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1

Clumpy cold dark matter  

NASA Technical Reports Server (NTRS)

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.

Silk, Joseph; Stebbins, Albert

1993-01-01

2

CLUMPY STREAMS FROM CLUMPY HALOS: DETECTING MISSING SATELLITES WITH COLD STELLAR STRUCTURES  

SciTech Connect

Dynamically cold stellar streams are ideal probes of the gravitational field of the Milky Way. This paper re-examines the question of how such streams might be used to test for the presence of {sup m}issing satellites{sup -}the many thousands of dark-matter subhalos with masses 10{sup 5}-10{sup 7} M{sub sun} which are seen to orbit within Galactic-scale dark-matter halos in simulations of structure formation in {Lambda}CDM cosmologies. Analytical estimates of the frequency and energy scales of stream encounters indicate that these missing satellites should have a negligible effect on hot debris structures, such as the tails from the Sagittarius dwarf galaxy. However, long cold streams, such as the structure known as GD1 or those from the globular cluster Palomar 5 (Pal 5), are expected to suffer many tens of direct impacts from missing satellites during their lifetimes. Numerical experiments confirm that these impacts create gaps in the debris' orbital energy distribution, which will evolve into degree- and sub-degree-scale fluctuations in surface density over the age of the debris. Maps of Pal 5's own stream contain surface density fluctuations on these scales. The presence and frequency of these inhomogeneities suggests the existence of a population of missing satellites in numbers predicted in the standard {Lambda}CDM cosmologies.

Yoon, Joo Heon; Johnston, Kathryn V. [Department of Astronomy, Columbia University, New York, NY 10027 (United States); Hogg, David W., E-mail: jhyoon@astro.columbia.edu [Center for Cosmology and Particle Physics, Department of Physics, New York University, New York, NY 10003 (United States)

2011-04-10

3

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

NASA Astrophysics Data System (ADS)

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?

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

4

Resolved shocks in clumpy media  

E-print Network

We study the structure of shocks in clumpy media, using a multifluid formalism. As expected, shocks broaden as they weaken: for sufficiently weak shocks, no viscous subshock appears in the structure. This has significant implications for the survival of dense clouds in regions overrun by shocks in a wide range of astrophysical circumstances, from planetary nebulae to the nuclei of starburst galaxies.

R. J. R. Williams; J. E. Dyson

2001-11-20

5

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

NASA Astrophysics Data System (ADS)

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.

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

2014-01-01

6

The properties of the clumpy torus and BLR in the polar-scattered Seyfert 1 galaxy ESO 323-G77 through X-ray absorption variability  

NASA Astrophysics Data System (ADS)

We report results from multi-epoch (2006-2013) X-ray observations of the polar-scattered Seyfert 1 galaxy ESO 323-G77. The source exhibits remarkable spectral variability from months to years timescales. The observed spectral variability is entirely due to variations of the column density of a neutral absorber towards the intrinsic nuclear continuum. The column density is generally Compton-thin ranging from a few times 1022 cm-2 to a few times 1023 cm-2. However, one observation reveals a Compton-thick state with column density of the order of 1.5 × 1024 cm-2. The observed variability offers a rare opportunity to study the properties of the X-ray absorber(s) in an active galaxy. We identify variable X-ray absorption from two different components, namely (i) a clumpy torus whose individual clumps have a density of ?1.7 × 108 cm-3 and an average column density of ˜4 × 1022 cm-2, and (ii) the broad-line region (BLR), comprising individual clouds with density of 0.1-8 × 109 cm-3 and column density of 1023-1024 cm-2. The derived properties of the clumpy torus can also be used to estimate the torus half-opening angle, which is of the order of 47°. We also confirm the previously reported detection of two highly ionized warm absorbers with outflow velocities of 1000-4000 km s-1. The observed outflow velocities are consistent with the Keplerian/escape velocity at the BLR. Hence, the warm absorbers may be tentatively identified with the warm/hot intercloud medium which ensures that the BLR clouds are in pressure equilibrium with their surroundings. The BLR line-emitting clouds may well be the cold, dense clumps of this outflow, whose warm/hot phase is likely more homogeneous, as suggested by the lack of strong variability of the warm absorber(s) properties during our monitoring.

Miniutti, G.; Sanfrutos, M.; Beuchert, T.; Agís-González, B.; Longinotti, A. L.; Piconcelli, E.; Krongold, Y.; Guainazzi, M.; Bianchi, S.; Matt, G.; Jiménez-Bailón, E.

2014-01-01

7

Distribution of Damped Lyman-alpha Absorbers in a Lambda Cold Dark Matter Universe  

E-print Network

We present the results of a numerical study of a galactic wind model and its implications on the properties of damped Lyman-alpha absorbers (DLAs) using cosmological hydrodynamic simulations. We vary both the wind strength and the internal parameters of the the wind model in a series of cosmological SPH simulations that include radiative cooling and heating by a UV background, star formation, and feedback from supernovae and galactic winds. To test our simulations, we examine the DLA `rate-of-incidence' as a function of halo mass, galaxy apparent magnitude, and impact parameter. We find that the statistical distribution of DLAs does not depend on the exact values of internal numerical parameters that control the decoupling of hydrodynamic forces when the gas is ejected from starforming regions. The DLA rate-of-incidence in our simulations at z=3 is dominated by the faint galaxies with apparent magnitude R_AB < 25.5. However, interestingly in a `strong wind' run, the differential distribution of DLA sight-lines is peaked at Mhalo = 10^{12} Msun/h (R_AB~27), and the mean DLA halo mass is Mmean=10^{12.4} Msun/h (R_AB ~ 26). These mass-scales are much larger than those if we ignore winds, because galactic wind feedback suppresses the DLA cross section in low-mass halos and increases the relative contribution to the DLA incidence from more massive halos. The DLAs in our simulations are more compact than the present-day disk galaxies, and the impact parameter distribution is very narrow unless we limit the search for the host galaxy to only bright LBGs. The comoving number density of DLAs is higher than that of LBGs down to R_AB=30 mag if the physical radius of each DLA is smaller than 5 kpc/h_70. We discuss conflicts between current simulations and observations, and potential problems with simulations based on the CDM model.

Kentaro Nagamine; Arthur M. Wolfe; Lars Hernquist; Volker Springel

2007-01-17

8

Clumpy galaxies at z ~ 0.6: kinematics, stability and comparison with analogues at other redshifts  

NASA Astrophysics Data System (ADS)

Distant clumpy galaxies are thought to be Jeans-unstable discs and an important channel for the formation of local galaxies, as suggested by recent spatially resolved kinematic observations of z ~ 2 galaxies. I study the kinematics of clumpy galaxies at z ~ 0.6 and compare their properties with those of counterparts at higher and lower redshifts. I selected a sample of 11 clumpy galaxies at z ~ 0.6 from the representative sample of emission-line, intermediate-mass galaxies IMAGES. Selection was based on rest-frame UV morphology from Hubble Space Telescope/Advanced Camera for Surveys images, mimicking the selection criteria commonly used at higher redshifts. Their spatially resolved kinematics were derived in the frame of the IMAGES survey, using the Very Large Telescope/FLAMES-GIRAFFE multi-integral field spectrograph. For those showing large-scale rotation, I derived the Toomre Q parameter, which characterizes the stability of their gaseous and stellar phases. I find that the fraction of UV-selected clumpy galaxies at z ~ 0.6 is 20 +/- 12 per cent. Roughly half of them (45 +/- 30 per cent) have complex kinematics inconsistent with Jeans-unstable discs, while those in the remaining half (55 +/- 30 per cent) show large-scale rotations. The latter reveal a stable gaseous phase, but the contribution of their stellar phase makes them globally unstable to clump formation. Clumpy galaxies appear to be less unstable at z ~ 0.6 than at z ~ 2, which could explain why the UV clumps tend to vanish in rest-frame optical images of z ~ 0.6 clumpy galaxies, conversely to z ~ 2 clumpy galaxies, in which the stellar phase can substantially fragment. This suggests that the former correspond to patchy star formation regions superimposed on a smoother mass distribution. A possible and widespread scenario for driving clump formation relies on instabilities by cold streams penetrating the dark matter haloes where clumpy galaxies inhabit. While such a gas accretion process is predicted to be significant in massive, z ~ 2 haloes, it is also predicted to be strongly suppressed in similar, z ~ 0.6 haloes, which could explain why lowest z clumpy galaxies appear to be driven by a different mechanism. Instead, I found that interactions are probably the dominant driver leading to the formation of clumpy galaxies at z < 1. I argue that the nature of z > 1 clumpy galaxies remains more uncertain. While cold flows could be an important driver at z ~ 2, I also argue that the observed and cumulative merger fraction between z = 2 and z = 3 is large enough so that every z ~ 2 galaxy might be the result of a merger that occurred within their past 1Gyr. I conclude that it is premature to rule out mergers as a universal driver for galaxy evolution from z ~ 2 down to z = 0.

Puech, M.

2010-07-01

9

Thermal Instability and the Formation of Clumpy Gas Clouds  

E-print Network

The radiative cooling of optically thin gaseous regions and the formation of a two-phase medium and of cold gas clouds with a clumpy substructure is investigated. In optically thin clouds, the growth rate of small isobaric density perturbations is independent of their length scale. However, the growth of a perturbation is limited by its transition from isobaric to isochoric cooling. The temperature at which this transition occurs decreases with the length scale of the perturbation. Consequently small scale perturbations have the potential to reach higher amplitudes than large scale perturbations. When the amplitude becomes nonlinear, advection overtakes the pressure gradient in promoting the compression resulting in an accelerated growth of the disturbance. The critical temperature for transition depends on the initial amplitude. The fluctuations which can first reach nonlinearity before their isobaric to isochoric transition will determine the characteristic size and mass of the cold dense clumps which would emerge from the cooling of an initially nearly homogeneous region of gas. Thermal conduction is in general very efficient in erasing isobaric, small-scale fluctuations, suppressing a cooling instability. A weak, tangled magnetic field can however reduce the conductive heat flux enough for low-amplitude fluctuations to grow isobarically and become non-linear if their length scales are of order 0.01 pc. Finally, we demonstrate how a 2-phase medium, with cold clumps being pressure confined in a diffuse hot residual background component, would be sustained if there is adequate heating to compensate the energy loss.

A. Burkert; D. N. C. Lin

2000-02-04

10

The Search for Diversities in Clumpy Galaxies  

NASA Astrophysics Data System (ADS)

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.

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

2014-01-01

11

CLUMPY ACCRETION ONTO BLACK HOLES. I. CLUMPY-ADVECTION-DOMINATED ACCRETION FLOW STRUCTURE AND RADIATION  

SciTech Connect

We investigate the dynamics of clumps embedded in and confined by the advection-dominated accretion flows (ADAFs), in which collisions among the clumps are neglected. We start from the collisionless Boltzmann equation and assume that interaction between the clumps and the ADAF is responsible for transporting the angular momentum of clumps outward. The inner edge of the clumpy-ADAF is set to be the tidal radius of the clumps. We consider strong- and weak-coupling cases, in which the averaged properties of clumps follow the ADAF dynamics and are mainly determined by the black hole potential, respectively. We propose the analytical solution of the dynamics of clumps for the two cases. The velocity dispersion of clumps is one magnitude higher than the ADAF for the strong-coupling case. For the weak-coupling case, we find that the mean radial velocity of clumps is linearly proportional to the coefficient of the drag force. We show that the tidally disrupted clumps would lead to an accumulation of the debris to form a debris disk in the Shakura-Sunyaev regime. The entire hot ADAF will be efficiently cooled down by photons from the debris disk, giving rise to a collapse of the ADAF, and quench the clumpy accretion. Subsequently, evaporation of the collapsed ADAF drives resuscitate of a new clumpy-ADAF, resulting in an oscillation of the global clumpy-ADAF. Applications of the present model are briefly discussed to X-ray binaries, low ionization nuclear emission regions, and BL Lac objects.

Wang Jianmin; Cheng Cheng; Li Yanrong [Key Laboratory for Particle Astrophysics, Institute of High Energy Physics, Chinese Academy of Sciences, 19B Yuquan Road, Beijing 100049 (China)

2012-04-01

12

Parameters of type IIP SN 2012A and clumpiness effects  

NASA Astrophysics Data System (ADS)

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.

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

2015-03-01

13

Clumpy shocks and the clump mass function  

E-print Network

In this paper, we examine whether clumpy, colliding, flows could be responsible for the clump mass functions that have been observed in several regions of embedded star formation, which have been shown to be described by a Salpeter type slope. The flows presented here, which comprise a population of initially identical clumps and the calculations are performed with and without the inclusion of self-gravity. When the shock region is at its densest, we find that the clump mass spectrum is always well modelled by a Salpeter type slope. This is true regardless of whether the self-gravity is included in the simulations or not. In the non-self-gravitating simulations, this slope is retained at lower Mach numbers (Mach 5 and 10) as the simulations progress past the densest phase. In the simulations which include self-gravity, we find that low Mach number runs yield a flatter mass function after the densest phase. This is simply a result of increased coagulation due to gravitational collapse of the flows. In the high Mach number runs (Mach 20) the Salpeter slope is always lost. The self gravitating calculations also show that the sub-group of gravitationally bound clumps in which star formation occurs, always contain the most massive clumps in the population. The mass function of these bound star forming clumps is not at all similar to the Salpeter type mass function observed for stars in the field. We conclude that the clump mass function may not only have nothing to do with gravity, but also nothing to do with the star formation process and the resulting mass distribution of stars. This raises doubt over the claims that the clump mass function is the origin of the stellar IMF, for regions such as rho Oph, Serpens and the Orion B cloud.

Paul C. Clark; Ian A. Bonnell

2006-03-21

14

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

SciTech Connect

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.

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

15

Clumpy Langmuir waves in type III radio sources  

Microsoft Academic Search

A model is developed for the clumpy Langmuir waves observed in type III source regions. In this model the waves are generated by instability of a beam which propagates outward from the Sun in a state close to marginal stability. Ambient density perturbations cause fluctuations about the marginally stable state, leading to nonuniformities in both beam and waves and, hence,

P. A. Robinson

1992-01-01

16

Competition Drives Clumpy Species Coexistence in Estuarine Phytoplankton  

PubMed Central

Understanding the mechanisms that maintain biodiversity is a fundamental problem in ecology. Competition is thought to reduce diversity, but hundreds of microbial aquatic primary producers species coexist and compete for a few essential resources (e.g., nutrients and light). Here, we show that resource competition is a plausible mechanism for explaining clumpy distribution on individual species volume (a proxy for the niche) of estuarine phytoplankton communities ranging from North America to South America and Europe, supporting the Emergent Neutrality hypothesis. Furthermore, such a clumpy distribution was also observed throughout the Holocene in diatoms from a sediment core. A Lotka-Volterra competition model predicted position in the niche axis and functional affiliation of dominant species within and among clumps. Results support the coexistence of functionally equivalent species in ecosystems and indicate that resource competition may be a key process to shape the size structure of estuarine phytoplankton, which in turn drives ecosystem functioning. PMID:23301158

Segura, A. M.; Kruk, C.; Calliari, D.; García-Rodriguez, F.; Conde, D.; Widdicombe, C. E.; Fort, H.

2013-01-01

17

Patterns of Super Star Cluster Formation in `Clumpy' Starburst Galaxies  

E-print Network

We present preliminary results from a Hubble Space Telescope (HST) WFPC2 investigation of spatial and temporal distributions of star clusters in the clumpy irregular galaxy NGC 7673 and the starburst spirals NGC 3310 and Haro 1. We compare the spectral energy distributions of star clusters in the large clumps in NGC 7673 to model calculations of stellar clusters of various ages. We also propose that the presence of super star clusters in clumps seems to be a feature of intense starbursts.

J. S. Gallagher; N. L. Homeier; C. J. Conselice; WFPC-2IDT

2000-02-07

18

Unbiased constraints on the clumpiness of universe from standard candles  

E-print Network

We perform unbiased tests for the clumpiness of 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 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 $\\Omega_m$ as well as clumpiness parameter $\\eta$ which quantifies the fraction of homogeneously distributed matter within a given light cone. At 1$\\sigma$ confidence level, the constraints are $\\Omega_m=0.34\\pm0.02$ and $\\eta=1.00^{+0.00}_{-0.02}$ from the ...

Li, Zhengxiang; Zhu, Zong-Hong

2015-01-01

19

Polarization of Dust Emission in Clumpy Molecular Clouds and Cores  

E-print Network

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.

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

2006-11-10

20

AN OCCULTATION EVENT IN CENTAURUS A AND THE CLUMPY TORUS MODEL  

SciTech Connect

We have analyzed 16 months of sustained monitoring observations of Centaurus A from the Rossi X-Ray Timing Explorer to search for changes in the absorbing column in the line of sight to the central nucleus. We present time-resolved spectroscopy which indicates that a discrete clump of material transited the line of sight to the central illuminating source over the course of {approx}170 days between 2010 August and 2011 February with a maximum increase in the column density of about 8.4 Multiplication-Sign 10{sup 22} cm{sup -2}. This is the best quality data of such an event that has ever been analyzed with the shape of the ingress and egress clearly seen. Modeling the clump of material as roughly spherical with a linearly decreasing density profile and assuming a distance from the central nucleus commensurate with the dusty torus, we found that the clump would have a diameter of (1.4-2.4) Multiplication-Sign 10{sup 15} cm with a central number density of n{sub H} = (1.8-3.0) Multiplication-Sign 10{sup 7} cm{sup -3}. This is consistent with previous results for a similar (though possibly much longer) occultation event inferred in this source in 2003-2004 and supports models of the molecular torus as a clumpy medium.

Rivers, Elizabeth; Markowitz, Alex; Rothschild, Richard, E-mail: erivers@ucsd.edu [Center for Astrophysics and Space Sciences, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0424 (United States)

2011-12-15

21

A Chandra view of the clumpy reflector at the heart of the Circinus galaxy  

NASA Astrophysics Data System (ADS)

We present a spectral and imaging analysis of the X-ray reflecting structure at the heart of the Circinus galaxy, investigating the innermost regions surrounding the central black hole. By studying an archival 200 ks Chandra Advanced CCD Imaging Spectrometer-S observation, we are able to image the extended clumpy structure responsible for both cold reflection of the primary radiation and neutral iron K? line emission. We measure an excess of the equivalent width of the iron K? line which follows an axisymmetric geometry around the nucleus on a hundred pc scale. Spectra extracted from different regions confirm a scenario in which the dominant mechanism is the reflection of the nuclear radiation from Compton-thick gas. Significant differences in the equivalent width of the iron K? emission line (up to a factor of 2) are found. It is argued that these differences are due to different scattering angles with respect to the line of sight rather than to different iron abundances.

Marinucci, A.; Miniutti, G.; Bianchi, S.; Matt, G.; Risaliti, G.

2013-12-01

22

Transition from Clumpy to Smooth Angular Diameter Distances  

E-print Network

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.

Eric V. Linder

1997-10-29

23

Bayesclumpy: Bayesian Inference with Clumpy Dusty Torus Models  

NASA Astrophysics Data System (ADS)

Our aim is to present a fast and general Bayesian inference framework based on the synergy between machine learning techniques and standard sampling methods and apply it to infer the physical properties of clumpy dusty torus using infrared photometric high spatial resolution observations of active galactic nuclei. We make use of the Metropolis-Hastings Markov Chain Monte Carlo algorithm for sampling the posterior distribution function. Such distribution results from combining all a priori knowledge about the parameters of the model and the information introduced by the observations. The main difficulty resides in the fact that the model used to explain the observations is computationally demanding and the sampling is very time consuming. For this reason, we apply a set of artificial neural networks that are used to approximate and interpolate a database of models. As a consequence, models not present in the original database can be computed ensuring continuity. We focus on the application of this solution scheme to the recently developed public database of clumpy dusty torus models. The machine learning scheme used in this paper allows us to generate any model from the database using only a factor of 10-4 of the original size of the database and a factor of 10-3 in computing time. The posterior distribution obtained for each model parameter allows us to investigate how the observations constrain the parameters and which ones remain partially or completely undetermined, providing statistically relevant confidence intervals. As an example, the application to the nuclear region of Centaurus A shows that the optical depth of the clouds, the total number of clouds, and the radial extent of the cloud distribution zone are well constrained using only six filters. The code is freely available from the authors.

Asensio Ramos, A.; Ramos Almeida, C.

2009-05-01

24

Absorb & Repel  

NSDL National Science Digital Library

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.

Kohl Children's Museum

2012-01-01

25

3-D Models of Embedded High-Mass Stars: Effects of a Clumpy Circumstellar Medium  

E-print Network

We use 3-D radiative transfer models to show the effects of clumpy circumstellar material on the observed infrared colors of high mass stars embedded in molecular clouds. We highlight differences between 3-D clumpy and 1-D smooth models which can affect the interpretation of data. We discuss several important properties of the emergent spectral energy distribution (SED): More near-infrared light (scattered and direct from the central source) can escape than in smooth 1-D models. The near- and mid-infrared SED of the same object can vary significantly with viewing angle, depending on the clump geometry along the sightline. Even the wavelength-integrated flux can vary with angle by more than a factor of two. Objects with the same average circumstellar dust distribution can have very different near-and mid-IR SEDs depending on the clump geometry and the proximity of the most massive clump to the central source. Although clumpiness can cause similar objects to have very different SEDs, there are some observable trends. Near- and mid-infrared colors are sensitive to the weighted average distance of clumps from the central source and to the magnitude of clumpy density variations (smooth-to-clumpy ratio). Far-infrared emission remains a robust measure of the total dust mass. We present simulated SEDs, colors, and images for 2MASS and Spitzer filters. We compare to observations of some UCHII regions and find that 3-D clumpy models fit better than smooth models. In particular, clumpy models with fractal dimensions in the range 2.3-2.8, smooth to clumpy ratios of <50%, and density distributions with shallow average radial density profiles fit the SEDs best.

R. Indebetouw; B. A. Whitney; K. E. Johnson; K. wood

2005-09-04

26

MIXING OF CLUMPY SUPERNOVA EJECTA INTO MOLECULAR CLOUDS  

SciTech Connect

Several lines of evidence, from isotopic analyses of meteorites to studies of the Sun's elemental and isotopic composition, indicate that the solar system was contaminated early in its evolution by ejecta from a nearby supernova. Previous models have invoked supernova material being injected into an extant protoplanetary disk, or isotropically expanding ejecta sweeping over a distant (>10 pc) cloud core, simultaneously enriching it and triggering its collapse. Here, we consider a new astrophysical setting: the injection of clumpy supernova ejecta, as observed in the Cassiopeia A supernova remnant, into the molecular gas at the periphery of an H II region created by the supernova's progenitor star. To track these interactions, we have conducted a suite of high-resolution (1500{sup 3} effective) three-dimensional numerical hydrodynamic simulations that follow the evolution of individual clumps as they move into molecular gas. Even at these high resolutions, our simulations do not quite achieve numerical convergence, due to the challenge of properly resolving the small-scale mixing of ejecta and molecular gas, although they do allow some robust conclusions to be drawn. Isotropically exploding ejecta do not penetrate into the molecular cloud or mix with it, but, if cooling is properly accounted for, clumpy ejecta penetrate to distances {approx}10{sup 18} cm and mix effectively with large regions of star-forming molecular gas. In fact, the {approx}2 M{sub Sun} of high-metallicity ejecta from a single core-collapse supernova is likely to mix with {approx}2 Multiplication-Sign 10{sup 4} M{sub Sun} of molecular gas material as it is collapsing. Thus, all stars forming late ( Almost-Equal-To 5 Myr) in the evolution of an H II region may be contaminated by supernova ejecta at the level {approx}10{sup -4}. This level of contamination is consistent with the abundances of short-lived radionuclides and possibly some stable isotopic shifts in the early solar system and is potentially consistent with the observed variability in stellar elemental abundances. Supernova contamination of forming planetary systems may be a common, universal process.

Pan Liubin; Desch, Steven J.; Scannapieco, Evan; Timmes, F. X. [School of Earth and Space Exploration, Arizona State University, P.O. Box 871404, Tempe, AZ 85287-1404 (United States)

2012-09-01

27

The clumpy galaxy Markarian 297 and its supernova activity  

NASA Astrophysics Data System (ADS)

I present radio observations of the clumpy irregular galaxy Mrk 297 (= NGC 6052) made with the Very Large Array (VLA) at 20, 6, 3.6, and 2 cm from 1980 January to 1992 April, which show that the variable, compact source (Mrk 297A) is a single supernova with the highest peak radio luminosity known for a supernova. Twenty-one VLA flux-density measurements at four wavelengths of the compact source, obtained over the past 12 yr, yield a satisfactory fit to Chevalier's model for supernova light curves. Shorter period fluctuations is the observations are significant and are consistent with refractive interstellar scintillation. The supernova rate for the entire galaxy can be estimated from a global formula (Condon & Yin 1990) which uniquely relates total non-thermal radio emission to supernova rate. The resulting supernova rate estimated for the entire galaxy Mrk 297 is high (0.3/yr). However, most individual Type II radio supernovae are too weak to be detected at the distance of Mrk 297.

Yin, Q. F.

1994-01-01

28

DYNAMO Survey: An Upclose View of Clumpy Galaxies  

NASA Astrophysics Data System (ADS)

We highlight recent results on the DYNAMO survey of turbulent, clumpy disks galaxies found at z=0.1. Bright star forming DYNAMO galaxies are found to be very similar in properties to star forming galaxies in the high redshift Universe. Typical star formation rates of turbulent DYNAMO galaxies range 10-80 M ? yr-1. Roughly 2/3 of DYNAMO galaxies have H? kinematics that are consistent with rotation. The typical gas velocity dispersion of DYNAMO galaxies is ? H? ~ 20 - 60 km s-1. We show that, when convolved to the same resolution, maps of H? emission in DYNAMO galaxies have essentially identical morphology as that of z ~ 1 - 3 galaxies. Finally, DYNAMO galaxies have high molecular gas fractions fmol ~ 20 - 35%. We note that DYNAMO galaxies are not dwarfs, typical masses are Mstar ~ 0.8 - 8 × 1010 M?. These data are all consistent with a scenario in which despite being at relatively low redshift the DYNAMO galaxies are forming stars similarly to that observed in the high-redshift Universe, that is to say star formation is occurring in very massive (Mclump ~ 109 M?), very large (rclump ~ 300 pc) clumps of gas.

Fisher, David

2015-02-01

29

How Cold Is Cold?  

NSDL National Science Digital Library

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

Richard Konicek-Moran

2008-04-01

30

Clumpy Galaxies in CANDELS. I. The Definition of UV Clumps and the Fraction of Clumpy Galaxies at 0.5 < z < 3  

NASA Astrophysics Data System (ADS)

Although giant clumps of stars are thought to be crucial to galaxy formation and evolution, the most basic demographics of clumps are still uncertain, mainly because the definition of clumps has not been thoroughly discussed. In this paper, we carry out a study of the basic demographics of clumps in star-forming galaxies at 0.5 < z < 3, using our proposed physical definition that UV-bright clumps are discrete star-forming regions that individually contribute more than 8% of the rest-frame UV light of their galaxies. Clumps defined this way are significantly brighter than the H II regions of nearby large spiral galaxies, either individually or blended, when physical spatial resolution and cosmological dimming are considered. Under this definition, we measure the fraction of star-forming galaxies that have at least one off-center clump (f clumpy) and the contributions of clumps to the rest-frame UV light and star formation rate (SFR) of star-forming galaxies in the CANDELS/GOODS-S and UDS fields, where our mass-complete sample consists of 3239 galaxies with axial ratio q > 0.5. The redshift evolution of f clumpy changes with the stellar mass (M *) of the galaxies. Low-mass (log (M */M ?) < 9.8) galaxies keep an almost constant f clumpy of ~60% from z ~ 3 to z ~ 0.5. Intermediate-mass and massive galaxies drop their f clumpy from 55% at z ~ 3 to 40% and 15%, respectively, at z ~ 0.5. We find that (1) the trend of disk stabilization predicted by violent disk instability matches the f clumpy trend of massive galaxies; (2) minor mergers are a viable explanation of the f clumpy trend of intermediate-mass galaxies at z < 1.5, given a realistic observability timescale; and (3) major mergers are unlikely responsible for the f clumpy trend in all masses at z < 1.5. The clump contribution to the rest-frame UV light of star-forming galaxies shows a broad peak around galaxies with log (M */M ?) ~ 10.5 at all redshifts. The clump contribution in the intermediate-mass and massive galaxies is possibly linked to the molecular gas fraction of the galaxies. The clump contribution to the SFR of star-forming galaxies, generally around 4%-10%, also shows dependence on the galaxy M *, but for a given galaxy M *, its dependence on the redshift is mild.

Guo, Yicheng; Ferguson, Henry C.; Bell, Eric F.; Koo, David C.; Conselice, Christopher J.; Giavalisco, Mauro; Kassin, Susan; Lu, Yu; Lucas, Ray; Mandelker, Nir; McIntosh, Daniel M.; Primack, Joel R.; Ravindranath, Swara; Barro, Guillermo; Ceverino, Daniel; Dekel, Avishai; Faber, Sandra M.; Fang, Jerome J.; Koekemoer, Anton M.; Noeske, Kai; Rafelski, Marc; Straughn, Amber

2015-02-01

31

Sound Absorbers  

NASA Astrophysics Data System (ADS)

Sound absorption indicates the transformation of sound energy into heat. It is, for instance, employed to design the acoustics in rooms. The noise emitted by machinery and plants shall be reduced before arriving at a workplace; auditoria such as lecture rooms or concert halls require a certain reverberation time. Such design goals are realised by installing absorbing components at the walls with well-defined absorption characteristics, which are adjusted for corresponding demands. Sound absorbers also play an important role in acoustic capsules, ducts and screens to avoid sound immission from noise intensive environments into the neighbourhood.

Fuchs, H. V.; Möser, M.

32

A study of the clumpiness in the Monoceros R2 molecular cloud  

NASA Astrophysics Data System (ADS)

The study of clumpiness in the Monoceros R2 molecular cloud, and attempts to investigate the use of dust emission as well as gas tracers to study this, are addressed. A progress in developing the technique of dust temperature distribution by inversion of the emitted spectrum using the Mobius theorem is reported.

1996-04-01

33

Radiative Transfer in a Clumpy Universe. III. The Nature of Cosmological Ionizing Sources  

Microsoft Academic Search

The history of the transition from a neutral intergalactic medium (IGM) to one that is almost fully ionized can reveal the character of cosmological ionizing sources. We study the evolution of the volume filling factors of H II and He III regions in a clumpy IGM and discuss the implications for rival reionization scenarios of the rapid decline observed at

Piero Madau; Francesco Haardt; Martin J. Rees

1999-01-01

34

Common Cold  

MedlinePLUS

... nose, coughing - everyone knows the symptoms of the common cold. It is probably the most common illness. In ... avoid colds. There is no cure for the common cold. For relief, try Getting plenty of rest Drinking ...

35

Common cold  

MedlinePLUS

... are the most common reason that children miss school and parents miss work. Parents often get colds ... other children. A cold can spread quickly through schools or daycares. Colds can occur at any time ...

36

Cold adaptations.  

PubMed

Nowdays, occupational and recreational activities in cold environments are common. Exposure to cold induces thermoregulatory responses like changes of behaviour and physiological adjustments to maintain thermal balance either by increasing metabolic heat production by shivering and/or by decreasing heat losses consecutive to peripheral cutaneous vasoconstriction. Those physiological responses present a great variability among individuals and depend mainly on biometrical characteristics, age, and general cold adaptation. During severe cold exposure, medical disorders may occur such as accidental hypothermia and/or freezing or non-freezing cold injuries. General cold adaptations have been qualitatively classified by Hammel and quantitatively by Savourey. This last classification takes into account the quantitative changes of the main cold reactions: higher or lower metabolic heat production, higher or lesser heat losses and finally the level of the core temperature observed at the end of a standardized exposure to cold. General cold adaptations observed previously in natives could also be developed in laboratory conditions by continuous or intermittent cold exposures. Beside general cold adaptation, local cold adaptation exists and is characterized by a lesser decrease of skin temperature, a more pronounced cold induced vasodilation, less pain and a higher manual dexterity. Adaptations to cold may reduce the occurrence of accidents and improve human performance as surviving in the cold. The present review describes both general and local cold adaptations in humans and how they are of interest for cold workers. PMID:19531907

Launay, Jean-Claude; Savourey, Gustave

2009-07-01

37

Probing clumpy stellar winds with a neutron star  

E-print Network

INTEGRAL, the European Space Agency's gamma-ray observatory, tripled the number of super-giant high-mass X-ray binaries (sgHMXB) known in the Galaxy by revealing absorbed and fast transient (SFXT) systems. In these sources, quantitative constraints on the wind clumping of the massive stars could be obtained from the study of the hard X-ray variability of the compact accreting object. Hard X-ray flares and quiescent emission of SFXT systems have been characterized and used to derive wind clump parameters. A large fraction of the hard X-ray emission is emitted in the form of flares with a typical duration of 3 ks, frequency of 7 days and luminosity of 1E36 erg/s. Such flares are most probably emitted by the interaction of a compact object orbiting at ~10 R* with wind clumps (1E(22-23) g) representing a large fraction of the stellar mass-loss rate. The density ratio between the clumps and the inter-clump medium is 1E(2-4) in SFXT systems. The parameters of the clumps and of the inter-clump medium, derived from the SFXT flaring behavior, are in good agreement with macro-clumping scenario and line driven instability simulations. SFXT have probably a larger orbital radius than classical sgHMXB.

R. Walter; J. Zurita Heras

2007-10-12

38

Probing clumpy stellar winds with a neutron-star  

E-print Network

INTEGRAL tripled the number of super-giant high-mass X-ray binaries (sgHMXB) known in the Galaxy by revealing absorbed and fast transient (SFXT) systems. Quantitative constraints on the wind clumping of massive stars can be obtained from the study of the hard X-ray variability of SFXT. A large fraction of the hard X-ray emission is emitted in the form of flares with a typical duration of 3 ksec, frequency of 7 days and luminosity of 1E36 ergs/s. Such flares are most probably emitted by the interaction of a compact object orbiting at ~ 10 R* with wind clumps (1E(22-23) g) representing a large fraction of the stellar mass-loss rate. The density ratio between the clumps and the inter-clump medium is 1E(2-4) . The parameters of the clumps and of the inter-clump medium, derived from the SFXT flaring behavior, are in good agreement with macro-clumping scenario and line-driven instability simulations. SFXT are likely to have larger orbital radius than classical sgHMXB.

R. Walter; J. Zurita-Heras; J. -C. Leyder

2007-12-12

39

Clumpy and fractal shocks, and the generation of a velocity dispersion in molecular clouds  

E-print Network

We present an alternative explanation for the nature of turbulence in molecular clouds. Often associated with classical models of turbulence, we instead interpret the observed gas dynamics as random motions, induced when clumpy gas is subject to a shock. From simulations of shocks, we show that a supersonic velocity dispersion occurs in the shocked gas provided the initial distribution of gas is sufficiently non-uniform. We investigate the velocity size-scale relation $\\sigma \\propto r^{\\alpha}$ for simulations of clumpy and fractal gas, and show that clumpy shocks can produce realistic velocity size-scale relations with mean $\\alpha \\thicksim 0.5$. For a fractal distribution, with a fractal dimension of 2.2 similar to what is observed in the ISM, we find $\\sigma \\propto r^{0.4}$. The form of the velocity size-scale relation can be understood as due to mass loading, i.e. the post-shock velocity of the gas is determined by the amount of mass encountered as the gas enters the shock. We support this hypothesis with analytical calculations of the velocity dispersion relation for different initial distributions. A prediction of this model is that the line-of sight velocity dispersion should depend on the angle at which the shocked gas is viewed.

Clare Dobbs; Ian Bonnell

2006-10-24

40

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

NASA Astrophysics Data System (ADS)

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.

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

41

Cold Urticaria  

Microsoft Academic Search

\\u000a Cold urticaria is a physical urticaria in which patients experience ­urticaria, angioedema, or both in response to direct\\u000a contact with cold environments, the ingestion of cold beverages or foods, and the handling of cold objects. In this chapter,\\u000a we present two challenging cases of cold urticaria that highlight the diagnostic evaluation and treatment options for these\\u000a patients.

