its 1998 April/May hard outburst. The observations were made with RXTE over a period of three weeks. The spectrum is well-described by a power law with photon index 1.86+/-0.01 that is exponentially cut off at high energies. Excess soft emission above the power law is present as well as a weak Fe-K line. This is the first truly simultaneous broad-band (2.5-250 keV) spectrum of a type I burst source in the hard state. The spectrum is consistent with other hard state burster spectra which cover either only the soft (1-20 keV) or hard (>20 keV) bands, or cover both, but not simultaneously. The cut-off power law resembles black hole candidates (BHCs) in their low states, observed with RXTE. We compare the SAX J1808.4-3658 spectrum to three BHCs and find that the power law is somewhat softer. This suggests that the photon index may provide a way to distinguish between low state emission from Galactic black holes and type I bursters.

W. A. Heindl; D. M. Smith

1998-08-07T23:59:59.000Z

258

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.

259

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

260

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

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

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

262

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

263

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

264

Nonlinear cosmological power spectra in Einstein's gravity  

E-Print Network [OSTI]

Is Newton's gravity sufficient to handle the weakly nonlinear evolution stages of the cosmic large-scale structures? Here we resolve the issue by analytically deriving the density and velocity power spectra to the second order in the context of Einstein's gravity. The recently found pure general relativistic corrections appearing in the third-order perturbation contribute to power spectra to the second order. In this work the complete density and velocity power spectra to the second order are derived. The power transfers among different scales in the density power spectrum are estimated in the context of Einstein's gravity. The relativistic corrections in the density power spectrum are estimated to be smaller than the Newtonian one to the second order, but these could be larger than higher-order nonlinear Newtonian terms.

Hyerim Noh; Jai-chan Hwang

2008-05-13T23:59:59.000Z

265

Normal matter storage of antiprotons  

SciTech Connect (OSTI)

Various simple issues connected with the possible storage of anti p in relative proximity to normal matter are discussed. Although equilibrium storage looks to be impossible, condensed matter systems are sufficiently rich and controllable that nonequilibrium storage is well worth pursuing. Experiments to elucidate the anti p interactions with normal matter are suggested. 32 refs.

Campbell, L.J.

1987-01-01T23:59:59.000Z

266

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 Gravitation initial conditions beyond single-field slow roll #12;dark matter dark energy inflation NSF Site

Hu, Wayne

267

Dark Energy and Dark Matter  

E-Print Network [OSTI]

A brief overview of our current understanding of abundance and properties of dark energy and dark matter is presented. A more focused discussion of supersymmetric dark matter follows. Included is a frequentist approach to the supersymmetric parameter space and consequences for the direct detection of dark matter.

Keith A. Olive

2010-01-27T23:59:59.000Z

268

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.

269

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

270

Duopoly Competition in Dynamic Spectrum Leasing and Pricing  

E-Print Network [OSTI]

--Cognitive radio, spectrum trading, dynamic spectrum leasing, spectrum pricing, multistage dynamic game, subgame to share the spectrum with the licensed primary users. Various dynamic spectrum access mechanisms have been a spectrum owner dynamically transfers and trades the usage right of temporarily unused part of its licensed

Huang, Jianwei

271

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

272

Mixed axion-wino dark matter  

E-Print Network [OSTI]

A variety of supersymmetric models give rise to a split mass spectrum characterized by very heavy scalars but sub-TeV gauginos, usually with a wino-like LSP. Such models predict a thermally-produced underabundance of wino-like WIMP dark matter so that non-thermal DM production mechanisms are necessary. We examine the case where theories with a wino-like LSP are augmented by a Peccei-Quinn sector including an axion-axino-saxion supermultiplet in either the SUSY KSVZ or SUSY DFSZ models and with/without saxion decays to axions/axinos. We show allowed ranges of PQ breaking scale f_a for various cases which are generated by solving the necessary coupled Boltzmann equations. We also present results for a model with radiatively-driven naturalness but with a wino-like LSP.

Bae, Kyu Jung; Lessa, Andre; Serce, Hasan

2015-01-01T23:59:59.000Z

273

Hardening Neutron Spectrum for Advanced Actinides Transmutation Experiments in the ATR  

SciTech Connect (OSTI)

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

274

Constraining Decaying Dark Matter  

E-Print Network [OSTI]

We revisited the decaying dark matter (DDM) model, in which one collisionless particle decays early into two collisionless particles, that are potentially dark matter particles today. The effect of DDM will be manifested in the cosmic microwave background (CMB) and structure formation. With a systematic modification of CMB calculation tool \\texttt{camb}, we can numerically calculated this effect, and compare it to observations. Further Markov Chain Monte Carlo \\texttt{cosmomc} runnings update the constraints in that model: the free streaming length $\\lambda_{FS}\\lesssim0.5$Mpc for nonrelativistic decay, and $((M_{DDM}/keV) Y)^2 (T_d/yr)\\lesssim5\\times10^{-5}$ for relativistic decay.

Ran Huo

2011-07-13T23:59:59.000Z

275

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

276

Non-relativistic effective theory of dark matter direct detection  

SciTech Connect (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.

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

277

Weak Lensing: Dark Matter, Dark Energy  

SciTech Connect (OSTI)

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

278

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

279

NREL Spectrum of Clean Energy Innovation (Brochure)  

SciTech Connect (OSTI)

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

280

Distinct optical properties of relativistically degenerate matter  

SciTech Connect (OSTI)

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

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

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

282

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. 7 figs.

Fu, C.Y.

1998-11-24T23:59:59.000Z

283

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

284

Game Theoretic Analysis of Distributed Spectrum Sharing With Database Xu Chen and Jianwei Huang  

E-Print Network [OSTI]

licensed holders of TV spectrum) provide the database with the up-to-date information including TV tower transmission parameters and TV receiver protection requirements. Based on this information, the database location, given the white-space device's transmission parameters such as the transmission power. Although

Huang, Jianwei

285

Thermodynamics of electroweak matter  

E-Print Network [OSTI]

This paper is a slightly modified version of the introductory part of a PhD thesis, also containing the articles hep-ph/0303019, hep-ph/0510375 and hep-ph/0512177. We provide a short history of the research of electroweak thermodynamics and a brief introduction to the theory as well as to the necessary theoretical tools needed to work at finite temperatures. We then review computations regarding the pressure of electroweak matter at high temperatures (the full expression of the perturbative expansion of the pressure is given in the appendix) and the electroweak phase diagram at finite chemical potentials. Finally, we compare electroweak and QCD thermodynamics.

A. Gynther

2006-09-21T23:59:59.000Z

286

Discrete dark matter  

SciTech Connect (OSTI)

We propose a new motivation for the stability of dark matter (DM). We suggest that the same non-Abelian discrete flavor symmetry which accounts for the observed pattern of neutrino oscillations, spontaneously breaks to a Z{sub 2} subgroup which renders DM stable. The simplest scheme leads to a scalar doublet DM potentially detectable in nuclear recoil experiments, inverse neutrino mass hierarchy, hence a neutrinoless double beta decay rate accessible to upcoming searches, while {theta}{sub 13}=0 gives no CP violation in neutrino oscillations.

Hirsch, M.; Morisi, S.; Peinado, E.; Valle, J. W. F. [AHEP Group, Institut de Fisica Corpuscular--C.S.I.C./Universitat de Valencia, Edificio Institutos de Paterna, Apartado 22085, E-46071 Valencia (Spain)

2010-12-01T23:59:59.000Z

287

Materials/Condensed Matter  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May JunDatastreamsmmcrcalgovInstrumentsrucLas Conchas recovery challenge fund LasDubey selectedContractMaterials/Condensed Matter Print

288

Materials/Condensed Matter  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May JunDatastreamsmmcrcalgovInstrumentsrucLas Conchas recovery challenge fund LasDubey selectedContractMaterials/Condensed Matter

289

Initial Blackbeard power survey results  

SciTech Connect (OSTI)

The Blackbeard broadband VHF radio receiver is in low-earth orbit aboard the ALEXIS satellite. The receiver has been used to measure the transmitted power in four VHF bands (55.2-75.8, 28.0-94.8, 132.3-152.2, and 107.7-166.0 MHz) over quiet and noisy parts of the earth. The authors present the results of the survey and discuss their implications. They find that there are remote ocean areas over which the observed spectrum is largely free of man-made interference, but that the spectrum over most of the earth is dominated by broadcast VHF signals. The signal characteristics observed over a given area are quite constant when observed at different times of day and at intervals of several weeks to months. It appears that in many cases the bulk of the signal power is coming from a small number of sources.

Murphy, T.; Devenport, J.; Holden, D.

1996-06-01T23:59:59.000Z

290

Power supply  

DOE Patents [OSTI]

A modular, low weight impedance dropping power supply with battery backup is disclosed that can be connected to a high voltage AC source and provide electrical power at a lower voltage. The design can be scaled over a wide range of input voltages and over a wide range of output voltages and delivered power.

Yakymyshyn, Christopher Paul (Seminole, FL); Hamilton, Pamela Jane (Seminole, FL); Brubaker, Michael Allen (Loveland, CO)

2007-12-04T23:59:59.000Z

291

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

292

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

293

Energy-efficient distributed spectrum sensing with convex optimization  

E-Print Network [OSTI]

--We consider the problem of distributed spectrum sensing in cognitive radio networks with a central fusion the opportunistic use of such spectrum holes using cognitive radios in order to improve spectrum utilization [2], [3], [4]. A cognitive radio performs spectrum sensing in order to detect spectrum holes and avoids

Leus, Geert

294

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

295

Spectrum Investment with Uncertainty Based on Prospect Theory  

E-Print Network [OSTI]

A secondary operator in a cognitive radio network does not own any spectrum license, so it may acquire operator can either sense for the unused spectrum in a licensed band, or lease spectrum from a spectrum the unused spectrum in a licensed band, and use it to provide services to its users without causing any

Huang, Jianwei

296

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

297

Do high redshift quasars have powerful jets?  

