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1

Multi-zone warm and cold clumpy absorbers in three Seyfert galaxies  

NASA Astrophysics Data System (ADS)

Aims: We present the first detailed X-ray analysis of three active galactic nuclei, the Seyfert 1 galaxies UGC 3142 and ESO 140-43, and the Seyfert 2 galaxy ESO 383-18, to study the geometry and the physical characteristics of their absorbers. Methods: High-quality XMM-Newton EPIC and RGS data were analyzed as well as Swift/XRT and BAT and INTEGRAL IBIS/ISGRI data to cover the 0.3-110 keV energy range. For ESO 140-43 also XMM-Newton/OM and Swift/UVOT data were used. We studied the variability of the three AGN on a time-scale of seconds using the EPIC/PN light curves, and the long-term time-scale variability of ESO 140-43 using two observations performed six months apart by XMM-Newton. Results: The spectra of the three Seyfert galaxies present a “soft excess” at energies E < 2 keV above a power law continuum that can be modeled by complex absorption, without any additional emission component. The X-ray sources in UGC 3142 and ESO 383-18 are absorbed by two layers of neutral material, with covering fractions f1 ? 0.92 and f2 ? 0.57 for UGC 3142, and f1 ? 0.97 and f2 ? 0.86 for ESO 383-18. While the clumpy absorber could be part of a disk wind or of the broad line region for UGC 3142, for ESO 383-18 a clumpy torus plus Compton thin dust lanes are more likely. The spectra of ESO 140-43 can be well fitted with a power law absorbed by three clumpy ionized absorbers with different covering factors, column densities, and ionization parameters, likely part of a moving clumpy system, which could be a disk wind or the broad line region. The strong spectral and flux variability on a time-scale of six months seen in ESO 140-43 is likely due to changes in the moving absorbers. We were able to detect the variation of the covering factor of one of the three ionized absorbers on a kilo-seconds time-scale in the EPIC light-curve of ESO 140-43.

Ricci, C.; Beckmann, V.; Audard, M.; Courvoisier, T. J.-L.

2010-07-01

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

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

NASA Astrophysics Data System (ADS)

We present analytical approximations for calculating the scattering, absorption, and escape of nonionizing photons from a spherically symmetric two-phase clumpy medium, with either a central point source of isotropic radiation, a uniform distribution of isotropic emitters, or uniformly illuminated by external sources. The analytical approximations are based on the mega-grains model of two-phase clumpy media, as proposed by Hobson & Padman, combined with escape and absorption probability formulae for homogeneous media. The accuracy of the approximations is examined by comparison with three-dimensional Monte Carlo simulations of radiative transfer, including multiple scattering. Our studies show that the combined mega-grains and escape/absorption probability formulae provide a good approximation of the escaping and absorbed radiation fractions for a wide range of parameters characterizing the clumpiness and optical properties of the medium. A realistic test of the analytic approximations is performed by modeling the absorption of a starlike source of radiation by interstellar dust in a clumpy medium and by calculating the resulting equilibrium dust temperatures and infrared emission spectrum of both the clumps and the interclump medium. In particular, we find that the temperature of dust in clumps is lower than in the interclump medium if the clumps are optically thick at wavelengths at which most of the absorption occurs. Comparison with Monte Carlo simulations of radiative transfer in the same environment shows that the analytic model yields a good approximation of dust temperatures and the emerging UV-FIR spectrum of radiation for all three types of source distributions mentioned above. Our analytical model provides a numerically expedient way to estimate radiative transfer in a variety of interstellar conditions and can be applied to a wide range of astrophysical environments, from clumpy star-forming regions to starburst galaxies.

Városi, Frank; Dwek, Eli

1999-09-01

4

Search for cold gas in strong Mg II absorbers at 0.5 < z < 1.5: nature and evolution of 21-cm absorbers  

NASA Astrophysics Data System (ADS)

