Sample records for cold clumpy absorbers

  1. Clumpy cold dark matter

    NASA Technical Reports Server (NTRS)

    Silk, Joseph; Stebbins, Albert

    1993-01-01

    A study is conducted of cold dark matter (CDM) models in which clumpiness will inhere, using cosmic strings and textures suited to galaxy formation. CDM clumps of 10 million solar mass/cu pc density are generated at about z(eq) redshift, with a sizable fraction surviving. Observable implications encompass dark matter cores in globular clusters and in galactic nuclei. Results from terrestrial dark matter detection experiments may be affected by clumpiness in the Galactic halo.

  2. Clumpy Cold Dark Matter and Biological Extinctions

    E-print Network

    J. I. Collar

    1995-12-10

    Cosmological models with cosmic string and texture seeded universes predict a present abundance of very dense clumps of Cold Dark Matter particles. Their crossing through the solar system would induce a non-negligible amount of radiation damage to all living tissue; the severity of such an episode is assessed. The estimated frequency of these crossings agrees with the apparent periodicity of the paleontological record of biological extinctions. (Phys. Lett. B, in press)

  3. A Submillimeter Galaxy Illuminating its Circumgalactic Medium: Ly? Scattering in a Cold, Clumpy Outflow

    NASA Astrophysics Data System (ADS)

    Geach, J. E.; Bower, R. G.; Alexander, D. M.; Blain, A. W.; Bremer, M. N.; Chapin, E. L.; Chapman, S. C.; Clements, D. L.; Coppin, K. E. K.; Dunlop, J. S.; Farrah, D.; Jenness, T.; Koprowski, M. P.; Micha?owski, M. J.; Robson, E. I.; Scott, D.; Smith, D. J. B.; Spaans, M.; Swinbank, A. M.; van der Werf, P.

    2014-09-01

    We report the detection at 850 ?m of the central source in SSA22-LAB1, the archetypal "Lyman-? Blob" (LAB), a 100 kpc scale radio-quiet emission-line nebula at z = 3.1. The flux density of the source, S 850 = 4.6 ± 1.1 mJy, implies the presence of a galaxy or group of galaxies with a total luminosity of L IR ? 1012 L ?. The position of an active source at the center of a ~50 kpc radius ring of linearly polarized Ly? emission detected by Hayes et al. suggests that the central source is leaking Ly? photons preferentially in the plane of the sky, which undergo scattering in H I clouds at a large galactocentric radius. The Ly? morphology around the submillimeter detection is reminiscent of a biconical outflow, and the average Ly? line profiles of the two "lobes" are dominated by a red peak, which is expected for a resonant line emerging from a medium with a bulk velocity gradient that is outflowing relative to the line center. Taken together, these observations provide compelling evidence that the central active galaxy (or galaxies) is responsible for a large fraction of the extended Ly? emission and morphology. Less clear is the history of the cold gas in the circumgalactic medium being traced by Ly?: is it mainly pristine material accreting into the halo that has not yet been processed through an interstellar medium (ISM), now being blown back as it encounters an outflow, or does it mainly comprise gas that has been swept-up within the ISM and expelled from the galaxy?

  4. Nearby Clumpy, Gas Rich, Star-forming Galaxies: Local Analogs of High-redshift Clumpy Galaxies

    NASA Astrophysics Data System (ADS)

    Garland, C. A.; Pisano, D. J.; Mac Low, M.-M.; Kreckel, K.; Rabidoux, K.; Guzmán, R.

    2015-07-01

    Luminous compact blue galaxies (LCBGs) have enhanced star formation rates (SFRs) and compact morphologies. We combine Sloan Digital Sky Survey data with H i data of 29 LCBGs at redshift z ? 0 to understand their nature. We find that local LCBGs have high atomic gas fractions (?50%) and SFRs per stellar mass consistent with some high-redshift star-forming galaxies (SFGs). Many local LCBGs also have clumpy morphologies, with clumps distributed across their disks. Although rare, these galaxies appear to be similar to the clumpy SFGs commonly observed at z ? 1–3. Local LCBGs separate into three groups: (1) interacting galaxies (?20%) (2) clumpy spirals (?40%) and (3) non-clumpy, non-spirals with regular shapes and smaller effective radii and stellar masses (?40%). It seems that the method of building up a high gas fraction, which then triggers star formation, is not the same for all local LCBGs. This may lead to a dichotomy in galaxy characteristics. We consider possible gas delivery scenarios and suggest that clumpy spirals, preferentially located in clusters and with companions, are smoothly accreting gas from tidally disrupted companions and/or intracluster gas enriched by stripped satellites. Conversely, as non-clumpy galaxies are preferentially located in the field and tend to be isolated, we suggest clumpy, cold streams, which destroy galaxy disks and prevent clump formation, as a likely gas delivery mechanism for these systems. Other possibilities include smooth cold streams, a series of minor mergers, or major interactions.

  5. The discovery of large amounts of cold, X-ray absorbing matter in cooling flows

    NASA Technical Reports Server (NTRS)

    White, D. A.; Fabian, A. C.; Johnstone, R. M.; Mushotzky, R. F.; Arnaud, K. A.

    1991-01-01

    The discovery of significant excess absorption in the X-ray spectra of 12 clusters of galaxies is reported. The spectra also require a cooling-flow component, which confirms the results of imaging studies of the clusters showing the strongly peaked emission characteristic of cooling flows. The total mass of absorbing gas is determined on the assumption that it is distributed through the cooling flow region and has cosmic abundance. It is shown that the gas is most likely in the form of small cold clouds. The excess absorption is interpreted as being due to photoelectric absorption in cold gas clouds distributed through the cooling flows.

  6. High-z QSO Absorption Systems: Metal-Poor Cold Flows and Mg II Absorber Host Galaxies

    NASA Astrophysics Data System (ADS)

    Cooper, Thomas; Simcoe, R. A.; Cooksey, K.; O'Meara, J.

    2014-01-01

    Cosmological simulations have suggested a new model for gas accretion in young galaxies, in which baryons flow into the star-forming disk along filamentary streams without shock heating at the dark matter halo virial radius. Observationally, these cold flows manifest as Lyman Limit Systems with low heavy element abundances. To search for cold flows in the early Universe, we have obtained echellette-resolution spectra of an HI-selected sample of LLS at z>3.5 from the Sloan Digital Sky Survey. The sightlines were selected to exhibit no heavy element absorption at the resolution afforded by SDSS, and the higher resolution data provides metallicity measurements precise enough to determine if they exhibit cold flow accretion characteristics. In a parallel program, we use the Magellan Telescopes and HST/WFC-3 to investigate the connection between Mg II absorbers and proximate galaxies at 3, extending fruitful studies of the circumgalactic medium to larger redshift.

  7. A Deep Search for Faint Galaxies Associated with Very Low-redshift C IV Absorbers: A Case with Cold-accretion Characteristics

    NASA Astrophysics Data System (ADS)

    Burchett, Joseph N.; Tripp, Todd M.; Werk, Jessica K.; Howk, J. Christopher; Prochaska, J. Xavier; Ford, Amanda Brady; Davé, Romeel

    2013-12-01

    Studies of QSO absorber-galaxy connections are often hindered by inadequate information on whether faint/dwarf galaxies are located near the QSO sight lines. To investigate the contribution of faint galaxies to QSO absorber populations, we are conducting a deep galaxy redshift survey near low-z C IV absorbers. Here we report a blindly detected C IV absorption system (z abs = 0.00348) in the spectrum of PG1148+549 that appears to be associated either with an edge-on dwarf galaxy with an obvious disk (UGC 6894, z gal = 0.00283) at an impact parameter of ? = 190 kpc or with a very faint dwarf irregular galaxy at ? = 23 kpc, which is closer to the sightline but has a larger redshift difference (z gal = 0.00107, i.e., ?v = 724 km s-1). We consider various gas/galaxy associations, including infall and outflows. Based on current theoretical models, we conclude that the absorber is most likely tracing (1) the remnants of an outflow from a previous epoch, a so-called "ancient outflow", or (2) intergalactic gas accreting onto UGC 6894, "cold mode" accretion. The latter scenario is supported by H I synthesis imaging data that shows the rotation curve of the disk being codirectional with the velocity offset between UGC 6894 and the absorber, which is located almost directly along the major axis of the edge-on disk. Based on observations obtained with the NASA/ESA Hubble Space Telescope operated at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555. Also, based on data acquired using the Large Binocular Telescope (LBT). The LBT is an international collaboration among institutions in the US, Italy, and Germany. LBT Corporation partners are the University of Arizona, on behalf of the Arizona University System; Instituto Nazionale do Astrofisica, Italy; LBT Beteiligungsgesellschaft, Germany, representing the Max Planck Society, the Astrophysical Institute of Potsdam, and Heidelberg University; Ohio State University, and the Research Corporation, on behalf of the University of Notre Dame, the University of Minnesota, and the University of Virginia. Observations reported here were obtained at the MMT Observatory, a joint facility of the University of Arizona and the Smithsonian Institution.

  8. The Search for Diversities in Clumpy Galaxies

    NASA Astrophysics Data System (ADS)

    Soto, Emmaris; De Mello, D. F.; Bond, N. A.; Rafelski, M.; Gardner, J. P.; Teplitz, H. I.; UV UDF Team

    2014-01-01

    We present an investigation utilizing the deepest ultraviolet data in the Hubble Ultra Deep Field (HUDF) taken with Wide Field Camera 3 UVIS detector (90 orbits taken with F225W, F275W and F336W filters) during 3 epochs. Preliminary studies using selected galaxies in epochs 1 + 2 (F275W) show disks with clumps indicative of star forming regions. Here we present the analysis of the new epoch 3 data with the F275W band comprised of about 230 galaxies, many of which have a variety of clumps - from single clumps to galaxies littered with clumps. We perform a morphological study of ultraviolet-detected sources at redshifts 0.5 < z < 1.5 in the optical rest-frame. We used a morphological classification scheme similar to that employed by the Hubble CANDELS survey team and find that most of the clumpy objects are disks, followed by irregulars. We calculated both clump sizes and luminosities in the rest-frame UV. We find that the majority of these UV bright clumpy galaxies are classified as Scd and starburst spectral types and have clump sizes between 0.7 to 1.9 kpc.

  9. Parameters of type IIP SN 2012A and clumpiness effects

    NASA Astrophysics Data System (ADS)

    Utrobin, V. P.; Chugai, N. N.

    2015-03-01

    Context. The explosion energy and the ejecta mass of a type IIP supernova (SN IIP) derived from hydrodynamic simulations are principal parameters of the explosion theory. Few SNe IIP have been studied by hydrodynamic modeling so far, however. Some doubts exist about the reliability of the derived SN IIP parameters. Aims: We studied the well-observed type IIP SN 2012A with hydrodynamic modeling. We examined its early spectra for ejecta clumpiness. We also explored other observational effects of clumpiness. Methods: We determined the supernova parameters by means of standard hydrodynamic modeling. We used the early hydrogen H? and H? lines as clumpiness diagnostics. We used a modified hydrodynamic code to study the clumpiness effect in the light curve and expansion kinematics. Results: We found that SN 20012A is the result of the explosion of a red supergiant with a radius of 715 ± 100 R?. The explosion energy is (5.25 ± 0.6) × 1050 erg, the ejecta mass is 13.1 ± 0.7 M?, and the total 56Ni mass is 0.012 ± 0.002 M?. The estimated mass of a progenitor, a main-sequence star, is 15 ± 1 M?. The H? and H? lines in early spectra indicate that outer ejecta are clumpy. Hydrodynamic simulations show that the clumpiness modifies the early light curve and increases the maximum velocity of the outer layers. Conclusions: The pre-SN 2012A was a normal red supergiant with the progenitor mass of ? 15 M?. The outer layers of ejecta indicate the clumpy structure. The clumpiness of the external layers can increase the maximum expansion velocity.

  10. Cassiopeia A and its Clumpy Presupernova Wind

    E-print Network

    Roger A. Chevalier; Jeffrey Oishi

    2003-06-18

    The observed shock wave positions and expansion in Cas A can be interpreted in a model of supernova interaction with a freely expanding stellar wind with a mass loss rate of ~3e-5 Msun/yr for a wind velocity of 10 km/s. The wind was probably still being lost at the time of the supernova, which may have been of Type IIn or IIb. The wind may play a role in the formation of very fast knots observed in Cas A. In this model, the quasi-stationary flocculi (QSFs) represent clumps in the wind, with a density contrast of several 1000 compared to the smooth wind. The outer, unshocked clumpy wind is photoionized by radiation from the supernova, and is observed as a patchy HII region around Cas A. This gas has a lower density than the QSFs and is heated by nonradiative shocks driven by the blast wave. Denser clumps have recombined and are observed as HI compact absorption features towards Cas A.

  11. MASSIVE BLACK HOLE PAIRS IN CLUMPY, SELF-GRAVITATING CIRCUMNUCLEAR DISKS: STOCHASTIC ORBITAL DECAY

    SciTech Connect

    Fiacconi, Davide; Mayer, Lucio; Roškar, Rok [Institute for Theoretical Physics, University of Zurich, Winterthurerstrasse 190, CH-8057 Zürich (Switzerland)] [Institute for Theoretical Physics, University of Zurich, Winterthurerstrasse 190, CH-8057 Zürich (Switzerland); Colpi, Monica, E-mail: fiacconi@physik.uzh.ch [Dipartimento di Fisica 'G. Occhialini', Università di Milano-Bicocca, Piazza della Scienza 3, I-20126 Milano (Italy)] [Dipartimento di Fisica 'G. Occhialini', Università di Milano-Bicocca, Piazza della Scienza 3, I-20126 Milano (Italy)

    2013-11-01

    We study the dynamics of massive black hole pairs in clumpy gaseous circumnuclear disks. We track the orbital decay of the light, secondary black hole M {sub .2} orbiting around the more massive primary at the center of the disk, using N-body/smoothed particle hydrodynamic simulations. We find that the gravitational interaction of M {sub .2} with massive clumps M {sub cl} erratically perturbs the otherwise smooth orbital decay. In close encounters with massive clumps, gravitational slingshots can kick the secondary black hole out of the disk plane. The black hole moving on an inclined orbit then experiences the weaker dynamical friction of the stellar background, resulting in a longer orbital decay timescale. Interactions between clumps can also favor orbital decay when the black hole is captured by a massive clump that is segregating toward the center of the disk. The stochastic behavior of the black hole orbit emerges mainly when the ratio M {sub .2}/M {sub cl} falls below unity, with decay timescales ranging from ?1 to ?50 Myr. This suggests that describing the cold clumpy phase of the interstellar medium in self-consistent simulations of galaxy mergers, albeit so far neglected, is important to predict the black hole dynamics in galaxy merger remnants.

  12. CLUMPY GALAXIES IN GOODS AND GEMS: MASSIVE ANALOGS OF LOCAL DWARF IRREGULARS

    SciTech Connect

    Elmegreen, Debra Meloy; Marcus, Max T.; Yau, Andrew [Vassar College, Department of Physics and Astronomy, Box 745, Poughkeepsie, NY 12604 (United States); Elmegreen, Bruce G. [IBM Research Division, T.J. Watson Research Center, P.O. Box 218, Yorktown Heights, NY 10598 (United States); Shahinyan, Karlen [Wesleyan University, Department of Astronomy, Middletown, CT 06459 (United States); Petersen, Michael [Colgate University, Department of Physics and Astronomy, Hamilton, NY 13346 (United States)], E-mail: elmegreen@vassar.edu, E-mail: mamarcus@vassar.edu, E-mail: anyau@vassar.edu, E-mail: bge@watson.ibm.com, E-mail: kshahinyan@wesleyan.edu, E-mail: mpetersen@students.colgate.edu

    2009-08-10

    Clumpy galaxies in the Galaxy Evolution from Morphology and SEDs and Great Observatories Origins Deep Survey fields are examined for clues to their evolution into modern spirals. The magnitudes of the clumps and the surface brightnesses of the interclump regions are measured and fitted to models of stellar age and mass. There is an evolutionary trend from clump clusters with no evident interclump emission to clump clusters with faint red disks, to spiral galaxies of the flocculent or grand design types. Along this sequence, the interclump surface density increases and the mass surface density contrast between the clumps and the interclump regions decreases, suggesting a gradual dispersal of clumps to form disks. Also along this sequence, the bulge-to-clump mass ratios and age ratios increase, suggesting a gradual formation of bulges. All of these morphological types occur in the same redshift range, indicating that the clump cluster morphology is not the result of bandshifting. This redshift range also includes clear examples of interacting galaxies with tidal tails and other characteristic features, indicating that clump clusters, which do not have these features, are not generally interacting. Comparisons to local galaxies with the same rest wavelength and spatial resolution show that clump clusters are unlike local flocculent and spiral galaxies primarily because of the high clump/interclump contrasts in the clump clusters. They bear a striking resemblance to local dwarf irregulars, however. This resemblance is consistent with a model in which the clumpy morphology comes from gravitational instabilities in gas with a high turbulent speed compared to the rotation speed and a high mass fraction compared to the stars. The morphology does not depend on galaxy mass as much as it depends on evolutionary stage: clump clusters are 100 times more massive than local dwarfs. The apparent lack of star formation in damped Lyman alpha absorbers may result from fast turbulence.

  13. The dynamical and radiative evolution of clumpy supernova ejecta

    NASA Technical Reports Server (NTRS)

    Anderson, M. C.; Jones, T. W.; Rudnick, L.; Tregillis, I. L.; Kang, Hyesung

    1994-01-01

    Numerical simulations describing the dynamical and radiative evolution of clumpy supernova ejecta are compared with observations of optical and radio emission knots in supernova remnant (SNR) Cassiopeia A. Three major phases are identified in the evolution of clumpy ejecta: a bow-shock phase, an instability phase, and a dispersal phase. The phenomenological and radiative signatures of each phase are discussed and compared with multi-epoch measurements of small-scale features in Cas A. Good correspondence is found between theory and observations. Both support the premise that compact radio emission features are controlled more by magnetic field amplification triggered in the instability phase than by in situ acceleration of new relativistic particles.

  14. Multiple Scattering in Clumpy Media. II. Galactic Environments

    E-print Network

    Adolf N. Witt; Karl D. Gordon

    1999-07-25

    We present and discuss the results of new multiple-scattering radiative transfer calculations for three representative types of galactic environments, filled with either homogeneous or two-phase clumpy dust distributions. Extinction and scattering properties for two types of interstellar dust, similar to those found in the average diffuse medium of the Milky Way Galaxy (MW) and the Bar of the Small Magellanic Cloud (SMC), are considered. The wavelength coverage extends from 1000 A to 30,000 A, with particular emphasis on the rest-frame UV. This makes these models especially applicable to starburst galaxies and Lyman-break galaxy samples. The examination of the models concentrates on the study of UV/visual/near-IR reddening effects, the wavelength dependence of attenuation, and on the changes that arise from the transition from homogeneous to clumpy dust distributions in different star/dust geometries. Embedded dust, especially when clumpy, leads to saturation at fairly low reddening values with correspondingly gray attenuation functions. This makes the assessment of the attenuation of the far-UV flux from starburst galaxies difficult, if only UV/visual/near-IR data are available. Existing data for UV-selected starburst galaxies indicate a range of UV attenuation factors of 0-150. Our models reproduce the "Calzetti Attenuation Law", provided one adopts SMC-type dust and a clumpy shell-type dust distribution surrounding the starbursts. The average far-UV attenuation factor for the Calzetti sample is found to be 7.4. The only relatively reliable measure for the UV attenuation factor for single galaxies was found in the ratio of the integrated far-IR flux to the far-UV flux, measured near 1600 A, requiring the measurement of the entire spectral energy distribution of galaxies.

  15. Soft versus hard X-ray emission in active galactic nuclei: partial-covering and warm-plus-cold absorber models

    NASA Astrophysics Data System (ADS)

    Ceballos, M. T.; Barcons, X.

    1996-09-01

    We analyse the ROSAT Position Sensitive Proportional Counter (PSPC) hardness ratio and the 0.5-2-keV to 2-10-keV flux ratio of 65 active galactic nuclei (AGN) for which there are both ROSAT archival observations available and 2-10-keV fluxes, mostly from the HEAO-1 MC-LASS survey. We conclude that the simplest spectral model for the AGN that can accommodate the variety of X-ray colours obtained is a standard power law (with energy spectral index alpha~0.9) plus a ~0.1-keV blackbody, both of which are partially absorbed. In our sample, type 1 AGN require an absorbing column around 10^22 cm^-2 with covering fractions between 20 and 100 per cent, while type 2 AGN display larger columns and ~100 per cent coverage. This simple model also provides a good link between soft and hard AGN X-ray luminosity functions and source counts. We also consider a warm absorber as an alternative model to partial covering and find that the presence of gas in two phases (ionized and neutral) is required.

  16. Dust Extinction and Emission in a Clumpy Galactic Disk. An Application of the Radiative Transfer Code TRADING

    E-print Network

    Simone Bianchi

    2008-07-24

    AIMS: I present the Monte Carlo radiative transfer code TRADING (Transfer of RAdiation through Dust In Galaxies). The code computes self-consistently the extinction of radiation in a dusty medium (including absorption and scattering) and the dust emission. METHODS: A binary-tree adaptive grid is used for the description of the dust distribution. Dust radiation is computed at thermal equilibrium or under stochastic heating condition, for a distribution of grains of different radii and materials. The code is applied to the case of a clumpy galactic disk, including both diffuse dust and a distribution of spherical clouds modelled on the GMCs of local galaxies. Diffuse and localised sources of starlight are used, with independent spectra. RESULTS: A model is provided for the edge-on galaxy NGC 891. The SED of the galaxy from the UV to the submm/mm range can be well reproduced by: a bulge/disk configuration of old stars together with an extended dust disk, as suggested by the analysis of optical/near-infrared images; a clumpy dust distribution of the same mass as the diffuse dust disk, together with a UV emitting component, half of which in the form of a diffuse disk and half in sources embedded in clouds. In total, it is found that about 35% of the bolometric radiation is absorbed (and emitted) by dust; and that absorption of starlight from the old population contributes to about 60% of the dust emission. A significant component of the dust emission from clouds is due to absorption of diffuse radiation. Radial profiles of dust emission in a clumpy disk are almost independent of the wavelength, with the exception of the wavelength range on the Wien side of the thermal equilibrium peak.

  17. Shock absorber

    Microsoft Academic Search

    G. F. Kalb; D. M. Brown

    1987-01-01

    A shock absorber is described for a wireline instrument for use in a liquid containing well to reduce sock if the instrument impacts on an object while being lowered, the shock absorber comprising: a sleeve, having an inner surface; a mandrel, telescopically movable within the sleeve from an outward extended position to an inward retracted position if a sufficient impact

  18. Absorb & Repel

    NSDL National Science Digital Library

    Kohl Children's Museum

    2012-01-01

    In this activity, learners investigate how different materials repel or absorb water. Learners use spray bottles to explore how everyday items like sponges, cardboard, feathers, etc. respond to water differently. This activity also introduces learners to the scientific method as learners make predictions about which materials will absorb or repel water.

  19. Supersonic flow through clumpy environments: simulations and experiments

    NASA Astrophysics Data System (ADS)

    Douglas, M. R.; Wilde, B. H.; Blue, B. E.; Hansen, J. F.; Foster, J. M.; Rosen, P. A.; Williams, R. J. R.; Hartigan, P.; Frank, A.

    2009-11-01

    Over the past decade, high resolution images of a number of Herbig-Haro objects using the Hubble Space Telescope have revealed complex, chaotic, evolving morphologies of bow shocks, knots, and filamentary structure. Such morphologies are likely a consequence of internal and terminal working surfaces moving into a medium that is highly inhomogeneous. To investigate how inhomogeneities play a role in shaping the morphology of such objects, laboratory experiments have been proposed to examine bow shock evolution as it propagates through a clumpy environment and subsequent development of small scale structure after shock passage. The experiments will be carried out at the Omega Laser Facility utilizing an existing platform which launches a near planar shock into an RF (C15H12O4) cylinder. Two types of downstream targets will be embedded in the RF cylinder: a clumpy target consisting of a 1mm-diameter RF foam sphere containing ˜ 47 randomly distributed 127-?m diameter ruby microspheres, and a 1 mm-diameter sphere target of ``uniformly'' mixed RF foam with sapphire nanopowder. Calculations pertaining to the experimental configuration will be presented and compared to experimental data, if available.

  20. Polarization of Dust Emission in Clumpy Molecular Clouds and Cores

    E-print Network

    T. J. Bethell; A. Chepurnov; A. Lazarian; J. Kim

    2006-11-10

    Grain alignment theory has reached the stage where quantitative predictions of the degree of alignment and its variations with optical depth are possible. With the goal of studying the effect of clumpiness on the sub-millimeter and far infrared polarization we computed the polarization due to alignment via radiative torques within clumpy models of cores and molecular clouds. Our models were based upon a highly inhomogeneous simulation of compressible magnetohydrodynamic turbulence. The P-I relations for our models reproduce those seen in observations. We show that the degree of polarization observed is extremely sensitive to the upper grain size cut-off, and is less sensitive to changes in the radiative anisotropy. Furthermore, despite a variety of dust temperatures along a single line of sight through our core and amongst dust grains of different sizes, the assumption of isothermality amongst the aligned grains does not introduce a significant error. Our calculations indicate that sub-mm polarization vectors can be reasonably good tracers for the underlying magnetic field structure, even for relatively dense clouds (A_V~10 to the cloud center). The current predictive power of the grain alignment theory should motivate future polarization observations using the next generation of multi-wavelength sub-mm polarimeters such as those proposed for SOFIA.

  1. Transition from Clumpy to Smooth Angular Diameter Distances

    E-print Network

    Eric V. Linder

    1997-10-29

    Distance relations in a locally inhomogeneous universe are expected to behave like the Dyer-Roeder solution on small angular scales and the Friedmann-Robertson-Walker solution on large angular scales. Within a simple compact clump model the transition between these asymptotic behaviors is demonstrated and quantified. The redshift dependent transition scale is of order a few arcseconds; this implies it should have little influence on large angular scale cosmological tests such as the volume-redshift relation but possibly significant effects on arcsecond angular diameter measurements of radio galaxies and AGNs. For example, at $z=2$ on arcsecond scales a clumpy flat universe mimics the angular diameter distance of a smooth $\\Omega=0.27$ model.

  2. Absorbed radiation dose on LHC interconnects

    E-print Network

    Versaci, R; Vlachoudis, V; CERN. Geneva. ATS Department

    2011-01-01

    Here we present the results of our FLUKA simulations devoted to the evaluation of the peak dose absorbed by the busbar insulator in the LHC Interaction Region 7 interconnects. The peak dose absorbed by the cold magnet coils are also presented.

  3. How Cold Is Cold?

    NSDL National Science Digital Library

    Richard Konicek-Moran

    2008-04-01

    Heat and cold are often difficult concepts for children to understand. First, our everyday sloppy language gives them a predisposition to such common misconceptions as cold being a substance that moves from place to place. Our colloquial language often re

  4. Analytical Approximations for Calculating the Escape and Absorption of Radiation in Clumpy Dusty Environments

    Microsoft Academic Search

    Frank Városi; Eli Dwek

    1999-01-01

    We present analytical approximations for calculating the scattering, absorption, and escape of nonionizing photons from a spherically symmetric two-phase clumpy medium, with either a central point source of isotropic radiation, a uniform distribution of isotropic emitters, or uniformly illuminated by external sources. The analytical approximations are based on the mega-grains model of two-phase clumpy media, as proposed by Hobson &

  5. Laboratory experiments of supersonic flows through clumpy environments

    NASA Astrophysics Data System (ADS)

    Douglas, M. R.; Wilde, B. H.; Blue, B. E.; Hansen, J. F.; Foster, J. M.; Rosen, P. A.; Williams, R. J. R.; Hartigan, P.; Frank, A.

    2010-11-01

    Supersonic flows through heterogeneous environments are common in astrophysics as evidenced by high resolution Hubble Space Telescope images of a variety of astrophysical objects, including supernova remnants and stellar jets. In many instances, the imaged flows exhibit a complex morphology consisting of multiple clumps, bow shocks, and filamentary structure extending over a range of spatial scales. To gain a better understanding of the dynamics occurring in such multi-clump flows, scaled laboratory experiments are being carried out at the Omega Laser Facility. In these experiments, a laser pulse is used to heat a halfraum to indirectly drive a near planar shock through a target that typically consists of many small dense spheres embedded in lower density foam. The evolution of the target is then imaged using x-ray radiography. Targets have been designed to span the parameter space of clump number and clump size distribution, as well as investigate the quantitative differences in shock propagation through a clumpy target with that of a uniform target of the same average density. An overview of the experiments and comparison with simulations will be presented.

  6. Full calculation of clumpiness boost factors for antimatter cosmic rays in the light of LambdaCDM N-body simulation results. Abandoning hope in clumpiness enhancement?

    Microsoft Academic Search

    J. Lavalle; Q. Yuan; D. Maurin; X.-J. Bi

    2008-01-01

    Context: Anti-proton and positron Galactic cosmic ray spectra are among the key targets for indirect detection of dark matter. The boost factors, corresponding to an enhancement of the signal, and linked to the clumpiness properties of the dark matter distribution, have been taken as high as thousands in the past. The dramatic impact of these boost factors for indirect detection

  7. The clumpy structure of the chemically active L1157 outflow

    E-print Network

    Milena Benedettini; Serena Viti; Claudio Codella; Rafael Bachiller; Frederic Gueth; Maria T. Beltràn; Anne Dutrey; Stephane Guilloteau

    2007-08-01

    We present high spatial resolution maps, obtained with the Plateau de Bure Interferometer, of the blue lobe of the L1157 outflow. We observed four lines at 3 mm, namely CH3OH (2_K-1_K), HC3N (11-10), HCN (1-0) and OCS (7-6). Moreover, the bright B1 clump has also been observed at better spatial resolution in CS (2-1), CH3OH (2_1-1_1)A-, and 34SO (3_2-2_1). These high spatial resolution observations show a very rich structure in all the tracers, revealing a clumpy structure of the gas superimposed to an extended emission. In fact, the three clumps detected by previous IRAM-30m single dish observations have been resolved into several sub-clumps and new clumps have been detected in the outflow. The clumps are associated with the two cavities created by two shock episodes driven by the precessing jet. In particular, the clumps nearest the protostar are located at the walls of the younger cavity with a clear arch-shape form while the farthest clumps have slightly different observational characteristics indicating that they are associated to the older shock episode. The emission of the observed species peaks in different part of the lobe: the east clumps are brighter in HC3N (11-10), HCN (1-0) and CS (2-1) while the west clumps are brighter in CH3OH(2_K-1_K), OCS (7-6) and 34SO (3_2-2_1). This peak displacement in the line emission suggests a variation of the physical conditions and/or the chemical composition along the lobe of the outflow at small scale, likely related to the shock activity and the precession of the outflow. In particular, we observe the decoupling of the silicon monoxide and methanol emission, common shock tracers, in the B1 clump located at the apex of the bow shock produced by the second shock episode.

  8. Monte-Carlo Simulations of Linear Polarization in Clumpy OB-Star Winds

    E-print Network

    Townsend, Richard

    Monte-Carlo Simulations of Linear Polarization in Clumpy OB-Star Winds Rich Townsend & Nick Mast] Hamann W.-R., Feldmeier A., & Oskinova L. 2007, eds., Clumping in Hot-Star Winds: Proceedings, 9, 558 [4] Cohen D. H., Leutenegger M. A., & Townsend R. H. D. 2007, in [1], p. 209 [5] Yusef

  9. Perfect Metamaterial Absorber

    Microsoft Academic Search

    N. I. Landy; S. Sajuyigbe; J. J. Mock; D. R. Smith; W. J. Padilla

    2008-01-01

    We present the design for an absorbing metamaterial (MM) with near unity absorbance A(omega). Our structure consists of two MM resonators that couple separately to electric and magnetic fields so as to absorb all incident radiation within a single unit cell layer. We fabricate, characterize, and analyze a MM absorber with a slightly lower predicted A(omega) of 96%. Unlike conventional

  10. Ultrasensitive cold-electron bolometer

    Microsoft Academic Search

    Ian Jasper Ayagan Agulo

    2007-01-01

    The Cold-Electron Bolometer (CEB) is an ultrasensitive device designed for the detection of cosmic microwave background radiation. The key to its sensitivity is the electron cooling of the absorber by the superconductor-insulator-normal metal (SIN) tunnel junction. At a voltage near and below the superconducting gap, the electrons in the absorber are cooled well below the phonon temperature of the normal

  11. Modeling optical and UV polarization of AGNs III. From uniform-density to clumpy regions

    E-print Network

    Marin, F; Gaskell, C M

    2015-01-01

    A growing body of evidence suggests that part of, if not all, scattering regions of active galactic nuclei (AGNs) are clumpy. Hence. in this paper, we run radiative transfer models in the optical/UV for a variety of AGN reprocessing regions with different distributions of clumpy scattering media. We use the latest version of the Monte Carlo code STOKES presented in the first two papers of this series to model AGN reprocessing regions of increasing morphological complexity. We replace previously uniform-density media with up to thousands of constant-density clumps. We couple a continuum source to fragmented equatorial scattering regions, polar outflows, and toroidal, obscuring dust regions and investigate a wide range of geometries. We also consider different levels of fragmentation in each scattering region to evaluate importance of fragmentation for the net polarization of the AGN. We find that, in comparison with uniform-density models, equatorial distributions of gas and dust clouds result in grayer spectr...

  12. Unbiased constraints on the clumpiness of the Universe from standard candles

    NASA Astrophysics Data System (ADS)

    Li, Zhengxiang; Ding, Xuheng; Zhu, Zong-Hong

    2015-04-01

    We perform unbiased tests for the clumpiness of the Universe by confronting the Zel'dovich-Kantowski-Dyer-Roeder luminosity distance, which describes the effect of local inhomogeneities on the propagation of light with the observational one estimated from measurements of standard candles, i.e., type Ia supernovae (SNe Ia) and gamma-ray bursts (GRBs). Methodologically, we first determine the light-curve fitting parameters which account for distance estimation in SNe Ia observations and the luminosity/energy relations which are responsible for distance estimation of GRBs in the global fit to reconstruct the Hubble diagrams in the context of a clumpy Universe. Subsequently, these Hubble diagrams allow us to achieve unbiased constraints on the matter density parameter ?m , as well as the clumpiness parameter ? which quantifies the fraction of homogeneously distributed matter within a given light cone. At a 1 ? confidence level, the constraints are ?m=0.34 ±0.02 and ? =1.0 0-0.02+0.00 from the joint analysis. The results suggest that the Universe full of Friedman-Lemaître-Robertson-Walker fluid is favored by observations of standard candles with very high statistical significance. On the other hand, they may also indicate that the Zel'dovich-Kantowski-Dyer-Roeder approximation is a sufficiently accurate form to describe the effects of local homogeneity on the expanding Universe.

  13. A Laboratory Investigation of Supersonic Clumpy Flows: Experimental Design and Theoretical Analysis

    E-print Network

    A. Y. Poludnenko; K. K. Dannenberg; R. P. Drake; A. Frank; J. Knauer; D. D. Meyerhofer; M. Furnish; J. R. Asay

    2003-05-09

    We present a design for high energy density laboratory experiments studying the interaction of hypersonic shocks with a large number of inhomogeneities. These ``clumpy'' flows are relevant to a wide variety of astrophysical environments including the evolution of molecular clouds, outflows from young stars, Planetary Nebulae and Active Galactic Nuclei. The experiment consists of a strong shock (driven by a pulsed power machine or a high intensity laser) impinging on a region of randomly placed plastic rods. We discuss the goals of the specific design and how they are met by specific choices of target components. An adaptive mesh refinement hydrodynamic code is used to analyze the design and establish a predictive baseline for the experiments. The simulations confirm the effectiveness of the design in terms of articulating the differences between shocks propagating through smooth and clumpy environments. In particular, we find significant differences between the shock propagation speeds in a clumpy medium compared to a smooth one with the same average density. The simulation results are of general interest for foams in both inertial confinement fusion and laboratory astrophysics studies. Our results highlight the danger of using average properties of inhomogeneous astrophysical environments when comparing timescales for critical processes such as shock crossing and gravitational collapse times.

  14. Diverse Galaxies: Clumpy Regions In The UVUDF at 0.5 ? z ? 1.5

    NASA Astrophysics Data System (ADS)

    Soto, Emmaris; de Mello, Duilia F.; Teplitz, Harry I.; Gardner, Jonathan P.; Bond, Nicholas A.; Rafelski, Marc; Ravindranath, Swara; Scarlata, Claudia; Codoreanu, Alex; Koekemoer, Anton M.; Kurczynski, Peter; Uvudf Team

    2015-01-01

    We present an investigation of clumpy galaxies using the deepest ultraviolet data in the Hubble Ultra Deep Field (HUDF) taken with Wide Field Camera 3 UVIS detector. We use 3 new post-flashed UV images taken with the F225W, F275W, and F336W filters. Here we present an analysis of all galaxies in the 0.5 to 1.5 redshift range. These galaxies show a variety of properties, with objects having just a single clump to galaxies littered with clumps. We perform an optical morphological study of ultraviolet-detected galaxies using a visual classification scheme similar to that employed by the Hubble CANDELS survey team. We find that the majority of the objects that are clumpy in the ultraviolet have optical morphologies that are disks, followed by irregulars. We measure galaxy luminosities in the rest-frame UV, clump sizes, and luminosities for each clump in 7 passbands from the UV to the optical. We find that the majority of these UV bright clumpy galaxies are classified as Scd and starburst spectral types and have clump sizes between 0.7 to 1.9 kpc. We quantify the contribution of the clumps to the global star formation rate of the galaxy.

  15. A Game of Hide and Seek: Expectations of Clumpy Resources Influence Hiding and Searching Patterns

    PubMed Central

    Wilke, Andreas; Minich, Steven; Panis, Megane; Langen, Tom A.; Skufca, Joseph D.; Todd, Peter M.

    2015-01-01

    Resources are often distributed in clumps or patches in space, unless an agent is trying to protect them from discovery and theft using a dispersed distribution. We uncover human expectations of such spatial resource patterns in collaborative and competitive settings via a sequential multi-person game in which participants hid resources for the next participant to seek. When collaborating, resources were mostly hidden in clumpy distributions, but when competing, resources were hidden in more dispersed (random or hyperdispersed) patterns to increase the searching difficulty for the other player. More dispersed resource distributions came at the cost of higher overall hiding (as well as searching) times, decreased payoffs, and an increased difficulty when the hider had to recall earlier hiding locations at the end of the experiment. Participants’ search strategies were also affected by their underlying expectations, using a win-stay lose-shift strategy appropriate for clumpy resources when searching for collaboratively-hidden items, but moving equally far after finding or not finding an item in competitive settings, as appropriate for dispersed resources. Thus participants showed expectations for clumpy versus dispersed spatial resources that matched the distributions commonly found in collaborative versus competitive foraging settings. PMID:26154661

  16. Composition for absorbing hydrogen

    DOEpatents

    Heung, Leung K. (Aiken, SC); Wicks, George G. (Aiken, SC); Enz, Glenn L. (N. Augusta, SC)

    1995-01-01

    A hydrogen absorbing composition. The composition comprises a porous glass matrix, made by a sol-gel process, having a hydrogen-absorbing material dispersed throughout the matrix. A sol, made from tetraethyl orthosilicate, is mixed with a hydrogen-absorbing material and solidified to form a porous glass matrix with the hydrogen-absorbing material dispersed uniformly throughout the matrix. The glass matrix has pores large enough to allow gases having hydrogen to pass through the matrix, yet small enough to hold the particles dispersed within the matrix so that the hydrogen-absorbing particles are not released during repeated hydrogen absorption/desorption cycles.

  17. Methods for absorbing neutrons

    DOEpatents

    Guillen, Donna P. (Idaho Falls, ID); Longhurst, Glen R. (Idaho Falls, ID); Porter, Douglas L. (Idaho Falls, ID); Parry, James R. (Idaho Falls, ID)

    2012-07-24

    A conduction cooled neutron absorber may include a metal matrix composite that comprises a metal having a thermal neutron cross-section of at least about 50 barns and a metal having a thermal conductivity of at least about 1 W/cmK. Apparatus for providing a neutron flux having a high fast-to-thermal neutron ratio may include a source of neutrons that produces fast neutrons and thermal neutrons. A neutron absorber positioned adjacent the neutron source absorbs at least some of the thermal neutrons so that a region adjacent the neutron absorber has a fast-to-thermal neutron ratio of at least about 15. A coolant in thermal contact with the neutron absorber removes heat from the neutron absorber.

  18. Externally tuned vibration absorber

    DOEpatents

    Vincent, Ronald J. (Latham, NY)

    1987-09-22

    A vibration absorber unit or units are mounted on the exterior housing of a hydraulic drive system of the type that is powered from a pressure wave generated, e.g., by a Stirling engine. The hydraulic drive system employs a piston which is hydraulically driven to oscillate in a direction perpendicular to the axis of the hydraulic drive system. The vibration absorbers each include a spring or other resilient member having one side affixed to the housing and another side to which an absorber mass is affixed. In a preferred embodiment, a pair of vibration absorbers is employed, each absorber being formed of a pair of leaf spring assemblies, between which the absorber mass is suspended.

  19. Cold streams: detectability, relation to structure and characteristics

    NASA Astrophysics Data System (ADS)

    Goerdt, Tobias

    2015-02-01

    Cold gas streaming along the dark-matter filaments of the cosmic web is predicted to be the major provider of resources for disc buildup and star formation in massive galaxies in the early universe. We use hydrodynamical simulations to study to what extent these cold streams are traceable in the extended circum-galactic environment of galaxies via Ly alpha emission, Ly alpha absorption and selected low ionisation metal absorption lines. We predict the strength of the absorption signal produced by the streams and find that it is consistent with observations in high redshift galaxies. The characteristics of the Ly alpha emission of our simulated galaxies are similar in luminosity, morphology and extent to the observed Ly alpha blobs, with distinct kinematic features. We analyse the characteristics of the cold streams in simulations and present scaling relations for the amount of infall, its velocity, distribution and its clumpiness and compare our findings with observations.

  20. Hot and Cold

    NSDL National Science Digital Library

    Oregon Museum of Science and Industry

    1997-01-01

    In this activity, learners explore temperature changes from chemical reactions by mixing urea with water in one flask and mixing calcium chloride with water in another flask. They observe that the urea flask gets cold and the calcium chloride flask gets hot. The main idea is that some chemical processes release heat energy and are exothermic, while some chemical processes absorb heat energy and are endothermic. This activity is currently used in the Nature of Matter Unit in OMSI's Chemistry Lab. Cost estimates are per 100 learners.

  1. A search for the CO line emission toward two clumpy irregular galaxies, Markarian 8 and 297

    NASA Astrophysics Data System (ADS)

    Sofue, Y.; Hasegawa, T.; Nakai, N.; Handa, T.; Hayashi, M.; Heidmann, J.

    A deep search for the 12CO line emission at 2.6 mm (J = 1-0) was made of two clumpy irregular galaxies using the 45-m telescope at Nobeyama. Upper limits to the column density of CO molecules of 1.3×1017cm-2 and 1.1×1017cm-2 were obtained toward the most active regions in Markarian 8 and 297, respectively. The ratio of CO mass to H I mass in these galaxies is about a factor of 5 smaller than that for our Galaxy. The quantities are compared with those for the star-bursting galaxy M82.

  2. Modeling optical and UV polarization of AGNs. III. From uniform-density to clumpy regions

    NASA Astrophysics Data System (ADS)

    Marin, F.; Goosmann, R. W.; Gaskell, C. M.

    2015-05-01

    Context. A growing body of evidence suggests that some, if not all, scattering regions of active galactic nuclei (AGNs) are clumpy. The inner AGN components cannot be spatially resolved with current instruments and must be studied by numerical simulations of observed spectroscopy and polarization data. Aims: We run radiative transfer models in the optical/UV for a variety of AGN reprocessing regions with different distributions of clumpy scattering media. We obtain geometry-sensitive polarization spectra and images to improve our previous AGN models and their comparison with the observations. Methods: We use the latest public version 1.2 of the Monte Carlo code stokes presented in the first two papers of this series to model AGN reprocessing regions of increasing morphological complexity. We replace previously uniform-density media with up to thousands of constant-density clumps. We couple a continuum source to fragmented equatorial scattering regions, polar outflows, and toroidal obscuring dust regions and investigate a wide range of geometries. We also consider different levels of fragmentation in each scattering region to evaluate the importance of fragmentation for the net polarization of the AGN. Results: In comparison with uniform-density models, equatorial distributions of gas and dust clouds result in grayer spectra and show a decrease in the net polarization percentage at all lines of sight. The resulting polarization position angle depends on the morphology of the clumpy structure, with extended tori favoring parallel polarization while compact tori produce orthogonal polarization position angles. In the case of polar scattering regions, fragmentation increases the net polarization unless the cloud filling factor is small. A complete AGN model constructed from the individual, fragmented regions can produce low polarization percentages (<2%), with a parallel polarization angle for observer inclinations up to 70° for a torus half opening angle of 60°. For type-2 viewing angles the polarization switches to perpendicular and rises to ~50%. Conclusions: Our modeling shows that the introduction of fragmented dusty tori significantly alters the resulting net polarization of an AGN. Comparison of our models to polarization observations of large AGN samples greatly favors geometrically compact clumpy tori over extended ones.

  3. Active Absorbers M. Rousseaua

    E-print Network

    Paris-Sud XI, Université de

    the theory for a point active absorber immersed in the anechoic field from a point source. This will apply with a plane wave. An extra oscillatory interference term occurs which should largely cancel in rooms due to the varying distances between all the source images and the absorber. Responses were measured in several rooms

  4. Multispectral metamaterial absorber.

    PubMed

    Grant, J; McCrindle, I J H; Li, C; Cumming, D R S

    2014-03-01

    We present the simulation, implementation, and measurement of a multispectral metamaterial absorber (MSMMA) and show that we can realize a simple absorber structure that operates in the mid-IR and terahertz (THz) bands. By embedding an IR metamaterial absorber layer into a standard THz metamaterial absorber stack, a narrowband resonance is induced at a wavelength of 4.3 ?m. This resonance is in addition to the THz metamaterial absorption resonance at 109 ?m (2.75 THz). We demonstrate the inherent scalability and versatility of our MSMMA by describing a second device whereby the MM-induced IR absorption peak frequency is tuned by varying the IR absorber geometry. Such a MSMMA could be coupled with a suitable sensor and formed into a focal plane array, enabling multispectral imaging. PMID:24690713

  5. CLUMPY: Jeans analysis, $\\gamma$-ray and neutrino fluxes from dark matter (sub-)structures

    E-print Network

    Bonnivard, Vincent; Nezri, Emmanuel; Charbonnier, Aldée; Combet, Céline; Maurin, David

    2015-01-01

    We present an update of the CLUMPY code for the calculation of the astrophysical J-factors (from dark matter annihilation/decay) for any Galactic or extragalactic dark matter halo including substructures: the concentration-mass relationship may now be drawn from a distribution, boost factors can include several levels of substructures, and triaxiality is a new option for dark matter haloes. This new version takes advantage of the cfitsio and HEALPix libraries to propose FITS output maps using the HEALPix pixelisation scheme. Skymaps for $\\gamma$-ray and neutrino signals from generic annihilation/decay spectra are now direct outputs of CLUMPY. Smoothing by a user-defined instrumental Gaussian beam is also possible. In addition to these improvements, the main novelty is the implementation of a Jeans analysis module, to obtain dark matter density profiles from kinematic data in relaxed spherical systems (e.g., dwarf spheroidal galaxies). The code is also interfaced with the GreAT toolkit designed for Markov Chai...

  6. CLUMPY: Jeans analysis, $?$-ray and neutrino fluxes from dark matter (sub-)structures

    E-print Network

    Vincent Bonnivard; Moritz Hütten; Emmanuel Nezri; Aldée Charbonnier; Céline Combet; David Maurin

    2015-06-25

    We present an update of the CLUMPY code for the calculation of the astrophysical J-factors (from dark matter annihilation/decay) for any Galactic or extragalactic dark matter halo including substructures: the concentration-mass relationship may now be drawn from a distribution, boost factors can include several levels of substructures, and triaxiality is a new option for dark matter haloes. This new version takes advantage of the cfitsio and HEALPix libraries to propose FITS output maps using the HEALPix pixelisation scheme. Skymaps for $\\gamma$-ray and neutrino signals from generic annihilation/decay spectra are now direct outputs of CLUMPY. Smoothing by a user-defined instrumental Gaussian beam is also possible. In addition to these improvements, the main novelty is the implementation of a Jeans analysis module, to obtain dark matter density profiles from kinematic data in relaxed spherical systems (e.g., dwarf spheroidal galaxies). The code is also interfaced with the GreAT toolkit designed for Markov Chain Monte Carlo analyses, from which probability density functions and credible intervals can be obtained for velocity dispersions, dark matter profiles, and J- factors.

  7. Evolution of the fraction of clumpy galaxies at 0.2 < z < 1.0 in the cosmos field

    SciTech Connect

    Murata, K. L. [Department of Particle and Astrophysical Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602 (Japan); Kajisawa, M. [Graduate School of Science and Engineering, Ehime University, Bunkyo-cho, Matsuyama 790-8577 (Japan); Taniguchi, Y.; Kobayashi, M. A. R.; Shioya, Y. [Research Center for Space and Cosmic Evolution, Ehime University, Bunkyo-cho, Matsuyama 790-8577 (Japan); Capak, P. [Spitzer Science Center, 314-6 Caltech, Pasadena, CA 91125 (United States); Ilbert, O. [Aix Marseille Université, CNRS, LAM (Laboratoire d'Astrophysique de Marseille), UMR 7326, F-13388 Marseille (France); Koekemoer, A. M. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Salvato, M. [Max Planck Institut für Plasma Physik and Excellence Cluster, D-85748 Garching (Germany); Scoville, N. Z., E-mail: murata.katsuhiro@g.mbox.nagoya-u.ac.jp [California Institute of Technology, MC 249-17, 1200 East California Boulevard, Pasadena, CA 91125 (United States)

    2014-05-01

    Using the Hubble Space Telescope/Advanced Camera for Surveys data in the COSMOS field, we systematically searched clumpy galaxies at 0.2 < z < 1.0 and investigated the fraction of clumpy galaxies and its evolution as a function of stellar mass, star formation rate (SFR), and specific SFR (SSFR). The fraction of clumpy galaxies in star-forming galaxies with M {sub star} > 10{sup 9.5} M {sub ?} decreases with time from ?0.35 at 0.8 < z < 1.0 to ?0.05 at 0.2 < z < 0.4, irrespective of the stellar mass, although the fraction tends to be slightly lower for massive galaxies with M {sub star} > 10{sup 10.5} M {sub ?} at each redshift. On the other hand, the fraction of clumpy galaxies increases with increasing both SFR and SSFR in all the redshift ranges we investigated. In particular, we found that the SSFR dependences of the fractions are similar among galaxies with different stellar masses, and the fraction at a given SSFR does not depend on the stellar mass in each redshift bin. The evolution of the fraction of clumpy galaxies from z ? 0.9 to z ? 0.3 seems to be explained by such SSFR dependence of the fraction and the evolution of SSFRs of star-forming galaxies. The fraction at a given SSFR also appears to decrease with time, but this can be due to the effect of the morphological k correction. We suggest that these results are understood by the gravitational fragmentation model for the formation of giant clumps in disk galaxies, where the gas mass fraction is a crucial parameter.