E-Print Network [OSTI]

for the injection spectrum and surrounding gas profile (set [A] in Mocz et al (2011): the in- jection spectrum is given by a power-law index 2.14 and Lorentz factors ranging between 1 to 106; the surrounding density profile has a powerlaw index of 1.5). We assume... the galaxy hosts of quasars at z > 3 are com- pact (Szomoru et al 2013), and their group and cluster gas have more energy than is explainable by gravitational infall alone (Wu et al 2000; McCarthy et al 2012). Powerful jets are a considerable source of energy...

Fabian, A. C.; Walker, S. A.; Celotti, A.; Ghisellini, G.; Mocz, P.; Blundell, K. M.; McMahon, R. G.

2014-06-04T23:59:59.000Z

298

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

299

Statistical Mechanics of Jammed Matter  

E-Print Network [OSTI]

A thermodynamic formulation of jammed matter is reviewed. Experiments and simulations of compressed emulsions and granular materials are then used to provide a foundation for the thermodynamics.

Hernan A. Makse; Jasna Brujic; Sam F. Edwards

2005-03-03T23:59:59.000Z

300

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

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

Annihilation vs. decay: constraining dark matter properties from a gamma-ray detection  

SciTech Connect (OSTI)

Most proposed dark matter candidates are stable and are produced thermally in the early Universe. However, there is also the possibility of unstable (but long-lived) dark matter, produced thermally or otherwise. We propose a strategy to distinguish between dark matter annihilation and/or decay in the case that a clear signal is detected in gamma-ray observations of Milky Way dwarf spheroidal galaxies with gamma-ray experiments. The sole measurement of the energy spectrum of an indirect signal would render the discrimination between these cases impossible. We show that by examining the dependence of the intensity and energy spectrum on the angular distribution of the emission, the origin could be identified as decay, annihilation, or both. In addition, once the type of signal is established, we show how these measurements could help to extract information about the dark matter properties, including mass, annihilation cross section, lifetime, dominant annihilation and decay channels, and the presence of substructure. Although an application of the approach presented here would likely be feasible with current experiments only for very optimistic dark matter scenarios, the improved sensitivity of upcoming experiments could enable this technique to be used to study a wider range of dark matter models.

Palomares-Ruiz, Sergio [Centro de Física Teórica de Partículas, Instituto Superior Técnico, Av. Rovisco Pais 1, 1049-001 Lisboa (Portugal); Siegal-Gaskins, Jennifer M., E-mail: sergio.palomares.ruiz@ist.utl.pt, E-mail: jsg@mps.ohio-state.edu [Center for Cosmology and AstroParticle Physics, The Ohio State University, 191 W. Woodruff Ave., Columbus OH 43210 (United States)

2010-07-01T23:59:59.000Z

302

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

303

Decision Analysis of Dynamic Spectrum Access Rules  

SciTech Connect (OSTI)

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

304

Nucleons, Nuclear Matter and Quark Matter: A unified NJL approach  

SciTech Connect (OSTI)

We use an effective quark model to describe both hadronic matter and deconfined quark matter. By calculating the equations of state and the corresponding neutron star properties, we show that the internal properties of the nucleon have important implications for the properties of these systems.

S. Lawley; W. Bentz; A.W. Thomas

2006-02-10T23:59:59.000Z

305

Axion isocurvature fluctuations with extremely blue spectrum  

SciTech Connect (OSTI)

We construct an axion model for generating isocurvature fluctuations with blue spectrum, n{sub iso}=2-4, which is suggested by recent analyses of admixture of adiabatic and isocurvature perturbations with independent spectral indices, n{sub ad}{ne}n{sub iso}. The distinctive feature of the model is that the spectrum is blue at large scales while scale invariant at small scales. This is naturally realized by the dynamics of the Peccei-Quinn scalar field.

Kasuya, Shinta [Department of Information Science, Kanagawa University, Kanagawa 259-1293 (Japan); Kawasaki, Masahiro [Institute for Cosmic Ray Research, University of Tokyo, Chiba 277-8582 (Japan); Institute for the Physics and Mathematics of the Universe, University of Tokyo, Chiba 277-8582 (Japan)

2009-07-15T23:59:59.000Z

306

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

307

The vibrational Raman spectrum of CS?  

E-Print Network [OSTI]

THE VIBRATIONAL RAMAN SPECTRUM OF CSp A Thesis By HAROLD NOBLE BALLARD Approved as to style and content by Chairman o| Committee THE VIBRATIONAL RAMAN SPECTRUM OF CS2 HAROLD NOBLE BALLARD A Thesis Suhmitted to the Graduate School... in the procurement of necessary equipment. SECTION I: INTRODUCTION. SECTION II: CLASSICAL THEORY OF RAHAM SCATTERING . SECTION III: THEORY OF NORMAL VIBRATIONS AND VIBRATIONAL WAVE EQUATIONS. A, Morsel Vibrations B. Vibrational Wave Eqnation and lhergy Levels...

Ballard, Harold Noble

1950-01-01T23:59:59.000Z

308

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.

309

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

310

Orthogonal Technicolor with Isotriplet Dark Matter on the Lattice  

E-Print Network [OSTI]

We study the gauge dynamics of an SO(4)-gauge theory with two Dirac Wilson fermions transforming according to the vector representation of the gauge group. We determine the lattice phase diagram by locating the strong coupling bulk phase transition line and the zero PCAC mass line. We present results for the spectrum of the theory. In particular we measure the pseudoscalar, vector and axial meson masses. The data are consistent with a chiral symmetry breaking scenario rather than a conformal one. When used to break the electroweak symmetry dynamically the model leads to a natural dark matter candidate.

Ari Hietanen; Claudio Pica; Francesco Sannino; Ulrik Ishøj Søndergaard

2012-11-21T23:59:59.000Z

311

The Power of Efficiency: Why Momentum Savings Really Do Matter  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

dismiss Momentum Savings. After all, they can be difficult to understand and quantify in comparison to the direct (and well documented) savings from utility programs and...

312

The Power of Efficiency: Why Momentum Savings Really Do Matter  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear SecurityTensile Strain Switched Ferromagnetism in Layered NbS2 andThe MolecularPlace Where Emergency

313

Astronomical Evidence for Dark Matter  

E-Print Network [OSTI]

weapon in "Quake 4" is the Dark Matter Gun. In Futurama they use dark matter fuel, where "one pound is 10 of dynamics: #12;Galaxy Clusters Also with Sunyaev-Zel'dovich Effect. Inverse Compton scattering Sensitive to baryons Spectral distortion: Line of sight integral of pressure #12;Galaxy Clusters SZ Effect Compute

Golwala, Sunil

314

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.

315

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

316

Charmonium mass in nuclear matter  

E-Print Network [OSTI]

The mass shift of charmonium states in nuclear matter is studied in the perturbative QCD approach. The leading-order effect due to the change of gluon condensate in nuclear matter is evaluated using the leading-order QCD formula, while the higher...

Lee, S. H.; Ko, Che Ming.

2003-01-01T23:59:59.000Z

317

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

SciTech Connect (OSTI)

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

318

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...

319

BINGO: A code for the efficient computation of the scalar bi-spectrum  

E-Print Network [OSTI]

We present a new and accurate Fortran code, the BI-spectra and Non-Gaussianity Operator (BINGO), for the efficient numerical computation of the scalar bi-spectrum and the non-Gaussianity parameter f_{NL} in single field inflationary models involving the canonical scalar field. The code can calculate all the different contributions to the bi-spectrum and the parameter f_{NL} for an arbitrary triangular configuration of the wavevectors. Focusing firstly on the equilateral limit, we illustrate the accuracy of BINGO by comparing the results from the code with the spectral dependence of the bi-spectrum expected in power law inflation. Then, considering an arbitrary triangular configuration, we contrast the numerical results with the analytical expression available in the slow roll limit, for, say, the case of the conventional quadratic potential. Considering a non-trivial scenario involving deviations from slow roll, we compare the results from the code with the analytical results that have recently been obtained in the case of the Starobinsky model in the equilateral limit. As an immediate application, we utilize BINGO to examine of the power of the non-Gaussianity parameter f_{NL} to discriminate between various inflationary models that admit departures from slow roll and lead to similar features in the scalar power spectrum. We close with a summary and discussion on the implications of the results we obtain.

Dhiraj Kumar Hazra; L. Sriramkumar; Jerome Martin

2013-05-18T23:59:59.000Z

320

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

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

Power LCAT  

SciTech Connect (OSTI)

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

322

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

323

Energy Matters: Industrial Energy Efficiency | Department of...  

Broader source: Energy.gov (indexed) [DOE]

Matters: Industrial Energy Efficiency Energy Matters: Industrial Energy Efficiency November 18, 2011 - 2:33pm Addthis On November 16, 2011, Deputy Assistant Secretary for Energy...

324

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

325

Dynamic Spectrum Management for Green DSL  

E-Print Network [OSTI]

to a power-rate-complexity trade-off. EDICS: SPC-TDLS Telephone networks and digital subscriber loops SPC

326

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

327

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

328

Analytical energy spectrum for hybrid mechanical systems  

E-Print Network [OSTI]

We investigate the energy spectrum for hybrid mechanical systems described by non-parity-symmetric quantum Rabi models. A set of analytical solutions in terms of the confluent Heun functions and their analytical energy spectrum are obtained. The analytical energy spectrum includes regular and exceptional parts, which are both confirmed by direct numerical simulation. The regular part is determined by the zeros of the Wronskian for a pair of analytical solutions. The exceptional part is relevant to the isolated exact solutions and its energy eigenvalues are obtained by analyzing the truncation conditions for the confluent Heun functions. By analyzing the energy eigenvalues for exceptional points, we obtain the analytical conditions for the energy-level-crossings, which correspond to two-fold energy degeneracy.

Honghua Zhong; Qiongtao Xie; Xiwen Guan; Murray T. Batchelor; Kelin Gao; Chaohong Lee

2013-11-07T23:59:59.000Z

329

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

330

The Unification and Cogeneration of Dark Matter and Baryonic Matter  

E-Print Network [OSTI]

In grand unified theories with gauge groups larger than SU(5), the multiplets that contain the known quarks and leptons also contain fermions that are singlets under the Standard Model gauge group. Some of these could be the dark matter of the universe. Grand unified theories can also have accidental U(1) global symmetries (analogous to B-L in minimal SU(5)) that can stabilize dark matter. These ideas are illustrated in an SU(6) model.