We report four new detections of 21-cm absorption from a systematic search of 21-cm absorption in a sample of 17 strong (rest equivalent width, Wr(Mg ii?2796) ? 1 Å) intervening Mg ii absorbers at 0.5 < zabs < 1.5. We also present 20-cm milliarcsecond scale maps of 40 quasars having 42 intervening strong Mg ii absorbers for which we have searched for 21-cm absorption. These maps are used to understand the dependence of 21-cm detection rate on the radio morphology of the background quasar and address the issues related to the covering factor of absorbing gas. Combining 21-cm absorption measurements for 50 strong Mg ii systems from our surveys with the measurements from literature, we obtain a sample of 85 strong Mg ii absorbers at 0.5 < zabs < 1 and 1.1 < zabs < 1.5. We present detailed analysis of this 21-cm absorption sample, taking into account the effect of the varying 21-cm optical depth sensitivity and covering factor associated with the different quasar sight lines. We find that the 21-cm detection rate is higher towards the quasars with flat or inverted spectral index at cm wavelengths. About 70% of 21-cm detections are towards the quasars with linear size, LS < 100 pc. The 21-cm absorption lines having velocity widths, ?V > 100 km s-1 are mainly seen towards the quasars with extended radio morphology at arcsecond scales. However, we do not find any correlation between the integrated 21-cm optical depth, ??dv, or the width of 21-cm absorption line, ?V, with the LS measured from the milliarcsecond scale images. All this can be understood if the absorbing gas is patchy with a typical correlation length of ~30-100 pc. We confirm our previous finding that the 21-cm detection rate for a given optical depth threshold can be increased by up to a factor 2 by imposing the following additional constraints: Mg ii doublet ratio < 1.1, W(Mg ii)/W(Fe ii) < 1.47 and W(Mg i)/W(Mg ii) > 0.27. This suggests that the probability of detecting 21-cm absorption is higher in the systems with high N(H i). We show that within the measurement uncertainty, the 21-cm detection rate in strong Mg ii systems is constant over 0.5 < zabs < 1.5, i.e., over ~30% of the total age of universe. We show that the detection rate can be underestimated by up to a factor 2 if 21-cm optical depths are not corrected for the partial coverage estimated using milliarcsecond scale maps. Since stellar feedback processes are expected to diminish the filling factor of cold neutral medium over 0.5 < z < 1, this lack of evolution in the 21-cm detection rate in strong Mg ii absorbers is intriguing. Large blind surveys of 21-cm absorption lines with the upcoming Square Kilometre Array pathfinders will provide a complete view of the evolution of cold gas in galaxies and shed light on the nature ofMg ii systems and DLAs, and their relationship with stellar feedback processes. Table 4 and appendices are available in electronic form at http://www.aanda.org

Gupta, N.; Srianand, R.; Petitjean, P.; Bergeron, J.; Noterdaeme, P.; Muzahid, S.

2012-08-01

5

Clumpy Outflows from Supercritical Accretion Flow  

NASA Astrophysics Data System (ADS)

A significant amount of matter in supercritical (or super-Eddington) accretion flow is blown away by radiation force, thus forming outflows; however, the properties of such radiation-driven outflows have been poorly understood. We have performed global two-dimensional radiaion-magnetohydrodynamic simulations of supercritical accretion flow onto a black hole with 10 or 108 M? in a large simulation box of 514 rS × 514 rS (with rS being the Schwarzschild radius). We confirm that uncollimated outflows with velocities of 10 percent of the speed of light emerge from the innermost part of the accretion flow at a wide angle of 10° -50° from the disk rotation axis. Importantly, the outflows exhibit clumpy structures above heights of ˜ 250 rS. The typical size of the clumps is ˜ 10 rS , which corresponds to one optical depth, and their shapes are slightly elongated along the outflow direction. Since clumps start to form in the layer above which the (upward) radiation is superior in force to the (downward) gravity, the Rayleigh-Taylor instability seems to be a primary cause. In addition, a radiation-hydrodynamic instability, which arises when radiation funnels through a radiation-pressure-supported atmosphere, may also help to form clumps of one optical depth. A magnetic photon bubble instability does not seem to be essential, since a similar clumpy outflow structure is obtained in nonmagnetic radiation-hydrodynamic simulations. Since the spatial covering factor of the clumps is estimated to be ˜ 0.3, and since they are marginally optically thick, they will explain at least some of the rapid light variations of active galactic nuclei. We further discuss a possibility of producing broad-line region clouds by the clumpy outflow.

Takeuchi, Shun; Ohsuga, Ken; Mineshige, Shin

2013-08-01

6

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

7

Observational Constraints on Clumpiness in Supernova Ejecta  

NASA Astrophysics Data System (ADS)

Observations of polarization in supernovae (SNe) at early times have indicated the presence of asymmetries that vary in both magnitude and orientation for different elements in the ejecta. One explanation for these observations is local chemical inhomogeneities ("clumps") in the ejecta above the region which forms the continuum. To understand the effects of clumpiness on spectropolarimetric observations, we have used a fast, flexible, approximate semi-analytic code for modeling polarized line radiative transfer within three-dimensional inhomogeneous rapidly expanding atmospheres to model a wide range of clump parameter space. The results of the model make predictions that constrain the size and number of clumps that could lead to a given polarimetric signature. This talk will present a test of the model and the resulting predictions for VLT spectropolarimetric observations of SN2006X. This project was funded by the National Science Foundation grant AST-0807664 and through the Research Experiences for Undergraduates (REU) program grant NSF AST-1004872.

Tabetha Hole, K.; Boom, C.