Grace Peace Yu; Alan A. Wanderer; Massoud Mahmoudi

42

Active Absorbers M. Rousseaua  

E-print Network

Introduction An active acoustic absorber must sense the sound field in a room, and generate a signal to absorbActive Absorbers M. Rousseaua and J. Vanderkooyb a B&W Group ltd., Elm Grove Lane, BN44 3SA explores the use of bass loudspeakers as both acoustic sources and broadband absorbers. We develop

Paris-Sud XI, Université de

43

Perfect Metamaterial Absorber  

Microsoft Academic Search

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

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

2008-01-01

44

Common Cold  

NSDL National Science Digital Library

This Web site provides comprehensive information, selected by medical doctors, about the common cold. "The goal is to provide a framework for critical thinking which will allow informed decisions about medical care for the common cold." The section entitled Understanding Colds gives a detailed overview of how the cold virus invades the human body and how cold symptoms are caused. Information about preventing colds, and some of the complications that can occur are also included. The Special Features section includes one of the most interesting parts of the site -- Myths of the Common Cold. This site should be interesting to almost anyone, but perhaps more so for those of us who have recently had a cold.

45

Cold Stress  

MedlinePLUS

... on frostbite and hypothermia. eLCOSH Electronic Library of Construction Occupational Safety & Health (eLCOSH) Cold stress or hypothermia can affect construction workers who are not protected against cold. The ...

46

DYNAMO - II. Coupled stellar and ionized-gas kinematics in two low-redshift clumpy discs  

NASA Astrophysics Data System (ADS)

We study the spatially resolved stellar kinematics of two star-forming galaxies at z ˜ 0.1 from the larger DYnamics of Newly Assembled Massive Objects (DYNAMO) sample. These galaxies, which have been characterized by high levels of star formation and large ionized-gas velocity dispersions, are considered possible analogues to high-redshift clumpy discs. They were observed using the Gemini Multi-Object Spectrograph instrument in integral field spectroscopy (IFS) mode at the Gemini Observatory with high spectral resolution (R ? 5400, equivalent to ? ? 24 km s-1 at the observed wavelengths) and ˜6 h exposure times in order to measure the resolved stellar kinematics via absorption lines. We also obtain higher quality emission-line kinematics than previous observations. The spatial resolution (1.2 kpc) is sufficient to show that the ionized gas in these galaxies (as traced by H? emission) is morphologically irregular, forming multiple giant clumps while stellar continuum light is smooth and well described by an exponential profile. Clumpy gas morphologies observed in IFS data are confirmed by complementary narrow-band H? imaging from the Hubble Space Telescope. Morphological differences between the stars and ionized gas are not reflected dynamically as stellar kinematics are found to be closely coupled to the kinematics of the ionized gas: both components are smoothly rotating with large velocity dispersions (˜40 km s-1) suggesting that the high gas dispersions are not primarily driven by star formation feedback. In addition, the stellar population ages of these galaxies are estimated to be quite young (60-500 Myr). The large velocity dispersions measured for these young stars suggest that we are seeing the formation of thick discs and/or stellar bulges in support of recent models which produce these from clumpy galaxies at high redshift.

Bassett, Robert; Glazebrook, Karl; Fisher, David B.; Green, Andrew W.; Wisnioski, Emily; Obreschkow, Danail; Cooper, Erin Mentuch; Abraham, Roberto G.; Damjanov, Ivana; McGregor, Peter J.

2014-08-01

47

Clumpy Ultracompact HII Regions I: Fully Supersonic Wind-blown Models  

E-print Network

We propose that a significant fraction of the ultracompact HII regions found in massive star-forming clouds are the result of the interaction of the wind and ionizing radiation from a young massive star with the clumpy molecular cloud gas in its neighbourhood. Distributed mass loading in the flow allows the compact nebulae to be long-lived. In this paper, we discuss a particularly simple case, in which the flow in the HII region is everywhere supersonic. The line profiles predicted for this model are highly characteristic, for the case of uniform mass loading. We discuss briefly other observational diagnostics of these models.

J. E. Dyson; R. J. R. Williams; M. P. Redman

1995-07-18

48

Cold streams: detectability, relation to structure and characteristics  

NASA Astrophysics Data System (ADS)

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.

Goerdt, Tobias

2015-02-01

49

Energy-Absorbing, Lightweight Wheels  

NASA Technical Reports Server (NTRS)

Improved energy-absorbing wheels are under development for use on special-purpose vehicles that must traverse rough terrain under conditions (e.g., extreme cold) in which rubber pneumatic tires would fail. The designs of these wheels differ from those of prior non-pneumatic energy-absorbing wheels in ways that result in lighter weights and more effective reduction of stresses generated by ground/wheel contact forces. These wheels could be made of metals and/or composite materials to withstand the expected extreme operating conditions. As shown in the figure, a wheel according to this concept would include an isogrid tire connected to a hub via spring rods. The isogrid tire would be a stiff, lightweight structure typically made of aluminum. The isogrid aspect of the structure would both impart stiffness and act as a traction surface. The hub would be a thin-walled body of revolution having a simple or compound conical or other shape chosen for structural efficiency. The spring rods would absorb energy and partially isolate the hub and the supported vehicle from impact loads. The general spring-rod configuration shown in the figure was chosen because it would distribute contact and impact loads nearly evenly around the periphery of the hub, thereby helping to protect the hub against damage that would otherwise be caused by large loads concentrated onto small portions of the hub.

Waydo, Peter

2003-01-01

50

Fast cold gas in hot AGN outflows  

NASA Astrophysics Data System (ADS)

Observations of the emission from spatially extended cold gas around bright high-redshift quasars (QSOs) reveal surprisingly large velocity widths exceeding 2000 km s- 1, out to projected distances as large as 30 kpc. The high-velocity widths have been interpreted as the signature of powerful AGN-driven outflows. Naively, these findings appear in tension with hydrodynamic models in which AGN-driven outflows are energy-driven and thus very hot with typical temperatures T ? 106-7 K. Using the moving-mesh code AREPO, we perform `zoom-in' cosmological simulations of a z ˜ 6 QSO and its environment, following black hole growth and feedback via energy-driven outflows. In the simulations, the QSO host galaxy is surrounded by a clumpy circumgalactic medium pre-enriched with metals due to supernovae-driven galactic outflows. As a result, part of the AGN-driven hot outflowing gas can cool radiatively, leading to large amounts ( ? 109 M?) of cold gas comoving with the hot bipolar outflow. This results in velocity widths of spatially extended cold gas similar to those observed. We caution, however, that gas inflows, random motions in the deep potential well of the QSO host galaxy and cooling of supernovae-driven winds contribute significantly to the large velocity width of the cold gas in the simulations, complicating the interpretation of observational data.

Costa, Tiago; Sijacki, Debora; Haehnelt, Martin G.

2015-03-01

51

Composition for absorbing hydrogen  

DOEpatents

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.

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

1995-01-01

52

Composition for absorbing hydrogen  

DOEpatents

A hydrogen absorbing composition is described. 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.

Heung, L.K.; Wicks, G.G.; Enz, G.L.

1995-05-02

53

Hot and Cold  

NSDL National Science Digital Library

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.

Oregon Museum of Science and Industry

1997-01-01

54

Shock absorber control system  

SciTech Connect

A shock absorber control system is described for controlling a dampening force of a shock absorber of a vehicle comprising: setting means for setting a desired dampening force changeable within a predetermined range; drive means for driving the shock absorber to change the dampening force of the shock absorber linearly; control means for controlling the drive means in accordance with the desired dampening force when the setting of the desired dampening force has been changed; detecting means for detecting an actual dampening force of the shock absorber; and correcting means for correcting the dampening force of the shock absorber by controlling the drive means in accordance with a difference between the desired dampening force and the detected actual dampening force.

Nakano, Y.; Ohira, M.; Ushida, M.; Miyagawa, T.; Shimodaira, T.

1987-01-13

55

Externally tuned vibration absorber  

DOEpatents

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.

Vincent, Ronald J. (Latham, NY)

1987-09-22

56

Modelling Absorbent Phenomena of Absorbent Structure  

NASA Astrophysics Data System (ADS)

Absorption, retention and strike through time, as evaluating criteria of absorbent structures quality were studied. Determination of influent parameters on these criteria were realized by using the design method of experimental sets. In this study, the studied parameters are: Super absorbent polymer (SAP)/fluff ratio, compression and the porosity of the non woven used as a cover stock. Absorption capacity and retention are mostly influenced by SAP/fluff ratio. However, strike through time is affected by compression. Thus, a modelling of these characteristics in function of the important parameter was established.

Sayeb, S.; Ladhari, N.; Ben Hassen, M.; Sakli, F.

57

Innermost structure and near-infrared radiation of dusty clumpy tori in active galactic nuclei  

NASA Astrophysics Data System (ADS)

The dusty clumpy torus surrounds the central black hole (BH) and the accretion disk in active galactic nuclei, and governs the growth of super-massive BHs via gas fueling towards the central engine. Near-infrared (NIR) monitoring observations have revealed that the torus inner radius is determined by the dust sublimation process. However, the observed radii are systematically smaller than the theoretical predictions by a factor of three. We take into account the anisotropic illumination by the central accretion disk to the torus, and calculate the innermost structure of the torus and the NIR time variability. We then show that the anisotropy naturally solves the systematic discrepancy and that the viewing angle is the primary source to produce an object-to-object scatter of the NIR time delay. Dynamics of clumps at the innermost region of the torus will be unveiled via future high- resolution X-ray spectroscopy (e.g., Astro-H)

Kawaguchi, Toshihiro

2012-12-01

58

On the Relative Mass Column Densities of Giant Star-forming Complexes in Clumpy GOODS Galaxies  

NASA Astrophysics Data System (ADS)

Some galaxies in the HST ACS images of GOODS fields show an extremely clumpy structure, like the clump clusters and chain galaxies we have studied in the UDF. The GOODS galaxies are at lower redshift than the UDF galaxies, and are therefore less subject to morphology corrections due to bandshifting. These lower redshift cases may also show evolutionary trends toward modern spiral galaxies. Here we investigate the ratio of clump mass column density to background disk column density in all of the clump clusters in GOODS. Population synthesis models are used to convert colors and surface brightnesses into age and mass column densities. We compare these ratios to analogous measurements in GOODS spirals. There is a clear trend toward less prominent clumps in spirals than in clump clusters. The large column density ratios in many clump clusters are consistent with our simulations (e.g., Bournaud et al. 2007), which suggest that clumps interact and migrate toward the center to make a bulge.

Elmegreen, Debra M.; Elmegreen, B.; Marcus, M.; Shahinyan, K.; Yau, A.; Petersen, M.

2009-05-01

59

Cold Intolerance  

MedlinePLUS

... of the brain that causes blood vessels to contract, and the hypothalmus, the part that controls the ... message to the capillaries of the skin to contract when it is cold (Bodian, 1949) . Consequently, as ...

60

Electromagnetic shock absorber  

Microsoft Academic Search

This paper introduces a novel passive suspension system for ground vehicles. The system is based a flexible electromagnetic shock absorber (EMSA). In the proposed system, it is attempted: (a) to select a variable high damping coefficient usable in a car; (b) physical dimensions and the geometry of EMSA not to be very different from mechanical shock absorbers; and (c) its

S. Mirzaei; S. M. Saghaiannejad; V. Tahani; M. Moallem

2001-01-01

61

Advanced neutron absorber materials  

DOEpatents

A neutron absorbing material and method utilizing rare earth elements such as gadolinium, europium and samarium to form metallic glasses and/or noble base nano/microcrystalline materials, the neutron absorbing material having a combination of superior neutron capture cross sections coupled with enhanced resistance to corrosion, oxidation and leaching.

Branagan, Daniel J. (Idaho Falls, ID); Smolik, Galen R. (Idaho Falls, ID)

2000-01-01

62

Cold injuries.  

PubMed

Exposure to cold can produce a variety of injuries that occur as a result of man's inability to adapt to cold. These injuries can be divided into localized injury to a body part, systemic hypothermia, or a combination of both. Body temperature may fall as a result of heat loss by radiation, evaporation, conduction, and convection. Hypothermia or systemic cold injury occurs when the core body temperature has decreased to 35 degrees C (95 degrees F) or less. The causes of hypothermia are either primary or secondary. Primary, or accidental, hypothermia occurs in healthy individuals inadequately clothed and exposed to severe cooling. In secondary hypothermia, another illness predisposes the individual to accidental hypothermia. Hypothermia affects multiple organs with symptoms of hypothermia that vary according to the severity of cold injury. The diagnosis of hypothermia is easy if the patient is a mountaineer who is stranded in cold weather. However, it may be more difficult in an elderly patient who has been exposed to a cold environment. In either case, the rectal temperature should be checked with a low-reading thermometer. The general principals of prehospital management are to (1) prevent further heat loss, (2) rewarm the body core temperature in advance of the shell, and (3) avoid precipitating ventricular fibrillation. There are two general techniques of rewarming--passive and active. The mechanisms of peripheral cold injury can be divided into phenomena that affect cells and extracellular fluids (direct effects) and those that disrupt the function of the organized tissue and the integrity of the circulation (indirect effects). Generally, no serious damage is seen until tissue freezing occurs. The mildest form of peripheral cold injury is frostnip. Chilblains represent a more severe form of cold injury than frostnip and occur after exposure to nonfreezing temperatures and damp conditions. Immersion (trench) foot, a disease of the sympathetic nerves and blood vessels in the feet, is observed in shipwreck survivors or in soldiers whose feet have been wet, but not freezing, for long periods. Patients with frostbite frequently present with multisystem injuries (e.g., systemic hypothermia, blunt trauma, substance abuse). The freezing of the corneas has been reported to occur in individuals who keep their eyes open in high wind-chill situations without protective goggles (e.g., snowmobilers, cross-country skiers). PMID:15715518

Long, William B; Edlich, Richard F; Winters, Kathryne L; Britt, L D

2005-01-01

63

Internal absorber solar collector  

DOEpatents

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 elevation angle by 120.degree. or more in the azimuth sectors with a collector concentration ratio of approximately 3.0. Miniaturized construction of the circular dielectric rods with internal absorbers reduces the weight per area of glass, plastic and metal used in the collector panels. No external parts or insulation are needed as heat losses are low due to partial vacuum or low conductivity gas surrounding heated portions of the collector. The miniature internal absorbers are generally made of solid copper with black selective surface and the collected solar heat is extracted at the collector ends by thermal conductivity along the absorber rods. Heat is removed from end fittings by use of liquid circulants. Several alternate constructions are provided for simplifying collector panel fabrication and for preventing the thermal expansion and contraction of the heated absorber or circulant tubes from damaging vacuum seals. In a modified version of the internal absorber collector, oil with temperature dependent viscosity is pumped through a segmented absorber which is now composed of closely spaced insulated metal tubes. In this way the circulant is automatically diverted through heated portions of the absorber giving higher collector concentration ratios than theoretically possible for an unsegmented absorber.

Sletten, Carlyle J. (106 Nagog Hill Rd., Acton, MA 01720); Herskovitz, Sheldon B. (88 Hammond St., Acton, MA 01720); Holt, F. S. (46 Emerson Rd., Winchester, MA 01890); Sletten, E. J. (Chestnut Hill Rd. R.F.D. Rte. #4, Amherst, NH 03031)

1981-01-01

64

Drill string shock absorber  

SciTech Connect

A telescopic shock absorber for use in a drill string includes a resilient arrangement to cushion telescopic contraction and extension of the shock absorber in response to shock loads and vibrations imparted during drilling. The shock absorber operates independently of the drilling fluid pressure conducted through the structure during drilling operations. A dampening system assists in cushioning the shock loads and vibrations and the dampening system and resilient arrangement are deactivated when jarring impacts are delivered to the well string by a drilling jar carried therein. The resilient arrangement provides a combination mechanical and hydraulic system for cushioning the impact loads and vibrations encountered.

Anderson, E. A.; Webb, D. D.

1985-11-12

65

Lipid-absorbing Polymers  

NASA Technical Reports Server (NTRS)

The removal of bile acids and cholesterol by polymeric absorption is discussed in terms of micelle-polymer interaction. The results obtained with a polymer composed of 75 parts PEO and 25 parts PB plus curing ingredients show an absorption of 305 to 309%, based on original polymer weight. Particle size effects on absorption rate are analyzed. It is concluded that crosslinked polyethylene oxide polymers will absorb water, crosslinked polybutadiene polymers will absorb lipids; neither polymer will absorb appreciable amounts of lipids from micellar solutions of lipids in water.

Marsh, H. E., Jr.; Wallace, C. J.

1973-01-01

66

Cold Metal  

NSDL National Science Digital Library

In this activity, learners discover that our hands are not reliable thermometers. Learners place their palms flat on various surfaces (metal, wood, glass, etc.) and compare how cold the surfaces feel. Learners are challenged to arrange the materials in order from cold to warm. Then, they use a thermometer to measure the temperature of each surface, only to discover that the surfaces are all at the same temperature. Use this activity to talk about temperature-sensitive nerves in skin as well as how different materials act as insulators and conductors of heat.

2012-01-30

67

Absorbance modulation optical lithography  

E-print Network

In this thesis, the concept of absorbance-modulation optical lithography (AMOL) is described, and the feasibility experimentally verified. AMOL is an implementation of nodal lithography, which is not bounded by the diffraction ...

Tsai, Hsin-Yu Sidney

2007-01-01

68

"Smart" Electromechanical Shock Absorber  

NASA Technical Reports Server (NTRS)

Shock-absorbing apparatus includes electromechanical actuator and digital feedback control circuitry rather than springs and hydraulic damping as in conventional shock absorbers. Device not subject to leakage and requires little or no maintenance. Attenuator parameters adjusted in response to sensory feedback and predictive algorithms to obtain desired damping characteristic. Device programmed to decelerate slowly approaching vehicle or other large object according to prescribed damping characteristic.

Stokes, Lebarian; Glenn, Dean C.; Carroll, Monty B.

1989-01-01

69

Auxiliary shock absorber assembly  

SciTech Connect

This patent describes an auxiliary shock absorber assembly adapted to be secured to the frame of a vehicle and to the vehicle suspension system for providing additional shock absorption in the event of the vehicle impacts an irregularity in the roadway. The assembly comprises a shock absorber having a piston rod extending from one end and includes means disposed for biasing the piston rod outwardly; means carried by the shock absorber for securing the shock absorber to the frame of the vehicle such that the piston rod extends downwardly, a first stop member carried by to the piston rod adjacent the end. A second stop member carries by the piston rod and spaced from the first stop member; and a bracket assembly defining means for securing the bracket assembly to the vehicle suspension system and means for slidably receiving the portion of the piston rod disposed between the stop members. The shock absorber is secured to the frame of the vehicle and the bracket to the vehicle suspension system with the piston rod slideably through assembly between the stop members. Sufficient upward movement of the vehicle suspension system responds to the vehicle impacting an irregularity in the roadway causing the bracket assembly to abut the second stop member and urge the piston rod into the shock absorber providing additional shock absorbtion for the vehicle.

Hetherington, T.G.

1987-07-07

70

Clumpy ultracompact HII regions -- II. Cores, spheres and shells from subsonic flows  

E-print Network

We have modelled ultracompact HII regions (UCHIIR) in terms of steady subsonic ionized flows in a clumpy medium. Mass loss from neutral clumps allows the regions to be long-lived. We examine the form of global flows for different dependences of the volume mass injection rate, $\\dot{q}$, on radius and Mach number, and describe the solutions in detail. We find that three observed UCHIIR morphologies are reproduced with these models. Mach number independent flows that include a radial variation can give centre- brightened core--halo morphologies. Mach number dependent flows reproduce naturally the uniform UCHIIR morphology. In a hybrid model, including subsonic and supersonic flows, we allow a supersonic wind to shock in the ionized region. The ionized subsonic gas has a high density and so dominates the emission. The shell produced has a velocity structure very different from that of fully supersonic models. Several morphologies of spherical UCHIIR can be understood in terms of these various models; however, kinematic data are crucial as a discriminant between them.

M. P. Redman; R. J. R. Williams; J. E. Dyson

1996-03-01

71

Magnification Probability Distribution Functions of Standard Candles in a Clumpy Universe  

E-print Network

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.

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

2008-11-28

72

Far-infrared observations of M17SW - The clumpy structure of the photodissociation region  

NASA Technical Reports Server (NTRS)

Forbidden O I 63-micron and forbidden Si II 35-micron fine-structure line emission in M17SW was mapped, and the intensities of the forbidden O I 63 and 146 microns, forbidden Si II 35 microns, and forbidden C II 158 microns were measured at four positions. New 50- and 100-micron continuum maps of the M17SW cloud at comparable resolution to the FIR line observations are presented. Analysis in terms of a homogeneous model yields an incident UV field of 56,000 habings, a density of 30,000 cu cm, and a temperature of about 300 K for the atomic gas. It is concluded that the M17SW photodissociation region is clumpy in nature. The observed forbidden Si II and high-J CO imply the presence of high-density clumps. The clumps dominate the emission in the forbidden O I, Si II, and high-level CO lines, while the forbidden C II, C I, and low-level CO arise mostly in the interclump gas. The extended (about 15 pc) forbidden C II and forbidden C I emission is attributed to the halo gas.

Meixner, Margaret; Haas, Michael R.; Tielens, A. G. G. M.; Erickson, E. F.; Werner, M.

1992-01-01

73

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

NASA Astrophysics Data System (ADS)

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).

Ohnaka, K.

2014-08-01

74

Hot, Cold, and Really Cold.  

ERIC Educational Resources Information Center

Describes a physics experiment investigating temperature prediction and the relationship between the physical properties of heat units, melting, dissolving, states of matter, and energy loss. Details the experimental setup, which requires hot and cold water, a thermometer, and ice. Notes that the experiment employs a deliberate counter-intuitive…

Leyden, Michael

1997-01-01

75

Shock absorber servicing tool  

NASA Technical Reports Server (NTRS)

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.

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

1981-01-01

76

Multiple-layer Radiation Absorber  

NASA Astrophysics Data System (ADS)

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.

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

77

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

SciTech Connect

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.

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

78

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

SciTech Connect

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.

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

79

Evidence for a Clumpy, Rotating Gas Disk in a Submillimeter Galaxy at z = 4  

NASA Astrophysics Data System (ADS)

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 × 1011 M ?. We use this dynamical mass estimate to constrain the CO-to-H2 mass conversion factor (?CO), finding ?CO = 1.1 ± 0.6 M ?(K km s-1 pc2)-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 × (?CO/0.8) M ? pc-2. Virial mass estimates indicate they could be self-gravitating, and we constrain their CO-to-H2 mass conversion factor to be <0.2-0.7 M ?(K km s-1 pc2)-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.

Hodge, J. A.; Carilli, C. L.; Walter, F.; de Blok, W. J. G.; Riechers, D.; Daddi, E.; Lentati, L.

2012-11-01

80

Confronting the Evolving Clumpy Shell Structure of IRC +10216 with Time Dependent Dust Shell Models  

NASA Astrophysics Data System (ADS)

The prototypical dust enshrouded carbon Mira IRC +10216 is known to exhibit intrinsic structural changes on a time scale of the order of 10 yr as revealed, e.g., by CO infrared line profiles, its infrared light curves, or by high spatial resolution monitoring in the infrared. In particular, the light curves obtained over 35 yr indicate a possible periodicity on a ? 20 yr time scale, which suggests that a recurrent phenomenon might lead to the observed variations in the CO first overtone line profiles and the clumpy spatial structure. Such multi-periodicity time scales, which correspond to several (? 10) pulsation periods of the star, are predicted by consistent hydrodynamical models which include a proper treatment of dust formation. In these models discrete dust layers form on a time scale which is longer than the typical pulsation period of AGB stars (Fleischer et al. 1995). In the high spatial resolution images of IRC +10216 (Osterbart et al. 2000) several components can be identified, whose structure and brightness evolve considerably within only a few years. To shed some light on this evolution, we apply a spherically symmetric, time-dependent dust shell model which consistently describes the coupled system of hydrodynamics, chemistry, dust formation and radiative transfer (Winters et al. 2000) and confront the kinematics and brightness variations predicted by this model with the high spatial resolution observations of IRC +10216. Fleischer A.J., Gauger A., Sedlmayr E., 1995, A&A 297, 543 Osterbart R., Balega Y.Y., Blöcker T., et al., 2000, A&A 357, 169 Winters J.M., Le Bertre T., Jeong K.S., et al., 2000, A&A 361, 641

Winters, J. M.; Blöcker, T.; Hofmann, K.-H.; Weigelt, G.

81

Solar concentrator/absorber  

NASA Technical Reports Server (NTRS)

Collector/energy converter, consisting of dual-slope optical concentrator and counterflow thermal energy absorber, is attached to multiaxis support structure. Efficient over wide range of illumination levels, device may be used to generate high temperature steam, serve as solar powered dryer, or power absorption cycle cooler.

Von Tiesenhausen, G. F.

1976-01-01

82

Neutron Absorbing Alloys  

DOEpatents

The present invention is drawn to new classes of advanced neutron absorbing structural materials for use in spent nuclear fuel applications requiring structural strength, weldability, and long term corrosion resistance. Particularly, an austenitic stainless steel alloy containing gadolinium and less than 5% of a ferrite content is disclosed. Additionally, a nickel-based alloy containing gadolinium and greater than 50% nickel is also disclosed.

Mizia, Ronald E. (Idaho Falls, ID); Shaber, Eric L. (Idaho Falls, ID); DuPont, John N. (Whitehall, PA); Robino, Charles V. (Albuquerque, NM); Williams, David B. (Bethlehem, PA)

2004-05-04

83

Absorber for dehydrating gas  

Microsoft Academic Search

An improved absorber is claimed for extracting water or other liquid contaminants contained in gas including an upright vessel having a gas and a desiccant inlet; a gas outlet adjacent the top and a liquid desiccant outlet adjacent the bottom; a horizontal plate separating the interior of the vessel into an upper and lower chamber; a vertical mixing conduit within

J. D. Honerkamp; H. O. Ebeling

1984-01-01

84

Cold Sores  

NSDL National Science Digital Library

This patient education program explains cold sores. It reviews signs, stages, infection, outbreaks, diagnosis and treatment options, as well as self-care and prevention. This is a MedlinePlus Interactive Health Tutorial from the National Library of Medicine, designed and developed by the Patient Education Institute. NOTE: The tutorial requires a special Flash plug-in, version 4 or above. If you do not have Flash, you will be prompted to obtain a free download of the software before you start the tutorial. You will also need an Acrobat Reader, available as a free download, in order to view the Reference Summary.

Patient Education Institute

85

Broadband plasma absorber  

Microsoft Academic Search

Summary form only given, as follows. A tenuous plasma generated in a background gas at atmospheric pressure is highly collisional. The cold collisional dispersion relation was used to model electromagnetic effects. For a plasma generated by a point source such as an ultraviolet flash lamp the electron number density decreases as a function of distance from the source. An Epstein

R. J. Vidmar

1990-01-01

86

Apollo couch energy absorbers  

NASA Technical Reports Server (NTRS)

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.

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

1972-01-01

87

Time resolved spectroscopy of GRB 021004 reveals a clumpy extended wind  

E-print Network

High resolution spectroscopy of GRB 021004 revealed a wealth of absorption lines from several intermediate ionization species. The velocity structure of the absorber is complex and material with velocity up to >3000 km/s is observed. Since only the blueshifted component is observed, the absorber is very likely to be material closely surrounding the gamma-ray burst. We use a time-dependent photoionization code to track the abundance of the ions over time. Thanks to the presence of absorption from intermediate ionization states at long times, we can estimate the location and mass of the components of the absorber. We interpret those constraints within the hypernova scenario showing that the mass loss rate of the progenitor must have been ~10^{-4} solar masses per year, suggestive of a very massive star. In addition, the wind termination shock must lie at a distance of at least 100 pc, implying a low density environment. The velocity structure of the absorber also requires clumping of the wind at those large distances.

D. Lazzati; R. Perna; J. Flasher; V. Dwarkadas; F. Fiore

2006-08-21

88

No More Active Galactic Nuclei in Clumpy Disks Than in Smooth Galaxies at z ~ 2 in CANDELS/3D-HST  

NASA Astrophysics Data System (ADS)

We use CANDELS imaging, 3D-HST spectroscopy, and Chandra X-ray data to investigate if active galactic nuclei (AGNs) are preferentially fueled by violent disk instabilities funneling gas into galaxy centers at 1.3 < z < 2.4. We select galaxies undergoing gravitational instabilities using the number of clumps and degree of patchiness as proxies. The CANDELS visual classification system is used to identify 44 clumpy disk galaxies, along with mass-matched comparison samples of smooth and intermediate morphology galaxies. We note that despite being mass-matched and having similar star formation rates, the smoother galaxies tend to be smaller disks with more prominent bulges compared to the clumpy galaxies. The lack of smooth extended disks is probably a general feature of the z ~ 2 galaxy population, and means we cannot directly compare with the clumpy and smooth extended disks observed at lower redshift. We find that z ~ 2 clumpy galaxies have slightly enhanced AGN fractions selected by integrated line ratios (in the mass-excitation method), but the spatially resolved line ratios indicate this is likely due to extended phenomena rather than nuclear AGNs. Meanwhile, the X-ray data show that clumpy, smooth, and intermediate galaxies have nearly indistinguishable AGN fractions derived from both individual detections and stacked non-detections. The data demonstrate that AGN fueling modes at z ~ 1.85—whether violent disk instabilities or secular processes—are as efficient in smooth galaxies as they are in clumpy galaxies. 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.

Trump, Jonathan R.; Barro, Guillermo; Juneau, Stéphanie; Weiner, Benjamin J.; Luo, Bin; Brammer, Gabriel B.; Bell, Eric F.; Brandt, W. N.; Dekel, Avishai; Guo, Yicheng; Hopkins, Philip F.; Koo, David C.; Kocevski, Dale D.; McIntosh, Daniel H.; Momcheva, Ivelina; Faber, S. M.; Ferguson, Henry C.; Grogin, Norman A.; Kartaltepe, Jeyhan; Koekemoer, Anton M.; Lotz, Jennifer; Maseda, Michael; Mozena, Mark; Nandra, Kirpal; Rosario, David J.; Zeimann, Gregory R.

2014-10-01

89

SHOCKED SUPERWINDS FROM THE z {approx} 2 CLUMPY STAR-FORMING GALAXY, ZC406690  

SciTech Connect

We have obtained high-resolution data of the z {approx} 2 ring-like, clumpy star-forming galaxy (SFG) ZC406690 using the VLT/SINFONI with adaptive optics (in K band) and in seeing-limited mode (in H and J bands). Our data include all of the main strong optical emission lines: [O II], [O III], H{alpha}, H{beta}, [N II], and [S II]. We find broad, blueshifted H{alpha} and [O III] emission line wings in the spectra of the galaxy's massive, star-forming clumps ({sigma} {approx} 85 km s{sup -1}) and even broader wings (up to 70% of the total H{alpha} flux, with {sigma} {approx} 290 km s{sup -1}) in regions spatially offset from the clumps by {approx}2 kpc. The broad emission likely originates from large-scale outflows with mass outflow rates from individual clumps that are 1-8 Multiplication-Sign the star formation rate (SFR) of the clumps. Based on emission line ratio diagnostics ([N II]/H{alpha} and [S II]/H{alpha}) and photoionization and shock models, we find that the emission from the clumps is due to a combination of photoionization from the star-forming regions and shocks generated in the outflowing component, with 5%-30% of the emission deriving from shocks. In terms of the ionization parameter (6 Multiplication-Sign 10{sup 7} to 10{sup 8} cm s{sup -1}, based on both the SFR and the O{sub 32} ratio), density (local electron densities of 300-1800 cm{sup -3} in and around the clumps, and ionized gas column densities of 1200-8000 M{sub Sun }pc{sup -2}), and SFR (10-40 M{sub Sun} yr{sup -1}), these clumps more closely resemble nuclear starburst regions of local ultraluminous infrared galaxies and dwarf irregulars than H II regions in local galaxies. However, the star-forming clumps are not located in the nucleus as in local starburst galaxies but instead are situated in a ring several kpc from the center of their high-redshift host galaxy, and have an overall disk-like morphology. The two brightest clumps are quite different in terms of their internal properties, energetics, and relative ages, and thus we are given a glimpse at two different stages in the formation and evolution of rapidly star-forming giant clumps at high-z.

Newman, Sarah F.; Genzel, Reinhard [Department of Astronomy, Campbell Hall, University of California, Berkeley, CA 94720 (United States); Shapiro Griffin, Kristen [Aerospace Research Laboratories, Northrop Grumman Aerospace Systems, Redondo Beach, CA 90278 (United States); Davies, Ric; Foerster-Schreiber, Natascha M.; Tacconi, Linda J.; Kurk, Jaron; Wuyts, Stijn; Genel, Shy; Buschkamp, Peter; Eisenhauer, Frank; Lutz, Dieter [Max-Planck-Institut fuer extraterrestrische Physik (MPE), Giessenbachstr.1, D-85748 Garching (Germany); Lilly, Simon J.; Carollo, C. Marcella [Institute of Astronomy, Department of Physics, Eidgenoessische Technische Hochschule, ETH Zuerich CH-8093 (Switzerland); Renzini, Alvio; Mancini, Chiara [Osservatorio Astronomico di Padova, Vicolo dellOsservatorio 5, Padova I-35122 (Italy); Bouche, Nicolas [Department of Physics and Astronomy, University of California, Santa Barbara, Santa Barbara, CA 93106 (United States); Burkert, Andreas [Department fuer Physik, Universitaets-Sternwarte Ludwig-Maximilians-Universitaet (USM), Scheinerstr. 1, Muenchen, D-81679 (Germany); Cresci, Giovanni [Istituto Nazionale di AstrofisicaOsservatorio Astronomico di Arcetri, Largo Enrico Fermi 5, I 50125 Firenze (Italy); Hicks, Erin, E-mail: sfnewman@berkeley.edu [Department of Astronomy, University of Washington, Box 351580, U.W., Seattle, WA 98195-1580 (United States); and others

2012-06-20

90

Corrosion resistant neutron absorbing coatings  

DOEpatents

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.

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

2013-11-12

91

Corrosion resistant neutron absorbing coatings  

DOEpatents

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.

Choi, Jor-Shan (El Cerrito, CA); Farmer, Joseph C. (Tracy, CA); Lee, Chuck K. (Hayward, CA); Walker, Jeffrey (Gaithersburg, MD); Russell, Paige (Las Vegas, NV); Kirkwood, Jon (Saint Leonard, MD); Yang, Nancy (Lafayette, CA); Champagne, Victor (Oxford, PA)

2012-05-29

92

Electron beam standby absorber system  

NASA Technical Reports Server (NTRS)

Electron beam energy is absorbed by deflectors which allow beam distribution over an absorber located between the deflectors and workpiece. The undeflected beam passes through a hole in the absorber when the deflection is de-energized, when energized, the beam is kept to a minimum power level by deflection rate change.

Downing, R. D.

1968-01-01

93

Low temperature selective absorber research  

Microsoft Academic Search

Research carried out since 1979 on selective absorbers is surveyed, with particular attention given to the low-temperature coatings seen as promising for flat plate and evacuated tube applications. The most thoroughly investigated absorber is black chrome, which is highly selective and is the most durable low-temperature absorber. It is believed that other materials, because of their low cost and lower

S. A. Herzenberg; R. Silberglitt

1982-01-01

94

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

NASA Astrophysics Data System (ADS)

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.

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

95

Bronchitis (Chest Cold)  

MedlinePLUS

... Antibiotic Use Respiratory Illnesses Sinus Infection Sore Throat Common Cold and Runny Nose Ear Infections Bronchitis (Chest Cold) ... Tips Appropriate Treatment Summary Cough Illness/Bronchitis The Common Cold Otitis Media Pharyngitis: Treat Only Proven GAS Online ...