S. M. Barr

2011-09-18T23:59:59.000Z

331

The Unification and Cogeneration of Dark Matter and Baryonic Matter  

E-Print Network [OSTI]

In grand unified theories with gauge groups larger than SU(5), the multiplets that contain the known quarks and leptons also contain fermions that are singlets under the Standard Model gauge group. Some of these could be the dark matter of the universe. Grand unified theories can also have accidental U(1) global symmetries (analogous to B-L in minimal SU(5)) that can stabilize dark matter. These ideas are illustrated in an SU(6) model.

Barr, S M

2011-01-01T23:59:59.000Z

332

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

333

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

334

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

335

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.

336

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"

337

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

338

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

339

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

340

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

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

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

342

Climate Change, Nuclear Power and Nuclear  

E-Print Network [OSTI]

Climate Change, Nuclear Power and Nuclear Proliferation: Magnitude Matters Rob Goldston MIT IAP plays a large role in replacing coal red plants. al hydro electricity options penetrate in the climate way across scenarios, showing a slight severe climate targets. In Industry, the climate target has

343

Distribution and Structure of Matter in and around Galaxies  

E-Print Network [OSTI]

Understanding the origins and distribution of matter in the Universe is one of the most important quests in physics and astronomy. Themes range from astro-particle physics to chemical evolution in the Galaxy to cosmic nucleosynthesis and chemistry in an anticipation of a full account of matter in the Universe. Studies of chemical evolution in the early Universe will answer questions about when and where the majority of metals were formed, how they spread and why they appar today as they are. The evolution of matter in our Universe cannot be characterized as a simple path of development. In fact the state of matter today tells us that mass and matter is under constant reformation through on-going star formation, nucleosynthesis and mass loss on stellar and galactic scales. X-ray absorption studies have evolved in recent years into powerful means to probe the various phases of interstellar and intergalactic media. Future observatories such as IXO and Gen-X will provide vast new opportunities to study structure ...

Schulz, Norbert S; Bautz, Mark W; Canizares, Claude C; Davis, John; Dewey, Dan; Huenemoerder, David P; Heilmann, Ralf; Houck, John; Marshall, Herman L; Nowak, Mike; Schattenburg, Mark; Bregman, Joel; Diaz-Trigo, Maria; Fang, Taotao; Gagne, Marc; Kallman, Tim; Lautenegger, Maurice; Lee, Julia; Miller, Jon; Mukai, Koji; Parerels, Frits; Pollock, Andy; Rasmussen, Andy; Raymond, John; Smith, Randall; Yao, Yangsen

2009-01-01T23:59:59.000Z

344

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

345

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

346

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

347

Tailoring the Neutron Spectrum from a 14-MeV Neutron Generator to Approximate a Spontaneous-Fission Spectrum  

SciTech Connect (OSTI)

Many applications of neutrons for non-invasive measurements began with isotopic sources such as AmBe or Cf-252. Political factors have rendered AmBe undesirable in the United States and other countries, and the supply of Cf-252 is limited and significantly increasing in price every few years. Compact and low-power deuterium-tritium (DT) electronic neutron generators can often provide sufficient flux, but the 14-MeV neutron spectrum is much more energetic (harder) than an isotopic neutron source. A series of MCNP simulations were run to examine the extent to which the 14-MeV DT neutron spectrum could be softened through the use of high-Z and low-Z materials. Some potential concepts of operation require a portable neutron generator system, so the additional weight of extra materials is also a trade-off parameter. Using a reference distance of 30 cm from the source, the average neutron energy can be lowered to be less than that of either AmBe or Cf-252, while obtaining an increase in flux at the reference distance compared to a bare neutron generator. This paper discusses the types and amounts of materials used, the resulting neutron spectra, neutron flux levels, and associated photon production.

James Simpson; David Chichester

2011-06-01T23:59:59.000Z

348

Physical Protection of Classified Matter  

Broader source: Directives, Delegations, and Requirements [Office of Management (MA)]

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

349

Reducing cosmological small scale structure via a large dark matter-neutrino interaction: constraints and consequences  

E-Print Network [OSTI]

Cold dark matter explains a wide range of data on cosmological scales. However, there has been a steady accumulation of evidence for discrepancies between simulations and observations at scales smaller than galaxy clusters. Solutions to these small scale structure problems may indicate that simulations need to improve how they include feedback from baryonic matter, or may imply that dark matter properties differ from the standard cold, noninteracting scenario. One promising way to affect structure formation on small scales is a relatively strong coupling of dark matter to neutrinos. We construct an experimentally viable, simple, renormalizable, model with new interactions between neutrinos and dark matter. We show that addressing the small scale structure problems requires dark matter with a mass that is tens of MeV, and a present-day density determined by an initial particle-antiparticle asymmetry in the dark sector. Generating a sufficiently large dark matter-neutrino coupling requires a new heavy neutrino with a mass around 100 MeV. The heavy neutrino is mostly sterile but has a substantial $\\tau$ neutrino component, while the three nearly massless neutrinos are partly sterile. We provide the first discussion of how such dark matter-neutrino interactions affect neutrino (especially $\\tau$ neutrino) phenomenology. This model can be tested by future astrophysical, particle physics, and neutrino oscillation data. A feature in the neutrino energy spectrum and flavor content from a future nearby supernova would provide strong evidence of neutrino-dark matter interactions. Promising signatures include anomalous matter effects in neutrino oscillations due to nonstandard interactions and a component of the $\\tau$ neutrino with mass around 100 MeV.

Bridget Bertoni; Seyda Ipek; David McKeen; Ann E. Nelson

2014-12-09T23:59:59.000Z

350

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

351

Power Recovery  

E-Print Network [OSTI]

.POWER RECOVERY Fletcher Mlirray Monsanto Chemical Company AB5'-:::0 p.p., will ??vi.w 'h. '.ohnnln,y nf 'h.::v,n. T:X:~~T ~ methods for estimating the power recovery potential from fluid streams. The ideal gas law formula for expanding gases.... Gas Law Estimation Power recovery estimates from a vapor stream can be made using the formula: which is derived from the Ideal Gas Law. At first glance the. formula seems imposing and perhaps difficult to occasionally use. If however; the formula...

Murray, F.

352

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

353

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

354

?CDM cosmology from matter only  

E-Print Network [OSTI]

I discuss a matter-only interpretation of {\\Lambda}CDM cosmology, based on conservation of energy and assuming a Machian definition of inertia. {\\Lambda}CDM cosmology can be linked to a Newtonian cosmic potential, subject to a propagating gravitational horizon. In a matter-only universe where total energy is conserved, Machian inertia related to the evolving potential may cause both deceleration and acceleration of recession.

Herman Telkamp

2015-04-08T23:59:59.000Z

355

The Cold Dark Matter Search test stand warm electronics card  

SciTech Connect (OSTI)

A card which does the signal processing for four SQUID amplifiers and two charge sensitive channels is described. The card performs the same functions as is presently done with two custom 9U x 280mm Eurocard modules, a commercial multi-channel VME digitizer, a PCI to GPIB interface, a PCI to VME interface and a custom built linear power supply. By integrating these functions onto a single card and using the power over Ethernet standard, the infrastructure requirements for instrumenting a Cold Dark Matter Search (CDMS) detector test stand are significantly reduced.

Hines, Bruce; /Colorado U., Denver; Hansen, Sten; /Fermilab; Huber, Martin; /Colorado U., Denver; Kiper, Terry; /Fermilab; Rau, Wolfgang; /Queen's U., Kingston; Saab, Tarek; /Florida U.; Seitz, Dennis; Sundqvist, Kyle; /UC, Berkeley; Mandic, Vuk; /Minnesota U.

2010-11-01T23:59:59.000Z

356

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.

357

Adaptive, full-spectrum solar energy system  

DOE Patents [OSTI]

An adaptive full spectrum solar energy system having at least one hybrid solar concentrator, at least one hybrid luminaire, at least one hybrid photobioreactor, and a light distribution system operably connected to each hybrid solar concentrator, each hybrid luminaire, and each hybrid photobioreactor. A lighting control system operates each component.

Muhs, Jeffrey D.; Earl, Dennis D.

2003-08-05T23:59:59.000Z

358

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

359

Green Wireless Cognition: Future Efficient Spectrum Sharing  

E-Print Network [OSTI]

Underwater Vehicles The project aims to develop an unmanned fully autonomous under water vehicles (UWV Spectrum Wireless Sensor in Underwater Networks * Bell's Law of Computer Classes formulated by Gordon Bell the challenges of underwater communications by an integration of sensor and multihop networks. Human

Shihada, Basem

360

Power combiner  

DOE Patents [OSTI]

A power combiner for the combining of symmetric and asymmetric traveling wave energy comprises a feed waveguide having an input port and a launching port, a reflector for reflecting launched wave energy, and a final waveguide for the collection and transport of launched wave energy. The power combiner has a launching port for symmetrical waves which comprises a cylindrical section coaxial to the feed waveguide, and a launching port for asymmetric waves which comprises a sawtooth rotated about a central axis.

Arnold, Mobius; Ives, Robert Lawrence

2006-09-05T23:59:59.000Z

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.


361

Gravitational Wave Spectrums from Pole-like Inflations based on Generalized Gravity Theories  

E-Print Network [OSTI]

We present a general and unified formulation which can handle the classical evolution and quantum generation processes of the cosmological gravitational wave in a broad class of generalized gravity theories. Applications are made in several inflation models based on the scalar-tensor theory, the induced gravity, and the low energy effective action of string theory. The gravitational wave power spectrums based on the vacuum expectation value of the quantized fluctuating metric during the pole-like inflation stages are derived in analytic forms. Assuming that the gravity theory transits to Einstein one while the relevant scales remain in the superhorizon scale, we derive the consequent power spectrums and the directional fluctuations of the relic radiation produced by the gravitational wave. The spectrums seeded by the vacuum fluctuations in the pole-like inflation models based on the generalized gravity show a distinguished common feature which differs from the scale invariant spectrum generated in an exponential inflation in Einstein gravity which is supported by observations.