  8. Sub-millimeter Galaxies: Dusty, Clumpy and Messy Starbursts in the Distant Universe

    NASA Astrophysics Data System (ADS)

    Menéndez-Delmestre, K.; Blain, A. W.; Swinbank, M.; Smail, I.; Ivison, R.; Chapman, S. C.; Gonçalves, T. S.

    2014-10-01

    We present the first spatially-resolved observations of the H? emission in three z˜2 sub-millimeter selected galaxies (SMGs) using the Keck OH-Suppressing Infrared Imaging Spectrograph (OSIRIS) with Laser Guide Star Adaptive Optics (LGS-AO). With the unprecedent kpc-scale resolution - up to ten times that achieved with previous seeing-limited studies - and the kinematic insight that these observations provide, we unveil a clumpy H? structure and reveal velocity offsets that suggest these systems are in an advanced merging phase. The spatially-resolved spectral information also allows us to disentangle the H? emission arising from an active galactic nucleus (AGN) from that associated with star formation.

  9. Clumpy Langmuir waves in type III radio sources - Comparison of stochastic-growth theory with observations

    NASA Technical Reports Server (NTRS)

    Robinson, P. A.; Cairns, I. H.; Gurnett, D. A.

    1993-01-01

    Detailed comparisons are made between the Langmuir-wave properties predicted by the recently developed stochastic-growth theory of type III sources and those observed by the plasma wave experiment on ISEE 3, after correcting for the main instrumental and selection effects. Analysis of the observed field-strength distribution confirms the theoretically predicted form and implies that wave growth fluctuates both spatially and temporally in sign and magnitude, leading to an extremely clumpy distribution of fields. A cutoff in the field-strength distribution is seen at a few mV/m, corresponding to saturation via nonlinear effects. Analysis of the size distribution of Langmuir clumps yields results in accord with those obtained in earlier work and with the size distribution of ambient density fluctuations in the solar wind. This confirms that the inhomogeneities in the Langmuir growth rate are determined by the density fluctuations and that these fluctuations persist during type III events.

  10. Shock absorber servicing tool

    NASA Technical Reports Server (NTRS)

    Koepler, Jack L. (Inventor); Hill, Robert L. (Inventor)

    1981-01-01

    A tool to assist in the servicing of a shock absorber wherein the shock absorber is constructed of a pair of aligned gas and liquid filled chambers. Each of the chambers is separated by a movable separator member. Maximum efficiency of the shock absorber is achieved in the locating of a precise volume of gas within the gas chamber and a precise volume of liquid within the liquid chamber. The servicing tool of this invention employs a rod which is to connect with the separator and by observation of the position of the rod with respect to the gauge body, the location of the separator is ascertained even though it is not directly observable.

  11. Mechanical energy absorber

    NASA Astrophysics Data System (ADS)

    Wesselski, Clarence J.

    1995-06-01

    An energy absorbing system for controlling the force where a moving object engages a stationary stop and where the system utilized telescopic tubular members, energy absorbing diaphragm elements, force regulating disc springs, and a return spring to return the telescoping member to its start position after stroking is presented. The energy absorbing system has frusto-conical diaphragm elements frictionally engaging the shaft and are opposed by a force regulating set of disc springs. In principle, this force feedback mechanism serves to keep the stroking load at a reasonable level even if the friction coefficient increases greatly. This force feedback device also serves to desensitize the singular and combined effects of manufacturing tolerances, sliding surface wear, temperature changes, dynamic effects, and lubricity.

  12. Mechanical energy absorber

    NASA Astrophysics Data System (ADS)

    Wesselski, Clarence J.

    1993-07-01

    An energy absorbing system for controlling the force where a moving object engages a stationary stop and where the system utilized telescopic tubular members, energy absorbing diaphragm elements, force regulating disc springs, and a return spring to return the telescoping member to its start position after stroking is presented. The energy absorbing system has frusto-conical diaphragm elements frictionally engaging the shaft and are opposed by a force regulating set of disc springs. In principle, this force feedback mechanism serves to keep the stroking load at a reasonable level even if the friction coefficient increases greatly. This force feedback device also serves to desensitize the singular and combined effects of manufacturing tolerances, sliding surface wear, temperature changes, dynamic effects, and lubricity.

  13. Multiple-layer Radiation Absorber

    NASA Astrophysics Data System (ADS)

    Baker, Robert M. L.; Baker, Bonnie Sue

    A structure is discussed for absorbing incident radiation, either electromagnetic (EM) or sound. Such a surface structure is needed, for example, in a highly sensitive high-frequency gravitational wave or HFGW detector such as the Li-Baker. The multi-layer absorber, which is discussed, is constructed with metamaterial [MM] layer or layers on top. This MM is configured for a specific EM or sound radiation frequency band, which absorbs incident EM or sound radiation without reflection. Below these top MM layers is a substrate of conventional EM-radiation absorbing or acoustical absorbing reflective material, such as an array of pyramidal foam absorbers. Incident radiation is partially absorbed by the MM layer or layers, and then it is more absorbed by the lower absorbing and reflecting substrate. The remaining reflected radiation is even further absorbed by the MM layers on its "way out_ so that essentially all of the incident radiation is absorbed _ a nearly perfect black-body absorber. In a HFGW detector a substrate, such as foam absorbers, may outgas into a high vacuum and reduce the capability of the vacuum-producing equipment, however, the layers above this lowest substrate will seal the absorbing and reflecting substrate from any external vacuum. The layers also serve to seal the absorbing material against air or water flow past the surfaces of aircraft, watercraft or submarines. Other applications for such a multiple-level radiation absorber include stealth aircraft, missiles and submarines.

  14. Polypyrrole Based Microwave Absorbers

    Microsoft Academic Search

    V.-T. Truong; S. Z. Riddell; R. F. Muscat

    1998-01-01

    Reflection of microwave radiations from single layer and two-layer materials is calculated. Microwave absorbing materials are formulated by mixing a commercially available paint or rubber with the conducting polypyrrole (PPy) powder. The reflection loss strongly depends on thickness and complex permittivity of the material. For a single layer material, optimum values of the real part, ?', and imaginary part, ?'',

  15. Shock Absorbing Helmets

    NASA Technical Reports Server (NTRS)

    1978-01-01

    This paper presents a description of helmets used by football players that offer three times the shock-absorbing capacity of earlier types. An interior padding for the helmets, composed of Temper Foam, first used by NASA's Ames Research Center in the design of aircraft seats is described.

  16. Internal absorber solar collector

    Microsoft Academic Search

    S. B. Herskovitz; F. S. Holt; C. J. Sletten; E. J. Sletten

    1981-01-01

    Thin solar collecting panels are described made from arrays of small rod collectors consisting of a refracting dielectric rod lens with an absorber imbedded within it and a reflecting mirror coated on the back side of the dielectric rod. Non-tracking collector panels on vertical walls or roof tops receive approximately 90% of solar radiation within an acceptance zone 60° in

  17. Internal absorber solar collector

    Microsoft Academic Search

    Carlyle J. Sletten; Sheldon B. Herskovitz; F. S. Holt; E. J. Sletten

    1981-01-01

    Thin solar collecting panels are described made from arrays of small rod collectors consisting of a refracting dielectric rod lens with an absorber imbedded within it and a reflecting mirror coated on the back side of the dielectric rod. Non-tracking collector panels on vertical walls or roof tops receive approximately 90% of solar radiation within an acceptance zone 60.degree. in

  18. Common Cold

    MedlinePLUS

    ... en español] National Library of Medicine, Medline Plus ? Common Cold Skip Content Marketing Share this: JavaScript is disabled in your browser. To view this content, please enable JavaScript and refresh the page. Click here for instructions on how to enable JavaScript in your browser. ...

  19. Cold Sores

    MedlinePLUS

    ... causes oral herpes, or cold sores. Type 1 herpes virus infects more than half of the U.S. population by the time they reach their 20s. Type 2 usually affects the genital area Some people have no symptoms from the ...

  20. Cold War

    NSDL National Science Digital Library

    Cold War is a major, 24-part series directed by renowned documentary filmmaker Jeremy Isaacs that recently premiered on CNN and BBC2. Whether or not this series will become "the definitive account of the Cold War" remains to be seen, but the research that has made it possible is quite impressive. This feature-filled, comprehensive site complements the series by offering, among other things, video previews and multimedia recaps of each episode; video, audio, and text excerpts from nearly 100 interviews filmed for the series; text from archival documents and contemporaneous Time and Russian newspaper stories; in-depth sections on Cold War culture; and a Knowledge Bank section containing a glossary, "Cold Warrior" profiles, related links, and a chronology. Additional resources include a classroom guide to the series, online Shockwave quiz games, and an online discussion group. As large as it is now, the site will continue to expand and add new features as the series progresses over the next three months.

  1. Cold Water Vapor in the Barnard 5 Molecular Cloud

    NASA Technical Reports Server (NTRS)

    Wirstrom, E. S.; Charnley, S. B.; Persson, C. M.; Buckle, J. V.; Cordiner, M. A.; Takakuwa, S.

    2014-01-01

    After more than 30 yr of investigations, the nature of gas-grain interactions at low temperatures remains an unresolved issue in astrochemistry. Water ice is the dominant ice found in cold molecular clouds; however, there is only one region where cold ((is) approximately 10 K) water vapor has been detected-L1544. This study aims to shed light on ice desorption mechanisms under cold cloud conditions by expanding the sample. The clumpy distribution of methanol in dark clouds testifies to transient desorption processes at work-likely to also disrupt water ice mantles. Therefore, the Herschel HIFI instrument was used to search for cold water in a small sample of prominent methanol emission peaks. We report detections of the ground-state transition of o-H2O (J = 110-101) at 556.9360 GHz toward two positions in the cold molecular cloud, Barnard 5. The relative abundances of methanol and water gas support a desorption mechanism which disrupts the outer ice mantle layers, rather than causing complete mantle removal.

  2. Ionized Absorbers in AGN

    NASA Technical Reports Server (NTRS)

    Mathur, S.

    1999-01-01

    As a part of this program, we observed three AGN:PKS2251 + 113, PG0043 = 039 and PLH909. Two objects show signatures of absorbtion in their UV spectra. Based on our earlier modeling of X-ray warm absorbents, we expected to observe X-ray observation in these objects. The third, PLH909, is known to have soft excess in EINSTEIN data. Attachment: "Exploratory ASCA observation of broad absorption line quasi-stellar objects".

  3. Apollo couch energy absorbers

    NASA Technical Reports Server (NTRS)

    Wesselski, C. J.; Drexel, R. E.

    1972-01-01

    Load attenuators for the Apollo spacecraft crew couch and its potential applications are described. Energy absorption is achieved through friction and cyclic deformation of material. In one concept, energy absorption is accomplished by rolling a compressed ring of metal between two surfaces. In another concept, energy is absorbed by forcing a plastically deformed washer along a rod. Among the design problems that had to be solved were material selection, fatigue life, ring slippage, lubrication, and friction loading.

  4. Cold agglutination.

    PubMed

    Roelcke, D

    1989-04-01

    Autoantibodies against red cells optimally reacting at 0 degree C, ie, CA, are normally found with low titers in the serum of human adults. High-titer CA may be induced by certain infectious agents, including M pneumoniae, EBV, CMV, and rubella virus, or may develop on the basis of chronic (malignant) B cell lymphoproliferation. The main clinical manifestation of cold agglutination is AIHA. Antigens and antibodies of cold agglutination are the best characterized reaction partners of a human autoimmune process. CA may recognize I and i antigens, which are lipid- and protein-linked branched and linear N-acetyl-lactosamine chains, respectively. They are precursors of the ABH blood group antigens and are converted into H by fucosylation. An alternative substitution by sialylation creates Gd, Fl, and probably Vo/Li antigens. CA with anti-Pr and anti-Sa specificities recognize 0-glycans with immunodominant sialyl groups on glycophorins. Several Pr subspecificities can be identified by chemically modified sialyl groups on glycophorins. Because CA in chronic lymphoproliferation are monoclonal antibodies, structure-specificity-interrelations of the antibodies could be identified by primary structure analyses of the N-terminal variable regions of H and L chains and by studies on CA idiotypes. Interrelations between distinct CA specificities and particular infectious agents could explain cold agglutination as a response to receptors for the agents or to the binding sites of antibodies against the agents. Interrelations also existing between certain CA isotypes (Ig classes and L chain types) and CA specificities could be a basis for the elucidation of the enigmatic etiology of chronic (malignant) monoclonal cold agglutination. PMID:2520550

  5. Laboratory experiments to study supersonic astrophysical flows interacting with clumpy environments

    NASA Astrophysics Data System (ADS)

    Rosen, P. A.; Foster, J. M.; Wilde, B. H.; Hartigan, P.; Blue, B. E.; Hansen, J. F.; Sorce, C.; Williams, R. J. R.; Coker, R.; Frank, A.

    2009-08-01

    A wide variety of objects in the universe drive supersonic outflows through the interstellar medium which is often highly clumpy. These inhomogeneities affect the morphology of the shocks that are generated. The hydrodynamics are difficult to model as the problem is inherently 3D and the clumps are subject to a variety of fluid instabilities as they are accelerated and destroyed by the shock. Over the last two years, we have been carrying out experiments at the University of Rochester’s Omega laser to address the interaction of a dense-plasma jet with a localised density perturbation. More recently, we have turned our attention to the interaction of a shock wave with a spherical particle. We use a 1.6-mm diameter, 1.2-mm length Omega hohlraum to drive a composite plastic ablator (which includes bromine to prevent M-band radiation from preheating the experiment). The ablator acts as a “piston” driving a shock into 0.3 g cm-3 foam containing a 0.5-mm diameter sapphire sphere. We radiograph along two orthogonal lines of sight, using nickel or zinc pinhole-apertured X-ray backlighters, to study the subsequent hydrodynamics. We present initial experimental results and two-dimensional simulations of the experiment.

  6. Magnification Probability Distribution Functions of Standard Candles in a Clumpy Universe

    E-print Network

    Chul-Moon Yoo; Hideki Ishihara; Ken-ichi Nakao; Hideyuki Tagoshi

    2008-11-28

    Lensing effects on light rays from point light sources, such like Type Ia supernovae, are simulated in a clumpy universe model. In our universe model, it is assumed that all matter in the universe takes the form of randomly distributed objects each of which has finite size and is transparent for light rays. Monte-Carlo simulations are performed for several lens models, and we compute probability distribution functions of magnification. In the case of the lens models that have a smooth density profile or the same degree of density concentration as the spherical NFW (Navarro-Frenk-White) lens model at the center, the so-called gamma distributions fit well the magnification probability distribution functions if the size of lenses is sufficiently larger than the Einstein radius. In contrast, the gamma distributions do not fit the magnification probability distribution functions in the case of the SIS (Singular Isothermal Sphere) lens model. We find, by using the power law cusp model, that the magnification probability distribution function is fitted well using the gamma distribution only when the slope of the central density profile is not very steep. These results suggest that we may obtain information about the slope of the central density profiles of dark matter halo from the lensing effect of Type Ia supernovae.

  7. Orbital decay of supermassive black hole binaries in clumpy multiphase merger remnants

    NASA Astrophysics Data System (ADS)

    Roškar, Rok; Fiacconi, Davide; Mayer, Lucio; Kazantzidis, Stelios; Quinn, Thomas R.; Wadsley, James

    2015-05-01

    We simulate an equal-mass merger of two Milky Way-size galaxy discs with moderate gas fractions at parsec-scale resolution including a new model for radiative cooling and heating in a multiphase medium, as well as star formation and feedback from supernovae. The two discs initially have a 2.6 × 106 M? supermassive black hole (SMBH) embedded in their centres. As the merger completes and the two galactic cores merge, the SMBHs form a pair with a separation of a few hundred pc that gradually decays. Due to the stochastic nature of the system immediately following the merger, the orbital plane of the binary is significantly perturbed. Furthermore, owing to the strong starburst the gas from the central region is completely evacuated, requiring ˜10 Myr for a nuclear disc to rebuild. Most importantly, the clumpy nature of the interstellar medium has a major impact on the dynamical evolution of the SMBH pair, which undergo gravitational encounters with massive gas clouds and stochastic torquing by both clouds and spiral modes in the disc. These effects combine to greatly delay the decay of the two SMBHs to separations of a few parsecs by nearly two orders of magnitude, ˜108 yr, compared to previous work. In mergers of more gas-rich, clumpier galaxies at high redshift stochastic torques will be even more pronounced and potentially lead to stronger modulation of the orbital decay. This suggests that SMBH pairs at separations of several tens of parsecs should be relatively common at any redshift.

  8. Corrosion resistant neutron absorbing coatings

    DOEpatents

    Choi, Jor-Shan; Farmer, Joseph C; Lee, Chuck K; Walker, Jeffrey; Russell, Paige; Kirkwood, Jon; Yang, Nancy; Champagne, Victor

    2013-11-12

    A method of forming a corrosion resistant neutron absorbing coating comprising the steps of spray or deposition or sputtering or welding processing to form a composite material made of a spray or deposition or sputtering or welding material, and a neutron absorbing material. Also a corrosion resistant neutron absorbing coating comprising a composite material made of a spray or deposition or sputtering or welding material, and a neutron absorbing material.

  9. Baltic Astronomy, vol. 20, 490494, 2011 AGN DUSTY TORI AS A CLUMPY TWO-PHASE MEDIUM

    E-print Network

    Baes, Maarten

    surrounding the central engine of an active galactic nucleus (AGN), absorbs the incoming radiation a multi-phase filamentary (sponge-like) structure, rather then isolated clumps. We took a step further

  10. Imaging the outward motions of clumpy dust clouds around the red supergiant Antares with VLT/VISIR

    NASA Astrophysics Data System (ADS)

    Ohnaka, K.

    2014-08-01

    Aims: We present a 0."5-resolution 17.7 ?m image of the red supergiant Antares. Our aim is to study the structure of the circumstellar envelope in detail. Methods: Antares was observed at 17.7 ?m with the VLT mid-infrared instrument VISIR. Taking advantage of the BURST mode, in which a large number of short exposure frames are taken, we obtained a diffraction-limited image with a spatial resolution of 0."5. Results: The VISIR image shows six clumpy dust clouds located at 0."8-1."8 (43-96 R? = 136-306 AU) away from the star. We also detected compact emission within a radius of 0."5 around the star. Comparison of our VISIR image taken in 2010 and the 20.8 ?m image taken in 1998 with the Keck Telescope reveals the outward motions of four dust clumps. The proper motions of these dust clumps (with respect to the central star) amount to 0."2-0."6 in 12 years. This translates into expansion velocities (projected onto the plane of the sky) of 13-40 km s-1 with an uncertainty of ± 7 km s-1. The inner compact emission seen in the 2010 VISIR image is presumably newly formed dust, because it is not detected in the image taken in 1998. If we assume that the dust is ejected in 1998, the expansion velocity is estimated to be 34 km s-1, in agreement with the velocity of the outward motions of the clumpy dust clouds. The mass of the dust clouds is estimated to be (3-6) × 10-9 M?. These values are lower by a factor of 3-7 than the amount of dust ejected in one year estimated from the (gas+dust) mass-loss rate of 2 × 10-6 M? yr-1, suggesting that the continuous mass loss is superimposed on the clumpy dust cloud ejection. Conclusions: The clumpy dust envelope detected in the 17.7 ?m diffraction-limited image is similar to the clumpy or asymmetric circumstellar environment of other red supergiants. The velocities of the dust clumps cannot be explained by a simple accelerating outflow, implying the possible random nature of the dust cloud ejection mechanism. Based on VISIR observations made with the Very Large Telescope of the European Southern Observatory. Program ID: 385.D-0120(A), 286.D-5007(A).

  11. Ubiquitous Variability of X-Ray-absorbing Column Densities in Seyfert 2 Galaxies

    NASA Astrophysics Data System (ADS)

    Risaliti, G.; Elvis, M.; Nicastro, F.

    2002-05-01

    We present a study of the variations in the absorbing column density of 25 X-ray-defined Seyfert 2 galaxies, as inferred from hard X-ray observations, on timescales from months to several years. We show that a significant variation of NH (from 20% to 80%) is observed in almost all (22 of 25) of the sources with multiple X-ray observations, although X-ray absorption never vanishes. For a subsample of 11 sources observed at least five times, the typical variation time, as defined by a structure function, is less than 1 yr for both heavily absorbed (NH~1023 cm-2) and moderately absorbed (NH~1022 cm-2) sources. These variations rule out the simplest version of the unified models, based on a homogeneous obscuring torus, and suggest the presence of clumpy circumnuclear material on a scale well below a parsec. We propose a modification of the torus model in which an overabundance of slightly dusty broad emission-line region (BELR) clouds obscures the BELR. The BELR needs, like the torus, to have an axisymmetric structure. This model is closely related to that of Elvis for type 1 active galactic nuclei (AGNs). For lightly obscured AGNs (NH~1022 cm-2), the structure function shows an increase at a timescale of ~5 yr, indicating a second absorber, most probably on a 5-10 pc scale associated with the host galaxy.

  12. Sensing with THz metamaterial absorbers

    E-print Network

    Cong, Longqing

    2014-01-01

    Metamaterial perfect absorbers from microwaves to optical part of the electromagnetic spectrum has been intensely studied for its ability to absorb electromagnetic radiation. Perfect absorption of light by metamaterials have opened up new opportunities for application oriented functionalities such as efficient sensors and emitters. We present an absorber based sensing scheme at the terahertz frequencies and discuss optimized designs to achieve high frequency and amplitude sensitivities. The major advantage of a perfect metamaterial absorber as a sensor is the sensitive shift in the absorber resonance frequency along with the sharp change in the amplitude of the resonance due to strong interaction of the analyte with the electric and the magnetic fields at resonant perfect absorption frequency. We compare the sensing performance of the perfect metamaterial absorber with its complementary structural design and planar metasurface with identical structure. The best FoM values obtained for the absorber sensor here...

  13. Common cold

    PubMed Central

    2011-01-01

    Introduction Each year, children suffer up to 5 colds and adults have two to three infections, leading to time off school or work, and considerable discomfort. Most symptoms resolve within 1 week, but coughs often persist for longer. Methods and outcomes We conducted a systematic review and aimed to answer the following clinical question: What are the effects of treatments for common cold? We searched: Medline, Embase, The Cochrane Library, and other important databases up to January 2010 (Clinical Evidence reviews are updated periodically, please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA). Results We found 21 systematic reviews and RCTs that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions. Conclusions In this systematic review we present information relating to the effectiveness and safety of the following interventions: analgesics or anti-inflammatory drugs, antibiotics, antihistamines, decongestants for short-term and for long-term relief, decongestants plus antihistamines, echinacea, steam inhalation, vitamin C, and zinc (intranasal gel or lozenges). PMID:21406124

  14. Metamaterial saturable absorber mirror.

    PubMed

    Dayal, Govind; Ramakrishna, S Anantha

    2013-02-01

    We propose a metamaterial saturable absorber mirror at midinfrared wavelengths that can show a saturation of absorption with intensity of incident light and switch to a reflecting state. The design consists of an array of circular metallic disks separated by a thin film of vanadium dioxide (VO(2)) from a continuous metallic film. The heating due to the absorption in the absorptive state causes the VO(2) to transit to a metallic phase from the low temperature insulating phase. The metamaterial switches from an absorptive state (R?0.1%) to a reflective state (R>95%) for a specific threshold intensity of the incident radiation corresponding to the phase transition of VO(2), resulting in the saturation of absorption in the metamaterial. The computer simulations show over 99.9% peak absorbance, a resonant bandwidth of about 0.8 ?m at 10.22 ?m wavelengths, and saturation intensity of 140 mW cm(-2) for undoped VO(2) at room temperature. We also carried out numerical simulations to investigate the effects of localized heating and temperature distribution by solving the heat diffusion problem. PMID:23381408

  15. Radiative transfer in a clumpy universe: The colors of high-redshift galaxies

    NASA Technical Reports Server (NTRS)

    Madau, Piero

    1995-01-01

    We assess the effects of the stochastic attenuation produced by intervening QSO absorption systems on the broadband colors of galaxies at cosmological distances. We compute the H I opacity of a clumpy universe as a function of redshift, including scattering in resonant lines, such as Lyman alpha, Lyman beta, Lyman gamma, and higher order members, and Lyman-continuum absorption. Both the numerous, optically thin Lyman-alpha forest clouds and the rarer, optically thick Lyman limit systems are found to contribute to the obscuration of background sources. We study the mean properties of primeval galaxies at high redshift in four broad optical passbands, U(sub n), B, G, and R. Even if young galaxies radiated a significant amount of ionizing photons, the attenuation due to the accumulated photoelectric opacity along the path is so severe that sources beyond z approximately 3 will drop out of the U(sub n) image together. We also show that the observed B-R color of distant galaxies can be much redder than expected from a stellar population. At z approximately 3.5, the blanketing by discrete absorption lines in the Lyman series is so effective that background galaxies appear, on average, 1 mag fainter in B. By z approximately 4, the observed B magnitude increment due to intergalactic absorption exceeds 2 mag. By modeling the intrinsic UV spectral energy distribution of star-forming galaxies with a stellar population synthesis code, we show that the (B-R)(sub AB) approximately 0 criterion for identifying 'flat-spectrum,' metal-producing galaxies is biased against objects at z greater than 3. The continuum blanketing from the Lyman series produces a characteristic staircase profile in the transmitted power. We suggest that this cosmic Lyman decrement might be used as a tool to identify high-z galaxies.

  16. MAPPING THE CLUMPY STRUCTURES WITHIN SUBMILLIMETER GALAXIES USING LASER-GUIDE STAR ADAPTIVE OPTICS SPECTROSCOPY

    SciTech Connect

    Menendez-Delmestre, Karin; Goncalves, Thiago S. [Observatorio do Valongo, Universidade Federal do Rio de Janeiro, Ladeira do Pedro Antonio 43, Saude, Rio de Janeiro, RJ 20080-090 (Brazil); Blain, Andrew W. [California Institute of Technology, MC 105-24, Pasadena, CA 91125 (United States); Swinbank, Mark; Smail, Ian [Institute for Computational Cosmology, Durham University, Durham DH1 3LE (United Kingdom); Ivison, Rob J. [UK Astronomy Technology Centre, Blackford Hill, Edinburgh EH9 3HJ (United Kingdom); Chapman, Scott C., E-mail: kmd@astro.ufrj.br [Institute of Astronomy, Madingley Road, Cambridge CB3 0HA (United Kingdom)

    2013-04-20

    We present the first integral-field spectroscopic observations of high-redshift submillimeter-selected galaxies (SMGs) using Laser-Guide Star Adaptive Optics. We target H{alpha} emission of three SMGs at redshifts z {approx} 1.4-2.4 with the OH-Suppressing Infrared Imaging Spectrograph on Keck. The spatially resolved spectroscopy of these galaxies reveals unresolved broad-H{alpha} line regions (FWHM >1000 km s{sup -1}) likely associated with an active galactic nucleus (AGN) and regions of diffuse star formation traced by narrow-line H{alpha} emission (FWHM {approx}< 500 km s{sup -1}) dominated by multiple H{alpha}-bright stellar clumps, each contributing 1%-30% of the total clump-integrated H{alpha} emission. We find that these SMGs host high star formation rate surface densities, similar to local extreme sources, such as circumnuclear starbursts and luminous infrared galaxies. However, in contrast to these local environments, SMGs appear to be undergoing such intense activity on significantly larger spatial scales as revealed by extended H{alpha} emission over 4-16 kpc. H{alpha} kinematics show no evidence of ordered global motion as would be found in a disk, but rather large velocity offsets ({approx}few Multiplication-Sign 100 km s{sup -1}) between the distinct stellar clumps. Together with the asymmetric distribution of the stellar clumps around the AGN in these objects, it is unlikely that we are unveiling a clumpy disk structure as has been suggested in other high-redshift populations of star-forming galaxies. The SMG clumps in this sample may correspond to remnants of originally independent gas-rich systems that are in the process of merging, hence triggering the ultraluminous SMG phase.

  17. NEAR-INFRARED REVERBERATION BY DUSTY CLUMPY TORI IN ACTIVE GALACTIC NUCLEI

    SciTech Connect

    Kawaguchi, Toshihiro; Mori, Masao, E-mail: kawaguti@ccs.tsukuba.ac.jp [Center for Computational Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8577 (Japan)

    2011-08-20

    According to recent models, the accretion disk and black hole in active galactic nuclei (AGNs) are surrounded by a clumpy torus. We investigate the NIR flux variation of the torus in response to a UV flash for various geometries. Anisotropic illumination by the disk and the torus self-occultation contrast our study with earlier works. Both the waning effect of each clump and the torus self-occultation selectively reduce the emission from the region with a short delay. Therefore, the NIR delay depends on the viewing angle (where a more inclined angle leads to a longer delay), and the time response shows an asymmetric profile with negative skewness, opposing the results for optically thin tori. The range of the computed delay coincides with the observed one, suggesting that the viewing angle is primarily responsible for the scatter of the observed delay. We also propose that the red NIR-to-optical color of type 1.8/1.9 objects is caused not only by the dust extinction but also the intrinsically red color. Compared with the modest torus thickness, both a thick and a thin tori display weaker NIR emission. A selection bias is thus expected such that NIR-selected AGNs tend to possess moderately thick tori. A thicker torus shows a narrower and more heavily skewed time profile, while a thin torus produces a rapid response. A super-Eddington accretion rate leads to much weaker NIR emission due to the disk self-occultation and the disk truncation by self-gravity. A long delay is expected from an optically thin and/or a largely misaligned torus. Very weak NIR emission, such as in hot-dust-poor active nuclei, can arise from a geometrically thin torus, a super-Eddington accretion rate, or a slightly misaligned torus.

  18. EVIDENCE FOR A CLUMPY, ROTATING GAS DISK IN A SUBMILLIMETER GALAXY AT z = 4

    SciTech Connect

    Hodge, J. A.; Walter, F. [Max-Planck Institute for Astronomy, Koenigstuhl 17, D-69117 Heidelberg (Germany); Carilli, C. L. [National Radio Astronomy Observatory, P.O. Box O, Socorro, NM 87801-0387 (United States); De Blok, W. J. G. [ASTRON, P.O. Box 2, 7990 AA Dwingeloo (Netherlands); Riechers, D. [Department of Astronomy, California Institute of Technology, MC 249-17, 1200 East California Boulevard, Pasadena, CA 91125 (United States); Daddi, E. [CEA, Laboratoire AIM-CNRS-Universite Paris Diderot, Irfu/SAp, Orme des Merisiers, F-91191 Gif-sur-Yvette (France); Lentati, L., E-mail: hodge@mpia.de [Astrophysics Group, Cavendish Laboratory, JJ Thomson Avenue, Cambridge CB3 0HE (United Kingdom)

    2012-11-20

    We present Karl G. Jansky Very Large Array observations of the CO(2-1) emission in the z = 4.05 submillimeter galaxy (SMG) GN20. These high-resolution data allow us to image the molecular gas at 1.3 kpc resolution just 1.6 Gyr after the big bang. The data reveal a clumpy, extended gas reservoir, 14 {+-} 4 kpc in diameter, in unprecedented detail. A dynamical analysis shows that the data are consistent with a rotating disk of total dynamical mass 5.4 {+-} 2.4 Multiplication-Sign 10{sup 11} M {sub Sun }. We use this dynamical mass estimate to constrain the CO-to-H{sub 2} mass conversion factor ({alpha}{sub CO}), finding {alpha}{sub CO} = 1.1 {+-} 0.6 M {sub Sun }(K km s{sup -1} pc{sup 2}){sup -1}. We identify five distinct molecular gas clumps in the disk of GN20 with masses a few percent of the total gas mass, brightness temperatures of 16-31K, and surface densities of >3200-4500 Multiplication-Sign ({alpha}{sub CO}/0.8) M {sub Sun} pc{sup -2}. Virial mass estimates indicate they could be self-gravitating, and we constrain their CO-to-H{sub 2} mass conversion factor to be <0.2-0.7 M {sub Sun }(K km s{sup -1} pc{sup 2}){sup -1}. A multiwavelength comparison demonstrates that the molecular gas is concentrated in a region of the galaxy that is heavily obscured in the rest-frame UV/optical. We investigate the spatially resolved gas excitation and find that the CO(6-5)/CO(2-1) ratio is constant with radius, consistent with star formation occurring over a large portion of the disk. We discuss the implications of our results in the context of different fueling scenarios for SMGs.

  19. Broadband patterned magnetic microwave absorber

    SciTech Connect

    Li, Wei; Wu, Tianlong; Wang, Wei; Guan, Jianguo, E-mail: guanjg@whut.edu.cn [State Key Lab of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070 (China); Zhai, Pengcheng [School of Science, Wuhan University of Technology, Wuhan 430070 (China)

    2014-07-28

    It is a tough task to greatly improve the working bandwidth for the traditional flat microwave absorbers because of the restriction of available material parameters. In this work, a simple patterning method is proposed to drastically broaden the absorption bandwidth of a conventional magnetic absorber. As a demonstration, an ultra-broadband microwave absorber with more than 90% absorption in the frequency range of 4–40 GHz is designed and experimentally realized, which has a thin thickness of 3.7?mm and a light weight equivalent to a 2-mm-thick flat absorber. In such a patterned absorber, the broadband strong absorption is mainly originated from the simultaneous incorporation of multiple ?/4 resonances and edge diffraction effects. This work provides a facile route to greatly extend the microwave absorption bandwidth for the currently available absorbing materials.

  20. The Multi-layer Variable Absorbers in NGC 1365 Revealed by XMM-Newton and NuSTAR

    NASA Astrophysics Data System (ADS)

    Rivers, E.; Risaliti, G.; Walton, D. J.; Harrison, F.; Arévalo, P.; Baur, F. E.; Boggs, S. E.; Brenneman, L. W.; Brightman, M.; Christensen, F. E.; Craig, W. W.; Fürst, F.; Hailey, C. J.; Hickox, R. C.; Marinucci, A.; Reeves, J.; Stern, D.; Zhang, W. W.

    2015-05-01

    Between 2012 July and 2013 February, NuSTAR and XMM-Newton performed four long-look joint observations of the type 1.8 Seyfert, NGC 1365. We have analyzed the variable absorption seen in these observations in order to characterize the geometry of the absorbing material. Two of the observations caught NGC 1365 in an unusually low absorption state, revealing complexity in the multi-layer absorber that had previously been hidden. We find the need for three distinct zones of neutral absorption in addition to the two zones of ionized absorption and the Compton-thick torus previously seen in this source. The most prominent absorber is likely associated with broad-line region clouds with column densities of around ?1023 cm?2 and a highly clumpy nature as evidenced by an occultation event in 2013 February. We also find evidence of a patchy absorber with a variable column around ?1022 cm?2 and a line-of-sight covering fraction of 0.3–0.9, which responds directly to the intrinsic source flux, possibly due to a wind geometry. A full-covering, constant absorber with a low column density of ?1 × 1022 cm?2 is also present, though the location of this low density haze is unknown.

  1. Cold Atoms

    NASA Astrophysics Data System (ADS)

    Bellac, Michel Le

    2014-11-01

    This chapter and the following one address collective effects of quantum particles, that is, the effects which are observed when we put together a large number of identical particles, for example, electrons, helium-4 or rubidium-85 atoms. We shall see that quantum particles can be classified into two categories, bosons and fermions, whose collective behavior is radically different. Bosons have a tendency to pile up in the same quantum state, while fermions have a tendency to avoid each other. We say that bosons and fermions obey two different quantum statistics, the Bose-Einstein and the Fermi-Dirac statistics, respectively. Temperature is a collective effect, and in Section 5.1 we shall explain the concept of absolute temperature and its relation to the average kinetic energy of molecules. We shall describe in Section 5.2 how we can cool atoms down thanks to the Doppler effect, and explain how cold atoms can be used to improve the accuracy of atomic clocks by a factor of about 100. The effects of quantum statistics are prominent at low temperatures, and atom cooling will be used to obtain Bose-Einstein condensates at low enough temperatures, when the atoms are bosons.

  2. Cold fusion

    SciTech Connect

    Bush, R.T. (California State Polytechnic Univ., Physics Dept., Pomona, CA (US))

    1991-03-01

    The transmission resonance model (TRM) is combined with some electrochemistry of the cathode surface and found to provide a good fit to new data on excess heat. For the first time, a model for cold fusion not only fits calorimetric data but also predicts optimal trigger points. This suggests that the model is meaningful and that the excess heat phenomenon claimed by Fleischmann and Pons is genuine. A crucial role is suggested for the overpotential and, in particular, for the concentration overpotential, i.e., the hydrogen overvoltage. Self-similar geometry, or scale invariance, i.e., a fractal nature, is revealed by the relative excess power function. Heat bursts are predicted with a scale invariance in time, suggesting a possible link between the TRM and chaos theory. The model describes a near-surface phenomenon with an estimated excess power yield of {approximately}1 kW/cm{sup 3} Pd, as compared to 50 W/cm{sup 3} of reactor core for a good fission reactor. Transmission resonance-induced nuclear transmutation, a new type of nuclear reaction, is strongly suggested with two types emphasized: transmission resonance-induced neutron transfer reactions yielding essentially the same end result as Teller's hypothesized catalytic neutron transfer and a three-body reaction promoted by standing de Broglie waves. In this paper suggestions for the anomalous production of heat, particles, and radiation are given.

  3. Cold confusion

    SciTech Connect

    Chapline, G.

    1989-07-01

    On March 23 two chemists, Martin Fleischmann and Stanley Pons startled the world with a press conference at the University of Utah where they announced that they had achieved nuclear fusion at room temperatures. As evidence they cited the production of ''excess'' amounts of heat in an electrochemical apparatus and observation of neutron production. While the production of heat in a chemical apparatus is not in itself unusual the observation of neutrons is certainly extraordinary. As it turned out, though, careful measurements of the neutron production in electrochemical apparatus similar to that used by Fleischmann and Pons carried out at dozens of other laboratories has shown that the neutron production fails by many orders of magnitude to support the assertion by Fleischmann and Pons that their discovery represents a new and cheap source of fusion power. In particular, independent measurements of the neutron production rate suggest that the actual rate of fusion energy production probably does not exceed 1 trillionth of a watt. This paper discusses the feasibility that cold fusion is actually being achieved. 7 refs.

  4. The evidence for clumpy accretion in the Herbig Ae star HR 5999

    NASA Technical Reports Server (NTRS)

    Perez, M. R.; Grady, C. A.; The, P. S.

    1993-01-01

    Analysis of IUE high- and low-dispersion spectra of the young Herbig Ae star HR 5999 (HD 144668) covering 1978-1992 revealed dramatic changes in the Mg II h and k (2795.5, 2802.7 A) emission profiles, changes in the column density and distribution in radial velocity of accreting gas, and flux in the Ly(alpha), O I, and C IV emission lines, which are correlated with the UV excess luminosity. Variability in the spectral type inferred from the UV spectral energy distribution, ranging from A5 IV-III in high state to A7 III in the low state, was also observed. The trend of earlier inferred spectral type with decreasing wavelength and with increasing UV continuum flux has previously been noted as a signature of accretion disks in lower mass pre-main sequence stars (PMS) and in systems undergoing FU Orionis-type outbursts. Our data represent the first detection of similar phenomena in an intermediate mass (M greater than or equal to 2 solar mass) PMS star. Recent IUE spectra show gas accreting toward the star with velocities as high as plus 300 km/s, much as is seen toward beta Pic, and suggest that we also view this system through the debris disk. The absence of UV lines with the rotational broadening expected given the optical data (A7 IV, V sini=180 plus or minus 20 km/s for this system) also suggests that most of the UV light originates in the disk, even in the low continuum state. The dramatic variability in the column density of accreting gas, is consistent with clumpy accretion, such as has been observed toward beta Pic, is a hallmark of accretion onto young stars, and is not restricted to the clearing phase, since detectable amounts of accretion are present for stars with 0.5 Myr less than t(sub age) less than 2.8 Myr. The implications for models of beta Pic and similar systems are briefly discussed.

  5. Abbe's law, 210 absorbing media

    E-print Network

    Stanford University

    Index Abbe's law, 210 absorbing media apparent lack of energy conservation, 197--198 exceptions--199 absorbing medium, 193, 194 absorption coefficient, 195 absorption estimator, 47 acceptance probability, 336 distribution function, see BTDF birefringence, 20 black body, 179 Boltzmann equation, 23 boundary distance

  6. Energy absorber for the CETA

    NASA Technical Reports Server (NTRS)

    Wesselski, Clarence J.

    1994-01-01

    The energy absorber that was developed for the CETA (Crew Equipment and Translation Aid) on Space Station Freedom is a metal on metal frictional type and has a load regulating feature that prevents excessive stroking loads from occurring while in operation. This paper highlights some of the design and operating aspects and the testing of this energy absorber.

  7. Submillimeter and far infrared line observations of M17 SW: A clumpy molecular cloud penetrated by UV radiation

    NASA Technical Reports Server (NTRS)

    Stutzki, J.; Stacey, G. J.; Genzel, R.; Harris, A. I.; Jaffe, d. T.; Lugten, J. B.

    1987-01-01

    Millimeter, submillimeter, and far infrared spectroscopic observations of the M17 SW star formation region are discussed. The results require the molecular cloud near the interface to be clumpy or filamentary. As a consequence, far ultraviolet radiation from the central OB stellar cluster can penetrate into the dense molecular cloud to a depth of several pc, thus creating bright and extended (CII) emission from the photodissociated surfaces of dense atomic and molecular clumps or sheets. The extended (CII) emission throughout the molecular cloud SW of the M17 complex has a level 20 times higher than expected from a single molecular cloud interface exposed to an ultraviolet radiation field typical of the solar neighborhood. This suggests that the molecular cloud as a whole is penetrated by ultraviolet radiation and has a clumpy or filamentary structure. The number of B stars expected to be embedded in the M17 molecular cloud probably can provide the UV radiation necessary for the extended (CII) emission. Alternatively, the UV radiation could be external, if the interstellar radiation in the vicinity of M17 is higher than in the solar neighborhood.

  8. Evolution of the Fraction of Clumpy Galaxies at 0.2 < z < 1.0 in the COSMOS Field

    NASA Astrophysics Data System (ADS)

    Murata, K. L.; Kajisawa, M.; Taniguchi, Y.; Kobayashi, M. A. R.; Shioya, Y.; Capak, P.; Ilbert, O.; Koekemoer, A. M.; Salvato, M.; Scoville, N. Z.

    2014-05-01

    Using the Hubble Space Telescope/Advanced Camera for Surveys data in the COSMOS field, we systematically searched clumpy galaxies at 0.2 < z < 1.0 and investigated the fraction of clumpy galaxies and its evolution as a function of stellar mass, star formation rate (SFR), and specific SFR (SSFR). The fraction of clumpy galaxies in star-forming galaxies with M star > 109.5 M ? decreases with time from ~0.35 at 0.8 < z < 1.0 to ~0.05 at 0.2 < z < 0.4, irrespective of the stellar mass, although the fraction tends to be slightly lower for massive galaxies with M star > 1010.5 M ? at each redshift. On the other hand, the fraction of clumpy galaxies increases with increasing both SFR and SSFR in all the redshift ranges we investigated. In particular, we found that the SSFR dependences of the fractions are similar among galaxies with different stellar masses, and the fraction at a given SSFR does not depend on the stellar mass in each redshift bin. The evolution of the fraction of clumpy galaxies from z ~ 0.9 to z ~ 0.3 seems to be explained by such SSFR dependence of the fraction and the evolution of SSFRs of star-forming galaxies. The fraction at a given SSFR also appears to decrease with time, but this can be due to the effect of the morphological k correction. We suggest that these results are understood by the gravitational fragmentation model for the formation of giant clumps in disk galaxies, where the gas mass fraction is a crucial parameter. Based on observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by AURA, Inc., under NASA contract NAS 5-26555. Also based on observations made with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under NASA contract 1407. Also based on data collected at the Subaru Telescope, which is operated by the National Astronomical Observatory of Japan; the XMM-Newton, an ESA science mission with instruments and contributions directly funded by ESA Member States and NASA; the European Southern Observatory under Large Program 175.A-0839, Chile; Kitt Peak National Observatory, Cerro Tololo Inter-American Observatory and the National Optical Astronomy Observatory, which are operated by the Association of Universities for Research in Astronomy, Inc. (AURA), under cooperative agreement with the National Science Foundation; and the Canada-France-Hawaii Telescope with MegaPrime/MegaCam operated as a joint project by the CFHT Corporation, CEA/DAPNIA, the NRC and CADC of Canada, the CNRS of France, TERAPIX, and the University of Hawaii.

  9. Leaf absorbance and photosynthesis

    NASA Technical Reports Server (NTRS)

    Schurer, Kees

    1994-01-01

    The absorption spectrum of a leaf is often thought to contain some clues to the photosynthetic action spectrum of chlorophyll. Of course, absorption of photons is needed for photosynthesis, but the reverse, photosynthesis when there is absorption, is not necessarily true. As a check on the existence of absorption limits we measured spectra for a few different leaves. Two techniques for measuring absorption have been used, viz. the separate determination of the diffuse reflectance and the diffuse transmittance with the leaf at a port of an integrating sphere and the direct determination of the non-absorbed fraction with the leaf in the sphere. In a cross-check both methods yielded the same results for the absorption spectrum. The spectrum of a Fuchsia leaf, covering the short-wave region from 350 to 2500 nm, shows a high absorption in UV, blue and red, the well known dip in the green and a steep fall-off at 700 nm. Absorption drops to virtually zero in the near infrared, with subsequent absorptions, corresponding to the water absorption bands. In more detailed spectra, taken at 5 nm intervals with a 5 nm bandwidth, differences in chlorophyll content show in the different depths of the dip around 550 nm and in a small shift of the absorption edge at 700 nm. Spectra for Geranium (Pelargonium zonale) and Hibiscus (with a higher chlorophyll content) show that the upper limit for photosynthesis can not be much above 700 nm. No evidence, however, is to be seen of a lower limit for photosynthesis and, in fact, some experiments down to 300 nm still did not show a decrease of the absorption although it is well recognized that no photosynthesis results with 300 nm wavelengths.

  10. HYPOTHERMIA Surviving the Cold

    E-print Network

    Machel, Hans

    HYPOTHERMIA Surviving the Cold www.WorkSafebc.com #12;About the WCB Preventing on-the-job injury-HELP) toll-free in British Columbia. #12;1 Introduction Working in a cold environment ­ whether it be cold weather, cold water, or an indoor freezer ­ is part of the job for many British Columbia workers. One

  11. Absorbent product to absorb fluids. [for collection of human wastes

    NASA Technical Reports Server (NTRS)

    Dawn, F. S.; Correale, J. V. (inventors)

    1982-01-01

    A multi-layer absorbent product for use in contact with the skin to absorb fluids is discussed. The product utilizes a water pervious facing layer for contacting the skin, overlayed by a first fibrous wicking layer, the wicking layer preferably being of the one-way variety in which fluid or liquid is moved away from the facing layer. The product further includes a first container section defined by inner and outer layer of a water pervious wicking material between which is disposed a first absorbent mass. A second container section defined by inner and outer layers between which is disposed a second absorbent mass and a liquid impermeable/gas permeable layer. Spacesuit applications are discussed.

  12. Liquid metal reactor absorber technology

    SciTech Connect

    Pitner, A.L.

    1990-10-01

    The selection of boron carbide as the reference liquid metal reactor absorber material is supported by results presented for irradiation performance, reactivity worth compatibility, and benign failure consequences. Scram response requirements are met easily with current control rod configurations. The trend in absorber design development is toward larger sized pins with fewer pins per bundle, providing economic savings and improved hydraulic characteristics. Very long-life absorber designs appear to be attainable with the application of vented pin and sodium-bonded concepts. 3 refs., 3 figs.

  13. Chaotic cold accretion on to black holes

    NASA Astrophysics Data System (ADS)

    Gaspari, M.; Ruszkowski, M.; Oh, S. Peng

    2013-07-01

    Bondi theory is often assumed to adequately describe the mode of accretion in astrophysical environments. However, the Bondi flow must be adiabatic, spherically symmetric, steady, unperturbed, with constant boundary conditions. Using 3D adaptive mesh refinement simulations, linking the 50 kpc to the sub-parsec (sub-pc) scales over the course of 40 Myr, we systematically relax the classic assumptions in a typical galaxy hosting a supermassive black hole. In the more realistic scenario, where the hot gas is cooling, while heated and stirred on large scales, the accretion rate is boosted up to two orders of magnitude compared with the Bondi prediction. The cause is the non-linear growth of thermal instabilities, leading to the condensation of cold clouds and filaments when tcool/tff ? 10. The clouds decouple from the hot gas, `raining' on to the centre. Subsonic turbulence of just over 100 km s-1 (M > 0.2) induces the formation of thermal instabilities, even in the absence of heating, while in the transonic regime turbulent dissipation inhibits their growth (tturb/tcool ? 1). When heating restores global thermodynamic balance, the formation of the multiphase medium is violent, and the mode of accretion is fully cold and chaotic. The recurrent collisions and tidal forces between clouds, filaments and the central clumpy torus promote angular momentum cancellation, hence boosting accretion. On sub-pc scales the clouds are channelled to the very centre via a funnel. In this study, we do not inject a fixed initial angular momentum, though vorticity is later seeded by turbulence. A good approximation to the accretion rate is the cooling rate, which can be used as subgrid model, physically reproducing the boost factor of 100 required by cosmological simulations, while accounting for the frequent fluctuations. Since our modelling is fairly general (turbulence/heating due to AGN feedback, galaxy motions, mergers, stellar evolution), chaotic cold accretion may be common in many systems, such as hot galactic haloes, groups and clusters. In this mode, the black hole can quickly react to the state of the entire host galaxy, leading to efficient self-regulated AGN feedback and the symbiotic Magorrian relation. Chaotic accretion can generate high-velocity clouds, likely leading to strong variations in the AGN luminosity, and the deflection or mass-loading of jets. During phases of overheating, the hot mode becomes the single channel of accretion, though strongly suppressed by turbulence. High-resolution data could determine the current mode of accretion: assuming quiescent feedback, the cold mode results in a quasi-flat-temperature core as opposed to the cuspy profile of the hot mode.