96

Cold knife cone biopsy  

MedlinePLUS

A cold knife cone biopsy (conization) is surgery to remove a sample of abnormal tissue from the cervix. The cervix is ... Cold knife cone biopsy is done to detect cervical cancer or early changes that lead to cancer. A cold ...

97

Underwater acoustic omnidirectional absorber  

NASA Astrophysics Data System (ADS)

Gradient index media, which are designed by varying local element properties in given geometry, have been utilized to manipulate acoustic waves for a variety of devices. This study presents a cylindrical, two-dimensional acoustic "black hole" design that functions as an omnidirectional absorber for underwater applications. The design features a metamaterial shell that focuses acoustic energy into the shell's core. Multiple scattering theory was used to design layers of rubber cylinders with varying filling fractions to produce a linearly graded sound speed profile through the structure. Measured pressure intensity agreed with predicted results over a range of frequencies within the homogenization limit.

Naify, Christina J.; Martin, Theodore P.; Layman, Christopher N.; Nicholas, Michael; Thangawng, Abel L.; Calvo, David C.; Orris, Gregory J.

2014-02-01

98

Absorbed dose water calorimeter.  

PubMed

Advantage was taken of the low thermal diffusivity of water and the imperviousness of polyethylene film to water to construct a calorimeter for directly measuring absorbed dose in that medium. An ultrasmall bead thermistor was sandwiched between two thin films stretched on polystyrene rings and immersed in an unregulated water bath. Ten cobalt-60 irradiation runs were made with a precision of 0.5% mean error of the mean at a dose rate of 66 mGy/s. Further development is directed toward a standard instrument that can be used in a medical therapy beam. PMID:7382919

Domen, S R

1980-01-01

99

Cold Atoms  

NASA Astrophysics Data System (ADS)

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.

Bellac, Michel Le

2014-11-01

100

Sensing with THz metamaterial absorbers  

E-print Network

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...

Cong, Longqing

2014-01-01

101

Metamaterial saturable absorber mirror.  

PubMed

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

Dayal, Govind; Ramakrishna, S Anantha

2013-02-01

102

HYPOTHERMIA Surviving the Cold  

E-print Network

), and fatigue are some of the main factors that can contribute to hypothermia. · Cold is the most common causeHYPOTHERMIA 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

Machel, Hans

103

Absorber coatings' degradation  

SciTech Connect

This report is intended to document some of the Los Alamos efforts that have been carried out under the Department of Energy (DOE) Active Heating and Cooling Materials Reliability, Maintainability, and Exposure Testing program. Funding for these activities is obtained directly from DOE although they represent a variety of projects and coordination with other agencies. Major limitations to the use of solar energy are the uncertain reliability and lifetimes of solar systems. This program is aimed at determining material operating limitations, durabilities, and failure modes such that materials improvements can be made and lifetimes can be extended. Although many active and passive materials and systems are being studied at Los Alamos, this paper will concentrate on absorber coatings and degradation of these coatings.

Moore, S.W.

1984-01-01

104

Absorber for dehydrating gas  

SciTech Connect

An improved absorber is claimed for extracting water or other liquid contaminants contained in gas including an upright vessel having a gas and a desiccant inlet; a gas outlet adjacent the top and a liquid desiccant outlet adjacent the bottom; a horizontal plate separating the interior of the vessel into an upper and lower chamber; a vertical mixing conduit within the vessel connected at its upper end with the vessel gas and desiccant inlets and passing downwardly through an opening in the plate, the vertical mixing conduit having a mixer element therein which intimately co-mingles the gas and liquid desiccant as they pass into the vessel and downwardly through the mixing conduit into the vessel lower chamber; a plurality of vertical cylindrical members supported in openings in the horizontal plate, the lower end extending below the plate and the upper end extending above the plate; a cap covering the upper portion of each of the cylindrical members, each cap having passageways in the lower edges thereof so that gas and liquid can flow upwardly through the vertical cylindrical members and under the caps and into the vessel upper chamber; packing within the vessel upper chamber, the lower chamber and the lower portion of the upper chamber having the packing therein being filled with liquid desiccant and means of maintaining the level of liquid desiccant and withdrawing the desiccant from the vessel so as to maintain the preselected level, the gas passing out the gas outlet in the upper portion of the vessel and the water in the gas being absorbed by the liquid desiccant and carried out of the vessel with the desiccant.

Honerkamp, J.D.; Ebeling, H.O.

1984-06-19

105

Broadband patterned magnetic microwave absorber  

SciTech Connect

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.

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

106

Electrochemically regenerable carbon dioxide absorber  

NASA Technical Reports Server (NTRS)

Preliminary designs were generated for two electrochemically regenerable carbon dioxide absorber concepts. Initially, an electrochemically regenerable absorption bed concept was designed. This concept incorporated the required electrochemical regeneration components in the absorber design, permitting the absorbent to be regenerated within the absorption bed. This hardware was identified as the electrochemical absorber hardware. The second hardware concept separated the functional components of the regeneration and absorption process. This design approach minimized the extravehicular activity component volume by eliminating regeneration hardware components within the absorber. The electrochemical absorber hardware was extensively characterized for major operating parameters such as inlet carbon dioxide partial pressure, process air flow rate, operational pressure, inlet relative humidity, regeneration current density and absorption/regeneration cycle endurance testing.

Woods, R. R.; Marshall, R. D.; Schubert, F. H.; Heppner, D. B.

1979-01-01

107

Broadband patterned magnetic microwave absorber  

NASA Astrophysics Data System (ADS)

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.

Li, Wei; Wu, Tianlong; Wang, Wei; Zhai, Pengcheng; Guan, Jianguo

2014-07-01

108

Plants absorb heavy metals  

SciTech Connect

Decontamination of heavy metals-polluted soils remains one of the most intractable problems of cleanup technology. Currently available techniques include extraction of the metals by physical and chemical means, such as acid leaching and electroosmosis, or immobilization by vitrification. There are presently no techniques for cleanup which are low cost and retain soil fertility after metals removal. But a solution to the problem could be on the horizon. A small but growing number of plants native to metalliferous soils are known to be capable of accumulating extremely high concentrations of metals in their aboveground portions. These hyperaccumulators, as they are called, contain up to 1,000 times larger metal concentrations in their aboveground parts than normal species. Their distribution is global, including many different families of flowering plants of varying growth forms, from herbaceous plants to trees. Hyperaccumulators absorb metals they do not need for their own nutrition. The metals are accumulated in the leaf and stem vacuoles, and to a lesser extent in the roots.

Parry, J.

1995-02-01

109

Improvement Of The Helmholtz Absorber  

NASA Technical Reports Server (NTRS)

Helmholtz-resonator system improved to enable it to absorb sound at more than one frequency without appreciable loss of effectiveness at primary frequency. Addition of annular cavities enables absorption of sound at harmonic frequencies in addition to primary frequency. Improved absorber designed for use on structures of high transmission loss. Applied to such machines as fixed-speed engines and fans.

Morrow, Duane L.

1992-01-01

110

Black liquid absorbing solar collector  

Microsoft Academic Search

A description is given of a solar to thermal energy converter for use in solar energy collector systems comprising an upper and lower surfaces transparent to solar energy and defining a plurality of elongate channel means therebetween for exposing a solar energy absorber heat transfer fluid to solar radiation, a solar energy absorber heat transfer fluid comprisng a black liquid

Mattson

1980-01-01

111

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

E-print Network

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...

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

112

Cold Stress and the Cold Pressor Test  

ERIC Educational Resources Information Center

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…

Silverthorn, Dee U.; Michael, Joel

2013-01-01

113

Leaf absorbance and photosynthesis  

NASA Technical Reports Server (NTRS)

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.

Schurer, Kees

1994-01-01

114

Vitamin C and colds  

MedlinePLUS

... popular belief that vitamin C can cure the common cold , the scientific evidence for this is conflicting. Large ... B. Vitamin C for preventing and treating the common cold. Cochrane Database Syst Rev . 2007 Jul 18;(3): ...

115

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 - ...

116

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

NASA Technical Reports Server (NTRS)

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.

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

1982-01-01

117

thin films as absorber  

NASA Astrophysics Data System (ADS)

Photovoltaic structures were prepared using AgSb(S x Se1- x )2 as absorber and CdS as window layer at various conditions via a hybrid technique of chemical bath deposition and thermal evaporation followed by heat treatments. Silver antimony sulfo selenide thin films [AgSb(S x Se1- x )2] were prepared by heating multilayers of sequentially deposited Sb2S3/Ag dipped in Na2SeSO3 solution, glass/Sb2S3/Ag/Se. For this, Sb2S3 thin films were deposited from a chemical bath containing SbCl3 and Na2S2O3. Then, Ag thin films were thermally evaporated on glass/Sb2S3, followed by selenization by dipping in an acidic solution of Na2SeSO3. The duration of dipping was varied as 3, 4 and 5 h. Two different heat treatments, one at 350 °C for 20 min in vacuum followed by a post-heat treatment at 325 °C for 2 h in Ar, and the other at 350 °C for 1 h in Ar, were applied to the multilayers of different configurations. X-ray diffraction results showed the formation of AgSb(S x Se1- x )2 thin films as the primary phase and AgSb(S,Se)2 and Sb2S3 as secondary phases. Morphology and elemental detection were done by scanning electron microscopy and energy dispersive X-ray analysis. X-ray photoelectron spectroscopic studies showed the depthwise composition of the films. Optical properties were determined by UV-vis-IR transmittance and reflection spectral analysis. AgSb(S x Se1- x )2 formed at different conditions was incorporated in PV structures glass/FTO/CdS/AgSb(S x Se1- x )2/C/Ag. Chemically deposited post-annealed CdS thin films of various thicknesses were used as window layer. J- V characteristics of the cells were measured under dark and AM1.5 illumination. Analysis of the J- V characteristics resulted in the best solar cell parameters of V oc = 520 mV, J sc = 9.70 mA cm-2, FF = 0.50 and ? = 2.7 %.

González, J. O.; Shaji, S.; Avellaneda, D.; Castillo, G. A.; Das Roy, T. K.; Krishnan, B.

2014-09-01

118

Exercising in Cold Weather  

MedlinePLUS

... www.nia.nih.gov/Go4Life Exercising in Cold Weather Exercise has benefits all year, even during winter. ... activities when it’s cold outside: l Check the weather forecast. If it’s very windy or cold, exercise ...

119

Self-Regulating Shock Absorber  

NASA Technical Reports Server (NTRS)

Mechanical shock absorber keeps frictional damping force within tolerable limit. Its damping force does not increase with coefficient of friction between energy-absorbing components; rather, frictional damping force varies only slightly. Relatively insensitive to manufacturing variations and environmental conditions altering friction. Does not exhibit high breakaway friction and consequent sharp increase followed by sharp decrease in damping force at beginning of stroking. Damping force in absorber does not vary appreciably with speed of stroking. In addition, not vulnerable to leakage of hydraulic fluid.

Wesselski, Clarence J.

1995-01-01

120

Hypothermia: A Cold Weather Hazard  

MedlinePLUS

... cold air. But, not everyone knows that cold weather can also lower the temperature inside your body. ... cold it is where you are. Check the weather forecasts for windy and cold weather. Try to ...

121

Review in Sound Absorbing Materials  

Microsoft Academic Search

This article is a bibliographical revision concerning acoustic absorbing materials, also known as poroelastics. These absorbing\\u000a materials are a passive medium use extensively in the industry to reduce noise. This review presents the fundamental parameters\\u000a that define each of the parts comprising these materials, as well as current experimental methods used to measure said parameters.\\u000a Further along, we will analyze

X. Sagartzazu; L. Hervella-Nieto; J. M. Pagalday

2007-01-01

122

Hyperuniformity of Critical Absorbing States  

NASA Astrophysics Data System (ADS)

The properties of the absorbing states of nonequilibrium models belonging to the conserved directed percolation universality class are studied. We find that, at the critical point, the absorbing states are hyperuniform, exhibiting anomalously small density fluctuations. The exponent characterizing the fluctuations is measured numerically, a scaling relation to other known exponents is suggested, and a new correlation length relating to this ordering is proposed. These results may have relevance to photonic band-gap materials.

Hexner, Daniel; Levine, Dov

2015-03-01

123

Countercurrent flow absorber and desorber  

DOEpatents

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.

Wilkinson, W.H.

1984-10-16

124

21 CFR 872.6050 - Saliva absorber.  

Code of Federal Regulations, 2010 CFR

... 2010-04-01 2010-04-01 false Saliva absorber. 872.6050 Section 872.6050...DEVICES Miscellaneous Devices § 872.6050 Saliva absorber. (a) Identification. A saliva absorber is a device made of paper or...

2010-04-01

125

21 CFR 872.6050 - Saliva absorber.  

Code of Federal Regulations, 2011 CFR

... 2011-04-01 2011-04-01 false Saliva absorber. 872.6050 Section 872.6050...DEVICES Miscellaneous Devices § 872.6050 Saliva absorber. (a) Identification. A saliva absorber is a device made of paper or...

2011-04-01

126

21 CFR 872.6050 - Saliva absorber.  

Code of Federal Regulations, 2014 CFR

... 2014-04-01 2014-04-01 false Saliva absorber. 872.6050 Section 872.6050...DEVICES Miscellaneous Devices § 872.6050 Saliva absorber. (a) Identification. A saliva absorber is a device made of paper or...

2014-04-01

127

21 CFR 872.6050 - Saliva absorber.  

Code of Federal Regulations, 2012 CFR

... 2012-04-01 2012-04-01 false Saliva absorber. 872.6050 Section 872.6050...DEVICES Miscellaneous Devices § 872.6050 Saliva absorber. (a) Identification. A saliva absorber is a device made of paper or...

2012-04-01

128

21 CFR 872.6050 - Saliva absorber.  

Code of Federal Regulations, 2013 CFR

... 2013-04-01 2013-04-01 false Saliva absorber. 872.6050 Section 872.6050...DEVICES Miscellaneous Devices § 872.6050 Saliva absorber. (a) Identification. A saliva absorber is a device made of paper or...

2013-04-01

129

Mushroom plasmonic metamaterial infrared absorbers  

NASA Astrophysics Data System (ADS)

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.

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

2015-01-01

130

Cold fusion, Alchemist's dream  

SciTech Connect

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.

Clayton, E.D.

1989-09-01

131

Damage tolerant light absorbing material  

DOEpatents

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.

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

1993-09-07

132

Waveform-dependent absorbing metasurfaces.  

PubMed

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

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

2013-12-13

133

Waveform-dependent absorbing metasurfaces  

E-print Network

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.

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

2014-01-01

134

Damage tolerant light absorbing material  

DOEpatents

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.

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

135

Evidence for Cold Accretion onto a Massive Galaxy at High Redshift?  

E-print Network

In this letter we report on the discovery of a z=2.83 Lyman-alpha Blob (LAB) found in our wide field narrow-band survey within the Spitzer First Look Survey region. The blob is extended over at least 95kpc and has a total Lyman-alpha luminosity of 2.1 x 10^44 erg/s. It is only the sixth LAB known of this scale (> 50 kpc), and is associated with an embedded continuum source in g', R, i', K & 4.5 um bands. The LAB's optical spectrum shows clumpy structures and tantalising hints of a sharp red cut-off and shear within the Ly-alpha emission line. Studies of the LAB's surface brightness profile and of the continuum counterpart's spectral energy distribution (SED) indicate that the profuse Lyman-alpha emission is consistent with being powered by cold gas accreting onto a massive dark matter halo.

Daniel J. B. Smith; Matt J. Jarvis

2007-04-30

136

Evaluation of Shock Absorber Models  

Microsoft Academic Search

A non exhaustive overview of shock absorber models is presented. The ability of the models to match experimental data is emphasized. Two physical models are presented that are able to extract the internal valve parameters from data without hysteresis. In order to implement a model that copes with hysteresis, most models require the numerical solution to a set of nonlinear

STEFAAN DUYM; RANDY STIENS; KOENRAAD REYBROUCK

1997-01-01

137

Radar Absorbing Applications of Metamaterials  

Microsoft Academic Search

Radar absorbing materials (RAM) is used to camouflage or shield highly reflective surfaces such metallic surfaces from incident electromagnetic (EM) waves. In this paper, we explore the applications of metamaterials as conformal RAM coatings for controlling the reflection of EM waves from metal surfaces. Metamaterials are engineered materials with specially designed metallic resonant structures that are much smaller than the

Vasundara V. Varadan

2007-01-01

138

Oil and fat absorbing polymers  

NASA Technical Reports Server (NTRS)

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.

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

1977-01-01

139

Selective absorbing surfaces in practice  

Microsoft Academic Search

Selective absorbing surface treatments have become commercially viable processes for the cost-effective conversion of solar energy to thermal energy. Properties of coatings and methods of measuring the parameters are described. In this paper selective surface production technology, including electrodeposition, chemical conversion and physical vapor deposition, is reviewed. Specific examples of the development of the principal surfaces, nickel black, black chrome,

J. J. Mason

1983-01-01

140

Cold Air Damming  

NSDL National Science Digital Library

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.

COMET

2001-06-18

141

The Common Cold  

NSDL National Science Digital Library

When winter rolls around and we begin to spend more time indoors, the common cold becomes an unfortunate reality for many of us. But for something as common as the cold, misconceptions about it are remarkably common as well. The following collection of Web sites provides an in-depth look at the cold and the cold virus.The first site (1) comes from the Common Cold Care Center of Cardiff University in Wales, and offers a thorough and highly readable introduction to the common cold, including sections on conventional and alternative cold medications. Readers can brush up on their basic virology with the next Web site from HowStuffWorks to get a clear, general idea of how the cold virus infects the body (2). This site also explains why antibiotics have no effect on a virus, and includes numerous hypertext links to related HowStuffWorks Web pages. KidsHealth for Parents, a service of the Nemours Foundation, provides a straightforward guide to the symptoms of cold vs. flu, while also offering information on flu treatment options (3). The next Web site, from University of Guelph, contains an easy-to-understand comparison of bacteria and viruses (4). Readers can learn more about rhinoviruses, the family of viruses which account for about one-third of all colds, in the following Web site from the University of South Carolina's Microbiology and Immunology Online (5). The next Web site offers visitors a close-up look at human rhinovirus 14 with over a dozen 3-D images and movies from the University of Wisconsin-Madison Bock Laboratory (6). The following site describes the findings, as detailed in the Proceedings of the National Academy of Sciences, of a Purdue University research team that has analyzed on an atomic scale the structure of the cellular receptor that binds cold-causing viruses (7). And finally, find out about common cold clinical trials with ClinicalTrial.gov, a service of the National Institutes of Health (8).

Sohmer, Rachel.

2003-01-01

142

Efficient Desalination with Fractal Absorbers  

NASA Astrophysics Data System (ADS)

A class of Ramified graphs (RG) is introduced as Iterated Function Systems (IFS) to optimally design networks for efficient reverse osmosis desalination in deep seawater. Different forms of the IFS are presented, along with a corresponding contractivity factor sc, in order to identify the attractors of the systems and their fractal dimension. Using the analogy to electrostatics, the diffusion equation is solved for the desalination systems under three different boundary conditions, i) all nodes having the same pressure difference across the absorbers, ii) all nodes producing permeate at identical rates, and iii) each node having the same salt node strength. Optimal branching angles and branch length ratios are found by phase-space and discrete simulated annealing search techniques for each boundary condition, which either maximize production of permeate or minimize expenditure of energy for different fixed numbers of absorbers. Dependence of desalination recovery ratios on the geometry and fractal dimension of the RG is also explored.

Singleton, Martin; Heiss, Gregor; Hubler, Alfred

2008-03-01

143

Absorbable biologically based internal fixation.  

PubMed

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

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

2015-01-01

144

PT-symmetric laser absorber  

NASA Astrophysics Data System (ADS)

In a recent work, Y. D. Chong [Phys. Rev. Lett.0031-900710.1103/PhysRevLett.105.053901 105, 053901 (2010)] proposed the idea of a coherent perfect absorber (CPA) as the time-reversed counterpart of a laser, in which a purely incoming radiation pattern is completely absorbed by a lossy medium. The optical medium that realizes CPA is obtained by reversing the gain with absorption, and thus it generally differs from the lasing medium. Here it is shown that a laser with an optical medium that satisfies the parity-time (PT) symmetry condition ?(-r)=?*(r) for the dielectric constant behaves simultaneously as a laser oscillator (i.e., it can emit outgoing coherent waves) and as a CPA (i.e., it can fully absorb incoming coherent waves with appropriate amplitudes and phases). Such a device can thus be referred to as a PT-symmetric CPA laser. The general amplification or absorption features of the PT CPA laser below lasing threshold driven by two fields are determined.

Longhi, Stefano

2010-09-01

145

Long Range Alpha the Ternary Cold Fission of $^{252}$Cf  

E-print Network

We compute the final kinetic energies of the fragments emitted in the light charged particle accompanied cold fission of $^{252}$Cf taking into account the ground state quadrupole deformation and the finite-size effects of the fragments and integrating the equations of motion for a three-body system subjected only to Coulomb forces. The initial conditions for the trajectory calculations were derived in the frame of a deformed cluster model which includes also the effect due to the absorbative nuclear part. Although the distributions of initial kinetic energies is rather broad we show that in cold fission the initial conditions can be better determined than in the usual spontaneous fission.

Misicu, S; Cãrstoiu, F; Rizea, M; Greiner, W; Misicu, Serban

1998-01-01

146

Long Range Alpha the Ternary Cold Fission of $^{252}$Cf  

E-print Network

We compute the final kinetic energies of the fragments emitted in the light charged particle accompanied cold fission of $^{252}$Cf taking into account the ground state quadrupole deformation and the finite-size effects of the fragments and integrating the equations of motion for a three-body system subjected only to Coulomb forces. The initial conditions for the trajectory calculations were derived in the frame of a deformed cluster model which includes also the effect due to the absorbative nuclear part. Although the distributions of initial kinetic energies is rather broad we show that in cold fission the initial conditions can be better determined than in the usual spontaneous fission.

Serban Misicu; A. Sandulescu; F. Carstoiu; M. Rizea; W. Greiner

1998-08-01

147

Cold hardiness in molluscs  

NASA Astrophysics Data System (ADS)

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.

Ansart, Armelle; Vernon, Philippe

2003-05-01

148

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? ...

149

Beware the Bitter Cold  

MedlinePLUS

... not be available after 05/14/2015) By Robert Preidt Friday, February 13, 2015 Related MedlinePlus Pages ... risk for heat loss in cold temperatures," Dr. Robert Glatter, an emergency physician at Lenox Hill Hospital ...

150

Shock absorber operates over wide range  

NASA Technical Reports Server (NTRS)

Piston-type hydraulic shock absorber, with a metered damping system, operates over a wide range of kinetic energy loading rates. It is used for absorbing shock and vibration on mounted machinery and heavy earth-moving equipment.

Creasy, W. K.; Jones, J. C.

1965-01-01

151

Multiband Metamaterial Absorber at Terahertz Frequencies  

NASA Astrophysics Data System (ADS)

We propose a multi-band metamaterial absorber operating at terahertz frequencies. The design, characterization, and theoretical calculation of the high performance metamaterial absorber are reported. The multi-band metamaterial absorber consists of two metallic layers separated by a dielectric spacer. Theoretical and simulated results show that the metamaterial absorber has four distinct absorption points at frequencies 0.57 THz, 1.03 THz, 1.44 THz and 1.89 THz, with the absorption rates of 99.9%, 90.3%, 83.0%, 96.1%, respectively. Two single band metamaterial absorbers and a dual band metamaterial absorber on the top layer are designed. Some multi-band absorbers can be designed by virtue of combining some single band absorbers. The multiple-reflection theory is used to explain the absorption mechanism of our investigated structures.

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

2014-05-01

152

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

NASA Astrophysics Data System (ADS)

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 (a few hundred meters per second) compared to normal solids, thus reducing the flyer speed required to create shock waves. In first experiments aluminum foils with thicknesses between 20 micrometer and 130 micrometer were accelerated to speeds up to 2.3 km/s. In addition, the impact of the flyers on plexiglas targets was studied. Additional measurements will focus on optimizing the flyer properties (thicker flyers, higher velocities) and on characterizing the flyer in more detail (temperature of the flyer and plasma ablation from the flyer). The results of these measurements will be used to design an experiment studying the dynamics of shock waves in clumpy foams, using the 100 TW laser system Leopard for back-lighting the foam target.

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

2007-11-01

153

Spectral simulation and shock absorber identification  

Microsoft Academic Search

In vehicle dynamics shock absorbers are used for the optimization of driving comfort and driving safety. Therefore, it is necessary to identify characteristics of shock absorbers under real conditions. This paper introduces the use of hardware-in-the-loop simulations for the identification of shock absorbers involving stochastic models of the road roughness. For this purpose a dynamic hydraulic test stand is used

W. Schiehlen; B. Hu

2003-01-01

154

Design of a magnetorheological automotive shock absorber  

Microsoft Academic Search

Double adjustable shock absorbers allow for independent adjustment of the yield force and post-yield damping in the force versus velocity response. To emulate the performance of a conventional double adjustable shock absorber, a magnetorheological (MR) automotive shock absorber was designed and fabricated at the University of Maryland. Located in the piston head, an applied magnetic field between the core and

Jason E. Lindler; Glen A. Dimock; Norman M. Wereley

2000-01-01

155

Double Adjustable Shock Absorbers Using Electrorheological Fluid  

Microsoft Academic Search

Double adjustable shock absorbers allow for adjustment of their yield force and post-yield damping. To emulate the performance of a conventional double adjustable shock absorber, an electrorheological (ER) automotive shock absorber was designed and fabricated at the University of Maryland. An applied electric field between two tubular electrodes, located in the piston head, increases the force required for a given

J. E. Lindler; N. M. Wereley

1999-01-01

156

Teaching in a Cold Environment.  

ERIC Educational Resources Information Center

Instructors who teach outdoors in an environment so cold as to cause injury must satisfy program objectives while avoiding cold injury to themselves and students, help students focus on learning instead of discomfort, and alleviate some students' intense fear of the cold. Dealing with the cold successfully requires a thorough knowledge of:…

Ewert, Alan

157

Teaching in a Cold Environment.  

ERIC Educational Resources Information Center

Designed to help teachers deal with students in a cold environment, this article explains cold physiology and fundamental laws of heat; describes 14 common cold injuries and their current treatment; and lists a number of useful teaching techniques for cold environments. (SB)

Ewert, Alan

1979-01-01

158

Teaching in a Cold Environment.  

ERIC Educational Resources Information Center

The key to a successful program in a cold environment lies in dealing with the cold while still accomplishing program goals and objectives. Teachers and students must be aware of physiological and psychological reactions to the cold, cold injuries and their treatment, and techniques for staying warm. (SB)

Ewert, Alan

1979-01-01

159

Genetics Home Reference: Familial cold autoinflammatory syndrome  

MedlinePLUS

... the disorder. Where can I find information about diagnosis or management of familial cold autoinflammatory syndrome? These ... people use for familial cold autoinflammatory syndrome? cold hypersensitivity familial cold-induced autoinflammatory syndrome familial cold urticaria ...

160

Porcelain enamel neutron absorbing material  

DOEpatents

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.

Iverson, D.C.

1987-11-20

161

Graphene based salisbury screen for terahertz absorber  

NASA Astrophysics Data System (ADS)

A graphene-based, multiband absorber operating in terahertz (THz) frequency range was demonstrated. Graphene film was transferred onto the top of a flexible polymer substrate backed with a gold reflector. The graphene acts as a resistive film that partially attenuates and reflects THz waves. The destructive interference between THz waves reflected from graphene and backside reflector gives rise to perfect absorbance at multiple frequencies. To enhance the absorbance on/off ratio (AR), the conductivity of graphene was varied using a chemical doping method. The resulting p-doped, graphene-based THz absorber exhibited absorbance at maxima and AR higher than 0.95 and 25 dB, respectively.

Min Woo, Jeong; Kim, Min-Sik; Woong Kim, Hyun; Jang, Jae-Hyung

2014-02-01

162

Cold sea survival.  

NASA Technical Reports Server (NTRS)

Two prototype three-man life rafts were evaluated during the winter months in Arctic waters off Kodiak Island, Alaska, to assess potential survival problems and determine tolerance limits. Each raft incorporated thermal characteristics specifically designed for cold water. Water and air temperatures varied from 0 to +2 C and -5 to +4 C respectively. All subjects were removed upon reaching subjective tolerance. The results showed that none of the clothing assemblies was adequate to maintain a person in comfort even with dry boarding. No significant biochemical shifts in the blood or urine were found. The TUL raft was found to be superior in its thermal characteristics and afforded better subject protection. General tolerance for cold water immersion, wet and dry, and cold water raft exposures are depicted graphically, based on previously reported data.

Veghte, J. H.

1972-01-01

163

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

Microsoft Academic Search

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

Liangli Lucy Yu; Kequan Kevin Zhou; John Parry

2005-01-01

164

Monogroove cold plate  

NASA Technical Reports Server (NTRS)

The coolant fluid evaporated in a compact heat absorbing panel utilizing monogroove heat pipes in a pumped two-phase system is replenished through a liquid inlet control valve under the control of an ultrasonic liquid presence detector which is connected to the panel. The detector maintains the desired liquid quantity in the panel's liquid coolant channels, thereby dynamically responding to varying heat loads.

Edelstein, Fred (inventor); Brown, Richard F. (inventor)

1987-01-01

165

Oxalate: Effect on calcium absorbability  

SciTech Connect

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.

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

1989-10-01

166

Hydrodynamic simulations of the interaction of supernova shock waves with a clumpy environment: the case of the RX J0852.0-4622 (Vela Jr) supernova remnant  

NASA Astrophysics Data System (ADS)

Observations in all electromagnetic bands show that many supernova remnants (SNRs) have a very aspherical shape. This can be the result of asymmetries in the supernova explosion or a clumpy circumstellar medium. We study the generation of inhomogeneities and the mixing of elements arising from these two sources in multidimensional hydrodynamic simulations of the propagation of a supernova blast wave into a cloudy environment. We model a specific SNR, Vela Jr (RX J0852.0-4622). By comparing our results with recent observations, we can constrain the properties of the explosion. We find that a very energetic explosion of several 1051 erg occurring roughly about 800 years ago is consistent with the shape and emission of the SNR, as well as a supernova with an energy closer to the canonical value of 1051 erg a few thousand years ago.

Obergaulinger, M.; Iyudin, A. F.; Müller, E.; Smoot, G. F.

2014-01-01

167

Cold Sores (HSV-1)  

MedlinePLUS

... a person's lip) via the nerve endings. The area below the skin's surface, where the cold sore is going to appear, starts to tingle, itch, or burn. A red bump appears in the area about a day or so after the tingling. ...

168

Catching a Cold  

NSDL National Science Digital Library

The purpose of this assessment probe is to elicit students' ideas about infectious disease. The probe is designed to find out whether students use the germ theory to explain what causes an infectious disease like the common cold. This free selection includes the Preface, Introduction, Table of Contents, and the Index.

Joyce Tugel

2009-03-01

169

Tumor Cold Ischemia  

Cancer.gov

In a recently published manuscript in the journal of Molecular and Cellular Proteomics, researchers from the National Cancer Institutes (NCI) Clinical Proteomic Tumor Analysis Consortium (CPTAC) investigated the effect of cold ischemia on the proteome of fresh frozen tumors.

170

Galactic cold cores  

NASA Astrophysics Data System (ADS)

The project Galactic Cold Cores is studying the early stages of Galactic star formation using far-infrared and sub-millimetre observations of dust emission. The Planck satellite has located many sources of cold dust emission that are likely to be pre-stellar clumps in interstellar clouds. We have mapped a sample of Planck-detected clumps with the Herschel satellite at wavelengths 100-500 ?m. Herschel has confirmed the Planck detections of cold dust and have revealed a significant amount of sub-structure in the clumps. The cloud cores have colour temperatures in the range of 10-15 K. However, star formation is often already in progress with cold clumps coinciding with mid-infrared point sources. In less than half of the cases, the cloud morphology is clearly dominated by filamentary structures. The sources include both nearby isolated globules and more distant, massive clouds that may be off-the-plane counterparts of infrared dark clouds. The Herschel observations have been completed and the processed maps will be released to the community in 2013.

Juvela, M.

2015-03-01

171

Cold Facts about Viruses.  

ERIC Educational Resources Information Center

Provides ways for students to demonstrate their understanding of scientific concepts and skills. Describes a mini-unit around the cold in which students can relate humans to viruses. Includes activities and a modified simulation that provides questions to guide students. Discusses ways that allows students to apply prior knowledge, take ownership…

Pea, Celeste; Sterling, Donna R.

2002-01-01

172

Teaching "In Cold Blood."  

ERIC Educational Resources Information Center

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…

Berbrich, Joan D.

1967-01-01

173

A hybrid active-passive sound absorber  

NASA Astrophysics Data System (ADS)

The structure of an active-passive sound absorber is considered, and issues concerning analytic and experimental studies of the efficiency of sound absorber operation are discussed. A description is presented of both the passive part of the hybrid sound absorber and the active system incorporated in it. A test bench constructed on the basis of a low-frequency acoustic interferometer for measuring the sound absorption coefficient and the input impedance of the hybrid sound absorber under normally incident sound waves is described. An algorithm is proposed for controlling the active system of the hybrid sound absorber. The operation efficiency of the active system controlled by the proposed algorithm is analytically investigated. The results obtained from the experimental study of the hybrid active-passive sound absorber on the measuring test bench are presented.

Belov, V. D.; Migun, Yu. G.; Orlov, A. I.

2012-07-01

174

Electromagnetic scattering by pyramidal and wedge absorber  

NASA Technical Reports Server (NTRS)

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.

Dewitt, Brian T.; Burnside, Walter D.

1988-01-01

175

Magnetic field effects on microwave absorbing materials  

NASA Technical Reports Server (NTRS)

The objective of this program was to gather information to formulate a microwave absorber that can work in the presence of strong constant direct current (DC) magnetic fields. The program was conducted in four steps. The first step was to investigate the electrical and magnetic properties of magnetic and ferrite microwave absorbers in the presence of strong magnetic fields. This included both experimental measurements and a literature survey of properties that may be applicable to finding an appropriate absorbing material. The second step was to identify those material properties that will produce desirable absorptive properties in the presence of intense magnetic fields and determine the range of magnetic field in which the absorbers remain effective. The third step was to establish ferrite absorber designs that will produce low reflection and adequate absorption in the presence of intense inhomogeneous static magnetic fields. The fourth and final step was to prepare and test samples of such magnetic microwave absorbers if such designs seem practical.

Goldberg, Ira; Hollingsworth, Charles S.; Mckinney, Ted M.

1991-01-01

176

Clumpy photon-dominated regions in Carina. I. [CI] and mid-J CO lines in two 4'x4' fields  

E-print Network

The Carina region is an excellent astrophysical laboratory for studying the feedback mechanisms of newly born, very massive stars within their natal giant molecular clouds (GMCs) at only 2.35 kpc distance. We use a clumpy PDR model to analyse the observed intensities of atomic carbon and CO and to derive the excitation conditions of the gas. The NANTEN2-4m submillimeter telescope was used to map the [CI] 3P1-3P0, 3P2-3P1 and CO 4-3, 7-6 lines in two 4'x4' regions of Carina where molecular material interfaces with radiation from the massive star clusters. One region is the northern molecular cloud near the compact OB cluster Tr14, and the second region is in the molecular cloud south of etaCar and Tr16. These data were combined with 13CO SEST spectra, HIRES/IRAS 60um and 100um maps of the FIR continuum, and maps of 8um IRAC/Spitzer and MSX emission. We used the HIRES far-infrared dust data to create a map of the FUV field heating the gas. The northern region shows an FUV field of a few 1000 in Draine units while the field of the southern region is about a factor 10 weaker. We constructed models consisting of an ensemble of small spherically symmetric PDR clumps within the 38" beam (0.43pc), which follow canonical power-law mass and mass-size distributions. We find that an average local clump density of 2x10**5 cm-3 is needed to reproduce the observed line emission at two selected interface positions. Stationary, clumpy PDR models reproduce the observed cooling lines of atomic carbon and CO at two positions in the Carina Nebula.