2011-01-01

8

The clumpiness of molecular clouds: HCO+ (3-2) survey near Herbig-Haro objects  

NASA Astrophysics Data System (ADS)

Context. Some well-studied Herbig Haro objects have one or more cold, dense and quiescent clumps of gas associated with them. We propose that such clumps near an HH object can be used as a general measure of clumpiness in the molecular cloud that contains that HH object. Aims: Our aim is to survey clumps around a sample of HH objects and to use the results to estimate the clumpiness in molecular clouds. Methods: All known cold, dense and quiescent clumps near HH objects are anomalously strong HCO+ emitters. Our method is, therefore, to search for strong HCO+ emission as an indicator of a clump near an HH object. The searches were made using JCMT (for Northern hemisphere objects) and SEST (for Southern hemisphere objects) in the HCO+ (3-2) and also (for SEST observations) H13CO+ (1-0) lines, with some additional searches for methanol and sulphur monoxide lines. The selected sources were a sample of 22 HH objects in which no previous HCO+ emission had been detected. Results: We find that half of the HH objects have clumps detected in the HCO+ (3-2) line and that all searches in H13CO+ 1-0 lines show evidence of clumpiness. All condensations have narrow linewidths and are evidently unaffected dynamically by the HH jet shock. Conclusions: We conclude that the molecular clouds in which these HH objects are found must be highly heterogeneous on scales of less than 0.1 pc. An approximate calculation based on these results suggests that the area filling factor of clumps affected by HH objects is of ~10%. These clumps have gas number densities of ?3×10^4 cm-2.

Whyatt, W.; Girart, J. M.; Viti, S.; Estalella, R.; Williams, D. A.

2010-02-01

9

SPECTROPOLARIMETRIC SIGNATURES OF CLUMPY SUPERNOVA EJECTA  

SciTech Connect

Polarization has been detected at early times for all types of supernovae (SNe), indicating that all such systems result from or quickly develop some form of asymmetry. In addition, the detection of strong line polarization in SNe is suggestive of chemical inhomogeneities ('clumps') in the layers above the photosphere, which may reflect hydrodynamical instabilities during the explosion. We have developed a fast, flexible, approximate semi-analytic code for modeling polarized line radiative transfer within three-dimensional inhomogeneous rapidly expanding atmospheres. Given a range of model parameters, the code generates random sets of clumps in the expanding ejecta and calculates the emergent line profile and Stokes parameters for each configuration. The ensemble of these configurations represents the effects both of various host geometries and of different viewing angles. We present results for the first part of our survey of model geometries, specifically the effects of the number and size of clumps (and the related effect of filling factor) on the emergent spectrum and Stokes parameters. Our simulations show that random clumpiness can produce line polarization in the range observed in SNe Ia, as well as the Q-U loops that are frequently seen in all SNe. We have also developed a method to connect the results of our simulations to robust observational parameters such as maximum polarization and polarized equivalent width in the line. Our models, in connection with spectropolarimetric observations, can constrain the three-dimensional structure of SN ejecta and offer important insight into the SN explosion physics and the nature of their progenitor systems.

Hole, K. T.; Nordsieck, K. H. [Astronomy Department, University of Wisconsin-Madison, Madison, WI 53706 (United States); Kasen, D. [Department of Physics, University of California, Berkeley and Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States)

2010-09-10

10

First Statistical Tests for Clumpy Torii Models: Constraints from RXTE Monitoring of Seyfert AGN  

NASA Astrophysics Data System (ADS)

We present an analysis of multi-timescale variability in line of sight X-ray absorbing gas as a function of optical classification in Seyfert AGN in order to derive the first statistical constraints for clumpy absorbing torus models. We use the vast archive of Rossi X-ray Timing Explorer monitoring of dozens of Sy 1-1.5s and Compton-thin Sy 1.9-2s, containing sustained monitoring campaigns spanning from days to over a decade for individual objects and totaling over 220 "object×years."We search for discrete absorption events due to clouds of full-covering, neutral or mildly-ionized gas with columns approx. 1022-24 cm-2 transiting the line of sight. Using hardness ratio and photon index light curves and time-resolved spectroscopy, we confirm 11 occultation events in eight objects, including three previously published events. Peak column densities span 2.5-19 x 1022 cm-2, i.e., there are no full-covering Compton-thick events in our sample. Event durations span from 1 day to 6 months. We infer the absorbers' radial distances from the black hole, assuming Keplerian motion, to be roughly commensurate with the locations of IR-emitting dusty torii in three objects. In five objects, the X-ray clumps' locations span radii commensurate with the outer portions of optical/near-IR Broad Line Regions (BLR) outside the BLR by up to factors of 2-3. In one object, the X-ray clump is commensurate with the BLR. We discuss implications for cloud distributions in the general context of clumpy torus models and we calculate probabilities for observing obscuration in a given optical class.

Markowitz, Alex; Krumpe, M.; Nikutta, R.

2013-04-01

11

Massive Black Hole Pairs in Clumpy, Self-gravitating Circumnuclear Disks: Stochastic Orbital Decay  

NASA Astrophysics Data System (ADS)

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 •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 •2 with massive clumps M 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 •2/M 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; Colpi, Monica

2013-11-01

12

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

13

Spectral Line and Continuum Radiation Propagation in a Clumpy Medium  

NASA Astrophysics Data System (ADS)

We discuss the propagation of spectral line and continuum radiation in a clumpy medium and give general expressions for the observed absorption or emission from a cloud population. We show that the affect of the medium clumpiness can usually be characterised by a single number multiplying the mean column opacity. Our result provides a simpler proof and generalization of the result of Martin et al. (1984). The formalism provides a simple way to understand the effects of clumping on molecular line profiles and ratios; for example, how clumping effects the interpretation of 13CO(1-0) to 12CO(1-0) line ratios. It also can be used as a propagation operator in physical models of clumpy media where the incident radiation effects the spectral line emissivity. We are working to extend the formalism to the propagation of masers in a clumpy medium, but in this case, there are special difficulties because formal expectation values are not characteristic of observations because they are biased by rare events.