  14. The Multi-Layer Variable Absorbers in NGC 1365 Revealed by XMM-Newton and NuSTAR

    E-print Network

    Rivers, E; Walton, D J; Harrison, F; ArÉvalo, P; Baur, F E; Boggs, S E; Brenneman, L W; Brightman, M; Christensen, F E; Craig, W W; FÜrst, F; Hailey, C J; Hickox, R C; Marinucci, A; Reeves, J; Stern, D; Zhang, W W

    2015-01-01

    Between July 2012 and February 2013, NuSTAR and XMM-Newton performed four long-look joint obser- vations of the type 1.8 Seyfert, NGC 1365. We have analyzed the variable absorption seen in these observations in order to characterize the geometry of the absorbing material. Two of the observations caught NGC 1365 in an unusually low absorption state, revealing complexity in the multi-layer absorber which had previously been hidden. We find the need for three distinct zones of neutral absorption in addition to the two zones of ionized absorption and the Compton-thick torus previously seen in this source. The most prominent absorber is likely associated with broad line region clouds with column densities of around $\\sim\\,$10$^{23}$ cm$^{-2}$ and a highly clumpy nature as evidenced by an occultation event in February 2013. We also find evidence of a patchy absorber with a variable column around $\\sim\\,10^{22}$ cm$^{-2}$ and a line of sight covering fraction of 0.3$-$0.9 which responds directly to the intrinsic sou...

  15. Acceleration of thin flyer foils with a 1 MA pulsed power device for shock-wave experiments in clumpy foam targets

    Microsoft Academic Search

    Stephan Neff; Jessica Ford; David Martinez; Christopher Plechaty; Sandra Wright; Radu Presura

    2007-01-01

    The dynamics of shock waves in clumpy media are important for understanding many astrophysical processes, including the triggering of star formation in interstellar gas clouds by passing shock waves. This phenomena can be studied in the laboratory by launching a flyer plate into a low density foam with clumps. Low density foams offer the advantage of relative low sound speeds

  16. Chaotic cold accretion on to black holes in rotating atmospheres

    NASA Astrophysics Data System (ADS)

    Gaspari, M.; Brighenti, F.; Temi, P.

    2015-07-01

    The fueling of black holes is one key problem in the evolution of baryons in the universe. Chaotic cold accretion (CCA) profoundly differs from classic accretion models, as Bondi and thin disc theories. Using 3D high-resolution hydrodynamic simulations, we now probe the impact of rotation on the hot and cold accretion flow in a typical massive galaxy. In the hot mode, with or without turbulence, the pressure-dominated flow forms a geometrically thick rotational barrier, suppressing the black hole accretion rate to ~1/3 of the spherical case value. When radiative cooling is dominant, the gas loses pressure support and quickly circularizes in a cold thin disk; the accretion rate is decoupled from the cooling rate, although it is higher than that of the hot mode. In the more common state of a turbulent and heated atmosphere, CCA drives the dynamics if the gas velocity dispersion exceeds the rotational velocity, i.e., turbulent Taylor number Tat< 1. Extended multiphase filaments condense out of the hot phase via thermal instability (TI) and rain toward the black hole, boosting the accretion rate up to 100 times the Bondi rate (?• ~ ?cool). Initially, turbulence broadens the angular momentum distribution of the hot gas, allowing the cold phase to condense with prograde or retrograde motion. Subsequent chaotic collisions between the cold filaments, clouds, and a clumpy variable torus promote the cancellation of angular momentum, leading to high accretion rates. As turbulence weakens (Tat > 1), the broadening of the distribution and the efficiency of collisions diminish, damping the accretion rate ? Tat-1, until the cold disk drives the dynamics. This is exacerbated by the increased difficulty to grow TI in a rotating halo. The simulated sub-Eddington accretion rates cover the range inferred from AGN cavity observations. CCA predicts inner flat X-ray temperature and r-1 density profiles, as recently discovered in M 87 and NGC 3115. The synthetic H? images reproduce the main features of cold gas observations in massive ellipticals, as the line fluxes and the filaments versus disk morphology. Such dichotomy is key for the long-term AGN feedback cycle. As gas cools, filamentary CCA develops and boosts AGN heating; the cold mode is thus reduced and the rotating disk remains the sole cold structure. Its consumption leaves the atmosphere in hot mode with suppressed accretion and feedback, reloading the cycle.

  17. Packed Alumina Absorbs Hypergolic Vapors

    NASA Technical Reports Server (NTRS)

    Thomas, J. J.; Mauro, D. M.

    1984-01-01

    Beds of activated alumina effective as filters to remove hypergolic vapors from gas streams. Beds absorb such substances as nitrogen oxides and hydrazines and may also absorb acetylene, ethylene, hydrogen sulfide, benzene, butadiene, butene, styrene, toluene, and xoylene. Bed has no moving parts such as pumps, blowers and mixers. Reliable and energy-conservative. Bed readily adapted to any size from small portable units for use where little vapor release is expected to large stationary units for extensive transfer operations.

  18. Countercurrent flow absorber and desorber

    DOEpatents

    Wilkinson, W.H.

    1984-10-16

    Countercurrent flow absorber and desorber devices are provided for use in absorption cycle refrigeration systems and thermal boosting systems. The devices have increased residence time and surface area resulting in improved heat and mass transfer characteristics. The apparatuses may be incorporated into open cycle thermal boosting systems in which steam serves both as the refrigerant vapor which is supplied to the absorber section and as the supply of heat to drive the desorber section of the system. 9 figs.

  19. Countercurrent flow absorber and desorber

    DOEpatents

    Wilkinson, William H. (Columbus, OH)

    1984-01-01

    Countercurrent flow absorber and desorber devices are provided for use in absorption cycle refrigeration systems and thermal boosting systems. The devices have increased residence time and surface area resulting in improved heat and mass transfer characteristics. The apparatuses may be incorporated into open cycle thermal boosting systems in which steam serves both as the refrigerant vapor which is supplied to the absorber section and as the supply of heat to drive the desorber section of the system.

  20. Cold Stress and the Cold Pressor Test

    ERIC Educational Resources Information Center

    Silverthorn, Dee U.; Michael, Joel

    2013-01-01

    Temperature and other environmental stressors are known to affect blood pressure and heart rate. In this activity, students perform the cold pressor test, demonstrating increased blood pressure during a 1- to 2-min immersion of one hand in ice water. The cold pressor test is used clinically to evaluate autonomic and left ventricular function. This…

  1. Cold and Cough Medicines

    MedlinePLUS

    ... What can you do for your cold or cough symptoms? Besides drinking plenty of fluids and getting ... medicines. There are lots of different cold and cough medicines, and they do different things. Nasal decongestants - ...

  2. Mushroom plasmonic metamaterial infrared absorbers

    NASA Astrophysics Data System (ADS)

    Ogawa, Shinpei; Fujisawa, Daisuke; Hata, Hisatoshi; Uetsuki, Mitsuharu; Misaki, Koji; Kimata, Masafumi

    2015-01-01

    There has been a considerable amount of interest in the development of various types of electromagnetic wave absorbers for use in different wavelength ranges. In particular, infrared (IR) absorbers with wavelength selectivity can be applied to advanced uncooled IR sensors, which would be capable of identifying objects through their radiation spectrum. In the present study, mushroom plasmonic metamaterial absorbers (MPMAs) for the IR wavelength region were designed and fabricated. The MPMAs consist of a periodic array of thin metal micropatches connected to a thin metal plate with narrow silicon (Si) posts. A Si post height of 200 nm was achieved by isotropic XeF2 etching of a thin Si layer sandwiched between metal plates. This fabrication procedure is relatively simple and is consistent with complementary metal oxide semiconductor technology. The absorption spectra of the fabricated MPMAs were experimentally measured. In addition, theoretical calculations of their absorption properties were conducted using rigorous coupled wave analysis. Both the calculated and measured absorbance results demonstrated that these MPMAs can realize strong selective absorption at wavelengths beyond the period of the array by varying the micropatch width. Absorbance values greater than 90% were achieved. Dual- or single-mode absorption can also be selected by varying the width of the Si posts. Pixel structures using such MPMAs could be used as high responsivity, high resolution and fast uncooled IR sensors.

  3. Titanium Cold Spray Coatings

    Microsoft Academic Search

    Jihane Ajaja; Dina Goldbaum; Richard Chromik; Stephen Yue; Ahmad Rezaeian; Wilson Wong; Eric Irissou; Jean-Gabriel Legoux

    2010-01-01

    Titanium Cold Spray Coatings Cold Spray is an emerging technology used for the deposition of coatings for many industries including aerospace. This technique allows the deposition of metallic materials at low temper-atures below their melting point. The aim of this research was to develop a test technique that can measure the degree to which a cold spray coating achieves mechanical

  4. The X-Ray Warm Absorber in NGC 3516

    NASA Technical Reports Server (NTRS)

    Mathur, Smita; Wilkes, Belinda; Aldcroft, Thomas

    1997-01-01

    The Seyfert 1 galaxy, NGC 3516 has been the subject of many absorption line studies at both ultra-violet and X-ray wavelengths. In the UV, strong, broad, variable associated metal line absorption with velocity width approximately 2000 km s(exp -1) is thought to originate in gas with N(sub H)greater than or approximately 10(exp 10)cm (exp -2) lying between 0.01 and 9 pc from the central active nucleus. The Ginga X-ray data are consistent with several possibilities: a warm absorber and a cold absorber combined either with partial covering or an unusually strong reflection spectrum. We present ROSAT observations of NGC 3516 which show a strong detection of a warm absorber dominated by a blend of 0 VII/O VIII edges at approximately 0.8 keV with N(sub H) approximately 7x10(exp 21)cm(exp -2), and U:8-12. We argue that NGC 3516 contains an outflowing 'XUV' absorber showing the presence of X-ray absorption edges which are consistent with the presence of broad absorption lines in the old IUE spectra and their disappearance in the new UV observations. Our dynamical model suggests that the O VII absorption edge will continue to weaken compared to the O VIII edge, an easily testable prediction with future missions like AXAF. Eventually the source would be transparent to the X-rays unless a new absorption system is produced.

  5. Waveform-dependent absorbing metasurfaces

    E-print Network

    Wakatsuchi, Hiroki; Rushton, Jeremiah J; Sievenpiper, Daniel F

    2014-01-01

    We present the first use of a waveform-dependent absorbing metasurface for high-power pulsed surface currents. The new type of nonlinear metasurface, composed of circuit elements including diodes, is capable of storing high power pulse energy to dissipate it between pulses, while allowing propagation of small signals. Interestingly, the absorbing performance varies for high power pulses but not for high power continuous waves (CWs), since the capacitors used are fully charged up. Thus, the waveform dependence enables us to distinguish various signal types (i.e. CW or pulse) even at the same frequency, which potentially creates new kinds of microwave technologies and applications.

  6. Waveform-dependent absorbing metasurfaces.

    PubMed

    Wakatsuchi, Hiroki; Kim, Sanghoon; Rushton, Jeremiah J; Sievenpiper, Daniel F

    2013-12-13

    We present the first use of a waveform-dependent absorbing metasurface for high-power pulsed surface currents. The new type of nonlinear metasurface, composed of circuit elements including diodes, is capable of storing high-power pulse energy to dissipate it between pulses, while allowing propagation of small signals. Interestingly, the absorbing performance varies for high-power pulses but not for high-power continuous waves (CW's), since the capacitors used are fully charged up. Thus, the waveform dependence enables us to distinguish various signal types (i.e., CW or pulse) even at the same frequency, which potentially creates new kinds of microwave technologies and applications. PMID:24483674

  7. Damage tolerant light absorbing material

    DOEpatents

    Lauf, Robert J. (Oak Ridge, TN); Hamby, Jr., Clyde (Harriman, TN); Akerman, M. Alfred (Knoxville, TN); Seals, Roland D. (Oak Ridge, TN)

    1993-01-01

    A light absorbing article comprised of a composite of carbon-bonded carbon fibers, prepared by: blending carbon fibers with a carbonizable organic powder to form a mixture; dispersing the mixture into an aqueous slurry; vacuum molding the aqueous slurry to form a green article; drying and curing the green article to form a cured article; and, carbonizing the cured article at a temperature of at least about 1000.degree. C. to form a carbon-bonded carbon fiber light absorbing composite article having a bulk density less than 1 g/cm.sup.3.

  8. Damage tolerant light absorbing material

    DOEpatents

    Lauf, R.J.; Hamby, C. Jr.; Akerman, M.A.; Seals, R.D.

    1993-09-07

    A light absorbing article comprised of a composite of carbon-bonded carbon fibers, is prepared by: blending carbon fibers with a carbonizable organic powder to form a mixture; dispersing the mixture into an aqueous slurry; vacuum molding the aqueous slurry to form a green article; drying and curing the green article to form a cured article; and, carbonizing the cured article at a temperature of at least about 1000 C to form a carbon-bonded carbon fiber light absorbing composite article having a bulk density less than 1 g/cm[sup 3]. 9 figures.

  9. Waveform-Dependent Absorbing Metasurfaces

    NASA Astrophysics Data System (ADS)

    Wakatsuchi, Hiroki; Kim, Sanghoon; Rushton, Jeremiah J.; Sievenpiper, Daniel F.

    2013-12-01

    We present the first use of a waveform-dependent absorbing metasurface for high-power pulsed surface currents. The new type of nonlinear metasurface, composed of circuit elements including diodes, is capable of storing high-power pulse energy to dissipate it between pulses, while allowing propagation of small signals. Interestingly, the absorbing performance varies for high-power pulses but not for high-power continuous waves (CW’s), since the capacitors used are fully charged up. Thus, the waveform dependence enables us to distinguish various signal types (i.e., CW or pulse) even at the same frequency, which potentially creates new kinds of microwave technologies and applications.

  10. Aircraft absorbers - Promise and practice

    Microsoft Academic Search

    A. O. Andersson

    1981-01-01

    Attention is given to the application of sound absorbers to aircraft engine ducts. Fan duct application is discussed with reference to the frequency spectrum of fan noise, the wave number spectrum of fan noise, and both local and extended reactions to lining types. The design of duct linings is examined, noting a number of analysis techniques for non-uniform ducts and

  11. Oil and fat absorbing polymers

    NASA Technical Reports Server (NTRS)

    Marsh, H. E., Jr. (inventor)

    1977-01-01

    A method is described for forming a solid network polymer having a minimal amount of crosslinking for use in absorbing fats and oils. The polymer remains solid at a swelling ratio in oil or fat of at least ten and provides an oil absorption greater than 900 weight percent.

  12. Anatomy of the AGN in NGC 5548: Evidence for an unexpected, new, heavy, variable and complex absorber

    NASA Astrophysics Data System (ADS)

    Cappi, M.; De Marco, B.; Ponti, G.; NGC 5548 Collaboration

    2014-07-01

    After a very successful multi-satellite campaign on Mrk 509 in 2009, we conducted a similar campaign on the AGN NGC 5548 in 2013. The source appeared strongly absorbed in the soft X-rays during this campaign, and signatures of strong outflows were also present in the UV. A talk (PI: J. Kaastra) of an overview of this campaign is also proposed to this conference. I propose here to present the EPIC results from the campaign focusing on the analysis of the new, heavy, and variable absorber found in this otherwise archetypical type-1 source. I will put these results into context by reviewing other recent evidence for massive (either highly ionized or neutral) absorbers along the line of sight of other type-1 AGNs, and will present some of their possible interpretations under discussion in the literature: from eclipsing broad line region clouds, to clumpy dusty tori and accretion disc winds. Finally, I will argue that the combination of our new X-ray and UV data for NGC5548 places interesting and severe constraints on some of these interpretations.

  13. Gravitational Quenching by Clumpy Accretion in Galaxies and Clusters II: Dynamical Response to Heating

    E-print Network

    Birnboim, Yuval

    2010-01-01

    Galaxy clusters pose a "cooling-flow problem", where the X-ray emission from their cores is not accompanied by enough cold gas or star formation. This requires a continuous energy source that balances the cooling rate over the whole core volume. We address the feasibility of a gravitational heating mechanism, utilizing the gravitational energy released by the gas that streams into the potential well of the cluster dark-matter halo. We focus here on a specific form of gravitational heating in which the energy is transferred to the medium thorough the drag exerted on inflowing gas clumps. Using spheri-symmetric hydro simulations with a subgrid representation of these clumps, we confirm our earlier estimates that in haloes >=10^13 solar masses the gravitational heating is more efficient than the cooling everywhere. The worry was that this could overheat the core and create an instability that might push it away from equilibrium. However, we find that the overheating does not change the global halo properties, an...

  14. Full calculation of clumpiness boost factors for antimatter cosmic rays in the light of Lambda-CDM N-body simulation results

    Microsoft Academic Search

    J. Lavalle; Q. Yuan; D. Maurin; X.-J. Bi

    2007-01-01

    Anti-proton and positron Galactic cosmic ray spectra are among the key\\u000atargets for indirect detection of dark matter. The boost factors, corresponding\\u000ato an enhancement of the signal and linked to the clumpiness properties of the\\u000adark matter distribution, have been taken as high as thousands in the past. The\\u000adramatic impact of these boost factors for indirect detection of

  15. Cold fusion, Alchemist's dream

    SciTech Connect

    Clayton, E.D.

    1989-09-01

    In this report the following topics relating to cold fusion are discussed: muon catalysed cold fusion; piezonuclear fusion; sundry explanations pertaining to cold fusion; cosmic ray muon catalysed cold fusion; vibrational mechanisms in excited states of D{sub 2} molecules; barrier penetration probabilities within the hydrogenated metal lattice/piezonuclear fusion; branching ratios of D{sub 2} fusion at low energies; fusion of deuterons into {sup 4}He; secondary D+T fusion within the hydrogenated metal lattice; {sup 3}He to {sup 4}He ratio within the metal lattice; shock induced fusion; and anomalously high isotopic ratios of {sup 3}He/{sup 4}He.

  16. On the Connection Between Metal Absorbers and Quasar Nebulae

    E-print Network

    Doron Chelouche; Brice Ménard; David V. Bowen; Orly Gnat

    2007-06-28

    We establish a simple model for the distribution of cold gas around L* galaxies using a large set of observational constraints on the properties of strong MgII absorber systems. Our analysis suggests that the halos of L* galaxies are filled with cool gaseous clouds having sizes of order 1kpc and densities of ~10^{-2} cm^{-3}. We then investigate the physical effects of cloud irradiation by a quasar and study the resulting spectral signatures. We show that quasar activity gives rise to (i) extended narrow-line emission on ~100kpc scales and (ii) an anisotropy in the properties of the absorbing gas arising from the geometry of the quasar radiation field. Provided that quasars reside in halos several times more massive than those of L* galaxies, our model predictions appear to be in agreement with observations of narrow emission-line nebulae around quasars and the recent detections of ~100kpc cold gaseous envelopes around those objects, suggesting a common origin for these phenomena. We discuss the implications of our results for understanding absorption systems, probing quasar environments at high redshifts, and testing the quasar unification scheme.

  17. Are strong MgII Absorbers Signatures of Outflows?

    NASA Astrophysics Data System (ADS)

    Bouché, N.; Murphy, M. T.; Péroux, C.

    2012-09-01

    Low-ionization transitions such as the Mg ii?2796/2803 doublet trace cold gas in the vicinity of galaxies. The exact physical origin of this cold gas traced by QSO absorption lines is debated. Does it trace gas in disks, halos, merger tails, and even in outflows? Recent studies of strong starbursts and post-starbursts at intermediate redshifts have shown that Mg ii are seen in outflows, with blue-shifted velocities ˜500 - 1500km s-1. Strong intervening Mg ii absorbers (with equivalent width Wr?2796 > 1Å) may be tracing the denser and colder gas of starburst-driven outflows. Indeed, based on Mg ii statistics, our clustering analysis has shown that the host-galaxy mass is anti-correlated with the line-of-sight velocity ?v (as measured from Wr?2796). If Mg ii absorbers were virialized in galaxy halos, a positive Mh-Wr correlation would have been observed. Our result thus shows that the Mg ii clouds are not virialized in the gaseous halos of the host-galaxies.

  18. Absorbable biologically based internal fixation.

    PubMed

    Ibrahim, Ahmed M S; Koolen, Pieter G L; Kim, Kuylhee; Perrone, Gabe S; Kaplan, David L; Lin, Samuel J

    2015-01-01

    Absorbable devices for use in internal fixation have advanced over the years to become reliable and cost-effective alternatives to metallic hardware. In the past, biodegradable fixation involved a laborious implantation process, and induced osteolysis and inflammatory reactions. Modern iterations exhibit increased strength, smoother resorption, and lower rates of reactivity. A newer generation manufactured from silk has emerged that may address existing limitations and provide a greater range of fixation applications. PMID:25440418

  19. THE THICK DISKS OF SPIRAL GALAXIES AS RELICS FROM GAS-RICH, TURBULENT, CLUMPY DISKS AT HIGH REDSHIFT

    SciTech Connect

    Bournaud, Frederic; Martig, Marie [CEA, IRFU, SAp, 91191 Gif-sur-Yvette (France); Elmegreen, Bruce G. [IBM Research Division, T.J. Watson Research Center, P.O. Box 218, Yorktown Heights, NY 10598 (United States)

    2009-12-10

    The formation of thick stellar disks in spiral galaxies is studied. Simulations of gas-rich young galaxies show formation of internal clumps by gravitational instabilities, clump coalescence into a bulge, and disk thickening by strong stellar scattering. The bulge and thick disks of modern galaxies may form this way. Simulations of minor mergers make thick disks too, but there is an important difference. Thick disks made by internal processes have a constant scale height with galactocentric radius, but thick disks made by mergers flare. The difference arises because in the first case, perpendicular forcing and disk-gravity resistance are both proportional to the disk column density, so the resulting scale height is independent of this density. In the case of mergers, perpendicular forcing is independent of the column density and the low-density regions get thicker; the resulting flaring is inconsistent with observations. Late-stage gas accretion and thin-disk growth are shown to preserve the constant scale heights of thick disks formed by internal evolution. These results reinforce the idea that disk galaxies accrete most of their mass smoothly and acquire their structure by internal processes, in particular through turbulent and clumpy phases at high redshift.

  20. Is It a Cold or the Flu? Symptoms Cold Flu

    E-print Network

    Bandettini, Peter A.

    Is It a Cold or the Flu? Symptoms Cold Flu Fever Rare Usual; high (100°F to 102°F, occasionally with a cold Annual vaccination; antiviral medicines--see your doctor Complications Sinus congestion Middle ear

  1. Cold-adapted archaea

    Microsoft Academic Search

    Ricardo Cavicchioli

    2006-01-01

    Many archaea are extremophiles. They thrive at high temperatures, at high pressure and in concentrated acidic environments. Nevertheless, the largest proportion and greatest diversity of archaea exist in cold environments. Most of the Earth's biosphere is cold, and archaea represent a significant fraction of the biomass. Although psychrophilic archaea have long been the neglected majority, the study of these microorganisms

  2. Ultra-Cold Molecules

    Microsoft Academic Search

    A. Fioretti; M. Fazzi; M. Mazzoni; T. Ban; C. Gabbanini

    2004-01-01

    In this paper we overview recent results on the formation of translationally cold molecules. While there are some methods relying on direct cooling of molecules, we shall concentrate on the photoassociation technique that starts from laser-cooled atoms. The detection methods for the ultra-cold molecules will be presented together with a report on the trapping techniques. The treatment is mainly focused

  3. Cold Air Damming

    NSDL National Science Digital Library

    2014-09-14

    Cold Air Damming is part of the Mesoscale Meteorology Primer series. This module first presents a Navy forecast scenario prior to the development of a major cold air damming (CAD) event along the east slopes of the Appalachian Mountains. Then, from a conceptual standpoint, the classic CAD scenario is described in detail, both from an observational and modeling standpoint.

  4. Mulitlayered Nanostructured Broad Band Absorber

    NASA Astrophysics Data System (ADS)

    Corrigan, Timothy; Ide, Benjamin

    2013-03-01

    Wasted energy in the form of heat is perhaps the largest source of lost energy making many power systems inefficient. Systems designed to convert heat into useful energy need a method of collecting the heat. We previously described a multilayer design with successive thin metallic and dielectric (non-metal and transparent) layers, where each successive metallic layer absorbs a small fraction of the radiation. However, the regular thickness of the dielectric layer causes reflection peaks, or regions where no absorption occurs. In this work we describe a similar design where we eliminated the undesirable reflection peaks using varying thicknesses of the dielectric layer.

  5. Porcelain enamel neutron absorbing material

    DOEpatents

    Iverson, D.C.

    1987-11-20

    A porcelain enamel composition as a neutron absorbing material can be prepared of a major proportion by weight of a cadmium compound and a minor proportion of compound of boron, lithium and silicon. These compounds in the form of a porcelain enamel coating or layer on several alloys has been found to be particularly effective in enhancing the nuclear safety of equipment for use in the processing and storage of fissile material. The composition of the porcelain enamel coating can be tailored to match the coefficient of thermal expansion of the equipment to be coated and excellent coating adhesion can be achieved. 2 figs.

  6. 21 CFR 886.3300 - Absorbable implant (scleral buckling method).

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...false Absorbable implant (scleral buckling method). 886.3300 Section...3300 Absorbable implant (scleral buckling method). (a) Identification. An absorbable implant (scleral buckling method) is a device intended...

  7. 21 CFR 886.3300 - Absorbable implant (scleral buckling method).

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...false Absorbable implant (scleral buckling method). 886.3300 Section...3300 Absorbable implant (scleral buckling method). (a) Identification. An absorbable implant (scleral buckling method) is a device intended...

  8. 21 CFR 886.3300 - Absorbable implant (scleral buckling method).

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...false Absorbable implant (scleral buckling method). 886.3300 Section...3300 Absorbable implant (scleral buckling method). (a) Identification. An absorbable implant (scleral buckling method) is a device intended...

  9. 21 CFR 886.3300 - Absorbable implant (scleral buckling method).

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...false Absorbable implant (scleral buckling method). 886.3300 Section...3300 Absorbable implant (scleral buckling method). (a) Identification. An absorbable implant (scleral buckling method) is a device intended...

  10. Prescription Drugs and Cold Medicines

    MedlinePLUS

    ... Drugs of Abuse » Prescription Drugs & Cold Medicines Prescription Drugs & Cold Medicines Email Facebook Twitter What is Prescription Drug Abuse: Some medications have psychoactive (mind-altering) properties ...

  11. The young low-mass star ISO-Oph-50: extreme variability induced by a clumpy, evolving circumstellar disc

    NASA Astrophysics Data System (ADS)

    Scholz, Alexander; Muži?, Koraljka; Geers, Vincent

    2015-07-01

    ISO-Oph-50 is a young low-mass object in the ˜1 Myr old Ophiuchus star-forming region undergoing dramatic changes in its optical/near/mid-infrared brightness by 2-4 mag. We present new multi-band photometry and near-infrared spectra, combined with a synopsis of the existing literature data. Based on the spectroscopy, the source is confirmed as a mid-M dwarf, with evidence for ongoing accretion. The near-infrared light curves show large-scale variations, with 2-4 mag amplitude in the bands IJHK, with the object generally being bluer when faint. Near its brightest state, the object shows colour changes consistent with variable extinction of ?AV ˜ 7 mag. High-cadence monitoring at 3.6 ?m reveals quasi-periodic variations with a typical time-scale of 1-2 weeks. The best explanation for these characteristics is a low-mass star seen through circumstellar matter, whose complex variability is caused by changing inhomogeneities in the inner parts of the disc. When faint, the direct stellar emission is blocked; the near-infrared radiation is dominated by scattered light. When bright, the emission is consistent with a photosphere strongly reddened by circumstellar dust. Based on the available constraints, the inhomogeneities have to be located at or beyond ˜0.1 au distance from the star. If this scenario turns out to be correct, a major portion of the inner disc has to be clumpy, structured, and/or in turmoil. In its observational characteristics, this object resembles other types of young stellar objects with variability caused in the inner disc. Compared to other objects, however, ISO-Oph-50 is clearly an extreme case, given the large amplitude of the brightness and colour changes combined with the erratic behaviour. ISO-Oph-50 has been near its brightest state since 2013; further monitoring is highly encouraged.

  12. Warm absorbers in X-rays (WAX), a comprehensive high resolution grating spectral study of a sample of Seyfert galaxies: I. A global view and frequency of occurrence of warm absorbers

    E-print Network

    Laha, Sibasish; Dewangan, Gulab C; Chakravorty, Susmita; Kembhavi, Ajit K

    2014-01-01

    We present results from a homogeneous analysis of the broadband 0.3-10 keV CCD resolution as well as of soft X-ray high-resolution grating spectra of a hard X-ray flux-limited sample of 26 Seyfert galaxies observed with XMM-Newton. Our goal is to characterise the warm absorber (WA) properties along the line-of-sight to the active nucleus. We significantly detect WAs in $65\\%$ of the sample sources. Our results are consistent with WAs being present in at least half of the Seyfert galaxies in the nearby Universe, in agreement with previous estimates . We find a gap in the distribution of the ionisation parameter in the range $0.5warm absorber flow is probably constituted by a clumpy distribution of discrete clouds rather than a continuous medium. The distribution of the WA column densities for the sources with broad Fe K$\\alpha$ lines are similar to those sources which do not have broadened emission l...

  13. Cold Sores (HSV-1)

    MedlinePLUS

    ... anywhere on the body, including the genital area. Genital herpes isn't typically caused by HSV-1; it's ... Parents MORE ON THIS TOPIC Can You Get Genital Herpes From a Cold Sore? Mononucleosis Genital Herpes Tips ...

  14. Colds and the Flu

    MedlinePLUS

    ... with green- or yellow-colored discharge) Sore throat Cough Sneezing Fatigue Muscle aches Headache Watery eyes Cold ... aches, especially in your back, arms and legs Cough Headache Loss of appetite What is H1N1 flu? ...

  15. Cold hardiness in molluscs

    NASA Astrophysics Data System (ADS)

    Ansart, Armelle; Vernon, Philippe

    2003-05-01

    Molluscs inhabit all types of environments: seawater, intertidal zone, freshwater and land, and of course may have to deal with subzero temperatures. Ectotherm animals survive cold conditions by avoiding it by extensive supercooling (freezing avoidant species) or by bearing the freezing of their extracellular body fluids (freezing tolerant species). Although some studies on cold hardiness are available for intertidal molluscs, they are scarce for freshwater and terrestrial ones. Molluscs often exhibit intermediary levels of cold hardiness, with a moderate or low ability to supercool and a limited survival to the freezing of their tissues. Several factors could be involved: their dependence on water, their ability to enter dormancy, the probability of inoculative freezing in their environment, etc. Size is an important parameter in the development of cold hardiness abilities: it influences supercooling ability in land snails, which are rather freezing avoidant and survival to ice formation in intertidal organisms, which generally tolerate freezing.

  16. Transmission of colds

    Microsoft Academic Search

    Diane E. Pappas; J. Owen Hendley

    Rhinorrhea, nasal congestion, and sore throat herald the beginning of the cold season for both children and adults. Although\\u000a the common cold is a self-limited infection, there are no effective treatments presently available and complications, missed\\u000a time from work and school, and overall discomfort are not insignificant. Understanding how infections are transmitted may\\u000a lead to interventions to reduce rates of

  17. Neutron Mössbauer effect and the cold fusion in inhomogeneous materials

    Microsoft Academic Search

    H. Kozima

    1994-01-01

    Summary  In relation with the trapped-neutron catalized model (TNCF model) to explain the Cold Fusion phenomenon, the neutron Mössbauer\\u000a effect is proposed to trap neutrons in a crystal composed of nuclei which can absorb a neutron resonantly to form an excited\\u000a state of an isotope. This mechanism of neutron trapping depends on the distribution of the protons (and\\/or deuterons) in the

  18. Oxalate: Effect on calcium absorbability

    SciTech Connect

    Heaney, R.P.; Weaver, C.M. (Creighton Univ., Omaha, NE (USA))

    1989-10-01

    Absorption of calcium from intrinsically labeled Ca oxalate was measured in 18 normal women and compared with absorption of Ca from milk in these same subjects, both when the test substances were ingested in separate meals and when ingested together. Fractional Ca absorption from oxalate averaged 0.100 +/- 0.043 when ingested alone and 0.140 +/- 0.063 when ingested together with milk. Absorption was, as expected, substantially lower than absorption from milk (0.358 +/- 0.113). Nevertheless Ca oxalate absorbability in these women was higher than we had previously found for spinach Ca. When milk and Ca oxalate were ingested together, there was no interference of oxalate in milk Ca absorption and no evidence of tracer exchange between the two labeled Ca species.

  19. Electromagnetic scattering by pyramidal and wedge absorber

    NASA Technical Reports Server (NTRS)

    Dewitt, Brian T.; Burnside, Walter D.

    1988-01-01

    Electromagnetic scattering from pyramidal and wedge absorbers used to line the walls of modern anechoic chambers is measured and compared with theoretically predicted values. The theoretical performance for various angles of incidence is studied. It is shown that a pyramidal absorber scatters electromagnetic energy more as a random rough surface does. The apparent reflection coefficient from an absorber wall illuminated by a plane wave can be much less than the normal absorber specifications quoted by the manufacturer. For angles near grazing incidence, pyramidal absorbers give a large backscattered field from the pyramid side-faces or edges. The wedge absorber was found to give small backscattered fields for near-grazing incidence. Based on this study, some new guidelines for the design of anechoic chambers are advocated because the specular scattering models used at present do not appear valid for pyramids that are large compared to the wavelength.

  20. Absorbable staples in continent ileal urinary pouch.

    PubMed

    Bonney, W W; Robinson, R A

    1990-01-01

    Continent ileal urinary reservoirs were created in dogs to study absorbable surgical staples. Within each pouch, certain controlled observations were possible. The staples and chemically similar polyglactin absorbable sutures caused almost identical tissue reactions. The staples outlasted the sutures, probably because of greater size. Inverted and everted staple closures worked equally well. It appears feasible to consider clinical urinary diversion with absorbable staples, a time-saving method. PMID:2404367

  1. Absorbent product and articles made therefrom

    NASA Technical Reports Server (NTRS)

    Dawn, F. S.; Correale, J. V. (inventors)

    1982-01-01

    A multilayer absorbent product for use in contact with the skin to absorb fluids is described. The product has a water pervious facing layer for contacting the skin, and a first fibrous wicking layer overlaying the water pervious layer. A first container section is defined by inner and outer layers of a water pervious wicking material in between a first absorbent mass and a second container section defined by inner and outer layers of a water pervious wicking material between what is disposed a second absorbent mass, and a liquid impermeable/gas permeable layer overlaying the second fibrous wicking layer.

  2. Advanced Reflector and Absorber Materials (Fact Sheet)

    SciTech Connect

    Not Available

    2010-08-01

    Fact sheet describing NREL CSP Program capabilities in the area of advanced reflector and absorber materials: evaluating performance, determining degradation rates and lifetime, and developing new coatings.

  3. Boron-copper neutron absorbing material and method of preparation

    DOEpatents

    Wiencek, Thomas C. (Bolingbrook, IL); Domagala, Robert F. (Indian Head Park, IL); Thresh, Henry (Palos Hts., IL)

    1991-01-01

    A composite, copper clad neutron absorbing material is comprised of copper powder and boron powder enriched with boron 10. The boron 10 content can reach over 30 percent by volume, permitting a very high level of neutron absorption. The copper clad product is also capable of being reduced to a thickness of 0.05 to 0.06 inches and curved to a radius of 2 to 3 inches, and can resist temperatures of 900.degree. C. A method of preparing the material includes the steps of compacting a boron-copper powder mixture and placing it in a copper cladding, restraining the clad assembly in a steel frame while it is hot rolled at 900.degree. C. with cross rolling, and removing the steel frame and further rolling the clad assembly at 650.degree. C. An additional sheet of copper can be soldered onto the clad assembly so that the finished sheet can be cold formed into curved shapes.

  4. Antioxidant properties of cold-pressed black caraway, carrot, cranberry, and hemp seed oils

    Microsoft Academic Search

    Liangli Lucy Yu; Kequan Kevin Zhou; John Parry

    2005-01-01

    Cold-pressed black caraway, carrot, cranberry, and hemp seed oils were extracted with methanol and evaluated for radical-scavenging activities against ABTS+ and DPPH, chelating activity, oxygen radical absorbing capacity (ORAC), and total phenolic contents (TPC). All the oil extracts had significant antioxidant activities. The ORAC value ranged from 28 to 220 ?mol TE\\/g oil for the cold-pressed hemp, carrot, and black

  5. Clumpy stellar winds and high-energy emission in high-mass binaries hosting a young pulsar

    NASA Astrophysics Data System (ADS)

    Bosch-Ramon, V.

    2013-12-01

    Context. High-mass binaries hosting young pulsars can be powerful gamma-ray emitters. The stellar wind of the massive star in the system, which interacts with the pulsar wind, is expected to be clumpy. Since the high-energy emission comes from the interaction of the two winds, the presence of clumps can affect the spectrum and variability of this radiation. Aims: We look for the main effects of the presence of clumps in the stellar wind in the two-wind interaction region and in the non-thermal radiation that originates there. Methods: A simple analytical model for the two-wind interaction dynamics was developed. The model accounts for the lifetime of clumps under the pulsar-wind impact. This time plays a very important role with regard to the evolution of the clump, the magnetic field in the clump-pulsar wind interaction region, and the non-radiative and radiative cooling of the non-thermal particles. We also computed the high-energy emission produced at the interaction of long-living clumps with the pulsar wind. Results: For reasonable parameters, the clumps will induce small variability on the X-ray and gamma-ray radiation. Sporadically, large clumps can reach closer to the pulsar increasing the magnetic field, triggering synchrotron X-ray flares and weakening other emission components like inverse Compton. The reduction of the emitter size induced by clumps also makes non-radiative losses faster. Stellar wind clumps can also enhance instability development and matter entrainment in the shocked pulsar wind when it leaves the binary. Growth limitations of the clumps from the wind acceleration region may imply that a different origin for the largest clumps is required. The large-scale wind structures behind the observed discrete absorption components in the ultraviolet may be the source of these large clumps. Conclusions: The presence of structure in the stellar wind can produce substantial energy-dependent variability and thus should not be neglected when studying the broadband emission from high-mass binaries hosting young pulsars.

  6. Detection of cold pain, cold allodynia and cold hyperalgesia in freely behaving rats

    Microsoft Academic Search

    Andrew J Allchorne; Daniel C Broom; Clifford J Woolf

    2005-01-01

    BACKGROUND: Pain is elicited by cold, and a major feature of many neuropathic pain states is that normally innocuous cool stimuli begin to produce pain (cold allodynia). To expand our understanding of cold induced pain states we have studied cold pain behaviors over a range of temperatures in several animal models of chronic pain. RESULTS: We demonstrate that a Peltier-cooled

  7. Study on utilization of cold energy from natural ice—Ice-making efficiency of small ice containers stacked in a cold room

    Microsoft Academic Search

    Masato Kimura; Shin-ichi Urano; Keiji Okada; Torahiko Saeki

    2010-01-01

    Recently, the efficient use of cold energy, a type of natural energy derived from snow and ice, has been studied as an energy-saving measure to cut emissions of carbon dioxide. For example, the Ice Shelter, which is constructed with natural ice, was developed to create an environment with low ambient temperature and high humidity using latent heat absorbed or released

  8. Mid-infrared diagnostics of starburst galaxies: clumpy, dense structures in star-forming regions in the Antennae (NGC 4038/4039)

    E-print Network

    Leonie Snijders; Lisa J. Kewley; Paul P. van der Werf

    2007-07-10

    Recently, mid-infrared instruments have become available on several large ground-based telescopes, resulting in data sets with unprecedented spatial resolution at these long wavelengths. In this paper we examine 'ground-based-only' diagnostics, which can be used in the study of star-forming regions in starburst galaxies. By combining output from the stellar population synthesis code Starburst 99 with the photoionization code Mappings, we model stellar clusters and their surrounding interstellar medium, focusing on the evolution of emission lines in the N- and Q-band atmospheric windows (8-13 and 16.5-24.5 micron respectively) and those in the near-infrared. We address the detailed sensitivity of various emission line diagnostics to stellar population age, metallicity, nebular density, and ionization parameter. Using our model results, we analyze observations of two stellar clusters in the overlap region of the Antennae galaxies obtained with VLT Imager and Spectrometer for mid Infrared (VISIR). We find evidence for clumpy, high density, ionized gas. The two clusters are young (younger than 2.5 and 3 Myr respectively), the surrounding interstellar matter is dense (10^4 cm^-3 or larger) and can be characterized by a high ionization parameter (logU > -1.53). Detailed analysis of the mid-infrared spectral features shows that a (near-)homogeneous medium cannot account for the observations, and that complex structure on scales below the resolution limit, containing several young stellar clusters embedded in clumpy gas, is more likely.

  9. Photochemistry in the inner layers of clumpy circumstellar envelopes: formation of water in C-rich objects and of C-bearing molecules in O-rich objects

    E-print Network

    Agundez, Marcelino; Guelin, Michel

    2010-01-01

    A mechanism based on the penetration of interstellar ultraviolet photons into the inner layers of clumpy circumstellar envelopes around AGB stars is proposed to explain the non-equilibrium chemistry observed in such objects. We show through a simple modelling approach that in circumstellar envelopes with a certain degree of clumpiness or with moderately low mass loss rates (a few 10^(-7) solar masses per year) a photochemistry can take place in the warm and dense inner layers inducing important changes in the chemical composition. In carbon-rich objects water vapor and ammonia would be formed with abundances of 10^(-8) - 10(^-6) relative to H2, while in oxygen-rich envelopes ammonia and carbon-bearing molecules such as HCN and CS would form with abundances of 10^(-9) - 10^(-7) relative to H2. The proposed mechanism would explain the recent observation of warm water vapor in the carbon-rich envelope IRC +10216 with the Herschel Space Observatory, and predict that H2O should be detectable in other carbon-rich o...

  10. PHOTOCHEMISTRY IN THE INNER LAYERS OF CLUMPY CIRCUMSTELLAR ENVELOPES: FORMATION OF WATER IN C-RICH OBJECTS AND OF C-BEARING MOLECULES IN O-RICH OBJECTS

    SciTech Connect

    Agundez, Marcelino [LUTH, Observatoire de Paris-Meudon, 5 Place Jules Janssen, 92190 Meudon (France); Cernicharo, Jose [Departamento de Astrofisica, Centro de AstrobiologIa, CSIC-INTA, Ctra. de Torrejon a Ajalvir km 4, Torrejon de Ardoz, 28850 Madrid (Spain); Guelin, Michel, E-mail: marcelino.agundez@obspm.f [Institut de Radioastronomie Millimetrique, 300 rue de la Piscine, 38406 Saint Martin d'Heres (France)

    2010-12-01

    A mechanism based on the penetration of interstellar ultraviolet photons into the inner layers of clumpy circumstellar envelopes (CSEs) around asymptotic giant branch stars is proposed to explain the non-equilibrium chemistry observed in such objects. We show through a simple modeling approach that in CSEs with a certain degree of clumpiness or with moderately low mass loss rates (a few 10{sup -7} M {sub sun} yr{sup -1}) a photochemistry can take place in the warm and dense inner layers, inducing important changes in the chemical composition. In carbon-rich objects water vapor and ammonia would be formed with abundances of 10{sup -8}-10{sup -6} relative to H{sub 2}, while in oxygen-rich envelopes ammonia and carbon-bearing molecules such as HCN and CS would form with abundances of 10{sup -9}-10{sup -7} relative to H{sub 2}. The proposed mechanism would explain the recent observation of warm water vapor in the carbon-rich envelope IRC+10216 with the Herschel Space Observatory and predict that H{sub 2}O should be detectable in other carbon-rich objects.

  11. Full Calculation of Clumpiness Boost factors for Antimatter Cosmic Rays in the light of \\LambdaCDM N-body simulation results

    E-print Network

    Lavalle, J; Maurin, D; Bi, X -J

    2007-01-01

    Anti-proton and positron Galactic cosmic ray (GCR) spectra are among the key targets for indirect detection of dark matter (DM). The boost factors, corresponding to an enhancement of the signal|linked to the clumpiness properties of the dark matter distribution|, have been taken as high as thousands in the past. The dramatic impact of these boost factors for indirect detection of antiparticles, for instance with the PAMELA satellite or the coming AMS-02 experiment, asks for their detailed calculation. We take into account the state-of-the-art results of high resolution N-body dark matter simulations to calculate the most likely energy dependent boost factors|linked to the GCR propagation properties|, for anti-protons and positrons. The results from extreme, but still possible, configurations of the clumpy dark matter component is also discussed. Starting from the mass and space distributions of sub-halos, the anti-proton and positron propagators are used to calculate the mean value and the variance of the boo...

  12. A uniflow absorbent oil regenerator

    SciTech Connect

    Sidogin, V.P.; Babitsin, S.M.; Brodskii, E.V.; Gulyaev, V.M.; Khomin, V.T.

    1984-01-01

    The uniflow absorbent oil regenerator presented in this article has been developed and introduced at the Dnepropetrovsk Coking Plant in conjunction with the Dnepropetrovsk Chemical and Technological Institute. The body of the device is a convergent duct with a cylindrical neck and a diffuser. A conical oil receptacle and conical inserts are positioned in the convergent duct. A connecting pipe for gas input and a connecting pipe for injecting oil into a conical receptacle are placed on the upper end shield of the body. A swirler made out of inclined vanes which partly overlap inside is placed at the diffuser outlet. A cylinder, contained in a steam jacket with chokes for letting in steam and letting out condensate, is positioned under the diffuser. The gas-removal connecting pipe, mounted on a lower end shield of the device, is partially recessed inside the cylinder, and forms with its inside walls a collector for the annular section which is supplied with a connecting pipe for removal of the liquid phase (polymers).

  13. Cold Regions Bibliography

    NSDL National Science Digital Library

    A joint endeavor of the Federal Research Division of the Library of Congress and the US Army Cold Regions Research and Engineering Laboratory (CRREL), this project disseminates information on Antarctica and cold regions science and technology "by maintaining and continually updating a database which is an accumulation of over 40 years of materials on the science and technology of the world's cold regions." This database currently contains over 208,000 records, with about 6,000 accessions annually. After entering a supplied user id and password, users can search the database by keyword, author, or year of publication. Search returns include title, source, and a link to more information, including pages, notes, series, and publisher information. A DOS version of the database is also available for limited periods to qualified researchers. More information is available at the site.

  14. Cold asymmetrical fermion superfluids

    SciTech Connect

    Caldas, Heron

    2003-12-19

    The recent experimental advances in cold atomic traps have induced a great amount of interest in fields from condensed matter to particle physics, including approaches and prospects from the theoretical point of view. In this work we investigate the general properties and the ground state of an asymmetrical dilute gas of cold fermionic atoms, formed by two particle species having different densities. We have show in a recent paper, that a mixed phase composed of normal and superfluid components is the energetically favored ground state of such a cold fermionic system. Here we extend the analysis and verify that in fact, the mixed phase is the preferred ground state of an asymmetrical superfluid in various situations. We predict that the mixed phase can serve as a way of detecting superfluidity and estimating the magnitude of the gap parameter in asymmetrical fermionic systems.

  15. Absorbance Changes of Carotenoids in Different Solvents

    Microsoft Academic Search

    Lun-Yi Zang; Olaf Sommerburg; Frederik J. G. M van Kuijk

    1997-01-01

    Carotenoids are typically measured in tissues with the high performance liquid chromatography (HPLC) and quantitation is usually done by calibrating with stock solutions in solvents. Four carotenoids including lutein, zeaxanthin, lycopene and ?-carotene were dissolved in hexane and methanol respectively, and their absorbance characteristeris were compared. Lutein shows absorbance spectra that are almost independent of solvents at various concentrations. Spectra

  16. Proton Absorber Feasibility Study Chris Rogers,

    E-print Network

    McDonald, Kirk

    Proton Absorber ­ Feasibility Study Chris Rogers, ASTeC, Rutherford Appleton Laboratory 14 Sept 2010 #12;Overview We have a problem with secondary protons in the front end Deposit significant Need remote handling (ouch) One way to fix this is using a proton absorber Change in beam power

  17. Method of fabricating a solar absorber panel

    Microsoft Academic Search

    Severson

    1982-01-01

    A low-cost method of fabricating a solar absorber panel for use with a flat plate solar collector system is disclosed in which a plurality of formed elongated substantially u-shaped members are fixed in a predetermined configuration to the reverse side of a single sheet absorber member forming therewith hollow fluid passages or ducts. The fluid duct members are provided with

  18. SYNCHROTRON RADIATION ABSORBERS FOR HADRON COLLIDERS

    Microsoft Academic Search

    P. Bauer; K. Ewald; C. Darve; P. J. Limon; T. Nicol; N. Solyak; I. Terechkine; A. Barcikowski; J. Noonan; R. Rosenberg; E. Rotela; B. Rusthoven; S. Sharma

    We present the results of a design study of synchrotron radiation absorbers, or photon stops, conducted in the context of a recent study of a Very Large Hadron Collider (VLHC), (1). Photon stops protrude into the beam tube at the end of each bending magnet to absorb the synchrotron radiation emitted by the beams. They operate at room temperature and

  19. Cold spray nozzle design

    DOEpatents

    Haynes, Jeffrey D. (Stuart, FL); Sanders, Stuart A. (Palm Beach Gardens, FL)

    2009-06-09

    A nozzle for use in a cold spray technique is described. The nozzle has a passageway for spraying a powder material, the passageway having a converging section and a diverging section, and at least the diverging section being formed from polybenzimidazole. In one embodiment of the nozzle, the converging section is also formed from polybenzimidazole.

  20. Disinfestation with Cold

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This book chapter by Neil Heather and Guy Hallman, in “Pest Management and Phytosanitary Trade Barriers,” CABI Press, reviews the history and current status of cold as a phytosanitary treatment and makes recommendations for future research. The recent problems with Mediterranean fruit fly in Clemen...

  1. Teaching "In Cold Blood."

    ERIC Educational Resources Information Center

    Berbrich, Joan D.

    1967-01-01

    The Truman Capote nonfiction novel, "In Cold Blood," which reflects for adolescents the immediacy of the real world, illuminates (1) social issues--capital punishment, environmental influence, and the gap between the "haves" and "have-nots," (2) moral issues--the complexity of man's nature, the responsibility of one man for another, and the place…

  2. Torsional vibration reduction using passive nonlinear absorbers

    NASA Astrophysics Data System (ADS)

    Shaw, Steven W.; Alsuwaiyan, Abdallah

    2000-04-01

    This paper considers the dynamic performance of systems of centrifugal pendulum vibration absorbers that are used to attenuate torsional vibrations in rotating systems. These absorbers, which can be found in certain IC engines and helicopter rotors, consist of movable masses whose centers of mass are kinematically restricted to move along prescribed paths relative to the rotor of interest. The most common choice for absorber paths are simple circles that are slightly mistuned from the desired order, so that undesirable nonlinear behaviors are avoided when the absorbers undergo large amplitude motions. In this work we consider a range of different path types and tunings, with the goal of optimizing performance over a wide operating range. This analytical study relies on a mathematical model of a rotor fitted with N identical, general-path absorbers, and utilizes perturbation techniques to obtain analytical estimates for the response of the rotor and the absorbers. The results are used to select path parameters based on selected performance measures, and the results are verified via simulation studies. It is shown that slightly overtuned cycloidal paths provide excellent vibration reduction characteristics and prevent the occurrence of nonlinear instabilities and vibration localization in the response of the absorbers.