J. Hwang

1997-10-10T23:59:59.000Z

362

Red and blue tilted tensor spectrum from Gibbons-Hawking temperature  

E-Print Network [OSTI]

The scale invariant scalar and tensor perturbations, which are predicted from inflation, are eigenmodes in the conformal coordinates. The 'out' observer in the de Sitter space observes a thermal spectrum with a Gibbons-Hawking temperature $H/2\\pi$ of these 'Bunch-Davies' particles. The tensor power spectrum observed in experiments can have an imprint of the Gibbons-Hawking thermal distribution due to the mode mixing between 'in' state conformal coordinates and the coordinate frame of the observer. We find that the the Bunch-Davies modes appear as thermal modes to the asymptotic Minkowski observer in the future and the power spectrum of the gravitational waves is blue-tilted with a spectral index $n_T \\sim 1$ even in the standard slow-roll inflation. On the other hand if the coordinate frame of the observer is taken to be static coordinates, the tensor spectrum is red-tilted with $n_T\\sim -1$. A likelihood analysis shows and find the best fit values of the slow-roll parameters for both cases. We find that the blue-tilted tensor gives a better fit and reconciles the PLANCK upper bound on the tensor-to-scalar ratio, $r <0.11$ with BICEP2 measurement of $r=0.2$. This supports the idea of particle production due to the mode mixing between the initial Bunch-Davies vacuum modes and the asymptotic Minkowski vacuum of the post-inflation universe.

Subhendra Mohanty; Akhilesh Nautiyal

2015-01-09T23:59:59.000Z

363

Power spectra of outflow-driven turbulence  

E-Print Network [OSTI]

We investigate the power spectra of outflow-driven turbulence through high-resolution three-dimensional isothermal numerical simulations where the turbulence is driven locally in real-space by a simple spherical outflow model. The resulting turbulent flow saturates at an average Mach number of ~2.5 and is analysed through density and velocity power spectra, including an investigation of the evolution of the solenoidal and compressional components. We obtain a shallow density power spectrum with a slope of ~-1.2 attributed to the presence of a network of localised dense filamentary structures formed by strong shock interactions. The total velocity power spectrum slope is found to be ~-2.0, representative of Burgers shock dominated turbulence model. The density weighted velocity power spectrum slope is measured as ~-1.6, slightly less than the expected Kolmogorov scaling value (slope of -5/3) found in previous works. The discrepancy may be caused by the nature of our real space driving model and we suggest ther...

Moraghan, Anthony; Yoon, Suk-Jin

2015-01-01T23:59:59.000Z

364

Cleco Power- Power Miser New Home Program  

Broader source: Energy.gov [DOE]

Louisiana's Cleco Power offers energy efficiency incentives to eligible customers. Cleco Power offers a rate discount for residential customers building homes that meet the Power Miser Program...

365

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

SciTech Connect (OSTI)

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

366

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

367

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

368

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

369

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

370

Perturbed Power-law parameters from WMAP7  

E-Print Network [OSTI]

We present a perturbative approach for studying inflation models with soft departures from scale free spectra of the power law model. In the perturbed power law (PPL) approach one obtains at the leading order both the scalar and tensor power spectra with the running of their spectral indices, in contrast to the widely used slow roll expansion. The PPL spectrum is confronted data and we show that the PPL parameters are well estimated from WMAP-7 data.

Minu Joy; Tarun Souradeep

2010-11-19T23:59:59.000Z

371

Perturbed Power-law parameters from WMAP7  

E-Print Network [OSTI]

We present a perturbative approach for studying inflation models with soft departures from scale free spectra of the power law model. In the perturbed power law (PPL) approach one obtains at the leading order both the scalar and tensor power spectra with the running of their spectral indices, in contrast to the widely used slow roll expansion. The PPL spectrum is confronted data and we show that the PPL parameters are well estimated from WMAP-7 data.

Joy, Minu

2010-01-01T23:59:59.000Z

372

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

373

Power Projects  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear Security Administration the1 - September 2006PhotovoltaicSeptember 22,ReactorAbout Power > FinancialPower

374

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

375

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

376

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

377

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

378

Star Power  

SciTech Connect (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

2014-10-17T23:59:59.000Z

379

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

380

Dressed-state approach to matter-wave mixing of bosons  

SciTech Connect (OSTI)

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

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

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

382

Enhancing spectrum utilization through cooperation and cognition in wireless systems  

E-Print Network [OSTI]

We have seen a proliferation of wireless technologies and devices in recent years. The resulting explosion of wireless demand has put immense pressure on available spectrum. Improving spectrum utilization is therefore ...

Rahul, Hariharan Shankar, 1975-

2013-01-01T23:59:59.000Z

383

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

384

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

385

Explaining Low Energy ?-ray Excess from the Galactic Centre using a Two Component Dark Matter Model  

E-Print Network [OSTI]

Over the past few years, there has been a hint of the $\\gamma$-ray excess observed by the Fermi-LAT satellite borne telescope from the region surrounding the Galactic Centre at an energy range $\\sim 1$-$3$ GeV. The nature of this excess $\\gamma$-ray spectrum is found to be consistent with the $\\gamma$-ray emission expected from dark matter annihilation at the Galactic Centre while disfavouring other known astrophysical sources as the possible origin of this phenomena. It is also reported that the spectrum and morphology of this excess $\\gamma$-rays can well be explained by the dark matter particles having mass in the range $30\\sim 40$ GeV annihilating into ${\\rm b}$ $\\bar{\\rm b}$ final state with an annihilation cross section ${\\sigma {\\rm v}} \\sim 1.4 - 2.0\\times10^{-26}$ cm$^3/$s at the Galactic centre. In this work, we propose a two component dark matter model where two different types of dark matter particles namely a complex scalar and a Dirac fermion are considered. The stability of both the dark sector particles are maintained by virtue of an additional local U$(1)_{\\rm X}$ gauge symmetry. We find that our proposed scenario can provide a viable explanation besides satisfying all the existing relevant theoretical, experimental and observational bounds.

Anirban Biswas

2014-12-04T23:59:59.000Z

386

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

387

Modern Cosmological Models with Dark Matter and Their Confrontation with Observational Data  

E-Print Network [OSTI]

New systematic classification of cosmological models of the present Universe is introduced. After making the comparison of these models with all existing observational data three viable models remain: the cold dark matter model with the cosmological constant (which becomes the most reasonable one if the Hubble constant $H_0>60$ km/s/Mpc); the mixed cold-hot dark matter model (models with two and especially three types of neutrinos with equal masses are in a slightly better agreement with observational data than the model with one massive neutrino); the pure cold dark matter model with a step-like initial spectrum of perturbations. The two latter models require $H_0\\leq 60$ km/s/Mpc.

A. A. Starobinsky

1996-03-15T23:59:59.000Z

388

Constraints on decaying dark matter from Fermi observations of nearby galaxies and clusters  

SciTech Connect (OSTI)

We analyze the impact of Fermi gamma-ray observations (primarily non-detections) of selected nearby galaxies, including dwarf spheroidals, and of clusters of galaxies on decaying dark matter models. We show that the fact that galaxy clusters do not shine in gamma rays puts the most stringent limits available to-date on the lifetime of dark matter particles for a wide range of particle masses and decay final states. In particular, our results put strong constraints on the possibility of ascribing to decaying dark matter both the increasing positron fraction reported by PAMELA and the high-energy feature in the electron-positron spectrum measured by Fermi. Observations of nearby dwarf galaxies and of the Andromeda Galaxy (M31) do not provide as strong limits as those from galaxy clusters, while still improving on previous constraints in some cases.

Dugger, Leanna; Profumo, Stefano [Department of Astronomy and Department of Physics, University of California Berkeley, 601 Campbell Hall, Berkeley, CA (United States); Jeltema, Tesla E., E-mail: greentee01@gmail.com, E-mail: tesla@ucolick.org, E-mail: profumo@scipp.ucsc.edu [UCO/Lick Observatories, 1156 High St., Santa Cruz, CA 95064 (United States)

2010-12-01T23:59:59.000Z

389

Dark matter from the scalar sector of 3-3-1 models without exotic electric charges  

E-Print Network [OSTI]

We show that three SU(2) singlet neutral scalars (two CP-even and one CP-odd) in the spectrum of models based on the gauge symmetry SU(3)_c X SU(3)_L X U(1)_X, which do not contain exotic electric charges, are realistic candidates for thermally generated self-interacting dark matter in the Universe, a type of dark matter that has been recently proposed in order to overcome some difficulties of collisionless cold dark matter models at the galactic scale. These candidates arise without introducing a new mass scale in the model and/or without the need for a discrete symmetry to stabilize them, but at the expense of tuning several combinations of parameters of the scalar potential.

Simonetta Filippi; William A. Ponce; Luis A. Sanchez

2005-10-27T23:59:59.000Z

390

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

391

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

392

HEALTH MATTERS Copper T IUD  

E-Print Network [OSTI]

HEALTH MATTERS Copper T IUD What is the Copper T IUD? The Copper T IUD is one of two types of intrauterine devices available in the United States. The Copper T IUD is a small, flexible device made of soft plastic and copper. It is easily and quickly inserted into the uterus by a health care provider to prevent

Yener, Aylin

393

Laser Cooling of Matter INTRODUCTION  

E-Print Network [OSTI]

- velopment of techniques that have allowed the ion motion to be cooled into the ground state of the confiningLaser Cooling of Matter INTRODUCTION Laser cooling of neutral atoms in the past decades has been a breakthrough in the understanding of their dy- namics and led to the seminal proposals of laser cooling

Kaiser, Robin

394

KALMAN FILTER WITH PHASE SPECTRUM COMPENSATION ALGORITHM FOR SPEECH ENHANCEMENT  

E-Print Network [OSTI]

KALMAN FILTER WITH PHASE SPECTRUM COMPENSATION ALGORITHM FOR SPEECH ENHANCEMENT Stephen So, Kamil K with a recent speech enhancement technique, called the phase spectrum compen- sation procedure, or PSC. More-- Kalman filter, phase spectrum compensation (PSC), speech enhancement 1. INTRODUCTION The Kalman filter

395

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

396

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

397

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.