Conway, John; Elitzur, Moshe; Parra, Rodrigo

2005-01-01

14

Spectral Line and Continuum Radiation Propagation in a Clumpy Medium  

NASA Astrophysics Data System (ADS)

We discuss the propagation of spectral line and continuum radiation in a clumpy medium and give general expressions for the observed absorption or emission from a cloud population. We show that the affect of the medium clumpiness can usually be characterized by a single number multiplying the mean column opacity. Our result provides a simpler proof and generalization of the result of Martin et al. (1984). The formalism provides a simple way to understand the effects of clumping on molecular line profiles and ratios; for example, how clumping effects the interpretation of 13CO(1-0) to 12CO(1-0) line ratios. It also can be used as a propagation operator in physical models of clumpy media where the incident radiation effects the spectral line emissivity. We are working to extend the formalism to the propagation of masers in a clumpy medium, but in this case, there are special difficulties because formal expectation values are not characteristic of observations because they are biased by rare events.

Conway, John; Elitzur, Moshe; Parra, Rodrigo

15

Constraining clumpy dusty torus models using optimized filter sets  

NASA Astrophysics Data System (ADS)

Recent success in explaining several properties of the dusty torus around the central engine of active galactic nuclei has been gathered with the assumption of clumpiness. The properties of such clumpy dusty tori can be inferred by analysing spectral energy distributions (SEDs), sometimes with scarce sampling given that large aperture telescopes and long integration times are needed to get good spatial resolution and signal. We aim at using the information already present in the data and the assumption of clumpy dusty torus, in particular, the CLUMPY models of Nenkova et al., to evaluate the optimum next observation such that we maximize the constraining power of the new observed photometric point. To this end, we use the existing and barely applied idea of Bayesian adaptive exploration, a mixture of Bayesian inference, prediction and decision theories. The result is that the new photometric filter we use is the one that maximizes the expected utility, which we approximate with the entropy of the predictive distribution. In other words, we have to sample where there is larger variability in the SEDs compatible with the data with what we know of the model parameters. We show that Bayesian adaptive exploration can be used to suggest new observations, and ultimately optimal filter sets, to better constrain the parameters of the clumpy dusty torus models. In general, we find that the region between 10 and 200 ?m produces the largest increase in the expected utility, although sub-mm data from Atacama Large Millimeter Array also prove to be useful. It is important to note that here we are not considering the angular resolution of the data, which is key when constraining torus parameters. Therefore, the expected utilities derived from this methodology must be weighted with the spatial resolution of the data.

Asensio Ramos, A.; Ramos Almeida, C.

2013-01-01

16

Competition drives clumpy species coexistence in estuarine phytoplankton.  

PubMed

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

2013-01-08

17

Kinematic imprint of clumpy disk formation on halo objects  

NASA Astrophysics Data System (ADS)

Context. Clumpy disk galaxies in the distant universe, at redshift of z ? 1, have been observed to host several giant clumps in their disks. They are thought to correspond to early formative stages of disk galaxies. On the other hand, halo objects, such as old globular clusters and halo stars, are likely to consist of the oldest stars in a galaxy (age ? 10 Gyr), clumpy disk formation can thus be presumed to take place in a pre-existing halo system. Aims: Giant clumps orbit in the same direction in a premature disk and are so massive that they may be expected to interact gravitationally with halo objects and exercise influence on the kinematic state of the halo. Accordingly, I scrutinize the possibility that the clumps leave a kinematic imprint of the clumpy disk formation on a halo system. Methods: I perform a restricted N-body calculation with a toy model to study the kinematic influence on a halo by orbital motions of clumps and the dependence of the results on masses (mass loss), number, and orbital radii of the clumps. Results: I show that halo objects can catch clump motions and acquire disky rotation in a dynamical friction time scale of the clumps, ~0.5 Gyr. The influence of clumps is limited within a region around the disk, while the halo system shows vertical gradients of net rotation velocity and orbital eccentricity. The significance of the kinematic influence strongly depends on the clump masses; the lower limit of postulated clump mass would be ~5 × 108 M?. The result also depends on whether the clumps are subjected to rapid mass loss or not, which is an open question under debate in recent studies. The existence of such massive clumps is not unrealistic. I therefore suggest that the imprints of past clumpy disk formation could remain in current galactic halos.