  3. Thin film absorber for a solar collector

    DOEpatents

    Wilhelm, William G. (Cutchogue, NY)

    1985-01-01

    This invention pertains to energy absorbers for solar collectors, and more particularly to high performance thin film absorbers. The solar collectors comprising the absorber of this invention overcome several problems seen in current systems, such as excessive hardware, high cost and unreliability. In the preferred form, the apparatus features a substantially rigid planar frame with a thin film window bonded to one planar side of the frame. An absorber in accordance with the present invention is comprised of two thin film layers that are sealed perimetrically. In a preferred embodiment, thin film layers are formed from a metal/plastic laminate. The layers define a fluid-tight planar envelope of large surface area to volume through which a heat transfer fluid flows. The absorber is bonded to the other planar side of the frame. The thin film construction of the absorber assures substantially full envelope wetting and thus good efficiency. The window and absorber films stress the frame adding to the overall strength of the collector.

  4. The nonlinear piezoelectric tuned vibration absorber

    NASA Astrophysics Data System (ADS)

    Soltani, P.; Kerschen, G.

    2015-07-01

    This paper proposes a piezoelectric vibration absorber, termed the nonlinear piezoelectric tuned vibration absorber (NPTVA), for the mitigation of nonlinear resonances of mechanical systems. The new feature of the NPTVA is that its nonlinear restoring force is designed according to a principle of similarity, i.e., the NPTVA should be an electrical analog of the nonlinear host system. Analytical formulas for the NPTVA parameters are derived using the homotopy perturbation method. Doing so, a nonlinear generalization of Den Hartog’s equal-peak tuning rule is developed for piezoelectric vibration absorbers.

  5. WARM GAS IN THE VIRGO CLUSTER. I. DISTRIBUTION OF Ly{alpha} ABSORBERS

    SciTech Connect

    Yoon, Joo Heon; Putman, Mary E.; Bryan, Greg L. [Department of Astronomy, Columbia University, New York, NY 10027 (United States); Thom, Christopher [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21211 (United States); Chen, Hsiao-Wen, E-mail: jhyoon@astro.columbia.edu [Department of Astronomy and Astrophysics and Kavli Institute for Cosmological Physics, University of Chicago, Chicago, IL 60637 (United States)

    2012-08-01

    The first systematic study of the warm gas (T = 10{sup 4-5} K) distribution across a galaxy cluster is presented using multiple background QSOs in and around the Virgo Cluster. We detect 25 Ly{alpha} absorbers (N{sub HI} = 10{sup 13.1-15.4} cm{sup -2}) in the Virgo velocity range toward 9 of 12 QSO sightlines observed with the Cosmic Origin Spectrograph, with a cluster impact parameter range of 0.36-1.65 Mpc (0.23-1.05 R{sub vir}). Including 18 Ly{alpha} absorbers previously detected by STIS or GHRS toward 7 of 11 background QSOs in and around the Virgo Cluster, we establish a sample of 43 absorbers toward a total of 23 background probes for studying the incidence of Ly{alpha} absorbers in and around the Virgo Cluster. With these absorbers, we find (1) warm gas is predominantly in the outskirts of the cluster and avoids the X-ray-detected hot intracluster medium (ICM). Also, Ly{alpha} absorption strength increases with cluster impact parameter. (2) Ly{alpha}-absorbing warm gas traces cold H I-emitting gas in the substructures of the Virgo Cluster. (3) Including the absorbers associated with the surrounding substructures, the warm gas covering fraction (100% for N{sub HI} > 10{sup 13.1} cm{sup -2}) is in agreement with cosmological simulations. We speculate that the observed warm gas is part of large-scale gas flows feeding the cluster both in the ICM and galaxies.

  6. Are strong z 0.5 MgII absorbers the signature of super-winds?

    NASA Astrophysics Data System (ADS)

    Bouché, N.; Murphy, M.; Péroux, C.; Csabai, I.; Wild, V.

    2007-05-01

    Starburst driven super-winds are known to be necessary in shaping the galaxy luminosity function and/or the mass-metallicity relation. Local starbursts show that the bulk of the flow (by mass) is in a `cold' phase medium entrained by the hot wind. At z=0.5--1, starbursts were more common and numerous, and the cold component of these outflows ought to contribute to the QSO-absorber cross-section. In fact, strong MgII absorbers have physical properties much alike those of starburst winds. Strong Mg II qso-absorbers (with 2796 rest-frame equivalent widths Wr>0.3 Angstrom) are made of several sub-components (`clouds') spreads over large velocities: 50-400 km/s, typical of outflows. The alternative scenario for MgII absorbers is that they are a signature of infalling gas, in which case the gas clouds would be virialized. We find that the absorber halo-mass is anti-correlated with the equivalent width Wr, which shows -for the first time- that the MgII clouds are not virialized in the gaseous halos of the host-galaxies. If Mg II absorbers were virialized in galaxy halos, a positive M—Wr correlation would have been observed because equivalent width is a direct measure of the velocity spread. The Mass—Velocity anti-correlation makes sense in the context of the starburst scenario where MgII absorbers are produced by supernovae-driven winds. The mean halo-mass of z˜0.5 Mg II qso-absorbers is measured from the cross-correlation (over co-moving scales 0.05—13 Mpc) between 1806 Mg II quasar absorption systems and ˜250,000 Luminous Red Galaxies (LRGs), both selected from the Sloan Digital Sky Survey Data Release 3. This statistical technique does not require any spectroscopic follow-up, and does not suffer from contaminants such as stars or foreground and background galaxies. Follow-up studies of M82-like starbursts are now possible up to z=2 thanks to the SDSS database and our MgII results.

  7. Attenuation of external Bremsstrahlung in metallic absorbers

    SciTech Connect

    Dhaliwal, A.S.; Powar, M.S.; Singh, M. (Punjabi Univ., Physics Dept., Patiala 147002 (IN))

    1990-12-01

    In this paper attenuation of bremsstrahlung from {sup 147}Pm and {sup 170}Tm beta emitters has been studied in aluminum, copper, tin, and lead metallic absorbers. Bremsstrahlung spectra and mass attenuation coefficients for monoenergetic gamma rays are used to calculate theoretical attenuation curves. Magnetic deflection and beta stopping techniques are used to measure the integral bremsstrahlung intensities above 30 keV in different target thicknesses. Comparison of measured and calculated attenuation curves shows a good agreement for various absorbers, thus providing a test of this technique, which may be useful in understanding bremsstrahlung intensity buildup and in the design of optimum shielding for bremsstrahlung sources. It is found that the absorption of bremsstrahlung in metallic absorbers does not obey an exponential law and that absorbers act as energy filters.

  8. 21 CFR 872.6050 - Saliva absorber.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Miscellaneous Devices § 872.6050 Saliva...intended to absorb moisture from the oral cavity during dental procedures. (b) Classification....

  9. 21 CFR 872.6050 - Saliva absorber.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Miscellaneous Devices § 872.6050 Saliva...intended to absorb moisture from the oral cavity during dental procedures. (b) Classification....

  10. 21 CFR 872.6050 - Saliva absorber.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Miscellaneous Devices § 872.6050 Saliva...intended to absorb moisture from the oral cavity during dental procedures. (b) Classification....

  11. 21 CFR 872.6050 - Saliva absorber.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Miscellaneous Devices § 872.6050 Saliva...intended to absorb moisture from the oral cavity during dental procedures. (b) Classification....

  12. 21 CFR 872.6050 - Saliva absorber.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Miscellaneous Devices § 872.6050 Saliva...intended to absorb moisture from the oral cavity during dental procedures. (b) Classification....

  13. A broadband planar THz metamaterial absorber

    NASA Astrophysics Data System (ADS)

    Xu, Zong-Cheng; Gao, Run-Mei; Ding, Chun-Feng; Zhang, Ya-Ting; Wu, Liang; Xu, De-Gang; Yao, Jian-Quan

    2015-05-01

    We propose the design of a broadband planar metamaterial absorber (MA) at terahertz frequencies. The unit cell of the MA is composed of four dual-band sub-cells with different dimensions in a coplanar. The four dual-band sub-cell structures resonate at several neighboring frequencies. The absorber consists of two metallic layers separated by a dielectric spacer. Simulation results show that the metamaterial absorption at normal incidence is above 90% in the frequency of 6.56-8.10 THz. This design provides an effective way to construct broadband absorber. The multiple-reflection theory was used to explain the absorption mechanism of our investigated structures. The coupling of adjacent four dual-band sub-cells can introduce additional capacitance to affect the performance of absorber.

  14. Neutron absorbing coating for nuclear criticality control

    DOEpatents

    Mizia, Ronald E. (Idaho Falls, ID); Wright, Richard N. (Idaho Falls, ID); Swank, William D. (Idaho Falls, ID); Lister, Tedd E. (Idaho Falls, ID); Pinhero, Patrick J. (Idaho Falls, ID)

    2007-10-23

    A neutron absorbing coating for use on a substrate, and which provides nuclear criticality control is described and which includes a nickel, chromium, molybdenum, and gadolinium alloy having less than about 5% boron, by weight.

  15. Radial cold trap

    DOEpatents

    Grundy, B.R.

    1981-09-29

    The radial cold trap comprises a housing having a plurality of mesh bands disposed therein. The mesh bands comprise concentrically arranged bands of mesh with the mesh specific surface area of each band increasing from the outermost mesh band to the innermost mesh band. An inlet nozzle is attached to the outside section of the housing while an outlet nozzle is attached to the inner portion of the housing so as to be concentrically connected to the innermost mesh band. An inlet baffle having orifices therein may be disposed around the outermost mesh band and within the housing for directing the flow of the fluid from the inlet nozzle to the outermost mesh band in a uniform manner. The flow of fluid passes through each consecutive mesh band and into the outlet nozzle. The circular pattern of the symmetrically arranged mesh packing allows for better utilization of the entire cold trap volume. 2 figs.

  16. Porous absorber for solar air heaters

    SciTech Connect

    Finch, J.A.

    1980-09-10

    A general discussion of the factors affecting solar collector performance is presented. Bench scale tests done to try to determine the heat transfer characteristics of various screen materials are explained. The design, performance, and evaluation of a crude collector with a simple screen stack absorber is treated. The more sophisticated absorber concept, and its first experimental approximation is examined. A short summary of future plans for the collector concept is included. (MHR)

  17. 21 CFR 886.3300 - Absorbable implant (scleral buckling method).

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...2010-04-01 2010-04-01 false Absorbable implant (scleral buckling method...Prosthetic Devices § 886.3300 Absorbable implant (scleral buckling method). (a) Identification. An absorbable implant (scleral buckling...

  18. 21 CFR 880.5300 - Medical absorbent fiber.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...2013-04-01 false Medical absorbent fiber. 880.5300 Section 880.5300 Food...Devices § 880.5300 Medical absorbent fiber. (a) Identification. A medical absorbent fiber is a device intended for medical...

  19. 21 CFR 880.5300 - Medical absorbent fiber.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...2012-04-01 false Medical absorbent fiber. 880.5300 Section 880.5300 Food...Devices § 880.5300 Medical absorbent fiber. (a) Identification. A medical absorbent fiber is a device intended for medical...

  20. 21 CFR 880.5300 - Medical absorbent fiber.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...2014-04-01 false Medical absorbent fiber. 880.5300 Section 880.5300 Food...Devices § 880.5300 Medical absorbent fiber. (a) Identification. A medical absorbent fiber is a device intended for medical...

  1. Cold cathodes for CFAs

    Microsoft Academic Search

    K. F. Ramacher; M. S. Worthington; G. R. MacPhail

    2000-01-01

    Summary form only given. Application of cold cathode technology for use in crossed-field amplifiers (CFAs) has been limited by the characteristics of the materials, usually platinum (Pt) or beryllium (Be\\/BeO), used as the emitter. A case in point is the L-4717, used as the second stage amplifier (baby Amplitron) in the SPS-48-C\\/E transmitters. This tube, which uses a thermionic emitter,

  2. Cold nuclear fusion

    SciTech Connect

    Tsyganov, E. N., E-mail: edward.tsyganov@utsouthwestern.edu [University of Texas Southwestern Medical Center at Dallas (United States)

    2012-02-15

    Recent accelerator experiments on fusion of various elements have clearly demonstrated that the effective cross-sections of these reactions depend on what material the target particle is placed in. In these experiments, there was a significant increase in the probability of interaction when target nuclei are imbedded in a conducting crystal or are a part of it. These experiments open a new perspective on the problem of so-called cold nuclear fusion.

  3. Crazy Cold Air

    NSDL National Science Digital Library

    In this classroom activity, students record the temperatures in and around a walk-in refrigerator or freezer to see how cold air behaves when it meets warmer air. The printable five-page handout includes a series of inquiry-based questions to get students thinking about how the temperature of air changes its density, detailed experiment directions and a worksheet that helps students use the experiment results to obtain insight into the wind patterns of Antarctica.

  4. Full calculation of clumpiness boost factors for antimatter cosmic rays in the light of Lambda-CDM N-body simulation results

    E-print Network

    J. Lavalle; Q. Yuan; D. Maurin; X. -J. Bi

    2008-02-14

    Anti-proton and positron Galactic cosmic ray spectra are among the key targets for indirect detection of dark matter. The boost factors, corresponding to an enhancement of the signal and linked to the clumpiness properties of the dark matter distribution, have been taken as high as thousands in the past. The dramatic impact of these boost factors for indirect detection of antiparticles, for instance with the PAMELA satellite or the coming AMS-02 experiment, asks for their detailed calculation. We take into account the results of high resolution N-body dark matter simulations to calculate the most likely energy dependent boost factors linked to the cosmic ray propagation properties, for anti-protons and positrons. Starting from the mass and space distributions of sub-halos, the anti-proton and positron propagators are used to calculate the mean value and the variance of the boost factor for the primary fluxes. We take advantage of the statistical method introduced in Lavalle et al. (2007) and cross-check the results with Monte Carlo computations. By spanning some extreme configurations of sub-halo and propagation properties, we find that the average contribution of the clumps is negligible compared to that of the smooth dark matter component. Sub-halos do not lead to enhancement of the signals, unless they are taken with some extreme (unexpected) properties. This result is independent of the nature of the self-annihilating dark matter candidate considered, and provides precise estimates of the theoretical and the statistical uncertainties of the antimatter flux from dark matter substructures. Spectral distortions can still be expected in antimatter flux measurements, but scenarios invoking large and even mild clumpiness boost factors are strongly disfavoured by our analysis.

  5. Absorbance changes of carotenoids in different solvents.

    PubMed

    Zang, L Y; Sommerburg, O; van Kuijk, F J

    1997-01-01

    Carotenoids are typically measured in tissues with the high performance liquid chromatography (HPLC) and quantitation is usually done by calibrating with stock solutions in solvents. Four carotenoids including lutein, zeaxanthin, lycopene and beta-carotene were dissolved in hexane and methanol respectively, and their absorbance characteristics were compared. Lutein shows absorbance spectra that are almost independent of solvents at various concentrations. Spectra of zeaxanthin, lycopene and beta-carotene were found to be more solvent-dependent. The absorbance of zeaxanthin at lambda max is about approximately 2 times larger in methanol than in hexane at the higher concentrations, and increased non-linearly with increasing concentration in hexane. The absorbance of lycopene at lambda max in hexane is approximately 4 fold larger than in methanol, but the absorbance of the methanol sample can be recovered by re-extracting this sample in hexane. The absorbance of beta-carotene in hexane is larger than in methanol, and increased linearly with increasing concentration. But beta-carotene showed a non-linear concentration effect in methanol. There are very small variations in lambda max for all four carotenoids between hexane and methanol, due to differences in molar extinction coefficients. The non-linear concentration effects for these carotenoids are probably due to differences in solubility leading to the formation of microcrystals. Thus, care should be taken with quantitation of tissue carotenoid values, when they depend on measurement of concentrations in stock solutions. PMID:9358253

  6. Tuned vibration absorbers for offshore structures

    SciTech Connect

    Dimentberg, M.F.; Hou, Z.; Noori, M.N.; Chen, S. [Worcester Polytechnic Inst., MA (United States). Dept. of Mechanical Engineering

    1996-12-31

    A preliminary feasibility study is made of efficiency of tuned vibration absorbers for reducing response of offshore platforms, to random ocean waves. The absorbers are submerged spring-loaded flaps, with stiffnesses of the springs being adjusted for tuning to any specific (rigid-body) mode of the platform (heaving, pitching, etc.), whereas actual design of the flaps should provide the desired amount of drag-induced damping. Mean square response analysis of the system is made for the case of a narrow-band random excitation due to ocean waves by using method of moments in conjunction with statistical linearization (with Gaussian closure) for quadratic damping term. Extensive parametric study is made of the efficiency of vibration control through the use of absorbers, as represented by the RMS response reduction factor. In particular, the efficiency increases with the absorber/platform mass ratio, and it may be of some practical importance even at values of this ratio as small as one percent. The importance of the excitation bandwidth is demonstrated. It is shown also, that whereas optimal damping of the absorber depends on the level of wave excitation, the RMS response reduction is fairly constant within a rather broad range of (nonlinear) damping, so that adjusting absorber damping for storm level may not be necessary.

  7. Perfect terahertz absorber using fishnet based metafilm

    SciTech Connect

    Azad, Abul Kalam [Los Alamos National Laboratory; Shchegolkov, Dmitry Yu [Los Alamos National Laboratory; Chen, Houtong [Los Alamos National Laboratory; Taylor, Antoinette [Los Alamos National Laboratory; Smirnova, E I [Los Alamos National Laboratory; O' Hara, John F [Los Alamos National Laboratory

    2009-01-01

    We present a perfect terahertz (THz) absorber working for a broad-angle of incidence. The two fold symmetry of rectangular fishnet structure allows either complete absorption or mirror like reflection depending on the polarization of incident the THz beam. Metamaterials enable the ability to control the electromagnetic wave in a unique fashion by designing the permittivity or permeability of composite materials with desired values. Although the initial idea of metamaterials was to obtain a negative index medium, however, the evolution of metamaterials (MMs) offers a variety of practically applicable devices for controlling electromagnetic wave such as tunable filters, modulators, phase shifters, compact antenna, absorbers, etc. Terahertz regime, a crucial domain of the electromagnetic wave, is suffering from the scarcity of the efficient devices and might take the advantage of metamaterials. Here, we demonstrate design, fabrication, and characterization of a terahertz absorber based on a simple fishnet metallic film separated from a ground mirror plane by a dielectric spacer. Such absorbers are in particular important for bolometric terahertz detectors, high sensitivity imaging, and terahertz anechoic chambers. Recently, split-ring-resonators (SRR) have been employed for metamaterial-based absorbers at microwave and THz frequencies. The experimental demonstration reveals that such absorbers have absorptivity close to unity at resonance frequencies. However, the downside of these designs is that they all employ resonators of rather complicated shape with many fine parts and so they are not easy to fabricate and are sensitive to distortions.

  8. Cold Stowage Flight Systems

    NASA Technical Reports Server (NTRS)

    Campana, Sharon E.; Melendez, David T.

    2011-01-01

    The International Space Station (ISS) provides a test bed for researchers to perform science experiments in a variety of fields, including human research, life sciences, and space medicine. Many of the experiments being conducted today require science samples to be stored and transported in a temperature controlled environment. NASA provides several systems which aid researchers in preserving their science. On orbit systems provided by NASA include the Minus Eighty Laboratory freezer for ISS (MELFI), Microgravity Experiment Research Locker Incubator (MERLIN), and Glacier. These freezers use different technologies to provide rapid cooling and cold stowage at different temperature levels on board ISS. Systems available to researchers during transportation to and from ISS are MERLIN, Glacier, and Coldbag. Coldbag is a passive cold stowage system that uses phase change materials to maintain temperature. Details of these current technologies are provided along with operational experience gained to date. This paper discusses the capability of the current cold stowage hardware and how it may continue to support NASA s mission on ISS and in future exploration missions.

  9. Cold Stowage Flight Systems

    NASA Technical Reports Server (NTRS)

    Campana, Sharon

    2010-01-01

    The International Space Station (ISS) provides a test bed for researchers to perform science experiments in a variety of fields, including human research, life sciences, and space medicine. Many of the experiments being conducted today require science samples to be stored and transported in a temperature controlled environment. NASA provides several systems which aide researchers in preserving their science. On orbit systems provided by NASA include the Minus Eighty Laboratory freezer for ISS (MELFI), Microgravity Experiment Research Locker Incubator (MERLIN), and Glacier. These freezers use different technologies to provide rapid cooling and cold stowage at different temperature levels on board ISS. Systems available to researchers during transportation to and from ISS are MERLIN, Glacier, and Coldbag. Coldbag is a passive cold stowage system that uses phase change materials. Details of these current technologies will be provided along with operational experience gained to date. With shuttle retirement looming, NASA has protected the capability to provide a temperature controlled environment during transportation to and from the ISS with the use of Glacier and Coldbags, which are compatible with future commercial vehicles including SpaceX's Dragon Capsule, and Orbital s Cygnus vehicle. This paper will discuss the capability of the current cold stowage hardware and how it may continue to support NASA s mission on ISS and in future exploration missions.

  10. In vivo absorbance spectra and the ecophysiology of reef macroalgae

    Microsoft Academic Search

    K. S. Beach; H. B. Borgeas; N. J. Nishimura; C. M. Smith

    1997-01-01

    .  ?In vivo absorbance spectra were obtained for 12 species of tropical macroalgae. Absorbance of UV irradiance was greater than\\u000a absorbance of photosynthetically active radiation in most algal taxa. UV irradiance may be pre-emptively captured by UV absorbing\\u000a compounds as indicated by the significant relationship between in vivo and extract absorbance characteristics. In vivo and\\u000a extract absorbance characteristics indicated that concentrations

  11. X-raying the Intergalactic OVI Absorbers

    E-print Network

    Y. Yao; T. M. Tripp; Q. D. Wang; C. W. Danforth; C. R. Canizares; J. M. Shull; H. L. Marshall; L. Song

    2009-03-23

    The observed intergalactic OVI absorbers at z>0 have been regarded as a significant reservoir of the ``missing baryons''. However, to fully understand how these absorbers contribute to the baryon inventory, it is crucial to determine whether the systems are collisionally ionized or photoionized (or both). Using the identified intergalactic OVI absorbers as tracers, we search for the corresponding X-ray absorption lines, which are useful for finding the missing baryons and for revealing the nature of the OVI absorbers. Stacking the Chandra grating spectra along six AGN sight lines, we obtain three spectra with signal-to-noise ratios of 32, 28, and 10 per 12.5 mA spectral bin around the expected OVII Kalpha wavelength. These spectra correspond to OVI absorbers with various dynamic properties. We find no detectable NeIX, OVII, OVIII, NVII, or CVI absorption lines in the spectra, but the high counting statistics allows us to obtain firm upper limits on the corresponding ionic column densities (in particular N(OVII)<=10 N(OVI) on average at the 95% confidence level). Jointly analyzing these non-detected X-ray lines with the averaged OVI column density, we further limit the average temperature of the OVI-bearing gas to be log[T(K)]<=5.7 in collisional ionization equilibrium. We discuss the implications of these results for physical properties of the putative warm-hot intergalactic medium and its detection in future X-ray observations.

  12. Ultrathin flexible dual band terahertz absorber

    NASA Astrophysics Data System (ADS)

    Shan, Yan; Chen, Lin; Shi, Cheng; Cheng, Zhaoxiang; Zang, Xiaofei; Xu, Boqing; Zhu, Yiming

    2015-09-01

    We propose an ultrathin and flexible dual band absorber operated at terahertz frequencies based on metamaterial. The metamaterial structure consists of periodical split ring resonators with two asymmetric gaps and a metallic ground plane, separated by a thin-flexible dielectric spacer. Particularly, the dielectric spacer is a free-standing polyimide film with thickness of 25 ?m, resulting in highly flexible for our absorber and making it promising for non-planar applications such as micro-bolometers and stealth aircraft. Experimental results show that the absorber has two resonant absorption frequencies (0.41 THz and 0.75 THz) with absorption rates 92.2% and 97.4%, respectively. The resonances at the absorption frequencies come from normal dipole resonance and high-order dipole resonance which is inaccessible in the symmetrical structure. Multiple reflection interference theory is used to analyze the mechanism of the absorber and the results are in good agreement with simulated and experimental results. Furthermore, the absorption properties are studied under various spacer thicknesses. This kind of metamaterial absorber is insensitive to polarization, has high absorption rates (over 90%) with wide incident angles range from 0° to 45° and the absorption rates are also above 90% when wrapping it to a curved surface.

  13. Peregrinations on cold fusion

    SciTech Connect

    Turner, L.

    1989-01-01

    Attention is focused on the possibility of resonance-enhanced deuteron Coulomb barrier penetration. Because of the many-body nature of the interactions of room-temperature deuterons diffusing through a lattice possessing deuterons in many of the interstitial positions, the diffusing deuterons can resonate on the atomic scale in the potential wells bounded by the ascending walls of adjacent Coulomb barriers and thereby penetrate the Coulomb barriers in a fashion vastly underestimated by two-body calculations in which wells for possible resonance are absent. Indeed, perhaps the lack of robust reproducibility in cold fusion originates from the narrowness of such transmission resonances. 4 refs., 1 fig.

  14. The Isis cold moderators

    SciTech Connect

    Allen, G. M.; Broome, T. A.; Burridge, R. A.; Cragg, D.; Hall, R.; Haynes, D.; Hirst, J.; Hogston, J. R.; Jones, H. H.; Sexton, J.; Wright, P.

    1997-09-01

    ISIS is a pulsed spallation neutron source where neutrons are produced by the interaction of a 160 kW proton beam of energy 800 MeV in a water-cooled Tantalum Target. The fast neutrons produced are thermalized in four moderators: two ambient water, one liquid methane operating at 100K and a liquid hydrogen moderator at 20 K. This paper gives a description of the construction of both cold moderator systems, details of the operating experience and a description of the current development program.

  15. Photoexited switchable metamaterial absorber at terahertz frequencies

    NASA Astrophysics Data System (ADS)

    Xu, Zongcheng; Gao, Runmei; Ding, Chunfeng; Wu, Liang; Zhang, Yating; Xu, Degang; Yao, Jianquan

    2015-06-01

    We propose a design and numerical study of an optically switchable metamaterial absorber in the terahertz regime. The metamaterial absorber comprises a periodic array of metallic split-ring resonators sitting back to back with an embedded semiconductor silicon. Filing the gap between the resonator arms with a semiconductor (silicon), leads to easy modification of its optical response through a pump beam which changes conductivity of Si. The conductivity of silicon is a function of incident pump power. Therefore, the resonance frequencies of the metamaterial can be tunable by applying an external pump power. The resonance peak of the absorption spectra shows a shift from 1.17 to 0.68 THz via external optical stimulus, with granting a resonance tuning range on the order of 42%. The optical-tuned absorber has potential applications as a terahertz modulator and switchable device and offer a step forward in filling the "THz gap".

  16. Optical analysis of solar energy tubular absorbers.

    PubMed

    Saltiel, C; Sokolov, M

    1982-11-15

    The energy absorbed by a solar energy tubular receiver element for a single incident ray is derived. Two types of receiver elements were analyzed: (1) an inner tube with an absorbing coating surrounded by a semitransparent cover tube, and (2) a semitransparent inner tube filled with an absorbing fluid surrounded by a semitransparent cover tube. The formation of ray cascades in the semitransparent tubes is considered. A numerical simulation to investigate the influence of the angle of incidence, sizing, thickness, and coefficient of extinction of the tubes was performed. A comparison was made between receiver elements with and without cover tubes. Ray tracing analyses in which rays were followed within the tubular receiver element as well as throughout the rest of the collector were performed for parabolic and circular trough concentrating collectors. PMID:20401004

  17. Absorber Materials at Room and Cryogenic Temperatures

    SciTech Connect

    F. Marhauser, T.S. Elliott, A.T. Wu, E.P. Chojnacki, E. Savrun

    2011-09-01

    We recently reported on investigations of RF absorber materials at cryogenic temperatures conducted at Jefferson Laboratory (JLab). The work was initiated to find a replacement material for the 2 Kelvin low power waveguide Higher Order Mode (HOM) absorbers employed within the original cavity cryomodules of the Continuous Electron Beam Accelerator Facility (CEBAF). This effort eventually led to suitable candidates as reported in this paper. Furthermore, though constrained by small funds for labor and resources, we have analyzed a variety of lossy ceramic materials, several of which could be usable as HOM absorbers for both normal conducting and superconducting RF structures, e.g. as loads in cavity waveguides and beam tubes either at room or cryogenic temperatures and, depending on cooling measures, low to high operational power levels.

  18. Locking mechanism strength of absorbable ligating devices.

    PubMed

    Hay, D L; von Fraunhofer, J A; Chegini, N; Masterson, B J

    1988-03-01

    The locking mechanism strengths of the absorbable Absolok and Lactomer ligating clips and the absorbable Lactomer staple have been determined following implantation in an animal model. Three sizes of each type of clip and the single size of staple were enclosed in open mesh nylon pouches and implanted subcutaneously in rabbits for periods of 4, 7, 14, 21, and 28 days before tensile testing of the lock mechanisms. No change in the lock mechanism strength was detected for the Absolok clips before 21 days. The Lactomer clips and staples, however, showed significant decrease in lock mechanism strength within 7 days of implantation, this loss increasing with longer implantation times. A proportion of all the devices were found to have dissolved to an extent that precluded testing at 21 and 28 days. The findings indicate that the lock mechanisms of absorbable ligating clips differ significantly in their short-term (30 days) durability. PMID:3360813

  19. Ferrite HOM Absorber for the RHIC ERL

    SciTech Connect

    Hahn,H.; Choi, E.M.; Hammons, L.

    2008-10-01

    A superconducting Energy Recovery Linac is under construction at Brookhaven National Laboratory to serve as test bed for RHIC upgrades. The damping of higher-order modes in the superconducting five-cell cavity for the Energy-Recovery linac at RHIC is performed exclusively by two ferrite absorbers. The ferrite properties have been measured in ferrite-loaded pill box cavities resulting in the permeability values given by a first-order Debye model for the tiled absorber structure and an equivalent permeability value for computer simulations with solid ring dampers. Measured and simulated results for the higher-order modes in the prototype copper cavity are discussed. First room-temperature measurements of the finished niobium cavity are presented which confirm the effective damping of higher-order modes in the ERL. by the ferrite absorbers.

  20. RADIATIVE TRANSFER IN A CLUMPY UNIVERSE. IV. NEW SYNTHESIS MODELS OF THE COSMIC UV/X-RAY BACKGROUND

    SciTech Connect

    Haardt, Francesco [Dipartimento di Scienza e alta Tecnologia, Universita dell'Insubria, via Valleggio 11, 22100 Como (Italy); Madau, Piero, E-mail: haardt@uninsubria.it, E-mail: pmadau@ucolick.org [Department of Astronomy and Astrophysics, University of California, 1156 High Street, Santa Cruz, CA 95064 (United States)

    2012-02-20

    We present improved synthesis models of the evolving spectrum of the UV/X-ray diffuse background, updating and extending our previous results. Five new main components are added to our radiative transfer code CUBA: (1) the sawtooth modulation of the background intensity from resonant line absorption in the Lyman series of cosmic hydrogen and helium; (2) the X-ray emission from the obscured and unobscured quasars that gives origin to the X-ray background; (3) a piecewise parameterization of the distribution in redshift and column density of intergalactic absorbers that fits recent measurements of the mean free path of 1 ryd photons; (4) an accurate treatment of the photoionization structure of absorbers, which enters in the calculation of the helium continuum opacity and recombination emissivity; and (5) the UV emission from star-forming galaxies at all redshifts. We provide tables of the predicted H I and He II photoionization and photoheating rates for use, e.g., in cosmological hydrodynamics simulations of the Ly{alpha} forest and a new metallicity-dependent calibration to the UV luminosity density-star formation rate density relation. A 'minimal cosmic reionization model' is also presented in which the galaxy UV emissivity traces recent determinations of the cosmic history of star formation, the luminosity-weighted escape fraction of hydrogen-ionizing radiation increases rapidly with look-back time, the clumping factor of the high-redshift intergalactic medium evolves following the results of hydrodynamic simulations, and Population III stars and miniquasars make a negligible contribution to the metagalactic flux. The model provides a good fit to the hydrogen-ionization rates inferred from flux decrement and proximity effect measurements, predicts that cosmological H II (He III) regions overlap at redshift 6.7 (2.8), and yields an optical depth to Thomson scattering, {tau}{sub es} = 0.084 that is in agreement with Wilkinson Microwave Anisotropy Probe results. Our new background intensities and spectra are sensitive to a number of poorly determined input parameters and suffer from various degeneracies. Their predictive power should be constantly tested against new observations. We are therefore making our redshift-dependent UV/X emissivities and CUBA outputs freely available for public use at http://www.ucolick.org/{approx}pmadau/CUBA.

  1. Cold molecular gas and history of the Universe.

    NASA Astrophysics Data System (ADS)

    Combes, F.; Wiklind, T.

    1997-09-01

    Molecular absorption in front of radio-loud quasars is a unique tool to probe cold gas at high redshifts, with the benefit of high angular and velocity resolutions. Molecular abundances, and excitation temperatures can be studied at length in remote galaxies. The diffuse components allow to obtain an upper limit on the temperature of the cosmic background radiation as a function of redshift. Since the cross-section for absorption is very small around a galaxy, the absorbing systems are either internal, or coming from a gravitational lens. The molecular measurements can then contribute to cosmological determination.

  2. Study of fast neutron radiation effects in cold moderator materials

    E-print Network

    Shabalin, E P; Kulagin, E N; Kulikov, S A; Melikhov, V V

    2002-01-01

    A phenomenon of spontaneous release of energy accumulated in some hydrogenous materials under fast neutron irradiation at low temperature was studied at a cryogenic irradiation facility of the IBR-2 reactor in Dubna for the purpose of cold neutron moderator development. Spontaneous release of energy occurred in water ice after 5 - 11 h of fast neutron irradiation at a temperature of less than 34 K and at an absorbed dose rate of 0.4 MGy/h. In contrast with previous data, no spontaneous burp was observed in solid methane

  3. Design aspects of vertical wave absorbers

    SciTech Connect

    Clauss, G.F.; Kuhlmann, G.H. [Technical Univ. of Berlin (Germany). Inst. of Naval Architecture and Ocean Engineering

    1995-12-31

    This paper presents a new numerical procedure for the analysis of multi-row wave absorbers with selected porosities of individual elements. The theoretical model is based on the calculation of the energy flux, i.e. the analysis of transmission, reflection and the energy dissipation at successive rows using the impulse response function. Empirical coefficients obtained from experiments with single screens are used in the numerical treatment of absorbers consisting of an array of screens. The analysis is backed up by an experimental program which investigates the reflection and transmission characteristics of porous walls in encountering wave groups as well as in transient wave trains representing a design wave spectrum.

  4. SELECTIVE ABSORBER COATED FOILS FOR SOLAR COLLECTORS

    SciTech Connect

    Lampert, Carl M.

    1980-04-01

    Solar absorber metal foils are discussed in terms of materials and basic processing science. Also included is the use of finished heavy sheet stock for direct fabrication of solar collector panels. Both the adhesives and bonding methods for foils and sheet are surveyed. Developmental and representative commercial foils are used as illustrative examples. As a result it was found that foils can compete economically with batch plating but are limited by adhesive temperature stability. Also absorber foils are very versatile and direct collector fabrication from heavy foils appears very promising.

  5. Advection diffusion equation with absorbing boundary

    E-print Network

    John Grant; Michael Wilkinson

    2014-12-15

    We consider a spatially homogeneous advection-diffusion equation in which the diffusion tensor and drift velocity are time-independent, but otherwise general. We derive asymptotic expressions, valid at large distances from a steady point source, for the flux onto a completely permeable boundary and onto an absorbing boundary. The absorbing case is treated by making a source of antiparticles at the boundary. In both cases there is an exponential decay as the distance from the source increases; we find that the exponent is the same for both boundary conditions.

  6. OSCEE fan exhaust bulk absorber treatment evaluation

    NASA Technical Reports Server (NTRS)

    Bloomer, H. E.; Samanich, N. E.

    1980-01-01

    The acoustic suppression capability of bulk absorber material designed for use in the fan exhaust duct walls of the quiet clean short haul experiment engine (OCSEE UTW) was evaluated. The acoustic suppression to the original design for the engine fan duct which consisted of phased single degree-of-freedom wall treatment was tested with a splitter and also with the splitter removed. Peak suppression was about as predicted with the bulk absorber configuration, however, the broadband characteristics were not attained. Post test inspection revealed surface oil contamination on the bulk material which could have caused the loss in bandwidth suppression.

  7. Method for manufacture of neutron absorbing articles

    SciTech Connect

    Owens, D.

    1980-07-22

    A one-step curing method for the manufacture of a neutron absorbing article which comprises irreversibly curing, in desired article form, a form-retaining mixture of boron carbide particles, curable phenolic resin in solid state and in particula te form and a minor proportion of a liquid medium, which boils at a temperature below 200*c., at an elevated temperature so as to obtain bonding of the irreversibly cured phenolic polymer resulting to the boron carbide particles and production of the neutron absorbing article in desired form.

  8. The MIRD method of estimating absorbed dose

    SciTech Connect

    Weber, D.A.

    1991-01-01

    The estimate of absorbed radiation dose from internal emitters provides the information required to assess the radiation risk associated with the administration of radiopharmaceuticals for medical applications. The MIRD (Medical Internal Radiation Dose) system of dose calculation provides a systematic approach to combining the biologic distribution data and clearance data of radiopharmaceuticals and the physical properties of radionuclides to obtain dose estimates. This tutorial presents a review of the MIRD schema, the derivation of the equations used to calculate absorbed dose, and shows how the MIRD schema can be applied to estimate dose from radiopharmaceuticals used in nuclear medicine.

  9. CONTROLLABLE ABSORBING STRUCTURE OF METAMATERIAL AT MICROWAVE

    Microsoft Academic Search

    Zhanxian Xu; Weigan Lin; Lidu Kong

    2007-01-01

    Akind of controllable metamaterial absorbing structure is presented in this paper, both transmission coefficient and single radar cross section (RCS) are electrically controlled. This structure is composed from split ring resonators (SRRs) and metallic wire arrays including pin diodes, pin diodes are periodically inserted at these wire arrays discontinuous, and they can be either in an on state or in

  10. The design of broadband radar absorbing surfaces

    NASA Astrophysics Data System (ADS)

    Suk, Go H.

    1990-09-01

    There has been a growing and widespread interest in radar absorbing material technology. As the name implies, radar absorbing materials or RAM's are coatings whose electric and magnetic properties have been selected to allow the absorption of microwave energy at discrete or broadband frequencies. In military applications low radar cross section (RCS) of a vehicle may be required in order to escape detection while a covert mission is being carried on. These requirements have led to the very low observable or stealth technology that reduces the probability of detection of an aircraft. The design of radar absorbing materials is limited by constraints on the allowable volume and weight of the surface coating, and it is difficult to design a broadband radar absorbing structure in limited volume. This thesis investigates the use of lossy dielectric materials of high dielectric permittivity in multilayer composites for the production of low radar cross section (RCS). The analysis is done by computing the plane wave reflection coefficient at the exterior surface of the composite coating by means of a computer program which selects layer parameters which determine low reflection coefficients for electromagnetic radiation under constraint of limited layer thickness as well as maximum frequency bandwidth.

  11. Shock absorber protects motive components against overloads

    NASA Technical Reports Server (NTRS)

    1965-01-01

    Shock absorber with an output shaft, hollow gear, and a pair of springs forming a resilient driving connection between shaft and gear, operates when abnormally high torques are applied. This simple durable frictional device is valuable in rotating mechanisms subject to sudden overloads.

  12. Shock absorbing mount for electrical components

    NASA Technical Reports Server (NTRS)

    Dillon, R. F., Jr.; Mayne, R. C. (inventors)

    1975-01-01

    A shock mount for installing electrical components on circuit boards is described. The shock absorber is made of viscoelastic material which interconnects the electrical components. With this system, shocks imposed on one component of the circuit are not transmitted to other components. A diagram of a typical circuit is provided.

  13. Equivalence and optimization of absorbing boundary conditions

    Microsoft Academic Search

    Weiliang Yuan; Qinxi Chu; Changhong Liang

    1998-01-01

    Four types of absorbing boundary conditions (ABC) widely used in finite-difference time-domain (FDTD) simulations are discussed from the point of view of their equivalence. They include Mur's (1981) ABC, dispersive ABC, Liao's (1986) ABC and Higdon's (1986) operator, and an analytical expression of Liao's ABC is given. These ABCs are essentially equivalent and can be embodied by an analytical equation

  14. An analysis of Liao's absorbing boundary condition

    Microsoft Academic Search

    R. L. Wagner; W. C. Chew

    1995-01-01

    A theoretical and numerical analysis of Liao's absorbing boundary condition (ABC) is presented. The form of the ABC is related to both space-time polynomial extrapolation and a one-way wave equation. A modification allowing the optimization of the ABC for specific angles of incidence or wave speeds is discussed. The stability of the ABC is also discussed, and a technique is

  15. Oxygen Absorbers for Extension of Crackers Shelflife

    Microsoft Academic Search

    Sigalit Berenzon; I. Sam Saguy

    1998-01-01

    Applicability of oxygen absorbers for extending shelf-life of military ration crackers packaged in hermetically sealed tin cans and stored at 15, 25 and 35 °C for up to 52 weeks was assessed. Lipid oxidation began immediately after baking. Storage temperature was the major factor affecting the rate of oxygen depletion within the can. Residual headspace oxygen of the crackers stored

  16. Optimization and engineering of microwave absorbers

    Microsoft Academic Search

    Kuo-Liang Chen

    1998-01-01

    In this thesis, a concerted effort has been made to study and evaluate the individual electromagnetic properties of the absorbing components including carbon black, conducting fibers, metal flakes, magnetic materials such as carbonyl iron, ferrite and the chiral type of micro- carbon coil. The study of the electromagnetic properties covers functions such as dielectric dissipation, random scattering effect at low

  17. Aldehyde-containing urea-absorbing polysaccharides

    NASA Technical Reports Server (NTRS)

    Mueller, W. A.; Hsu, G. C.; Marsh, H. E., Jr. (inventors)

    1977-01-01

    A novel aldehyde containing polymer (ACP) is prepared by reaction of a polysaccharide with periodate to introduce aldehyde groups onto the C2 - C3 carbon atoms. By introduction of ether and ester groups onto the pendant primary hydroxyl solubility characteristics are modified. The ACP is utilized to absorb nitrogen bases such as urea in vitro or in vivo.

  18. Front End Chicane Chicane Geometry and Absorber

    E-print Network

    McDonald, Kirk

    National Laboratory MAP Front End Meeting 6 May 2014 #12;Introduction Mu onAccelera tor Program GoalMu onAccelera tor Program Front End Chicane Chicane Geometry and Absorber J. Scott Berg Brookhaven 2014 J. S. Berg | Chicane | MAP Front End (2) #12;Previous Status (1 April) Mu onAccelera tor Program

  19. On Delayed Choice and Contingent Absorber Experiments

    E-print Network

    R. E. Kastner

    2012-05-15

    It is pointed out that a slight variation on the Wheeler Delayed Choice Experiment presents the same challenge to orthodox quantum mechanics as Maudlin-type contingent absorber experiments present to the Transactional Interpretation (TI). Therefore, the latter cannot be used as a basis for refutation of TI.

  20. Approximating Resonances with the Complex Absorbing Potential ...

    E-print Network

    2005-10-25

    the fact that perturbation spectral theory for non-self-adjoint operators is a delicate ...... 1 + ir. = ?i r + e. ?i. 1 + ir 3. (52). Choose r = exp? r ? B. ?k for 0 ? r ? 1/C, .... variable representation — absorbing boundary condition Green's function.

  1. Light-absorbing impurities in Arctic snow

    Microsoft Academic Search

    S. J. Doherty; S. G. Warren; T. C. Grenfell; A. D. Clarke; R. E. Brandt

    2010-01-01

    Absorption of radiation by ice is extremely weak at visible and near-ultraviolet wavelengths, so small amounts of light-absorbing impurities in snow can dominate the ab- sorption of solar radiation at these wavelengths, reducing the albedo relative to that of pure snow, contributing to the surface energy budget and leading to earlier snowmelt. In this study Arctic snow is surveyed for

  2. Light-absorbing impurities in Arctic snow

    Microsoft Academic Search

    S. J. Doherty; S. G. Warren; T. C. Grenfell; A. D. Clarke; R. E. Brandt

    2010-01-01

    Absorption of radiation by ice is extremely weak at visible and near-ultraviolet wavelengths, so small amounts of light-absorbing impurities in snow can dominate the absorption of solar radiation at these wavelengths, reducing the albedo relative to that of pure snow, contributing to the surface energy budget and leading to earlier snowmelt. In this study Arctic snow is surveyed for its

  3. Cold Dark Matter Resuscitated?

    E-print Network

    Martin White; Douglas Scott; Joe Silk; Marc Davis

    1995-08-21

    The Cold Dark Matter (CDM) model has an elegant simplicitly which makes it very predictive, but when its parameters are fixed at their `canonical' values its predictions are in conflict with observational data. There is, however, much leeway in the initial conditions within the CDM framework. We advocate a re-examination of the CDM model, taking into account modest variation of parameters from their canonical values. We find that CDM models with $n=0.8$--0.9 and $h=0.45$--0.50 can fit the available data. Our ``best fit'' CDM model has $n=0.9$, $h=0.45$ and $C_2^{T}/C_2^{S}=0.7$. We discuss the current state of observations which could definitely rule out this model.

  4. Hot Planet - Cold Comfort

    NSDL National Science Digital Library

    This page features videos from the "Hot Planet- Cold Comfort" television episode, related website articles and a student activity. The videos explore how the Gulf Stream conveyor belt may shut down; how Arctic river runoff and Alaskan glacial melt are freshening the oceans; and how ocean sediments and ice cores are being studied to understand the Little Ice Age. The videos total approximately one hour in length. The website articles explore the Little Ice Age; how the Arctic functions as a global thermostat, affecting global weather patterns; and great moments in climate change. The student activity is about light absorbtion. The site also contains a challenge activity to find details in a painting that depict Little Ice Age living conditions.

  5. Monitoring the vaccine cold chain

    Microsoft Academic Search

    E Cheriyan

    1993-01-01

    Maintaining the vaccine cold chain is an essential part of a successful immunisation programme. A continuous electronic temperature monitor helped to identify breaks in the cold chain in the community and the study led to the issue of proper guidelines and replacement of faulty equipment.

  6. Encyclopedia of the Cold War

    Microsoft Academic Search

    Dijk van R

    2008-01-01

    Between 1945 and 1991, tension between the USA, its allies, and a group of nations led by the USSR, dominated world politics. This period was called the Cold War – a conflict that stopped short to a full-blown war. Benefiting from the recent research of newly open archives, the Encyclopedia of the Cold War discusses how this state of perpetual

  7. Tip model of cold fission

    Microsoft Academic Search

    F. Gönnenwein; B. Börsig

    1991-01-01

    Cold fission is defined to be the limiting case of nuclear fission where virtually all of the available energy is converted into the total kinetic energy of the fragments. The fragments have, therefore, to be born in or at least close to their respective ground states. Starting from the viewpoint that cold fission corresponds to most compact scission configurations, energy

  8. Neutron absorbers and methods of forming at least a portion of a neutron absorber

    DOEpatents

    Guillen, Donna P; Porter, Douglas L; Swank, W David; Erickson, Arnold W

    2014-12-02

    Methods of forming at least a portion of a neutron absorber include combining a first material and a second material to form a compound, reducing the compound into a plurality of particles, mixing the plurality of particles with a third material, and pressing the mixture of the plurality of particles and the third material. One or more components of neutron absorbers may be formed by such methods. Neutron absorbers may include a composite material including an intermetallic compound comprising hafnium aluminide and a matrix material comprising pure aluminum.

  9. Absorbed fractions for electrons in ellipsoidal volumes

    NASA Astrophysics Data System (ADS)

    Amato, E.; Lizio, D.; Baldari, S.

    2011-01-01

    We applied a Monte Carlo simulation in Geant4 in order to calculate the absorbed fractions for monoenergetic electrons in the energy interval between 10 keV and 2 MeV, uniformly distributed in ellipsoids made from soft tissue. For each volume, we simulated a spherical shape, four oblate and four prolate ellipsoids, and one scalene shape. For each energy and for every geometrical configuration, an analytical relationship between the absorbed fraction and a 'generalized radius' was found, and the dependence of the fit parameters from electron energy is discussed and fitted by proper parametric functions. With the proposed formulation, the absorbed fraction for electrons in the 10-2000 keV energy range can be calculated for all volumes and for every ellipsoidal shape of practical interest. This method can be directly applied to evaluation of the absorbed fraction from the radionuclide emission of monoenergetic electrons, such as Auger or conversion electrons. The average deposited energy per disintegration in the case of extended beta spectra can be evaluated through integration. Two examples of application to a pure beta emitter such as 90Y and to 131I, whose emission include monoenergetic and beta electrons plus gamma photons, are presented. This approach represent a generalization of our previous studies, allowing a comprehensive treatment of absorbed fractions from electron and photon sources uniformly distributed in ellipsoidal volumes of any ellipticity and volume, in the whole range of practical interest for internal dosimetry in nuclear medicine applications, as well as in radiological protection estimations of doses from an internal contamination.

  10. Cold-electron bolometers for future mm and sub-mm sky surveys

    E-print Network

    Salatino, Maria; Mahashabde, Sumedh; Kuzmin, Leonid S; Masi, Silvia

    2014-01-01

    Future sky surveys in the mm/sub-mm range, like the forthcoming balloon-borne missions LSPE, OLIMPO, SPIDER etc., will need detectors insensitive to cosmic rays (CRs) and with a NEP of the order of $10^{-17} \\div 10^{-18}\\,$W/sqrt(Hz). The Cold-Electron Bolometers (CEBs) technology is promising, having the required properties, since the absorber volume is extremely small and the electron system of the absorber is thermally insulated from the phonon system. We have developed an experimental setup to test the optical performance and the CRs insensitivity of CEBs, with the target of integrating them in the OLIMPO and LSPE focal planes.

  11. Cold-electron bolometers for future mm and sub-mm sky surveys

    NASA Astrophysics Data System (ADS)

    Salatino, Maria; de Bernardis, Paolo; Mahashabde, Sumedh; Kuzmin, Leonid S.; Masi, Silvia

    2014-07-01

    Future sky surveys in the mm/sub-mm range, like the forthcoming balloon-borne missions LSPE, OLIMPO, SPIDER etc., will need detectors insensitive to cosmic rays (CRs) and with a NEP of the order of 10-17 ¥ 10-18 W/sqrt(Hz). The Cold-Electron Bolometers (CEBs) technology is promising, having the required proper- ties, since the absorber volume is extremely small and the electron system of the absorber is thermally insulated from the phonon system. We have developed an experimental setup to test the optical performance and the CRs insensitivity of CEBs, with the target of integrating them in the OLIMPO and LSPE focal planes.