C. Kramer; M. Cubick; M. Roellig; K. Sun; Y. Yonekura; M. Aravena; F. Bensch; A. Benz; F. Bertoldi; L. Bronfman; M. Fujishita; Y. Fukui; U. U. Graf; M. Hitschfeld; N. Honingh; S. Ito; H. Jakob; K. Jacobs; U. Klein; B. -C. Koo; J. May; M. Miller; Y. Miyamoto; N. Mizuno; T. Onishi; Y. -S. Park; J. L. Pineda; D. Rabanus; H. Sasago; R. Schieder; R. Simon; J. Stutzki; N. Volgenau; H. Yamamoto

2007-11-08

177

Boron-copper neutron absorbing material and method of preparation  

DOEpatents

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.

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

1991-01-01

178

Absorbent product and articles made therefrom  

NASA Technical Reports Server (NTRS)

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.

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

1982-01-01

179

TPX/TFTR Neutral Beam energy absorbers  

SciTech Connect

The present beam energy absorbing surfaces on the TFTR Neutral Beams such as Ion Dumps, Calorimeters, beam defining apertures, and scrapers, are simple water cooled copper plates which wee designed to absorb (via their thermal inertia) the incident beam power for two seconds with a five minute coal down interval between pulses. These components are not capable of absorbing the anticipated beam power loading for 1000 second TPX pulses and will have to be replaced with an actively cooled design. While several actively cooled energy absorbing designs were considered,, the hypervapotron elements currently being used on the JET beamlines were chosen due to their lower cooling water demands and reliable performance on JET.

Dahlgren, F.; Wright, K.; Kamperschroer, J.; Grisham, L.; Lontai, L.; Peters, C.; VonHalle, A.

1993-11-01

180

Photoacoustic cavitation in spherical and cylindrical absorbers  

NASA Astrophysics Data System (ADS)

Photomechanical damage in absorbing regions or particles surrounded by a non-absorbing medium is investigated experimentally and theoretically. The damage mechanism is based on the generation of thermoelastic pressure by absorption of pulsed laser radiation under conditions of stress confinement. Principles of photoacoustic sound generation predict that the acoustic wave generated in a finite-size absorbing region must contain both compressive and tensile stresses. Time-resolved imaging experiments were performed to examine whether the tensile stress causes cavitation in absorbers of spherical or cylindrical shape. The samples were absorbing water droplets and gelatin cylinders suspended in oil. They were irradiated with 6-ns-long pulses from an optical parametric oscillator. Photoacoustic cavitation was observed near the center of the absorbers, even if the estimated temperature caused by absorption of the laser pulse did not exceed the boiling point. The experimental findings are supported by theoretical simulations that reveal strong tensile stress in the interior of the absorbers, near the center of symmetry. Tensile stress amplitudes depend on the shape of the absorber, the laser pulse duration, and the ratio of absorber size to optical absorption length. The photoacoustic damage mechanism has implications for the interaction of ns and sub-nslaser pulses with pigmented structures in biological tissue.

Paltauf, G.; Schmidt-Kloiber, H.

181

A planar polarization-insensitive metamaterial absorber  

NASA Astrophysics Data System (ADS)

The model of the polarization-insensitive metamaterial (MM) absorber composed of split cross-ring resonator (SCRR), cave-cross resonator (CCR) and dielectric substrate was proposed at microwave frequencies. Based on perfect impedance-matched ( z˜(?)=1) to the free space, the single unit cell could achieve near-unity absorbance by properly assembling the sandwich structure. We have simulated and measured the reflectivity and transmission properties of a planar MM absorber with the thickness of 0.6 mm. The absorptivity of a single layer MM absorber achieve greater than 96% around 10.07 GHz in experiments and 98% in simulations for incident electromagnetic (EM) wave with different polarizations.

Cheng, Yongzhi; Yang, Helin; Cheng, Zhengze; Xiao, Boxun

2011-02-01

182

Thermoregulatory modeling for cold stress.  

PubMed

Modeling for cold stress has generated a rich history of innovation, has exerted a catalytic influence on cold physiology research, and continues to impact human activity in cold environments. This overview begins with a brief summation of cold thermoregulatory model development followed by key principles that will continue to guide current and future model development. Different representations of the human body are discussed relative to the level of detail and prediction accuracy required. In addition to predictions of shivering and vasomotor responses to cold exposure, algorithms are presented for thermoregulatory mechanisms. Various avenues of heat exchange between the human body and a cold environment are reviewed. Applications of cold thermoregulatory modeling range from investigative interpretation of physiological observations to forecasting skin freezing times and hypothermia survival times. While these advances have been remarkable, the future of cold stress modeling is still faced with significant challenges that are summarized at the end of this overview. PMID:24944030

Xu, Xiaojiang; Tikuisis, Peter

2014-07-01

183

Hot and Cold  

NSDL National Science Digital Library

In this chemistry challenge, learners discover that many chemical reactions involve heat loss or gain. With this understanding, they try to find a combination of chemicals that could be used to make an instant cold pack. They are given baking soda, ammonium nitrate, calcium chloride, and potassium chloride, along with vinegar and water (3% hydrogen peroxide and yeast can also be used). Learners combine chemicals into calorimeters, then use thermometers to measure how the temperature changes. Calorimeters can be made by pushing a heated test tube into home insulation foam (instructions in PDF) or can be purchased (one source is Flinn Scientific). The water and ammonium nitrate, and vinegar and baking soda, are candidates for making a cold pack.

Sciencenter

2014-08-27

184

WISPy cold dark matter  

SciTech Connect

Very weakly interacting slim particles (WISPs), such as axion-like particles (ALPs) or hidden photons (HPs), may be non-thermally produced via the misalignment mechanism in the early universe and survive as a cold dark matter population until today. We find that, both for ALPs and HPs whose dominant interactions with the standard model arise from couplings to photons, a huge region in the parameter spaces spanned by photon coupling and ALP or HP mass can give rise to the observed cold dark matter. Remarkably, a large region of this parameter space coincides with that predicted in well motivated models of fundamental physics. A wide range of experimental searches — exploiting haloscopes (direct dark matter searches exploiting microwave cavities), helioscopes (searches for solar ALPs or HPs), or light-shining-through-a-wall techniques — can probe large parts of this parameter space in the foreseeable future.

Arias, Paola; Goodsell, Mark; Ringwald, Andreas [Deutsches Elektronen-Synchrotron, Notkestraße 85, D-22607 Hamburg (Germany); Cadamuro, Davide; Redondo, Javier [Max-Planck-Institut für Physik, Föhringer Ring 6, D-80805 München (Germany); Jaeckel, Joerg, E-mail: paola.arias@desy.de, E-mail: cadamuro@mppmu.mpg.de, E-mail: mark.goodsell@cern.ch, E-mail: joerg.jaeckel@durham.ac.uk, E-mail: redondo@mppmu.mpg.de, E-mail: andreas.ringwald@desy.de [Institute for Particle Physics Phenomenology, Durham University, Durham DH1 3LE (United Kingdom)

2012-06-01

185

Radial cold trap  

DOEpatents

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.

Grundy, Brian R. (Greensburg, PA)

1981-01-01

186

Radial cold trap  

DOEpatents

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.

Grundy, B.R.

1981-09-29

187

Cold Metastable NH molecules  

NASA Astrophysics Data System (ADS)

We report progress towards producing samples of cold trapped NH molecules using a stark decelerator. The NH molecule has a metastable state (a1Delta) approximately 1.5 eV above the ground state and a lifetime of several seconds. We create of a beam of cold NH molecules almost entirely in the a1 delta state by supersonic expansion and in situ photolysis of HNCO. We determine the rotational and translation temperatures of the beam using 2+1 resonance enhanced multi-photon ionization spectroscopy. The NH molecules are then slowed in a stark decelerator and trapped using static electric fields. Once the molecules are trapped, we will overlap a magnetic trap of ultracold rubidium atoms to study near-resonant quenching of metastable NH.

Fabrikant, Maya; Briles, Travis; Fitch, Noah; Lewandowski, Heather

2011-06-01

188

Highly efficient special sound absorbing solutions  

NASA Technical Reports Server (NTRS)

Highly efficient special sound absorbing structures with the following criteria are considered: (1) A distribution surface of the sound absorbing material greater than that of the building element on which the structure is placed; (2) The highest possible absorption coefficient in the widest possible frequency band; and (3) adaptability to different construction and aesthetic conditions.

Ionescu, M.; Petre-Lazar, S.

1974-01-01

189

Electrorheological Squeeze-Flow Shock Absorber  

Microsoft Academic Search

We developed a squeeze-flow shock absorber and tested it under impact conditions typical of heavy-duty recoil mechanisms. In contrast to common shear-flow shock absorbers, here the volume of fluid driven by the piston does not flow through the regions of high electric field. Experiments on three commercially available \\

Boris Khusid; Andreas Acrivos; Yakov Khodorkovsky; Michael Beltran

1999-01-01

190

Proton Absorber Feasibility Study Chris Rogers,  

E-print Network

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

McDonald, Kirk

191

Catalytically deposited carbon solar selective absorber  

Microsoft Academic Search

This selective absorber consists of a number of thin layers on a supporting substrate, including a carbonaceous absorbing layer, a catalyst layer, and a metallic infrared reflecting layer. The catalyst layer serves to catalyze the pyrolysis of a carbon containing gaseous compound to form the carbonaceous layer. Under proper conditions, the layer is black, strongly bonded to the surface, and

J. D. Garrison

1982-01-01

192

Pyro-adaptive impact energy absorber  

Microsoft Academic Search

The paper contains a proposal of energy dissipation density controlling in lightweight thinwalled structures by reducing their crushing stiffness during an impact process. For small scale laboratory experiments, low-energy-dissipation absorber was developed. Prismatic absorber made of thin lead sheets can dissipate the impact energy at two energy density levels. Moving the concept to the real steel or aluminum structures can

Marian Ostrowski; Paulius Griskevicius; Jan Holnicki-Szulc

193

Black nickel selective absorber, optimization of parameters  

Microsoft Academic Search

Electroplated black nickel selective absorber is one of the most commercially used element of solar energy systems. Electrodeposition parameters such as time of deposition, pH, current density, electrolyte temperature should be optimized to produce the most efficient selective absorber. The topology of the substrate material is very effective on selectivity and it should also be optimized. In this study, by

B. Akinoglu; V. Cercioglu; A. Ecevit

1983-01-01

194

An application of metamaterials: Perfect absorbers  

NASA Astrophysics Data System (ADS)

We studied structures that describe the perfect-absorber effect by using different mechanisms. Firstly, we investigated the dependences of the reflectance and the absorbance of a metamaterial, as structure proposed by Landy et al. [Phys. Rev. Lett. 100, 207402 (2008)] on gap `g' of the structure at GHz frequencies. The value of the gap was obtained, which gives the maximum absorbance and the minimum reflectance. In addition, the change of geometry of the electric ring resonance as an I-shape made the reflectance disappear at the resonance frequency. A narrow-band peak of the perfect-absorber effect, which was enhanced to be greater than 99.5% at 13.5 GHz, was observed by using a multilayer model for the simplified absorber structure. Secondly, we investigated an absorber structure that includes two metal layers, periodic cut-wire bars at the front and a copper plane at the back, separated by a dielectric layer. The results showed that the absorbance and the resonance frequency of this structure strongly depended on the thickness and the length of the cut-wire bar, respectively. Base on these, we successfully designed a broad-band absorber structure by arranging cut-wire bars with different lengths appropriately in a "meta-atom".

Lee, Y. P.; Tuong, P. V.; Zheng, H. Y.; Rhee, J. Y.; Jang, W. H.

2012-04-01

195

Cold nuclear fusion  

Microsoft Academic Search

The possibility that negative muons could catalyze nuclear fusion was suggested on theoretical grounds by F.C. Frank and A.D. Sakharov in the late 1940s; the first experimental observations of the process followed serendipitously a decade later, in experiments at Berkeley by L.W. Alvarez. The fastest mechanism for muon-catalyzed, or 'cold' fusion, was suggested by Vesman (1967); it depends on a

Johann Rafelski; Steven E. Jones

1987-01-01

196

Shock energy absorber including collapsible energy absorbing element and break up of tensile connection  

SciTech Connect

This patent describes a shock absorber adapted to include a detonating cord for receiving and absorbing mechanical energy resultant from a shock. It comprises an outer housing; an inner housing; connection means for connecting the inner housing to the outer housing; break up means responsive to the detonation wave propagating in the detonating cord; collapsible energy absorbing element means responsive to the mechanical energy.

Miszewski, A.K.L.; Huber, K.B.

1992-07-21

197

An Absorbing Boundary Condition Based on Anechoic Absorber For EM Scattering Computation  

Microsoft Academic Search

A novel absorbing boundary condition (ABC), to be used with finite difference and finite element electromagnetic radiation and scattering problems is described. It is based on anechoic chamber absorber foam geometry, with specified complex permittivity and permeability. The advantage of this absorbing boundary is that it prevents reflections from much wider incident angles than currently used lattice termination conditions. Since

C. M. Rappaport; L. J. Bahrmasel

1992-01-01

198

Cold Stowage Flight Systems  

NASA Technical Reports Server (NTRS)

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.

Campana, Sharon E.; Melendez, David T.

2011-01-01

199

Cold Stowage Flight Systems  

NASA Technical Reports Server (NTRS)

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.

Campana, Sharon

2010-01-01

200

Porous metal absorbers for underwater sound.  

PubMed

Rubber has traditionally been used for underwater sound absorption. Porous metal is a relatively lightweight material and also has higher strength than rubber. However, exactly how porous metals can be used as effective underwater sound absorbers remains unclear. This paper shows how to use porous metal absorbers so that they work well under water, even under fairly constrained conditions. A method of nondimensional analysis is proposed that allows identification of vital characteristics. This means that such characteristics can be varied and the absorbers themselves filled with different types of viscous fluids. Such analysis suggests that the sound absorption coefficient of porous metals does not always increase when there are either increases in porosity or decreases in average pore size. The same method of analysis can show how, by choice of the right characteristics to choose a suitable viscous fluid, a porous metal absorber can be built that takes up little space but still effectively absorbs underwater sounds at low frequencies. PMID:18189554

Wang, Xiaolin

2007-11-01

201

Solar sustained plasma/absorber conceptual design  

NASA Technical Reports Server (NTRS)

A space power system concept was evaluated which uses concentrated solar energy to heat a working fluid to temperatures as high as 4000 K. The high temperature working fluid could be used for efficient electric power production in advanced thermal or magnetohydrodynamic conversion cycles. Energy absorber configurations utilizing particles or cesium vapor absorber material were investigaed. Results of detailed radiant heat transfer calculations indicated approximately 86 percent of the incident solar energy could be absorbed within a 12-cm-dia flowing stream of gas borne carbon particles. Calculated total energy absorption in the cesium vapor seeded absorber configuration ranged from 34 percent to 64 percent of the incident solar energy. Solar flux concentration ratios of between approximately 3000 and 10,000 will be required to sustain absorber temperatures in the range from 3000 K to 4000 K.

Rodgers, R. J.; Krascella, N. L.; Kendall, J. S.

1979-01-01

202

The origin of cold gas in giant elliptical galaxies and its role in fuelling radio-mode AGN feedback  

NASA Astrophysics Data System (ADS)

The nature and origin of the cold interstellar medium (ISM) in early-type galaxies are still a matter of debate, and understanding the role of this component in galaxy evolution and in fuelling the central supermassive black holes requires more observational constraints. Here, we present a multiwavelength study of the ISM in eight nearby, X-ray and optically bright, giant elliptical galaxies, all central dominant members of relatively low-mass groups. Using far-infrared spectral imaging with the Herschel Photodetector Array Camera & Spectrometer, we map the emission of cold gas in the cooling lines of [C II]?157 ?m, [O I] ?63 ?m and [O Ib] ?145 ?m. Additionally, we present H?+[N II] imaging of warm ionized gas with the Southern Astrophysical Research (SOAR) telescope, and a study of the thermodynamic structure of the hot X-ray emitting plasma with Chandra. All systems with extended H? emission in our sample (6/8 galaxies) display significant [C II] line emission indicating the presence of reservoirs of cold gas. This emission is cospatial with the optical H?+[N II] emitting nebulae and the lowest entropy soft X-ray emitting plasma. The entropy profiles of the hot galactic atmospheres show a clear dichotomy, with the systems displaying extended emission-line nebulae having lower entropies beyond r ? 1 kpc than the cold-gas-poor systems. We show that while the hot atmospheres of the cold-gas-poor galaxies are thermally stable outside of their innermost cores, the atmospheres of the cold-gas-rich systems are prone to cooling instabilities. This provides considerable weight to the argument that cold gas in giant ellipticals is produced chiefly by cooling from the hot phase. We show that cooling instabilities may develop more easily in rotating systems and discuss an alternative condition for thermal instability for this case. The hot atmospheres of cold-gas-rich galaxies display disturbed morphologies indicating that the accretion of clumpy multiphase gas in these systems may result in variable power output of the AGN jets, potentially triggering sporadic, larger outbursts. In the two cold-gas-poor, X-ray morphologically relaxed galaxies of our sample, NGC 1399 and NGC 4472, powerful AGN outbursts may have destroyed or removed most of the cold gas from the cores, allowing the jets to propagate and deposit most of their energy further out, increasing the entropy of the hot galactic atmospheres and leaving their cores relatively undisturbed.

Werner, N.; Oonk, J. B. R.; Sun, M.; Nulsen, P. E. J.; Allen, S. W.; Canning, R. E. A.; Simionescu, A.; Hoffer, A.; Connor, T.; Donahue, M.; Edge, A. C.; Fabian, A. C.; von der Linden, A.; Reynolds, C. S.; Ruszkowski, M.

2014-04-01

203

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

SciTech Connect

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.

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

204

Thin film absorber for a solar collector  

DOEpatents

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.

Wilhelm, William G. (Cutchogue, NY)

1985-01-01

205

Extended Ly? Emission from a Damped Ly? Absorber at z = 3.115  

NASA Astrophysics Data System (ADS)

We searched for star formation activity associated with high-z damped Ly? systems (DLAs) with the Subaru telescope. We used a set of narrow-band (NB) filters whose central wavelengths correspond to the redshifted Ly? emission lines of targeted DLA absorbers at 3 < z < 4.5. We detected one apparent NB-excess object located 3.80 arcsec ({\\sim }28\\ h_{70}^{-1} kpc) away from the quasar SDSS J031036.84+005521.7. Follow-up spectroscopy revealed an asymmetric Ly? emission at z em = 3.115 ± 0.003, which perfectly matches the sub-DLA trough at z abs = 3.1150 with logN(H I)/cm-2 = 20.05. The Ly? luminosity is estimated to be L Ly? = 1.07 × 1042 erg s-1, which corresponds to a star formation rate of 0.97 M ? yr-1. Interestingly, the detected Ly? emission is spatially extended with a sharp peak. The large extent of the Ly? emission is remarkably one-sided toward the quasar line-of-sight and is redshifted. The observed spatially asymmetric surface brightness profile can be qualitatively explained by a model of a DLA host galaxy, assuming a galactic outflow and a clumpy distribution of H I clouds in the circumgalactic medium. This large Ly? extension, which is similar to those found in Rauch et al., could be the result of complicated anisotropic radiative transfer through the surrounding neutral gas embedded in the DLA. Based on data collected at the Subaru telescope, which is operated by the National Astronomical Observatory of Japan.

Kashikawa, Nobunari; Misawa, Toru; Minowa, Yosuke; Okoshi, Katsuya; Hattori, Takashi; Toshikawa, Jun; Ishikawa, Shogo; Onoue, Masafusa

2014-01-01

206

Warm Absorbers in X-rays (WAX), a comprehensive high resolution grating spectral study of a sample of Seyfert galaxies  

NASA Astrophysics Data System (ADS)

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. We could put a strict lower limit on the detection fraction of 50%. We find a gap in the distribution of the ionisation parameter in the range 0.5absorber flow is probably constituted by a clumpy distribution of discrete clouds. 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 lines. Therefore the detected broad Fe K lines are bonafide and not artefacts of ionised absorption in the soft X-rays. The WA parameters show no correlation among themselves, except for one case. The shallow slope of the log? versus logv_{out} linear regression (0.12± 0.03) is inconsistent with the scaling laws predicted by radiation or magneto-hydrodynamic-driven winds. Our results suggest also that WA and Ultra Fast Outflows (UFOs) do not represent extreme manifestation of the same astrophysical system.

Laha, S.; Guainazzi, M.; Dewangan, G.; Chakravorty, S.; Kembhavi, A.

2014-07-01

207

A thermally tunable terahertz metamaterial absorber  

NASA Astrophysics Data System (ADS)

A thermally tunable terahertz metamaterial absorber (MA) with InSb embedded in a metal-dielectric-metal structure is proposed. The transmission and tuning properties of the proposed metamaterial absorber are analyzed for the temperature ranging from 160 K to 350 K. The simulated results show that the maximum absorption of the absorber is nearly 99.8% at a full-width at half-maximum (FWHM) of 38 GHz, and the absorption frequency can be dynamically tuned from 0.82 THz to 1.02 THz.

Zheng, Wei; Li, Wei; Chang, Sheng-jiang

2015-01-01

208

Microwave diode switchable metamaterial reflector/absorber  

NASA Astrophysics Data System (ADS)

We embed diodes as active circuit elements within a metamaterial to implement a switchable metamaterial reflector/absorber at microwave frequencies. Diodes are placed in series with the unit cells of the metamaterial array. This results in just a pair of control lines to actively tune all the diodes in a metamaterial. Diodes can be tuned on and off to switch the function of the metamaterial between a perfect absorber and a reflector. The design, simulation, and experimental results of a switchable reflector/absorber in 2-6 GHz range are presented.

Xu, Wangren; Sonkusale, Sameer

2013-07-01

209

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

SciTech Connect

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.

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

210

Cold War in Southern Africa  

Microsoft Academic Search

Review Article: Cold War in Southern Africa

  • Gary Baines, Peter Vale (eds.) (2008), Beyond the Border War: New Perspectives on Southern Africa’s Late-Cold War Conflicts, Pretoria: Unisa Press, ISBN 978 1 86888 456 8, xix + 342 pp. <\\/li>
  • Sue Onslow (ed.) (2009), Cold War in Southern Africa: White Power, Black Liberation, Abingdon: Routledge, ISBN 978 0 415 47420 7, 253

    Matthew Graham

    2010-01-01

211

Energy absorber uses expanded coiled tube  

NASA Technical Reports Server (NTRS)

Mechanical shock mitigating device, based on working material to its failure point, absorbs mechanical energy by bending or twisting tubing. It functions under axial or tangential loading, has no rebound, is area independent, and is easy and inexpensive to build.

Johnson, E. F.

1972-01-01

212

Durability of Polymeric Glazing and Absorber Materials  

SciTech Connect

The Solar Heating and Lighting Program has set the goal of reducing the cost of solar water heating systems by at least 50%. An attractive approach to such large cost reduction is to replace glass and metal parts with less-expensive, lighter-weight, more-integrated polymeric components. The key challenge with polymers is to maintain performance and assure requisite durability for extended lifetimes. The objective of this task is to quantify lifetimes through measurement of the optical and mechanical stability of candidate polymeric glazing and absorber materials. Polycarbonate sheet glazings, as proposed by two industry partners, have been tested for resistance to UV radiation with three complementary methods. Incorporation of a specific 2-mil thick UV-absorbing screening layer results in glazing lifetimes of at least 15 years; improved screens promise even longer lifetimes. Proposed absorber materials were tested for creep and embrittlement under high temperature, and appear adequate for planned ICS absorbers.

Jorgensen, G.; Terwilliger, K.; Bingham, C.; Milbourne, M.

2005-01-01

213

Efficient waveform recall in absorbing media  

Microsoft Academic Search

Summary form only given. We have shown that efficient recall of temporally structured optical pulses in absorbing media can be obtained via the photon echo process if the absorption length and pulse area of brief pulses are appropriately chosen

C. S. Cornish; M. Azadeh; W. R. Babbitt; L. Tsang

1998-01-01

214

Neutron absorbing coating for nuclear criticality control  

DOEpatents

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.

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

215

Unity absorbance layers - optimal design criteria  

E-print Network

We present the necessary and sufficient conditions for the unity absorbance of thin planar layers. With a simple structure comprising a double-layer grid, it is shown that zero transmission and reflection is feasible only if the second sheet is a perfectly conducting wall. The operational frequencies can be varied by tuning the grid impedance. Explicit conditions are given at the large wavelength limit; these underline the fundamental of ultra-thin perfect antennae and absorbers.

Chalapat, K; Du, Z; Tervo, J; Nefedov, I; Tretyakov, S

2011-01-01

216

A planar polarization-insensitive metamaterial absorber  

Microsoft Academic Search

The model of the polarization-insensitive metamaterial (MM) absorber composed of split cross-ring resonator (SCRR), cave-cross resonator (CCR) and dielectric substrate was proposed at microwave frequencies. Based on perfect impedance-matched (z˜(?)=1) to the free space, the single unit cell could achieve near-unity absorbance by properly assembling the sandwich structure. We have simulated and measured the reflectivity and transmission properties of a

Yongzhi Cheng; Helin Yang; Zhengze Cheng; Boxun Xiao

2011-01-01

217

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

Code of Federal Regulations, 2011 CFR

...2011-04-01 false Absorbable implant (scleral buckling method...DEVICES OPHTHALMIC DEVICES Prosthetic Devices § 886.3300 Absorbable implant (scleral buckling method...Identification. An absorbable implant (scleral buckling...

2011-04-01

218

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

Code of Federal Regulations, 2012 CFR

...2012-04-01 false Absorbable implant (scleral buckling method...DEVICES OPHTHALMIC DEVICES Prosthetic Devices § 886.3300 Absorbable implant (scleral buckling method...Identification. An absorbable implant (scleral buckling...

2012-04-01

219

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

Code of Federal Regulations, 2013 CFR

...2013-04-01 false Absorbable implant (scleral buckling method...DEVICES OPHTHALMIC DEVICES Prosthetic Devices § 886.3300 Absorbable implant (scleral buckling method...Identification. An absorbable implant (scleral buckling...

2013-04-01

220

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

Code of Federal Regulations, 2014 CFR

...2014-04-01 false Absorbable implant (scleral buckling method...DEVICES OPHTHALMIC DEVICES Prosthetic Devices § 886.3300 Absorbable implant (scleral buckling method...Identification. An absorbable implant (scleral buckling...

2014-04-01

221

21 CFR 880.5300 - Medical absorbent fiber.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 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...

2010-04-01

222

21 CFR 868.5310 - Carbon dioxide absorber.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 2012-04-01 false Carbon dioxide absorber. 868.5310 Section...DEVICES Therapeutic Devices § 868.5310 Carbon dioxide absorber. (a) Identification. A carbon dioxide absorber is a device that is...

2012-04-01

223

21 CFR 868.5310 - Carbon dioxide absorber.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Carbon dioxide absorber. 868.5310 Section...DEVICES Therapeutic Devices § 868.5310 Carbon dioxide absorber. (a) Identification. A carbon dioxide absorber is a device that is...

2010-04-01

224

21 CFR 868.5300 - Carbon dioxide absorbent.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Carbon dioxide absorbent. 868.5300 Section...DEVICES Therapeutic Devices § 868.5300 Carbon dioxide absorbent. (a) Identification. A carbon dioxide absorbent is a device...

2010-04-01

225

21 CFR 868.5300 - Carbon dioxide absorbent.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 2011-04-01 false Carbon dioxide absorbent. 868.5300 Section...DEVICES Therapeutic Devices § 868.5300 Carbon dioxide absorbent. (a) Identification. A carbon dioxide absorbent is a device...

2011-04-01

226

21 CFR 868.5310 - Carbon dioxide absorber.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 2011-04-01 false Carbon dioxide absorber. 868.5310 Section...DEVICES Therapeutic Devices § 868.5310 Carbon dioxide absorber. (a) Identification. A carbon dioxide absorber is a device that is...

2011-04-01

227

Perfect terahertz absorber using fishnet based metafilm  

SciTech Connect

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.

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

228

Is it a Cold or the Flu? Symptoms Cold Flu  

E-print Network

Is it a Cold or the Flu? Symptoms Cold Flu Fever Rare Usual; high (100°F to 102°F, occasionally higher, especially in young children); lasts 3 to 4 days Headache Rare Common General Aches, Pains Slight Usual; at the beginning of the illness Stuffy Nose Common Sometimes Sneezing Usual Sometimes Sore Throat

Weston, Ken

229

Is It A Cold Or The Flu? Symptoms Cold Flu  

E-print Network

Is It A Cold Or The Flu? Symptoms Cold Flu Fever Rare Usual, high (100-102°) Headache be severe 5 STEPS TO TAKE IF YOU GET THE FLU: 1. Stay at home and rest. CDC recommends that you stay home a medical condition that puts you at higher risk of flu complications (like asthma...), call your doctor

O'Toole, Alice J.

230

Is It a Cold or the Flu? Symptoms Cold Flu  

E-print Network

Is It a Cold or the Flu? Symptoms Cold Flu Fever Rare Usual; high (100°F to 102°F, occasionally higher, especially in young children); lasts 3 to 4 days Headache Rare Common General Aches, Pains Slight Usual; at the beginning of the illness Stuffy Nose Common Sometimes Sneezing Usual Sometimes Sore Throat

Bandettini, Peter A.

231

A strained silicon cold electron bolometer using Schottky contacts  

SciTech Connect

We describe optical characterisation of a strained silicon cold electron bolometer (CEB), operating on a 350 mK stage, designed for absorption of millimetre-wave radiation. The silicon cold electron bolometer utilises Schottky contacts between a superconductor and an n{sup ++} doped silicon island to detect changes in the temperature of the charge carriers in the silicon, due to variations in absorbed radiation. By using strained silicon as the absorber, we decrease the electron-phonon coupling in the device and increase the responsivity to incoming power. The strained silicon absorber is coupled to a planar aluminium twin-slot antenna designed to couple to 160?GHz and that serves as the superconducting contacts. From the measured optical responsivity and spectral response, we calculate a maximum optical efficiency of 50% for radiation coupled into the device by the planar antenna and an overall noise equivalent power, referred to absorbed optical power, of 1.1×10{sup ?16}?W?Hz{sup ?1/2} when the detector is observing a 300?K source through a 4?K throughput limiting aperture. Even though this optical system is not optimized, we measure a system noise equivalent temperature difference of 6?mK?Hz{sup ?1/2}. We measure the noise of the device using a cross-correlation of time stream data, measured simultaneously with two junction field-effect transistor amplifiers, with a base correlated noise level of 300?pV?Hz{sup ?1/2} and find that the total noise is consistent with a combination of photon noise, current shot noise, and electron-phonon thermal noise.

Brien, T. L. R., E-mail: tom.brien@astro.cf.ac.uk; Ade, P. A. R.; Barry, P. S.; Dunscombe, C.; Morozov, D. V.; Sudiwala, R. V. [School of Physics and Astronomy, Cardiff University, Queen's Buildings, The Parade, Cardiff CF24 3AA (United Kingdom); Leadley, D. R.; Myronov, M.; Parker, E. H. C.; Prest, M. J.; Whall, T. E. [Department of Physics, University of Warwick, Coventry CV4 7AL (United Kingdom); Prunnila, M. [VTT Technical Research Centre of Finland, P.O. Box 1000, FI-02044 VTT Espoo (Finland); Mauskopf, P. D. [School of Physics and Astronomy, Cardiff University, Queen's Buildings, The Parade, Cardiff CF24 3AA (United Kingdom); Department of Physics and School of Earth and Space Exploration, Arizona State University, 650 E. Tyler Mall, Tempe, Arizona 85287 (United States)

2014-07-28

232

Method of absorbance correction in a spectroscopic heating value sensor  

DOEpatents

A method and apparatus for absorbance correction in a spectroscopic heating value sensor in which a reference light intensity measurement is made on a non-absorbing reference fluid, a light intensity measurement is made on a sample fluid, and a measured light absorbance of the sample fluid is determined. A corrective light intensity measurement at a non-absorbing wavelength of the sample fluid is made on the sample fluid from which an absorbance correction factor is determined. The absorbance correction factor is then applied to the measured light absorbance of the sample fluid to arrive at a true or accurate absorbance for the sample fluid.

Saveliev, Alexei; Jangale, Vilas Vyankatrao; Zelepouga, Sergeui; Pratapas, John

2013-09-17

233

Cold isopressing method  

DOEpatents

A cold isopressing method in which two or more layers of material are formed within an isopressing mold. One of the layers consists of a tape-cast film. The layers are isopressed within the isopressing mold, thereby to laminate the layers and to compact the tape-cast film. The isopressing mold can be of cylindrical configuration with the layers being coaxial cylindrical layers. The materials used in forming the layers can contain green ceramic materials and the resultant structure can be fired and sintered as necessary and in accordance with known methods to produce a finished composite, ceramic structure. Further, such green ceramic materials can be of the type that are capable of conducting hydrogen or oxygen ions at high temperature with the object of utilizing the finished composite ceramic structure as a ceramic membrane element.

Chen, Jack C. (Getzville, NY); Stawisuck, Valerie M. (North Tonawanda, NY); Prasad, Ravi (East Amherst, NY)

2003-01-01

234

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.

235

COLD STORAGE DESIGN REFRIGERATION EQUIPMENT  

E-print Network

COLD STORAGE DESIGN AND REFRIGERATION EQUIPMENT REFRIGERATION OF FISH - PART 1 \\ "..\\- ,,, T I Fishery Leaflet 427 Washington 25, D. C. June 1956 REFRIGERATION OF FISH - PART em; COlD STORAGE DESIGN AND REFRIGERATION EQUIPMENT By Charles Butler (Section 1), Joseph W. Slavin (Sections 1, 2, and 3), Max Patashnik

236

The status of cold fusion  

Microsoft Academic Search

This report attempts to update the status of the phenomenon of cold fusion. The new field is continuing to grow as a variety of nuclear reactions are discovered to occur in a variety of chemical environments at modest temperatures. However, it must be cautioned that most scientists consider cold fusion as something akin to UFO's, ESP, and numerology.

E. Storms

1993-01-01

237

The status of cold fusion  

NASA Astrophysics Data System (ADS)

This report attempts to update the status of the phenomenon of cold fusion. The new field is continuing to grow as a variety of nuclear reactions are discovered to occur in a variety of chemical environments at modest temperatures. However, it must be cautioned that most scientists consider cold fusion as something akin to UFO's, ESP, and numerology.

Storms, E.

238

On the definition of absorbed dose  

NASA Astrophysics Data System (ADS)

Purpose: The quantity absorbed dose is used extensively in all areas concerning the interaction of ionizing radiation with biological organisms, as well as with matter in general. The most recent and authoritative definition of absorbed dose is given by the International Commission on Radiation Units and Measurements (ICRU) in ICRU Report 85. However, that definition is incomplete. The purpose of the present work is to give a rigorous definition of absorbed dose. Methods: Absorbed dose is defined in terms of the random variable specific energy imparted. A random variable is a mathematical function, and it cannot be defined without specifying its domain of definition which is a probability space. This is not done in report 85 by the ICRU, mentioned above. Results: In the present work a definition of a suitable probability space is given, so that a rigorous definition of absorbed dose is possible. This necessarily includes the specification of the experiment which the probability space describes. In this case this is an irradiation, which is specified by the initial particles released and by the material objects which can interact with the radiation. Some consequences are discussed. Specific energy imparted is defined for a volume, and the definition of absorbed dose as a point function involves the specific energy imparted for a small mass contained in a volume surrounding the point. A possible more precise definition of this volume is suggested and discussed. Conclusions: The importance of absorbed dose motivates a proper definition, and one is given in the present work. No rigorous definition has been presented before.

Grusell, Erik

2015-02-01

239

Oxygen absorbers in food preservation: a review.  