Inoue, Shigeki

2013-02-01

18

Non-LTE radiative transfer in clumpy molecular clouds  

Microsoft Academic Search

We present some results of the simulation of radiative transfer in clumpy molecular clouds. For this study we have developed a program that can be used to calculate the observed molecular line profiles with one-, two- and three-dimensional model clouds. The three-dimensional models enable us to study the effect of small-scale density fluctuations on the observed molecular emission lines. The

M. Juvela

1997-01-01

19

THE INFRARED NUCLEAR EMISSION OF SEYFERT GALAXIES ON PARSEC SCALES: TESTING THE CLUMPY TORUS MODELS  

SciTech Connect

We present subarcsecond resolution mid-infrared (mid-IR) photometry in the wavelength range from 8 to 20 {mu}m of 18 Seyfert galaxies, reporting high spatial resolution nuclear fluxes for the entire sample. We construct spectral energy distributions (SEDs) that the active galactic nucleus (AGN) dominates, relatively uncontaminated by starlight, adding near-IR measurements from the literature at similar angular resolution. We find that the IR SEDs of intermediate-type Seyferts are flatter and present higher 10 to 18 {mu}m ratios than those of Seyfert 2 galaxies. We fit the individual SEDs with clumpy dusty torus models using the in-house-developed BayesClumpy tool. We find that the clumpy models reproduce the high spatial resolution measurements. Regardless of the Seyfert type, even with high spatial resolution data, near- to mid-IR SED fitting poorly constrains the radial extent of the torus. For the Seyfert 2 galaxies, we find that edge-on geometries are more probable than face-on views, with a number of clouds along equatorial rays of N{sub 0} = 5-15. The 10 {mu}m silicate feature is generally modeled in shallow absorption. For the intermediate-type Seyferts, N{sub 0} and the inclination angle of the torus are lower than those of the Seyfert 2 nuclei, with the silicate feature appearing in weak emission or absent. The columns of material responsible for the X-ray absorption are larger than those inferred from the model fits for most of the galaxies, which is consistent with X-ray absorbing gas being located within the dust sublimation radius, whereas the mid-IR flux arises from an area farther from the accretion disk. The fits yield both the bolometric luminosity of the intrinsic AGN and the torus-integrated luminosity, from which we derive the reprocessing efficiency of the torus. In the models, the outer radial extent of the torus scales with the AGN luminosity, and we find the tori to be confined to scales less than 5 pc.

Ramos Almeida, C.; Rodriguez Espinosa, J. M.; Asensio Ramos, A. [Instituto de Astrofisica de Canarias (IAC), C/Via Lactea, s/n, E-38205, La Laguna, Tenerife (Spain); Levenson, N. A. [Department of Physics and Astronomy, University of Kentucky, Lexington, KY 40506 (United States); Alonso-Herrero, A. [Instituto de Estructura de la Materia, CSIC, E-28006 Madrid (Spain); Radomski, J. T. [Gemini South Observatory, Casilla 603, La Serena (Chile); Packham, C.; Telesco, C. M. [Astronomy Department, University of Florida, 211 Bryant Space Science Center, P.O. Box 112055, Gainesville, FL 32611-2055 (United States); Fisher, R. S. [Gemini Observatory, Northern Operations Center, 670 North Aohoku Place, Hilo, HI 96720 (United States)], E-mail: cra@iac.es

2009-09-10

20

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

SciTech Connect

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

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

2009-08-10

21

Dust properties of clumpy disc galaxies at z ˜ 1.3 with Herschel-SPIRE  

NASA Astrophysics Data System (ADS)

We present the far-infrared-derived dust properties from Herschel Spectral and Photometric Imaging Receiver of the WiggleZ kinematic sample of 13 star-forming galaxies at z ˜ 1.3, with existing ancillary ˜kpc resolution integral field spectroscopy. We detect three galaxies individually and place limits on the remainder by stacking. The detected galaxies, two clumpy discs and one merger have cold dust temperatures of Td ˜ 26 K and have infrared luminosities of LIR ˜ 1.2 × 1012 L?, determined by modified blackbody fitting. The two detected disc galaxies have the largest H? surface areas of the sample and have the reddest ultraviolet-to-near-infrared spectral energy distributions. The likely source of the infrared luminosity in these objects is dust heated by the interstellar radiation field and young stellar emission from the clumps within the discs. The source of infrared luminosity for the merger is likely dust heated by a starburst resulting from the merger. The WiggleZ detections are among the coldest and lowest luminosity individual objects detected in the far-infrared at z > 1. When combining the kinematic data, we find that none of the compact galaxies nor the `dispersion-dominated' galaxies of the WiggleZ kinematic sample are detected, implying that they have warmer dust temperatures. The compact objects show the highest H? velocity dispersions in the sample, in qualitative agreement with bulge formation models. These far-infrared results strengthen the interpretation that the majority of galaxies in this sample constitute different stages in clumpy disc formation as presented from ancillary kinematic analysis.

Wisnioski, Emily; Glazebrook, Karl; Blake, Chris; Swinbank, A. Mark

2013-11-01

22

Dust properties of clumpy disc galaxies at z ˜ 1.3 with Herschel-SPIRE?  