  12. Determination of mercury in ash and soil samples by oxygen flask combustion method–Cold vapor atomic fluorescence spectrometry (CVAFS)

    Microsoft Academic Search

    Wenhua Geng; Tsunenori Nakajima; Hirokazu Takanashi; Akira Ohki

    2008-01-01

    A simple method was developed for the determination of mercury (Hg) in coal fly ash (CFA), waste incineration ash (WIA), and soil by use of oxygen flask combustion (OFC) followed by cold vapor atomic fluorescence spectrometry (CVAFS). A KMnO4 solution was used as an absorbent in the OFC method, and the sample containing a combustion agent and an ash or

  13. Absorbing properties and structural design of microwave absorbers based on carbonyl iron and barium ferrite

    Microsoft Academic Search

    Y. B. Feng; T. Qiu; C. Y. Shen

    2007-01-01

    Carbonyl iron and barium ferrite powder (BaZn1.5Co0.5Fe16O27) were prepared in this work. The complex permittivity and permeability spectra for rubber radar absorbing materials employing carbonyl iron and barium ferrite powders were measured. A database describing the frequency dependence of the permittivities and permeabilities of the carbonyl iron and barium ferrite microwave absorbers with various powder percentage compositions in 2–18GHz was

  14. Absorbing properties and structural design of microwave absorbers based on carbonyl iron and barium ferrite

    Microsoft Academic Search

    Y. B. Feng; T. Qiu; C. Y. Shen

    2007-01-01

    Carbonyl iron and barium ferrite powder (BaZn1.5Co0.5Fe16O27) were prepared in this work. The complex permittivity and permeability spectra for rubber radar absorbing materials employing carbonyl iron and barium ferrite powders were measured. A database describing the frequency dependence of the permittivities and permeabilities of the carbonyl iron and barium ferrite microwave absorbers with various powder percentage compositions in 2 18

  15. Cold plasma decontamination of foods.

    PubMed

    Niemira, Brendan A

    2012-01-01

    Cold plasma is a novel nonthermal food processing technology that uses energetic, reactive gases to inactivate contaminating microbes on meats, poultry, fruits, and vegetables. This flexible sanitizing method uses electricity and a carrier gas, such as air, oxygen, nitrogen, or helium; antimicrobial chemical agents are not required. The primary modes of action are due to UV light and reactive chemical products of the cold plasma ionization process. A wide array of cold plasma systems that operate at atmospheric pressures or in low pressure treatment chambers are under development. Reductions of greater than 5 logs can be obtained for pathogens such as Salmonella, Escherichia coli O157:H7, Listeria monocytogenes, and Staphylococcus aureus. Effective treatment times can range from 120 s to as little as 3 s, depending on the food treated and the processing conditions. Key limitations for cold plasma are the relatively early state of technology development, the variety and complexity of the necessary equipment, and the largely unexplored impacts of cold plasma treatment on the sensory and nutritional qualities of treated foods. Also, the antimicrobial modes of action for various cold plasma systems vary depending on the type of cold plasma generated. Optimization and scale up to commercial treatment levels require a more complete understanding of these chemical processes. Nevertheless, this area of technology shows promise and is the subject of active research to enhance efficacy. PMID:22149075

  16. Method of warming cold engines in cold climates

    SciTech Connect

    Forschirm, A.

    1988-12-06

    This patent describes a method of warming cold engines in low temperature conditions comprising the steps of: (a) placing a flammable compound inside a nonflammable fabric bag; (b) placing the bag on an engine; and (c) igniting the flammable compound.

  17. Impedance matched thin metamaterials make metals absorbing

    NASA Astrophysics Data System (ADS)

    Mattiucci, N.; Bloemer, M. J.; Aközbek, N.; D'Aguanno, G.

    2013-11-01

    Metals are generally considered good reflectors over the entire electromagnetic spectrum up to their plasma frequency. Here we demonstrate an approach to tailor their absorbing characteristics based on the effective metamaterial properties of thin, periodic metallo-dielectric multilayers by exploiting a broadband, inherently non-resonant, surface impedance matching mechanism. Based on this mechanism, we design, fabricate and test omnidirectional, thin (<1 micron), polarization independent, extremely efficient absorbers (in principle being capable to reach A > 99%) over a frequency range spanning from the UV to the IR. Our approach opens new venues to design cost effective materials for many applications such as thermo-photovoltaic energy conversion devices, light harvesting for solar cells, flat panel display, infrared detectors, stray light reduction, stealth and others.

  18. Development and application of rotary shock absorber

    SciTech Connect

    Yamamoto, Kozo; Yamada, Toshihiro; Fukuyama, Katsura

    1995-12-31

    In recent years, rear suspension systems with a single shock absorber unit placed behind the engine, have been used primarily in the middle and large classes of motorcycles. Some features such as the longer rear wheel travel, progressive response characteristics and mass concentration at the center part of motorcycle are effective in improving maneuverability of the motorcycle. In the 1980s, the systems were introduced first in the off-road motorcycles and then in the on-road motorcycles. Performance of the systems are excellent, but there are demands for further improvement of suspension characteristics and space utility at the center part of motorcycle. For this purpose, the authors have developed a prototype of a rotary shock absorber and studied the applicability to modern motorcycles.

  19. Shock wave absorber having apertured plate

    DOEpatents

    Shin, Y.W.; Wiedermann, A.H.; Ockert, C.E.

    1983-08-26

    The shock or energy absorber disclosed herein utilizes an apertured plate maintained under the normal level of liquid flowing in a piping system and disposed between the normal liquid flow path and a cavity pressurized with a compressible gas. The degree of openness (or porosity) of the plate is between 0.01 and 0.60. The energy level of a shock wave travelling down the piping system thus is dissipated by some of the liquid being jetted through the apertured plate toward the cavity. The cavity is large compared to the quantity of liquid jetted through the apertured plate, so there is little change in its volume. The porosity of the apertured plate influences the percentage of energy absorbed.

  20. Shock wave absorber having apertured plate

    DOEpatents

    Shin, Yong W. (Western Springs, IL); Wiedermann, Arne H. (Chicago Heights, IL); Ockert, Carl E. (Vienna, VA)

    1985-01-01

    The shock or energy absorber disclosed herein utilizes an apertured plate maintained under the normal level of liquid flowing in a piping system and disposed between the normal liquid flow path and a cavity pressurized with a compressible gas. The degree of openness (or porosity) of the plate is between 0.01 and 0.60. The energy level of a shock wave travelling down the piping system thus is dissipated by some of the liquid being jetted through the apertured plate toward the cavity. The cavity is large compared to the quantity of liquid jetted through the apertured plate, so there is little change in its volume. The porosity of the apertured plate influences the percentage of energy absorbed.

  1. Imaging highly absorbing nanoparticles using photothermal microscopy

    NASA Astrophysics Data System (ADS)

    Lussier, Simon-Alexandre; Moradi, Hamid; Price, Alain; Murugkar, Sangeeta

    2015-03-01

    Gold nanoparticles (NPs) have tremendous potential in biomedicine. They can be used as absorbing labels inside living cells for the purpose of biomedical imaging, biosensing as well as for photothermal therapy. We demonstrate photothermal imaging of highly-absorbing particles using a pump-probe setup. The photothermal signal is recovered by heterodyne detection, where the excitation pump laser is at 532 nm and the probe laser is at 638 nm. The sample is moved by a scanning stage. Proof of concept images of red polystyrene microspheres and gold nanoparticles are obtained with this home-built multimodal microscope. The increase in temperature at the surface of the gold NPs, due to the pump laser beam, can be directly measured by means of this photothermal microscope and then compared with the results from theoretical predictions. This technique will be useful for characterization of nanoparticles of different shapes, sizes and materials that are used in cancer diagnosis and therapy.

  2. Vibration absorber modeling for handheld machine tool

    NASA Astrophysics Data System (ADS)

    Abdullah, Mohd Azman; Mustafa, Mohd Muhyiddin; Jamil, Jazli Firdaus; Salim, Mohd Azli; Ramli, Faiz Redza

    2015-05-01

    Handheld machine tools produce continuous vibration to the users during operation. This vibration causes harmful effects to the health of users for repeated operations in a long period of time. In this paper, a dynamic vibration absorber (DVA) is designed and modeled to reduce the vibration generated by the handheld machine tool. Several designs and models of vibration absorbers with various stiffness properties are simulated, tested and optimized in order to diminish the vibration. Ordinary differential equation is used to derive and formulate the vibration phenomena in the machine tool with and without the DVA. The final transfer function of the DVA is later analyzed using commercial available mathematical software. The DVA with optimum properties of mass and stiffness is developed and applied on the actual handheld machine tool. The performance of the DVA is experimentally tested and validated by the final result of vibration reduction.

  3. Plants in a cold climate.

    PubMed Central

    Smallwood, Maggie; Bowles, Dianna J

    2002-01-01

    Plants are able to survive prolonged exposure to sub-zero temperatures; this ability is enhanced by pre-exposure to low, but above-zero temperatures. This process, known as cold acclimation, is briefly reviewed from the perception of cold, through transduction of the low-temperature signal to functional analysis of cold-induced gene products. The stresses that freezing of apoplastic water imposes on plant cells is considered and what is understood about the mechanisms that plants use to combat those stresses discussed, with particular emphasis on the role of the extracellular matrix. PMID:12171647

  4. Dielectric studies of water absorbed in epoxies 

    E-print Network

    Pham, Ha Quoc

    1987-01-01

    ent) Nay 1987 ABSTRACT Dielectric Studies of Mater Absorbed in Epoxies. (May 1987) Ha I)uoc Pham, B. S. , Tokyo University of Agriculture Chairman of Advisory Committee: C. A. J. Hoeve Epoxy resins are industrially important polymers... of speculation. Since water has a large dipole moment, its mobility and inter- action with polymers can be studied by dielectric spectroscopy as a function of temperature, frequency, and water content, in an alter- nating electric field. Hoeve and co...

  5. Tech Transfer Webinar: Energy Absorbing Materials

    ScienceCinema

    Duoss, Eric

    2014-07-15

    A new material has been designed and manufactured at LLNL that can absorb mechanical energy--a cushion--while also providing protection against sheering. This ordered cellular material is 3D printed using direct ink writing techniques under development at LLNL. It is expected to find utility in application spaces that currently use unordered foams, such as sporting and consumer goods as well as defense and aerospace.

  6. Design and Manufacture of Energy Absorbing Materials

    SciTech Connect

    Duoss, Eric

    2014-05-28

    Learn about an ordered cellular material that has been designed and manufactured using direct ink writing (DIW), a 3-D printing technology being developed at LLNL. The new material is a patterned cellular material that can absorb mechanical energy-a cushion-while also providing protection against sheering. This material is expected to find utility in application spaces that currently use unordered foams, such as sporting and consumer goods as well as defense and aerospace.

  7. BIOCHEMISTRY: An Absorbing Study of Cholesterol

    NSDL National Science Digital Library

    Hooman Allayee (University of California, Los Angeles (UCLA) School of Medicine; Department of Medicine and the Department of Microbiology, Immunology and Molecular Genetics)

    2000-12-01

    Access to the article is free, however registration and sign-in are required. We obtain sterols from the animal and plant food that we eat. How these plant and animal sterols are absorbed, transported around the body, and excreted has been the subject of much investigation. In a Perspective, Allayee and colleagues discuss a new study (Berge et al.) that implicates two new ABC transporter proteins in the efflux of plant and animal sterols from gut epithelial cells into the gut lumen.

  8. Tech Transfer Webinar: Energy Absorbing Materials

    SciTech Connect

    Duoss, Eric

    2014-06-17

    A new material has been designed and manufactured at LLNL that can absorb mechanical energy--a cushion--while also providing protection against sheering. This ordered cellular material is 3D printed using direct ink writing techniques under development at LLNL. It is expected to find utility in application spaces that currently use unordered foams, such as sporting and consumer goods as well as defense and aerospace.

  9. Dielectric studies of water absorbed in epoxies

    E-print Network

    Pham, Ha Quoc

    1987-01-01

    ent) Nay 1987 ABSTRACT Dielectric Studies of Mater Absorbed in Epoxies. (May 1987) Ha I)uoc Pham, B. S. , Tokyo University of Agriculture Chairman of Advisory Committee: C. A. J. Hoeve Epoxy resins are industrially important polymers.... They are used in many applications such as surface coatings, adhesives, elqctronic encapsulation and structural composites. Water absorption in epoxy resins is known to be detrimental to resin performances. One example is the unusually large lowering...

  10. Microwave absorbing properties of high titanium slag

    Microsoft Academic Search

    Li-bo Zhang; Guo Chen; Jin-hui Peng; Jin Chen; Sheng-hui Guo; Xin-hui Duan

    2009-01-01

    Microwave absorbing properties of high titanium slag were investigated by using microwave cavity perturbation technique. High\\u000a titanium slag containing more than 90% TiO2 was prepared by carbothermal reduction of ilmenite. The temperature rise curve of high titanium slag in microwave heating\\u000a process was obtained. Crystalline compounds of high titanium slag before and after microwave irradiation were obtained and\\u000a characterized by

  11. Lightweight Energy Absorbers for Blast Containers

    NASA Technical Reports Server (NTRS)

    Balles, Donald L.; Ingram, Thomas M.; Novak, Howard L.; Schricker, Albert F.

    2003-01-01

    Kinetic-energy-absorbing liners made of aluminum foam have been developed to replace solid lead liners in blast containers on the aft skirt of the solid rocket booster of the space shuttle. The blast containers are used to safely trap the debris from small explosions that are initiated at liftoff to sever frangible nuts on hold-down studs that secure the spacecraft to a mobile launch platform until liftoff.

  12. Design and Manufacture of Energy Absorbing Materials

    ScienceCinema

    Duoss, Eric

    2014-05-30

    Learn about an ordered cellular material that has been designed and manufactured using direct ink writing (DIW), a 3-D printing technology being developed at LLNL. The new material is a patterned cellular material that can absorb mechanical energy-a cushion-while also providing protection against sheering. This material is expected to find utility in application spaces that currently use unordered foams, such as sporting and consumer goods as well as defense and aerospace.

  13. Microwave Studies on Strontium Ferrite Based Absorbers

    Microsoft Academic Search

    A. Verma; R. G. Mendiratta; T. C. Goel; D. C. Dube

    2002-01-01

    Single layer microwave absorbers based on strontium ferrite-epoxy composites have been fabricated and their reflection loss characteristics studied in the X-band (8–12.4 GHz) of microwave frequencies. Permittivity (?r' - j?r?) and permeability (µr' - jµr?) of Co and Ti added strontium ferrite SrCoxTixFe12 - 2xO19 (x = 0.1 to 0.9 in steps of 0.2), have been measured. Thickness of the

  14. Electrochemical cells having hydrogen gas absorbing agent

    Microsoft Academic Search

    F. E. Parsen; T. T. Yatabe

    1982-01-01

    An agent which absorbs hydrogen gas for electrochemical cells is made from an oxide of manganese and nickel, cobalt or iron. At temperatures above about 40°C., the oxide of manganese can be replaced by lead oxide. Hydrophobic binders can be added to the agent or the agent can be microencapsulated in water-impermeable but hydrogen-gas-permeable materials. The agent is preferably added

  15. Development of monofilar rotor hub vibration absorber

    NASA Technical Reports Server (NTRS)

    Duh, J.; Miao, W.

    1983-01-01

    A design and ground test program was conducted to study the performance of the monofilar absorber for vibration reduction on a four-bladed helicopter. A monofilar is a centrifugal tuned two degree-of-freedom rotor hub absorber that provides force attenuation at two frequencies using the same dynamic mass. Linear and non-linear analyses of the coupled monofilar/airframe system were developed to study tuning and attenuation characteristics. Based on the analysis, a design was fabricated and impact bench tests verified the calculated non-rotating natural frequencies and mode shapes. Performance characteristics were measured using a rotating absorber test facility. These tests showed significant attenuation of fixed-system 4P hub motions due to 3P inplane rotating-system hub forces. In addition, detuning effects of the 3P monofilar modal response were small due to the nonlinearities and tuning pin slippage. However, attenuation of 4P hub motions due to 5P inplane hub forces was poor. The performance of the 5P monofilar modal response was degraded by torsional motion of the dynamic mass relative to the support arm which resulted in binding of the dynamic components. Analytical design studies were performed to evaluate this torsional motion problem. An alternative design is proposed which may alleviate the torsional motion of the dynamic mass.

  16. Timing the warm absorber in NGC4051

    NASA Astrophysics Data System (ADS)

    Silva, C.; Uttley, P.; Costantini, E.

    2015-07-01

    In this work we have combined spectral and timing analysis in the characterization of highly ionized outflows in Seyfert galaxies, the so-called warm absorbers. Here, we present our results on the extensive ˜600ks of XMM-Newton archival observations of the bright and highly variable Seyfert 1 galaxy NGC4051, whose spectrum has revealed a complex multi-component wind. Working simultaneously with RGS and PN data, we have performed a detailed analysis using a time-dependent photoionization code in combination with spectral and Fourier timing techniques. This method allows us to study in detail the response of the gas due to variations in the ionizing flux of the central source. As a result, we will show the contribution of the recombining gas to the time delays of the most highly absorbed energy bands relative to the continuum (Silva, Uttley & Costantini in prep.), which is also vital information for interpreting the continuum lags associated with propagation and reverberation effects in the inner emitting regions. Furthermore, we will illustrate how this powerful method can be applied to other sources and warm-absorber configurations, allowing for a wide range of studies.

  17. Cobalt catalyst recovery using heavy olefin absorbent

    SciTech Connect

    Summerlin, W.H.

    1993-08-17

    A method is described for removing cobalt values from the crude product of a cobalt-catalyzed hydroformylation reaction formed from an olefinic feedstock, said crude product containing cobalt compounds in addition to an organic hydroformylation reaction product, which comprises: (a) contacting said crude product with water and an organic acid selected from the group consisting of: formic acid, acetic acid, propionic acid, and acids having a boiling point approximately the same as water; (b) contacting the product of step (a) with a stream of stripping gas to entrain volatile cobalt compounds and light hydrocarbons in said stripping gas, whereby said entrained volatile cobalt compounds are taken out overhead and organic hydroformylation reaction products and water containing water soluble cobaltous salts dissolved therein are taken out as bottoms; (c) separating said water containing water soluble cobaltous salt of step (b) from said organic hydroformylation reaction products; (d) diverting said organic hydroformylation reaction product of step (c) for further downstream treatment by at least one method selected from the group consisting of: hydrogenation and distillation; and (e) contacting said volatile cobalt compounds from step (b) with an olefinic absorbent having a molecular weight greater than said olefinic feedstock, whereby said volatile cobalt compounds are absorbed into said olefinic absorbent, and said stripping gas and said light hydrocarbons are taken overhead as a gaseous product.

  18. Shock wave absorber having a deformable liner

    DOEpatents

    Youngdahl, C.K.; Wiedermann, A.H.; Shin, Y.W.; Kot, C.A.; Ockert, C.E.

    1983-08-26

    This invention discloses a shock wave absorber for a piping system carrying liquid. The absorber has a plastically deformable liner defining the normal flow boundary for an axial segment of the piping system, and a nondeformable housing is spaced outwardly from the liner so as to define a gas-tight space therebetween. The flow capacity of the liner generally corresponds to the flow capacity of the piping system line, but the liner has a noncircular cross section and extends axially of the piping system line a distance between one and twenty times the diameter thereof. Gas pressurizes the gas-tight space equal to the normal liquid pressure in the piping system. The liner has sufficient structural capacity to withstand between one and one-half and two times this normal liquid pressures; but at greater pressures it begins to plastically deform initially with respect to shape to a more circular cross section, and then with respect to material extension by circumferentially stretching the wall of the liner. A high energy shock wave passing through the liner thus plastically deforms the liner radially into the gas space and progressively also as needed in the axial direction of the shock wave to minimize transmission of the shock wave beyond the absorber.

  19. First Year: Clear, cold day

    E-print Network

    Chapman, Michael S.

    First Year: A Gap [I] Clear, cold day Girl sitting on the corner Pile of stained napkins Bright red is invading my brain But Somewhere between the Knowing and Helping There is a gap. By Julia Armendariz, MS1

  20. Gastrointestinal bleeding after cold biopsy.

    PubMed

    Vu, C K; Korman, M G; Bejer, I; Davis, S

    1998-07-01

    Cold biopsy of the gastric mucosa is useful in many gastroduodenal disorders. Antral biopsies are done with increasing frequency to confirm Helicobacter pylori infection and to determine the type and content of gastritis. Gastrointestinal bleeding after gastric cold biopsy is rare. We report two patients who developed melena after cold biopsy of the gastric antrum. Repeat gastroscopies excluded lesions other than the biopsied sites as the source of bleeding. Colonoscopies in both cases did not reveal any evidence of lower GI bleed. Relevant medications include amlodipine, in case 1, and brufen, which was used in case 2 but discontinued before biopsy. Literature review has shown the rarity of clinically significant hemorrhage resulting from gastric cold biopsy. Nevertheless, all patients undergoing gastroscopy should be informed of this potential complication. PMID:9672346

  1. Comparison of piezoelectronic networks acting as distributed vibration absorbers

    E-print Network

    Boyer, Edmond

    Comparison of piezoelectronic networks acting as distributed vibration absorbers Corrado Maurinia, Virginia Polytechnic Institute and State University, Blacksburg VA 24061, USA Abstract Electric vibration absorbers made of distributed piezoelectric devices for the control of beam vibrations are studied

  2. Sinusitis in the common cold

    Microsoft Academic Search

    Tuomo Puhakka; Mika J. Mäkelä; Anu Alanen; Timo Kallio; Leo Korsoff; Pertti Arstila; Maija Leinonen; Markku Pulkkinen; Jouko Suonpää; Jussi Mertsola; Olli Ruuskanen

    1998-01-01

    Background: Acute community-acquired sinusitis is considered a bacterial complication of the common cold. Radiologic abnormalities in sinuses occur, however, in most patients with upper respiratory virus infections.Objective: Assessment of the occurrence, clinical profile, laboratory findings, and outcome of radiologically confirmed sinusitis was carried out as part of a common cold study in young adults.Methods: Clinical examinations and radiography of the

  3. Cold regions hydrology and hydraulics

    SciTech Connect

    Ryan, W.L. (HDR Engineers, Inc., Anchorage, AK (US)); Crissman, R.D. (NY Power Authority, Niagra Falls, NY (US))

    1990-01-01

    This monograph addresses a narrow aspect of cold regions engineering, namely the effects of cold weather on the traditional civil engineering disciplines of hydrology and hydraulics. Hydrologic and hydraulic considerations in the design, construction, and operation of civil works are very important. Many of the problems encountered in the design and construction of buildings, transportation systems, water supply facilities, waste treatment facilities, and hazardous waste disposal facilities, for example are closely tied to the characteristics of the site hydrology.

  4. Antibiotic use for common cold

    Microsoft Academic Search

    Timothy W. Kenealy; Bruce Arroll

    Antibiotics do not help patients with an uncomplicated common cold. Antibiotics can have side effects for the individual taking\\u000a them that range from unpleasant to serious, even lethal. Antibiotic use also contributes to communal harm by encouraging antibiotic\\u000a resistance. If there can be no benefit, but there can be harm, why is the common cold the commonest reason for doctors

  5. Investigation of titanium and polyethylene as UCN absorber materials with AbEx

    NASA Astrophysics Data System (ADS)

    Picker, R.; Altarev, I.; Amos, P.; Franke, B.; Geltenbort, P.; Gutsmiedl, E.; Hartmann, F. J.; Mann, A.; Materne, S.; Müller, A. R.; Paul, S.; Stoepler, R.; Wirth, H.-F.

    2009-12-01

    Marginally trapped neutrons are a major source of systematic errors in storage experiments with ultra-cold neutrons (UCN): their energies slightly exceed the trapping potential and their storage lifetimes are of the same order of magnitude as the neutron ?-decay lifetime to be measured. Hence, they have to be removed before the actual neutron storage period starts. For the magneto-gravitational neutron-lifetime experiment PENeLOPE, a novel absorber scheme was proposed; its efficiency to reduce the systematic influence of marginally trapped UCN on the extracted ?-decay lifetime value had to be investigated. To this end, the cryogenic material-storage experiment AbEx ( Ab sorber Ex periment) was conducted at ILL, Grenoble; neutron-optical properties of storage and absorption materials were investigated. Storage lifetimes shorter than 10 s could be reached for high-energy UCN with the proposed scheme. This translates to a systematic effect on the neutron-lifetime measurement with PENeLOPE of ??n<0.03 s. Polyethylene (PE) and titanium were tested as absorber materials. The temperature dependence of their UCN absorbing efficiency was determined to be rather small and connected not with the upscattering cross-section, but probably with surface contaminations.

  6. Inorganic UV absorbers for the photostabilisation of wood-clearcoating systems: Comparison with organic UV absorbers

    NASA Astrophysics Data System (ADS)

    Aloui, F.; Ahajji, A.; Irmouli, Y.; George, B.; Charrier, B.; Merlin, A.

    2007-02-01

    Inorganic UV absorbers which are widely used today were originally designed neither as a UV blocker in coatings applications, nor for wood protection. In recent years however, there has been extensive interest in these compounds, especially with regard to their properties as a UV blocker in coating applications. In this work, we carried out a comparative study to look into some inorganic and organic UV absorbers used in wood coating applications. The aim of this study is to determine the photostabilisation performances of each type of UV absorbers, to seek possible synergies and the influences of different wood species. We have also searched to find eventual correlation between these performances and the influence of UV absorbers on the film properties. Our study has compared the performances of the following UV absorbers: hombitec RM 300, hombitec RM 400 from the Sachtleben Company; transparent yellow and red iron oxides from Sayerlack as inorganic UV absorbers; organic UV absorbers Tinuvin 1130 and Tinuvin 5151 from Ciba Company. The study was carried out on three wood species: Abies grandis, tauari and European oak. The environmental constraints (in particular the limitation of the emission of volatile organic compounds VOCs) directed our choice towards aqueous formulations marketed by the Sayerlack Arch Coatings Company. The results obtained after 800 h of dry ageing showed that the Tinuvins and the hombitecs present better wood photostabilisations. On the other hand in wet ageing, with the hombitec, there are appearances of some cracks and an increase in the roughness of the surface. This phenomenon is absent when the Tinuvins are used. With regard to these results, the thermomechanical analyses relating to the follow-up of the change of the glass transition temperature ( Tg) of the various coating systems, show a different behaviour between the two types of absorbers. However, contrary to organic UV absorbers, inorganic ones tend to increase Tg during ageing, and, consequently decrease the flexibility of films. These phenomena can lead to the appearance of cracks found in the case of the wet weathering.

  7. Absorbing Boundary Conditions for the Wave Equation and Parallel Computing

    E-print Network

    Halpern, Laurence

    to the truncation boundary which leads to a new way of optimizing absorbing boundary conditions for truncatingAbsorbing Boundary Conditions for the Wave Equation and Parallel Computing Martin J. Gander # Laurence Halpern + March 4, 2005 Abstract Absorbing boundary conditions have been developed for various

  8. An optimal perfectly matched layer with unbounded absorbing function for

    E-print Network

    Rodríguez, Rodolfo

    on the last mentioned technique: local absorbing boundary conditions (ABCs) can be used to preserveAn optimal perfectly matched layer with unbounded absorbing function for time-harmonic acoustic an optimal bounded Perfectly Matched Layer (PML) technique by choosing a particular absorbing function

  9. Absorbing Boundary Conditions for the Wave Equation and Parallel Computing

    E-print Network

    Gander, Martin J.

    boundary which leads to a new way of optimizing absorbing boundary conditions for truncating domains. WeAbsorbing Boundary Conditions for the Wave Equation and Parallel Computing Martin J. Gander # Laurence Halpern + May 8, 2003 Abstract Absorbing boundary conditions have been developed for various types

  10. 14 CFR 27.475 - Tires and shock absorbers.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...2014-01-01 2014-01-01 false Tires and shock absorbers. 27.475 Section 27.475... Ground Loads § 27.475 Tires and shock absorbers. Unless otherwise prescribed...assumed to be in their static position and the shock absorbers to be in their most critical...

  11. 14 CFR 27.475 - Tires and shock absorbers.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...2010-01-01 2010-01-01 false Tires and shock absorbers. 27.475 Section 27.475... Ground Loads § 27.475 Tires and shock absorbers. Unless otherwise prescribed...assumed to be in their static position and the shock absorbers to be in their most critical...

  12. 14 CFR 27.475 - Tires and shock absorbers.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...2011-01-01 2011-01-01 false Tires and shock absorbers. 27.475 Section 27.475... Ground Loads § 27.475 Tires and shock absorbers. Unless otherwise prescribed...assumed to be in their static position and the shock absorbers to be in their most critical...

  13. 14 CFR 29.475 - Tires and shock absorbers.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...2014-01-01 2014-01-01 false Tires and shock absorbers. 29.475 Section 29.475... Ground Loads § 29.475 Tires and shock absorbers. Unless otherwise prescribed...assumed to be in their static position and the shock absorbers to be in their most critical...

  14. 14 CFR 29.475 - Tires and shock absorbers.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...2011-01-01 2011-01-01 false Tires and shock absorbers. 29.475 Section 29.475... Ground Loads § 29.475 Tires and shock absorbers. Unless otherwise prescribed...assumed to be in their static position and the shock absorbers to be in their most critical...

  15. 14 CFR 27.475 - Tires and shock absorbers.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...2013-01-01 2013-01-01 false Tires and shock absorbers. 27.475 Section 27.475... Ground Loads § 27.475 Tires and shock absorbers. Unless otherwise prescribed...assumed to be in their static position and the shock absorbers to be in their most critical...

  16. 14 CFR 27.475 - Tires and shock absorbers.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...2012-01-01 2012-01-01 false Tires and shock absorbers. 27.475 Section 27.475... Ground Loads § 27.475 Tires and shock absorbers. Unless otherwise prescribed...assumed to be in their static position and the shock absorbers to be in their most critical...

  17. 14 CFR 29.475 - Tires and shock absorbers.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...2012-01-01 2012-01-01 false Tires and shock absorbers. 29.475 Section 29.475... Ground Loads § 29.475 Tires and shock absorbers. Unless otherwise prescribed...assumed to be in their static position and the shock absorbers to be in their most critical...

  18. 14 CFR 29.475 - Tires and shock absorbers.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...2010-01-01 2010-01-01 false Tires and shock absorbers. 29.475 Section 29.475... Ground Loads § 29.475 Tires and shock absorbers. Unless otherwise prescribed...assumed to be in their static position and the shock absorbers to be in their most critical...

  19. 14 CFR 29.475 - Tires and shock absorbers.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...2013-01-01 2013-01-01 false Tires and shock absorbers. 29.475 Section 29.475... Ground Loads § 29.475 Tires and shock absorbers. Unless otherwise prescribed...assumed to be in their static position and the shock absorbers to be in their most critical...

  20. Modified Berenger PML absorbing boundary condition for FDTD meshes

    Microsoft Academic Search

    B. Chen; D. G. Fang; B. H. Zhou

    1995-01-01

    A new modified, perfectly matched layer absorbing boundary condition (MPML ABC) is presented. In the MPML, the introducing of extra degrees of freedom provides the possibility of adjusting the parameters of nonphysical material absorber (PML) for the purpose of enhancing the attenuation rate of the evanescent modes. Compared to Berenger PML, the MPML is more efficient in absorbing the evanescent

  1. Quantitative Photo-Acoustic Imaging of Small Absorbers Habib Ammari

    E-print Network

    Kang, Hyeonbae

    Quantitative Photo-Acoustic Imaging of Small Absorbers Habib Ammari Emmanuel Bossy Vincent Jugnon Hyeonbae Kang§ December 1, 2009 Abstract In photo-acoustic imaging, energy absorption causes thermo absorber from the absorbed density. AMS subject classifications. 31B20, 35B37,35L05 Key words. photo

  2. Notes 10. The dynamic vibration absorber 

    E-print Network

    San Andres, Luis

    2008-01-01

    ? cos ? t? ?+ () ?= [4] Thus, the periodic force response of the system (Kp,Mp) is : [3] as the frequency ratior ? ? np =with: Z p r() F o K p 1 r 2 ? () := or Zp F o K p ? 2 M p ??() = K p ? 2 M p ??()Zp? F o = Substitution of [2] into [1] gives: [2...] Luis San Andres (c) 2008 MEEN 363 - 617 THE VIBRATION ABSORBER Preamble - A NEED arises: Consider the periodic forced response of a primary system (Kp-Mp) defined by X p (t) K p F(t) M P M p 10 3 lb?:= K p 110 5 ? lbf in ?:= Its natural frequency is...

  3. Absorbing photonic crystals for thin film photovoltaics

    NASA Astrophysics Data System (ADS)

    El Daif, O.; Drouard, E.; Gomard, G.; Meng, X.; Kaminski, A.; Fave, A.; Lemiti, M.; Garcia Cavrel, E.; Roca i Cabarrocas, P.; Ahn, S.; Jeon, H.; Seassal, C.

    2010-05-01

    The absorption of thin hydrogenated amorphous silicon layers can be efficiently enhanced through a controlled periodic patterning. Light is trapped through coupling with photonic Bloch modes of the periodic structures, which act as an absorbing planar photonic crystal. We theoretically demonstrate this absorption enhancement through one or two dimensional patterning, and show the experimental feasibility through large area holographic patterning. Numerical simulations show over 50% absorption enhancement over the part of the solar spectrum comprised between 380 and 750nm. It is experimentally confirmed by optical measurements performed on planar photonic crystals fabricated by laser holography and reactive ion etching.

  4. Absorbing photonic crystals for thin film photovoltaics

    E-print Network

    Daif, O El; Gomard, G; Meng, X; Kaminski, A; Fave, A; Lemiti, M; Caurel, E Garcia; Cabarrocas, P Roca i; Ahn, S; Jeon, H; Seassal, C; 10.1117/12.854035

    2010-01-01

    The absorption of thin hydrogenated amorphous silicon layers can be efficiently enhanced through a controlled periodic patterning. Light is trapped through coupling with photonic Bloch modes of the periodic structures, which act as an absorbing planar photonic crystal. We theoretically demonstrate this absorption enhancement through one or two dimensional patterning, and show the experimental feasibility through large area holographic patterning. Numerical simulations show over 50% absorption enhancement over the part of the solar spectrum comprised between 380 and 750nm. It is experimentally confirmed by optical measurements performed on planar photonic crystals fabricated by laser holography and reactive ion etching.

  5. Heat Transfer Performance of Absorber of Absorption Refrigerating Machine

    NASA Astrophysics Data System (ADS)

    Kunugi, Yoshifumi; Ouchi, Tomihisa; Usui, Sanpei; Fukuda, Tamio

    Experimental studies on heat transfer performance of absorber for lithium bromide-water absorption refrigerating machine are presented in this paper. Experimental apparatus for 35 kW evaporator and absorber, and outer grooved tubes are used. As a result, over-al1 coefficient of heat transmission of absorber has a maximum value, in the case of heat transfer area ratio of absorber to evaporator, is about 0.8. Heat transfer rate of absorber is increased by 60% by using the outer grooved tube compared with the plane surfaced tube.

  6. Determination of decay coefficients for combustors with acoustic absorbers

    NASA Technical Reports Server (NTRS)

    Mitchell, C. E.; Espander, W. R.; Baer, M. R.

    1972-01-01

    An analytical technique for the calculation of linear decay coefficients in combustors with acoustic absorbers is presented. Tuned circumferential slot acoustic absorbers were designed for the first three transverse modes of oscillation, and decay coefficients for these absorbers were found as a function of backing distance for seven different chamber configurations. The effectiveness of the absorbers for off-design values of the combustion response and acoustic mode is also investigated. Results indicate that for tuned absorbers the decay coefficient increases approximately as the cube of the backing distance. For most off-design situations the absorber still provides a damping effect. However, if an absorber designed for some higher mode of oscillation is used to damp lower mode oscillations, a driving effect is frequently found.

  7. Erbium concentration dependent absorbance in tellurite glass

    SciTech Connect

    Sazali, E. S., E-mail: mdsupar@utm; Rohani, M. S., E-mail: mdsupar@utm; Sahar, M. R., E-mail: mdsupar@utm; Arifin, R., E-mail: mdsupar@utm; Ghoshal, S. K., E-mail: mdsupar@utm; Hamzah, K., E-mail: mdsupar@utm [Advanced Optical Material Research Group, Department of Physics, Faculty of Science, Universiti Teknologi Malaysia, 81310, Skudai, Johor Bahru, Johor (Malaysia)

    2014-09-25

    Enhancing the optical absorption cross-section in topically important rare earth doped tellurite glasses is challenging for photonic devices. Controlled synthesis and detailed characterizations of the optical properties of these glasses are important for the optimization. The influence of varying concentration of Er{sup 3+} ions on the absorbance characteristics of lead tellurite glasses synthesized via melt-quenching technique are investigated. The UV-Vis absorption spectra exhibits six prominent peaks centered at 490, 526, 652, 800, 982 and 1520 nm ascribed to the transitions in erbium ion from the ground state to the excited states {sup 4}F{sub 7/2}, {sup 2}H{sub 11/2}, {sup 4}F{sub 9/2}, {sup 4}I{sub 9/2}, {sup 2}H{sub 11/2} and {sup 4}I{sub 13/2}, respectively. The results are analyzed by means of optical band gap E{sub g} and Urbach energy E{sub u}. The values of the energy band gap are found decreased from 2.82 to 2.51 eV and the Urbach energy increased from 0.15 to 0.24 eV with the increase of the Er{sub 2}O{sub 3} concentration from 0 to 1.5 mol%. The excellent absorbance of the prepared tellurite glasses makes them suitable for fabricating solid state lasers.

  8. Multiple-Path-Length Optical Absorbance Cell

    NASA Technical Reports Server (NTRS)

    2001-01-01

    An optical absorbance cell that offers a selection of multiple optical path lengths has been developed as part of a portable spectrometric instrument that measures absorption spectra of small samples of water and that costs less than does a conventional, non-portable laboratory spectrometer. The instrument is intended, more specifically, for use in studying colored dissolved organic matter (CDOM) in seawater, especially in coastal regions. Accurate characterization of CDOM is necessary for building bio-optical mathematical models of seawater. The multiple path lengths of the absorption cell afford a wide range of sensitivity needed for measuring the optical absorbances associated with the wide range of concentrations of CDOM observed in nature. The instrument operates in the wavelength range of 370 to 725 nm. The major subsystems of the instrument (see figure) include a color-balanced light source; the absorption cell; a peristaltic pump; a high-precision, low-noise fiber optic spectrometer; and a laptop or other personal computer. A fiber-optic cable transmits light from the source to the absorption cell. Other optical fibers transmit light from the absorption cell to the spectrometer,

  9. Wave energy extraction by coupled resonant absorbers.

    PubMed

    Evans, D V; Porter, R

    2012-01-28

    In this article, a range of problems and theories will be introduced that will build towards a new wave energy converter (WEC) concept, with the acronym 'ROTA' standing for resonant over-topping absorber. First, classical results for wave power absorption for WECs constrained to operate in a single degree of freedom will be reviewed and the role of resonance in their operation highlighted. Emphasis will then be placed on how the introduction of further resonances can improve power take-off characteristics by extending the range of frequencies over which the efficiency is close to a theoretical maximum. Methods for doing this in different types of WECs will be demonstrated. Coupled resonant absorbers achieve this by connecting a WEC device equipped with its own resonance (determined from a hydrodynamic analysis) to a new system having separate mass/spring/damper characteristics. It is shown that a coupled resonant effect can be realized by inserting a water tank into a WEC, and this idea forms the basis of the ROTA device. In essence, the idea is to exploit the coupling between the natural sloshing frequencies of the water in the internal tank and the natural resonance of a submerged buoyant circular cylinder device that is tethered to the sea floor, allowing a rotary motion about its axis of attachment. PMID:22184664

  10. Is It a Cold or an Allergy? Symptoms Cold Airborne Allergy

    E-print Network

    Bandettini, Peter A.

    Is It a Cold or an Allergy? Symptoms Cold Airborne Allergy Cough Common Sometimes General Aches Decongestants Prevention Wash your hands often with soap and water Avoid close contact with anyone with a cold

  11. COLD-SAT dynamic model

    NASA Technical Reports Server (NTRS)

    Adams, Neil S.; Bollenbacher, Gary

    1992-01-01

    This report discusses the development and underlying mathematics of a rigid-body computer model of a proposed cryogenic on-orbit liquid depot storage, acquisition, and transfer spacecraft (COLD-SAT). This model, referred to in this report as the COLD-SAT dynamic model, consists of both a trajectory model and an attitudinal model. All disturbance forces and torques expected to be significant for the actual COLD-SAT spacecraft are modeled to the required degree of accuracy. Control and experimental thrusters are modeled, as well as fluid slosh. The model also computes microgravity disturbance accelerations at any specified point in the spacecraft. The model was developed by using the Boeing EASY5 dynamic analysis package and will run on Apollo, Cray, and other computing platforms.

  12. Strength function under the absorbing boundary condition

    NASA Astrophysics Data System (ADS)

    Iwasaki, M.; Otani, R.; Ito, M.

    2014-12-01

    The strength function of the linear response by the external field is calculated in the formalism of the absorbing boundary condition (ABC). The dipole excitation of a schematic two-body system is treated in the present study. The extended completeness relation, which is assumed on the analogy of the formulation in the complex scaling method (CSM), is applied to the calculation of the strength function. The calculation of the strength function is successful in the present formalism and hence, the extended completeness relation seems to work well in the ABC formalism. The contributions from the resonance and the non-resonant continuum is also analyzed according to the decomposition of the energy levels in the extended completeness relation.

  13. Porous Carbon Nanoparticle Networks with Tunable Absorbability

    PubMed Central

    Dai, Wei; Kim, Seong Jin; Seong, Won-Kyeong; Kim, Sang Hoon; Lee, Kwang-Ryeol; Kim, Ho-Young; Moon, Myoung-Woon

    2013-01-01

    Porous carbon materials with high specific surface areas and superhydrophobicity have attracted much research interest due to their potential application in the areas of water filtration, water/oil separation, and oil-spill cleanup. Most reported superhydrophobic porous carbon materials are fabricated by complex processes involving the use of catalysts and high temperatures but with low throughput. Here, we present a facile single-step method for fabricating porous carbon nanoparticle (CNP) networks with selective absorbability for water and oils via the glow discharge of hydrocarbon plasma without a catalyst at room temperature. Porous CNP networks were grown by the continuous deposition of CNPs at a relatively high deposition pressure. By varying the fluorine content, the porous CNP networks exhibited tunable repellence against liquids with various degrees of surface tension. These porous CNP networks could be applied for the separation of not only water/oil mixtures but also mixtures of liquids with different surface tension levels. PMID:23982181

  14. Skin interaction with absorbent hygiene products.

    PubMed

    Runeman, Bo

    2008-01-01

    Skin problems due to the use of absorbent hygiene products, such as diapers, incontinence pads, and feminine sanitary articles, are mostly due to climate or chafing discomfort. If these conditions are allowed to prevail, these may develop into an irritant contact dermatitis and eventually superficial skin infections. Skin humidity and aging skin are among the most significant predisposing and aggravating factors for dermatitis development. Improved product design features are believed to explain the decline in observed diaper dermatitis among infants. Where adult incontinence-related skin problems are concerned, it is very important to apply a holistic perspective to understand the influences due to the individual's incontinence level and skin condition, as well as the hygiene and skin care measures provided. Individuals with frail, sensitive skin or with skin diseases may preferably have to use high-quality products, equipped with superabsorbent polymers and water vapor-permeable back sheets, to minimize the risk of skin complications. PMID:18280904

  15. A High-Resolution Survey of Low-Redshift QSO Absorption Lines: Statistics and Physical Conditions of O VI Absorbers

    E-print Network

    Todd M. Tripp; Kenneth R. Sembach; David V. Bowen; Blair D. Savage; Edward B. Jenkins; Nicolas Lehner; Philipp Richter; ;

    2008-02-19

    Using high-resolution UV spectra of 16 low-z QSOs, we study the physical conditions and statistics of O VI absorption in the IGM at z 30 mA, the number of O VI absorbers per unit redshift dN/dz = 15.6(+2.9/-2.4) [21.0(+3.2/-2.8)], and this decreases to dN/dz = 0.9(+1.0/-0.5) [0.3(+0.7/-0.3)] for W_{r} > 300 mA. The number per redshift increases steeply as z_{abs} approaches z_{QSO}, and some proximate absorbers have substantially lower H I/O VI ratios. The lower proximate ratios could be partially due to ionization effects but also require higher metallicities. We find that 37% of the intervening O VI absorbers have velocity centroids that are well-aligned with corresponding H I absorption. If the O VI and the H I trace the same gas, the relatively small differences in line widths imply the absorbers are cool with T 10^{5} K and cold photoionzed gas.

  16. The status of `cold fusion'

    Microsoft Academic Search

    David J. Nagel

    1998-01-01

    The questions raised by reports of nuclear reactions at low energies, so called `cold fusion', are not yet answered to the satisfaction of many scientists. Further experimental investigations of these and related questions seems desirable, at least for scientific if not practical reasons. Properly conducted, such investigations would be indistinguishable from normal research. They would yield information germane to accepted

  17. Bad cold for a butterfly?

    Microsoft Academic Search

    Wilte G. Zijlstra; Bas J. Zwaan; Paul M. Brakefield

    The tropical butterfly Bicyclus anynana can, in the dry season, encounter temperatures below 10°C or even lower at higher altitudes. We studied the cold resistance of several stages in the life cycle of this butterfly (egg, pupa, adult). Egg hatching declined at low temperatures, with no hatching at +6°C and reduced hatching at 12°C. Pupa could sustain almost two days

  18. Cold War Geopolitics: Embassy Locations.

    ERIC Educational Resources Information Center

    Vogeler, Ingolf

    1995-01-01

    Asserts that the geopolitics of the Cold War can be illustrated by the diplomatic ties among countries, particularly the superpowers and their respective allies. Describes a classroom project in which global patterns of embassy locations are examined and compared. Includes five maps and a chart indicating types of embassy locations. (CFR)

  19. Underwater cold tap machine tested

    SciTech Connect

    Not Available

    1985-05-01

    Tests are complete on a strategic cold tap machine for underwater lines. The system was designed around Total's Norway-UK Frigg gas line. It provides a permanent, easily mobilized, mechanical insurance against damage to the Frigg line but also provides a proven, workable principle for the repair or modification of other lines. The design of the system is discussed.

  20. The Cold Blooded Killer: Hypothermia.

    ERIC Educational Resources Information Center

    Keller, Rosanne

    Part of a series of home literacy readers with conversational text and sketches, this booklet depicts the subarctic Alaskan environment where cold makes extreme demands on body metabolism. Body temperature must be maintained above 80F (26.7C). A condition of too little body-heat is termed hypo- ('deficit') thermia ('heat'). Hypothermia is the…

  1. Advances in cold plasma technology

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Foodborne pathogens continue to be an issue on a variety of commodities, prompting research into novel interventions. Cold plasma is a nonthermal food processing technology which uses energetic, reactive gases to inactivate contaminating microbes on meats, poultry and fruits and vegetables. The prim...

  2. Interface Model of Cold Fusion

    Microsoft Academic Search

    Talbot A. Chubb

    The interface theory of cold fusion is a variant of Ion Band State (IBS) Theory.1 It models Bloch symmetry deuterons in a 2-dimensional metal lattice instead of the 3-dimensional metal lattice first used. Both IBS variants recognize that the required lattice symmetry has limited extent, with the reactive deuterons being bound inside a closed volume like a box. The reactive

  3. Hot, Cold, Fresh and Salty

    NSDL National Science Digital Library

    Jerry Roth

    In this activity, learners observe the effects of the layering of warm and cold water and water that is more or less saline than regular water. They will discover how the effects of salinity and temperature are the root cause of thermohaline layering in the ocean.

  4. An acoustic absorber implemented by graded index phononic crystals

    NASA Astrophysics Data System (ADS)

    Liang, Yu-Jui; Chen, Lien-Wen; Wang, Ching-Cheng; Chang, I.-Ling

    2014-06-01

    In this paper, we proposed the implementation of a two-dimensional omnidirectional and broadband acoustic absorber using graded index phononic crystals as the shell with an inner absorbing core. The phononic crystal was consisted of circular steel rod arranged as square lattice in air background. The plane wave expansion method was used to obtain the band diagram of the phononic crystal from which the effective refractive index could be computed. The radially distributed refractive index of the acoustic absorber was achieved by placing steel rods with spatially varying radii. The finite element method was employed in order to confirm the acoustic properties of the designed device. Numerical simulations illustrated that the acoustic waves were bent toward the central area by the outer shell and absorbed by the inner core of the implemented acoustic absorber. Furthermore, it was demonstrated that the implemented acoustic absorber could operate independent of the incident wave directions for a relative wide range of frequencies.

  5. Two-Photon Cooperative Absorption in Colliding Cold Na Atoms

    NASA Astrophysics Data System (ADS)

    Pedrozo-Peñafiel, E.; Paiva, R. R.; Vivanco, F. J.; Bagnato, V. S.; Farias, K. M.

    2012-06-01

    Two-photon cooperative absorption is common in solid-state physics. In a sample of trapped cold atoms, this effect may open up new possibilities for the study of nonlinear effects. The experiment described herein starts with two colliding Na atoms in the S hyperfine ground state. The pair absorb two photons, resulting in both a P1/2 and a P3/2 atom. This excitation is observed by ionization using an external light source. A simple model that considers only dipole-dipole interactions between the atoms allows us to understand the basic features observed in the experimental results. Both the pair of generated atoms and the photons originating from their decay are correlated and may have interesting applications that remain to be explored.

  6. Infrared perfect absorber and its application as plasmonic sensor.

    PubMed

    Liu, Na; Mesch, Martin; Weiss, Thomas; Hentschel, Mario; Giessen, Harald

    2010-07-14

    We experimentally demonstrate a perfect plasmonic absorber at lambda = 1.6 microm. Its polarization-independent absorbance is 99% at normal incidence and remains very high over a wide angular range of incidence around +/-80 degrees. We introduce a novel concept to utilize this perfect absorber as plasmonic sensor for refractive index sensing. This sensing strategy offers great potential to maintain the performance of localized surface plasmon sensors even in nonlaboratory environments due to its simple and robust measurement scheme. PMID:20560590

  7. Reflectivity of commercial absorbers at 100-200 GHz

    Microsoft Academic Search

    A. Lehto; J. Tuovinen; A. Raisanen

    1991-01-01

    Different types (pyramidal, convoluted, wedge, flat) of absorber panels made by three manufacturers have been measured at 107 and 183 GHz. These measurements revealed a rapid degradation of the quality of absorbers from 107 to 183 GHz: reflectivity increased nearly 10 dB. The best absorbers have reflectivities below -40 dB at 107 GHz and about -35 dB at 183 GHz.

  8. Reflectivity of absorbers in 100-200 GHz range

    Microsoft Academic Search

    A. Lehto; J. Tuovinen; A. Raisanen

    1991-01-01

    Different types (pyramidal, convoluted, wedge, flat) of absorber panel made by several manufacturers have been measured at 107 and 183 GHz. These measurements revealed a rapid degradation of the quality of absorbers from 107 to 183 GHz: reflectivity increased nearly 10 dB. The best absorbers have reflectivities below -40 dB at 107 GHz and about -35 dB at 183 GHz.