398

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

399

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

400

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

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

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

402

Binary Consensus for Cooperative Spectrum Sensing in Cognitive Radio Networks  

E-Print Network [OSTI]

Binary Consensus for Cooperative Spectrum Sensing in Cognitive Radio Networks Shwan Ashrafi, Cooperative Spectrum Sensing. I. INTRODUCTION Cognitive Radio (CR), introduced by Mitola [1], is expected). As such, cognitive radio emerged as a possible solution by trying to use the spectrum holes and thus

Mostofi, Yasamin

403

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

404

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.

405

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

406

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

407

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

408

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

409

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

410

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

411

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

412

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.

413

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

414

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

415

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

416

Why Geology Matters: Decoding the Past, Anticipating the Future  

E-Print Network [OSTI]

Review: Why Geology Matters: Decoding the Past, AnticipatingUSA Macdougall, Doug. Why Geology Matters: Decoding theE-book available. Why Geology Matters pursues two goals: to

Anderson, Byron P.

2011-01-01T23:59:59.000Z

417

Energy Matters: Our Energy Independence | Department of Energy  

Broader source: Energy.gov (indexed) [DOE]

Matters: Our Energy Independence Energy Matters: Our Energy Independence Addthis Description In this installment of the livechat series "Energy Matters," Dr. Arun Majumdar takes...

418

Dynamical insight into dark-matter haloes  

E-Print Network [OSTI]

We investigate, using the spherical Jeans equation, self-gravitating dynamical equilibria satisfying a relation rho/sigma_r^3 propto r^-alpha, which holds for simulated dark-matter haloes over their whole resolved radial range. Considering first the case of velocity isotropy, we find that this problem has only one solution with realistic density profile, which occurs only for a critical value of alpha_crit = 35/18 ~= 1.94, which is consistent with the empirical value of 1.9+/-0.05. We extend our analysis in two ways: first we introduce a parameter epsilon to allow for a more general relation rho/\\sigma_r^epsilon propto r^-alpha; second we consider velocity anisotropy. If we assume beta(r) := 1- sigma_theta^2 / sigma_r^2 to be linearly related to the logarithmic density slope gamma(r) := -dln(rho)/dln(r), which is in agreement with simulations, the problem remains analytically tractable and is equivalent to the simpler isotropic case: there exists only one physical solution, which occurs at a critical alpha value. Remarkably, this value of alpha and the density and velocity-dispersion profiles depend only on epsilon and the value beta_0 := beta(r=0), but not on the slope of the linear beta-gamma relation. For epsilon=3, alpha_crit = 35/18 - 2beta_0/9 and the resulting density profile is fully analytic (as are the velocity dispersion and circular speed) with an inner cusp rho propto r^{-(7+10beta_0)/9} and a very smooth transition to a steeper outer power-law asymptote. These models are in excellent agreement with the density, velocity-dispersion and anisotropy profiles of simulated dark-matter haloes over their full resolved radial range. If epsilon=3 is a universal constant, some scatter in beta_0 ~= 0 may account for some diversity in the density profiles. (ABRIDGED)

Walter Dehnen; Dean McLaughlin

2005-06-22T23:59:59.000Z

419

Dynamic Spectrum Management for Green DSL  

E-Print Network [OSTI]

identified as a significant contributor to global warming. In this paper we extend traditional DSM design be balanced carefully, as increasing one user's transmit power increases its data rate but also causes

Chiang, Mung

420

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

Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

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...

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

ADAPTIVE FULL-SPECTRUM SOLOR ENERGY SYSTEMS  

SciTech Connect (OSTI)

This RD&D project is a three year team effort to develop a hybrid solar lighting (HSL) system that transports solar light from a paraboloidal dish concentrator to a luminaire via a large core polymer fiber optic. The luminaire can be a device to distribute sunlight into a space for the production of algae or it can be a device that is a combination of solar lighting and electric lighting. A benchmark prototype system has been developed to evaluate the HSL system. Sunlight is collected using a one-meter paraboloidal concentrator dish with two-axis tracking. A secondary mirror consisting of eight planar-segmented mirrors directs the visible part of the spectrum to eight fibers (receiver) and subsequently to eight luminaires. This results in about 8,200 lumens incident at each fiber tip. Each fiber can illuminate about 16.7 m{sup 2} (180 ft{sup 2}) of office space. The IR spectrum is directed to a thermophotovoltaic (TPV) array to produce electricity. During this reporting period, the project team made advancements in the design of the second generation (Alpha) system. For the Alpha system, the eight individual 12 mm fibers have been replaced with a centralized bundle of 3 mm fibers. The TRNSYS Full-Spectrum Solar Energy System model has been updated and new components have been added. The TPV array and nonimaging device have been tested and progress has been made in the fiber transmission models. A test plan was developed for both the high-lumen tests and the study to determine the non-energy benefits of daylighting. The photobioreactor team also made major advancements in the testing of model scale and bench top lab-scale systems.

Byard D. Wood

2004-04-01T23:59:59.000Z

422

Silicon Valley Power and Oklahoma Municipal Power Authority Win...  

Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

Silicon Valley Power and Oklahoma Municipal Power Authority Win 2014 Public Power Wind Awards Silicon Valley Power and Oklahoma Municipal Power Authority Win 2014 Public Power Wind...

423

Spectrum tailoring of the neutron energy spectrum in the context of delayed neutron detection  

SciTech Connect (OSTI)

For the purpose of measuring plutonium mass in spent fuel, a delayed neutron instrument is of particular interest since, if properly designed, the delayed neutron signal from {sup 235}U is significantly stronger than the signature from {sup 239}Pu or {sup 241}Pu. A key factor in properly designing a delayed neutron instrument is to minimize the fission of {sup 238}U. This minimization is achieved by keeping the interrogating neutron spectrum below {approx} 1 MeV. In the context of spent fuel measurements it is desirable to use a 14 MeV (deuterium and tritium) neutron generator for economic reasons. Spectrum tailoring is the term used to describe the inclusion of material between the 14 MeV neutrons and the interrogated object that lower the neutron energy through nuclear reactions and moderation. This report quantifies the utility of different material combination for spectrum tailoring.

Koehler, William E [Los Alamos National Laboratory; Tobin, Steve J [Los Alamos National Laboratory; Sandoval, Nathan P [Los Alamos National Laboratory; Fensin, Mike L [Los Alamos National Laboratory

2010-01-01T23:59:59.000Z

424

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.

425

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.

426

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.

427

Dark matter axions and caustic rings  

SciTech Connect (OSTI)

This report contains discussions on the following topics: the strong CP problem; dark matter axions; the cavity detector of galactic halo axions; and caustic rings in the density distribution of cold dark matter halos.

Sikivie, P.

1997-11-01T23:59:59.000Z

428

Statistical mechanics of hot dense matter  

SciTech Connect (OSTI)

Research on properties of hot dense matter produced with high intensity laser radiation is described in a brief informal review.

More, R.

1986-10-01T23:59:59.000Z

429

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

430

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

431

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

432

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

433

Initial exploration of 21-cm cosmology with imaging and power spectra from the Murchison Widefield Array  

E-Print Network [OSTI]

The Murchison Widefield Array (MWA) is a new low-frequency radio array under construction in Western Australia with a primary goal of measuring the power spectrum of the 21-cm signal from neutral hydrogen during the Epoch ...

Williams, Christopher Leigh

2012-01-01T23:59:59.000Z

434

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

SciTech Connect (OSTI)

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

435

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

436

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

437

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

438

Wind Power  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear SecurityTensile Strain Switched FerromagnetismWaste and MaterialsWenjun DengWISPWind Industry Soars to New1Wind Power

439

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

440

in2p3-00181168,version2-22Jan2008 BCS-BEC crossover of neutron pairs in symmetric and asymmetric nuclear matter  

E-Print Network [OSTI]

nuclear matter J. Margueron,1, 2 H. Sagawa,2 and K. Hagino3 1 Institut de Physique Nucl´eaire, Universit that the medium polarization effects cannot be cast into the density power law function usually introduced-BEC crossover of neutrons pairs in symmetric and asymmetric nuclear matter is studied by using these contact

Boyer, Edmond

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

FUTURE POWER GRID INITIATIVE Future Power Grid  

E-Print Network [OSTI]

FUTURE POWER GRID INITIATIVE Future Power Grid Control Paradigm OBJECTIVE This project integration & exploit the potential of distributed smart grid assets » Significantly reduce the risk of advanced mathematical models, next- generation simulation and analytics capabilities for the power grid

442

On Math, Matter and Mind  

E-Print Network [OSTI]

We discuss the nature of reality in the ontological context of Penrose's math-matter-mind triangle. The triangle suggests the circularity of the widespread view that math arises from the mind, the mind arises out of matter, and that matter can be explained in terms of math. Non-physicists should be wary of any claim that modern physics leads us to any particular resolution of this circularity, since even the sample of three theoretical physicists writing this paper hold three divergent views. Some physicists believe that current physics has already found the basic framework for a complete description of reality, and only has to fill in the details. Others suspect that no single framework, from physics or other sources, will ever capture reality. Yet others guess that reality might be approached arbitrarily closely by some form of future physics, but probably based on completely different frameworks. We will designate these three approaches as the fundamentalist, secular and mystic views of the world, as seen by practicing physicists. We present and contrast each of these views, which arguably form broad categories capturing most if not all interpretations of physics. We argue that this diversity in the physics community is more useful than an ontological monoculture, since it motivates physicists to tackle unsolved problems with a wide variety of approaches.