NASA Astrophysics Data System (ADS)

We present the far-infrared-derived dust properties from Herschel Spectral and Photometric Imaging Receiver of the WiggleZ kinematic sample of 13 star-forming galaxies at z ˜ 1.3, with existing ancillary ˜kpc resolution integral field spectroscopy. We detect three galaxies individually and place limits on the remainder by stacking. The detected galaxies, two clumpy discs and one merger have cold dust temperatures of Td ˜ 26 K and have infrared luminosities of LIR ˜ 1.2 × 1012 L?, determined by modified blackbody fitting. The two detected disc galaxies have the largest H? surface areas of the sample and have the reddest ultraviolet-to-near-infrared spectral energy distributions. The likely source of the infrared luminosity in these objects is dust heated by the interstellar radiation field and young stellar emission from the clumps within the discs. The source of infrared luminosity for the merger is likely dust heated by a starburst resulting from the merger. The WiggleZ detections are among the coldest and lowest luminosity individual objects detected in the far-infrared at z > 1. When combining the kinematic data, we find that none of the compact galaxies nor the `dispersion-dominated' galaxies of the WiggleZ kinematic sample are detected, implying that they have warmer dust temperatures. The compact objects show the highest H? velocity dispersions in the sample, in qualitative agreement with bulge formation models. These far-infrared results strengthen the interpretation that the majority of galaxies in this sample constitute different stages in clumpy disc formation as presented from ancillary kinematic analysis.

Wisnioski, Emily; Glazebrook, Karl; Blake, Chris; Swinbank, A. Mark

2013-09-01

23

U3 snoRNP associates with fibrillarin a component of the scleroderma clumpy nucleolar domain.  

PubMed

Serum from patients with scleroderma recognizes the clumpy autoantigen. The present studies addressed the issue as to whether the clumpy nucleolar autoantigen recognized by scleroderma serum is fibrillarin-U3 snoRNP. Clones encoding for clumpy autoantigen were immunodetected from a lambdagt11 HeLa cell random-primed library with the serum from a patient with diffuse scleroderma and autoautoantibodies against clumpy autoantigen. Sequences from the recombinant phages were amplified by PCR and subcloned into a pCRII vector. The DNA was sequenced by a dideoxy termination reaction. Ten lambdagt11 clumpy clones were detected by immunoscreening. One containing the glycine-rich and RNP2 fibrillarin domains was expressed in lysogenic bacteria. The recombinant proteins were used to elicit antibodies in rabbits, and these exhibited clumpy nucleolar reactivity. The recombinant fibrillarin tested by ELISA was recognized by the clumpy scleroderma serum from the majority of patients. In situ hybridization assays showed that the fibrillarin tagged by the elicited antibodies was colocalized with U3 snoRNP in the nucleolus in a clumpy manner and coprecipitated the U3 snoRNP. In conclusion, the fibrillarin-U3 snoRNP complex is the major component of the clumpy subcellular domain. Therefore these molecules constitute an important target of scleroderma autoantibodies. PMID:12373336

Herrera-Esparza, Rafael; Kruse, Lars; von Essen, Marina; Campos, Lourdes; Barbosa, Olga; Bollain, Juan-José; Badillo, Isaías; Avalos-Díaz, Esperanza

2002-09-05

24

AGN Dusty Tori: II. Observational Implications of Clumpiness  

Microsoft Academic Search

From extensive radiative transfer calculations we find that clumpy torus\\u000amodels with \\\\No \\\\about 5--15 dusty clouds along radial equatorial rays\\u000asuccessfully explain AGN infrared observations. The dust has standard Galactic\\u000acomposition, with individual cloud optical depth \\\\tV \\\\about 30--100 at visual.\\u000aThe models naturally explain the observed behavior of the 10\\\\mic silicate\\u000afeature, in particular the lack of deep

Maia Nenkova; Matthew M. Sirocky; Robert Nikutta; IVEZI ´ C; Moshe Elitzur

2008-01-01

25

Supersonic flow through clumpy environments: simulations and experiments  

NASA Astrophysics Data System (ADS)

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

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

2009-11-01

26

Blue-shifted oxygen lines and the clumpy ejecta of supernova 1993J  

NASA Astrophysics Data System (ADS)

MASSIVE stars that explode at the end of their lives (type II super-novae) have been generally thought to do so rather isotropically, but there have been very few near enough to our Galaxy to study in reasonable detail. Supernova 1993J, in the nearby galaxy M81, is the second-closest supernova since the invention of the telescope, which enables us to study its early evolution. Here we report the detection of blue-shifted oxygen lines only four months after the optical discovery of the supernova. Unlike the case of SN1987A (refs 1, 2), we suggest that this blue shift is not the result of dust formation, but probably arises because the photosphere of the supernova developed a complex, irregular structure near maximum light. The clumpy ejecta allows photons from oxygen on the near (blue-shifted) side of the photosphere, which would not be visible if the ejecta were smooth and isotropic, to escape and be detected, while the photons on the far (red-shifted) side of the supernova are still absorbed. This situation arises because of mixing of regions of different element groups3,4, and clearly shows the importance of instabilities during the supernova explosion.