  9. Study on mechanical properties of high-temperature absorbing coats

    Microsoft Academic Search

    Dongmei Zhu; Fa Luo; Liangming Xiong; Wancheng Zhou

    2007-01-01

    SiCN nano-powder, a good high-temperature absorber, was introduced as the absorber into the BaO–La2O3–B2O3 glass to prepare the high-temperature absorbing coats on the Ti-based alloy substrates. The difference of thermal expansion coefficient between the glass and Ti-alloy was determined through thermal mechanical analysis (TMA) and the wet ability of the glass to the substrate was explored. The mechanical properties including

  10. Vertical-plane pendulum absorbers for minimizing helicopter vibratory loads

    NASA Technical Reports Server (NTRS)

    Amer, K. B.; Neff, J. R.

    1974-01-01

    The use of pendulum dynamic absorbers mounted on the blade root and operating in the vertical plane to minimize helicopter vibratory loads was discussed. A qualitative description was given of the concept of the dynamic absorbers and some results of analytical studies showing the degree of reduction in vibratory loads attainable are presented. Operational experience of vertical plane dynamic absorbers on the OH-6A helicopter is also discussed.

  11. Selection of new absorbents for carbon dioxide capture

    Microsoft Academic Search

    Sholeh Ma’mun; Hallvard F. Svendsen; Karl A. Hoff; Olav Juliussen

    2007-01-01

    This work focuses on selecting new absorbents for CO2 capture. Absorption of CO2 was studied at 40°C using both single and mixed amine-based absorbents. The experimental results show that most absorbents tested have a poorer performance than MEA, but that aqueous AEEA might be a possible contender. In addition to the absorption measurements, the VLE of CO2 in the selected

  12. Tips to Protect Workers in Cold Environments

    MedlinePLUS

    Tips To Protect Workers In Cold Environments Prolonged exposure to freezing or cold temperatures may cause serious health problems such as trench foot, frostbite and hypothermia. In extreme cases, ...

  13. Helium Find Thaws the Cold Fusion Trail.

    ERIC Educational Resources Information Center

    Pennisi, E.

    1991-01-01

    Reported is a study of cold fusion in which trace amounts of helium, possible evidence of an actual fusion reaction, were found. Research methodology is detailed. The controversy over the validity of experimental results with cold fusion are reviewed. (CW)

  14. Understanding Colds: Anatomy of the Nose

    MedlinePLUS

    ... 5) New virus particles are produced in the infected cell. The infected cell eventually dies and ruptures, releasing newly made cold ... body's response to the infection. When a nasal cell is infected by a cold virus, the body responds by ...

  15. 75 FR 52213 - Cold Treatment Regulations

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-25

    ...integrity of cold treatment temperature data rather...effectiveness of cold treatment and prevent the introduction...Inder P. S. Gadh, Senior Risk Manager-Treatments, Regulations, Permits...certifying or approving treatment facilities and...

  16. Coughs and Colds: Medicines or Home Remedies?

    MedlinePLUS

    ... Issues Listen Español Text Size Email Print Share Coughs and Colds: Medicines or Home Remedies? Article Body Medicines Over-the-counter (OTC) cough and cold medicines can cause serious side effects ...

  17. 21 CFR 890.5700 - Cold pack.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices § 890.5700 Cold pack. (a) Identification. A cold pack is a...

  18. 21 CFR 890.5700 - Cold pack.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices § 890.5700 Cold pack. (a) Identification. A cold pack...

  19. 21 CFR 890.5700 - Cold pack.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices § 890.5700 Cold pack. (a) Identification. A cold pack...

  20. 21 CFR 890.5700 - Cold pack.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices § 890.5700 Cold pack. (a) Identification. A cold pack...

  1. Phase Structure of Weak MgII Absorbers: Star Forming Pockets Outside of Galaxies

    E-print Network

    Jane C. Charlton; Christopher W. Churchill; Jie Ding; Stephanie Zonak; Nicholas Bond; Jane R. Rigby

    2001-10-14

    A new and mysterious class of object has been revealed by the detection of numerous weak MgII doublets in quasar absorption line spectra. The properties of these objects will be reviewed. They are not in close proximity to luminous galaxies, yet they have metallicities close to the solar value; they are likely to be self-enriched. A significant fraction of the weak MgII absorbers are constrained to be less than 10 parsecs in size, yet they present a large cross-section for absorption, indicating that there are more than a million times more of them than there are luminous galaxies. They could be remnants of Population III star clusters or tracers of supernova remnants in a population of "failed dwarf galaxies" expected in cold dark matter structure formation scenarios.

  2. The cold equation of state of tantalum

    SciTech Connect

    Greeff, Carl W [Los Alamos National Laboratory; Rudin, Sven P [Los Alamos National Laboratory; Corckett, Scott D [Los Alamos National Laboratory; Wills, John M [Los Alamos National Laboratory

    2009-01-01

    In high-pressure isentropic compression experiments (ICE), the pressure is dominated by the cold curve. In order to obtain an accurate semi-empirical cold curve for Ta, we calculate the thermal pressure from ab initio phonon and electronic excitation spectra. The cold curve is then inferred from ultrasonic and shock data. Our empirical cold pressure is compared to density functional calculations and found to be closer to GGA results at low pressure and to approach LDA at high pressure.

  3. Cold paresis in multifocal motor neuropathy

    Microsoft Academic Search

    Dirk C. G. Straver; Jan-Thies H. van Asseldonk; Nicolette C. Notermans; John H. J. Wokke; Leonard H. van den Berg; Hessel Franssen

    2011-01-01

    Increased weakness during cold (cold paresis) was reported in single cases of multifocal motor neuropathy (MMN). This was\\u000a unexpected because demyelination is a feature of MMN and symptoms of demyelination improve, rather than worsen, in cold. It\\u000a was hypothesized that cold paresis in MMN does not reflect demyelination only, but may indicate the existence of inflammatory\\u000a nerve lesions with permanently

  4. Cold moderators for pulsed neutron sources

    SciTech Connect

    Carpenter, J.M.

    1990-01-01

    This paper reviews cold moderators in pulsed neutron sources and provides details of the performance of different cold moderator materials and configurations. Analytical forms are presented which describe wavelength spectra and emission time distributions. Several types of cooling arrangements used in pulsed source moderators are described. Choices of materials are surveyed. The author examines some of the radiation damage effects in cold moderators, including the phenomenon of burping'' in irradiated cold solid methane. 9 refs., 15 figs., 4 tabs.

  5. Genetic control of plant resistance to cold

    Microsoft Academic Search

    A. S. Kurbidaeva; M. G. Novokreshchenova

    2011-01-01

    Data on the main pathways of the effect of cold on plants and on the pathways of plant responses to cold stress are reviewed.\\u000a Genes involved in these processes are described. Special attention is given to transcription factors regulating expression\\u000a of cold resistance genes. In addition, the participation of hormones and metabolites in the protection of plants from cold-induced\\u000a damage

  6. Vitamin C and the common cold

    Microsoft Academic Search

    Harri Hemilä

    1992-01-01

    The effect of vitamin C on the common cold has been the subject of several studies. These studies do not support a considerable decrease in the incidence of the common cold with supplemental vitamin C. However, vitamin C has consistently decreased the duration of cold episodes and the severity of symptoms. The benefits that have been observed in different studies

  7. Vernalizing cold is registered digitally at FLC

    PubMed Central

    Angel, Andrew; Song, Jie; Yang, Hongchun; Questa, Julia I.; Dean, Caroline; Howard, Martin

    2015-01-01

    A fundamental property of many organisms is an ability to sense, evaluate, and respond to environmental signals. In some situations, generation of an appropriate response requires long-term information storage. A classic example is vernalization, where plants quantitatively sense long-term cold and epigenetically store this cold-exposure information to regulate flowering time. In Arabidopsis thaliana, stable epigenetic memory of cold is digital: following long-term cold exposure, cells respond autonomously in an all-or-nothing fashion, with the fraction of cells that stably silence the floral repressor FLOWERING LOCUS C (FLC) increasing with the cold exposure duration. However, during cold exposure itself it is unknown whether vernalizing cold is registered at FLC in individual cells in an all-or-nothing (digital) manner or is continuously varying (analog). Using mathematical modeling, we found that analog registration of cold temperature is problematic due to impaired analog-to-digital conversion into stable memory. This disadvantage is particularly acute when responding to short cold periods, but is absent when cold temperatures are registered digitally at FLC. We tested this prediction experimentally, exposing plants to short periods of cold interrupted with even shorter warm breaks. For FLC expression, we found that the system responds similarly to both interrupted and uninterrupted cold, arguing for a digital mechanism integrating long-term temperature exposure. PMID:25775579

  8. Indian cold chain: modeling the inhibitors

    Microsoft Academic Search

    Rohit Joshi; Devinder Kumar Banwet; Ravi Shankar

    2009-01-01

    Purpose – The cold chain has become an integral part of the supply chain of perishable items. Recent studies have shown a critical absence of a strong and dependable cold chain in developing economies. The purpose of this paper is to set out to identify and inter-relate the inhibitors that significantly influence the efficiency of a cold chain in developing

  9. The Dok Cold Eddy D. A. MITCHELL*

    E-print Network

    Rhode Island, University of

    The Dok Cold Eddy D. A. MITCHELL* Graduate School of Oceanography, University of Rhode Island June 1999 and July 2001. The focus here is the formation and behavior of a persistent cold eddy observed south of Dok Island, referred to as the Dok Cold Eddy (DCE), and meandering of the Subpolar Front

  10. Cold Chain Equipment Planning with CCEM

    E-print Network

    Anderson, Richard

    1/24/2011 1 Cold Chain Equipment Planning with CCEM Richard Anderson, Sophie Newland, John Lloyd, David Lubinski, Stefano Malvolti, John Wecker, Kate Wilson Cold Chain Equipment Planning with CCEM January 4, 2011 Vaccine Introduction Timeline Cold Chain Equipment Manager 2 IVAC VIMS report, March 2010

  11. Cold Shock Expression System pCold TF DNA 1TAKARA BIO INC.

    E-print Network

    Lebendiker, Mario

    Cold Shock Expression System pCold TF DNA 1TAKARA BIO INC. v.050630 Cat.# 3365 URL Shock Expression System pCold TF DNA v.050630 Cat.# 3365 URL:http://www.takara-bio.com Elucidation protein yield, purity, and solubility for ex- pressed recombinant proteins using "cold shock" technology

  12. Cold Fusion Has Now Come Out of the Cold

    Microsoft Academic Search

    Edmund Storms

    2003-01-01

    The phenomenon called cold fusion or LENR (Low-Energy-Nuclear-Reaction) has now achieved a level of reproducibility and understanding that warrants re-examination of the claims. A summary of what is known and want is being done worldwide to obtain more knowledge will be given. Rather than disappearing as better data are obtained, the effects are becoming more reproducible and of greater magnitude.

  13. Absorbed dose measurements and predictions on LDEF

    NASA Technical Reports Server (NTRS)

    Frank, A. L.; Benton, E. V.; Armstrong, T. W.; Colborn, B. L.

    1993-01-01

    The overall radiation environment of the Long Duration Exposure Facility (LDEF) was determined in part through the use of thermoluminescent detectors (TLD's) which were included in several experiments. The results given are from four experiments (A0015 Biostack, M0004 Fiber Optics Data Link, P0004 Seeds in Space, and P0006 Linear Energy Transfer Spectrum Measurement) and represent a large fraction of existing absorbed dose data. The TLD's were located on the leading and the trailing edges and the Earth end of the spacecraft under various shielding depths (0.48 to 15.4 g/sq cm). The measured absorbed doses were found to reflect both directional dependence of incident trapped protons and shielding. At the leading edge, doses ranged from 2.10 to 2.58 Gy under shielding of 2.90 to 1.37 g/sq cm Al equivalent (M0004). At the trailing edge, doses varied from 3.04 to 4.49 Gy under shielding of 11.7 to 3.85 g/sq cm (A0015), doses varied from 2.91 to 6.64 Gy under shielding of 11.1 to 0.48 g/sq cm (P0004), and a dose range of 2.66 to 6.48 Gy was measured under shielding of 15.4 to 0.48 g/sq cm (P0006). At the Earth end of the spacecraft, doses from 2.41 to 3.93 Gy were found under shielding of 10.0 to 1.66 g/sq cm (A0015). The effect of the trapped proton anisotropy was such that the western side of LDEF received more than 2 times the dose of the eastern side at shielding depths of approximately 1 g/sq cm. Calculations utilizing a directional model of trapped proton spectra predict smaller doses than those measured, being about 50 percent of measured values at the trailing edge and Earth end, and about 80 percent near the leading edge.

  14. Global transcriptional profiling of a cold-tolerant rice variety under moderate cold stress reveals different cold stress response mechanisms.

    PubMed

    Zhao, Junliang; Zhang, Shaohong; Yang, Tifeng; Zeng, Zichong; Huang, Zhanghui; Liu, Qing; Wang, Xiaofei; Leach, Jan; Leung, Hei; Liu, Bin

    2015-07-01

    Gene expression profiling under severe cold stress (4°C) has been conducted in plants including rice. However, rice seedlings are frequently exposed to milder cold stresses under natural environments. To understand the responses of rice to milder cold stress, a moderately low temperature (8°C) was used for cold treatment prior to genome-wide profiling of gene expression in a cold-tolerant japonica variety, Lijiangxintuanheigu (LTH). A total of 5557 differentially expressed genes (DEGs) were found at four time points during moderate cold stress. Both the DEGs and differentially expressed transcription factor genes were clustered into two groups based on their expression, suggesting a two-phase response to cold stress and a determinative role of transcription factors in the regulation of stress response. The induction of OsDREB2A under cold stress is reported for the first time in this study. Among the anti-oxidant enzyme genes, glutathione peroxidase (GPX) and glutathione S-transferase (GST) were upregulated, suggesting that the glutathione system may serve as the main reactive oxygen species (ROS) scavenger in LTH. Changes in expression of genes in signal transduction pathways for auxin, abscisic acid (ABA) and salicylic acid (SA) imply their involvement in cold stress responses. The induction of ABA response genes and detection of enriched cis-elements in DEGs suggest that ABA signaling pathway plays a dominant role in the cold stress response. Our results suggest that rice responses to cold stress vary with the specific temperature imposed and the rice genotype. PMID:25263631

  15. Semiconductor nanowire optical antenna solar absorbers.

    PubMed

    Cao, Linyou; Fan, Pengyu; Vasudev, Alok P; White, Justin S; Yu, Zongfu; Cai, Wenshan; Schuller, Jon A; Fan, Shanhui; Brongersma, Mark L

    2010-02-10

    Photovoltaic (PV) cells can serve as a virtually unlimited clean source of energy by converting sunlight into electrical power. Their importance is reflected in the tireless efforts that have been devoted to improving the electrical and structural properties of PV materials. More recently, photon management (PM) has emerged as a powerful additional means to boost energy conversion efficiencies. Here, we demonstrate an entirely new PM strategy that capitalizes on strong broad band optical antenna effects in one-dimensional semiconductor nanostructures to dramatically enhance absorption of sunlight. We show that the absorption of sunlight in Si nanowires (Si NWs) can be significantly enhanced over the bulk. The NW's optical properties also naturally give rise to an improved angular response. We propose that by patterning the silicon layer in a thin film PV cell into an array of NWs, one can boost the absorption for solar radiation by 25% while utilizing less than half of the semiconductor material (250% increase in the light absorption per unit volume of material). These results significantly advance our understanding of the way sunlight is absorbed by one-dimensional semiconductor nanostructures and provide a clear, intuitive guidance for the design of efficient NW solar cells. The presented approach is universal to any semiconductor and a wide range of nanostructures; as such, it provides a new PV platform technology. PMID:20078065

  16. Oil well sucker rod shock absorber

    SciTech Connect

    Knox, F.B.

    1986-02-18

    An oil well sucker rod shock absorber is described which consists of: an outer cylindrical casing defined by a cylindrical wall and having a removable upper plug and lower plug disposed respectively at upper and lower extremities of the casing. The upper plug has an axial bore and the lower plug defines a closed lower end and has an upwardly facing top surface. The plunger rod is connected to the sucker rod and is slidably disposed in the bore of the upper plug. A piston within the cylindrical casing is coupled to the plunger rod and has a downwardly facing bottom surface. Biasing means have a maximum vertical length disposed vertically within the casing and extending between the downwardly facing surface of the piston and the upwardly facing surface of the lower plug means at all times. This allows vertical reciprocal translation of the plunger rod and the piston within the cylindrical casing downwardly against the biasing means. Apertures are disposed through the cylindrical casing along the entire length thereof opposite the length of the biasing means, allowing downhole fluid pressure to be applied to the piston within the cylindrical casing via the apertures to be added to the force of the biasing means, without causing a fluid lock within the cylinder. Slap and wear of the sucker rod resulting therefrom are reduced and damage prevented.

  17. Role of TRPM8 and TRPA1 for cold allodynia in patients with cold injury

    Microsoft Academic Search

    Barbara Namer; Inge Petter Kleggetveit; Hermann Handwerker; Martin Schmelz; Ellen Jorum

    2008-01-01

    Local cold injury often induces hypersensitivity to cold and cold allodynia. Sensitisation of TRPM8 or TRPA1 could be the underlying mechanisms. This was evaluated by psychophysics and axon-reflex-flare induction following topical menthol and cinnamaldehyde application in cold injury patients and healthy subjects. The patients had no signs of neuropathy except cold allodynia. We applied 20% cinnamaldehyde and 40% menthol solutions

  18. The blazar GB1428+4217: a warm absorber at z=4.72?

    E-print Network

    A. C. Fabian; A. Celotti; K. Iwasawa; G. Ghisellini

    2001-01-17

    BeppoSAX observations of the high redshift (z=4.72) blazar GB 1428+4217 confirm the presence of a complex soft X-ray spectrum first seen with the ROSAT PSPC. Flattening below a rest frame energy of 5 keV can be accounted for by absorption from an equivalent column density of (cold) gas with N_H ~ 8 x 10^22 cm^-2. Below 2 keV a (variable) excess of a factor ~ 20 above the extrapolated absorbed spectrum is also detected. These findings are consistent with and extend to higher redshifts the correlation between increasing soft X-ray flattening and increasing z, previously pointed out for large samples of radio-loud quasars. We propose that such features, including X-ray absorption, soft excess emission as well as absorption in the optical spectra, can be satisfactorily accounted for by the presence of a highly-ionized nuclear absorber with column N_H ~ 10^23 cm^-2, with properties possibly related to the conditions in the nuclear regions of the host galaxy. High energy X-ray emission consistent with the extrapolation of the medium energy spectrum is detected up to ~ 300 keV (rest frame).

  19. The blazar GB 1428+4217: a warm absorber at z=4.72?

    NASA Astrophysics Data System (ADS)

    Fabian, A. C.; Celotti, A.; Iwasawa, K.; Ghisellini, G.

    2001-06-01

    BeppoSAX observations of the high-redshift (z=4.72) blazar GB 1428+4217 confirm the presence of a complex soft X-ray spectrum first seen with the ROSAT PSPC. Flattening below a rest-frame energy of 5keV can be accounted for by absorption from an equivalent column density of (cold) gas with NH~8×1022cm-2. Below 2keV a (variable) excess of a factor of ~20 above the extrapolated absorbed spectrum is also detected. These findings are consistent with and extend to higher redshifts the correlation between increasing soft X-ray flattening and increasing z, previously pointed out for large samples of radio-loud quasars. We propose that such features, including X-ray absorption and soft excess emission as well as absorption in the optical spectra, can be satisfactorily accounted for by the presence of a highly ionized nuclear absorber with column NH~1023cm-2, with properties possibly related to the conditions in the nuclear regions of the host galaxy. High-energy X-ray emission consistent with the extrapolation of the medium-energy spectrum is detected up to ~300keV (rest frame).

  20. The blazar GB1428+4217 a warm absorber at z=4.72?

    E-print Network

    Fabian, A C; Iwasawa, K; Ghisellini, G

    2001-01-01

    BeppoSAX observations of the high redshift (z=4.72) blazar GB 1428+4217 confirm the presence of a complex soft X-ray spectrum first seen with the ROSAT PSPC. Flattening below a rest frame energy of 5 keV can be accounted for by absorption from an equivalent column density of (cold) gas with N_H ~ 8 x 10^22 cm^-2. Below 2 keV a (variable) excess of a factor ~ 20 above the extrapolated absorbed spectrum is also detected. These findings are consistent with and extend to higher redshifts the correlation between increasing soft X-ray flattening and increasing z, previously pointed out for large samples of radio-loud quasars. We propose that such features, including X-ray absorption, soft excess emission as well as absorption in the optical spectra, can be satisfactorily accounted for by the presence of a highly-ionized nuclear absorber with column N_H ~ 10^23 cm^-2, with properties possibly related to the conditions in the nuclear regions of the host galaxy. High energy X-ray emission consistent with the extrapola...

  1. Hot Topics in Cold Gases

    E-print Network

    Robert Seiringer

    2009-08-25

    Since the first experimental realization of Bose-Einstein condensation in cold atomic gases in 1995 there has been a surge of activity in this field. Ingenious experiments have allowed us to probe matter close to zero temperature and reveal some of the fascinating effects quantum mechanics has bestowed on nature. It is a challenge for mathematical physicists to understand these various phenomena from first principles, that is, starting from the underlying many-body Schr\\"odinger equation. Recent progress in this direction concerns mainly equilibrium properties of dilute, cold quantum gases. We shall explain some of the results in this article, and describe the mathematics involved in understanding these phenomena. Topics include the ground state energy and the free energy at positive temperature, the effect of interparticle interaction on the critical temperature for Bose-Einstein condensation, as well as the occurrence of superfluidity and quantized vortices in rapidly rotating gases.

  2. Carbon nanotube-based tandem absorber with tunable spectral selectivity: transition from near-perfect blackbody absorber to solar selective absorber.

    PubMed

    Selvakumar, N; Krupanidhi, S B; Barshilia, Harish C

    2014-04-23

    CVD grown CNT thin film with a thickness greater than 10 ?m behaves like a near-perfect blackbody absorber (i.e., ?/? = 0.99/0.99). Whereas, for a thickness ? 0.4 µm, the CNT based tandem absorber acts as a spectrally selective coating (i.e., ?/? = 0.95/0.20). These selective coatings exhibit thermal stability up to 650 °C in vacuum, which can be used for solar thermal power generation. PMID:24474148

  3. Composite sandwich constructions for absorbing the electromagnetic waves

    Microsoft Academic Search

    Po Chul Kim; Dai Gil Lee

    2009-01-01

    RAS (radar absorbing structures) is a key component for weapon systems such as aircrafts, warships, and missiles to achieve both the stealth performance by absorbing EM (Electromagnetic) waves incident on and load bearing capability. In this work, the RAS was fabricated as sandwich constructions composed of nanocomposite, carbon fabric\\/epoxy composite, and PVC foam. The nanocomposite composed of E-glass fabric, epoxy

  4. Numerical prediction of absorbing materials via Computational AeroAcoustics

    E-print Network

    Paris-Sud XI, Université de

    contributors, namely 1) the airframe noise, and 2) the propulsive noise. A way for reducing those noisesNumerical prediction of absorbing materials via Computational AeroAcoustics M. Escouflaire and S of the propulsive noise of airplanes, manufacturers are led to generalize the employment of "sound absorbing

  5. The collection of diffuse light onto an extended absorber

    Microsoft Academic Search

    I. M. Bassett; G. H. Derrick

    1978-01-01

    If light comes from a fixed direction and is to be collected onto an absorbing body which is approximately a point or a straight line, it is well known that a mirror of parabolic profile serves the purpose efficiently. If the light is diffuse, or its direction of incidence variable, or if the absorber is not approximately a point or

  6. Optimization of electric shunt resonant circuits for electroacoustic absorbers

    E-print Network

    Paris-Sud XI, Université de

    Optimization of electric shunt resonant circuits for electroacoustic absorbers H. Lissek, R issue is to properly design an electrical matching circuit which, when connected across the transducer as an absorber/reflector of sound, and the electric terminals of which are connected to a dedicated electric load

  7. Radiation doses to cardiovascular system due to absorbed radon

    Microsoft Academic Search

    Jing Chen; Richard B. Richardson

    2005-01-01

    Radon is a naturally occurring radioactive gas. When it is inhaled, a significant proportion of the radon and its progeny deposited in the lung are absorbed into the blood. The absorbed radon delivers radiation doses to all tissues or organs. The thin inner layer of the coronary arteries is probably the primary target tissue of radiation-induced atherosclerosis. A Monte Carlo

  8. Absorbing boundary conditions and optimized Schwarz waveform relaxation

    Microsoft Academic Search

    L. Halpern

    2006-01-01

    We show here how the formalism, introduced by B. Engquist and A. Majda for absorbing boundary conditions, is a powerful tool\\u000a to produce absorbing boundary layers and Schwarz waveform relaxation algorithms, when coupled with best approximation. The\\u000a demonstration is given on the advection diffusion equation, but the ideas apply also to hyperbolic problems.

  9. Engineering, Modeling and Testing of Composite Absorbing Materials for

    E-print Network

    Koledintseva, Marina Y.

    , the materials that would absorb electromagnetic energy in RF, microwave, and potentially mm-wave bands electromagnetic near-fields of the sources, or far-field electromagnetic waves of the given configuration of absorbing materials are of great importance as well. The materials must comply with requirements on thermal

  10. Science on a Roll. Part One: Absorbing Inquiry.

    ERIC Educational Resources Information Center

    Brendzel, Sharon

    2002-01-01

    Presents an activity that tests the absorbency of different brands of paper towels. Suggests making this activity into an open-ended inquiry type of activity. Includes sample questions to guide students, topics for class discussion, and sample methods of using the absorbency activity. (KHR)

  11. Distribution of absorbed doses in the materials irradiated by \\

    Microsoft Academic Search

    A. KolchuzhkinJ; S. Korenev; O. Krivosheev; I. Tropin

    2001-01-01

    This paper describes the experimental setup and presents studies of absorbed doses in different metals and dielectrics along with corresponding Monte Carlo energy deposition simulations. Experiments were conducted using a 5 MeV electron accelerator. We used several Monte Carlo code systems, namely MARS, MCNP, and GEANT to simulate the absorbed doses under the same conditions as in experiment. We compare

  12. Infrared Imaging Video Bolometer with a Double Layer Absorbing Foil

    Microsoft Academic Search

    Igor V. MIROSHNIKOV; Artem Y. KOSTRYUKOV; Byron J. PETERSON

    2007-01-01

    The object of the present paper is an infrared video bolometer with a bolometer foil consisting of two layers: the first layer is constructed of radia tion absorbing blocks and the second layer is a thermal isolating base. The absorbing blocks made of a material with a high photon attenuation coefficient (gold) were spatially separated from each other while the

  13. Infrared Imaging Video Bolometer with a Double Layer Absorbing Foil

    Microsoft Academic Search

    Igor V. Miroshnikov; Artem Y. Kostryukov; Byron J. Peterson

    2008-01-01

    The object of the present paper is an infrared video bolometer with a bolometer foil consisting of two layers: the first layer is constructed of radiation absorbing blocks and the second layer is a thermal isolating base. The absorbing blocks made of a material with a high photon attenuation coefficient (gold) were spatially separated from each other while the base

  14. Absorption properties of carbon black\\/silicon carbide microwave absorbers

    Microsoft Academic Search

    Xiangxuan Liu; Zeyang Zhang; Youpeng Wu

    2011-01-01

    An absorbing medium is prepared using nanosize carbon black (CB) blended with nanosize silicon carbide (SiC). The medium improves the wave absorption properties and the wave band of the single CB absorbent. The microstructure, conductivity, dielectric property, and microwave absorption of the material are studied by means of field emission scanning electron microscopy, trielectrode method, and vector network analyzer respectively.

  15. Measurements of absorbance of hemoglobin solutions incubated with glucose

    Microsoft Academic Search

    Ekaterina N. Lazareva; Valery V. Tuchin; Igor V. Meglinski

    2008-01-01

    This study is focused on the determination of the extinction coefficient of oxyhemoglobin solutions at different concentrations of glucose and hemoglobin incubation with glucose from 3 days to 18 days. The extinction coefficient was determined using absorbance measurements at the wavelength range from 500 nm to 850 nm. Measurements of the absorbance spectra have been performed using fiber-optic spectrometer USB2000

  16. ANALYSIS AND DESIGN OF AN ULTRA-THIN METAMATERIAL ABSORBER

    Microsoft Academic Search

    Ruifeng Huang; Zheng-Wen Li; Ling Bing Kong; Lie Liu; Serguei Matitsine

    2009-01-01

    This paper presents a class of ultra-thin metamaterial absorbers, which consists of periodic microstrip lines on top of a planar lossy substrate backed by a conducting metallic plate. A highly efficient full-wave analysis method was developed to solve the electromagnetic response of the absorbers. The influence of electromagnetic properties of the substrate and physical dimensions of the microstrip lines were

  17. Passive-adaptive vibration absorbers using shape memory alloys

    Microsoft Academic Search

    Keith A. Williams; George T. Chiu; Robert Bernhard

    1999-01-01

    The passive-adaptive approach to vibration control shows promise in its ability to combine the robust stability and low-complexity of passive tuned absorbers with the adaptability of active control schemes. Previous tunable vibration absorbers have been complex and bulky. Shape memory alloys (SMA) with their variable material properties, offer an alternative adaptive mechanism. Heating an SMA causes a change in the

  18. An adaptive tuned vibration absorber based on multilayered MR elastomers

    NASA Astrophysics Data System (ADS)

    Sun, Shuaishuai; Deng, Huaxia; Yang, Jian; Li, Weihua; Du, Haiping; Alici, Gursel; Nakano, Masami

    2015-04-01

    Adaptive tuned vibration absorbers (ATVAs) featuring magnetorheological elastomers (MREs) have attracted considerable research interests because of the advantages of fast response, controllable frequency, and broad working range. Generally, the ATVA uses single layer of MRE sheet, which has some issues such as small oscillator stroke and being effective only on high frequency. In this research, an ATVA which incorporates multilayer MRE sheets was designed and prototyped. Its performance under various scan frequencies was tested on a horizontal vibration platform. A theoretical model was proposed to predict the MRE absorber performance. For the clear demonstration of the advantages of multilayered MRE absorber, two kinds of absorbers with only one layer of MRE were prepared as comparison. The experiments compared the vertical support capability and the tuning frequency range of these two ATVAs, which have clearly highlighted the capabilities of multilayered MRE absorber with larger oscillator stroke (as large as 13.6 mm) and lower working frequencies (as low as 3.2 Hz). The vibration absorption evaluation was conducted by mounting the multilayered MRE absorber on a single-degree-of-freedom system. The results identify that the ATVA with multilayered MREs could work lower than 10 Hz, which is very difficult for the one with single layer MRE. Additionally, the performance of the passive and adaptive tuned laminated MRE absorbers on attenuating a swept frequency vibration are presented, respectively. The ATVA was more effective than the passive absorber over a wide frequency range.

  19. Possible theories of cold fusion

    Microsoft Academic Search

    M. Fleischmann; S. Pons; G. Preparata

    1994-01-01

    Summary  We review some of the key facts in the phenomenology of Pd-hydrides usually referred to as «cold fusion». We conclude that\\u000a all theoretical attempts that concentrate only on few-body interactions, both electromagnetic and nuclear, are probably insufficient\\u000a to explain such phenomena. On the other hand we find good indications that theories describing collective, coherent interactions\\u000a among elementary constituents leading tomacroscopic

  20. Cold cathode vacuum discharge tube

    DOEpatents

    Boettcher, Gordon E. (Albuquerque, NM)

    1998-01-01

    A cold cathode vacuum discharge tube, and method for making same, with an interior surface of the trigger probe coated with carbon deposited by carbon vapor deposition (CVD) or diamond-like carbon (DLC) deposition. Preferably a solid graphite insert is employed in the probe-cathode structure in place of an aluminum bushing employed in the prior art. The CVD or DLC probe face is laser scribed to allow resistance trimming to match available trigger voltage signals and to reduce electrical aging.

  1. Tally of Cold Fusion Papers

    Microsoft Academic Search

    Jed Rothwell

    2009-01-01

    This document contains a tally of cold fusion papers from two sources: the list maintained by Dieter Britz at Aarhus U., and the EndNote database used to generate the indexes at LENR-CANR.org. Various tallies such as the number of peer-reviewed experimental papers are presented. Purpose This report presents some background and a breakdown of the items in two databases of

  2. Acclimatization to cold in humans

    NASA Technical Reports Server (NTRS)

    Kaciuba-Uscilko, Hanna; Greenleaf, John E.

    1989-01-01

    This review focuses on the responses and mechanisms of both natural and artificial acclimatization to a cold environment in mammals, with specific reference to human beings. The purpose is to provide basic information for designers of thermal protection systems for astronauts during intra- and extravehicular activities. Hibernation, heat production, heat loss, vascular responses, body insulation, shivering thermogenesis, water immersion, exercise responses, and clinical symptoms and hypothermia in the elderly are discussed.

  3. Revealing the Properties of Mg II Absorbing Galaxies at z > 1 with HST WFC3/IR

    NASA Astrophysics Data System (ADS)

    Lundgren, Britt; Brammer, Gabriel, , Dr.; York, Donald G.; Chisholm, John P.; Erb, Dawn; Kulkarni, Varsha P.; Straka, Lorrie; Tremonti, Christina A.; Van Dokkum, Pieter G.; Wake, David

    2015-01-01

    Intervening absorption from Mg II in the spectra of distant quasars is understood to trace the tidal stripping, accretion and outflows of cold, enriched gas in the circumgalactic medium of galaxies, independent of luminosity, to high redshift. Tens of thousands of Mg II absorbers in the range 0.3 < z < 2.2 have been extracted to date from the SDSS spectroscopic quasar sample, but their utility in aiding our understanding of the gaseous processes driving galaxy evolution has been hindered by the observational difficulties of detecting their host galaxies at intermediate and high redshifts and at small angular separations from brighter background quasars. We present first results from an 18-orbit HST Cycle 21 WFC3/IR program, which has obtained direct imaging and grism observations of galaxies in the fields surrounding the 9 quasar sight lines in the SDSS with the highest frequency of uncorrelated foreground Mg II absorption in the range 0.7< z < 2.2. These highly efficient observations include 56 Mg II absorbers, most all of which are matched unambiguously to galaxies in the grism data, thereby doubling the number of spectroscopically confirmed Mg II absorbing galaxies at z > 1. The data further enable precise measurements of the impact parameters, morphologies, inclination angles, star formation rates, and star formation rate surface densities of typical Mg II-selected galaxies, as a function of Mg II absorption strength, which are complete for a large range in projected separations (7-450 kpc) and to low star formation rates (~1.3 Msun/yr).

  4. XMM-Newton Observations of the Heavily Absorbed Seyfert 1 Galaxy IC 4329A

    SciTech Connect

    Steenbrugge, K.

    2005-01-05

    We detect seven distinct absorbing systems in the high-resolution X-ray spectrum of the Seyfert 1 galaxy IC 4329A, taken with XMM-Newton. Firstly we detect absorption due to cold gas in our own Galaxy and warm gas in the Galactic halo or the Local Group. This local warm gas is only detected through O VII absorption, from which we deduce a temperature between 0.03 and 0.2 keV. In IC 4329A we detect absorption from the host galaxy as well as from a warm absorber, close to the nucleus, which has 4 components. The absorption from the host galaxy is well modeled by neutral material. The warm absorber detected in IC 4329A is photoionized and has an ionization range between log {xi} = -1.37 and log {xi} = 2.7. A broad excess is measured at the O VIII Ly{alpha} and N VII Ly{alpha} emission lines, which can be modeled by either disklines or multiple Gaussians. From the lightcurve we find that the source changed luminosity by about 20 % over the 140 ks observation, while the spectral shape, i.e. the softness ratio did not vary. In the EPIC spectra a narrow Fe K{alpha} and Fe XXVI Ly{alpha} emission line are detected. The narrowness of the Fe K{alpha} line and the fact that there is no evidence for flux variability between different observations leads us to conclude that the Fe K{alpha} line is formed at a large distance from the central black hole.

  5. Cold cathode vacuum gauging system

    DOEpatents

    Denny, Edward C. (Knoxville, TN)

    2004-03-09

    A vacuum gauging system of the cold cathode type is provided for measuring the pressure of a plurality of separate vacuum systems, such as in a gas centrifuge cascade. Each casing is fitted with a gauge tube assembly which communicates with the vacuum system in the centrifuge casing. Each gauge tube contains an anode which may be in the form of a slender rod or wire hoop and a cathode which may be formed by the wall of the gauge tube. The tube is provided with an insulated high voltage connector to the anode which has a terminal for external connection outside the vacuum casing. The tube extends from the casing so that a portable magnet assembly may be inserted about the tube to provide a magnetic field in the area between the anode and cathode necessary for pressure measurements in a cold cathode-type vacuum gauge arrangement. The portable magnetic assembly is provided with a connector which engages the external high voltage terminal for providing power to the anode within in the gauge tube. Measurement is made in the same manner as the prior cold cathode gauges in that the current through the anode to the cathode is measured as an indication of the pressure. By providing the portable magnetic assembly, a considerable savings in cost, installation, and maintenance of vacuum gauges for pressure measurement in a gas centrifuge cascade is realizable.

  6. Micro-Kelvin cold molecules.

    SciTech Connect

    Strecker, Kevin E.; Chandler, David W.

    2009-10-01

    We have developed a novel experimental technique for direct production of cold molecules using a combination of techniques from atomic optical and molecular physics and physical chemistry. The ability to produce samples of cold molecules has application in a broad spectrum of technical fields high-resolution spectroscopy, remote sensing, quantum computing, materials simulation, and understanding fundamental chemical dynamics. Researchers around the world are currently exploring many techniques for producing samples of cold molecules, but to-date these attempts have offered only limited success achieving milli-Kelvin temperatures with low densities. This Laboratory Directed Research and Development project is to develops a new experimental technique for producing micro-Kelvin temperature molecules via collisions with laser cooled samples of trapped atoms. The technique relies on near mass degenerate collisions between the molecule of interest and a laser cooled (micro-Kelvin) atom. A subset of collisions will transfer all (nearly all) of the kinetic energy from the 'hot' molecule, cooling the molecule at the expense of heating the atom. Further collisions with the remaining laser cooled atoms will thermally equilibrate the molecules to the micro-Kelvin temperature of the laser-cooled atoms.

  7. Bank erosion in cold regions

    SciTech Connect

    Gatto, L.W. (Army Cold Regions Research and Engineering Lab., Hanover, NH (United States). Geological Sciences Branch)

    1993-03-01

    River and lake bank erosion is caused by multiple processes and influenced by many conditions that interact in complex ways. Their importance will vary spatially and temporally due in large part to regional and seasonal differences in climate, hydrology and soils. In cold areas, these normally complex interactions are further complicated because the same process or condition may cause erosion at one time and prevent erosion at another. Bank sediments when frozen may be more resistant to erosion than when unfrozen. However, during the process of freezing, soil structure can be disrupted and sediment pore water can be drawn to the freezing zone within the soil; ice formation may make bank sediment more susceptible to erosion during spring thaw. Ice that has been forced onto and piled upon a shore by wind or thermal expansion can cause considerable localized damage and yet can also protect shores against winter waves and nearshore currents. Ice push can form sediment ramparts that protect the toe of a bank. Spray from winds and waves can freeze to banks, covering them with a protective layer of ice. When river or lake water levels are high enough, however, ice can erode banks by shoving, gouging and disrupting bank sediment. This paper reviews the state of knowledge regarding the importance of cold regions factors in determining the erodibility and erosion of bank sediments. Ongoing investigations to improve methods of erosion prediction in cold climates will also be detailed.

  8. HOM absorbers for ERL cryomodules at BNL

    SciTech Connect

    Hahn,H.; Ben-Zvi, I.; Hammons, L.; Xu, W.

    2009-09-20

    The physics needs and technical requirements for several future accelerator projects at the Relativistic Heavy Ion Collider (RHIC) all involve electron Energy Recovery Linacs (ERL). The required high-current, high-charge operating parameters make effective higher-order-mode (HOM) damping mandatory and the development of HOM dampers for a prototypical five-cell cavity is actively pursued. An experimental five-cell niobium cavity with ferrite dampers has been constructed, and effective HOM damping has been demonstrated at room and superconducting (SC) temperatures. A novel type of ferrite damper around a ceramic break has been developed for the ERL electron gun and prototype tests are also reported. Contemplated future projects are based on assembling a chain of superconducting cavities in a common cryomodule with the dampers placed in the cold space between the cavities, imposing severe longitudinal space constraints. Various damper configurations have been studied by placing them between two five-cell copper cavities. Measured and simulated copper cavity results, external Q-values of possible dampers and fundamental mode losses are presented.

  9. Thermally Induced Nonlinear Optical Absorption in Metamaterial Perfect Absorbers

    E-print Network

    Guddala, Sriram; Ramakrishna, S Anantha

    2015-01-01

    A metamaterial perfect absorber consisting of a tri-layer (Al/ZnS/Al) metal-dielectric-metal system with top aluminium nano-disks is fabricated by laser-interference lithography and lift-off processing. The metamaterial absorber had peak resonant absorbance at 1090 nm and showed nonlinear absorption for 600ps laser pulses at 1064 nm wavelength. A nonlinear saturation of reflectance was measured to be dependent on the average laser power incident and not the peak laser intensity. The nonlinear behaviour is shown to arise from the heating due to the absorbed radiation and photo-thermal changes in the dielectric properties of aluminium. The metamaterial absorber is seen to be damage resistant at large laser intensities of 25 MW/cm2.

  10. Thermally induced nonlinear optical absorption in metamaterial perfect absorbers

    NASA Astrophysics Data System (ADS)

    Guddala, Sriram; Kumar, Raghwendra; Ramakrishna, S. Anantha

    2015-03-01

    A metamaterial perfect absorber consisting of a tri-layer (Al/ZnS/Al) metal-dielectric-metal system with top aluminium nano-disks was fabricated by laser-interference lithography and lift-off processing. The metamaterial absorber had peak resonant absorbance at 1090 nm and showed nonlinear absorption for 600ps laser pulses at 1064 nm wavelength. A nonlinear saturation of reflectance was measured to be dependent on the average laser power incident and not the peak laser intensity. The nonlinear behaviour is shown to arise from the heating due to the absorbed radiation and photo-thermal changes in the dielectric properties of aluminium. The metamaterial absorber is seen to be damage resistant at large laser intensities of 25 MW/cm2.

  11. Absorbing WIPP brines : a TRU waste disposal strategy.

    SciTech Connect

    Yeamans, D. R. (David R.); Wright, R. (Robert)

    2002-01-01

    Los Alamos National Laboratory (LANL) has completed experiments involving 15 each, 250-liter experimental test containers of transuranic (TRU) heterogeneous waste immersed in two types of brine similar to those found in the underground portion of the Waste Isolation Pilot Plant (WIPP). To dispose of the waste without removing the brine from the test containers, LANL added commercially available cross-linked polyacrylate granules to absorb the 190 liters of brine in each container, making the waste compliant for shipping to the WlPP in a Standard Waste Box (SWB). Prior to performing the absorption, LANL and the manufacturer of the absorbent conducted laboratory and field tests to determine the ratio of absorbent to brine that would fully absorb the liquid. Bench scale tests indicated a ratio of 10 parts Castile brine to one part absorbent and 6.25 parts Brine A to one part absorbent. The minimum ratio of absorbent to brine was sought because headspace in the containers was limited. However, full scale testing revealed that the ratio should be adjusted to be about 15% richer in absorbent. Additional testing showed that the absorbent would not apply more than 13.8 kPa pressure on the walls of the vessel and that the absorbent would still function normally at that pressure and would not degrade in the approximately 5e-4 Sv/hr radioactive field produced by the waste. Heat generation from the absorption was minimal. The in situ absorption created a single waste stream of 8 SWBs whereas the least complicated alternate method of disposal would have yielded at least an additional 2600 liters of mixed low level liquid waste plus about two cubic meters of mixed low level solid waste, and would have resulted in higher risk of radiation exposure to workers. The in situ absorption saved $3 1 lk in a combination of waste treatment, disposal, material and personnel costs compared to the least expensive alternative and $984k compared to the original plan.

  12. ABSORBING WIPP BRINES: A TRU WASTE DISPOSAL STRATEGY

    SciTech Connect

    Yeamans, D. R.; Wrights, R. S.

    2002-02-25

    Los Alamos National Laboratory (LANL) has completed experiments involving 15 each, 250- liter experimental test containers of transuranic (TRU) heterogeneous waste immersed in two types of brine similar to those found in the underground portion of the Waste Isolation Pilot Plant (WIPP). To dispose of the waste without removing the brine from the test containers, LANL added commercially available cross-linked polyacrylate granules to absorb the 190 liters of brine in each container, making the waste compliant for shipping to the WIPP in a Standard Waste Box (SWB). Prior to performing the absorption, LANL and the manufacturer of the absorbent conducted laboratory and field tests to determine the ratio of absorbent to brine that would fully absorb the liquid. Bench scale tests indicated a ratio of 10 parts Castile brine to one part absorbent and 6.25 parts Brine A to one part absorbent. The minimum ratio of absorbent to brine was sought because headspace in the containers was limited. However, full scale testing revealed that the ratio should be adjusted to be about 15% richer in absorbent. Additional testing showed that the absorbent would not apply more than 13.8 kPa pressure on the walls of the vessel and that the absorbent would still function normally at that pressure and would not degrade in the approximately 5e-4 Sv/hr radioactive field produced by the waste. Heat generation from the absorption was minimal. The in situ absorption created a single waste stream of 8 SWBs whereas the least complicated alternate method of disposal would have yielded at least an additional 2600 liters of mixed low level liquid waste plus about two cubic meters of mixed low level solid waste, and would have resulted in higher risk of radiation exposure to workers. The in situ absorption saved $311k in a combination of waste treatment, disposal, material and personnel costs compared to the least expensive alternative and $984k compared to the original plan.

  13. Application of a new isotropic absorbing boundary condition (ABC) with PML in optimal chiral absorbing condition research

    Microsoft Academic Search

    Wang Nan; Tan Wei

    2008-01-01

    A new absorbing boundary condition (ABC) with PML for isotropic medium is deduced by functional way without D'Alembertian annihilation or factorization technique. Then, the new ABC is applied to optimal chiral medium absorbing condition research and hollow chiral sphere shielding effectiveness research.

  14. A Parallel\\/Series Array of Cold-Electron Bolometers with SIN Tunnel Junctions for Cosmology Instruments

    Microsoft Academic Search

    Leonid Kuzmin

    A novel concept of the parallel\\/series array of Cold-Electron Bolometers (CEB) with Superconductor-Insulator-Normal (SIN) Tunnel Junctions has been proposed for matching with JFET readout. The current-biased CEBs are connected in series for DC and in parallel for HF signal. A signal is concentrated to the absorber through the capacitance of tunnel junctions and additional capacitance for coupling of superconducting islands.

  15. Cold Fusion Has Now Come Out of the Cold

    NASA Astrophysics Data System (ADS)

    Storms, Edmund

    2003-10-01

    The phenomenon called cold fusion or LENR (Low-Energy-Nuclear-Reaction) has now achieved a level of reproducibility and understanding that warrants re-examination of the claims. A summary of what is known and want is being done worldwide to obtain more knowledge will be given. Rather than disappearing as better data are obtained, the effects are becoming more reproducible and of greater magnitude. Justification for this claim can be obtained at www.LENR-CANR.org. The phenomenon is too important to ignore any longer even though it conflicts with conventional theory.

  16. Some Chinese folk prescriptions for wind-cold type common cold

    PubMed Central

    Hai-long, Zhai; Shimin, Chen; Yalan, Lu

    2015-01-01

    Although self-limiting, the common cold (??g?n mào) is highly prevalent. There are no effective antivirals to cure the common cold and few effective measures to prevent it, However, for thousands years, Chinese people have treated the common cold with natural herbs, According to the traditional Chinese medicine (TCM) theory (???? zh?ng y? l? lùn), the common cold is considered as an exterior syndrome, which can be further divided into the wind-cold type (??? f?ng hán xíng), the wind-heat type (??? f?ng rè xíng), and the summer heat dampness type (??? sh? rè xíng). Since the most common type of common cold caught in winter and spring is the wind-cold type, the article introduced some Chinese folk prescriptions for the wind-cold type common cold with normal and weak physique, respectively. For thousands of years, Chinese folk prescriptions for the common cold, as complementary and alternative medicine (CAM; ??????? b? ch?ng y? tì dài y? xué), have been proven to be effective, convenient, cheap, and most importantly, safe. The Chinese folk prescriptions (?????? zh?ng guó mín ji?n ch? f?ng) for the wind-cold type common cold are quite suitable for general practitioners or patients with the wind-cold type common cold, to treat the disease. Of course, their pharmacological features and mechanisms of action need to be further studied.

  17. Some Chinese folk prescriptions for wind-cold type common cold.

    PubMed

    Hai-Long, Zhai; Shimin, Chen; Yalan, Lu

    2015-07-01

    Although self-limiting, the common cold (g?n mào) is highly prevalent. There are no effective antivirals to cure the common cold and few effective measures to prevent it, However, for thousands years, Chinese people have treated the common cold with natural herbs, According to the traditional Chinese medicine (TCM) theory ( zh?ng y? l? lùn), the common cold is considered as an exterior syndrome, which can be further divided into the wind-cold type ( f?ng hán xíng), the wind-heat type ( f?ng rè xíng), and the summer heat dampness type ( sh? rè xíng). Since the most common type of common cold caught in winter and spring is the wind-cold type, the article introduced some Chinese folk prescriptions for the wind-cold type common cold with normal and weak physique, respectively. For thousands of years, Chinese folk prescriptions for the common cold, as complementary and alternative medicine (CAM; b? ch?ng y? tì dài y? xué), have been proven to be effective, convenient, cheap, and most importantly, safe. The Chinese folk prescriptions ( zh?ng guó mín ji?n ch? f?ng) for the wind-cold type common cold are quite suitable for general practitioners or patients with the wind-cold type common cold, to treat the disease. Of course, their pharmacological features and mechanisms of action need to be further studied. PMID:26151024

  18. Simulation, Fabrication and Characterization of THz Metamaterial Absorbers

    PubMed Central

    Grant, James P.; McCrindle, Iain J.H.; Cumming, David R.S.

    2012-01-01

    Metamaterials (MM), artificial materials engineered to have properties that may not be found in nature, have been widely explored since the first theoretical1 and experimental demonstration2 of their unique properties. MMs can provide a highly controllable electromagnetic response, and to date have been demonstrated in every technologically relevant spectral range including the optical3, near IR4, mid IR5 , THz6 , mm-wave7 , microwave8 and radio9 bands. Applications include perfect lenses10, sensors11, telecommunications12, invisibility cloaks13 and filters14,15. We have recently developed single band16, dual band17 and broadband18 THz metamaterial absorber devices capable of greater than 80% absorption at the resonance peak. The concept of a MM absorber is especially important at THz frequencies where it is difficult to find strong frequency selective THz absorbers19. In our MM absorber the THz radiation is absorbed in a thickness of ~ ?/20, overcoming the thickness limitation of traditional quarter wavelength absorbers. MM absorbers naturally lend themselves to THz detection applications, such as thermal sensors, and if integrated with suitable THz sources (e.g. QCLs), could lead to compact, highly sensitive, low cost, real time THz imaging systems. PMID:23299442

  19. Thin-film absorber for a solar collector

    SciTech Connect

    Wilhelm, W.G.