Piet Hut; Mark Alford; Max Tegmark

2006-01-15T23:59:59.000Z

443

Conformal Inflation Coupled to Matter  

E-Print Network [OSTI]

We formulate new conformal models of inflation and dark energy which generalise the Higgs-Dilaton scenario. We embed these models in unimodular gravity whose effect is to break scale invariance in the late time Universe. In the early Universe, inflation occurs close to a maximum of both the scalar potential and the scalar coupling to the Ricci scalar in the Jordan frame. At late times, the dilaton, which decouples from the dynamics during inflation, receives a potential term from unimodular gravity and leads to the acceleration of the Universe. We address two central issues in this scenario. First we show that the Damour-Polyalov mechanism, when non-relativistic matter is present prior to the start of inflation, sets the initial conditions for inflation at the maximum of the scalar potential. We then show that conformal invariance implies that matter particles are not coupled to the dilaton in the late Universe at the classical level. When fermions acquire masses at low energy, scale invariance is broken and quantum corrections induce a coupling between the dilaton and matter which is still small enough to evade the gravitational constraints in the solar system.

P. Brax; A. C. Davis

2014-01-28T23:59:59.000Z

444

Effects of Advanced Combustion Technologies on Particulate Matter...  

Broader source: Energy.gov (indexed) [DOE]

Effects of Advanced Combustion Technologies on Particulate Matter Emissions Characteristics Effects of Advanced Combustion Technologies on Particulate Matter Emissions...

445

Strange Quark Matter and Compact Stars  

E-Print Network [OSTI]

Astrophysicists distinguish between three different types of compact stars. These are white dwarfs, neutron stars, and black holes. The former contain matter in one of the densest forms found in the Universe which, together with the unprecedented progress in observational astronomy, make such stars superb astrophysical laboratories for a broad range of most striking physical phenomena. These range from nuclear processes on the stellar surface to processes in electron degenerate matter at subnuclear densities to boson condensates and the existence of new states of baryonic matter--like color superconducting quark matter--at supernuclear densities. More than that, according to the strange matter hypothesis strange quark matter could be more stable than nuclear matter, in which case neutron stars should be largely composed of pure quark matter possibly enveloped in thin nuclear crusts. Another remarkable implication of the hypothesis is the possible existence of a new class of white dwarfs. This article aims at giving an overview of all these striking physical possibilities, with an emphasis on the astrophysical phenomenology of strange quark matter. Possible observational signatures associated with the theoretically proposed states of matter inside compact stars are discussed as well. They will provide most valuable information about the phase diagram of superdense nuclear matter at high baryon number density but low temperature, which is not accessible to relativistic heavy ion collision experiments.

Fridolin Weber

2004-09-27T23:59:59.000Z

446

Section on prospects for dark matter detection of the white paper on the status and future of ground-based TeV gamma-ray astronomy.  

SciTech Connect (OSTI)

This is a report on the findings of the dark matter science working group for the white paper on the status and future of TeV gamma-ray astronomy. The white paper was commissioned by the American Physical Society, and the full white paper can be found on astro-ph (arXiv:0810.0444). This detailed section discusses the prospects for dark matter detection with future gamma-ray experiments, and the complementarity of gamma-ray measurements with other indirect, direct or accelerator-based searches. We conclude that any comprehensive search for dark matter should include gamma-ray observations, both to identify the dark matter particle (through the characteristics of the gamma-ray spectrum) and to measure the distribution of dark matter in galactic halos.

Byrum, K.; Horan, D.; Tait, T.; Wanger, R.; Zaharijas, G.; Buckley , J.; Baltz, E. A.; Bertone, G.; Dingus, B.; Fegan, S.; Ferrer, F.; Gondolo, P.; Hall, J.; Hooper, D.; Horan, D.; Koushiappas, S.; Krawczynksi, H.; LeBohec, S.; Pohl, M.; Profumo, S.; Silk , J; Vassilev, V.; Wood , M.; Wakely, S.; High Energy Physics; FNAL; Univ. of St. Louis; Stanford Univ.; Insti. d' Astrophysique; LANL; Univ. of California; Washington Univ.; Univ. of Utah; Brown Univ.; Oxford Univ.; Iowa State Univ.; Univ. of Chicago

2009-05-13T23:59:59.000Z

447

Southwestern Power Administration  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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...

448

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

449

Solar powered desalination system  

E-Print Network [OSTI]

2008, uses concentrated solar power to split water. Figurethe main reason the potential for solar power is boundless.a clean energy source, solar power is inexhaustible, fairly

Mateo, Tiffany Alisa

2011-01-01T23:59:59.000Z

450

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

451

ON THE INJECTION SPECTRUM OF RELATIVISTIC ELECTRONS IN HIGH-REDSHIFT RADIO GALAXIES  

SciTech Connect (OSTI)

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

452

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"

453

Dark energy and dust matter phases from an exact $f(R)$-cosmology model  

E-Print Network [OSTI]

We show that dust matter-dark energy combined phases can be achieved by the exact solution derived from a power law $f(R)$ cosmological model. This example answers the query by which a dust-dominated decelerated phase, before dark-energy accelerated phase, is needed in order to form large scale structures.

S. Capozziello; P. Martin-Moruno; C. Rubano

2008-04-28T23:59:59.000Z

454

OPTI-583: Computational Optics I: Ultrafast pulses and strong-field light-matter interactions.  

E-Print Network [OSTI]

OPTI-583: Computational Optics I: Ultrafast pulses and strong-field light-matter interactions. Time-power femtosecond pulses. Prerequisites: Knowledge of basic electromagnetic theory (e.g. Phys-241). While previous that govern the interaction of ultrashort pulses with var- ious media, and the Numerical methods track

Arizona, University of

455

DENSE MATTER IN LASER DRIVEN FUSION ! LABORATORY EXPERIMENTS R.L. Mc Crory and J. Wilson  

E-Print Network [OSTI]

irradiation to heat and compress a target containing thermonuclear fuel to fusion conditions. This is stillDENSE MATTER IN LASER DRIVEN FUSION ! LABORATORY EXPERIMENTS R.L. Mc Crory and J. Wilson Laboratory. The high power lasers in quaestion were constructed with laser fusion studies as the goal, i

Boyer, Edmond

456

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

457

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

458

Expanding the solar spectrum used by photosynthesis  

SciTech Connect (OSTI)

A limiting factor for photosynthetic organisms is their light-harvesting efficiency, that is the efficiency of their conversion of light energy to chemical energy. Small modifications or variations of chlorophylls allow photosynthetic organisms to harvest sunlight at different wavelengths. Oxygenic photosynthetic organisms usually utilize only the visible portion of the solar spectrum. The cyanobacterium Acaryochloris marina carries out oxygenic photosynthesis but contains mostly chlorophyll d and only traces of chlorophyll a. Chlorophyll d provides a potential selective advantage because it enables Acaryochloris to use infrared light (700–750 nm) that is not absorbed by chlorophyll a. Recently, an even more red-shifted chlorophyll termed chlorophyll f has been reported. Here, we discuss using modified chlorophylls to extend the spectral region of light that drives photosynthetic organisms.

Chen, Min; Blankenship, R. E.

2011-01-01T23:59:59.000Z

459

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

460

Power oscillator  

DOE Patents [OSTI]

An oscillator includes an amplifier having an input and an output, and an impedance transformation network connected between the input of the amplifier and the output of the amplifier, wherein the impedance transformation network is configured to provide suitable positive feedback from the output of the amplifier to the input of the amplifier to initiate and sustain an oscillating condition, and wherein the impedance transformation network is configured to protect the input of the amplifier from a destructive feedback signal. One example of the oscillator is a single active element device capable of providing over 70 watts of power at over 70% efficiency. Various control circuits may be employed to match the driving frequency of the oscillator to a plurality of tuning states of the lamp.

Gitsevich, Aleksandr (Montgomery Village, MD)

2001-01-01T23:59:59.000Z

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.


461

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

462

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

463

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

464

The hard X-ray spectrum of Compton-thick Seyfert 2 galaxies and the synthesis of the XRB  

E-Print Network [OSTI]

A synthesis model for the cosmic X-ray Background (XRB) is presented, which includes a proper treatment of Compton scattering in the absorbing matter for type 2 AGN. Evidence for a decrease of the relative importance of type 2 AGN at high redshift is found, which may be due either to a decrease of the relative number of obscured sources, or (more plausibly) to an increase of the fraction of Compton-thick absorbed sources. The XRB spectrum, soft X-rays and hard X-rays source counts can be simultaneously fitted only if the XRB normalization as derived from BeppoSAX/MECS measurements is adopted.

Giorgio Matt; Fulvio Pompilio; Fabio La Franca

1999-12-16T23:59:59.000Z

465

The Evolution of Galaxies by the Incompatibility between Dark Matter and Baryonic Matter  

E-Print Network [OSTI]

In this paper, the evolution of galaxies is by the incompatibility between dark matter and baryonic matter. Due to the structural difference, baryonic matter and dark matter are incompatible to each other as oil droplet and water in emulsion. In the interfacial zone between dark matter and baryonic matter, this incompatibility generates the modification of Newtonian dynamics to keep dark matter and baryonic matter apart. The five periods of baryonic structure development in the order of increasing incompatibility are the free baryonic matter, the baryonic droplet, the galaxy, the cluster, and the supercluster periods. The transition to the baryonic droplet generates density perturbation in the CMB. In the galaxy period, the first-generation galaxies include elliptical, normal spiral, barred spiral, irregular, and dwarf spheroidal galaxies. In the cluster period, the second-generation galaxies include modified giant ellipticals, cD, evolved S0, dwarf elliptical, BCD, and tidal dwarf galaxies. The whole observable expanding universe behaves as one unit of emulsion with increasing incompatibility between dark matter and baryonic matter. The properties of dark matter and baryonic matter are based on cosmology derived from the two physical structures: the space structure and the object structure. Baryonic matter can be described by the periodic table of elementary particles.

Ding-Yu Chung

2011-02-10T23:59:59.000Z

466

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

2011-01-01T23:59:59.000Z

467

Possible dark energy imprints in gravitational wave spectrum of mixed neutron-dark-energy stars  

E-Print Network [OSTI]

In the present paper we study the oscillation spectrum of neutron stars containing both ordinary matter and dark energy in different proportions. Within the model we consider, the equilibrium configurations are numerically constructed and the results show that the properties of the mixed neuron-dark-energy star can differ significantly when the amount of dark energy in the stars is varied. The oscillations of the mixed neuron-dark-energy stars are studied in the Cowling approximation. As a result we find that the frequencies of the fundamental mode and the higher overtones are strongly affected by the dark energy content. This can be used in the future to detect the presence of dark energy in the neutron stars and to constrain the dark-energy models.