PubMed

The preservation of packaged food against oxidative degradation is essential to establish and improve food shelf life, customer acceptability, and increase food security. Oxygen absorbers have an important role in the removal of dissolved oxygen, preserving the colour, texture and aroma of different food products, and importantly inhibition of food spoilage microbes. Active packaging technology in food preservation has improved over decades mostly due to the sealing of foods in oxygen impermeable package material and the quality of oxygen absorber. Ferrous iron oxides are the most reliable and commonly used oxygen absorbers within the food industry. Oxygen absorbers have been transformed from sachets of dried iron-powder to simple self-adhesive patches to accommodate any custom size, capacity and application. Oxygen concentration can be effectively lowered to 100 ppm, with applications spanning a wide range of food products and beverages across the world (i.e. bread, meat, fish, fruit, and cheese). Newer molecules that preserve packaged food materials from all forms of degradation are being developed, however oxygen absorbers remain a staple product for the preservation of food and pharmaceutical products to reduce food wastage in developed nations and increased food security in the developing & third world. PMID:25829570

Cichello, Simon Angelo

2015-04-01

240

Translatory shock absorber for attitude sensors  

NASA Technical Reports Server (NTRS)

A translatory shock absorber is provided for mounting an attitude sensor thereon for isolating a sensor from translatory vibrations. The translatory shock absorber includes a hollow block structure formed as one piece to form a parallelogram. The absorber block structure includes a movable top plate for supporting the attitude sensor and a fixed base plate with opposed side plates interposed between. At the junctions of the side plates, and the base and top plates, there are provided grooves which act as flexible hinges for attenuating translatory vibrations. A damping material is supported on a pedestal which is carried on the base plate between the side plates thereof. The top of the damping material rests against the bottom surface of the top plate for eliminating the resonant peaks of vibration.

Vonpragenau, G. L.; Morgan, I. T., Jr.; Kirby, C. A. (inventors)

1976-01-01

241

Absorber Materials at Room and Cryogenic Temperatures  

SciTech Connect

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.

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

2011-09-01

242

Optical analysis of solar energy tubular absorbers.  

PubMed

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

Saltiel, C; Sokolov, M

1982-11-15

243

Ferrite HOM Absorber for the RHIC ERL  

SciTech Connect

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.

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

2008-10-01

244

Interference theory of metamaterial perfect absorbers  

E-print Network

The impedance matching in metamaterial perfect absorbers has been believed to involve and rely on magnetic resonant response, with a direct evidence from the anti-parallel directions of surface currents in the metal structures. Here we present a different theoretical interpretation based on interferences, which shows that the two layers of metal structure in metamaterial absorbers are linked only by multiple reflections with negligible near-field interactions or magnetic resonances. This is further supported by the out-of-phase surface currents derived at the interfaces of resonator array and ground plane through multiple reflections and superpositions. The theory developed here explains all features observed in narrowband metamaterial absorbers and therefore provides a profound understanding of the underlying physics.

Chen, Hou-Tong

2011-01-01

245

Cold plasma decontamination of foods.  

PubMed

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

Niemira, Brendan A

2012-01-01

246

Clearing up the clouds around NGC 4151: evidence of a highly ionized absorber  

NASA Astrophysics Data System (ADS)

The Seyfert 1 galaxy NGC 4151 is characterized by complex X-ray absorption, well described by a dual absorber, composed of a uniform mildly ionized gas and a cold system that partially covers the central source. However, in one of the 5 BeppoSAX observations, the spectrum shows two peculiar features. An absorption feature is detected around 8.5-9 keV with a statistical significance of 99.96%. This feature can be fitted either with an absorption edge at E=8.62+0.34-0.52 keV with optical depth ?=0.06±0.03 or with an absorption line with 9.5+1.3-0.6 keV, width ?=0.95+1.2-0.7 keV and EW= 200 eV. In the first case, we associate the feature to highly ionized iron at rest, like FeXXII-FeXXIII ({Erest}=8.4-8.5 keV). In the second case the feature could be identified with a blend of FeXXV and FeXXVI lines, with an outflow velocity v ? (0.09-0.26)c. This spectrum is also characterized by a substantial reduction of the absorption column density and the covering fraction of the dual absorber. In particular the column density of the mildly ionized and cold absorbers is ?3-5 times lower than observed in the other states, and the covering fraction is reduced by ?40 per cent. We propose a possible explanation linking the two properties in terms of a multi-phase ionized absorber.

Piro, L.; de Rosa, A.; Matt, G.; Perola, G. C.

2005-10-01

247

Omnidirectional broadband acoustic absorber based on metamaterials  

NASA Astrophysics Data System (ADS)

We present the design, construction, and experimental characterization of the acoustic analogue of the so called photonic black-hole. The fabricated sample has cylindrical symmetry and consists of two parts, a shell that bends the sound towards the center and a core that dissipates its energy. The shell is made of a metamaterial that perfectly matches the acoustic impedance of air and behaves like a gradient index lens. The experimental data obtained in a multi-modal impedance chamber demonstrate that the proposed acoustic black-hole acts like an onmidirectional broadband absorber with strong absorbing efficiency.

Climente, Alfonso; Torrent, Daniel; Sánchez-Dehesa, José

2012-04-01

248

OSCEE fan exhaust bulk absorber treatment evaluation  

NASA Technical Reports Server (NTRS)

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.

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

1980-01-01

249

Shock-Absorbent Ball-Screw Mechanism  

NASA Technical Reports Server (NTRS)

Actuator containing two ball screws in series employs Belleville springs to reduce impact loads, thereby increasing life expectancy. New application of springs increases reliability of equipment in which ball screws commonly used. Set of three springs within lower screw of ball-screw mechanism absorbs impacts that result when parts reach their upper and lower limits of movement. Mechanism designed with Belleville springs as shock-absorbing elements because springs have good energy-to-volume ratio and easily stacked to attain any stiffness and travel.

Hirr, Otto A., Jr.; Meneely, R. W.

1986-01-01

250

Durability of Polymeric Glazing and Absorber Materials  

SciTech Connect

The Solar Heating and Lighting Program has set the goal of reducing the cost of solar water heating systems by at least 50%. An attractive approach to such large cost reduction is to replace glass and metal parts with less-expensive, lighter-weight, more-integrated polymeric components. The key challenge with polymers is to maintain performance and assure requisite durability for extended lifetimes. We have begun evaluation of several new UV-screened polycarbonate sheet glazing constructions. This has involved interactions with several major polymer industry companies to obtain improved candidate samples. Proposed absorber materials were tested for UV resistance, and appear adequate for unglazed ICS absorbers.

Jorgensen, G.; Terwilliger, K.; Bingham, C.; Lindquist, C.; Milbourne, M.

2005-11-01

251

Advection diffusion equation with absorbing boundary  

E-print Network

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.

John Grant; Michael Wilkinson

2014-12-15

252

Coherent perfect absorber based on metamaterials  

NASA Astrophysics Data System (ADS)

We demonstrate selective coherent perfect absorption based on interaction between bilayered asymmetrically split rings (ASRs) metamaterials and a standing wave formed by two coherent counter propagating beams. The selective coherent perfect absorbers with high absorption have been achieved depending on the phase difference between two coherent beams. The selective coherent control absorbers can be well designed by changing the thickness of the dielectric layer and the asymmetry of the ASRs. The coherently controlled metamaterials provide an opportunity to realize selective multiband absorption and ultrafast information processing.

Nie, Guangyu; Shi, Quanchao; Zhu, Zheng; Shi, Jinhui

2014-11-01

253

Design optimization of nanostrip metamaterial perfect absorbers  

NASA Astrophysics Data System (ADS)

Metamaterial perfect absorber (MPA) promises many applications due to its capability of complete suppression of transmission or/and reflection. The complete dissipation of the incident electromagnetic energy by the absorptive meta-atoms makes it a unique candidate in many photonic and optoelectronic devices. An ultrathin metamaterial absorber that consists of a periodic nanostrip metal on top of a planar dielectric slab backed by a conducting metal plate is presented. The spectral absorptivity of MPA is investigated by the finite difference time domain method from visible to near-infrared. The various geometrical and material parameters of MPA are optimized for maximum absorption.

El-Aasser, Mostafa A.

2014-01-01

254

Zitterbewegung in Cold Atoms  

NASA Astrophysics Data System (ADS)

In condensed matter systems, the coupling between spatial and spin degrees of freedom through the spin-orbit (SO) interaction offers the possibility of manipulating the electron spin via its orbital motion. The proposal by Datta and Das [1,2] of a `spin transistor' for example, highlights the use of the SO interaction to control the electron spin via electrical means. Recently, arrangements of crossed lasers and magnetic fields have been used to trap and cool atoms in optical lattices and also to create light-induced gauge potentials [3], which mimic the SO interactions in real solids. In this work, we investigate the Zitterbewegung in cold atoms by starting from the effective SO Hamiltonian derived in Ref. [4]. Cross-dressed atoms as effective spins can provide a proper setting in which to observe this effect, as the relevant parameter range of SO strengths may be more easily attainable in this context. We find a variety of peculiar Zitterbewegung orbits in real and pseudo-spin spaces, e.g., cycloids and ellipses - all of which obtained with realistic parameters.[4pt] [1] S. Datta and B. Das, Appl. Phys. Lett. 56, 655 (1990);[0pt] [2] J. Carlos Egues, et. al., Appl. Phys. Lett. 82, 2658 (2003);[0pt] [3] Y. -J. Lin, et. al, Nature 471, 83 (2011);[0pt] [4] Jay D. Sau, et. al, PRB 83, 140510(R) (2010).

Penteado, Poliana; Egues, J. Carlos

2013-03-01

255

Cold Spring Harbor Laboratory  

NSDL National Science Digital Library

Established in 1890, the Cold Spring Harbor Laboratory (CSHL) is one of the best-known and most respected private research institutions in the United States. Over the past century, the Laboratory has supported the careers of seven Nobel Prize recipients and it is particularly well-regarded for its work in the field of genetics research. Today, there are over 400 scientists who work at the facility in Long Island, and their work ranges across the areas of cancer, neuroscience, genomics, and bioinformatics. Their website is a cornucopia of information on their activities, and first-time visitors should start by reading over the "CSHL Headlines" scrolling updates on the homepage. After that, they can look at the "Research" section. Here they will find overviews of their primary research groups and links to some of their specialized facilities, like the Dolan DNA Learning Center. Most visitors will want to visit the "Library and Archives" section. Here they can learn about CSHL authors' publications and look through the digital collections. The digital collections include tributes to Barbara McClintock, who was awarded the Nobel Prize in 1983, and who worked at the Laboratory for four decades.

256

The Role of Gas in the Merging of Massive Black Holes in Galactic Nuclei. II. Black Hole Merging in a Clumpy Disk  

E-print Network

Using SPH numerical simulations, we investigate the effects of gas on the inspiral and merger of a massive black hole binary. This study is motivated by the very massive nuclear gas disks observed in the central regions of merging galaxies. Here we present results that expand on the treatment in a previous work (Escala, Larson, Coppi & Mardones 2004; henceforth Paper I), by studying more realistic models. We run a variety of models, ranging from simulations with a relatively smooth gas disk to cases in which the gas has a more clumpy spatial distribution. We also vary the inclination angle between the plane of the binary and the plane of the disk, and the mass ratio between the MBHs and the gaseous disk. We find that as in Paper I, in the early evolution of the system the binary separation diminishes due to gravitational drag, and in the later stages the medium responds by forming an ellipsoidal density enhancement whose axis lags behind the binary axis; this offset produces a torque on the binary that causes continuing loss of angular momentum and is able to reduce the separation to distances where gravitational radiation is efficient. In the simulations that we perform, we find that the coalescence timescale for the MBH binary varies between 5 10^6 yr and 2.5 10^7 yr. For MBHs that satisfy the observed `m-sigma_c' relation, we predict that in a merger of galaxies that have at least 1% of their total mass in gas, the MBHs will coalesce soon after the galaxies merge. We also predict that if the MBHs depart from the `m-sigma_c' relation, the MBH binary can create a circumbinary gap in the disk that stalls the coalescence, but this gap formation can act as a self-regulatory mechanism on MBH growth that can help to explain the existence of the `m-sigma_c' relation.

Andres Escala; Richard B. Larson; Paolo S. Coppi; Diego Mardones

2004-06-11

257

A Waldenström macroglobulin that is both a cold agglutinin and a cryoglobulin because it binds N-acetylneuraminosyl residues  

PubMed Central

A purified human monoclonal IgM(?) (cold agglutinin MKV) has been characterized as both a cold agglutinin and a cryoglobulin. Since its reactivity with human erythrocytes but not with dog erythrocytes is reduced by treatment of the cells with ficin and its reactivity with both is abolished by treatment of the cells with neuraminidase, it has by definition Pr2 specificity [Roelcke, D. (1974) Clin. Immunol. Immunopath. 2, 266-280]. Presumably, the membrane receptors for cold agglutinin MKV are sialic acid-containing glycoproteins in human cells and sialic acid-containing glycolipids in dog cells. Agglutination of erythrocytes is specifically inhibited by II3-N-acetylneuraminosyllactosylceramide (GM3) and N-acetylneuraminosylparagloboside but not by their N-glycolylneuraminosyl forms or by lactosylceramide or paragloboside, and the reactivity of neuraminidase-treated cells can be restored by allowing them to absorb either GM3 or N-acetylneuraminosylparagloboside. When large amounts of ganglioside are absorbed, the cells are agglutinated not only in the cold, but also at 37°, showing that the density of receptor sites on the erythrocyte surface can influence the thermal amplitude of cold agglutinins. Liberation of sialic acid from cold agglutinin MKV by treatment with neuraminidase (acylneuraminosyl hydrolase; EC 3.2.1.18) does not affect its agglutinating properties but the asialoprotein is no longer a cryoglobulin. Apparently the physical basis for its precipitation in the cold is the intermolecular immune binding of N-acetylneuraminosyl residues. PMID:412191

Tsai, Chao-Ming; Zopf, David A.; Yu, Robert K.; Wistar, Richard; Ginsburg, Victor

1977-01-01

258

Plants in a cold climate.  

PubMed Central

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

Smallwood, Maggie; Bowles, Dianna J

2002-01-01

259

Nonfreezing cold-induced injuries.  

PubMed

Non-freezing cold injury (NFCI) is the Cinderella of thermal injuries and is a clinical syndrome that occurs when tissues are exposed to cold temperatures close to freezing point for sustained periods. NFCI is insidious in onset, often difficult to recognize and problematic to treat, and yet the condition accounts for significant morbidity in both military and civilians who work in cold conditions. Consequently recognition of those at risk, limiting their exposure and the appropriate and timely use of suitable protective equipment are essential steps in trying to reduce the impact of the condition. This review addresses the issues surrounding NFCI. PMID:21465916

Imray, C H E; Richards, P; Greeves, J; Castellani, J W

2011-03-01

260

Dealing with Cold Weather Injuries  

MedlinePLUS

... this page, please enable JavaScript. Dealing With Cold Weather Injuries Safety precautions can prevent serious problems during ... clothing should be removed and replaced with warm, dry clothes or blankets. People with hypothermia should also ...

261

Protecting Workers from Cold Stress  

MedlinePLUS

... you on cold stress hazards and prevention. • Provide engineering controls, e.g., radiant heaters. • Gradually introduce workers ... to rewarm the area unless directed by medical personnel. For Trench (Immersion) Foot: • Remove wet shoes/socks; ...

262

Prescription Drugs and Cold Medicines  

MedlinePLUS

... Cold Medicines Email Facebook Twitter What is Prescription Drug Abuse: Some medications have psychoactive (mind-altering) properties and, ... Unused Medicines: What You Should Know (FDA) Prescription Drug Abuse Learn what you can do to prevent medicine ...

263

Sustainable acoustic absorbers from the biomass  

Microsoft Academic Search

There is currently considerable interest in developing sustainable absorbers, either from biomass materials or recycled materials, and it is the former that is the subject of this paper. A number of potential candidate materials are available from the biomass in the form of organic fibres. Non-fibrous materials, such as configurations of whole straw or reed, can also act as sound

David J. Oldham; Christopher A. Egan; Richard D. Cookson

2011-01-01

264

Torus elements used in effective shock absorber  

NASA Technical Reports Server (NTRS)

Energy absorbing device forces torus elements to revolve annularly between two concentric tubes when a load is applied to one tube. Interference forces can be varied by using torus elements of different thicknesses. The device operates repeatedly in compression or tension, and under problems of large onset rate tolerance or structural overload.

Cunningham, P.; Platus, D. L.

1966-01-01

265

How to build a molecular shock absorber.  

PubMed

Newly determined structures of the alpha-helical repeats that make up the key 'rod' domains of spectrin and alpha-actinin - which serve as spacers between their actin-binding domains - have provided important insights into how these proteins function as molecular shock absorbers in cells. PMID:10607557

McGough, A

1999-12-01

266

Shock absorbing mount for electrical components  

NASA Technical Reports Server (NTRS)

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.

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

1975-01-01

267

Shock absorber protects motive components against overloads  

NASA Technical Reports Server (NTRS)

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.

1965-01-01

268

Novel shock absorber features varying yield strengths  

NASA Technical Reports Server (NTRS)

A shock absorbent webbing of partially drawn synthetic strands is arranged in sections of varying density related to the varying mass of the human body. This is contoured to protect the body at points of contact, when subjected to large acceleration or deceleration forces.

Geier, D. J.

1964-01-01

269

Do Different Colors Absorb Heat Better?  

NSDL National Science Digital Library

Students test whether the color of a material affects how much heat it absorbs. They leave ice cubes placed in boxes made of colored paper (one box per color; white, yellow, red and black) in the sun, and predict in which colored box ice cubes melt first. They record the order and time required for the ice cubes to melt.

2014-09-18

270

Aldehyde-containing urea-absorbing polysaccharides  

NASA Technical Reports Server (NTRS)

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.

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

1977-01-01

271

Characterization of porous absorbent materials P. Leclaire  

E-print Network

Characterization of porous absorbent materials P. Leclaire LRMA-DRIVE, ISAT, 49 rue Mademoiselle and experimental research on the acoustical properties of air-saturated porous materials for engineering-saturated porous materials is of great importance for sound insulation and vibration damping applications. Over

Paris-Sud XI, Université de

272

Novel absorber materials for EUV lithography mask  

NASA Astrophysics Data System (ADS)

One of main issues of EUV lithography is to reduce so-called shadowing effect attributed to oblique incidence of EUV light on a mask. In order to mitigate shadowing, a thinner absorber layer thickness for EUV mask is preferred. In order to realize EUV masks with thinner absorber stack, we introduced SnO film as a high absorptive material for EUV light. Thorough actual measurement of EUV reflectance and subsequent data fitting to theoretical curve, we confirmed that SnO has large k (extinction coefficient) value. As a result, SnO absorber can do with about a half thickness compared to Ta-based absorber having the same OD value. Using SnO film, we designed a binary mask consisting of SnO/CrN-buffer pattern and an att.PSM consisting of SnO/Ru-shifter pattern. SnO has also considerable transparency in the range of DUV wavelength for use of defect inspection. We confirmed both binary mask and att.PSM have low reflectance in the range of DUV wavelength even without top AR coating. The att.PSM can realize appropriate reflectance (nearby 6%) at a phase shift of 180 deg with the total patterned (SnO/Ru) thickness of below 41 nm even with 6 nm thick SiN top coating. Furthermore, we evaluated dry etched cross sectional profile of the binary mask and the att.PSM. The initial etch profiles look encouraging.

Matsuo, Tadashi; Kanayama, Koichiro; Okumoto, Yasuhiro

2009-04-01

273

Absorbing covers and intransitive non-interference  

Microsoft Academic Search

The paper gives necessary and sufficient conditions for a system to satisfy intransitive non-interference. Security is defined in terms of allowable flows of information among action domains as represented by an interferes relation ~>. We examine properties of special sets called basis elements generated from the relation ~> and introduce the notion of absorbing covers which is associated with the

Sylvan Pinsky

1995-01-01

274

Integrated tuned vibration absorbers: a theoretical study.  

PubMed

This article presents a simulation study on two integrated tuned vibration absorbers (TVAs) designed to control the global flexural vibration of lightly damped thin structures subject to broad frequency band disturbances. The first one consists of a single axial switching TVA composed by a seismic mass mounted on variable axial spring and damper elements so that the characteristic damping and natural frequency of the absorber can be switched iteratively to control the resonant response of three flexural modes of the hosting structure. The second one consists of a single three-axes TVA composed by a seismic mass mounted on axial and rotational springs and dampers, which are arranged in such a way that the suspended mass is characterized by uncoupled heave and pitch-rolling vibrations. In this case the three damping and natural frequency parameters of the absorber are tuned separately to control three flexural modes of the hosting structure. The simulation study shows that the proposed single-unit absorbers produce, respectively, 5.3 and 8.7?dB reductions of the global flexural vibration of a rectangular plate between 20 and 120?Hz. PMID:24180774

Gardonio, Paolo; Zilletti, Michele

2013-11-01

275

ABSORBING BOUNDARY CONDITIONS FOR ELECTROMAGNETIC WAVE PROPAGATION  

E-print Network

ABSORBING BOUNDARY CONDITIONS FOR ELECTROMAGNETIC WAVE PROPAGATION Xiaobing Feng y Abstract of the electromagnetic fields indi­ vidually. This boundary condition allows any wave motion generated within the domain, and the electromagnetic wave scattering related to antennas. Because of the limitations of both speed and memory

276

Influence of Absorbers on the Electromagnetic Radiation  

E-print Network

The phenomenon of the electromagnetic absorption by arbitrarily distributed discrete absorbers is analyzed from the photon point of view. It is shown that apart from the decrease in the intensity of the signal the net effect of absorption includes a relative increase in the photon bunching.

Neil V. Budko

2007-12-05

277

Semiconductor Nanowire Optical Antenna Solar Absorbers  

E-print Network

technology. KEYWORDS Solar cell, semiconductor nanowires, optical antennas, photon management, light trapping based on resonant cavities,7 plasmon- ics,8 and photonic crystals5,9 have recently gained significantSemiconductor Nanowire Optical Antenna Solar Absorbers Linyou Cao, Pengyu Fan, Alok P. Vasudev

Fan, Shanhui

278

Oil-absorbent cellulosic derivatives. Patent Application  

Microsoft Academic Search

Considerable research has been devoted to developing oil absorbents for cleanup of oil spills and removal of emulsified oil from waste water. Agricultural products and residues have been used for these applications, and these materials have the advantage of being inexpensive and readily available. Mats and column packings for oil removal have also been prepared by mixing cellulosic fibers with

G. F. Fanta; W. M. Doane

1985-01-01

279

Tuned mass absorber on a flexible structure  

NASA Astrophysics Data System (ADS)

The classic design of a tuned mass absorber is based on a simple two-mass analogy in which the tuned mass is connected to the structural mass with a spring and a viscous damper. In a flexible multi-degree-of-freedom structure the tuned mass absorber is typically introduced to provide damping of a specific mode. The motion of the point of attachment of the tuned mass absorber to the structure has not only a contribution from the targeted mode, but also a background contribution from other non-resonant modes. Similarly, the force provided by the tuned mass absorber is distributed between the targeted mode and the background modes. It is demonstrated how this effect can be included via a non-dimensional dynamic background flexibility coefficient, extracted from a classic modal analysis for the particular frequency of the selected mode. An explicit calibration procedure is developed starting with the desired maximum amplification, from which the device damper, mass and stiffness are determined, accounting for the background flexibility. Examples demonstrate the influence of the flexibility effect and the efficiency of the proposed procedure.

Krenk, Steen; Høgsberg, Jan

2014-03-01

280

Composition for absorbing hydrogen from gas mixtures  

DOEpatents

A hydrogen storage composition is provided which defines a physical sol-gel matrix having an average pore size of less than 3.5 angstroms which effectively excludes gaseous metal hydride poisons while permitting hydrogen gas to enter. The composition is useful for separating hydrogen gas from diverse gas streams which may have contaminants that would otherwise render the hydrogen absorbing material inactive.

Heung, Leung K. (Aiken, SC); Wicks, George G. (Aiken, SC); Lee, Myung W. (Aiken, SC)

1999-01-01

281

Moving core beam energy absorber and converter  

DOEpatents

A method and apparatus for the prevention of overheating of laser or particle beam impact zones through the use of a moving-in-the-coolant-flow arrangement for the energy absorbing core of the device. Moving of the core spreads the energy deposition in it in 1, 2, or 3 dimensions, thus increasing the effective cooling area of the device.

Degtiarenko, Pavel V.

2012-12-18

282

Perfect terahertz absorber using fishnet based metafilm  

Microsoft Academic Search

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

Abul Kalam Azad; Dmitry Yu Shchegolkov; Houtong Chen; Antoinette Taylor; E I Smirnova; John F O Hara

2009-01-01

283

A broadband low-reflection metamaterial absorber  

Microsoft Academic Search

Artificially engineered metamaterials have enabled the creation of electromagnetic materials with properties not found in nature. Recent work has demonstrated the feasibility of developing high performance, narrowband electromagnetic absorbers using such metamaterials. These metamaterials derive their absorption properties primarily through dielectric loss and impedance matching at resonance. This paper builds on that work by increasing the bandwidth through embedding resistors

S. Gu; J. P. Barrett; T. H. Hand; B.-I. Popa; S. A. Cummer

2010-01-01

284

Spectral absorbance of benthic cladoceran carapaces as a new method for inferring past UV exposure of aquatic biota  

NASA Astrophysics Data System (ADS)

We developed a method for measuring fossil cladoceran (Branchiopoda) carapace absorbance to infer past ultraviolet radiation (UV) exposure in lakes. This was done under the presumptions that cladocerans synthesize photoprotective compounds, of which melanin is the main UV-absorbing pigment, to their exoskeletons and melanin is preserved in sedimentary cladoceran remains. We extracted large-sized cladoceran (benthic Alona spp.) carapaces from subsections of sediment cores from two environmentally divergent lakes; a humic boreal forest lake in eastern Finland (past 1500 years) and a clear-water mountain lake in the Austrian Alps (past 300 years). We measured the absorbance of extracted carapaces with a spectrophotometer under visible light and UV wavelengths using an adapter, which was designed to hold the microfossils. When compared to the spectrum of synthetic melanin, the shapes of absorbance spectra at the 700-280 nm range suggested that the fossil carapaces contained melanin. The carapace absorbance under UV throughout the sediment cores was significantly higher in the clear-water alpine lake than in the humic boreal lake reflecting differences in the general underwater UV and optical environments between the sites. In addition, carapace absorbance was significantly higher during the Little Ice Age (LIA) than during pre- or post-LIA periods in both lakes. In the alpine lake, this was most likely a response to increased underwater UV induced by reduced primary production and more transparent water column during the cold summers of LIA, whereas reduced input of carbon compounds from the catchment through elongated permafrost and ice-cover periods likely induced higher water transparency in the boreal lake during this cold climate phase. We conclude that fossil melanin provides a good estimation of past underwater UV exposure in lakes with large cladoceran carapaces preserved in sediments and that the method introduced here is easy and cost- and time-efficient technique to be widely used in paleoaquatic UV inferences.

Nevalainen, Liisa; Rautio, Milla

2014-01-01

285

Biomolecular Effects of Cold Plasma Exposure  

NASA Technical Reports Server (NTRS)

The effects of cold plasma exposure on Deinococcus radiodurans, plasmid DNA and model proteins were assessed using microbiological, spectrometric and biochemical techniques. Exposure of D. radiodurans, an extremely radiation resistant microbe, to O2 plasma (less than or equal to 25 W, approx. 45 mTorr, 90 min) yielded a approx. 99.999 % sterilization and the sterilization rate was increased approx. 10-fold at 100 W and 500 mTorr. AFM images shows that the exposed cells are significantly deformed and possess 50-70 nm concavities. IR analysis indicates the chemical degradation of lipids, proteins and carotenoids of the cell wall and membrane. Intracellular damage was indicated by major absorbance loss at 1245, 1651 and 1538/cm corresponding to degradation of DNA and proteins, respectively. Biochemical experiments demonstrate that plasmas induce strand scissions and crosslinking of plasmid DNA, and reduction of enzyme activity; the degradation is power dependent with total sample loss occurring in 60 s at 200 W and 500 mTorr. Emission spectroscopy shows that D. radiodurans is volatilized into CO2, CO, N2 and H2O confirming the removal of biological matter from contaminated surfaces. The O2 plasma impacts several cellular components predominantly through chemical degradation by atomic oxygen. A CO2, plasma, however, was not effective at degrading D. radiodurans, revealing the importance of plasma composition, which has implications for planetary protection and the contamination of Mars.

Mogul, Rakesh; Bolshakov, Alexander A.; Chan, Suzanne L.; Stevens, Ramsey D.; Khare, Bishun N.; Meyyappan, M.; Trent, Jonathan D.; DeVincenzi, D. (Technical Monitor)

2002-01-01

286

Antibiotic use for common cold  

Microsoft Academic Search

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

Timothy W. Kenealy; Bruce Arroll

287

Sinusitis in the common cold  

Microsoft Academic Search

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

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

288

COLD-SAT dynamic model  

Microsoft Academic Search

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

Neil S. Adams; Gary Bollenbacher

1992-01-01

289

Reexamining the Cold Conveyor Belt  

Microsoft Academic Search

Despite the popularity of the conveyor-belt model for portraying the airflow through midlatitude cyclones, questions arise as to the path of the cold conveyor belt, the lower-tropospheric airflow poleward of and underneath the warm front. Some studies, beginning with Carlson's analysis of the eastern U.S. cyclone of 5 December 1977, depict the cold conveyor belt moving westward, reaching the northwest

David M. Schultz

2001-01-01

290

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

DOEpatents

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.

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

2014-12-02

291

Urolithiasis on absorbable and non-absorbable suture materials in the rabbit bladder.  

PubMed

Absorbable and non-absorbable suture materials were evaluated for calculi formation and tissue reactivity in the rabbit bladder. Five-O chromic, polydioxinone and polypropylene sutures were used to close cystostomies made in New Zealand white rabbits. Bladders were evaluated at 15, 30, 60 and 90 days. Calculi formed on all sutures tested and the persistence of calculi appeared to be dependent on the longevity of the suture material used. This data suggests that the use of non-absorbable suture material in urologic surgery may contribute to calculus formation. PMID:3080609

Morris, M C; Baquero, A; Redovan, E; Mahoney, E; Bannett, A D

1986-03-01

292

Molecular basis of cold adaptation.  

PubMed Central

Cold-adapted, or psychrophilic, organisms are able to thrive at low temperatures in permanently cold environments, which in fact characterize the greatest proportion of our planet. Psychrophiles include both prokaryotic and eukaryotic organisms and thus represent a significant proportion of the living world. These organisms produce cold-evolved enzymes that are partially able to cope with the reduction in chemical reaction rates induced by low temperatures. As a rule, cold-active enzymes display a high catalytic efficiency, associated however, with a low thermal stability. In most cases, the adaptation to cold is achieved through a reduction in the activation energy that possibly originates from an increased flexibility of either a selected area or of the overall protein structure. This enhanced plasticity seems in turn to be induced by the weak thermal stability of psychrophilic enzymes. The adaptation strategies are beginning to be understood thanks to recent advances in the elucidation of the molecular characteristics of cold-adapted enzymes derived from X-ray crystallography, protein engineering and biophysical methods. Psychrophilic organisms and their enzymes have, in recent years, increasingly attracted the attention of the scientific community due to their peculiar properties that render them particularly useful in investigating the possible relationship existing between stability, flexibility and specific activity and as valuable tools for biotechnological purposes. PMID:12171655

D'Amico, Salvino; Claverie, Paule; Collins, Tony; Georlette, Daphné; Gratia, Emmanuelle; Hoyoux, Anne; Meuwis, Marie-Alice; Feller, Georges; Gerday, Charles

2002-01-01

293

Cool Outflows and HI absorbers with SKA  

E-print Network

HI 21-cm absorption spectroscopy provides a unique probe of the cold neutral gas in normal and active galaxies from redshift z > 6 to the present day. We describe the status of HI absorption studies, the plans for pathfinders/precursors, the expected breakthroughs that will be possible with SKA1, and some limitations set by the current design.

Morganti, Raffaella; Curran, Stephen J; Members, the SKA HI SWG

2015-01-01

294

Cold War Entanglements of Social ANDY BYFORD  

E-print Network

in particular) and political agents of all hues in post-war America. In this context `the Cold War' is madeREVIEW Cold War Entanglements of Social Science ANDY BYFORD MLAC, Durham University, UK Cold War.00. The Cold War era the three decades between the end of the Second World War and the end of the Vietnam War

Solovey, Mark

295

Garlic for the common cold.  

PubMed

Background Garlic is alleged to have antimicrobial and antiviral properties that relieve the common cold, among other beneficial effects. There is widespread usage of garlic supplements. The common cold is associated with significant morbidity and economic consequences. On average, children have six to eight colds per year and adults have two to four.Objectives To determine whether garlic (Allium sativum) is effective for the prevention or treatment of the common cold, when compared to placebo, no treatment or other treatments.Search methods We searched CENTRAL (2014, Issue 7),OLDMEDLINE (1950 to 1965),MEDLINE (January 1966 to July week 5, 2014), EMBASE(1974 to August 2014) and AMED (1985 to August 2014).Selection criteria Randomised controlled trials of common cold prevention and treatment comparing garlic with placebo, no treatment or standard treatment.Data collection and analysis Two review authors independently reviewed and selected trials from searches, assessed and rated study quality and extracted relevant data.Main results In this updated review, we identified eight trials as potentially relevant from our searches. Again, only one trial met the inclusion criteria.This trial randomly assigned 146 participants to either a garlic supplement (with 180 mg of allicin content) or a placebo (once daily)for 12 weeks. The trial reported 24 occurrences of the common cold in the garlic intervention group compared with 65 in the placebo group (P value < 0.001), resulting in fewer days of illness in the garlic group compared with the placebo group (111 versus 366). The number of days to recovery from an occurrence of the common cold was similar in both groups (4.63 versus 5.63). Only one trial met the inclusion criteria, therefore limited conclusions can be drawn. The trial relied on self reported episodes of the common cold but was of reasonable quality in terms of randomisation and allocation concealment. Adverse effects included rash and odour. Authors' conclusions There is insufficient clinical trial evidence regarding the effects of garlic in preventing or treating the common cold. A single trial suggested that garlic may prevent occurrences of the common cold but more studies are needed to validate this finding. Claims of effectiveness appear to rely largely on poor-quality evidence. PMID:25386977

Lissiman, Elizabeth; Bhasale, Alice L; Cohen, Marc

2014-01-01

296

EDITORIAL: Cold Quantum GasesEditorial: Cold Quantum Gases  

NASA Astrophysics Data System (ADS)

This Special Issue of Journal of Optics B: Quantum and Semiclassical Optics brings together the contributions of various researchers working on theoretical and experimental aspects of cold quantum gases. Different aspects of atom optics, matter wave interferometry, laser manipulation of atoms and molecules, and production of very cold and degenerate gases are presented. The variety of subjects demonstrates the steadily expanding role associated with this research area. The topics discussed in this issue, extending from basic physics to applications of atom optics and of cold atomic samples, include: bulletBose--Einstein condensation bulletFermi degenerate gases bulletCharacterization and manipulation of quantum gases bulletCoherent and nonlinear cold matter wave optics bulletNew schemes for laser cooling bulletCoherent cold molecular gases bulletUltra-precise atomic clocks bulletApplications of cold quantum gases to metrology and spectroscopy bulletApplications of cold quantum gases to quantum computing bulletNanoprobes and nanolithography. This special issue is published in connection with the 7th International Workshop on Atom Optics and Interferometry, held in Lunteren, The Netherlands, from 28 September to 2 October 2002. This was the last in a series of Workshops organized with the support of the European Community that have greatly contributed to progress in this area. The scientific part of the Workshop was managed by A Hemmerich, W Hogervorst, W Vassen and J T M Walraven, with input from members of the International Programme Committee who are listed below. The practical aspects of the organization were ably handled by Petra de Gijsel from the Vrije Universiteit in Amsterdam. The Workshop was funded by the European Science Foundation (programme BEC2000+), the European Networks 'Cold Quantum Gases (CQG)', coordinated by E Arimondo, and 'Cold Atoms and Ultraprecise Atomic Clocks (CAUAC)', coordinated by J Henningsen, by the German Physical Society (DFG), by the Dutch Foundation for Fundamental Research on Matter (FOM) and by the Dutch Gelderland province. We thank all these sponsors and the members of the International Programme Committee for making the Workshop such a success. At this point we take the opportunity to express our gratitude to both authors and reviewers, for their efforts in preparing and ensuring the high quality of the papers in this special issue. Wim Vassen Vrije Universiteit, Amsterdam Andreas Hemmerich Universität Hamburg Ennio Arimondo Università di Pisa Guest Editors International Programme Committee A Aspect Orsay, France E Cornell Boulder, USA W Ertmer Hannover, Germany T W Haensch Munich, Germany A Hemmerich Hamburg, Germany W Hogervorst Amsterdam, The Netherlands D Kleppner Cambridge, USA C Salomon Paris, France G V Shlyapnikov Amsterdam, Paris, Moscow S Stringari Trento, Italy W Vassen Amsterdam, The Netherlands J T M Walraven Amsterdam, The Netherlands

Vassen, W.; Hemmerich, A.; Arimondo, E.