    1982-02-09

    This invention pertains to energy absorbers for solar collectors, and more particularly to high performance thin film absorbers. The solar collectors comprising the absorber of this invention overcome several problems seen in current systems, such as excessive hardware, high cost and unreliability. In the preferred form, the apparatus features a substantially rigid planar frame with a thin film window bonded to one planar side of the frame. An absorber in accordance with the present invention is comprised of two thin film layers that are sealed perimetrically. In a preferred embodiment, thin film layers are formed from a metal/plastic laminate. The layers define a fluid-tight planar envelope of large surface area to volume through which a heat transfer fluid flows. The absorber is bonded to the other planar side of the frame. The thin film construction of the absorber assures substantially full envelope wetting and thus good efficiency. The window and absorber films stress the frame adding to the overall strength of the collector.

  20. Microwave absorbance properties of zirconium–manganese substituted cobalt nanoferrite as electromagnetic (EM) wave absorbers

    SciTech Connect

    Khan, Kishwar, E-mail: kknano@hotmail.com; Rehman, Sarish

    2014-02-01

    Highlights: • Good candidates for EM materials with low reflectivity. • Good candidates for broad bandwidth at microwave frequency. • Microwave absorbing bandwidth was modulated simply by manipulating the Zr–Mn. • Higher the Zr–Mn content, the higher absorption rates for the electromagnetic radiation. • The predicted reflection loss shows that this can be used for thin ferrite absorber. - Abstract: Nanocrystalline Zr–Mn (x) substituted Co ferrite having chemical formula CoFe{sub 2?2x}Zr{sub x}Mn{sub x}O{sub 4} (x = 0.1–0.4) was prepared by co-precipitation technique. Combining properties such as structural, electrical, magnetic and reflection loss characteristics. Crystal structure and surface morphology of the calcined samples were characterized by X-ray diffraction analysis (XRD) and scanning electron microscopy (SEM). By using two point probe homemade resistivity apparatus to find resistivity of the sample. Electromagnetic (EM) properties are measured through RF impedance/materials analyzer over 1 MHz–3 GHz. The room-temperature dielectric measurements show dispersion behavior with increasing frequency from 100 Hz to 3 MHz. Magnetic properties confirmed relatively strong dependence of saturation magnetization on Zr–Mn composition. Curie temperature is also found to decrease linearly with addition of Zr–Mn. Furthermore, comprehensive analysis of microwave reflection loss (RL) is carried out as a function of substitution, frequency, and thickness. Composition accompanying maximum microwave absorption is suggested.

  1. Development of a New TES Structure Using a Radiation Absorber Self-Adjusting the Operating Temperature

    Microsoft Academic Search

    Masashi Ohno; Hiroyuki Takahashi; Kentaro Nishimura; Yasuhiro Minamikawa; Rathnayaka Mudiyanselage Thushara Damayanthi; Hiromi Sato; Chiko Otani; Hidenori Toyokawa; Hajime Tanida; Tomoya Uruga

    2009-01-01

    We propose a new structure of a TES and a series connection of radiation absorber, which can stabilize the absorber temperature through a negative feedback process in the absorber. We consider that this structure of the self-heating absorber might allow TES to improve detection efficiency with large effective area and high count rate by the cooling power inside the absorber.

  2. Automated Absorber Attachment for X-ray Microcalorimeter Arrays

    NASA Technical Reports Server (NTRS)

    Moseley, S.; Allen, Christine; Kilbourne, Caroline; Miller, Timothy M.; Costen, Nick; Schulte, Eric; Moseley, Samuel J.

    2007-01-01

    Our goal is to develop a method for the automated attachment of large numbers of absorber tiles to large format detector arrays. This development includes the fabrication of high quality, closely spaced HgTe absorber tiles that are properly positioned for pick-and-place by our FC150 flip chip bonder. The FC150 also transfers the appropriate minute amount of epoxy to the detectors for permanent attachment of the absorbers. The success of this development will replace an arduous, risky and highly manual task with a reliable, high-precision automated process.

  3. HS 1603+3820 and its Warm Absorber

    NASA Astrophysics Data System (ADS)

    Niko?ajuk, M.; Ró?a?ska, A.; Czerny, B.; Dobrzycki, A.

    2009-07-01

    We use photoionization codes CLOUDY and TITAN to obtain physical conditions in the absorbing medium close to the nucleus of a distant quasar (z = 2.54) HS 1603+3820. We found that the total column density of this Warm Absorber is 2 x 1022 cm-2. Due to the softness of the quasars spectrum the modelling allowed us also to determine uniquely the volume hydrogen density of this warm gas (n = 1010 cm-3) which combined with the other quasar parameters leads to a distance determination to the Warm Absorber from the central source which is ~ 1.5 x 1016 cm.

  4. Optimization of the acoustic absorption coefficients of certain functional absorbents

    NASA Technical Reports Server (NTRS)

    Pocsa, V.; Biborosch, L.; Veres, A.; Halpert, E.; Lorian, R.; Botos, T.

    1974-01-01

    The sound absorption coefficients of some functional absorbents (mineral wool plates) are determined by the reverberation chamber method. The influence of the angle of inclination of the sound absorbing material with respect to the surface to be treated is analyzed as well as the influence of the covering index, defined as the ratio of the designed area of a plate and the area of the treated surface belonging to another plate. As compared with the conventional method of applying sound-absorbing plates, the analyzed structures have a higher technological and economical efficiency. The optimum structure corresponds to an angle of inclination of 15 deg and a covering index of 0.8.

  5. Fundamental research on oscillating water column wave power absorbers

    SciTech Connect

    Maeda, H.; Kato, W.; Kinoshita, T.; Masuda, K.

    1985-03-01

    An oscillating water column (OWC) wave power absorber is one of the most promising devices, as well as the Salter Duck and the Clam. This paper presents a simple prediction method, in which the equivalent floating body approximation is used, for absorbing wave power characteristics of an oscillating water column device. The effects of the compressibility of air and inertia of an air turbine and electric generator on absorbed wave power are obtained by using the equivalent electric circuit concept. Both the experimental and theoretical studies are carried out in this paper.

  6. Cold cathode vacuum discharge tube

    DOEpatents

    Boettcher, G.E.

    1998-03-10

    A cold cathode vacuum discharge tube, and method for making same, are disclosed with an interior surface of the trigger probe coated with carbon deposited by carbon vapor deposition (CVD) or diamond-like carbon (DLC) deposition. Preferably a solid graphite insert is employed in the probe-cathode structure in place of an aluminum bushing employed in the prior art. The CVD or DLC probe face is laser scribed to allow resistance trimming to match available trigger voltage signals and to reduce electrical aging. 15 figs.

  7. Cold cathode vacuum discharge tube

    DOEpatents

    Boettcher, G.E.

    1998-04-14

    A cold cathode vacuum discharge tube, and method for making same, with an interior surface of the trigger probe coated with carbon deposited by chemical vapor deposition (CVD) or diamond-like carbon (DLC) deposition are disclosed. Preferably a solid graphite insert is employed in the probe-cathode structure in place of an aluminum bushing employed in the prior art. The CVD or DLC probe face is laser scribed to allow resistance trimming to match available trigger voltage signals and to reduce electrical aging. 14 figs.

  8. Probing Cold Dense Nuclear Matter

    SciTech Connect

    Subedi, Ramesh; Shneor, R.; Monaghan, Peter; Anderson, Bryon; Aniol, Konrad; Annand, John; Arrington, John; Benaoum, Hachemi; Benmokhtar, Fatiha; Bertozzi, William; Boeglin, Werner; Chen, Jian-Ping; Choi, Seonho; Cisbani, Evaristo; Craver, Brandon; Frullani, Salvatore; Garibaldi, Franco; Gilad, Shalev; Gilman, Ronald; Glamazdin, Oleksandr; Hansen, Jens-Ole; Higinbotham, Douglas; Holmstrom, Timothy; Ibrahim, Hassan; Igarashi, Ryuichi; De Jager, Cornelis; Jans, Eddy; Jiang, Xiaodong; Kaufman, Lisa; Kelleher, Aidan; Kolarkar, Ameya; Kumbartzki, Gerfried; LeRose, John; Lindgren, Richard; Liyanage, Nilanga; Margaziotis, Demetrius; Markowitz, Pete; Marrone, Stefano; Mazouz, Malek; Meekins, David; Michaels, Robert; Moffit, Bryan; Perdrisat, Charles; Piasetzky, Eliazer; Potokar, Milan; Punjabi, Vina; Qiang, Yi; Reinhold, Joerg; Ron, Guy; Rosner, Guenther; Saha, Arunava; Sawatzky, Bradley; Shahinyan, Albert; Sirca, Simon; Slifer, Karl; Solvignon, Patricia; Sulkosky, Vince; Sulkosky, Vincent; Sulkosky, Vince; Sulkosky, Vincent; Urciuoli, Guido; Voutier, Eric; Watson, John; Weinstein, Lawrence; Wojtsekhowski, Bogdan; Wood, Stephen; Zheng, Xiaochao; Zhu, Lingyan

    2008-06-01

    The protons and neutrons in a nucleus can form strongly correlated nucleon pairs. Scattering experiments, in which a proton is knocked out of the nucleus with high-momentum transfer and high missing momentum, show that in carbon-12 the neutron-proton pairs are nearly 20 times as prevalent as proton-proton pairs and, by inference, neutron-neutron pairs. This difference between the types of pairs is due to the nature of the strong force and has implications for understanding cold dense nuclear systems such as neutron stars.

  9. Compressibility of cold catalyzed matter

    NASA Astrophysics Data System (ADS)

    Haensel, P.

    1980-10-01

    The properties of cold catalyzed matter (CCM) of density near and above the density characteristic of the central region of heavy atomic nuclei are of fundamental importance for the physics of neutron stars. In this paper the compression modulus of CCM (an electrically neutral, spatially homogeneous mixture of electrons, neutrons, and protons at a temperature of 0 K) is studied for nucleon number density in the range 0.15-0.4 per cu fm. To a very good approximation the compression modulus is given by the nucleon contribution calculated at a fixed composition of the matter.

  10. Axinos as Cold Dark Matter

    SciTech Connect

    Covi, Laura [DESY, Notkestrasse 85, D-22603 Hamburg (Germany)

    2006-11-28

    The connection of Dark Matter (DM) to our particle physics model is still one of the open cosmological questions. In these proceedings I will argue that axinos can be successful Cold Dark Matter candidates in models with Supersymmetry and the Peccei-Quinn solution of the strong CP problem. If they are the Lightest Supersymmetric Particle (LSP), they can be produced in the right abundance by thermal scatterings and out of equilibrium decays of the Next-to-Lightest Supersymmetric Particles (NLSPs). Moreover if the NLSPs are charged, their decay could help us understand which is the LSP, e.g. between axino and gravitino.

  11. International workshop on cold neutron sources

    SciTech Connect

    Russell, G.J.; West, C.D. (comps.) (Los Alamos National Lab., NM (United States)) [comps.; Los Alamos National Lab., NM (United States)

    1991-08-01

    The first meeting devoted to cold neutron sources was held at the Los Alamos National Laboratory on March 5--8, 1990. Cosponsored by Los Alamos and Oak Ridge National Laboratories, the meeting was organized as an International Workshop on Cold Neutron Sources and brought together experts in the field of cold-neutron-source design for reactors and spallation sources. Eighty-four people from seven countries attended. Because the meeting was the first of its kind in over forty years, much time was spent acquainting participants with past and planned activities at reactor and spallation facilities worldwide. As a result, the meeting had more of a conference flavor than one of a workshop. The general topics covered at the workshop included: Criteria for cold source design; neutronic predictions and performance; energy deposition and removal; engineering design, fabrication, and operation; material properties; radiation damage; instrumentation; safety; existing cold sources; and future cold sources.

  12. TRPA1 Contributes to Cold Hypersensitivity

    PubMed Central

    Camino, Donato del; Murphy, Sarah; Heiry, Melissa; Barrett, Lee B.; Earley, Taryn J.; Cook, Colby A.; Petrus, Matt J.; Zhao, Michael; D'Amours, Marc; Deering, Nate; Brenner, Gary J.; Costigan, Michael; Hayward, Neil J.; Chong, Jayhong A.; Fanger, Christopher M.; Woolf, Clifford J.; Patapoutian, Ardem; Moran, Magdalene M.

    2010-01-01

    TRPA1 is a non-selective cation channel expressed by nociceptors. While it is widely accepted that TRPA1 serves as a broad irritancy receptor for a variety of reactive chemicals, its role in cold sensation remains controversial. Here, we demonstrate that mild cooling markedly increases agonist-evoked rat TRPA1 currents. In the absence of an agonist, even noxious cold only increases current amplitude slightly. These results suggest that TRPA1 is a key mediator of cold hypersensitivity in pathological conditions where reactive oxygen species and pro-inflammatory activators of the channel are present, but likely plays a comparatively minor role in acute cold sensation. Supporting this, cold hypersensitivity can be induced in wild-type but not Trpa1-/- mice by subcutaneous administration of a TRPA1 agonist. Furthermore, the selective TRPA1 antagonist HC-030031 reduces cold hypersensitivity in rodent models of inflammatory and neuropathic pain. PMID:21068322

  13. Simulations of a cold-air pool associated with elevated wintertime ozone in the Uintah Basin, Utah

    NASA Astrophysics Data System (ADS)

    Neemann, E. M.; Crosman, E. T.; Horel, J. D.; Avey, L.

    2014-06-01

    Numerical simulations are used to investigate the meteorological characteristics of the 1-6 February 2013 cold-air pool in the Uintah Basin, Utah, and the resulting high ozone concentrations. Flow features affecting cold-air pools and air quality in the Uintah Basin are studied, including: penetration of clean air into the basin from across the surrounding mountains, elevated easterlies within the inversion layer, and thermally-driven slope and valley flows. The sensitivity of the boundary layer structure to cloud microphysics and snow cover variations are also examined. Ice-dominant clouds enhance cold-air pool strength compared to liquid-dominant clouds by increasing nocturnal cooling and decreasing longwave cloud forcing. Snow cover increases boundary layer stability by enhancing the surface albedo, reducing the absorbed solar insolation at the surface, and lowering near-surface air temperatures. Snow cover also increases ozone levels by enhancing solar radiation available for photochemical reactions.

  14. Optical precursor with four-wave mixing and storage based on a cold-atom ensemble.

    PubMed

    Ding, Dong-Sheng; Jiang, Yun Kun; Zhang, Wei; Zhou, Zhi-Yuan; Shi, Bao-Sen; Guo, Guang-Can

    2015-03-01

    We observed optical precursors in four-wave mixing based on a cold-atom gas. Optical precursors appear at the edges of pulses of the generated optical field, and propagate through the atomic medium without absorption. Theoretical analysis suggests that these precursors correspond to high-frequency components of the signal pulse, which means the atoms cannot respond quickly to rapid changes in the electromagnetic field. In contrast, the low-frequency signal components are absorbed by the atoms during transmission. We also showed experimentally that the backward precursor can be stored using a Raman transition of the atomic ensemble and retrieved later. PMID:25793813

  15. Isocurvature cold dark matter fluctuations

    NASA Technical Reports Server (NTRS)

    Efstathiou, G.; Bond, J. R.

    1986-01-01

    According to Preskill et al. (1983), the axion field represents a particularly attractive candidate for the dark matter in the universe. In many respects it behaves like other forms of cold dark matter, such as massive gravitinos, photinos, and monopoles. It is, however, a pseudo-Goldstone boson of very low mass, and it is only because of rapid coherent oscillations of the field that it can dominate the mass density of the universe. In the present paper it is assumed that the isocurvature mode is dominant. The linear evolution calculations conducted do not depend upon specific details of particle physics. For this reason, the conducted discussion is applicable to any cold dark matter model with isocurvature perturbations. The results of the study lead to the conclusion that scale-invariant isocurvature perturbations do not seem an attractive possibility for the origin of large-scale structure. The findings strengthen the review that primordial adiabatic perturbations were the dominant fluctuations in the early stages of the Big Bang.

  16. Cold as a therapeutic agent.

    PubMed

    Wang, H; Olivero, W; Wang, D; Lanzino, G

    2006-05-01

    The use of cold as a therapeutic agent has a long and colorful history. The Edwin Smith Papyrus, the most ancient medical text known, dated 3500 B.C., made numerous references to the use of cold as therapy. Baron de Larrey, a French army surgeon during Napoleon's Russian campaign, packed the limbs in ice prior to amputations to render the procedures painless. In the early twentieth century, a neurosurgeon, Temple Fay, pioneered "human refrigeration" as a treatment for malignancies and head injuries. In 1961, Irving Cooper developed the first closed cryoprobe system and ushered in the modern era of cryogenic surgery with his imperturbable convictions. Fay's early work fell victim to the disruptive sequel of the World War II. The Nazis confiscated his data (presented before the Third International Cancer Congress in 1939) forwarded to Belgium for publication and brutally applied his refrigeration techniques experimentally without any benefit of anesthesia in the concentration camps, especially Dachau. Hypothermia became associated in the public mind with the atrocities exposed at the war trials in Nürnberg. After lying dormant for decades, the interest was rekindled in the late 80s when mild hypothermia was shown to confer dramatic neuroprotection in a number of experimental models of brain injury. With several large multi-center clinical studies currently under way, hypothermia is receiving unprecedented attention from the medical and scientific communities. PMID:16489500

  17. Cold vacuum drying facility design requirements

    SciTech Connect

    IRWIN, J.J.

    1999-07-01

    This document provides the detailed design requirements for the Spent Nuclear Fuel Project Cold Vacuum Drying Facility. Process, safety, and quality assurance requirements and interfaces are specified.

  18. Review on Cold-Formed Steel Connections

    PubMed Central

    Tan, Cher Siang; Mohammad, Shahrin; Md Tahir, Mahmood; Shek, Poi Ngian

    2014-01-01

    The concept of cold-formed light steel framing construction has been widespread after understanding its structural characteristics with massive research works over the years. Connection serves as one of the important elements for light steel framing in order to achieve its structural stability. Compared to hot-rolled steel sections, cold-formed steel connections perform dissimilarity due to the thin-walled behaviour. This paper aims to review current researches on cold-formed steel connections, particularly for screw connections, storage rack connections, welded connections, and bolted connections. The performance of these connections in the design of cold-formed steel structures is discussed. PMID:24688448

  19. [Study on absorbing volatile oil with mesoporous carbon].

    PubMed

    Yan, Hong-mei; Jia, Xiao-bin; Zhang, Zhen-hai; Sun, E; Yang Nan

    2014-11-01

    Clove oil and turmeric oil were absorbed by mesoporous carbon. The absorption ratio of mesoporous carbon to volatile oil was optimized with the eugenol yield and curcumol yield as criteria Curing powder was characterized by scanning electron microscopy (SEM) and differential scanning calorietry (DSC). The effects of mesoporous carbon on dissolution in vitro and thermal stability of active components were studied. They reached high adsorption rate when the absorption ratio of mesoporous carbon to volatile oil was 1:1. When volatile oil was absorbed, dissolution rate of active components had a little improvement and their thermal stability improved after volatile oil was absorbed by the loss rate decreasing more than 50%. Absorbing herbal volatile oil with mesoporous carbon deserves further studying. PMID:25850263

  20. Overcoming the far-field diffraction limit via absorbance modulation

    E-print Network

    Tsai, Hsin-Yu Sidney

    2011-01-01

    Diffraction limits the resolution of far-field lithography and imaging to about half of the wavelength, which greatly limits the capability of optical techniques. The proposed technique with absorbance modulation aims to ...

  1. Multiband plasmonic absorber based on transverse phase resonances

    E-print Network

    Xu, Jun

    We demonstrate a multiband plasmonic absorber based on transverse phase resonances. We show that the modification of conventional metallic surfaces of T-shape grooves can cause mode splitting of the plasmonic waveguide ...

  2. Absorbed dose measurements during routine equine radiographic procedures 

    E-print Network

    Salinas, Leticia Lamar

    1996-01-01

    This study was performed in order to determine absorbed doses from scattered radiation to personnel during routine equine radiographic procedures and to determine if the protective apparel adequately reduced exposure from scattered radiation...

  3. Slow light in saturable absorbers Bruno Macke and Bernard Segard

    E-print Network

    Boyer, Edmond

    with the experiments recently achieved on doped crystals, biological samples, doped optical fibers and semiconductor heterostructures, we revisit the theory of the propagation of a pulse-modulated light in a saturable absorber

  4. 83. Shock absorber attaching "egg" to the launch control center, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    83. Shock absorber attaching "egg" to the launch control center, southwest corner - Ellsworth Air Force Base, Delta Flight, Launch Control Facility, County Road CS23A, North of Exit 127, Interior, Jackson County, SD

  5. 48. Bottom of shock absorber, bottom of launch tube, soda ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    48. Bottom of shock absorber, bottom of launch tube, soda bottle liter at right - Ellsworth Air Force Base, Delta Flight, Launch Facility, On County Road T512, south of Exit 116 off I-90, Interior, Jackson County, SD

  6. 14. Missile thrusters, missile resting on ring, shock absorber attachments ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    14. Missile thrusters, missile resting on ring, shock absorber attachments at three points - Ellsworth Air Force Base, Delta Flight, Launch Facility, On County Road T512, south of Exit 116 off I-90, Interior, Jackson County, SD

  7. 86. Shock absorber, top of launch control center, southeast corner ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    86. Shock absorber, top of launch control center, southeast corner - Ellsworth Air Force Base, Delta Flight, Launch Control Facility, County Road CS23A, North of Exit 127, Interior, Jackson County, SD

  8. Energy deposition studies for the LBNE beam absorber

    E-print Network

    Rakhno, Igor L; Tropin, Igor S

    2015-01-01

    Results of detailed Monte Carlo energy deposition studies performed for the LBNE absorber core and the surrounding shielding with the MARS15 code are described. The model of the entire facility, that includes a pion-production target, focusing horns, target chase, decay channel, hadron absorber system -- all with corresponding radiation shielding -- was developed using the recently implemented ROOT-based geometry option in the MARS15 code. This option provides substantial flexibility and automation when developing complex geometry models. Both normal operation and accidental conditions were studied. Various design options were considered, in particular the following: (i) filling the decay pipe with air or helium; (ii) the absorber mask material and shape; (iii) the beam spoiler material and size. Results of detailed thermal calculations with the ANSYS code helped to select the most viable absorber design options.

  9. The variability of warm absorbers in Active Galactic Nuclei

    E-print Network

    Gibson, Robert R. (Robert Ross)

    2006-01-01

    This thesis presents three studies of warm (photoionized) absorber variability in Active Galactic Nuclei (AGN) using high-resolution X-ray spectra provided by the Chandra High Energy Transmission Grating (HETG). The first ...

  10. Fixed point theory for compact absorbing contractive admissible type maps

    Microsoft Academic Search

    Ravi P. Agarwal; Donal ORegan

    2008-01-01

    In this article we present new Lefschetz fixed point theorems for compact absorbing contractive admissible maps between Fréchet spaces. Also, we discuss condensing maps with a compact attractor. Finally we present new antipodal fixed point theory for Kakutani maps.

  11. Diagnostic beam absorber in Mu2e beam line

    SciTech Connect

    Rakhno, Igor; /Fermilab

    2011-03-01

    Star density, hadron flux, and residual dose distributions are calculated around the {mu}2e diagnostic beam absorber. Corresponding surface and ground water activation, and air activation are presented as well.

  12. Liquid absorbent solutions for separating nitrogen from natural gas

    DOEpatents

    Friesen, Dwayne T. (Bend, OR); Babcock, Walter C. (Bend, OR); Edlund, David J. (Redmond, OR); Lyon, David K. (Bend, OR); Miller, Warren K. (Bend, OR)

    2000-01-01

    Nitrogen-absorbing and -desorbing compositions, novel ligands and transition metal complexes, and methods of using the same, which are useful for the selective separation of nitrogen from other gases, especially natural gas.

  13. Absorbed dose measurements during routine equine radiographic procedures

    E-print Network

    Salinas, Leticia Lamar

    1996-01-01

    This study was performed in order to determine absorbed doses from scattered radiation to personnel during routine equine radiographic procedures and to determine if the protective apparel adequately reduced exposure from scattered radiation...

  14. Sodium erosion of boron carbide from breached absorber pins

    SciTech Connect

    Basmajian, J.A.; Baker, D.E.

    1981-03-01

    The purpose of the irradiation experiment was to provide an engineering demonstration of the irradiation behavior of breached boron carbide absorber pins. By building defects into the cladding of prototypic absorber pins, and performing the irradiation under typical FFTF operating conditions, a qualitative assessment of the consequences of a breach was achieved. Additionally, a direct comparison of pin behavior with that of the ex-reactor test could be made.

  15. Light Absorbing Particle (LAP) Measurements in the Lower Stratosphere

    NASA Technical Reports Server (NTRS)

    Baumgardner, D.; Raga, G. B.; Anderson, B.; Diskin, G.; Sachse, G.; Kok, G.

    2003-01-01

    This viewgraph presentation covers the capabilities and design of the Single Particle Soot Photometer (SP-2), and reviews its role on the Sage III Ozone Loss Validation Experiment (SOLVE II) field campaign during 2003. On SOLVE II the SP-2 was carried into the Arctic onboard a DC-8 aircraft, in order to determine the size distribution of light-absorbing and non light-absorbing particles in the stratosphere. Graphs and tables relate some of the results from SOLVE II.

  16. Determining factors for high performance silicone rubber microwave absorbing materials

    Microsoft Academic Search

    Hua Zou; Shuhuan Li; Liqun Zhang; Shani Yan; Hanguang Wu; Shuai Zhang; Ming Tian

    2011-01-01

    Silicone rubber microwave absorbing materials (RMAMs) based on ferrite as the major absorbent were prepared by the mechanical blending method. The determining factors for the complex permittivity, complex permeability, and reflectivity of RMAM were thoroughly investigated with various samples including different crystal structures of Ba-ferrite (M-type, W-type, and Y-type), the ferrite with doped elements (Ba, Sr), the materials' thickness, the

  17. Advanced nuclear fuels corporation's achievements with gadolinia integral burnable absorbers

    Microsoft Academic Search

    F. B. Skogen; F. J. Kempf

    1988-01-01

    Advanced Nuclear Fuels Corporation (ANF) first introduced gadolinia integral burnable absorbers in pressurized water reactors (PWRs) a decade ago. The experience of ANF with gadolinia burnable absorbers include nearly 45,000 gadolinia-bearing fuel rods in â7500 assemblies irradiated in 29 reactors: 11 PWRs and 18 boiling water reactors. Predictable neutronic performance and excellent fuel integrity has been achieved by ANF in

  18. Observation of ?-ray spectra after penetrating absorbing materials

    Microsoft Academic Search

    Y. Kawada; T. Yamada; J. Itoh; Y. Sato; A. Yunoki; Y. Hino

    2008-01-01

    ?-Ray spectra after penetrating absorbing materials of various thicknesses were observed by the use of a scintillation-type ?-ray spectrometer equipped with a flat NE-102 plastic scintillator of 5mm thickness for sources of 60Co, 90Sr–90Y, 137Cs, 147Pm and 204Tl. Although the spectra changed rapidly with increasing absorber thickness, the average ?-ray energy was kept nearly constant for a wider range. These

  19. Picosecond flash photolysis apparatus with high absorbance resolution

    SciTech Connect

    Ebbesen, T.W.

    1988-08-01

    A new picosecond flash photolysis apparatus is described which makes extensive use of fiber optics in the probing beam pathway. The apparatus is simple and easy to use. The absorbance resolution and accuracy are greatly enhanced and allow for quantitative determination of properties of transient species. The capability of the system is illustrated by determining the excited singlet state absorbance properties of erythrosine and rose bengal.

  20. Calirimeter/absorber optimization for a RHIC dimuon experiment

    SciTech Connect

    Aronson, S.H.; Murtagh, M.J.; Starks, M. [Brookhaven National Lab., Upton, NY (United States); Liu, X.T.; Petitt, G.A.; Zhang, Z. [Georgia State Univ., Atlanta (United States); Ewell, L.A.; Hill, J.C.; Wohn, F.K. [Iowa State Univ., Ames (United States); Costales, J.B.; Namboodiri, M.N., Sangster, T.C.; Thomas, J.H. [Lawrence Livermore National Lab., CA (United States); Gavron, A.; Waters, L. [Los Alamos National Lab., NM (United States); Kehoe, W.L.; Steadman, S.G. [Massachusetts Institute of Technology, Cambridge (United States); Awes, T.C.; Obenshain, F.E.; Saini, S.; Young, G.R. [Oak Ridge National Lab., TN (United States); Chang, J.; Fung, S.Y.; Kang, J.H. [Univ. of California, Riverside, CA (United States); Kreke, J.; He, Xiaochun, Sorensen, S.P. [Univ. of Tennessee, Knoxville (United States); Cornell, E.C.; Maguire, C.F. [Vanderbilt Univ., Nashville, TN (United States)

    1991-12-31

    The RD-10 R&D effort on calorimeter/absorber optimization for a RHIC experiment had an extended run in 1991 using the A2 test beam at the AGS. Measurements were made of the leakage of particles behind various model hadron calorimeters. Behavior of the calorimeter/absorber as a muon-identifier was studied. First comparisons of results from test measurements to calculated results using the GHEISHA code were made

  1. Pharmacological Blockade of TRPM8 Ion Channels Alters Cold and Cold Pain Responses in Mice

    Microsoft Academic Search

    Wendy M. Knowlton; Richard L. Daniels; Radhika Palkar; Daniel D. McCoy; David D. McKemy; Gennady Cymbalyuk

    2011-01-01

    TRPM8 (Transient Receptor Potential Melastatin-8) is a cold- and menthol-gated ion channel necessary for the detection of cold temperatures in the mammalian peripheral nervous system. Functioning TRPM8 channels are required for behavioral responses to innocuous cool, noxious cold, injury-evoked cold hypersensitivity, cooling-mediated analgesia, and thermoregulation. Because of these various roles, the ability to pharmacologically manipulate TRPM8 function to alter the

  2. 40 CFR 63.990 - Absorbers, condensers, and carbon adsorbers used as control devices.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... false Absorbers, condensers, and carbon adsorbers used as control devices. ...63.990 Absorbers, condensers, and carbon adsorbers used as control devices. ...operators using absorbers, condensers, or carbon adsorbers to meet a...

  3. 40 CFR 63.990 - Absorbers, condensers, and carbon adsorbers used as control devices.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... false Absorbers, condensers, and carbon adsorbers used as control devices. ...63.990 Absorbers, condensers, and carbon adsorbers used as control devices. ...operators using absorbers, condensers, or carbon adsorbers to meet a...

  4. Investigations on laser transmission welding of absorber-free thermoplastics

    NASA Astrophysics Data System (ADS)

    Mamuschkin, Viktor; Olowinsky, Alexander; Britten, Simon W.; Engelmann, Christoph

    2014-03-01

    Within the plastic industry laser transmission welding ranks among the most important joining techniques and opens up new application areas continuously. So far, a big disadvantage of the process was the fact that the joining partners need different optical properties. Since thermoplastics are transparent for the radiation of conventional beam sources (800- 1100 nm) the absorbance of one of the joining partners has to be enhanced by adding an infrared absorber (IR-absorber). Until recently, welding of absorber-free parts has not been possible. New diode lasers provide a broad variety of wavelengths which allows exploiting intrinsic absorption bands of thermoplastics. The use of a proper wavelength in combination with special optics enables laser welding of two optically identical polymer parts without absorbers which can be utilized in a large number of applications primarily in the medical and food industry, where the use of absorbers usually entails costly and time-consuming authorization processes. In this paper some aspects of the process are considered as the influence of the focal position, which is crucial when both joining partners have equal optical properties. After a theoretical consideration, an evaluation is carried out based on welding trials with polycarbonate (PC). Further aspects such as gap bridging capability and the influence of thickness of the upper joining partner are investigated as well.

  5. Simulation of terahertz metamaterial absorbers with microbolometer structure

    NASA Astrophysics Data System (ADS)

    Ding, Jie; Wang, Jun; Guo, Xiaopei; Jiang, Yadong; Fan, Lin

    2014-09-01

    The metamaterial absorber in terahertz (THz) region, with the metal pattern layer/dielectric spacer/metal reflective layer sandwich structure, is characterized in this paper. The principle of metamaterial absorber absorbing terahertz wave was introduced firstly. The top layer of metamaterial absorber is a periodically patterned with metallic subwavelength structure, which also serves as an electric resonator. The bottom layer is a thick metal plane, which is used to reduce THz wave transmittance. The dielectric layer between two metallic layers results in magnetic resonance and the resonance depends on the thickness and dielectric constant of the dielectric layer. The absorption of metamaterial absorber to terahertz wave was simulated with CST software. The relationship between the size of the metamaterial structure and absorption frequency was analyzed with the simulation results. The results indicate that the absorption frequency is affected by the cell constant and geometric structure of top metal pattern, and absorption rate is related to both the thickness of dielectric layer and the size of resonator. In the end, the possibility of integrating the metamaterial absorber with micro-bridge structure to design room temperature terahertz detector was discussed, and the manufacturing process was introduced about room temperature terahertz detector with high THz wave absorption rate.

  6. Newly developed broadband plasmonic absorber for uncooled infrared detectors

    NASA Astrophysics Data System (ADS)

    Park, Hae-Seok; Nam, Sung Hyun; Hong, Hyun-Gue; Roh, Sookyoung; Yun, Seokho; Kim, JungWoo; Kwon, Dongil; Chung, U.-In

    2014-03-01

    In this paper, we introduce a floating plasmonic absorber having multiple resonances in the 8 ~ 14 ?m spectral range and broadband absorption characteristics by adjusting Drude relaxation rate of metal. This plasmonic broadband resonator capable of capturing light with a large optical cross-section area is able to substantially enhance the performance of micro-bolometer (response time, noise equivalent temperature difference, pixel size and so on) due to the significantly reduced thermal mass and conductance. Firstly, to adjust Drude relaxation rate, the mean crystalline size of metal was optimized by changing the deposition condition and the absorption characteristics of absorber were measured by Fourier transform infrared spectroscopy in the 8 ~ 14 ?m spectral range. The measurement results show that 1.62 times of broadening in bandwidth was obtained by decreasing the crystalline size from 5.73 nm to 3.18 nm while maintaining the maximum absorption at resonant wavelength of 10 ?m within 93 ~ 95%. Comparisons between measurements and CST microwave studio simulations show similar spectral absorption trends. And then, to integrate plasmonic absorber with micro-bolometer, various kinds of plasmonic absorbers which have combinations of short and long dipole resonators were designed and simulated. Based on these results, 12 ?m micro-bolometer pixels integrated with plasmonic broadband Ti absorber are designed and fabricated. The optimized Ti resonators with multiple resonance and small crystalline size absorb 88 % of the unpolarized radiation in the 8 ~ 14 ?m spectral range on the average.

  7. Direct MC conversion of absorbed dose to graphite to absorbed dose to water for 60Co radiation.

    PubMed

    Lye, J E; Butler, D J; Franich, R D; Harty, P D; Oliver, C P; Ramanathan, G; Webb, D V; Wright, T

    2013-06-01

    The ARPANSA calibration service for (60)Co gamma rays is based on a primary standard graphite calorimeter that measures absorbed dose to graphite. Measurements with the calorimeter are converted to the absorbed dose to water using the calculation of the ratio of the absorbed dose in the calorimeter to the absorbed dose in a water phantom. ARPANSA has recently changed the basis of this calculation from a photon fluence scaling method to a direct Monte Carlo (MC) calculation. The MC conversion uses an EGSnrc model of the cobalt source that has been validated against water tank and graphite phantom measurements, a step that is required to quantify uncertainties in the underlying interaction coefficients in the MC code. A comparison with the Bureau International des Poids et Mesures (BIPM) as part of the key comparison BIPM.RI(I)-K4 showed an agreement of 0.9973 (53). PMID:23152147

  8. Blepharoplasty: laser or cold steel?

    PubMed

    Biesman, B S

    2003-01-01

    Blepharoplasty of the upper and/or lower eyelids can restore a youthful appearance to the aging face. This is a minimally invasive procedure that can be accomplished with little bleeding and a small incision. Laser-assisted blepharoplasty was pioneered in 1980, with the technique simplified after the subsequent introduction of the pulsed carbon dioxide laser. Laser-assistance helps mitigate bleeding during blepharoplasty. In ideal circumstances, the laser can be used as a multipurpose device that simultaneously offers cutting, cautery and blunt dissection capabilities. However, there is little experimental evidence confirming the superiority of laser-assisted blepharoplasty over more traditional scalpel surgery. For some procedures cold-steel may be preferable, and some surgeons prefer to use a knife for initial incisions and then laser for its coagulative properties. Patient factors and physician skill should guide the selection of the ideal blepharoplasty technique. PMID:14610612

  9. Atomic Platters: Cold War Music

    NSDL National Science Digital Library

    Along with ushering in a new age of global unrest and high anxiety, the emergence of the atomic bomb had a curious and not totally unpredictable effect on the world of popular (and not-so-popular) music. This site brings together these various subgenres of "atomic" music in a way that's rather fun, intriguing, and at times, a bit scary. Visitors can look through such subgenres as "Atomic", "Cold War", "Flying Saucer", and so on. While most of the songs are not available in their full form, visitors can read all of the lyrics and interpretive essays. Of course, visitors can find plenty of audio joy at the "CONELRAD Audio Archives" area. Herein are contained such gems as the positively odd "The Complacent Americans" and the equally lovable novelty album "The Goldwaters Sing Folk Songs to Bug the Liberals".

  10. Status of cold fusion (2010)

    NASA Astrophysics Data System (ADS)

    Storms, Edmund

    2010-10-01

    The phenomenon called cold fusion has been studied for the last 21 years since its discovery by Profs. Fleischmann and Pons in 1989. The discovery was met with considerable skepticism, but supporting evidence has accumulated, plausible theories have been suggested, and research is continuing in at least eight countries. This paper provides a brief overview of the major discoveries and some of the attempts at an explanation. The evidence supports the claim that a nuclear reaction between deuterons to produce helium can occur in special materials without application of high energy. This reaction is found to produce clean energy at potentially useful levels without the harmful byproducts normally associated with a nuclear process. Various requirements of a model are examined.

  11. Cold Chain Equipment Planning with CCEM

    E-print Network

    Anderson, Richard

    equipment manager ­ FoneAstra: Temperature monitoring ­ SmartConnect: Data communication ­ Cell Phones with the idea that an equipment inventory and planning tool would support systematic management of the coldCold Chain Equipment Planning with CCEM Richard Anderson, Sophie Newland, John Lloyd, David

  12. Cold Chain Equipment Planning with CCEM

    E-print Network

    Anderson, Richard

    equipment manager ­FoneAstra: Temperature monitoring ­SmartConnect: Data communication ­Cell Phones for TB that an equipment inventory and planning tool would support systematic management of the cold chain. (Dr. Fernando12/9/2010 1 Cold Chain Equipment Planning with CCEM Richard Anderson, Sophie Newland, John Lloyd

  13. Gauss Sum Factorization with Cold Atoms

    SciTech Connect

    Gilowski, M.; Wendrich, T.; Mueller, T.; Ertmer, W.; Rasel, E. M. [Institut fuer Quantenoptik, Leibniz Universitaet Hannover, Welfengarten 1, D-30167 Hannover (Germany); Jentsch, Ch. [Astrium GmbH-Satellites, 88039 Friedrichshafen (Germany); Schleich, W. P. [Institut fuer Quantenphysik, Universitaet Ulm, Albert-Einstein-Allee 11, D-89081 Ulm (Germany)

    2008-01-25

    We report the first implementation of a Gauss sum factorization algorithm by an internal state Ramsey interferometer using cold atoms. A sequence of appropriately designed light pulses interacts with an ensemble of cold rubidium atoms. The final population in the involved atomic levels determines a Gauss sum. With this technique we factor the number N=263193.

  14. Real-Time Cold Chain Mapping

    Microsoft Academic Search

    Allen Higgins; Stefan Klein; Stefan Reidy; Fred Barrett; Nils Johanning

    This paper presents an investigation of the application of autonomous telemetry sensors for real-time cold-chain mapping and shipment management of temperature sensitive product. New developments in electronic cold chain management pose challenges to organisations and how they engage in inter- organisational interactions. Advanced sensors and wireless monitoring enable the capture of multiple parameters such as temperature and location. A configuration

  15. Global climate change: Cold region ecosystems

    SciTech Connect

    Lal, R.; Eswaran, H.; Kimble, J.M.; Stewart, B.A. [eds.

    2000-07-01

    This book provides information on soil processes and the carbon cycle in cold ecoregions. The editors have chosen papers that cover: soil carbon pools in different ecoregions, the impact of natural and anthropogenic disturbances on soil carbon pools, the method of assessment of carbon and other properties of soils of the cold ecoregions.

  16. Casualties and Injuries Chart Cold Weather

    E-print Network

    Maxwell, Bruce D.

    adequate hydration and ensure nutritional requirements are met * POL - petoleum, oil, lubricants See http in the Cold Weather environment: Chilblain Cause l Repeated exposure of bare skin for prolonged periods from 20°- 60°F with high humidity (for those not acclimated to cold weather). Symptoms l Swollen, red skin

  17. Cold Spring Harbor Asia High Throughput Biology

    E-print Network

    Smith, Adam D.

    Cold Spring Harbor Asia High Throughput Biology Suzhou, China April 19 - 23, 2011 Arranged by to announce the inaugural Cold Spring Harbor Asia conference on High Throughput Biology which will be held at the Suzhou Dushu Lake Conference Center in Suzhou, China. The conference will begin at 7:30pm on the evening

  18. Cold spray deposition of thermoplastic powder

    Microsoft Academic Search

    Y. Xu; I. M. Hutchings

    2006-01-01

    The cold spray deposition of polyolefin powder has been investigated, at substantially lower velocities (up to ?135 m s?1) than those used in the cold gas dynamic spray (CGDS) process for metals. The particles were accelerated at room temperature in air through a cylindrical nozzle, and were deposited on to polyethylene and aluminium substrates. Fully-dense deposits were formed at temperatures substantially

  19. Preserving Alaska's early Cold War legacy

    Microsoft Academic Search

    J. Hoffecker; M. Whorton

    1999-01-01

    The US Air Force owns and operates numerous facilities that were constructed during the Cold War era. The end of the Cold War prompted many changes in the operation of these properties: missions changed, facilities were modified, and entire bases were closed or realigned. The widespread downsizing of the US military stimulated concern over the potential loss of properties that

  20. Extreme Cold Weather Warning Recent subzero wind chill temperatures have understandably brought cold stress to a heighten

    E-print Network

    Cantlon, Jessica F.

    winds, or wet clothing. THE COLD STRESS EQUATION U.S. Department of Labor Occupational Safety and Health cold stress to a heighten awareness. The plummeting temperatures mandate that we take extra precautions. Workers who are exposed to extreme cold or work in cold environments may be at risk of cold stress

  1. Maintaining the cold chain for vaccines.

    PubMed

    Petrovi?, Vladimir; Seguljev, Zorica; Gajin, Branka

    2005-01-01

    Cold chain for vaccines a is a system for storing and transporting vaccines at very low temperatures to maintain their effectiveness before use. Because vaccines are sensitive biological substances, their exposition to high temperatures directly affects the quality of vaccines and safety of immunization. The goal of this study was to assess the safety of cold chain for vaccines within the cold chain system in two services of Health Center Novi Sad. Cold Chain Monitors (CCM) and Freeze Watch (FW) indicators were used. A total of 155 (94.5%) Cold Chain Monitors (CCM) and 100 (95.2%) Freeze Watch (FW) indicators were analyzed. Only one CCM showed a breack in cold chain. A total of 3 CCMs indicated risk of vaccine wastage. A total of 9 CCMs were colorized without risk of vaccine wastage. FWs were positive in a high percentage in both services of Health Center Novi Sad. FWs were exposed to low temperatures during transport. Statistically significant differencies in the number of exposed CCMs to high temperatures and the number of exposed FWs to low temperatures were observed in these two services. A statistically significant difference in number of FWs exposed to low temperatures was observed in regard to the period of transport and the period of storage at the vaccination stations. The study shows high level of safety of the cold chain in two services of Health Center Novi Sad Cold Chain Monitor is a reliable indicator of the quality of cold chain for vaccines. Freeze Watch is a reliable indicator of the quality of cold chain during storage of vaccines, but not during their transport. PMID:16296574

  2. 7 CFR 305.16 - Cold treatment schedules.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...2010-01-01 2010-01-01 false Cold treatment schedules. 305.16 Section 305.16...DEPARTMENT OF AGRICULTURE PHYTOSANITARY TREATMENTS Cold Treatments § 305.16 Cold treatment schedules. Treatment schedule...

  3. ConcepTest: Hot/Cold Water Circulation

    NSDL National Science Digital Library

    A fish tank is filled almost to the brim with room temperature water. Two containers of cold and hot water are prepared. Red coloring is added to the hot water, blue coloring is added to the cold water. The cold ...

  4. Photodetector with absorbing region having resonant periodic absorption between reflectors

    DOEpatents

    Bryan, Robert P. (Boulder, CO); Olbright, Gregory R. (Boulder, CO); Brennan, Thomas M. (Albuquerque, NM); Tsao, Jeffrey Y. (Albuquerque, NM)

    1995-02-14

    A photodetector that is responsive to a wavelength or wavelengths of interest which have heretofore been unrealized. The photodetector includes a resonant cavity structure bounded by first and second reflectors, the resonant cavity structure being resonant at the wavelength or wavelengths of interest for containing a plurality of standing waves therein. The photodetector further includes a radiation absorbing region disposed within the resonant cavity structure, the radiation absorbing region including a plurality of radiation absorbing layers spaced apart from one another by a distance substantially equal to a distance between antinodes of adjacent ones of the standing waves. Each of radiation absorbing layers is spatially positioned at a location of one of the antinodes of one of the standing waves such that radiation absorption is enhanced. The radiation absorbing layers may be either bulk layers or quantum wells includes a plurality of layers, each of which is comprised of a strained layer of InGaAs. Individual ones of the InGaAs layers are spaced apart from one another by a GaAs barrier layer.

  5. The Equilibrium Photoionized Absorber in 3C351

    E-print Network

    Nicastro, F; Elvis, M; Perola, G C

    1999-01-01

    We present two ROSAT PSPC observations of the radio-loud, lobe-dominated quasar 3C 351, which shows an `ionized absorber' in its X-ray spectrum. The factor 1.7 change in flux in the $\\sim$2~years between the observations allows a test of models for this ionized absorber. The absorption feature at ~0.7 keV (quasar frame) is present in both spectra but with a lower optical depth when the source intensity - and hence the ionizing flux at the absorber - is higher, in accordance with a simple, single-zone, equilibrium photoionization model. Detailed modeling confirms this agrement quantitatively. The maximum response time of 2 years allows us to limit the gas density: n_e > 2 x 10^4 cm^{-3}; and the distance of the ionized gas from the central source R < 19 pc. This produces a strong test for a photoionized absorber in 3C~351: a factor 2 flux change in ~1 week in this source must show non-equilibrium effects in the ionized absorber.

  6. The Equilibrium Photoionized Absorber in 3C351

    E-print Network

    F. Nicastro; F. Fiore; M. Elvis; G. C. Perola

    1998-09-09

    We present two ROSAT PSPC observations of the radio-loud, lobe-dominated quasar 3C 351, which shows an `ionized absorber' in its X-ray spectrum. The factor 1.7 change in flux in the $\\sim$2~years between the observations allows a test of models for this ionized absorber. The absorption feature at ~0.7 keV (quasar frame) is present in both spectra but with a lower optical depth when the source intensity - and hence the ionizing flux at the absorber - is higher, in accordance with a simple, single-zone, equilibrium photoionization model. Detailed modeling confirms this agrement quantitatively. The maximum response time of 2 years allows us to limit the gas density: n_e > 2 x 10^4 cm^{-3}; and the distance of the ionized gas from the central source R < 19 pc. This produces a strong test for a photoionized absorber in 3C~351: a factor 2 flux change in ~1 week in this source must show non-equilibrium effects in the ionized absorber.

  7. The Equilibrium Photoionized Absorber in 3C 351

    NASA Astrophysics Data System (ADS)

    Nicastro, Fabrizio; Fiore, Fabrizio; Perola, G. Cesare; Elvis, Martin

    1999-02-01

    We present two ROSAT Position Sensitive Proportional Counter (PSPC) observations of the radio-loud, lobe-dominated quasar 3C 351, which shows an ``ionized absorber'' in its X-ray spectrum. The factor of 1.7 change in flux in the ~2 years between the observations allows a test of models for this ionized absorber. The absorption feature at ~0.7 keV (quasar frame) is present in both spectra but with a lower optical depth when the source intensity--and hence the ionizing flux at the absorber--is higher, in accordance with a simple, single-zone, equilibrium photoionization model. Detailed modeling confirms this agreement quantitatively. The maximum response time of 2 years allows us to limit the gas density: ne>2×104 cm-3 and the distance R of the ionized gas from the central source is less than 19 pc. This produces a strong test for a photoionized absorber in 3C 351: a factor of 2 flux change in ~1 week in this source must show nonequilibrium effects in the ionized absorber.

  8. Plasmon Enhanced Ultrathin Film Broad-Band Nanoporous Absorber

    NASA Astrophysics Data System (ADS)

    Lu, Jin-You; Liu, Dong; Wilke, Kyle; Noorulla, Sumaya; Fang, Nicholas; Zhang, Tiejun

    2015-03-01

    Ultrathin absorbing films have attracted much attention due to their strong interference persisted inside the lossy dielectric film, which has much smaller thickness compared with conventional resonators. The absorber was realized by coating a lossy dielectric film with tens of nanometers in thickness on a metallic substrate. The ultrathin absorber was further developed to obtain perfect absorption at a given wavelength by inserting a spacer TiO2 between the dielectric and metallic substrate. However, this interference mode just contributes to the narrow band absorption. Here, we propose to combine the strong interference inside the ultrathin film absorber with localized surface plasmons (LSPs) to achieve broad-band absorption. This concept is realized by coating ultrathin absorbing Ge/Au films on nanoporous substrate, where the LSP mode is supported by pore-shape cavities. The near-field optical properties of ultrathin film on nanoporous substrate are analyzed by using the finite difference time domain method to study the spectroscopy and energy flow patterns. Simulation shows the absorption increases with the pore radius until the pore is too large to sustain LSP. Light is trapped in nanopores and penetrated into the lossy dielectric film around the pore entrance. Supported by cooperative agreement between Masdar Inst and MIT.

  9. Photodetector with absorbing region having resonant periodic absorption between reflectors

    DOEpatents

    Bryan, R.P.; Olbright, G.R.; Brennan, T.M.; Tsao, J.Y.