Wang, Lifan; Hu, Jingyao

1994-06-01

27

Observational constraints from supernovae Ia and gamma-ray bursts on a clumpy universe  

NASA Astrophysics Data System (ADS)

The luminosity distance describing the effect of local inhomogeneities in the propagation of light proposed by Zeldovich, Kantowski, Dyer, and Roeder is tested with two probes for two distinct ranges of redshifts: supernovae Ia in 0.015?z?1.414 and gamma-ray bursts in 1.547?z?3.57. Our analysis is performed by a Markov chain Monte Carlo code that allows us to constrain the matter density parameter ?m as well as the smoothness parameter ? that measures the inhomogeneous-homogeneous rate of the cosmic fluid in a flat ? cold dark matter model. The obtained best fits are ?m=0.285-0.018+0.019, ?=0.856-0.176+0.106 from supernovae Ia, and ?m=0.259-0.028+0.028, ?=0.587-0.202+0.201 from gamma-ray bursts, while from the joint analysis the best fits are ?m=0.284-0.020+0.021, ?=0.685-0.171+0.164 with ?red2=0.975. The value of the smoothness parameter ? indicates a clumped universe; however, it does not have an impact on the amount of dark energy (cosmological constant) needed to fit the observations. This result may be an indication that the Dyer-Roeder approximation does not describe in a precise form the effects of clumpiness in the expansion of the Universe.

Bretón, Nora; Montiel, Ariadna

2013-03-01

28

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.

2013-10-01

29

Polarization of Dust Emission in Clumpy Molecular Clouds and Cores  

NASA Astrophysics Data System (ADS)

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 submillimeter and far-infrared polarization, we have computed the polarization due to alignment via radiative torques within clumpy models of cores and molecular clouds. Our models were based on a highly inhomogeneous simulation of compressible MHD turbulence. A reverse Monte Carlo radiative transfer method was used to calculate the intensity and anisotropy of the internal radiation field, and the subsequent grain alignment was computed for a power-law size distribution of grains using the DDSCAT package for radiative torques. The intensity and anisotropy of the intracloud radiation field show large variations throughout the models but are generally sufficient to drive widespread grain alignment. 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 cutoff 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 models and among dust grains of different sizes, the assumption of isothermality among the aligned grains does not introduce a significant error. Our calculations indicate that submillimeter polarization vectors can be reasonably good tracers for the underlying magnetic field structure, even for relatively dense clouds (AV~10 to the cloud center). The current predictive power of the grain alignment theory should motivate future polarization observations using the next generation of multiwavelength submillimeter polarimeters such as those proposed for SOFIA.

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

2007-07-01

30

Three-dimensional Models of Embedded High-Mass Stars: Effects of a Clumpy Circumstellar Medium  

NASA Astrophysics Data System (ADS)

We use three-dimensional 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 three-dimensional clumpy and one-dimensional smooth models that 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 one-dimensional models. The near- and mid-infrared SED of the same object can vary significantly with viewing angle, depending on the clump geometry along the sight line. Even the wavelength-integrated flux can vary with angle by more than a factor of 2. 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 them to observations of some ultracompact H II regions and find that three-dimensional 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?, -1.0

Indebetouw, R.; Whitney, B. A.; Johnson, K. E.; Wood, K.

2006-01-01

31

Laboratory experiments of supersonic flows through clumpy environments  

NASA Astrophysics Data System (ADS)

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

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

2010-11-01

32

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

Microsoft Academic Search

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

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

2008-01-01

33

Gas Infall Toward Sgr A* from the Clumpy Circumnuclear Disk  

NASA Astrophysics Data System (ADS)

We present the first large-scale mosaic performed with the Submillimeter Array in the Galactic center. We have produced a 25 pointing mosaic, covering a ~2' × 2' area around Sgr A*. We have detected emission from two high-density molecular tracers, HCN(4-3) and CS(7-6), the latter never before reported in this region. The data have an angular resolution of 4farcs6 × 3farcs1, and the spectral window coverage is from -180 km s-1 to 1490 km s-1 for HCN(4-3) and from -1605 km s-1 to 129 km s-1 for CS(7-6). Both molecular tracers present a very clumpy distribution along the circumnuclear disk (CND), and are detected with a high signal-to-noise ratio in the southern part of the CND, while they are weaker toward the northern part. Assuming that the clumps are as close to the Galactic center as their projected distances, they are still dense enough to be gravitationally stable against the tidal shear produced by the supermassive black hole. Therefore, the CND is a nontransient structure. This geometrical distribution of both tracers suggests that the southern part of the CND is denser than the northern part. Also, by comparing the HCN(4-3) results with HCN(1-0) results we can see that the northern and the southern parts of the CND have different excitation levels, with the southern part warmer than the northern. Finally, we compare our results with those obtained with the detection of NH3, which traces the warmer and less dense material detected in the inner cavity of the CND. We suggest that we are detecting the origin point where a portion of the CND becomes destabilized and approaches the dynamical center of the Milky Way, possibly being impacted by the southern streamer and heated on its way inward.

Montero-Castaño, María; Herrnstein, Robeson M.; Ho, Paul T. P.