2003-04-01

297

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

Microsoft Academic Search

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

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

2007-01-01

298

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

Microsoft Academic Search

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

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

2007-01-01

299

Optimization of sound absorbing performance for gradient multi-layer-assembled sintered fibrous absorbers  

NASA Astrophysics Data System (ADS)

The transfer matrix method, based on plane wave theory, of multi-layer equivalent fluid is employed to evaluate the sound absorbing properties of two-layer-assembled and three-layer-assembled sintered fibrous sheets (generally regarded as a kind of compound absorber or structures). Two objective functions which are more suitable for the optimization of sound absorption properties of multi-layer absorbers within the wider frequency ranges are developed and the optimized results of using two objective functions are also compared with each other. It is found that using the two objective functions, especially the second one, may be more helpful to exert the sound absorbing properties of absorbers at lower frequencies to the best of their abilities. Then the calculation and optimization of sound absorption properties of multi-layer-assembled structures are performed by developing a simulated annealing genetic arithmetic program and using above-mentioned objective functions. Finally, based on the optimization in this work the thoughts of the gradient design over the acoustic parameters- the porosity, the tortuosity, the viscous and thermal characteristic lengths and the thickness of each samples- of porous metals are put forth and thereby some useful design criteria upon the acoustic parameters of each layer of porous fibrous metals are given while applying the multi-layer-assembled compound absorbers in noise control engineering.

Zhang, Bo; Zhang, Weiyong; Zhu, Jian

2012-04-01

300

Optimization of sound absorbing performance for gradient multi-layer-assembled sintered fibrous absorbers  

NASA Astrophysics Data System (ADS)

The transfer matrix method, based on plane wave theory, of multi-layer equivalent fluid is employed to evaluate the sound absorbing properties of two-layer-assembled and three-layer-assembled sintered fibrous sheets (generally regarded as a kind of compound absorber or structures). Two objective functions which are more suitable for the optimization of sound absorption properties of multi-layer absorbers within the wider frequency ranges are developed and the optimized results of using two objective functions are also compared with each other. It is found that using the two objective functions, especially the second one, may be more helpful to exert the sound absorbing properties of absorbers at lower frequencies to the best of their abilities. Then the calculation and optimization of sound absorption properties of multi-layer-assembled structures are performed by developing a simulated annealing genetic arithmetic program and using above-mentioned objective functions. Finally, based on the optimization in this work the thoughts of the gradient design over the acoustic parameters- the porosity, the tortuosity, the viscous and thermal characteristic lengths and the thickness of each samples- of porous metals are put forth and thereby some useful design criteria upon the acoustic parameters of each layer of porous fibrous metals are given while applying the multi-layer-assembled compound absorbers in noise control engineering.

Zhang, Bo; Zhang, Weiyong; Zhu, Jian

2011-11-01

301

Development and application of rotary shock absorber  

SciTech Connect

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.

Yamamoto, Kozo; Yamada, Toshihiro; Fukuyama, Katsura

1995-12-31

302

Shock wave absorber having apertured plate  

DOEpatents

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.

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

1983-08-26

303

Shock wave absorber having apertured plate  

DOEpatents

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.

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

1985-01-01

304

Mechanically stretchable and tunable metamaterial absorber  

NASA Astrophysics Data System (ADS)

In this letter, we present experimental demonstration of a mechanically stretchable and tunable metamaterial absorber composed of dielectric resonator stacked on a thin conductive rubber layer. A near unity absorption is observed due to strong local field confinement around magnetic Mie resonance of dielectric resonator. Furthermore, the interspacing between unit cells is modulated dynamically under uniaxial stress. Owing to the decreases of longitudinal coupling between neighboring unit cells, the resonant absorption peak is reversibly tuned by 410 MHz, as the stain varies up to 180% along H field direction. On the contrary, the resonant absorption state is nearly independent on strain variation when external stress is applied along E field direction, due to the weak transverse interplaying. The mechanically tunable metamaterial absorber featured by flexibility paves a way forwards for actual application.

Zhang, Fuli; Feng, Shuqi; Qiu, Kepeng; Liu, Zijun; Fan, Yuancheng; Zhang, Weihong; Zhao, Qian; Zhou, Ji

2015-03-01

305

Investigations on Absorber Materials at Cryogenic Temperatures  

SciTech Connect

In the framework of the 12 GeV upgrade project for the Continuous Electron Beam Accelerator Facility (CEBAF) improvements are being made to refurbish cryomodules housing Thomas Jefferson National Accelerator Facility?s (JLab) original 5-cell cavities. Recently we have started to look into a possible simplification of the existing Higher Order Mode (HOM) absorber design combined with the aim to find alternative material candidates. The absorbers are implemented in two HOM-waveguides immersed in the helium bath and operate at 2 K temperature. We have built a cryogenic setup to perform measurements on sample load materials to investigate their lossy characteristics and variations from room temperature down to 2 K. Initial results are presented in this paper.

Frank Marhauser, Thomas Elliott, Robert Rimmer

2009-05-01

306

Disposable Diaper Absorbency: Improvements via Advanced Designs.  

PubMed

Absorbency effectiveness in diapers has improved significantly in recent years with the advent of new ingredient combinations and advanced design features. With these features, many leading products maintain their dryness performance overnight. Considering the importance of holding liquid away from the skin, ongoing research in diaper construction focuses on strategies to increase the effectiveness to capture liquid and help avoid rewetting of infant skin. The layout and design of a disposable diaper allows for distribution of absorbency features where they can provide the optimal benefit. Clinical evidence indicates materials can keep moisture away from the skin in the diapered area, helping maintain proper skin hydration, minimizing irritation, and contributing to reduced rates of diaper rash. PMID:24961785

Helmes, C Tucker; O'Connor, Robert; Sawyer, Larry; Young, Sharon

2014-06-24

307

Impedance matched thin metamaterials make metals absorbing  

PubMed Central

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. PMID:24220284

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

2013-01-01

308

A broadband low-reflection metamaterial absorber  

NASA Astrophysics Data System (ADS)

Artificially engineered metamaterials have enabled the creation of electromagnetic materials with properties not found in nature. Recent work has demonstrated the feasibility of developing high performance, narrowband electromagnetic absorbers using such metamaterials. These metamaterials derive their absorption properties primarily through dielectric loss and impedance matching at resonance. This paper builds on that work by increasing the bandwidth through embedding resistors into the metamaterial structure in order to lower the Q factor and by using multiple elements with different resonances. This is done while maintaining an impedance-matched material at normal incidence. We thus present the design, simulation, and experimental verification of a broadband gigahertz region metamaterial absorber, with a maximum absorption of 99.9% at 2.4 GHz, and a full width at half maximum bandwidth of 700 MHz, all while maintaining low reflection inside and outside of resonance.

Gu, S.; Barrett, J. P.; Hand, T. H.; Popa, B.-I.; Cummer, S. A.

2010-09-01

309

Cold accretion flows and the nature of high column density H I absorption at redshift 3  

NASA Astrophysics Data System (ADS)

Simulations predict that galaxies grow primarily through the accretion of gas that has not gone through an accretion shock near the virial radius and that this cold gas flows towards the central galaxy along dense filaments and streams. There is, however, little observational evidence for the existence of these cold flows. We use a large, cosmological, hydrodynamical simulation that has been post-processed with radiative transfer to study the contribution of cold flows to the observed z= 3 column density distribution of neutral hydrogen, which our simulation reproduces. We find that nearly all of the H I absorption arises in gas that has remained colder than 105.5 K, at least while it was extragalactic. In addition, the majority of the H I is falling rapidly towards a nearby galaxy, with non-negligible contributions from outflowing and static gas. Above a column density of ? cm-2, most of the absorbers reside inside haloes, but the interstellar medium only dominates for ? cm-2. Haloes with total mass below 1010 M? dominate the absorption for ? cm-2, but the average halo mass increases sharply for higher column densities. Although very little of the H I in absorbers with ? cm-2 resides inside galaxies, systems with ? cm-2 are closely related to star formation: most of their H I either will become part of the interstellar medium before z= 2 or has been ejected from a galaxy at z > 3. Cold accretion flows are critical for the success of our simulation in reproducing the observed rate of incidence of damped Lyman-? and particularly that of Lyman limit systems. We therefore conclude that cold accretion flows exist and have already been detected in the form of high column density H I absorbers.

van de Voort, Freeke; Schaye, Joop; Altay, Gabriel; Theuns, Tom

2012-04-01

310

Spectroscopy with cold and ultra-cold neutrons  

E-print Network

We present two new types of spectroscopy methods for cold and ultra-cold neutrons. The first method, which uses the \\RB drift effect to disperse charged particles in a uniformly curved magnetic field, allows to study neutron $\\beta$-decay. We aim for a precision on the 10$^{-4}$ level. The second method that we refer to as gravity resonance spectroscopy (GRS) allows to test Newton's gravity law at short distances. At the level of precision we are able to provide constraints on any possible gravity-like interaction. In particular, limits on dark energy chameleon fields are improved by several orders of magnitude.

Hartmut Abele; Tobias Jenke; Gertrud Konrad

2014-12-16

311

Microstructured extremely thin absorber solar cells  

Microsoft Academic Search

In this paper we present the realization of extremely thin absorber (ETA) solar cells employing conductive glass substrates functionalized with TiO2 microstructures produced by embossing. Nanocrystalline or compact TiO2 films on Indium doped tin oxide (ITO) glass substrates were embossed by pressing a silicon stamp containing a ?m size raised grid structure into the TiO2 by use of a hydraulic

Matteo Biancardo; Frederik C. Krebs

2007-01-01

312

Design and Manufacture of Energy Absorbing Materials  

ScienceCinema

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.

Duoss, Eric

2014-05-30

313

Design and Manufacture of Energy Absorbing Materials  

SciTech Connect

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.

Duoss, Eric

2014-05-28

314

Tech Transfer Webinar: Energy Absorbing Materials  

SciTech Connect

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.

Duoss, Eric

2014-06-17

315

Dielectric studies of water absorbed in epoxies  

E-print Network

reorientation, ionic effects caused by ionizable groups, present in proteins, can result in charge diffusion to the condenser plates, giving rise to space charges. These space charges also contribute to the measured va"Ives of the dielectric constant e... DIELECTRIC STUDIES OF WATER ABSORBED IN EPOXIES A Thesis by HA QUOC PHAM Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE May 1987 Major Subject...

Pham, Ha Quoc

1987-01-01

316

BIOCHEMISTRY: An Absorbing Study of Cholesterol  

NSDL National Science Digital Library

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.

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

317

Crosslinked DADMAC polymers as cationic super absorbents  

Microsoft Academic Search

Loosely crosslinked cationic polyelectrolytes (polyquats) with super-water-sorption abilities are presented, for the first time. Hydrogels obtained by radically initiated copolymerization of N,N-diallyl, N,N-dimethyl ammonium chloride (DADMAC) with N-vinyl 2-pyrrolidone (NVP) in presence of N,N,N?,N?-tetraallyl piperazinium dichloride (TAP) as crosslinker showed reasonably high equilibrium swelling ratios, as high as those for poly(acrylic acid)-based super absorbents.The highest swelling ratios (up to 360)

Sinan Korpe; Bari? Erdo?an; Goknur Bayram; Serkan Ozgen; Yusuf Uludag; Niyazi Bicak

2009-01-01

318

Absorbable implants for open shoulder stabilization  

Microsoft Academic Search

Eighteen consecutive patients who had recurrent, unidirectional, post-traumatic shoulder instability were included. All these patients underwent surgery using an open Bankart technique involving absorbable suture anchors. The median age at the index operation was 27 (16–50) years. One subluxation and two re-dislocations occurred during the follow-up period of 90 (80–95) months. At the 90-month control, the Rowe and Constant scores

Lennart Magnusson; Lars Ejerhed; Lars Rostgård; Ninni Sernert; Jüri Kartus

2006-01-01

319

Lightweight Energy Absorbers for Blast Containers  

NASA Technical Reports Server (NTRS)

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.

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

2003-01-01

320

Tech Transfer Webinar: Energy Absorbing Materials  

ScienceCinema

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.

Duoss, Eric

2014-07-15

321

Shock wave absorber having a deformable liner  

DOEpatents

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.

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

1983-08-26

322

Heaving buoys, point absorbers and arrays.  

PubMed

Absorption of wave energy may be considered as a phenomenon of interference between incident and radiated waves generated by an oscillating object; a wave-energy converter (WEC) that displaces water. If a WEC is very small in comparison with one wavelength, it is classified as a point absorber (PA); otherwise, as a 'quasi-point absorber'. The latter may be a dipole-mode radiator, for instance an immersed body oscillating in the surge mode or pitch mode, while a PA is so small that it should preferably be a source-mode radiator, for instance a heaving semi-submerged buoy. The power take-off capacity, the WEC's maximum swept volume and preferably also its full physical volume should be reasonably matched to the wave climate. To discuss this matter, two different upper bounds for absorbed power are applied in a 'Budal diagram'. It appears that, for a single WEC unit, a power capacity of only about 0.3?MW matches well to a typical offshore wave climate, and the full physical volume has, unfortunately, to be significantly larger than the swept volume, unless phase control is used. An example of a phase-controlled PA is presented. For a sizeable wave-power plant, an array consisting of hundreds, or even thousands, of mass-produced WEC units is required. PMID:22184661

Falnes, Johannes; Hals, Jørgen

2012-01-28

323

Development of monofilar rotor hub vibration absorber  

NASA Technical Reports Server (NTRS)

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.

Duh, J.; Miao, W.

1983-01-01

324

Load limiting energy absorbing lightweight debris catcher  

NASA Technical Reports Server (NTRS)

In the representative embodiment of the invention disclosed, a load limiting, energy absorbing net is arranged to overlay a normally-covered vent opening in the rear bulkhead of the space orbiter vehicle. Spatially-disposed flexible retainer straps are extended from the net and respectively secured to bulkhead brackets spaced around the vent opening. The intermediate portions of the straps are doubled over and stitched together in a pattern enabling the doubled-over portions to progressively separate at a predicable load designed to be well below the tensile capability of the straps as the stitches are successively torn apart by the forces imposed on the retainer members whenever the cover plate is explosively separated from the bulkhead and propelled into the net. By arranging these stitches to be successively torn away at a load below the strap strength in response to forces acting on the retainers that are less than the combined strength of the retainers, this tearing action serves as a predictable compact energy absorber for safely halting the cover plate as the retainers are extended as the net is deployed. The invention further includes a block of an energy-absorbing material positioned in the net for receiving loose debris produced by the explosive release of the cover plate.

Kahn, Jon B. (inventor); Schneider, William C. (inventor)

1991-01-01

325

COSMIC DUST IN Mg II ABSORBERS  

SciTech Connect

Mg II absorbers induce reddening on background quasars. We measure this effect and infer the cosmic density of dust residing in these systems to be {Omega} Almost-Equal-To 2 Multiplication-Sign 10{sup -6}, in units of the critical density of the universe, which is comparable to the amount of dust found in galactic disks or about half the amount inferred to exist outside galaxies. We also estimate the neutral hydrogen abundance in Mg II clouds to be {Omega} Almost-Equal-To 1.5 Multiplication-Sign 10{sup -4}, which is approximately 5% of hydrogen in stars in galaxies. This implies a dust-to-gas mass ratio for Mg II clouds of about 1/100, which is similar to the value for normal galaxies. This would support the hypothesis of the outflow origin of Mg II clouds, which are intrinsically devoid of stars and hence have no sources of dust. Considerations of the dust abundance imply that the presence of Mg II absorbers around galaxies lasts effectively for a few Gyr. High-redshift absorbers allow us to measure the rest-frame extinction curve to 900 A, at which the absorption by the Lyman edge dominates over scattering by dust in the extinction opacity.

Menard, Brice [Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218 (United States); Fukugita, Masataka [Institute for the Physics and Mathematics of the Universe, University of Tokyo, Kashiwa 277-8583 (Japan)

2012-08-01

326

PT-symmetric laser-absorber  

E-print Network

In a recent work, Y.D. Chong et al. [Phys. Rev. Lett. {\\bf 105}, 053901 (2010)] proposed the idea of a coherent perfect absorber (CPA) as the time-reversed counterpart of a laser, in which a purely incoming radiation pattern is completely absorbed by a lossy medium. The optical medium that realizes CPA is obtained by reversing the gain with absorption, and thus it generally differs from the lasing medium. Here it is shown that a laser with an optical medium that satisfies the parity-time $(\\mathcal{PT})$ symmetry condition $\\epsilon(-\\mathbf{r})=\\epsilon^*(\\mathbf{r})$ for the dielectric constant behaves simultaneously as a laser oscillator (i.e. it can emit outgoing coherent waves) and as a CPA (i.e. it can fully absorb incoming coherent waves with appropriate amplitudes and phases). Such a device can be thus referred to as a $\\mathcal{PT}$-symmetric CPA-laser. The general amplification/absorption features of the $\\mathcal{PT}$ CPA-laser below lasing threshold driven by two fields are determined.

Stefano Longhi

2010-08-31

327

COLD-SAT dynamic model  

NASA Technical Reports Server (NTRS)

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.

Adams, Neil S.; Bollenbacher, Gary

1992-01-01

328

Cold atoms by kinematic cooling  

SciTech Connect

We report the preparation and observation of translationally cold atoms using kinematic cooling. In these experiments, krypton atoms are cooled to subkelvin temperatures by elastic collisions in crossed atomic beams. Two independent velocity measurements indicate an upper-bound mean velocity of 13 m/s (E{sub trans}/k=850 mK) and are consistent with a much lower mean velocity of 4 m/s (E{sub trans}/k=80 mK) (k is Boltzmann's constant). The density of the cold atoms is measured to be 10{sup 9} atoms/cm{sup 3}. Scattering calculations and diffusion models support these velocity and density measurements. The results demonstrate that cold, dense samples of ground-state atoms and molecules can be prepared by elastic collisions between identical collision partners.

Kay, Jeffrey J.; Strecker, Kevin E.; Chandler, David W. [Sandia National Laboratories, Livermore, California 94550 (United States); Klos, Jacek; Alexander, Millard H. [University of Maryland, College Park, Maryland 20742 (United States)

2010-09-15

329

Compressed absorbing boundary conditions for the Helmholtz equation  

E-print Network

Absorbing layers are sometimes required to be impractically thick in order to offer an accurate approximation of an absorbing boundary condition for the Helmholtz equation in a heterogeneous medium. It is always possible ...

Bélanger-Rioux, Rosalie

2014-01-01

330

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

Code of Federal Regulations, 2010 CFR

...FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES OPHTHALMIC DEVICES Prosthetic Devices § 886.3300 Absorbable implant (scleral buckling method). (a) Identification. An absorbable...

2010-04-01

331

21 CFR 880.5300 - Medical absorbent fiber.  

Code of Federal Regulations, 2014 CFR

...Devices § 880.5300 Medical absorbent fiber. (a) Identification. A medical absorbent fiber is a device intended for medical purposes that is made from cotton or synthetic fiber in the shape of a ball or a pad...

2014-04-01

332

21 CFR 880.5300 - Medical absorbent fiber.  

Code of Federal Regulations, 2012 CFR

...Devices § 880.5300 Medical absorbent fiber. (a) Identification. A medical absorbent fiber is a device intended for medical purposes that is made from cotton or synthetic fiber in the shape of a ball or a pad...

2012-04-01

333

21 CFR 880.5300 - Medical absorbent fiber.  

Code of Federal Regulations, 2013 CFR

...Devices § 880.5300 Medical absorbent fiber. (a) Identification. A medical absorbent fiber is a device intended for medical purposes that is made from cotton or synthetic fiber in the shape of a ball or a pad...

2013-04-01

334

Modeling the Effect of Polychromatic Light in Quantitative Absorbance Spectroscopy  

ERIC Educational Resources Information Center

Laboratory experiment is conducted to give the students practical experience with the principles of electronic absorbance spectroscopy. This straightforward approach creates a powerful tool for exploring many of the aspects of quantitative absorbance spectroscopy.

Smith, Rachel; Cantrell, Kevin

2007-01-01

335

An Energy Absorber for the International Space Station  

NASA Technical Reports Server (NTRS)

The energy absorber described herein is similar in size and shape to an automotive shock absorber, requiring a constant, high load to compress over the stroke, and self-resetting with a small load. The differences in these loads over the stroke represent the energy absorbed by the device, which is dissipated as friction. This paper describes the evolution of the energy absorber, presents the results of testing performed, and shows the sensitivity of this device to several key design variables.

Wilkes, Bob; Laurence, Lora

2000-01-01

336

Dynamic testing of airplane shock-absorbing struts  

NASA Technical Reports Server (NTRS)

Measurement of perpendicular impacts of a landing gear with different shock-absorbing struts against the drum testing stand. Tests were made with pneumatic shock absorbers having various degrees of damping, liquid shock absorbers, steel-spring shock absorbers and rigid struts. Falling tests and rolling tests. Maximum impact and gradual reduction of the impacts in number and time in the falling tests. Maximum impact and number of weaker impacts in rolling tests.

Langer, P; Thome, W

1932-01-01

337

Method for absorbing an ion from a fluid  

DOEpatents

A method for absorbing an ion from a fluid by using dispersing an organic acid into an anion surfactant solution, mixing in a divalent-metal containing compound and a trivalent-metal containing compound and calcining the resulting solid layered double hydroxide product to form an absorbent material and then contacting the absorbent material with an aqueous solution of cations or anions to be absorbed.

Gao, Huizhen (Carlsbad, NM); Wang, Yifeng (Albuquerque, NM); Bryan, Charles R. (Albuquerque, NM)

2007-07-03

338

Smooth maps from clumpy data  

E-print Network

We study an estimator for smoothing irregularly sampled data into a smooth map. The estimator has been widely used in astronomy, owing to its low level of noise; it involves a weight function -- or smoothing kernel -- w(\\theta). We show that this estimator is not unbiased, in the sense that the expectation value of the smoothed map is not the underlying process convolved with $w$, but a convolution with a modified kernel w_eff(\\theta). We show how to calculate w_eff for a given kernel w and investigate its properties. In particular, it is found that (1) w_eff is normalized, (2) has a shape `similar' to the original kernel w, (3) converges to w in the limit of high number density of data points, and (4) reduces to a top-hat filter in the limit of very small number density of data points. Hence, although the estimator is biased, the bias is well understood analytically, and since w_eff has all the desired properties of a smoothing kernel, the estimator is in fact very useful. We present explicit examples for several filter functions which are commonly used, and provide a series expression valid in the limit of large density of data points.

Marco Lombardi; Peter Schneider

2001-04-07

339

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

NASA Astrophysics Data System (ADS)

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.

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

2007-02-01

340

14 CFR 27.475 - Tires and shock absorbers.  

Code of Federal Regulations, 2011 CFR

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

2011-01-01

341

14 CFR 29.475 - Tires and shock absorbers.  

Code of Federal Regulations, 2012 CFR

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

2012-01-01

342

14 CFR 29.475 - Tires and shock absorbers.  

Code of Federal Regulations, 2013 CFR

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

2013-01-01

343

14 CFR 29.475 - Tires and shock absorbers.  

Code of Federal Regulations, 2010 CFR

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

2010-01-01

344

Testing Shock Absorbers: Towards a Faster Parallelizable Algorithm  

E-print Network

Testing Shock Absorbers: Towards a Faster Parallelizable Algorithm Christian Servin Computational@miners.utep.edu Abstract--Cars are equipped with shock absorbers, which are designed to smooth out the shocks on the road. In practice, there is a need to test them. To test the shock absorbers, we need to estimate the values

Ward, Karen

345

14 CFR 27.475 - Tires and shock absorbers.  

Code of Federal Regulations, 2012 CFR

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

2012-01-01

346

14 CFR 27.475 - Tires and shock absorbers.  

Code of Federal Regulations, 2014 CFR

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

2014-01-01

347

14 CFR 27.475 - Tires and shock absorbers.  

Code of Federal Regulations, 2010 CFR

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

2010-01-01

348

14 CFR 29.475 - Tires and shock absorbers.  

Code of Federal Regulations, 2011 CFR

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

2011-01-01

349

14 CFR 29.475 - Tires and shock absorbers.  

Code of Federal Regulations, 2014 CFR

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

2014-01-01

350

14 CFR 27.475 - Tires and shock absorbers.  

Code of Federal Regulations, 2013 CFR

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

2013-01-01

351

Infrared temperature measurements on solar trough absorber tubes  

Microsoft Academic Search

The temperature distribution on solar trough absorber tubes determines thermal losses and hotspots can lead to material stress and limit absorber tube lifetime. The concentrated solar radiation, however, makes it difficult to determine the temperature on solar absorbers. Temperature sensors that require contact to the measurement object are not appropriate and even pyrometry fails, when external light sources interfere. Only

Markus Pfänder; Eckhard Lüpfert; Paul Pistor

2007-01-01

352

Bellows joint absorbs torsional deflections in duct system  

NASA Technical Reports Server (NTRS)

Long, thin-walled bellows compressed into a short length absorbs the same amount of torsional deflection as the same tube in full length condition and saves in cost, complexity and space. This bellows has lower torsional spring rate to absorb the bulk of the duct assembly tortional deflections, leaving the other bellows free to absorb axial and angular deflections.

Daniels, C. M.

1966-01-01

353

Vibroacoustics of thin micro-perforated sound absorbers , T. Bravob  

E-print Network

Vibroacoustics of thin micro-perforated sound absorbers C. Maurya , T. Bravob and C. Pinhedea constitute compact sound absorbing resonators, mostly efficient in the mid-frequency range, and that may the sound absorbing model initially proposed by Maa for a rigid MPP [1]. The aim of this work

Boyer, Edmond

354

Optimization of electric shunt resonant circuits for electroacoustic absorbers  

E-print Network

as an absorber/reflector of sound, and the electric terminals of which are connected to a dedicated electric load electroacoustic absorbers. 1 Introduction Turning an electrodynamic loudspeaker into a sound ab- sorber can as a 1 degree of freedom mechanical resonator, thus capable of absorbing some sound energy

Paris-Sud XI, Université de

355

Phenolic laminate solar absorber panel and method of making  

Microsoft Academic Search

A solar flat plate absorber panel is molded from a laminate consisting of a suitable web material impregnated with a thermosetting phenolic resin. The absorber plate is pressure formed from superimposed layers of material and mold-cured to produce a unitary structure having a first or solar radiation absorbing surface on one side and an integral closed hollow lattice work of

Severson

1979-01-01

356

Selective absorber on glass and method for its production  

Microsoft Academic Search

An improved selective absorber on a glass substrate having high solar absorption and low infrared emission. The selective absorber on a glass substrate includes an electrically conducting layer of silver metal having a thickness on the order of 0.1 microns, and an absorbing layer of either black nickel or, alternatively, a layer of oxidized iron over a layer of nickel

1980-01-01

357

A resonant point absorber of ocean-wave power  

Microsoft Academic Search

A system for absorbing and utilizing the energy carried by ocean waves is discussed. The 'point absorber' considered is a system in which the horizontal extent is much smaller than one wavelength. The point absorber is optimized for efficient energy conversion. The resonant characteristic frequency of the system is at all times tuned to the characteristic frequency of the wave.

K. Budar; J. Falnes

1975-01-01

358

Avionics Box Cold Plate Damage Prevention  

NASA Technical Reports Server (NTRS)

Problem Introduction: 1. Prevent Cold Plate Damage in Space Shuttle. 1a. The number of cold plate problems had increased from an average of 16.5 per/year between 1990 through 2000, to an average of 39.6 per year between 2001through 2005. 1b. Each complete set of 80 cold plates cost approximately $29 million, an average of $362,500 per cold plate. 1c It takes four months to produce a single cold plate. 2. Prevent Cold Plate Damage in Future Space Vehicles.

Stambolian, Damon B.; Larchar, Steven W.; Henderson, Gena; Tran, Donald; Barth, Tim

2012-01-01

359

The cold war's “soft” recruits  

Microsoft Academic Search

When forecasts of swift victory give way to pessimism as wars inevitably become prolonged, nations often search within their own borders for the reasons that explain the possibility of defeat. It was a revealing irony of the Cold War stalemate that the U.S. worried that democratic individualism and a free enterprise economy might prove to be the nation's most crippling

Marc Richards

1998-01-01

360

Hot, Cold, Fresh and Salty  

NSDL National Science Digital Library

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.

Jerry Roth

361

The Cold Blooded Killer: Hypothermia.  

ERIC Educational Resources Information Center

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…

Keller, Rosanne

362

Cold Controlled Chemistry Roman Krems  

E-print Network

· Possible applications of cold controlled chemistry #12; #¢¡ ©£¡ ! # %¢ ¥¤6#¢¡§¦ # ¤¨¤§! # ¤§¦ Centrifugal processes remains a significant challenge..." Paul Brumer, DAMOP 2007, Bulletin of the APS #12;Thermal gas is difficult to control #12;Low temperature gas under external fieldE #12;E BLow temperature gas

Krems, Roman

363

Cold plasma decontamination of foods  

Technology Transfer Automated Retrieval System (TEKTRAN)

Cold plasma is a novel nonthermal food processing technology which uses energetic, reactive gases to inactivate contaminating microbes on meats, poultry and fruits and vegetables. This flexible sanitizing method uses electricity and a carrier gas such as air, oxygen, nitrogen or helium; antimicrobi...

364

Interface Model of Cold Fusion  

Microsoft Academic Search

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

Talbot A. Chubb

365

Piston-rotaxanes as molecular shock absorbers.  

PubMed

We describe the thermomechanical response of a new molecular system that behaves as a shock absorber. The system consists of a rodlike rotaxane connected to a piston and tethered to a surface. The response of this system is dominated by the translational entropy of the rotaxane rings and can be calculated exactly. The force laws are contrasted with those for a rigid rod and a polymer. In some cases, the rotaxanes undergo a sudden transition to a tilted state when compressed. These piston-rotaxanes provide a potential motif for the design of a new class of materials with a novel thermomechanical response. PMID:20158174

Sevick, E M; Williams, D R M

2010-04-20

366

Notes 10. The dynamic vibration absorber  

E-print Network

? 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...

San Andres, Luis

2008-01-01

367

An electromechanical low frequency panel sound absorber.  

PubMed

The sound absorbing properties of a thin micro-perforated plate (MPP) coated with piezoelectric material with shunt damping technology is investigated. First a theoretical model is presented to predict the sound absorption coefficients of a thin plate attached with a piezoelectric patch and electrical circuits. Then the model is extended to analyze the sound absorption for a thin plate with micro perforations and piezoelectric material. Measurements are also carried out in an impedance tube and found to be in good agreements with the theoretical model. The sound absorption of the constructions can be much improved by tuning the electrical circuits. PMID:20707433

Chang, Daoqing; Liu, Bilong; Li, Xiaodong

2010-08-01

368

Optical Pulsing in an Absorbing Liquid  

NASA Astrophysics Data System (ADS)

A continuous-wave laser can be converted into a series of repetitive pulses by focusing the laser beam into an absorbing liquid (e.g. nigrosine dissolved in a solvent), where the mechanism responsible for the pulses is the scattering of light off of photo-generated bubbles. The dependence of the pulsation frequency on the solvent, power, and cell thickness will be shown. The authors would like to acknowledge the contributions made by Prof. Daniel Lathrop (University of Maryland, Department of Physics) at the APS March 2002 meeting.

Barnes, Jacob; Evans, Dean; Guha, Shekhar

2003-03-01

369

Acoustical model of a Shoddy fibre absorber  

NASA Astrophysics Data System (ADS)

Shoddy fibres or "Shoddies" are a mixture of post-consumer and post-industrial fibres diverted from textile waste streams and recycled into their raw fibre form. They have found widespread use as a raw material for manufacturing sound absorbers that include, but are not limited to: automotive, architectural and home appliance applications. The purpose of this project is to develop a simple acoustic model to describe the acoustic behaviour of sound absorbers composed primarily of Shoddy fibres. The model requires knowledge of the material's bulk density only. To date, these materials have not been the focus of much published research and acoustical designers must rely on models that were developed for other materials or are overly complex. For modelling purposes, an equivalent fluid approach is chosen to balance complexity and accuracy. In deriving the proposed model, several popular equivalent fluid models are selected and the required input parameters for each model identified. The models are: the model of Delaney and Bazley, two models by Miki, the model of Johnson in conjunction with the model of Champoux and Allard and the model of Johnson in conjunction with the model of Lafarge. Characterization testing is carried out on sets of Shoddy absorbers produced using three different manufacturing methods. The measured properties are open porosity, tortuosity, airflow resistivity, the viscous and thermal characteristic lengths and the static thermal permeability. Empirical relationships between model parameters and bulk density are then derived and used to populate the selected models. This yields several 'simplified' models with bulk density as the only parameter. The most accurate model is then selected by comparing each model's prediction to the results of normal incidence sound absorption tests. The model of Johnson-Lafarge populated with the empirical relations is the most accurate model over the range of frequencies considered (approx. 300 Hz - 4000 Hz) Characterization testing yields specific values for intrinsic material parameters that allow for comparison to other porous materials. Individual parameter relations allow users to substitute measured or theoretical values as needed. A new empirical acoustical model is proposed to describe the behaviour of Shoddy-based fibre absorbers. The model requires knowledge of the bulk density only. This parameter is easily measured making application of the model elementary. Mots-clés : Shoddy, porous, fibre, recycled, absorption, model, acoustic.

Manning, John Peter

370

Heat Transfer Performance of Absorber of Absorption Refrigerating Machine  

NASA Astrophysics Data System (ADS)

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.

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

371

Cold denaturation of monoclonal antibodies  

PubMed Central

The susceptibility of monoclonal antibodies (mAbs) to undergo cold denaturation remains unexplored. In this study, the phenomenon of cold denaturation was investigated for a mAb, mAb1, through thermodynamic and spectroscopic analyses. tryptophan fluorescence and circular dichroism (CD) spectra were recorded for the guanidine hydrochloride (GuHCl)-induced unfolding of mAb1 at pH 6.3 at temperatures ranging from ?5 to 50°C. A three-state unfolding model incorporating the linear extrapolation method was fit to the fluorescence data to obtain an apparent free energy of unfolding, ?Gu, at each temperature. CD studies revealed that mAb1 exhibited polyproline II helical structure at low temperatures and at high GuHCl concentrations. the Gibbs-Helmholtz expression fit to the ?Gu versus temperature data from fluorescence gave a ?Cp of 8.0 kcal mol?1 K?1, a maximum apparent stability of 23.7 kcal mol?1 at 18°C, and an apparent cold denaturation temperature (TCD) of ?23°C. ?Gu values for another mAb (mAb2) with a similar framework exhibited less stability at low temperatures, suggesting a depressed protein stability curve and a higher relative TCD. Direct experimental evidence of the susceptibility of mAb1 and mAb2 to undergo cold denaturation in the absence of denaturant was confirmed at pH 2.5. thus, mAbs have a potential to undergo cold denaturation at storage temperatures near ?20°C (pH 6.3), and this potential needs to be evaluated independently for individual mAbs. PMID:20093856

Lazar, Kristi L; Patapoff, Thomas W

2010-01-01

372

Cold-Weather Sports and Your Family  

MedlinePLUS

... the weather turns frosty. Beating the Cold-Weather Blahs Once a chill is in the air, our ... more sedentary can lead to the "cold-weather blahs." Kids might feel more tired, lethargic, or even ...