Stoytcho S. Yazadjiev; Daniela D. Doneva

2011-12-19T23:59:59.000Z

468

EXTRAGALACTIC DARK MATTER AND DIRECT DETECTION EXPERIMENTS  

SciTech Connect (OSTI)

Recent astronomical data strongly suggest that a significant part of the dark matter content of the Local Group and Virgo Supercluster is not incorporated into the galaxy halos and forms diffuse components of these galaxy clusters. A portion of the particles from these components may penetrate the Milky Way and make an extragalactic contribution to the total dark matter containment of our Galaxy. We find that the particles of the diffuse component of the Local Group are apt to contribute {approx}12% to the total dark matter density near Earth. The particles of the extragalactic dark matter stand out because of their high speed ({approx}600 km s{sup -1}), i.e., they are much faster than the galactic dark matter. In addition, their speed distribution is very narrow ({approx}20 km s{sup -1}). The particles have an isotropic velocity distribution (perhaps, in contrast to the galactic dark matter). The extragalactic dark matter should provide a significant contribution to the direct detection signal. If the detector is sensitive only to the fast particles (v > 450 km s{sup -1}), then the signal may even dominate. The density of other possible types of the extragalactic dark matter (for instance, of the diffuse component of the Virgo Supercluster) should be relatively small and comparable with the average dark matter density of the universe. However, these particles can generate anomaly high-energy collisions in direct dark matter detectors.

Baushev, A. N., E-mail: baushev@gmail.com [DESY, D-15738 Zeuthen (Germany); Institut fuer Physik und Astronomie, Universitaet Potsdam, D-14476 Potsdam-Golm (Germany)

2013-07-10T23:59:59.000Z

469

On the essential spectrum of certain non-commutative oscillators  

SciTech Connect (OSTI)

We show here that the spectrum of the family of non-commutative harmonic oscillators Q{sub (?,?)}{sup w}(x,D) for ?,??R{sub +} in the range ?? = 1 is [0, +?) and is entirely essential spectrum. The previous existing results concern the case ?? > 1 (case in which Q{sub (?,?)}{sup w}(x,D) is globally elliptic with a discrete spectrum whose qualitative properties are being extensively studied), and ours therefore extend the picture to the range of parameters ?? ? 1.

Parmeggiani, Alberto, E-mail: alberto.parmeggiani@unibo.it; Venni, Alberto, E-mail: alberto.venni@unibo.it [Department of Mathematics, University of Bologna, Piazza di Porta S.Donato 5, 40126 Bologna (Italy)] [Department of Mathematics, University of Bologna, Piazza di Porta S.Donato 5, 40126 Bologna (Italy)

2013-12-15T23:59:59.000Z

470

Superconducting Radio Frequency Cavities as Axion Dark Matter Detectors  

E-Print Network [OSTI]

A modification of the cavity technique for axion dark matter detection is described in which the cavity is driven with input power instead of being permeated by a static magnetic field. A small fraction of the input power is pumped by the axion field to a receiving mode of frequency $\\omega_1$ when the resonance condition $\\omega_1 = \\omega_0 \\pm m_a$ is satisfied, where $\\omega_0$ is the frequency of the input mode and $m_a$ the axion mass. The relevant form factor is calculated for any pair of input and output modes in a cylindrical cavity. The overall search strategy is discussed and the technical challenges to be overcome by an actual experiment are listed.

P. Sikivie

2013-01-20T23:59:59.000Z

471

Spectrum of the volume integral operator of electromagnetic scattering  

E-Print Network [OSTI]

Spectrum of the volume integral operator of the three-dimensional electromagnetic scattering is analyzed. The operator has both continuous essential spectrum, which dominates at lower frequencies, and discrete eigenvalues, which spread out at higher ones. The explicit expression of the operator's symbol provides exact outline of the essential spectrum for any inhomogeneous anisotropic scatterer with Holder continuous constitutive parameters. Geometrical bounds on the location of discrete eigenvalues are derived for various physical scenarios. Numerical experiments demonstrate good agreement between the predicted spectrum of the operator and the eigenvalues of its discretized version.

Neil V. Budko; Alexander B. Samokhin

2005-05-04T23:59:59.000Z

472

age spectrum epidemiology: Topics by E-print Network  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

of a young supernova. We associate this break with the phenomenon of synchrotron aging of radiating electrons. From the break in the spectrum we calculate the magnetic field...

473

auditory neuropathy spectrum: Topics by E-print Network  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

of symptoms concentrate on speech and language development, especially ... Bullock, Bennett (Bennett Charles) 2010-01-01 3 Multisensory integration in autism spectrum disorders:...

474

Use Remote Sensing Data (selected visible and infrared spectrums...  

Broader source: Energy.gov (indexed) [DOE]

Use Remote Sensing Data (selected visible and infrared spectrums) to locate high temperature ground anomalies in Colorado. Confirm heat flow potential with on-site surveys to drill...

475

An hybrid Tykhonov method for neutron spectrum unfolding  

E-Print Network [OSTI]

An hybrid iterative Tykhonov regularization approach with an accelerating algorithm is considered. This method is illustrated by two neutron spectrum unfoldings measured with a Bonner Sphere system.

Olivier Besida

2005-06-30T23:59:59.000Z

476

Wideband and Narrowband Spectrum Sensing Methods Using Software Defined Radios.  

E-Print Network [OSTI]

??The ability to accurately sense the surrounding wireless spectrum, without having any prior information about the type of signals present, is an important aspect for… (more)

Stegman, Jason Karl

2014-01-01T23:59:59.000Z

477

Spectrum hole identification and exploitation in cognitive radio networks.  

E-Print Network [OSTI]

??Cognitive radio networks are envisaged as the solution for effective spectrum management for the future communications. In a cognitive radio network, the unlicensed users are… (more)

Vamsi Krishna Tumuluru.

2011-01-01T23:59:59.000Z

478

Priority Queuing Based Spectrum sensing Methodology in Cognitive Radio Network.  

E-Print Network [OSTI]

??Radio spectrum is becoming scarce resource due to increase in the usage of wireless communication devices. However studies have revealed that most of the allotted… (more)

[email protected; /* */, Sajid

2011-01-01T23:59:59.000Z

479

Statistical Issues in Astrophysical Searches for Particle Dark Matter  

E-Print Network [OSTI]

In this review statistical issues appearing in astrophysical searches for particle dark matter, i.e. indirect detection (dark matter annihilating into standard model particles) or direct detection (dark matter particles scattering in deep underground detectors) are discussed. One particular aspect of these searches is the presence of very large uncertainties in nuisance parameters (astrophysical factors) that are degenerate with parameters of interest (mass and annihilation/decay cross sections for the particles). The likelihood approach has become the most powerful tool, offering at least one well motivated method for incorporation of nuisance parameters and increasing the sensitivity of experiments by allowing a combination of targets superior to the more traditional data stacking. Other statistical challenges appearing in astrophysical searches are to large extent similar to any new physics search, for example at colliders, a prime example being the calculation of trial factors. Frequentist methods prevail for hypothesis testing and interval estimation, Bayesian methods are used for assessment of nuisance parameters and parameter estimation in complex parameter spaces. The basic statistical concepts will be exposed, illustrated with concrete examples from experimental searches and caveats will be pointed out.

Jan Conrad

2014-10-14T23:59:59.000Z

480

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

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

Dark Matter in the MSSM  

SciTech Connect (OSTI)

We have recently examined a large number of points in the parameter space of the phenomenological MSSM, the 19-dimensional parameter space of the CP-conserving MSSM with Minimal Flavor Violation. We determined whether each of these points satisfied existing experimental and theoretical constraints. This analysis provides insight into general features of the MSSM without reference to a particular SUSY breaking scenario or any other assumptions at the GUT scale. This study opens up new possibilities for SUSY phenomenology both in colliders and in astrophysical experiments. Here we shall discuss the implications of this analysis relevant to the study of dark matter.

Cotta, R.C.; Gainer, J.S.; Hewett, J.L.; Rizzo, T.G.; /SLAC

2009-04-07T23:59:59.000Z

482

Initial value constraints with tensor matter  

E-Print Network [OSTI]

In generally covariant metric gravity theories with tensor matter fields, the initial value constraint equations, unlike in general relativity, are in general not just the 0\\mu-components of the metric field equation. This happens because higher derivatives can occur in the matter stress tensor. A universal form for these constraints is derived here from a generalized Bianchi identity that includes matter fields. As an application, the constraints for Einstein-aether theory are found.

Ted Jacobson

2011-08-06T23:59:59.000Z

483

Lorentz violation and Condensed Matter Physics  

E-Print Network [OSTI]

We present heuristic arguments that hint to a possible connection of Lorentz violation with observed phenomenon in condensed matter physics. Various references from condensed matter literature are cited where operators in the Standard Model Extension (SME) appear to be enhanced. Based on this we propose that, in the non-relativistic limit, Lorentz violation in the context of the SME exhibits itself in various condensed matter systems.

Muhammad Adeel Ajaib

2014-03-29T23:59:59.000Z

484

Noble Travails: Noble Liquid Dark Matter Detectors  

E-Print Network [OSTI]

, or water, 0.1x flux per 10 cm Cosmic Ray Muons generate high energy neutrons 50 MeV - 3 GeV which are toughGaitskell Noble Travails: Noble Liquid Dark Matter Detectors Rick Gaitskell Particle Astrophysics://particleastro.brown.edu/ http://gaitskell.brown.edu v1 #12;LUX Dark Matter Collaboration 2007 v01_7mm Dark Matter Theory

Golwala, Sunil

485

Axion Dark Matter Detection using Atomic Transitions  

E-Print Network [OSTI]

Dark matter axions may cause transitions between atomic states that differ in energy by an amount equal to the axion mass. Such energy differences are conveniently tuned using the Zeeman effect. It is proposed to search for dark matter axions by cooling a kilogram-sized sample to milliKelvin temperatures and count axion induced transitions using laser techniques. This appears an appropriate approach to axion dark matter detection in the $10^{-4}$ eV mass range.