    1995-02-14

    A photodetector is disclosed that is responsive to a wavelength or wavelengths of interest which have heretofore been unrealized. The photodetector includes a resonant cavity structure bounded by first and second reflectors, the resonant cavity structure being resonant at the wavelength or wavelengths of interest for containing a plurality of standing waves therein. The photodetector further includes a radiation absorbing region disposed within the resonant cavity structure, the radiation absorbing region including a plurality of radiation absorbing layers spaced apart from one another by a distance substantially equal to a distance between antinodes of adjacent ones of the standing waves. Each of radiation absorbing layers is spatially positioned at a location of one of the antinodes of one of the standing waves such that radiation absorption is enhanced. The radiation absorbing layers may be either bulk layers or quantum wells includes a plurality of layers, each of which is comprised of a strained layer of InGaAs. Individual ones of the InGaAs layers are spaced apart from one another by a GaAs barrier layer. 11 figs.

  10. Measurements of Light Absorbing Particles on Tropical South American Glaciers

    NASA Astrophysics Data System (ADS)

    Schmitt, C. G.; All, J.; Schwarz, J. P.; Arnott, W. P.; Warthon, J.; Andrade, M.; Celestian, A. J.; Hoffmann, D.; Cole, R. J.; Lapham, E.; Horodyskyj, U. N.; Froyd, K. D.; Liao, J.

    2014-12-01

    Glaciers in the tropical Andes have been losing mass rapidly in recent decades. In addition to the documented increase in temperature, increases in light absorbing particulates deposited on glaciers could be contributing to the observed glacier loss. Here we present results of measurements of light absorbing particles from glaciers in Peru and Bolivia. Samples have been collected by American Climber Science Program volunteers and scientists at altitudes up to 6770 meters. Collected snow samples were melted and filtered in the field. A new inexpensive technique, the Light Absorption Heating Method (LAHM) has been developed for analysis of light absorbing particles collected on filters. Results from LAHM analysis are calibrated using filters with known amounts of fullerene soot, a common industrial surrogate for black carbon (BC). For snow samples collected at the same field location LAHM analysis and measurements from the Single Particle Soot Photometer (SP2) instrument are well correlated (r2 = 0.92). Co-located SP2 and LAHM filter analysis suggest that BC could be the dominant absorbing component of the light absorbing particles in some areas.

  11. Calorimetry at 10. 6. mu. m using organic volume absorbers

    SciTech Connect

    Sollid, J.E.; Bjork, C.W.

    1981-01-01

    Copper-Kapton laminate foils will be utilized as isoperibol calorimeters for pulsed energy measurements at Antares with apertures up to 1.5 m. These are volume absorbing calorimeters in which the radiation is absorbed in a layer tens of wavelengths thick, thereby reducing surface temperature and increasing damage threshold as compared to surface absorbing calorimeters. Kapton was chosen for its high absorption coefficient, 330 cm/sup -1/ at P(20) in the 10 ..mu..m band of CO/sub 2/, and its useful short pulse damage threshold, 2.8 J/cm/sup 2/. The copper backing integrates the absorbed heat pulse. The resultant temperature pulse is sensed by Type E thermocouples (chromel-constantan) soldered to the copper. Time vs voltage traces of the thermocouples can then be analyzed to obtain the energy absorbed. Calorimeters can be fabricated to virtually any size or shape, using photo-lithographic techniques. Utilizing single elements or several in a thermopile further expands the versatility of this technique.

  12. Inferring Absorbing Organic Carbon Content from AERONET Data

    NASA Technical Reports Server (NTRS)

    Arola, A.; Schuster, G.; Myhre, G.; Kazadzis, S.; Dey, S.; Tripathi, S. N.

    2011-01-01

    Black carbon, light-absorbing organic carbon (often called brown carbon) and mineral dust are the major light-absorbing aerosols. Currently the sources and formation of brown carbon aerosol in particular are not well understood. In this study we estimated globally the amount of light absorbing organic carbon and black carbon from AERONET measurements. We find that the columnar absorbing organic carbon (brown carbon) levels in biomass burning regions of South-America and Africa are relatively high (about 15-20 magnesium per square meters during biomass burning season), while the concentrations are significantly lower in urban areas in US and Europe. However, we estimated significant absorbing organic carbon amounts from the data of megacities of newly industrialized countries, particularly in India and China, showing also clear seasonality with peak values up to 30-35 magnesium per square meters during the coldest season, likely caused by the coal and biofuel burning used for heating. We also compared our retrievals with the modeled organic carbon by global Oslo CTM for several sites. Model values are higher in biomass burning regions than AERONET-based retrievals, while opposite is true in urban areas in India and China.

  13. Systematic review of absorbable vs non-absorbable sutures used for the closure of surgical incisions

    PubMed Central

    Sajid, Muhammad S; McFall, Malcolm R; Whitehouse, Pauline A; Sains, Parv S

    2014-01-01

    AIM: To report a systematic review of published randomized controlled trials (RCTs) investigating the role of absorbable suture (AS) against non-AS (NAS) used for the closure of surgical incisions. METHODS: RCTs investigating the use of AS vs NAS for the closure of surgical incisions were statistically analysed based upon the principles of meta-analysis and the summated outcomes were represented as OR. RESULTS: The systematic search of medical literature yielded 10 RCTs on 1354 patients. Prevalence of wound infection (OR = 0.97; 95%CI: 0.56, 1.69; Z = 0.11; P = 0.92) and operative morbidity (P = 0.45) was comparable in both groups. Nonetheless, the use of AS lead to lower risk of wound break-down (OR = 0.12; 95%CI: 0.04, 0.39; Z = 3.52; P < 0.0004). CONCLUSION: This meta-analysis of 10 RCTs demonstrates that the use of AS is similar to NAS for skin closure for surgical site infection and other operative morbidities. AS do not increase the risk of skin wound dehiscence, rather lead to a reduced risk of wound dehiscence compared to NAS. PMID:25548609

  14. Ultra-cold Atom CollisionsUltra-cold Atom Collisions and Quantum Dynamics atand Quantum Dynamics at

    E-print Network

    Band, Yehuda B.

    Ultra-cold Atom CollisionsUltra-cold Atom Collisions and Quantum Dynamics atand Quantum Dynamics are available at Ben-Gurion University to carry out research in ultra-cold atomic and molecular physics

  15. The Effects of Cold Acclimation on Photosynthetic Apparatus and the Expression of COR14b in Four Genotypes of Barley (Hordeum vulgare) Contrasting in their Tolerance to Freezing and High-light Treatment in Cold Conditions

    PubMed Central

    Rapacz, Marcin; Wolanin, Barbara; Hura, Katarzyna; Tyrka, Miros?aw

    2008-01-01

    Background and Aims Cold acclimation modifies the balance of the energy absorbed and metabolized in the dark processes of photosynthesis, which may affect the expression of cold-regulated (COR) genes. At the same time, a gradual acclimation to the relatively high light conditions is observed, thereby minimizing the potential for photo-oxidative damage. As a result, the resistance to photoinhibition in the cold has often been identified as a trait closely related to freezing tolerance. Using four barley genotypes that differentially express both traits, the effect of cold acclimation on freezing tolerance and high-light tolerance was studied together with the expression of COR14b, one of the best-characterized barley COR genes. Methods Plants were cold acclimated for 2 weeks at 2 °C. Freezing tolerance was studied by means of electrolyte leakage. Changes in photosynthetic apparatus and high-light tolerance were monitored by means of chlorophyll fluorescence. Accumulation of COR14b and some proteins important in photosynthetic acclimation to cold were studied with western analysis. COR14b transcript accumulation during cold acclimation was assessed with real-time PCR. Key Results Cold acclimation increased both freezing tolerance and high-light tolerance, especially when plants were treated with high light after non-lethal freezing. In all plants, cold acclimation triggered the increase in photosynthetic capacity during high-light treatment. In two plants that were characterized by higher high-light tolerance but lower freezing tolerance, higher accumulation of COR14b transcript and protein was observed after 7 d and 14 d of cold acclimation, while a higher transient induction of COR14b expression was observed in freezing-tolerant plants during the first day of cold acclimation. High-light tolerant plants were also characterized with a higher level of PsbS accumulation and more efficient dissipation of excess light energy. Conclusions Accumulation of COR14b in barley seems to be important for resistance to combined freezing and high-light tolerance, but not for freezing tolerance per se. PMID:18245808

  16. Neutron absorbed dose determination by calculations of recoil energy.

    PubMed

    Wrobel, F; Benabdesselam, M; Iacconi, P; Lapraz, D

    2004-01-01

    The aim of this work is to calculate the absorbed dose to matter due to neutrons in the 5-150 MeV energy range. Materials involved in the calculations are Al2O3, CaSO4 and CaS, which may be used as dosemeters and have already been studied for their luminescent properties. The absorbed dose is assumed to be mainly due to the energy deposited by the recoils. Elastic reactions are treated with the ECIS code while for the non-elastic ones, a Monte Carlo code has been developed and allowed to follow the nucleus decay and to determine its characteristics (nature and energy). Finally, the calculations show that the absorbed dose is mainly due to non-elastic process and that above 20 MeV this dose decreases slightly with the neutron energy. PMID:15353750

  17. The small intestine can both absorb and glucuronidate luminal flavonoids.

    PubMed

    Spencer, J P; Chowrimootoo, G; Choudhury, R; Debnam, E S; Srai, S K; Rice-Evans, C

    1999-09-17

    We have studied the perfusion of the jejunum and ileum in an isolated rat intestine model with flavonoids and hydroxycinnamates and the influence of glycosylation on the subsequent metabolism. Flavone and flavonol glucosides and their corresponding aglycones are glucuronidated during transfer across the rat jejunum and ileum and this glucuronidation occurs without the need for gut microflora. Furthermore, this suggests the presence of glycosidases as well as UDP-glucuronyl transferase in the jejunum. In contrast, quercetin-3-glucoside and rutin are mainly absorbed unmetabolised. The results suggest that the more highly reducing phenolics are absorbed predominantly as glucuronides (96.5%+/-4.6) of the amount absorbed, whereas monophenolic hydroxycinnamates and monophenolic B-ring flavonoids are less predisposed to glucuronidation and higher levels of aglycone (88.1%+/-10.1) are detected on absorption through both the jejunum and ileum. PMID:10481070

  18. Infrared Imaging Video Bolometer with a Double Layer Absorbing Foil

    NASA Astrophysics Data System (ADS)

    Miroshnikov, Igor V.; Kostryukov, Artem Y.; Peterson, Byron J.

    The object of the present paper is an infrared video bolometer with a bolometer foil consisting of two layers: the first layer is constructed of radiation absorbing blocks and the second layer is a thermal isolating base. The absorbing blocks made of a material with a high photon attenuation coefficient (gold) were spatially separated from each other while the base should be made of a material having high tensile strength and low thermal conductance (stainless steel). Such a foil has been manufactured in St. Petersburg and calibrated in NIFS using a vacuum test chamber and a laser beam as an incident power source. A finite element method (FEM) code was applied to simulate the thermal response of the foil. Simulation results are in good agreement with the experimental calibration data. The temperature response of the double layer foil is a factor of two higher than that of a single foil IR video bolometer using the same absorber material and thickness.

  19. The HI Environment of Nearby Lyman-alpha Absorbers

    NASA Technical Reports Server (NTRS)

    VanGorkom, J. H.; Carilli, C. L.; Stocke, John T.; Perlman, Eric S.; Shull, J. Michael

    1996-01-01

    We present the results of a VLA and WSRT search for H I emission from the vicinity of seven nearby clouds, which were observed in Ly-alpha absorption with HST toward Mrk 335, Mrk 501, and PKS 2155-304. Around the absorbers, we searched a volume of 4O' x 40' x 1000 km/s; for one of the absorbers we probed a velocity range of only 600 km/s. The H I mass sensitivity (5 sigma) very close to the lines of sight varies from 5 x 10(exp 6) solar mass at best to 5 x 10(exp 8) solar mass at worst. We detected H I emission in the vicinity of four out of seven absorbers. The closest galaxy we find to the absorbers is a small dwarf galaxy at a projected distance of 68 h(exp -1) kpc from the sight line toward Mrk 335. This optically uncataloged galaxy has the same velocity (V = 1970 km/s) as one of the absorbers, is fainter than the SMC, and has an H I mass of only 4 x 10(exp 7) solar mass. We found a somewhat more luminous galaxy at exactly the velocity (V = 5100 km/s) of one of the absorbers toward PKS 2155-304 at a projected distance of 230 h(exp -1) kpc from the sight line. Two other, stronger absorbers toward PKS 2155-304 at V approx. 17,000 km/s appear to be associated with a loose group of three bright spiral galaxies, at projected distances of 300 to 600 h(exp -1) kpc. These results support the conclusions emerging from optical searches that most nearby Ly-alpha forest clouds trace the large-scale structures outlined by the optically luminous galaxies, although this is still based on small-number statistics. We do not find any evidence from the H I distribution or kinematics that there is a physical association between an absorber and its closest galaxy. While the absorbing clouds are at the systemic velocity of the galaxies, the H I extent of the galaxies is fairly typical, and at least an order of magnitude smaller than the projected distance to the sight line at which the absorbers are seen. On the other hand, we also do not find evidence against such a connection. In total, we detected H I emission from five galaxies, of which two were previously uncataloged and one did not have a known redshift. No H I emission was detected from the vicinity of the two absorbers, which are located in a void and a region of very low galaxy density; but the limits are somewhat less stringent than for the other sight lines. These results are similar to what has been found in optically unbiased H I surveys. Thus, presence of Ly-alpha absorbers does not significantly alter the H I detection rate in their environment.

  20. Photoexcited broadband blueshift tunable perfect terahertz metamaterial absorber

    NASA Astrophysics Data System (ADS)

    Xu, Zong-Cheng; Gao, Run-Mei; Ding, Chun-Feng; Wu, Liang; Zhang, Ya-Ting; Yao, Jian-Quan

    2015-04-01

    We present an demonstration of optically tunable metamaterial absorber at terahertz frequencies. The metamaterials are based on two split ring resonators (SSRs) that can be tuned by integrating photoconductive silicon into the metamaterial unit cell. Filing the gap between the resonator arm with a semiconductor (silicon), leads to easy modification of its optical response through a pump beam which changes conductivity of Si. The conductivity of silicon is a function of incident pump power. Therefore, the conductivity of silicon is tuned effectively by applying an external pump power. We demonstrate that a blueshift of the resonance frequency under illumination can be accomplished and a broadband switch of absorption frequencies varying from 0.68 to 1.41 THz, with a tuning range of 51.8%. The realization of broadband blueshift tunable metamaterial absorber offers opportunities for achieving switchable metamaterial absorber and could be implemented in terahertz devices to achieve additional functionalities.

  1. The precipitation synthesis of broad-spectrum UV absorber nanoceria

    SciTech Connect

    Nurhasanah, Iis; Sutanto, Heri; Puspaningrum, Nurul Wahyu [Department of Physics, Faculty of Science and Mathematics, Universitas Diponegoro Jl. Prof. Soedarto, S.H, Tembalang Semarang 50275 (Indonesia)] [Department of Physics, Faculty of Science and Mathematics, Universitas Diponegoro Jl. Prof. Soedarto, S.H, Tembalang Semarang 50275 (Indonesia)

    2013-09-09

    In this paper the possibility of nanoceria as broad-spectrum UV absorber was evaluated. Nanoceria were synthesized by precipitation process from cerium nitrate solution and ammonium hydroxide as precipitant agent. Isopropanol was mixed with water as solvent to prevent hard agglomeration. The structure of resulting nanoceria was characterized by x-ray diffractometer (XRD). The transparency in the visible light and efficiency of protection in UV A region were studied using ultraviolet-visible (UV - Vis) spectrophotometer. The results show that nanoceria possess good tranparency in visible light and high UV light absorption. The critical absorption wavelenght of 368 nm was obtained which is desirable for excellent broad-spectrum protection absorbers. Moreover, analysis of photodegradation nanoceria to methylene blue solution shows poor photocatalytic activity. It indicates that nanoceria suitable for used as UV absorber in personal care products.

  2. Fabrication and microwave absorbing properties of NixPy nanotubes

    NASA Astrophysics Data System (ADS)

    Wang, Haoran; Wan, Lei; Chen, Yaqiong; Hu, Wenbin; Liu, Lei; Zhong, Cheng; Deng, Yida

    2015-06-01

    Materials possessing microwave absorbing properties have been a researching hotspot for their important applications amid a high frequency electromagnetic waves environment. This paper focuses on the preparation of a series of NixPy(x:y = 2.65–2.73) nanotubes (NTs) and their corresponding microwave absorbing properties. After being heat-treated, different NixPy phases would appear, without damaging their initial hollow morphologies. These processes were accompanied with the alteration of related physical properties. Low enough minimum reflection loss (RL) has been achieved in all of these samples, with??48.63?dB as the lowest one being obtained at the non-heat-treated sample. Besides, a large proportion of the microwave frequency band could be covered on the 450?°C heat-treated sample (over a 4.5?GHz bandwidth). These are indicative of the superior microwave absorbing nature of NixPy NTs.

  3. Engineering Cold Stress Tolerance in Crop Plants

    PubMed Central

    Sanghera, Gulzar S; Wani, Shabir H; Hussain, Wasim; Singh, N.B

    2011-01-01

    Plants respond with changes in their pattern of gene expression and protein products when exposed to low temperatures. Thus ability to adapt has an impact on the distribution and survival of the plant, and on crop yields. Many species of tropical or subtropical origin are injured or killed by non-freezing low temperatures, and exhibit various symptoms of chilling injury such as chlorosis, necrosis, or growth retardation. In contrast, chilling tolerant species are able to grow at such cold temperatures. Conventional breeding methods have met with limited success in improving the cold tolerance of important crop plants involving inter-specific or inter-generic hybridization. Recent studies involving full genome profiling/ sequencing, mutational and transgenic plant analyses, have provided a deep insight of the complex transcriptional mechanism that operates under cold stress. The alterations in expression of genes in response to cold temperatures are followed by increases in the levels of hundreds of metabolites, some of which are known to have protective effects against the damaging effects of cold stress. Various low temperature inducible genes have been isolated from plants. Most appear to be involved in tolerance to cold stress and the expression of some of them is regulated by C-repeat binding factor/ dehydration-responsive element binding (CBF/DREB1) transcription factors. Numerous physiological and molecular changes occur during cold acclimation which reveals that the cold resistance is more complex than perceived and involves more than one pathway. The findings summarized in this review have shown potential practical applications for breeding cold tolerance in crop and horticultural plants suitable to temperate geographical locations. PMID:21886453

  4. Analysis and simulation of a cold-air pool and high wintertime ozone episode in Utah's Uintah Basin

    NASA Astrophysics Data System (ADS)

    Neemann, Erik M.

    High ozone concentrations associated with a winter cold-air pool during the Uintah Basin Winter Ozone Study are investigated. Field campaign observations combined with numerical simulations are analyzed in Utah's Uintah Basin from 1-6 February 2013 when ozone concentrations exceeded 150 ppb. Cold-air pool sensitivity to cloud microphysics and snow cover variations within the Weather Research and Forecasting model simulations are examined, along with their impact on air quality in Community Multiscale Air Quality model simulations. Ice-dominant clouds are found to enhance cold-air pool strength compared to liquid-dominant clouds through increased nocturnal cooling and decreased longwave cloud forcing. The presence of snow cover also strengthens cold-air pool structure by lowering near-surface air temperatures and increasing boundary layer stability due to reduced absorbed solar insolation by the high-albedo snow surface. Snow cover also increases ozone levels by enhancing solar radiation available for photochemical reactions. Flow features affecting Uintah Basin cold-air pools that affect pollutant mixing and air quality within the basin are studied, including: penetration of clean air into the basin from across the surrounding mountains, elevated easterlies within the inversion layer, and diurnal upslope and drainage flows.

  5. Integration of regenerative shock absorber into vehicle electric system

    NASA Astrophysics Data System (ADS)

    Zhang, Chongxiao; Li, Peng; Xing, Shaoxu; Kim, Junyoung; Yu, Liangyao; Zuo, Lei

    2014-03-01

    Regenerative/Energy harvesting shock absorbers have a great potential to increase fuel efficiency and provide suspension damping simultaneously. In recent years there's intensive work on this topic, but most researches focus on electricity extraction from vibration and harvesting efficiency improvement. The integration of electricity generated from regenerative shock absorbers into vehicle electric system, which is very important to realize the fuel efficiency benefit, has not been investigated. This paper is to study and demonstrate the integration of regenerative shock absorber with vehicle alternator, battery and in-vehicle electrical load together. In the presented system, the shock absorber is excited by a shaker and it converts kinetic energy into electricity. The harvested electricity flows into a DC/DC converter which realizes two functions: controlling the shock absorber's damping and regulating the output voltage. The damping is tuned by controlling shock absorber's output current, which is also the input current of DC/DC converter. By adjusting the duty cycles of switches in the converter, its input impedance together with input current can be adjusted according to dynamic damping requirements. An automotive lead-acid battery is charged by the DC/DC converter's output. To simulate the working condition of combustion engine, an AC motor is used to drive a truck alternator, which also charges the battery. Power resistors are used as battery's electrical load to simulate in-vehicle electrical devices. Experimental results show that the proposed integration strategy can effectively utilize the harvested electricity and power consumption of the AC motor is decreased accordingly. This proves the combustion engine's load reduction and fuel efficiency improvement.

  6. Accuracy of the Independent Pixel Approximation at Absorbing Wavelengths

    NASA Technical Reports Server (NTRS)

    Marchak, Alexander; Oreopoulos, Lazaros; Davis, Anthony; Wiscombe, Warren; Cahalan, Robert

    1999-01-01

    In order to correctly interpret shortwave cloud radiation measured by satellites and ground-based radiometers, or by two aircraft flying above and below clouds, we need to better understand interactions between inhomogeneous clouds and solar radiation. The discrepancies between shortwave absorption inferred from measurements and predicted by models, between cloud optical depths estimated from satellites and ground measurements, between single scattering albedo retrieved from in situ radiation measurements and computed from measured droplet size distribution, among others, are strongly affected by cloud horizontal inhomogeneity. Net horizontal photon transport (i. e., horizontal fluxes) are a direct consequence of the inhomoqeneity in cloud structure. Horizontal fluxes and their effect on the accuracy of the pixel-by-pixel one-dimensional (1 D) radiative transfer calculations has recently undergone close scrutiny for conservative scattering. However, the properties and magnitude of horizontal fluxes in absorbing wavelengths are still poorly understood. As far as we are aware, only Ackerman and Cox and Titov discussed correlations between horizontal fluxes at absorbing wavelengths, though these were far from comprehensive. This paper partly fills this gap. We discuss here of whether the accuracy of the Independent Pixel Approximation (IPA), a 1 D radiative transfer approximation for each pixel, is a better model for multiple scattering at conservative or at absorbing wavelengths. Issues addressed here are: (1) dependence of net horizontal fluxes on single scattering albedo; (2) connection between pixel-by-pixel accuracy of the IPA and horizontal fluxes and (3) radiative smoothing and horizontal fluxes at absorbing wavelengths. In contrast to the traditional understanding of IPA, we study IPA accuracies not only for reflectance but also for transmittance and absorptance at both conservative and absorbing wavelengths. In spite of the apparent similarity between the three processes, dependence of IPA accuracies on single-scattering albedo is completely different. As a result, cloud optical properties retrieved from high resolution satellite images and ground-based measurements using IPA at absorbing channels will have different accuracies.

  7. Absorbed dose in target cell nuclei and dose conversion coefficient of radon progeny

    E-print Network

    Yu, K.N.

    Abstract To calculate the absorbed dose in the human lung due to inhaled radon progeny, ICRP focussed the absorbed dose in the human lung due to inhaled radon progeny, ICRP66 (ICRP, 1994) made use of the absorbed of alpha particles emitted in that source to give the energy absorbed in the target. ICRP66 considered

  8. CMB Cold Spot from Inflationary Feature Scattering

    E-print Network

    Yi Wang; Yin-Zhe Ma

    2015-01-01

    We propose a "feature-scattering" mechanism to explain the cosmic microwave background cold spot seen from {\\it WMAP} and {\\it Planck} maps. If there are hidden features in the potential of multi-field inflation, the inflationary trajectory can be scattered by such features. The scattering is controlled by the amount of isocurvature fluctuations, and thus can be considered as a mechanism to convert isocurvature fluctuations into curvature fluctuations. This mechanism predicts localized cold spots (instead of hot ones) on the CMB. In addition, it may also bridge a connection between the cold spot and a dip on the CMB power spectrum at $\\ell \\sim 20$.

  9. Trapping Cold Atoms by a Carbon Nanotube

    NASA Astrophysics Data System (ADS)

    Chu, T. A.; Nga, D. T.; Thao, T. T.; Ngo, V. Thanh; Viet, N. A.

    A new model of cold atoms trap using a carbon nanotube is proposed. In this model, for the existence of a stable bound state of cold atom, we send a strong electromagnetic field through the carbon nanotube. This field generates an evanescent wave around the carbon nanotube and creates an effective attractive potential. The consideration of some possible boundary conditions leads to this non-trivial bound state solution. We compare also our result to the two most recent models concerning trapping of cold atoms by using a charged carbon nanotube and an optical fiber.

  10. Cold Clouds and Water in Space

    NSDL National Science Digital Library

    Helen Matsos

    2001-01-01

    This article from Astrobiology Magazine reports on the discovery of water in cold regions of space. Using data from the European Space Agencys Infrared Space Observatory, astronomers have determined that water is abundant in these cold, or quiescent regions of space where there are no stars, and that the majority of it occurs as ice with a small amount of water vapor. It is thought that these cold regions of space might be the future birthplaces of low-mass stars like our own sun. Links to other related sites are provided and a Spanish translation is available.

  11. Compare and contrast warm and cold fronts

    NSDL National Science Digital Library

    TERC. Center for Earth and Space Science Education

    2003-01-01

    This pair of Earth science animations show students what happens at cold and warm fronts as clouds are formed by the interaction of warm air and cool air. The cool front animation depicts cumulonimbus clouds forming as a cold front moves into a region of warm air and forces the warm air to rise. In contrast, the warm front animation shows how warm air, moving over cold air, causes a progression of nimbostratus to cirrus clouds to form. Movie controls allow students to repeat, pause, or step through the animations, which can give students more time to analyze the images. Copyright 2005 Eisenhower National Clearinghouse

  12. Parallel-Plate Acoustic Absorbers For Hot Environments

    NASA Technical Reports Server (NTRS)

    Doychak, Joseph; Parrot, Tony L.

    1995-01-01

    Stacking patterns and materials chosen to suppress noise. Acoustic liners incorporating parallel-plate absorbing elements proposed for use in suppressing broadband aerodynamic noise originating in flows of hot gases in ducts. One potential application lies in suppressing noise generated in exhaust-jet mixer/ejectors in propulsion system of proposed High-Speed Civil Transport. In addition, such absorbers useful in any situation in which high temperature limits use of such conventional resonant acoustic-liner materials as perforated face sheets bonded to honey-comb-core panels.

  13. Spin -1/2 Particle in an Absorbing Environment

    NASA Astrophysics Data System (ADS)

    Amooshahi, M.

    2015-03-01

    The quantum dynamics of a localized spin -1/2 Particle interacting with an absorbing environment is investigated. The quantum Langevin-Schrödinger equation for spin -1/2 is obtained. The susceptibility function of the environment is calculated in terms of the coupling function of the spin and the environment. it is shown that the susceptibility function satisfies the Kramers-Kronig relations. Spontaneous emission and the shift frequency of the spin is obtained in terms of the imaginary part of the susceptibility function in frequency domain. Some transition probabilities between the spin states are calculated when the absorbing environment is in the thermal state.

  14. Radiographic fallopian tube recanalization: Absorbed ovarian radiation dose

    SciTech Connect

    Hedgpeth, P.L.; Thurmond, A.S.; Fry, R.; Schmidgall, J.R.; Roesch, J. (Department of Diagnostic Radiology, Oregon Health Sciences University, Portland (USA))

    1991-07-01

    Absorbed radiation dose to the ovaries during radiographic fallopian tube recanalization was estimated in 29 patients with use of thermoluminescent dosimeters placed in the vaginal fornix. With an average fluoroscopic time of 8.5 minutes {plus minus} 5.5 and an average of 14 {plus minus} 5 105-mm spot radiographs obtained, the average absorbed dose to the ovaries was 8.5 mGy {plus minus} 5.6 (0.85 rad {plus minus} 0.56). Technical guidelines for keeping patient radiation exposure to a minimum during this new interventional procedure are suggested.

  15. Photophoretic trampoline - Interaction of single airborne absorbing droplets with light

    E-print Network

    Esseling, Michael; Alpmann, Christina; Denz, Cornelia

    2012-01-01

    We present the light-induced manipulation of absorbing liquid droplets in air. Ink droplets from a printer cartridge are used to demonstrate that absorbing liquids - just like their solid counterparts - can interact with regions of high light intensity due to the photophoretic force. It is shown that droplets follow a quasi-ballistic trajectory after bouncing off a high intensity light sheet. We estimate the intensities necessary for this rebound of airborne droplets and change the droplet trajectories through a variation of the manipulating light field.

  16. Croconic acid - An absorber in the Venus clouds?

    NASA Technical Reports Server (NTRS)

    Hartley, Karen K.; Wolff, Andrew R.; Travis, Larry D.

    1989-01-01

    The absorbing species responsible for the UV cloud features and pale yellow hue of the Venus clouds is presently suggested to be the carbon monoxide-polymer croconic acid, which strongly absorbs in the blue and near-UV. Laboratory absorption-coefficient measurements of a dilute solution of croconic acid in sulfuric acid are used as the bases of cloud-scattering models; the Venus planetary albedo's observed behavior in the blue and near-UV are noted to be qualitatively reproduced. Attention is given to a plausible croconic acid-production mechanism for the Venus cloudtop region.

  17. R-SQUARE IMPEDANCES OF ERL FERRITE HOM ABSORBER.

    SciTech Connect

    HAHN, H.; BURRILL, A.; CALAGA,R.; KAYRAN, D.; ZHAO, Y.

    2005-07-10

    An R&D facility for an Energy Recovery Linac (ERL) intended as part of an electron-cooling project for RHIC is, being constructed at this laboratory. The center piece of the facility is a 5-cell 703.75 MHz super-conducting RF linac. Successful operation will depend on effective HOM damping. It is planned to achieve HOM damping exclusively with ferrite absorbers. The performance of a prototype absorber was measured by transforming it into a resonant cavity and alternatively by a conventional wire method. The results expressed as a surface or R-square impedance are presented in this paper.

  18. Croconic acid - An absorber in the Venus clouds

    SciTech Connect

    Hartley, K.K.; Wolff, A.R.; Travis, L.D.

    1989-02-01

    The absorbing species responsible for the UV cloud features and pale yellow hue of the Venus clouds is presently suggested to be the carbon monoxide-polymer croconic acid, which strongly absorbs in the blue and near-UV. Laboratory absorption-coefficient measurements of a dilute solution of croconic acid in sulfuric acid are used as the bases of cloud-scattering models; the Venus planetary albedo's observed behavior in the blue and near-UV are noted to be qualitatively reproduced. Attention is given to a plausible croconic acid-production mechanism for the Venus cloudtop region. 34 references.

  19. MSAT boom joint testing and load absorber design

    NASA Technical Reports Server (NTRS)

    Klinker, D. H.; Shuey, K.; St.clair, D. R.

    1994-01-01

    Through a series of component and system-level tests, the torque margin for the MSAT booms is being determined. The verification process has yielded a number of results and lessons that can be applied to many other types of deployable spacecraft mechanisms. The MSAT load absorber has proven to be an effective way to provide high energy dissipation using crushable honeycomb. Using two stages of crushable honeycomb and a fusible link, a complex crush load profile has been designed and implemented. The design features of the load absorber lend themselves to use in other spacecraft applications.

  20. Vibration analysis of rotor blades with pendulum absorbers

    NASA Technical Reports Server (NTRS)

    Murthy, V. R.; Hammond, C. E.

    1979-01-01

    A comprehensive vibration analysis of rotor blades with spherical pendulum absorbers is presented. Linearized equations of motion for small oscillations about the steady-state deflection of a spherical pendulum on elastic rotor blades undergoing coupled flapwise bending, chordwise bending, and torsional vibrations are obtained. A transmission matrix formulation is given to determine the natural vibrational characteristics of rotor blades with spherical or simple flapping pendulum absorbers. The natural frequencies and mode shapes of a hingeless rotor blade with a spherical pendulum are computed.

  1. An extremely broad band metamaterial absorber based on destructive interference.

    PubMed

    Sun, Jingbo; Liu, Lingyun; Dong, Guoyan; Zhou, Ji

    2011-10-24

    We propose a design of an extremely broad frequency band absorber based on destructive interference mechanism. Metamaterial of multilayered SRRs structure is used to realize a desirable refractive index dispersion spectrum, which can induce a successive anti-reflection in a wide frequency range. The corresponding high absorptance originates from the destructive interference of two reflection waves from the two surfaces of the metamaterial. A strongly absorptive bandwidth of almost 60 GHz is demonstrated in the range of 0 to 70 GHz numerically. This design provides an effective and feasible way to construct broad band absorber in stealth technology, as well as the enhanced transmittance devices. PMID:22108966

  2. The Warm Absorber of the Seyfert Galaxy NGC 5548

    NASA Astrophysics Data System (ADS)

    Andrade, M.; Krongold, Y.; Elvis, M.; Nicastro, F.; Binette, L.; Brickhouse, N.

    2008-04-01

    We present a spectral analysis of the X-ray Chandraof the Seyfert 1 Galaxy NGC 5548. The warm absorber present in this object was modeled with the code PHASE. We detected two different outflow velocity systems in this source. One of the absorbing systems has outflow velocity of -1091+/-63 km s(-1) and the other of -568+/-49 km s(-1) . Each system required two absorption components with different ionization level to fit the observed features. Each velocity system may consist of a multi-phase medium.

  3. Bistability By Self-Reflection In A Saturable Absorber

    NASA Astrophysics Data System (ADS)

    Roso-Franco, Luis

    1987-01-01

    Propagation of laser light through a saturable absorber is theoretically studied. Computed steady state solutions of the Maxwell equations describing the unidimensional propagation of a plane monochromatic wave without introducing the slowly-varying envelope approximation are presented showing how saturation effects can influence the absorption of the field. At a certain range of refractive index and extintion coefficients, computed solutions display a very susprising behaviour, and a self-reflected wave appears inside the absorber. This can be useful for a new kind of biestable device, similar to a standard bistable cavity but with the back mirror self-induced by the light.

  4. Integrity of neutron-absorbing components of LWR fuel systems

    SciTech Connect

    Bailey, W.J.; Berting, F.M.

    1991-03-01

    A study of the integrity and behavior of neutron-absorbing components of light-water (LWR) fuel systems was performed by Pacific Northwest Laboratory (PNL) and sponsored by the US Department of Energy (DOE). The components studies include control blades (cruciforms) for boiling-water reactors (BWRs) and rod cluster control assemblies for pressurized-water reactors (PWRs). The results of this study can be useful for understanding the degradation of neutron-absorbing components and for waste management planning and repository design. The report includes examples of the types of degradation, damage, or failures that have been encountered. Conclusions and recommendations are listed. 84 refs.

  5. High-Efficiency Absorber for Damping the Transverse Wake Fields

    SciTech Connect

    Novokhatski, A.; Seeman, J.; Weathersby, S.; /SLAC

    2007-02-28

    Transverse wake fields generated by intense beams may propagate long distances in the vacuum chamber and dissipate power in different shielded elements such as bellows, vacuum valves or vacuum pumps. Induced heating in these elements may be high enough to deteriorate vacuum conditions. We have developed a broadband water-cooled bellows-absorber to capture and damp these harmful transverse fields without impacting the longitudinal beam impedance. Experimental results at the PEP-II SLAC B-factory demonstrate high efficiency of this device. This absorber may be useful in other machines like synchrotron light sources or International Linear Collider.

  6. Energy deposition and radiological studies for the LBNF Hadron Absorber

    E-print Network

    Rakhno, I L; Tropin, I S; Eidelman, Y I

    2015-01-01

    Results of detailed Monte Carlo energy deposition and radiological studies performed for the LBNF hadron absorber with the MARS15 code are described. The model of the entire facility, that includes a pion-production target, focusing horns, target chase, decay channel, hadron absorber system - all with corresponding radiation shielding - was developed using the recently implemented ROOT-based geometry option in the MARS15 code. Both normal operation and accidental conditions were studied. Results of detailed thermal calculations with the ANSYS code helped to select the most viable design options.

  7. Cold Dust in Hot Regions

    NASA Astrophysics Data System (ADS)

    Sreenilayam, Gopika; Fich, Michel; Ade, Peter; Bintley, Dan; Chapin, Ed; Chrysostomou, Antonio; Dunlop, James S.; Gibb, Andy; Greaves, Jane S.; Halpern, Mark; Holland, Wayne S.; Ivison, Rob; Jenness, Tim; Robson, Ian; Scott, Douglas

    2014-03-01

    We mapped five massive star-forming regions with the SCUBA-2 camera on the James Clerk Maxwell Telescope. Temperature and column density maps are obtained from the SCUBA-2 450 and 850 ?m images. Most of the dense clumps we find have central temperatures below 20 K, with some as cold as 8 K, suggesting that they have no internal heating due to the presence of embedded protostars. This is surprising, because at the high densities inferred from these images and at these low temperatures such clumps should be unstable, collapsing to form stars and generating internal heating. The column densities at the clump centers exceed 1023 cm-2, and the derived peak visual extinction values are from 25 to 500 mag for ? = 1.5-2.5, indicating highly opaque centers. The observed cloud gas masses range from ~10 to 103 M ?. The outer regions of the clumps follow an r -2.36 ± 0.35 density distribution, and this power-law structure is observed outside of typically 104 AU. All these findings suggest that these clumps are high-mass starless clumps and most likely contain high-mass starless cores.

  8. Cold Flow Verification Test Facility

    SciTech Connect

    Shamsi, A.; Shadle, L.J.

    1996-12-31

    The cold flow verification test facility consists of a 15-foot high, 3-foot diameter, domed vessel made of clear acrylic in two flanged sections. The unit can operate up to pressures of 14 psig. The internals include a 10-foot high jetting fluidized bed, a cylindrical baffle that hangs from the dome, and a rotating grate for control of continuous solids removal. The fluid bed is continuously fed solids (20 to 150 lb/hr) through a central nozzle made up of concentric pipes. It can either be configured as a half or full cylinder of various dimensions. The fluid bed has flow loops for separate air flow control for conveying solids (inner jet, 500 to 100000 scfh) , make-up into the jet (outer jet, 500 to 8000 scfh), spargers in the solids removal annulus (100 to 2000 scfh), and 6 air jets (20 to 200 scfh) on the sloping conical grid. Additional air (500 to 10000 scfh) can be added to the top of the dome and under the rotating grate. The outer vessel, the hanging cylindrical baffles or skirt, and the rotating grate can be used to study issues concerning moving bed reactors. There is ample allowance for access and instrumentation in the outer shell. Furthermore, this facility is available for future Cooperative Research and Development Program Manager Agreements (CRADA) to study issues and problems associated with fluid- and fixed-bed reactors. The design allows testing of different dimensions and geometries.

  9. Cold dust in hot regions

    SciTech Connect

    Sreenilayam, Gopika; Fich, Michel [Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario, N2L 3G1 (Canada); Ade, Peter [Cardiff School of Physics and Astronomy, Cardiff University, Queen's Building, The Parade, Cardiff CF24 3AA (United Kingdom); Bintley, Dan; Chapin, Ed; Chrysostomou, Antonio; Jenness, Tim [Joint Astronomy Centre, 660 N. A'ohoku Place, University Park, Hilo, HI 96720 (United States); Dunlop, James S.; Holland, Wayne S.; Ivison, Rob [Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ (United Kingdom); Gibb, Andy; Halpern, Mark; Scott, Douglas [Department of Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver BC V6T 1Z1 (Canada); Greaves, Jane S. [School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews, Fife KY16 9SS (United Kingdom); Robson, Ian [UK Astronomy Technology Centre, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ (United Kingdom)

    2014-03-01

    We mapped five massive star-forming regions with the SCUBA-2 camera on the James Clerk Maxwell Telescope. Temperature and column density maps are obtained from the SCUBA-2 450 and 850 ?m images. Most of the dense clumps we find have central temperatures below 20 K, with some as cold as 8 K, suggesting that they have no internal heating due to the presence of embedded protostars. This is surprising, because at the high densities inferred from these images and at these low temperatures such clumps should be unstable, collapsing to form stars and generating internal heating. The column densities at the clump centers exceed 10{sup 23} cm{sup –2}, and the derived peak visual extinction values are from 25 to 500 mag for ? = 1.5-2.5, indicating highly opaque centers. The observed cloud gas masses range from ?10 to 10{sup 3} M {sub ?}. The outer regions of the clumps follow an r {sup –2.36±0.35} density distribution, and this power-law structure is observed outside of typically 10{sup 4} AU. All these findings suggest that these clumps are high-mass starless clumps and most likely contain high-mass starless cores.

  10. Exchanging Ohmic losses in metamaterial absorbers with useful optical absorption for photovoltaics.

    PubMed

    Vora, Ankit; Gwamuri, Jephias; Pala, Nezih; Kulkarni, Anand; Pearce, Joshua M; Güney, Durdu Ö

    2014-01-01

    Using metamaterial absorbers, we have shown that metallic layers in the absorbers do not necessarily constitute undesired resistive heating problem for photovoltaics. Tailoring the geometric skin depth of metals and employing the natural bulk absorbance characteristics of the semiconductors in those absorbers can enable the exchange of undesired resistive losses with the useful optical absorbance in the active semiconductors. Thus, Ohmic loss dominated metamaterial absorbers can be converted into photovoltaic near-perfect absorbers with the advantage of harvesting the full potential of light management offered by the metamaterial absorbers. Based on experimental permittivity data for indium gallium nitride, we have shown that between 75%-95% absorbance can be achieved in the semiconductor layers of the converted metamaterial absorbers. Besides other metamaterial and plasmonic devices, our results may also apply to photodectors and other metal or semiconductor based optical devices where resistive losses and power consumption are important pertaining to the device performance. PMID:24811322

  11. Exchanging Ohmic Losses in Metamaterial Absorbers with Useful Optical Absorption for Photovoltaics

    PubMed Central

    Vora, Ankit; Gwamuri, Jephias; Pala, Nezih; Kulkarni, Anand; Pearce, Joshua M.; Güney, Durdu Ö.

    2014-01-01

    Using metamaterial absorbers, we have shown that metallic layers in the absorbers do not necessarily constitute undesired resistive heating problem for photovoltaics. Tailoring the geometric skin depth of metals and employing the natural bulk absorbance characteristics of the semiconductors in those absorbers can enable the exchange of undesired resistive losses with the useful optical absorbance in the active semiconductors. Thus, Ohmic loss dominated metamaterial absorbers can be converted into photovoltaic near-perfect absorbers with the advantage of harvesting the full potential of light management offered by the metamaterial absorbers. Based on experimental permittivity data for indium gallium nitride, we have shown that between 75%–95% absorbance can be achieved in the semiconductor layers of the converted metamaterial absorbers. Besides other metamaterial and plasmonic devices, our results may also apply to photodectors and other metal or semiconductor based optical devices where resistive losses and power consumption are important pertaining to the device performance. PMID:24811322

  12. Ingestion of a Cold Temperature/Menthol Beverage Increases Outdoor Exercise Performance in a Hot, Humid Environment

    PubMed Central

    2015-01-01

    Purpose A recent laboratory study demonstrated that the ingestion of a cold/menthol beverage improved exercise performance in a hot and humid environment during 20 km of all-out cycling. Therefore, the aim of this study was to determine whether the ingestion of cold water/ice-slurry with menthol would improve performance in hot and humid outdoor conditions. Methods Ten trained males completed three trials of five blocks consisting of 4-km cycling and 1.5-km running. During warm-up, every block and recovery, the athletes drank 190 ml of aromatized (i.e., with 0.05 mL of menthol) beverage at three temperatures: Neutral (ambient temperature) (28.7°C±0. 5°C), Cold (3.1°C±0.6°C) or Ice-slurry (0.17°C±0.07°C). Trial time, core temperature (Tco), heart rate (HR), rate of perceived exertion (RPE), thermal sensation (TS) and thermal comfort (TC) were assessed. Results Ice-slurry/menthol increased performance by 6.2% and 3.3% compared with neutral water/menthol and cold water/menthol, respectively. No between-trial differences were noted for Tco, HR, RPE, TC and TS was lower with ice-slurry/menthol and cold water/menthol compared with neutral water/menthol. Conclusion A low drink temperature combined with menthol lessens the performance decline in hot/humid outdoor conditions (i.e., compared with cold water alone). Performances were better with no difference in psycho-physiological stress (Tco, HR and RPE) between trials. The changes in perceptual parameters caused by absorbing a cold/menthol beverage reflect the psychological impact. The mechanism leading to these results seems to involve brain integration of signals from physiological and psychological sources. PMID:25856401

  13. First-order optimal linear and nonlinear detuning of centrifugal pendulum vibration absorbers

    NASA Astrophysics Data System (ADS)

    Mayet, J.; Ulbrich, H.

    2015-01-01

    Centrifugal pendulum vibration absorbers are used to attenuate steady-state torsional vibrations in rotating and reciprocating machines. In most practical implementations, a set of multiple absorbers is symmetrically arranged on a rotor. Typically, each absorber mass is bifilar suspended, which allows the absorber mass to be moved along a prescribed path. Previous studies have considered how to determine absorber paths in order to obtain absorbers with amplitude-independent frequency known as tautochronic absorbers. It is known that a tautochronic absorber is highly desirable if only one absorber is installed on the rotor. However, in most applications multiple interacting absorbers are installed and as a result symmetry-induced nonlinear instabilities or localization caused by relative imperfections among the absorbers may occur. An effective strategy to avoid such situations is to perturb the tautochronic tuning which has been confirmed in practice and by previous theoretical investigations. This paper presents an approach for detuning a recently developed general tautochronic absorber design. The general design makes it possible to consider a wide class of tautochronic absorbers, e.g. absorbers without bifilar suspensions. The intent of this paper is to extend the existing tautochronic design guideline to non-tautochronic designs. As a result, different absorber designs can be addressed by one uniform theoretical approach, and existing absorber designs are included as special cases. Former studies on detuning of bifilar tautochronic absorbers use a one-parameter family of curves on which the absorber mass rides. Here, however, the detuning is not restricted to a one-parameter family of curves, which makes it possible to either optimize system performance or to avoid asynchronous absorber responses. In the case of synchronously responding equal absorbers, a necessary condition for optimal performance is derived analytically. Further, it is shown that asynchronous responses can be avoided by applying positive detuning.

  14. Cold-induced changes in amphibian oocytes

    SciTech Connect

    Angelier, N.; Moreau, N.A.; N'Da, E.A.; Lautredou, N.F. (Centre de Biologie Cellulaire, Ivry-sur-Seine (France))

    1989-08-01

    Female Pleurodeles waltl newts (Amphibia, urodele), usually raised at 20 degrees C, were submitted to low temperatures; oocytes responded to this cold stress by drastic changes both in lampbrush chromosome structure and in protein pattern. Preexisting lateral loops of lampbrush chromosomes were reduced in size and number, while cold-induced loops which were tremendously developed, occurred on defined bivalents of the oocyte at constant, reproducible sites. A comparison of protein patterns in control and stressed oocytes showed two main differences: in stressed oocytes, overall protein synthesis was reduced, except for a set of polypeptides, the cold-stress proteins; second, there was a striking inversion of the relative amount of beta- and gamma-actin found in the oocyte nucleus before and after cold stress. Whereas beta-actin was the predominant form in control oocytes, gamma-actin became the major form in stressed oocytes.

  15. Cold vacuum drying facility design requirements

    SciTech Connect

    Irwin, J.J.

    1997-09-24

    This release of the Design Requirements Document is a complete restructuring and rewrite to the document previously prepared and released for project W-441 to record the design basis for the design of the Cold Vacuum Drying Facility.

  16. The Cold War: A Yearbook Perspective.

    ERIC Educational Resources Information Center

    Graebner, William

    1986-01-01

    Shows how the photographs, valedictorian addresses, nicknames, cartoons and other material contained in high school yearbook can yield information regarding the world views of Americans at the start of the Cold War. (JDH)

  17. Compatible Transfusion Therapy for Paroxysmal Cold Hemoglobinuria

    ERIC Educational Resources Information Center

    Rausen, Aaron R.; And Others

    1975-01-01

    Presented are case histories of two children, ages 2 and 4 years, with paroxysmal cold hemoglobinuria (PCH, a syndrome characterized by acute intravascular hemoglobin dissolution and hemoglobin in the urine). (Author/CL)

  18. Cold denaturation of ?-synuclein amyloid fibrils.

    PubMed

    Ikenoue, Tatsuya; Lee, Young-Ho; Kardos, József; Saiki, Miyu; Yagi, Hisashi; Kawata, Yasushi; Goto, Yuji

    2014-07-21

    Although amyloid fibrils are associated with numerous pathologies, their conformational stability remains largely unclear. Herein, we probe the thermal stability of various amyloid fibrils. ?-Synuclein fibrils cold-denatured to monomers at 0-20?°C and heat-denatured at 60-110?°C. Meanwhile, the fibrils of ?2-microglobulin, Alzheimer's A?1-40/A?1-42 peptides, and insulin exhibited only heat denaturation, although they showed a decrease in stability at low temperature. A comparison of structural parameters with positive enthalpy and heat capacity changes which showed opposite signs to protein folding suggested that the burial of charged residues in fibril cores contributed to the cold denaturation of ?-synuclein fibrils. We propose that although cold-denaturation is common to both native proteins and misfolded fibrillar states, the main-chain dominated amyloid structures may explain amyloid-specific cold denaturation arising from the unfavorable burial of charged side-chains in fibril cores. PMID:24920162

  19. Wire and Cable Cold Bending Test

    NASA Technical Reports Server (NTRS)

    Colozza, Anthony

    2010-01-01

    One of the factors in assessing the applicability of wire or cable on the lunar surface is its flexibility under extreme cold conditions. Existing wire specifications did not address their mechanical behavior under cold, cryogenic temperature conditions. Therefore tests were performed to provide this information. To assess this characteristic 35 different insulated wire and cable pieces were cold soaked in liquid nitrogen. The segments were then subjected to bending and the force was recorded. Any failure of the insulation or jacketing was also documented for each sample tested. The bending force tests were performed at room temperature to provide a comparison to the change in force needed to bend the samples due to the low temperature conditions. The results from the bending tests were plotted and showed how various types of insulated wire and cable responded to bending under cold conditions. These results were then used to estimate the torque needed to unroll the wire under these low temperature conditions.

  20. Nonlinear wave propagation through cold plasma

    E-print Network

    Bindu, S G

    2015-01-01

    Electromagnetic wave propagation through cold collision free plasma is studied using the nonlinear perturbation method. It is found that the equations can be reduced to the modified Kortweg-de Vries equation.