373

Vitamin C and the Common Cold Revisited.  

ERIC Educational Resources Information Center

Various studies indicate that Vitamin C does not prevent or cure a cold, but it may ameliorate symptoms in some individuals. The development of a balanced life-style is more effective towards cold prevention. (DF)

Travis, H. Richard

1984-01-01

374

Common cold - how to treat at home  

MedlinePLUS

... Antibiotics are almost never needed to treat a common cold. Acetaminophen (Tylenol) and ibuprofen (Advil, Motrin) help lower ... Many home remedies are popular treatments for the common cold. These include vitamin C, zinc supplements, and Echinacea. ...

375

Helium Find Thaws the Cold Fusion Trail.  

ERIC Educational Resources Information Center

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)

Pennisi, E.

1991-01-01

376

21 CFR 890.5700 - Cold pack.  

Code of Federal Regulations, 2014 CFR

...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...

2014-04-01

377

21 CFR 890.5700 - Cold pack.  

Code of Federal Regulations, 2012 CFR

...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...

2012-04-01

378

Shocks and cold fronts in galaxy clusters  

E-print Network

Table of contents (abridged): COLD FRONTS Origin and evolution of merger cold fronts Cold fronts in cluster cool cores . . . Simulations of gas sloshing. Origin of density discontinuity. . . . Effect of sloshing on cluster mass estimates and cooling flows. Zoology of cold fronts COLD FRONTS AS EXPERIMENTAL TOOL Velocities of gas flows Thermal conduction and diffusion across cold fronts Stability of cold fronts . . . Rayleigh-Taylor instability. Kelvin-Helmholtz instability. Possible future measurements using cold fronts . . . Plasma depletion layer and magnetic field. Effective viscosity of ICM. SHOCK FRONTS AS EXPERIMENTAL TOOL Cluster merger shocks Mach number determination Front width Mach cone and reverse shock? Test of electron-ion equilibrium . . . Comparison with other astrophysical plasmas Shocks and cluster cosmic ray population . . . Shock acceleration. Compression of fossil electrons. . . . Yet another method to measure intracluster magnetic field.

Maxim Markevitch; Alexey Vikhlinin

2007-04-24

379

Absorber Alignment Measurement Tool for Solar Parabolic Trough Collectors: Preprint  

SciTech Connect

As we pursue efforts to lower the capital and installation costs of parabolic trough solar collectors, it is essential to maintain high optical performance. While there are many optical tools available to measure the reflector slope errors of parabolic trough solar collectors, there are few tools to measure the absorber alignment. A new method is presented here to measure the absorber alignment in two dimensions to within 0.5 cm. The absorber alignment is measured using a digital camera and four photogrammetric targets. Physical contact with the receiver absorber or glass is not necessary. The alignment of the absorber is measured along its full length so that sagging of the absorber can be quantified with this technique. The resulting absorber alignment measurement provides critical information required to accurately determine the intercept factor of a collector.

Stynes, J. K.; Ihas, B.

2012-04-01

380

Composite neutron absorbing coatings for nuclear criticality control  

DOEpatents

Thermal neutron absorbing composite coating materials and methods of applying such coating materials to spent nuclear fuel storage systems are provided. A composite neutron absorbing coating applied to a substrate surface includes a neutron absorbing layer overlying at least a portion of the substrate surface, and a corrosion resistant top coat layer overlying at least a portion of the neutron absorbing layer. An optional bond coat layer can be formed on the substrate surface prior to forming the neutron absorbing layer. The neutron absorbing layer can include a neutron absorbing material, such as gadolinium oxide or gadolinium phosphate, dispersed in a metal alloy matrix. The coating layers may be formed by a plasma spray process or a high velocity oxygen fuel process.

Wright, Richard N.; Swank, W. David; Mizia, Ronald E.

2005-07-19

381

Determination of decay coefficients for combustors with acoustic absorbers  

NASA Technical Reports Server (NTRS)

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.

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

1972-01-01

382

Container and method for absorbing and reducing hydrogen concentration  

DOEpatents

A method for absorbing hydrogen from an enclosed environment comprising providing a vessel; providing a hydrogen storage composition in communication with a vessel, the hydrogen storage composition further comprising a matrix defining a pore size which permits the passage of hydrogen gas while blocking the passage of gaseous poisons; placing a material within the vessel, the material evolving hydrogen gas; sealing the vessel; and absorbing the hydrogen gas released into the vessel by the hydrogen storage composition. A container for absorbing evolved hydrogen gas comprising: a vessel having an interior and adapted for receiving materials which release hydrogen gas; a hydrogen absorbing composition in communication with the interior, the composition defining a matrix surrounding a hydrogen absorber, the matrix permitting the passage of hydrogen gas while excluding gaseous poisons; wherein, when the vessel is sealed, hydrogen gas, which is released into the vessel interior, is absorbed by the hydrogen absorbing composition.

Wicks, George G. (Aiken, SC); Lee, Myung W. (North Augusta, SC); Heung, Leung K. (Aiken, SC)

2001-01-01

383

The cold equation of state of tantalum  

SciTech Connect

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.

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

384

Wave based optimization of distributed vibration absorbers  

NASA Astrophysics Data System (ADS)

The concept of distributed vibration absorbers or DVAs has been investigated in recent years as a method of vibration control and sound radiation control for large flexible structures. These devices are comprised of a distributed compliant layer with a distributed mass layer. When such a device is placed onto a structure it forms a sandwich panel configuration with a very soft core. With this configuration the main effect of the DVA is to create forces normal to the surface of the structure and can be used at low frequencies to either add damping, where constrain layer damper treatments are not very effective, or to pin the structure over a narrow frequency bandwidth (i.e., large input impedance/vibration absorber approach). This paper analyses the behavior of these devices using a wave based approach and finds an optimal damping level for the control of broadband disturbances in panels. The optimal design is calculated by solving the differential equations for waves propagating in coupled plates. It is shown that the optimal damping calculated using the infinite case acts as a good ``rule of thumb'' for designing DVAs to control the vibration of finite panels. This is bourn out in both numerical simulations and experiments.

Johnson, Marty; Batton, Brad

2005-09-01

385

Wave energy extraction by coupled resonant absorbers.  

PubMed

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

Evans, D V; Porter, R

2012-01-28

386

Erbium concentration dependent absorbance in tellurite glass  

NASA Astrophysics Data System (ADS)

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 Er3+ 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 4F7/2, 2H11/2, 4F9/2, 4I9/2, 2H11/2 and 4I13/2, respectively. The results are analyzed by means of optical band gap Eg and Urbach energy Eu. 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 Er2O3 concentration from 0 to 1.5 mol%. The excellent absorbance of the prepared tellurite glasses makes them suitable for fabricating solid state lasers.

Sazali, E. S.; Rohani, M. S.; Sahar, M. R.; Arifin, R.; Ghoshal, S. K.; Hamzah, K.

2014-09-01

387

QCSEE fan exhaust bulk absorber treatment evaluation  

NASA Technical Reports Server (NTRS)

The purpose of the experimental program reported herein was to evaluate the acoustic suppression capability of bulk absorber material designed for use in the fan exhaust duct walls of the QCSEE UTW (under-the-wing) engine and to compare it with other means of acoustic suppression. The paper includes comparison of the acoustic suppression to the original design for the QCSEE UTW engine fan duct which consisted of phased SDOF (single-degree-of-freedom) wall treatment and a splitter and also with the splitter removed. The method of approach consisted of mounting the UTW engine on the test stand of the Lewis Engine Noise Facility with an appropriate array of far-field microphones in order to measure the acoustic levels of the various configurations. 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.

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

1980-01-01

388

Erbium concentration dependent absorbance in tellurite glass  

SciTech Connect

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.

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

389

Metamaterial perfect absorber based hot electron photodetection.  

PubMed

While the nonradiative decay of surface plasmons was once thought to be only a parasitic process that limits the performance of plasmonic devices, it has recently been shown that it can be harnessed in the form of hot electrons for use in photocatalysis, photovoltaics, and photodetectors. Unfortunately, the quantum efficiency of hot electron devices remains low due to poor electron injection and in some cases low optical absorption. Here, we demonstrate how metamaterial perfect absorbers can be used to achieve near-unity optical absorption using ultrathin plasmonic nanostructures with thicknesses of 15 nm, smaller than the hot electron diffusion length. By integrating the metamaterial with a silicon substrate, we experimentally demonstrate a broadband and omnidirectional hot electron photodetector with a photoresponsivity that is among the highest yet reported. We also show how the spectral bandwidth and polarization-sensitivity can be manipulated through engineering the geometry of the metamaterial unit cell. These perfect absorber photodetectors could open a pathway for enhancing hot electron based photovoltaic, sensing, and photocatalysis systems. PMID:24837991

Li, Wei; Valentine, Jason

2014-06-11

390

Impedance theory of sound scattering and absorption: A constrained best absorber and the efficiency bounds of passive scatterers and absorbers  

NASA Astrophysics Data System (ADS)

A constrained best absorber is defined as a body that absorbs the maximum incident sound power among all of the passive bodies of the same geometry under the condition that the sound power scattered by it is fixed. By solving a variational problem, the surface impedances of the constrained best absorber are determined and the efficiency bounds of passive scatterers and absorbers are found. The range of all the allowable values of the absorption and scattering powers of an arbitrary passive body is represented graphically. For the boundaries of this range, analytical formulas are derived. Some of the properties of constrained best absorbers are considered, and illustrative examples are presented.

Bobrovnitski?, Yu. I.

2007-02-01

391

Integrating non-planar metamaterials with magnetic absorbing materials to yield ultra-broadband microwave hybrid absorbers  

NASA Astrophysics Data System (ADS)

Broadening the bandwidth of electromagnetic wave absorbers has greatly challenged material scientists. Here, we propose a two-layer hybrid absorber consisting of a non-planar metamaterial (MM) and a magnetic microwave absorbing material (MAM). The non-planar MM using magnetic MAMs instead of dielectric substrates shows good low frequency absorption and low reflection across a broad spectrum. Benefiting from this and the high frequency strong absorption of the MAM layer, the lightweight hybrid absorber exhibits 90% absorptivity over the whole 2-18 GHz range. Our result reveals a promising and flexible method to greatly extend or control the absorption bandwidth of absorbers.

Li, Wei; Wu, Tianlong; Wang, Wei; Guan, Jianguo; Zhai, Pengcheng

2014-01-01

392

Cold Fusion Has Now Come Out of the Cold  

Microsoft Academic Search

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.

Edmund Storms

2003-01-01

393

IEA HPP Annex 41 Cold Climate Heat  

E-print Network

various design options for cold climate heat pump applications on common basis #12;Meeting Dates#12;IEA HPP Annex 41 ­ Cold Climate Heat Pumps: Improving Low Ambient Temperature Performance ­ Cold Climate Heat Pumps Improving low ambient temperature performance of air-source heat pumps

Oak Ridge National Laboratory

394

Vitamin C and the common cold  

Microsoft Academic Search

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

Harri Hemilä

1992-01-01

395

Cold vs. Flu Know the Difference  

E-print Network

Cold vs. Flu Know the Difference Symptoms Cold Flu Fever Rare Usual ­ can be 100 to 102or higher can help prevent the spread of colds or flu F � KEEP YOUR HANDS CLEAN ­ Wash with soap and water. � STAY HOME WHEN SICK � GET VACCINATED FOR FLU Getting a flu shot or the nasal spray every year

Burke, Peter

396

Cold tolerance encoded in one SNP.  

PubMed

Cold tolerance fundamentally affects world crop harvest. Ma et al. now identify a single-nucleotide polymorphism in a gene called COLD1 that confers cold tolerance in japonica rice. This study reveals important insights into agronomical traits that are essential for human nutrition. PMID:25768901

Manishankar, Prabha; Kudla, Jörg

2015-03-12

397

Psychrophilic enzymes: hot topics in cold adaptation  

Microsoft Academic Search

More than three-quarters of the Earth's surface is occupied by cold ecosystems, including the ocean depths, and polar and alpine regions. These permanently cold environments have been successfully colonized by a class of extremophilic microorganisms that are known as psychrophiles (which literally means cold-loving). The ability to thrive at temperatures that are close to, or below, the freezing point of

Charles Gerday; Georges Feller

2003-01-01

398

Vernalizing cold is registered digitally at FLC  

PubMed Central

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

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

2015-01-01

399

THE COMMON COLD—FACT AND FANCY  

PubMed Central

A great deal of folklore, superstition and emotional reaction is attached to the common cold, but established objective information is quite limited. The evidence concerning etiology, epidemiology, physiology, prevention and treatment of the common cold is briefly summarized and critically evaluated. There is disappointing lack of real progress in any of these aspects of the common cold problem. PMID:14778003

Jawetz, E.; Talbot, J. C.

1950-01-01

400

Cold dark matter heats up.  

PubMed

A principal discovery in modern cosmology is that standard model particles comprise only 5 per cent of the mass-energy budget of the Universe. In the ?CDM paradigm, the remaining 95 per cent consists of dark energy (?) and cold dark matter. ?CDM is being challenged by its apparent inability to explain the low-density 'cores' of dark matter measured at the centre of galaxies, where centrally concentrated high-density 'cusps' were predicted. But before drawing conclusions, it is necessary to include the effect of gas and stars, historically seen as passive components of galaxies. We now understand that these can inject heat energy into the cold dark matter through a coupling based on rapid gravitational potential fluctuations, explaining the observed low central densities. PMID:24522596

Pontzen, Andrew; Governato, Fabio

2014-02-13

401

Ultra-cold molecule production.  

SciTech Connect

The production of Ultra-cold molecules is a goal of many laboratories through out the world. Here we are pursuing a unique technique that utilizes the kinematics of atomic and molecular collisions to achieve the goal of producing substantial numbers of sub Kelvin molecules confined in a trap. Here a trap is defined as an apparatus that spatially localizes, in a known location in the laboratory, a sample of molecules whose temperature is below one degree absolute Kelvin. Further, the storage time for the molecules must be sufficient to measure and possibly further cool the molecules. We utilize a technique unique to Sandia to form cold molecules from near mass degenerate collisions between atoms and molecules. This report describes the progress we have made using this novel technique and the further progress towards trapping molecules we have cooled.

Ramirez-Serrano, Jamie; Chandler, David W.; Strecker, Kevin; Rahn, Larry A.

2005-12-01

402

Simulations of Cold Electroweak Baryogenesis  

E-print Network

Cold Electroweak Baryogenesis is an attempt to explain the cosmological baryon asymmetry using only a minimal extension of the Standard Model. The relevant processes take place out of thermal equilibrium and are non-perturbative, and so must be studied using full, real-time lattice simulations. We present new results on the dependence on CP-violation and the Higgs-to-W-mass ratio

Anders Tranberg; Jan Smit

2005-10-27

403

Status of cold fusion (2010)  

Microsoft Academic Search

The phenomenon called cold fusion has been studied for the last 21 years since its discovery by Profs. Fleischmann and Pons\\u000a in 1989. The discovery was met with considerable skepticism, but supporting evidence has accumulated, plausible theories have\\u000a been suggested, and research is continuing in at least eight countries. This paper provides a brief overview of the major\\u000a discoveries and some

Edmund Storms

2010-01-01

404

Cold cathode vacuum discharge tube  

DOEpatents

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.

Boettcher, Gordon E. (Albuquerque, NM)

1998-01-01

405

Acclimatization to cold in humans  

NASA Technical Reports Server (NTRS)

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.

Kaciuba-Uscilko, Hanna; Greenleaf, John E.

1989-01-01

406

Tally of Cold Fusion Papers  

Microsoft Academic Search

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

Jed Rothwell

2009-01-01

407

Insulation grapes cold winter effect  

NASA Astrophysics Data System (ADS)

Purposes: The study of several insulation in cold conditions in Xinjiang Gobi Grape safe winter effect. Procedures and Method: The use of real-time U-plate thermometer to measure temperature changes recorded instrument to study the severe winter conditions, several insulation effect at different depths of grape root, and the cold resistance of winter grape roots at different depths variation; research in the coming year the spring and summer seasons, blooming the results of several insulation grape growth and development. Results: Several insulation Gobi Grape security winter better, surface temperature is largely improved compared with the control. The D900 collodions+ enhanced membrane to improve the 11.69°C, non-woven + buried improve the 10.09°C. D900 no glue cotton + enhanced membrane covering the grape surface <=-5°C continuous days of relatively non-woven + buried reduce eight days underground 30cm, a decrease of 5 days. D900 no glue cotton + Enhanced membrane covering the minimum grape underground temperature than the non-woven+ buried there is a significant improvement of the surface temperature has increased 1.57°C, the underground at 30 cm temperature has increased 1.08°C, 60cm, underground buried than the processing temperature has increased 1.54°C, the insulation effect. Conclusions: Xinjiang cold conditions, the D900 without glue cotton+ film way cover the grapes can live through the winter, is to protect the winter safety of the grapes and grape production.

Guo, Shao-jie; Li, Ming; Ying, Liang-fu

408

Mars: Always Cold, Sometimes Wet?  

NASA Technical Reports Server (NTRS)

A synthesis of a diverse suite of observations of H2O-related landforms that are possible Mars analogs from terrestrial polar regions (Devon Island in the Arctic; the Dry Valleys of Antarctica) put into question any requirement for extended episode(s) of warm and wet climate in Mars past. Geologically transient episodes of localized H2O cycling, forced by exogenic impacts, enhanced endogenic heat flow, and/or orbit-driven short-term local environmental change under an otherwise cold, low pressure (=10(exp 2) mbar) global climate, may be sufficient to account for the martian surface's exposed record of aqueous activity. A Mars that was only sometimes locally warm and wet while remaining climatically cold throughout its history is consistent with results (difficulties) encountered in modeling efforts attempting to support warm martian climate hypotheses. Possible analogs from terrestrial cold climate regions for the recent gully features on Mars also illustrate how transient localized aqueous activity might, under specific circumstances, also occur on Mars under the present frigid global climatic regime.

Lee, Pascal; McKay, Christoper P.

2003-01-01

409

Quantum criticality in cold atoms  

NASA Astrophysics Data System (ADS)

We construct a general set of techniques to extract universal quantum critical behavior from cold atoms experiments. Quantum criticality --- the finite temperature behavior of systems near quantum phase transitions --- is a cornerstone of modern solid state physics, providing examples of non-quasiparticle excitations and interpretations of a wide variety of strongly correlated materials. Since often even the simplest models' behavior is unknown, cold atoms can dramatically improve our understanding. Yet the phenomenology of the quantum critical regime has received little attention, despite the fact that many ongoing experiments are in this regime. We show that quantum critical phenomena are robust in cold atoms: they persist despite the small number of atoms and the inhomogeneity of the harmonic traps. We construct novel analysis methods to observe quantum criticality in these system. We demonstrate the utility of these methods by examining exactly solvable models and quantum Monte Carlo calculations. Additionally, we make first comparisons with experiments. We show that ongoing experiments can immediately impact deep open questions regarding the so-called ``O(2) rotor model'' at finite chemical potential, and the fermionic Mott insulator/metal crossover.

Hazzard, Kaden; Mueller, Erich

2010-03-01

410

Cold cathode vacuum gauging system  

SciTech Connect

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.

Denny, Edward C. (Knoxville, TN)

2004-03-09

411

Micro-Kelvin cold molecules.  

SciTech Connect

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.

Strecker, Kevin E.; Chandler, David W.

2009-10-01

412

Assessment of some shock absorbing insoles.  

PubMed

Due to the increase in prescription of insoles to relieve symptoms due to skeletal shocks at heel strike a pilot study was initiated to look at some materials used for this purpose. Five materials were examined (Plastazote, Spenco, Sorbothane, Poron (PPT) and Viscolas) by two methods. The first method used an accelerometer mounted between the teeth of one of the authors (PR) to record skeletal shock. The second method used a force plate to record the shock produced by dropping a ball-bearing onto the insoles from a standard height. The results showed that Plastazote is poor at absorbing shock with Spenco and Sorbothane being quite good. The best insole materials tested were Poron (PPT) and Viscolas with the latter being marginally superior. No account was taken of degradation of the materials in use except that Plastazote worn for 72 hours was also used in the study, this producing the worst results. PMID:3725565

Pratt, D J; Rees, P H; Rodgers, C

1986-04-01

413

Novel active vibration absorber with magnetorheological fluid  

NASA Astrophysics Data System (ADS)

Disturbing vibrations diminish the performance of technical high precision devices significantly. In search of a suitable solution for reducing these vibrations, a novel concept of active vibration reduction was developed which exploits the special properties of magnetorheological fluids. In order to evaluate the concept of such an active vibration absorber (AVA) a demonstrator was designed and manufactured. This demonstrator generates a force which counteracts the motion of the vibrating body. Since the counterforce is generated by a centrifugal exciter, the AVA provides the capability to compensate vibrations even in two dimensions. To control the strength of the force transmitted to the vibrating body, the exciter is based on a tunable MR coupling. The AVA was integrated in an appropriate testing device to investigate its performance. The recorded results show a significant reduction of the vibration amplitudes by an order of magnitude.

Gerlach, T.; Ehrlich, J.; Böse, H.

2009-02-01

414

Porous carbon nanoparticle networks with tunable absorbability.  

PubMed

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

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

2013-01-01

415

Porous Carbon Nanoparticle Networks with Tunable Absorbability  

NASA Astrophysics Data System (ADS)

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.

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

2013-08-01

416

Porous Carbon Nanoparticle Networks with Tunable Absorbability  

PubMed Central

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

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

2013-01-01

417

Electromagnetic radiation absorbers and modulators comprising polyaniline  

DOEpatents

A composition for absorbing electromagnetic radiation, wherein said electromagnetic radiation possesses a wavelength generally in the range of from about 1000 Angstroms to about 50 meters, wherein said composition comprises a polyaniline composition of the formula ##STR1## where y can be equal to or greater than zero, and R.sup.1 and R.sup.2 are independently selected from the group containing of H, --OCH.sub.3, --CH.sub.3, --F, --Cl, --Br, --I, NR.sup.3 .sub.2, --NHCOR.sup.3, --OH, --O.sup.-, SR.sup.3, --OCOR.sup.3, --NO.sub.2, --COOH, --COOR.sup.3, --COR.sup.3, --CHO, and --CN, where R.sup.3 is a C.sub.1 to C.sub.8 alkyl, aryl or aralkyl group.

Epstein, Arthur J. (Bexley, OH); Ginder, John M. (Columbus, OH); Roe, Mitchell G. (Columbus, OH); Hajiseyedjavadi, Hamid (Columbus, OH)

1992-01-01

418

Absorbed doses from temporomandibular joint radiography  

SciTech Connect

Thermoluminescent dosimeters were used in a tissue-equivalent phantom to measure doses of radiation absorbed by various structures in the head when the temporomandibular joint was examined by four different radiographic techniques--the transcranial, transorbital, and sigmoid notch (Parma) projections and the lateral tomograph. The highest doses of radiation occurred at the point of entry for the x-ray beam, ranging from 112 mrad for the transorbital view to 990 mrad for the sigmoid notch view. Only the transorbital projection a radiation dose to the lens of the eye. Of the four techniques evaluated, the lateral tomograph produced the highest doses to the pituitary gland and the bone marrow, while the sigmoid notch radiograph produced the highest doses to the parotid gland.

Brooks, S.L.; Lanzetta, M.L.

1985-06-01

419

Skin interaction with absorbent hygiene products.  

PubMed

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

Runeman, Bo

2008-01-01

420

Effects of concentration prior to cold-stabilization on anthocyanin stability in concord grape juice.  

PubMed

The color of Concord grape juice produced by concentration before cold-stabilization and detartration (direct-to-concentrate, DTC) was compared to juice produced via cold-stabilization prior to concentration (standard concentrate, SC) and evaluated by several metrics. Using the Boulton copigmentation assay, the majority of the absorbance at 520 nm in bottled SC juice (72%) was due to monomeric anthocyanins. Following reconstitution, DTC juice had a 63% greater absorbance at 520 nm than SC juice. A significant loss of anthocyanins was observed using a paired t test during cold-stabilization of single-strength juice during SC processing (mean loss: 79 mg/L as cyanidin-3-glucoside, 23% of total anthocyanins), while no significant loss of anthocyanins or change in other color metrics was observed during cold-stabilization of DTC concentrate. The concentration of anthocyanins in the SC bitartrate crystals was 0.80% w/w compared to 0.13% w/w in the DTC bitartrate crystals. Between DTC and SC, no difference in copigmentation was observed in cold-stabilized concentrate or reconstituted juice, indicating that the increased stability of anthocyanins could not be credited to greater copigmentation in DTC during detartration. HPLC analyses indicated that anthocyanin species with higher pKh and thus proportionally greater flavylium ion concentration at juice pH are preferentially lost during SC processing. The proportional changes in color metrics during shelf life stability testing (0-16 weeks, 2-30 °C) were not significantly different between SC and DTC juices. PMID:20929230

Alongi, Kristin S; Padilla-Zakour, Olga I; Sacks, Gavin L

2010-11-10

421

Application of magnetorheological fluid in industrial shock absorbers  

NASA Astrophysics Data System (ADS)

The paper presents investigation results of a semi-active industrial shock absorber with magnetorheological (MR) fluid, which is capable of controlling the stopping process of moving objects, e.g. on transportation lines. The proposed solution makes it possible to adjust the braking force (by electronic controller) to the kinetic energy of the moving object. The paper presents an overview of passive shock absorbers. Next, the design concept of a semi-active shock absorber with the MR fluid is proposed. The theoretical model and the simulation model of the MR absorber and the stopping process are presented. The paper reports investigations of a prototype MR shock absorber used to stop a mass moving on an inclined plane. The braking force of the absorber was changed by an electronic control system according to the current position of the moving mass. Finally, the simulation and investigation results are discussed and compared.

Milecki, Andrzej; Hauke, Miko?aj

2012-04-01

422

An acoustic absorber implemented by graded index phononic crystals  

NASA Astrophysics Data System (ADS)

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.

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

2014-06-01

423

A numerical study of double-leaf microperforated panel absorbers  

Microsoft Academic Search

Microperforated panel (MPP) absorbers are promising as a basis for the next-generation of sound absorbing materials. Typically, they are backed by an air-cavity in front of a rigid wall such as a ceiling or another interior surface of a room. Indeed, to be effective, MPP absorbers require the Helmholtz-type resonance formed with the backing cavity. Towards the creation of an

Kimihiro Sakagami; Masayuki Morimoto; Wakana Koike

2006-01-01

424

Isotropic Mie resonance-based metamaterial perfect absorber  

NASA Astrophysics Data System (ADS)

An isotropic Mie resonance-based metamaterial perfect absorber with near unity absorbance is experimentally and numerically demonstrated. The metamaterial is constructed with an array of dielectric cubes and a metallic ground plane. The absorption peak of the metamaterial perfect absorber is dependent on the permittivity and the side length of the dielectric cubes. A good agreement between experimental and simulated result at X band absorption is achieved.

Liu, Xiaoming; Zhao, Qian; Lan, Chuwen; Zhou, Ji

2013-07-01

425

Refractory plasmonics with titanium nitride: broadband metamaterial absorber.  

PubMed

A high-temperature stable broadband plasmonic absorber is designed, fabricated, and optically characterized. A broadband absorber with an average high absorption of 95% and a total thickness of 240 nm is fabricated, using a refractory plasmonic material, titanium nitride. This absorber integrates both the plasmonic resonances and the dielectric-like loss. It opens a path for the interesting applications such as solar thermophotovoltaics and optical circuits. PMID:25327161

Li, Wei; Guler, Urcan; Kinsey, Nathaniel; Naik, Gururaj V; Boltasseva, Alexandra; Guan, Jianguo; Shalaev, Vladimir M; Kildishev, Alexander V

2014-12-17

426

Selection of new absorbents for carbon dioxide capture  

Microsoft Academic Search

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

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

2007-01-01

427

Graft-copolymerization of PVC with polymerizable UV absorbers  

Microsoft Academic Search

Polyvlnyl chloride has been grafted with two different monofunctional polymerizable ultraviolet (UV) absorbers, 4-methacryloyloxy-2-hydroxybenzophenone and 2(2-hydroxy-4-methacryloyloxyphenyl) 2H-5-methoxy-benzotriazole. PVC was activated by dehydrochlorinating it in pyridine and subsequently grafted with the monomeric UV absorbers in tetrahydrofuran by free radical polymerization. The molar masses of the resulting grafted polymers and the distribution of the UV absorber moleties along different molar mass fractions

A. Al-Mobasher; S. Attari; H. Pasch; K. F. Shuhaibar; F. A. Rasoul

1991-01-01

428

Vertical-plane pendulum absorbers for minimizing helicopter vibratory loads  

NASA Technical Reports Server (NTRS)

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.

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

1974-01-01

429

Cold Fusion Has Now Come Out of the Cold  

NASA Astrophysics Data System (ADS)

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.

Storms, Edmund

2003-10-01

430

Decomposition-based recovery of absorbers in turbid media  

SciTech Connect

We suggest that the concept of the point-spread function traditionally used to predict the blurred image pattern of various light sources embedded inside turbid media can be generalized under certain conditions to predict also the presence and location of spatially localized absorbing inhomogeneities based on shadow point-spread functions associated with each localized absorber in the medium. The combined image obtained from several absorbers can then be decomposed approximately into the arithmetic sums of these individual shadow point-spread functions with suitable weights that can be obtained from multiple-regression analysis. This technique permits the reconstruction of the location of absorbers.

Campbell, S. D.; Goodin, I. L.; Grobe, S. D.; Su, Q.; Grobe, R. [Intense Laser Physics Theory Unit and Department of Physics, Illinois State University, Normal, Illinois 61790-4560 (United States)

2007-12-15

431

Wideband Aural Acoustic Absorbance Predicts Conductive Hearing Loss in Children  

PubMed Central

Objective This study tested the hypothesis that wideband aural absorbance predicts conductive hearing loss (CHL) in children medically classified as having otitis media with effusion. Design Absorbance was measured in the ear canal over frequencies from 0.25 to 8 kHz at ambient pressure or as a swept tympanogram. CHL was defined using criterion air-bone gaps of 20, 25 and 30 dB at octaves from 0.25 to 4 kHz. A likelihood-ratio predictor of CHL was constructed across frequency for ambient absorbance and across frequency and pressure for absorbance tympanometry. Performance was evaluated at individual frequencies and for any frequency at which a CHL was present. Study Sample Absorbance and conventional 226-Hz tympanograms were measured in children of age 3 to 8 years with CHL and with normal hearing. Results Absorbance was smaller at frequencies above 0.7 kHz in the CHL group than the control group. Based on the area under the receiver operating characteristic curve, wideband absorbance in ambient and tympanometric tests were significantly better predictors of CHL than tympanometric width, the best 226-Hz predictor. Accuracies of ambient and tympanometric wideband absorbance did not differ. Conclusions Absorbance accurately predicted CHL in children and was more accurate than conventional 226-Hz tympanometry. PMID:23072655

Keefe, Douglas H.; Sanford, Chris A.; Ellison, John C.; Fitzpatrick, Denis F.; Gorga, Michael P.

2013-01-01

432

Optimal active vibration absorber: Design and experimental results  

NASA Technical Reports Server (NTRS)

An optimal active vibration absorber can provide guaranteed closed-loop stability and control for large flexible space structures with collocated sensors/actuators. The active vibration absorber is a second-order dynamic system which is designed to suppress any unwanted structural vibration. This can be designed with minimum knowledge of the controlled system. Two methods for optimizing the active vibration absorber parameters are illustrated: minimum resonant amplitude and frequency matched active controllers. The Controls-Structures Interaction Phase-1 Evolutionary Model at NASA LaRC is used to demonstrate the effectiveness of the active vibration absorber for vibration suppression. Performance is compared numerically and experimentally using acceleration feedback.

Lee-Glauser, Gina; Juang, Jer-Nan; Sulla, Jeffrey L.

1992-01-01

433

The Warm, Cold and Very Cold Dusty Universe  

E-print Network

We are living in a dusty universe: dust is ubiquitously seen in a wide variety of astrophysical environments, ranging from circumstellar envelopes around cool red giants to supernova ejecta, from diffuse and dense interstellar clouds and star-forming regions to debris disks around main-sequence stars, from comets to interplanetary space to distant galaxies and quasars. In this review I focus on interstellar grains, with particular emphasis on the extinction (absorption plus scattering) and emission properties of cold submicron-sized ``classical'' grains which, in thermal equilibrium with the ambient interstellar radiation field, obtain a steady-state temperature of \\~15--25K, warm nano-sized (or smaller) "ultrasmall" grains which are, upon absorption of an energetic photon, transiently heated to temperatures as high as a few hundred to over 1000K, and the possible existence of a population of very cold (< 10K) dust. Whether dust grains can really get down to "temperature" less than the 2.7K cosmic microwav...

Li, A

2005-01-01

434

The Warm, Cold and Very Cold Dusty Universe  

E-print Network

We are living in a dusty universe: dust is ubiquitously seen in a wide variety of astrophysical environments, ranging from circumstellar envelopes around cool red giants to supernova ejecta, from diffuse and dense interstellar clouds and star-forming regions to debris disks around main-sequence stars, from comets to interplanetary space to distant galaxies and quasars. In this review I focus on interstellar grains, with particular emphasis on the extinction (absorption plus scattering) and emission properties of cold submicron-sized ``classical'' grains which, in thermal equilibrium with the ambient interstellar radiation field, obtain a steady-state temperature of \\~15--25K, warm nano-sized (or smaller) "ultrasmall" grains which are, upon absorption of an energetic photon, transiently heated to temperatures as high as a few hundred to over 1000K, and the possible existence of a population of very cold (< 10K) dust. Whether dust grains can really get down to "temperature" less than the 2.7K cosmic microwave background radiation temperature will also be discussed. The robustness of the silicate-graphite-PAHs interstellar dust model is demonstrated by showing that the infrared emission predicted from this model closely matches that observed for the Milky Way, the Small Magellanic Cloud, and the ringed Sb galaxy NGC7331.

Aigen Li

2005-03-25

435

Cold signal transduction and its interplay with phytohormones during cold acclimation.  

PubMed

Cold stress is a major environmental factor that affects plant growth, development, productivity and distribution. In higher plants, the known major cold signaling pathway is the C-repeat (CRT)-binding factor/dehydration-responsive element (DRE) binding factor (CBF/DREB)-mediated transcriptional regulatory cascade, which is essential for the induction of a set of cold responsive (COR) genes. Recent studies indicate that various plant hormones are also involved in responses to cold stress. This review summarizes recent progress in cold signaling and our understanding of phytohormone signaling in the regulation of plant responses to cold stress. PMID:25189343

Shi, Yiting; Ding, Yanglin; Yang, Shuhua

2015-01-01

436

Probing Cold Dense Nuclear Matter  

E-print Network

The protons and neutrons in a nucleus can form strongly correlated nucleon pairs. Scattering experiments, where a proton is knocked-out of the nucleus with high momentum transfer and high missing momentum, show that in 12C the neutron-proton pairs are nearly twenty 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.

R. Subedi; R. Shneor; P. Monaghan; B. D. Anderson; K. Aniol; J. Annand; J. Arrington; H. Benaoum; F. Benmokhtar; W. Bertozzi; W. Boeglin; J. -P. Chen; Seonho Choi; E. Cisbani; B. Craver; S. Frullani; F. Garibaldi; S. Gilad; R. Gilman; O. Glamazdin; J. -O. Hansen; D. W. Higinbotham; T. Holmstrom; H. Ibrahim; R. Igarashi; C. W. de Jager; E. Jans; X. Jiang; L. Kaufman; A. Kelleher; A. Kolarkar; G. Kumbartzki; J. J. LeRose; R. Lindgren; N. Liyanage; D. J. Margaziotis; P. Markowitz; S. Marrone; M. Mazouz; D. Meekins; R. Michaels; B. Moffit; C. F. Perdrisat; E. Piasetzky; M. Potokar; V. Punjabi; Y. Qiang; J. Reinhold; G. Ron; G. Rosner; A. Saha; B. Sawatzky; A. Shahinyan; S. Širca; K. Slifer; P. Solvignon; V. Sulkosky; G. Urciuoli; E. Voutier; J. W. Watson; L. B. Weinstein; B. Wojtsekhowski; S. Wood; X. -C. Zheng; L. Zhu

2009-08-11

437

Cold cathode vacuum discharge tube  

DOEpatents

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.