P. Sikivie

2014-09-09T23:59:59.000Z

486

Residual Energy Spectrum of Solar Wind Turbulence  

E-Print Network [OSTI]

It has long been known that the energy in velocity and magnetic field fluctuations in the solar wind is not in equipartition. In this paper, we present an analysis of 5 years of Wind data at 1 AU to investigate the reason for this. The residual energy (difference between energy in velocity and magnetic field fluctuations) was calculated using both the standard magnetohydrodynamic (MHD) normalization for the magnetic field and a kinetic version, which includes temperature anisotropies and drifts between particle species. It was found that with the kinetic normalization, the fluctuations are closer to equipartition, with a mean normalized residual energy of sigma_r = -0.19 and mean Alfven ratio of r_A = 0.71. The spectrum of residual energy, in the kinetic normalization, was found to be steeper than both the velocity and magnetic field spectra, consistent with some recent MHD turbulence predictions and numerical simulations, having a spectral index close to -1.9. The local properties of residual energy and cros...

Chen, C H K; Salem, C S; Maruca, B A

2013-01-01T23:59:59.000Z

487

THE SUBMILLIMETER POLARIZATION SPECTRUM OF M17  

SciTech Connect (OSTI)

We present 450 {mu}m polarimetric observations of the M17 molecular cloud obtained with the SHARP polarimeter at the Caltech Submillimeter Observatory. Across the observed region, the magnetic field orientation is consistent with previous submillimeter and far-infrared polarization measurements. Our observations are centered on a region of the molecular cloud that has been compressed by stellar winds from a cluster of OB stars. We have compared these new data with previous 350 {mu}m polarimetry and find an anti-correlation between the 450 and 350 {mu}m polarization magnitude ratio and the ratio of 21 cm to 450 {mu}m intensity. The polarization ratio is lower near the east end of the studied region where the cloud is exposed to stellar winds and radiation. At the west end of the region, the polarization ratio is higher. We interpret the varying polarization spectrum as evidence supporting the radiative alignment torque model for grain alignment, implying higher alignment efficiency in the region that is exposed to a higher anisotropic radiation field.

Zeng Lingzhen; Jimenez-Serra, Izaskun [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Bennett, Charles L. [Department of Physics and Astronomy, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218 (United States); Chapman, Nicholas L.; Novak, Giles [Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA) and Department of Physics and Astronomy, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208 (United States); Chuss, David T. [Observational Cosmology Laboratory, NASA Goddard Space Flight Center, Code 665, Greenbelt, MD 20771 (United States); Vaillancourt, John E., E-mail: lingzhen@cfa.harvard.edu [SOFIA Science Center, Universities Space Research Association, NASA Ames Research Center, MS 232-11, Moffett Field, CA 94035 (United States)

2013-08-10T23:59:59.000Z

488

Apparatus for synthesis of a solar spectrum  

DOE Patents [OSTI]

A xenon arc lamp and a tungsten filament lamp provide light beams that together contain all the wavelengths required to accurately simulate a solar spectrum. Suitable filter apparatus selectively direct visible and ultraviolet light from the xenon arc lamp into two legs of a trifurcated randomized fiber optic cable. Infrared light selectively filtered from the tungsten filament lamp is directed into the third leg of the fiber optic cable. The individual optic fibers from the three legs are brought together in a random fashion into a single output leg. The output beam emanating from the output leg of the trifurcated randomized fiber optic cable is extremely uniform and contains wavelengths from each of the individual filtered light beams. This uniform output beam passes through suitable collimation apparatus before striking the surface of the solar cell being tested. Adjustable aperture apparatus located between the lamps and the input legs of the trifurcated fiber optic cable can be selectively adjusted to limit the amount of light entering each leg, thereby providing a means of "fine tuning" or precisely adjusting the spectral content of the output beam. Finally, an adjustable aperture apparatus may also be placed in the output beam to adjust the intensity of the output beam without changing the spectral content and distribution of the output beam.

Sopori, Bhushan L. (Denver, CO)

1993-01-01T23:59:59.000Z

489

Mass spectrum of primordial black holes from inflationary perturbation in the Randall-Sundrum braneworld: a limit on blue spectra  

E-Print Network [OSTI]

The mass spectrum of the primordial black holes formed by density perturbation in the radiation-dominated era of the Randall-Sundrum type-2 cosmology is given. The spectrum coincides with standard four-dimensional one on large scales but the deviation is apparent on smaller scales. The mass spectrum is initially softer than standard four-dimensional one, while after accretion during the earliest era it becomes harder than that. We also show expected extragalactic diffuse photon background spectra varying the initial perturbation power-law power spectrum and give constraints on the blue spectra and/or the reheating temperature. The most recent observations on the small scale density perturbation from WMAP, SDSS and Lyman-\\alpha Forest are used. What we get are interpreted as constraints on the smaller scale inflation on the brane connected to the larger one at the scale of Lyman-\\alpha Forest. If we set the bulk curvature radius to be 0.1 mm and assume the reheating temperature is higher than 10^6 GeV, the scalar spectral index from the smaller scale inflation is constrained to be n \\lesssim 1.3. Typically, the constraints are tighter than standard four-dimensional one, which is also revised by us using the most recent observations.

Yuuiti Sendouda; Shigehiro Nagataki; Katsuhiko Sato

2006-06-07T23:59:59.000Z

490

Energy Harvesting for Self-Powered Wireless Sensors  

E-Print Network [OSTI]

transmitter is designed to transfer large amounts of information with little concern for power consumption. This second method of data transmission divides the 3-10GHz spectrum into 528MHz sub-bands and "hops" between these sub-bands during data transmission...

Wardlaw, Jason

2012-02-14T23:59:59.000Z

491

HIGH AVERAGE POWER UV FREE ELECTRON LASER EXPERIMENTS AT JLAB  

SciTech Connect (OSTI)

Having produced 14 kW of average power at {approx}2 microns, JLAB has shifted its focus to the ultraviolet portion of the spectrum. This presentation will describe the JLab UV Demo FEL, present specifics of its driver ERL, and discuss the latest experimental results from FEL experiments and machine operations.

Douglas, David; Evtushenko, Pavel; Gubeli, Joseph; Hernandez-Garcia, Carlos; Legg, Robert; Neil, George; Powers, Thomas; Shinn, Michelle D; Tennant, Christopher

2012-07-01T23:59:59.000Z

492

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

SciTech Connect (OSTI)

We compare results of four public supersymmetric spectrum codes, ISAJET 7.71, SOFTSUSY 1.9, SPHENO 2.2.2 and SUSPECT 2.3 to estimate the present-day uncertainty in the calculation of the relic density of dark matter in minimal supergravity 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{sub 0}, discrepancies in the relic density are much larger. We also find important differences in the stau coannihilation region. We show the impact of these uncertainties on the bounds from Wilkinson Microwave Anisotropy Probe for several scenarios, concentrating on the regions of parameter space most relevant for collider phenomenology. We also discuss the case of A{sub 0}{ne}0 and the stop coannihilation region. Moreover, we present a World Wide Web application for the online comparison of the spectrum codes.

Belanger, G. [Laboratoire de Physique Theorique LAPTH, F-74941 Annecy-le-Vieux (France); Kraml, S. [CERN, Department of Physics, Theory Division, CH-1211 Geneva 23 (Switzerland); Pukhov, A. [Skobeltsyn Institute of Nuclear Physics, Moscow State University, Moscow 119992 (Russian Federation)

2005-07-01T23:59:59.000Z

493

ALS Reveals New State of Matter  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

papers and extensive news coverage of their work on a new state of matter embodied by "topological insulators," materials that conduct electricity only on their surfaces. First...

494

Condensed Matter Theory Center Fall 2009 Symposium  

E-Print Network [OSTI]

Condensed Matter Theory Center Fall 2009 Symposium September 28 - October 2, 2009 2202 Physics Barnett, "Vortex lattice locking in rotating BECs and spinor condensates" Maxim Dzero, "Cooper pair

Lathrop, Daniel P.

495

Quantum Condensates in Nuclear Matter: Problems  

E-Print Network [OSTI]

In connection with the contribution "Quantum Condensates in Nuclear Matter" some problems are given to become more familiar with the techniques of many-particle physics.

G. Ropke; D. Zablocki

2010-01-11T23:59:59.000Z

496

Dark Energy and Dark Matter Models  

E-Print Network [OSTI]

We revisit the problems of dark energy and dark matter and several models designed to explain them, in the light of some latest findings.

Burra G. Sidharth

2015-01-07T23:59:59.000Z

497

PROBING DENSE NUCLEAR MATTER VIA NUCLEAR COLLISIONS  

E-Print Network [OSTI]

University of California. LBL-12095 Probing Dense NuclearMatter Nuclear Collisions* v~a H. Stocker, M.Gyulassy and J. Boguta Nuclear Science Division Lawrence

Stocker, H.

2012-01-01T23:59:59.000Z

498

Dissipative dark matter explains rotation curves  

E-Print Network [OSTI]

Dissipative dark matter, where dark matter particles interact with a massless (or very light) boson, is studied. Such dark matter can arise in simple hidden sector gauge models, including those featuring an unbroken $U(1)'$ gauge symmetry, leading to a dark photon. Previous work has shown that such models can not only explain the LSS and CMB, but potentially also dark matter phenomena on small scales, such as the inferred cored structure of dark matter halos. In this picture, dark matter halos of disk galaxies not only cool via dissipative interactions but are also heated via ordinary supernovae (facilitated by an assumed photon - dark photon kinetic mixing interaction). This interaction between the dark matter halo and ordinary baryons, a very special feature of these types of models, plays a critical role in governing the physical properties of the dark matter halo. Here, we further study the implications of this type of dissipative dark matter for disk galaxies. Building on earlier work, we develop a s