Boettcher, G.E.

1998-03-10

438

Microwave absorbing properties and structural design of microwave absorbers based on polyaniline and polyaniline/magnetite nanocomposite  

NASA Astrophysics Data System (ADS)

Double-layer absorbers with enhanced microwave absorbing properties were designed based on polyaniline and polyaniline/magnetite composite with a total thickness of 1 mm. The double-layer microwave absorbers have better microwave absorbing properties than those of single-layer microwave absorbers, and the microwave absorbing properties of the double-layer structure are influenced by the coupling interactions between the absorbing layer and matching layer. When the absorbing layer is PANI with a thickness of 0.4 mm, and the matching layer is PANI/Fe3O4 composite with a thickness of 0.6 mm, the minimum reflection loss (RL) reaches -42 dB at 29.27 GHz and the absorption bandwidth with RL below -10 dB is about 11.8 GHz. While when PANI and PANI/Fe3O4 composite are acted as matching layer and absorbing layer, respectively, with the same thickness of 0.5 mm, a minimum RL value of -54 dB is observed at 33.72 GHz and the absorption bandwidth is about 11.28 GHz ranging from 27.24 to 38.52 GHz with the RL value below -10 dB.

Xu, Fenfang; Ma, Li; Huo, Qisheng; Gan, Mengyu; Tang, Jihai

2015-01-01

439

MoSi absorber photomask for 32nm node  

NASA Astrophysics Data System (ADS)

The development of semiconductor process for 32nm node is in progress. Immersion lithography has been introduced as an extension of 193nm lithograpy. In addition, DPL (Double patterning lithography) is becoming a strong candidate of next generation lithography. The extension of optical lithography increases more mask complexity and tighter specification of photomasks. CD performance is the most important issue in the advanced photomask technology. However, it is expected that conventional mask cannot satisfy the required mask specifications for 32nm node and beyond. Most of CD errors are contributed to the dry etching process. Mask CD variation is greatly influenced by the loading effect from dry etching of the absorber. As the required accuracy of the mask arises, Cr absorber thickness has been gradually thinner. CD linearity with the thinner Cr absorber thickness has better performance. However, it is difficult to apply thinner Cr absorber thickness simply under the condition of OD > 3, which is needed for wafer printing. So, we adopted MoSi absorber instead of conventional Cr absorber, because MoSi absorber has less micro and global loading effect than that of Cr absorber. By using MoSi absorber, we can reduce Cr thickness as a hardmask. The thinner Cr hardmask allows for reduce resist thickness and become same condition for conventional EB resist lithography. The lithography performances were confirmed by the simulation and wafer printing. The new MoSi absorber mask behaves similar to the conventional Cr absorber mask. The adoption of super thin Cr as a hardmask made it possible to reduce resist thickness. By the application of the thin resist and the latest tools, we'll improve the mask performance to meet the 32 nm generation specification.

Konishi, Toshio; Kojima, Yosuke; Takahashi, Hiroyuki; Tanabe, Masato; Haraguchi, Takashi; Lamantia, Matthew; Fukushima, Yuichi; Okuda, Yoshimitsu

2008-05-01

440

Iron chalcogenide photovoltaic absorbers -- problems and opportunities  

NASA Astrophysics Data System (ADS)

Realizing new, efficient solar absorbers containing earth-abundant materials represents a critical element for expanding the reach of photovoltaic (PV) technologies, meeting growing energy needs. The use of Fe in PV was proposed more than 25 years ago in the form of FeS2 pyrite. We report a concerted and integrated theoretical and experimental study that provides new insight into the problem of FeS2. Computational results on FeS2 reveal high formation energies for bulk point defects and small formation energies for S vacances near the surface. These findings are consistent with the formation of metallic S-deficient binary Fe-S phases at low temperatures that affect the electrical and optical properties of thin films. We have used this new understanding to propose and implement design rules for identifying new Fe-containing materials---Fe2SiS4 and Fe2GeS4-- that may circumvent the limitations of pyrite. These ternary materials are p-type with direct allowed optical band gaps near 1.5 eV.

Kokenyesi, Robert; Jieratum, Vorranutch; Altschul, Emmeline; Keszler, Douglas; Ravichandran, Ram; Pelatt, Brian; Wager, John; Yu, Liping; Lany, Stephan; Zunger, Alex

2012-02-01

441

Multifunctional Space Evaporator-Absorber-Radiator (SEAR)  

NASA Technical Reports Server (NTRS)

A system for non-venting thermal control for spacesuits was built by integrating two previously developed technologies, namely NASA's Spacesuit Water Membrane Evaporator (SWME), and Creare's flexible version of the Lithium Chloride Absorber Radiator (LCAR). This SEAR system was tested in relevant thermal vacuum conditions. These tests show that a 1 sq m radiator having about three times as much absorption media as in the test article would be required to support a 7 hour spacewalk. The serial flow arrangement of the LCAR of the flexible version proved to be inefficient for venting non-condensable gas (NCG). A different LCAR packaging arrangement was conceived wherein the Portable Life Support System (PLSS) housing would be made with a high-strength carbon fiber composite honeycomb, the cells of which would be filled with the chemical absorption media. This new packaging reduce the mass and volume impact of the SEAR on the Portable Life Support System (PLSS) compared to the flexible design. A 0.2 sq m panel with flight-like honeycomb geometry is being constructed and will be tested in thermal and thermal vacuum conditions. Design analyses forecast improved system performance and improved NCG control. A flight-like regeneration system also is also being built and tested. Design analyses for the structurally integrated prototype as well as the earlier test data show that SEAR is not only practical for spacesuits but also has useful applications in spacecraft thermal control.

Bue, Grant C.; Hodgson, Ed; Izenson, Mike; Chen, Weibo

2013-01-01

442

Light absorbing carbon emissions from commercial shipping  

NASA Astrophysics Data System (ADS)

Extensive measurements of the emission of light absorbing carbon aerosol (LAC) from commercial shipping are presented. Vessel emissions were sampled using a photoacoustic spectrometer in the Gulf of Mexico region. The highest emitters (per unit fuel burnt) are tug boats, thus making significant contributions to local air quality in ports. Emission of LAC from cargo and non cargo vessels in this study appears to be independent of engine load. Shipping fuel consumption data (2001) was used to calculate a global LAC contribution of 133(+/-27) Ggyr-1, or ~1.7% of global LAC. This small fraction could have disproportionate effects on both air quality near port areas and climate in the Arctic if direct emissions of LAC occur in that region due to opening Arctic sea routes. The global contribution of this LAC burden was investigated using the MOZART model. Increases of 20-50 ng m-3 LAC (relative increases up to 40%) due to shipping occur in the tropical Atlantic, Indonesia, central America and the southern regions of South America and Africa.

Lack, Daniel; Lerner, Brian; Granier, Claire; Baynard, Tahllee; Lovejoy, Edward; Massoli, Paola; Ravishankara, A. R.; Williams, Eric

2008-07-01

443

International workshop on cold neutron sources  

SciTech Connect

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.

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

444

Cold stream stability during minor mergers  

E-print Network

We use high-resolution Eulerian simulations to study the stability of cold gas flows in a galaxy size dark matter halo (10^12 Msun) at redshift z=2. Our simulations show that a cold stream penetrating a hot gaseous halo is stable against thermal convection and Kelvin-Helmholtz instability. We then investigate the effect of a satellite orbiting the main halo in the plane of the stream. The satellite is able to perturb the stream and to inhibit cold gas accretion towards the center of the halo for 0.5 Gyr. However, if the supply of cold gas at large distances is kept constant, the cold stream is able to re-establish itself after 0.3 Gyr. We conclude that cold streams are very stable against a large variety of internal and external perturbations.

Wang, Liang; Feng, Longlong; Macciò, Andrea V; Chang, Jiang; Kang, Xi

2014-01-01

445

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

PubMed

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

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

2014-04-23

446

First detection of cold dust in the northern shell of NGC 5128 (Centaurus A)  

NASA Astrophysics Data System (ADS)

Deep far-infrared (FIR) imaging data obtained with ISOPHOT at 90 ?m, 150 ?m, and 200 ?m detected the thermal emission from cold dust in the northern shell region of NGC 5128 (Centaurus A), where previously neutral hydrogen and molecular gas has been found. A somewhat extended FIR emission region is present in both the 150 ?m and 200 ?m map, while only an upper flux limit could be derived from the 90 ?m data. The FIR spectral energy distribution can be reconciled with a modified blackbody spectrum with very cold dust color temperatures and emissivity indices in the range 13 K < TDust < 15.5 K and 2 > ? > 1, respectively, where the data favor the low temperature end. A representative value for the associated dust mass is MDust ? 7×104 M?, which together with the HI gas mass gives a gas-to-dust ratio of ?300, close the average values of normal inactive spiral galaxies. This value, in conjunction with the atomic to molecular gas mass ratio typical for a spiral galaxy, indicates that the interstellar medium (ISM) from the inner part of a captured disk galaxy is likely the origin of the outlying gas and dust. These observations are in agreement with recent theoretical considerations that in galaxy interactions leading to stellar shell structures the less dissipative clumpy component of the ISM from the captured galaxy can lead to gaseous shells. Alternatively, the outlying gas and dust could be a rotating ring structure resulting from an interaction or even late infall of tidal material of a merger in the distant past. With all three components (atomic gas, molecular gas, dust) of the ISM present in the northern shell region, local star formation may account for the chains of young blue stars surrounding the region to the east and north. The dust cloud may also be involved in the disruption of the large scale radio jet before entering the brighter region of the northern radio lobe. Based on observations with ISO, an ESA project with instruments funded by ESA Member States (especially the PI countries: France, Germany, The Netherlands and the UK) and with the participation of ISAS and NASA.

Stickel, M.; van der Hulst, J. M.; van Gorkom, J. H.; Schiminovich, D.; Carilli, C. L.

2004-02-01

447

International workshop on cold neutron sources  

Microsoft Academic Search

The first meeting devoted to cold neutron sources was held at the Los Alamos National Laboratory on March 5 to 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

G. J. Russell; C. D. West

1991-01-01

448

Should the exchange rate be a shock absorber?  

Microsoft Academic Search

This paper examines the welfare case for the exchange rate as a “shock absorber”, cushioning an economy in face of shocks to world demand for its good. We provide an example in which, although the exchange rate acts perfectly as a shock absorber, stabilizing output around the natural rate, and eliminating the impact of nominal rigidities, it may in fact

Michael B. Devereux

2004-01-01

449

A nonlinear dynamic model of a monotube shock absorber  

Microsoft Academic Search

A physics-based model for a high pressure monotube shock absorber is proposed by which the nonlinear dynamic behavior of these dampers can be analyzed. The bond graph technique is used to model these shock absorbers accurately over a wide range of stroking frequencies (1 to 20 Hz) and to identify the interaction between mechanical, fluid, and thermodynamic elements. Various phenomena

R. Mollica; K. Youcef-Toumi

1997-01-01

450

An adaptive tuned vibration absorber based on multilayered MR elastomers  

NASA Astrophysics Data System (ADS)

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.

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

2015-04-01

451

Resveratrol Is Absorbed in the Small Intestine as Resveratrol Glucuronide  

Microsoft Academic Search

We have studied the absorption and metabolism of resveratrol in the jejunum in an isolated rat small intestine model. Only small amounts of resveratrol were absorbed across the enterocytes of the jejunum and ileum unmetabolised. The major compound detected on the serosal side was the glucuronide conjugate of resveratrol (96.5% ± 4.6 of the amount absorbed) indicating the susceptibility of

Gunter Kuhnle; Jeremy P. E. Spencer; George Chowrimootoo; Hagen Schroeter; Edward S. Debnam; S. Kaila S. Srai; Catherine Rice-Evans; Ulrich Hahn

2000-01-01

452

Adaptive Tuned Vibration Absorber based on Magnetorheological Elastomer  

Microsoft Academic Search

This study presents an adaptive tuned vibration absorber (ATVA) which is based on magnetorheological elastomer (MRE). Traditional dynamic absorber has limited its application and vibration absorption capacity for its narrow working frequency bandwidth. MRE is a kind of smart material whose modulus can be controlled by applied magnetic field. Based on MREs, an ATVA which works on shear mode is

H. X. Deng; X. L. Gong

2007-01-01

453

Numerical and experimental investigation of nonlinear properties of rubber absorber  

E-print Network

Numerical and experimental investigation of nonlinear properties of rubber absorber in rail, Shanghai, 201804 Abstract: A dynamic nonlinear model of rubber absorber in railway fastening is proposed in this paper based on a superposition principal demonstrating that the restoring force of rubber components

Paris-Sud XI, Université de

454

Evaluation of commercial fuel tank water absorbers. Final report  

SciTech Connect

This report describes the laboratory evaluation of three types of commercial fuel tank water absorber cartridges and a limited field test of one type. Evaluation included absorbance effectiveness, possible deleterious effects on the fuel, and design integrity. Results are discussed together with the potential for use by the Army.

Williams, W.R.

1994-11-01

455

Shock-absorbing caster wheel is simple and compact  

NASA Technical Reports Server (NTRS)

Compact shock-absorbing caster wheel mitigates or absorbs shock by a compressible tire which deforms into a cavity between its inner edge and the wheel hub. A tee-shaped annular ring embedded in the tire distributes loads more uniformly throughout both wheel and tire.

Kindley, R. J.

1968-01-01

456

Shape optimization for absorber plates of solar air collectors  

Microsoft Academic Search

Solar air heaters can be used for many applications at low and moderate temperatures. There are different factors affecting the solar air heater efficiency, e.g. collector length, collector depth, type of absorber plate, glass cover plate, wind speed, etc. The absorber shape factor is the most important parameter in the design for any type of solar air heater. Increasing the

K. Me?árik

1998-01-01

457

Evaluating a super absorbent dressing (Flivasorb) in highly exuding wounds.  

PubMed

This article reports an observational evaluation of 19 patients with highly exuding wounds. Flivasorb was used as a super absorbent dressing that could remove the harmful exudate fluid and promote a healthy wound bed. The outcomes demonstrated that Flivasorb is successfully absorbs large amounts of fluid, reduces the number of dressing changes required and therefore, reduces the cost of the patient's care. PMID:20505605

Verrall, Debby; Coulborn, Anna; Bree-Aslan, Cathie

458

Nylon shock absorber prevents injury to parachute jumpers  

NASA Technical Reports Server (NTRS)

Nylon shock absorbers reduce the canopy-opening shock of a parachute to a level that protects the wearer from injury. A shock absorber is mounted on each of the four risers between the shroud lines and the harness. Because of their size and location, they pose no problem in repacking the chute and harness after a jump.

Mandel, J. A.

1966-01-01

459

On the Absorption Mechanism of Ultra Thin Absorbers  

Microsoft Academic Search

Ultra thin absorbers are studied in detail to provide a comprehensive model for their absorption mechanism. It is shown that the transmission line (TML) approach is not able to model the absorber frequency response correctly. It results in large errors when the thickness to wavelength (d\\/?) ratio is below a certain level. It is explained that large amplitudes of high

Alireza Kazemzadeh; Anders Karlsson

2010-01-01

460

Evaluation of the growth of microorganisms on diaper absorbent materials  

Microsoft Academic Search

Summary Methods were developed to study the effects of absorbent materials from diapers on microbial survival, growth and toxic shock syndrome toxin-1 (TSST-1) production under specified in vitro conditions. Growth of representative skin and fecal flora organisms was equivalent in cultures in which materials from cotton cloth diapers, disposable diapers or disposable diapers containing absorbent gelling material were added as

B. H. Keswick

1988-01-01

461

Broadband absorber leaves optical systems in the dark  

SciTech Connect

To get around various shortcomings of optically black surfaces, the feasibility of creating a very broadband absorber using a composite material known as carbon-bonded carbon fiber (CBCF) was studied. It was found that CBCF is uniquely suited for use as an optical absorber for a variety of reasons.

Pearce, J.

1992-01-01

462

Application of Ferrite to Electromagnetic Wave Absorber and its Characteristics  

Microsoft Academic Search

An electromagnetic wave absorber utilizing ferrite or rubber ferrite composed of ferrite powder and rubber is described. In our investigation, the existence of a matching frequency fm and a matching thickness tm has been found. The terms fm and tm mean that the ferrite which is backed with a conducting plate can be a perfect absorber only under the conditions

YOSHIYUKI NAITO; KUNIHIRO SUETAKE

1971-01-01

463

SPC12-301: Thermal performances of solar energy absorbers  

Microsoft Academic Search

The testing scheme applies to the case of absorbers where the heat carrier is a liquid passing from a single inlet to a single outlet. The absorbers are intended as part of a roof and must be tested in a standardized construction. Thermal efficiency, losses and the influence of the angle of incidence are discussed. The total solar flux in

H. E. B. Andersson; H. E. B

1979-01-01

464

An Absorbing Look at Terry-Cloth Towels  

ERIC Educational Resources Information Center

This article describes a lesson where students explore the absorbency of several towels with different weaves and weights. The lesson follows the 5E learning-cycle model and incorporates engineering in the sense of product testing with a focus on the relationship between the weave of a towel and its absorbency. The National Science Education…

Moyer, Richard; Everett, Susan

2010-01-01

465

NON-UNISON DYNAMICS OF MULTIPLE CENTRIFUGAL PENDULUM VIBRATION ABSORBERS  

Microsoft Academic Search

Centrifugal pendulum vibration absorber (CPVA) systems are used to decrease steady state torsional vibration levels and extend operating ranges for rotating and reciprocating machinery. They are typically sized and designed for a given harmonic using the assumption that a set of identical absorbers move in exact unison. Herein an investigation is carried out to determine the consequences, in terms of

C.-P. Chao; C.-T. Lee; S. W. Shaw

1997-01-01

466

International development and advances in solar selective absorbers  

Microsoft Academic Search

This study covers advances in solar selective absorbers. The classes of selective absorbers are discussed along with their characteristics and physics. From much of the research and development on solar coatings in the 1970s and early 1980s only black chrome and nickel-pigmented aluminum have been largely commercially adopted. Black chrome still has the best proven overall operational characteristics for the

Carl M. Lampert

1997-01-01

467

Ultra-black nickel-phosphorus alloy optical absorber  

Microsoft Academic Search

To develop an optical absorber for use in the measurement of optical power, the authors have investigated and evaluated ultrablack films of nickel-phosphorus alloy which were deposited on substrates using an electroless plating process and subsequently etched. Results of varying the plating and etching bath components and conditions were studied. The result was a superior optical absorber which has a

S. Kodama; M. Horiuchi; T. Kunii; K. Kuroda

1990-01-01

468

Manipulating polarization of electromagnetic waves through controllable metamaterial absorber  

Microsoft Academic Search

In this presentation, we demonstrate an approach to manipulate electromagnetic waves with different polarizations through a controllable metamaterial absorber. The metamaterial absorber designed at 3.3 GHz is proposed by properly integrating resonant unit cells with orthogonal polarization sensitivity onto a dielectric substrate and coupling the unit cells with microwave diodes. Simulation and measurement results show that through tuning the bias

Bo Zhu; Ci Huang; Junming Zhao; Tian Jiang; Yijun Feng

2010-01-01

469

Cold as a therapeutic agent.  

PubMed

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

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

2006-05-01

470

HOM absorbers for ERL cryomodules at BNL  

SciTech Connect

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.

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

2009-09-20

471

Evaporative cooling enhanced cold storage system  

DOEpatents

The invention provides an evaporatively enhanced cold storage system wherein a warm air stream is cooled and the cooled air stream is thereafter passed into contact with a cold storage unit. Moisture is added to the cooled air stream prior to or during contact of the cooled air stream with the cold storage unit to effect enhanced cooling of the cold storage unit due to evaporation of all or a portion of the added moisture. Preferably at least a portion of the added moisture comprises water condensed during the cooling of the warm air stream.

Carr, Peter (Cary, NC)

1991-01-01

472

Evaporative cooling enhanced cold storage system  

DOEpatents

The invention provides an evaporatively enhanced cold storage system wherein a warm air stream is cooled and the cooled air stream is thereafter passed into contact with a cold storage unit. Moisture is added to the cooled air stream prior to or during contact of the cooled air stream with the cold storage unit to effect enhanced cooling of the cold storage unit due to evaporation of all or a portion of the added moisture. Preferably at least a portion of the added moisture comprises water condensed during the cooling of the warm air stream. 3 figures.

Carr, P.

1991-10-15

473

COLD1 Confers Chilling Tolerance in Rice.  

PubMed

Rice is sensitive to cold and can be grown only in certain climate zones. Human selection of japonica rice has extended its growth zone to regions with lower temperature, while the molecular basis of this adaptation remains unknown. Here, we identify the quantitative trait locus COLD1 that confers chilling tolerance in japonica rice. Overexpression of COLD1(jap) significantly enhances chilling tolerance, whereas rice lines with deficiency or downregulation of COLD1(jap) are sensitive to cold. COLD1 encodes a regulator of G-protein signaling that localizes on plasma membrane and endoplasmic reticulum (ER). It interacts with the G-protein ? subunit to activate the Ca(2+) channel for sensing low temperature and to accelerate G-protein GTPase activity. We further identify that a SNP in COLD1, SNP2, originated from Chinese Oryza rufipogon, is responsible for the ability of COLD(jap/ind) to confer chilling tolerance, supporting the importance of COLD1 in plant adaptation. PMID:25728666

Ma, Yun; Dai, Xiaoyan; Xu, Yunyuan; Luo, Wei; Zheng, Xiaoming; Zeng, Dali; Pan, Yajun; Lin, Xiaoli; Liu, Huanhuan; Zhang, Dajian; Xiao, Jun; Guo, Xiaoyu; Xu, Shujuan; Niu, Yuda; Jin, Jingbo; Zhang, Hui; Xu, Xun; Li, Legong; Wang, Wen; Qian, Qian; Ge, Song; Chong, Kang

2015-03-12

474

Review on Cold-Formed Steel Connections  

PubMed Central

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

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

2014-01-01

475

Cold vacuum drying facility design requirements  

SciTech Connect

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.

IRWIN, J.J.

1999-07-01

476

Performance evaluation of CFRP-rubber shock absorbers  

NASA Astrophysics Data System (ADS)

In the present work a numerical investigation on the energy absorbing capability of dedicated structural components made of a carbon fiber reinforced polymer and an emulsion polymerised styrene butadiene rubber is reported. The shock absorbers are devices designed to absorb large amounts of energy by sacrificing their own structural integrity. Their aim is to cushion the effects of an impact phenomenon with the intent to preserve other structures from global failure or local damaging. Another important role of shock absorbers is reducing the peak of the acceleration showed during an impact phenomenon. This effect is of considerable interest in the case of vehicles to preserve passengers' safety. Static and dynamic numerical results are compared with experimental ones in terms of mean crushing forces, energy and peak crushing. The global performance of the absorbers has been evaluated by referencing to a proposed quality index.

Lamanna, Giuseppe; Sepe, Raffaele

2014-05-01

477

Performance evaluation of CFRP-rubber shock absorbers  

SciTech Connect

In the present work a numerical investigation on the energy absorbing capability of dedicated structural components made of a carbon fiber reinforced polymer and an emulsion polymerised styrene butadiene rubber is reported. The shock absorbers are devices designed to absorb large amounts of energy by sacrificing their own structural integrity. Their aim is to cushion the effects of an impact phenomenon with the intent to preserve other structures from global failure or local damaging. Another important role of shock absorbers is reducing the peak of the acceleration showed during an impact phenomenon. This effect is of considerable interest in the case of vehicles to preserve passengers’ safety. Static and dynamic numerical results are compared with experimental ones in terms of mean crushing forces, energy and peak crushing. The global performance of the absorbers has been evaluated by referencing to a proposed quality index.

Lamanna, Giuseppe, E-mail: giuseppe.lamanna@unina2.it; Sepe, Raffaele, E-mail: giuseppe.lamanna@unina2.it [Department of Industrial and Information Engineering, Second University of Naples, via Roma, 29 - 81031 Aversa (Italy)

2014-05-15

478

Thermally induced nonlinear optical absorption in metamaterial perfect absorbers  

NASA Astrophysics Data System (ADS)

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.

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

2015-03-01

479

Multilayer metamaterial absorbers inspired by perfectly matched layers  

E-print Network

We derive periodic multilayer absorbers with effective uniaxial properties similar to perfectly matched layers (PML). This approximate representation of PML is based on the effective medium theory and we call it an effective medium PML (EM-PML). We compare the spatial reflection spectrum of the layered absorbers to that of a PML material and demonstrate that after neglecting gain and magnetic properties, the absorber remains functional. This opens a route to create electromagnetic absorbers for real and not only numerical applications and as an example we introduce a layered absorber for the wavelength of $8$~$\\mu$m made of SiO$_2$ and NaCl. We also show that similar cylindrical core-shell nanostructures derived from flat multilayers also exhibit very good absorptive and reflective properties despite the different geometry.

Pastuszczak, Anna; Antosiewicz, Tomasz J; Kotynski, Rafal

2014-01-01

480

Thermally Induced Nonlinear Optical Absorption in Metamaterial Perfect Absorbers  

E-print Network

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.

Guddala, Sriram; Ramakrishna, S Anantha

2015-01-01

481

Transcriptomic analysis of cold response in tomato fruits identifies dehydrin as a marker of cold stress  

Microsoft Academic Search

Tomato is sensitive to cold during vegetative growth, fruit set, development, and ripening. We have characterized the effect\\u000a of cold stress (6°C for up to 48 h) on the transcriptome of Micro-Tom tomato fruits during ripening by subtractive PCR. The\\u000a cold stress caused modifications in gene expression of housekeeping genes. From a total of 38 genes up-regulated by cold,\\u000a only

J. Weiss; M. Egea-Cortines

2009-01-01

482

Why Muscle is an Efficient Shock Absorber  

PubMed Central

Skeletal muscles power body movement by converting free energy of ATP hydrolysis into mechanical work. During the landing phase of running or jumping some activated skeletal muscles are subjected to stretch. Upon stretch they absorb body energy quickly and effectively thus protecting joints and bones from impact damage. This is achieved because during lengthening, skeletal muscle bears higher force and has higher instantaneous stiffness than during isometric contraction, and yet consumes very little ATP. We wish to understand how the actomyosin molecules change their structure and interaction to implement these physiologically useful mechanical and thermodynamical properties. We monitored changes in the low angle x-ray diffraction pattern of rabbit skeletal muscle fibers during ramp stretch compared to those during isometric contraction at physiological temperature using synchrotron radiation. The intensities of the off-meridional layer lines and fine interference structure of the meridional M3 myosin x-ray reflection were resolved. Mechanical and structural data show that upon stretch the fraction of actin-bound myosin heads is higher than during isometric contraction. On the other hand, the intensities of the actin layer lines are lower than during isometric contraction. Taken together, these results suggest that during stretch, a significant fraction of actin-bound heads is bound non-stereo-specifically, i.e. they are disordered azimuthally although stiff axially. As the strong or stereo-specific myosin binding to actin is necessary for actin activation of the myosin ATPase, this finding explains the low metabolic cost of energy absorption by muscle during the landing phase of locomotion. PMID:24465673

Kopylova, Galina V.; Fernandez, Manuel; Narayanan, Theyencheri

2014-01-01

483

Why muscle is an efficient shock absorber.  

PubMed

Skeletal muscles power body movement by converting free energy of ATP hydrolysis into mechanical work. During the landing phase of running or jumping some activated skeletal muscles are subjected to stretch. Upon stretch they absorb body energy quickly and effectively thus protecting joints and bones from impact damage. This is achieved because during lengthening, skeletal muscle bears higher force and has higher instantaneous stiffness than during isometric contraction, and yet consumes very little ATP. We wish to understand how the actomyosin molecules change their structure and interaction to implement these physiologically useful mechanical and thermodynamical properties. We monitored changes in the low angle x-ray diffraction pattern of rabbit skeletal muscle fibers during ramp stretch compared to those during isometric contraction at physiological temperature using synchrotron radiation. The intensities of the off-meridional layer lines and fine interference structure of the meridional M3 myosin x-ray reflection were resolved. Mechanical and structural data show that upon stretch the fraction of actin-bound myosin heads is higher than during isometric contraction. On the other hand, the intensities of the actin layer lines are lower than during isometric contraction. Taken together, these results suggest that during stretch, a significant fraction of actin-bound heads is bound non-stereo-specifically, i.e. they are disordered azimuthally although stiff axially. As the strong or stereo-specific myosin binding to actin is necessary for actin activation of the myosin ATPase, this finding explains the low metabolic cost of energy absorption by muscle during the landing phase of locomotion. PMID:24465673

Ferenczi, Michael A; Bershitsky, Sergey Y; Koubassova, Natalia A; Kopylova, Galina V; Fernandez, Manuel; Narayanan, Theyencheri; Tsaturyan, Andrey K

2014-01-01

484

A ‘special case’ between independence and interdependence: Cold War studies and Cold War politics in post-Cold War Switzerland  

Microsoft Academic Search

Switzerland only played a marginal role in the Cold War, even though the small country was situated very close to the central battleground of any potential armed conflict in Europe the ‘special role’ that Switzerland played in the East-West conflict was closely linked to its policy of strict neutrality. Swiss Cold War historians have focused on the reasons for the

Andreas Wenger; Christian Nuenlist

2008-01-01

485

Development of time projection chamber for precise neutron lifetime measurement using pulsed cold neutron beams  

E-print Network

A new time projection chamber (TPC) was developed for neutron lifetime measurement using a pulsed cold neutron spallation source at the Japan Proton Accelerator Research Complex (J-PARC). Managing considerable background events from natural sources and the beam radioactivity is a challenging aspect of this measurement. To overcome this problem, the developed TPC has unprecedented features such as the use of polyether-ether-ketone plates in the support structure and internal surfaces covered with $^6$Li-enriched tiles to absorb outlier neutrons. In this paper, the design and performance of the new TPC are reported in detail.

Y. Arimoto; N. Higashi; Y. Igarashi; Y. Iwashita; T. Ino; R. Katayama; R. Kitahara; M. Kitaguchi; H. Matsumura; K. Mishima; H. Oide; H. Otono; R. Sakakibara; T. Shima; H. M. Shimizu; T. Sugino; N. Sumi; H. Sumino; K. Taketani; G. Tanaka; M. Tanaka; K. Tauchi; A. Toyoda; T. Yamada; S. Yamashita; H. Yokoyama; T. Yoshioka

2015-03-27

486

Development of time projection chamber for precise neutron lifetime measurement using pulsed cold neutron beams  

E-print Network

A new time projection chamber (TPC) was developed for neutron lifetime measurement using a pulsed cold neutron spallation source at the Japan Proton Accelerator Research Complex (J-PARC). Managing considerable background events from natural sources and the beam radioactivity is a challenging aspect of this measurement. To overcome this problem, the developed TPC has unprecedented features such as the use of polyether-ether-ketone plates in the support structure and internal surfaces covered with $^6$Li-enriched tiles to absorb outlier neutrons. In this paper, the design and performance of the new TPC are reported in detail.

Arimoto, Y; Igarashi, Y; Iwashita, Y; Ino, T; Katayama, R; Kitahara, R; Kitaguchi, M; Matsumura, H; Mishima, K; Oide, H; Otono, H; Sakakibara, R; Shima, T; Shimizu, H M; Sugino, T; Sumi, N; Sumino, H; Taketani, K; Tanaka, G; Tanaka, M; Tauchi, K; Toyoda, A; Yamada, T; Yamashita, S; Yokoyama, H; Yoshioka, T

2015-01-01

487

Optical Precursor with Four-Wave Mixing and Storage Based on a Cold-Atom Ensemble  

NASA Astrophysics Data System (ADS)

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.

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

2015-03-01

488

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

NASA Astrophysics Data System (ADS)

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.

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

2014-06-01

489

Uptake of dissolved free amino acids by four cold-water coral species from the Mediterranean Sea  

NASA Astrophysics Data System (ADS)

Dissolved organic matter, which contains many compounds such as lipids, sugars and amino acids, is an important source of carbon and nitrogen for several symbiotic and asymbiotic tropical coral species. However, there is still no information on its possible uptake by cold-water coral species. In this study, we demonstrated that dissolved organic matter, in the form of dissolved free amino acids (DFAA), is actively absorbed by four cold-water coral species from the Mediterranean Sea. Although the uptake rates observed with 3 ?M DFAA concentration were one order of magnitude lower than those observed in tropical species, they corresponded to 12-50% of the daily excreted-nitrogen, and 16-89% of the daily respired-carbon of the cold-water corals. Consequently, DFAA, even at in situ concentrations lower than those tested in this study, can supply a significant amount of carbon and nitrogen to the corals, especially during periods when particulate food is scarce.

Gori, Andrea; Grover, Renaud; Orejas, Covadonga; Sikorski, Séverine; Ferrier-Pagès, Christine

2014-01-01

490

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

NASA Astrophysics Data System (ADS)

Numerical simulations are used to investigate the meteorological characteristics of the 31 January-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 the following: 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 snow cover variations and cloud microphysics are also examined. 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. Ice-dominant clouds enhance cold-air pool strength compared to liquid-dominant clouds by increasing nocturnal cooling and decreasing longwave cloud forcing.

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

2015-01-01

491

Age and Ethnic Differences in Cold Weather and Contagion Theories of Colds and Flu  

ERIC Educational Resources Information Center

Age and ethnic group differences in cold weather and contagion or germ theories of infectious disease were explored in two studies. A cold weather theory was frequently invoked to explain colds and to a lesser extent flu but became less prominent with age as children gained command of a germ theory of disease. Explanations of how contact with…

Sigelman, Carol K.

2012-01-01

492

WHAT IS A COLD? A "cold" is a syndrome of symptoms caused by  

E-print Network

numbers of ill students in close proximity to each other. Peak incidence of the common cold is in the late, these colors are commonly seen in the first 1-3 days. HOW IS A COLD DIAGNOSED? The diagnosis is made based system is your best ally against upper respiratory viruses. A common misconception is that colds last

Virginia Tech

493

Status of cold fusion (2010).  

PubMed

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. PMID:20838756

Storms, Edmund

2010-10-01

494

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".

495

Status of cold fusion (2010)  

NASA Astrophysics Data System (ADS)

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.

Storms, Edmund

2010-10-01

496

Simulation, Fabrication and Characterization of THz Metamaterial Absorbers  

PubMed Central

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

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

2012-01-01

497

Extreme warm absorber variability in the Seyfert galaxy Mrk 704  

NASA Astrophysics Data System (ADS)

Context. In about half of the Seyfert galaxies, the X-ray emission is absorbed by an optically thin, ionized medium, the so-called "warm absorber", whose origin and location is still a matter of debate. Aims: The aim of this paper is to constrain the warm absorber further by studying its variability. Methods: We analyzed the X-ray spectra of a Seyfert 1 galaxy, Mrk 704, which was observed twice, three years apart, by XMM-Newton. Results: The spectra were well fitted with a two-zones absorber, which possibly covers the source only partially. The parameters of the absorbing matter - column density, ionization state, covering factor - changed significantly between the two observations. Possible explanations for the more ionized absorber are a torus wind (the source is a polar scattering one) or, in the partial covering scenario, an accretion disk wind. The less ionized absorber is possibly composed of orbiting clouds in the surroundings of the nucleus, similarly to what was already found in other sources, most notably NGC 1365.

Matt, G.; Bianchi, S.; Guainazzi, M.; Longinotti, A. L.; Dadina, M.; Karas, V.; Malaguti, G.; Miniutti, G.; Petrucci, P. O.; Piconcelli, E.; Ponti, G.

2011-09-01

498

Innovative Anti Crash Absorber for a Crashworthy Landing Gear  

NASA Astrophysics Data System (ADS)

This paper defines an innovative concept to anti-crash absorber in composite material to be integrated on the landing g