2009-04-01

34

Gravitational quenching in massive galaxies and clusters by clumpy accretion  

NASA Astrophysics Data System (ADS)

We consider a simple gravitational heating mechanism for the long-term quenching of cooling flows and star formation in massive dark matter haloes hosting elliptical galaxies and clusters. We showed earlier that the virial shock heating in haloes >=1012Msolar triggers natural quenching in 1012-1013Msolar haloes. Our present analytic estimates and simple simulations argue that the long-term quenching in haloes >=Mmin ~ 7 × 1012Msolar could be due to the gravitational energy of cosmological accretion delivered to the inner halo hot gas by cold flows via ram-pressure drag and local shocks. Mmin is obtained by comparing the gravitational power of infall into the potential well with the overall radiative cooling rate. The heating wins if the gas inner density cusp is not steeper than r-0.5 and if the masses in the cold and hot phases are comparable. The effect is stronger at higher redshifts, making the maintenance easier also at later times. Particular energy carriers into the halo core are cold gas clumps of ~105-108Msolar. Clumps >=105Msolar penetrate to the inner halo with sufficient kinetic energy before they disintegrate, but they have to be <=108Msolar for the drag to do enough work in a Hubble time. Pressure-confined ~104K clumps are stable against their own gravity and remain gaseous once below the Bonnor-Ebert mass ~108Msolar. Such clumps are also immune to tidal disruption. Clumps in the desired mass range could emerge by thermal instability in the outer halo or in the filaments that feed it if the conductivity is not too high. Alternatively, such clumps may be embedded in dark matter subhaloes if the ionizing flux is ineffective, but they separate from their subhaloes by ram pressure before entering the inner halo. Heating by dynamical friction becomes dominant for massive satellites, which can contribute up to one-third of the total gravitational heating. We conclude that gravitational heating by cosmological accretion is a viable alternative to active galactic nucleus feedback as a long-term quenching mechanism.

Dekel, Avishai; Birnboim, Yuval

2008-01-01

35

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.

Museum, Kohl C.

2012-01-01

36

A Monte-Carlo method for simulating linear polarization variations in clumpy massive-star winds  

NASA Astrophysics Data System (ADS)

I present a Monte-Carlo method for simulating the time-varying linear continuum polarization arising from electron scattering in clumpy winds, with a particular focus on massive stars. The method uses a novel semi-analytic approach to inverting the optical depth equation. Comparison against a single-scattering method reveals the latter over-predicts the mean polarization of optically thick winds, even when individual clumps are optically thin; therefore, single-scattering methods in general should be avoided when interpreting polarimetry of such winds.

Townsend, Rich

2012-05-01

37

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.

38

Searching for AGN Signatures in HST WFC3/IR Grism Spectra of Clumpy Galaxies at 0.5 < z < 2  

NASA Astrophysics Data System (ADS)

The recent discovery of a "clumpy” galaxy with three actively growing black holes in separate clumps at z = 1.35 raises the possibility of supermassive black holes (SMBHs) forming in situ within gas clouds at later epochs than previously expected. We carry out a systematic search for 0.5 < z < 2 galaxies containing multiple active galactic nuclei (AGN) by examining clumpy galaxies with Hubble Space Telescope WFC3/IR grism survey data. We select our sample of clumpy galaxies using SExtractor and galaxy classifications from the Hubble Zoo citizen science project. We then analyze the grism data of individual clumps within each galaxy to characterize the probability of SMBHs forming and growing in the clumps of forming disk galaxies at 0.5 < z < 2.

Han, Anna; Schawinski, K.; Simmons, B. D.; Urry, C. M.; Glikman, E.; Bamford, S.; Lintott, C.

2012-01-01

39

Introducing CLUMPY:. a public code for gamma-ray emission from Dark Matter annihilation in the Galaxy  

NASA Astrophysics Data System (ADS)

We present CLUMPY, a public semi-analytic code that calculates the ?-ray emission from dark matter annihilation in a variety of configurations. CLUMPY is written in C/C++ , interfaced with ROOT and is fully documented using the Doxygen package. It can be used in a statistical skymap mode or in a object-specific way. The former usage will be useful, among other things, to test the sensitivity of future ?-ray experiments, while the latter is dedicated to the study of dwarf spheroidal galaxies.

Combet, C.; Charbonnier, A.; Maurin, D.

2011-06-01

40

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

Konicek-Moran, Richard

2008-04-01

41

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

42

3D Kinematics of a z˜1.3 Lensed Clumpy Galaxy  

NASA Astrophysics Data System (ADS)

The study of the physical properties of high-redshift galaxies has become one of the major goals of extragalactic astronomy. In particular the mass-assembly histories of galaxies have been the focus of many studies at redshifts 1 to 3. The study of lensed galaxies allows to probe a low mass regime of galaxies not accessible in standard observation. Indeed, the natural magnification due to massive galaxy clusters allows to spatially resolve and constrain the dynamics of young star forming galaxies 1 to 3 magnitudes fainter than those selected in blank fields. In the purpose of probing the dynamics of intermediate and high-redshift galaxies, we have designed a research program to carry out a near-infrared spectroscopic follow up of spatially resolved distant galaxies. Here, we present the results of the 3D kinematics of a z˜1.3 “clumpy” galaxy discovered as an arc behind the lens cluster Abell 370 (z = 0.374) observed with SINFONI/VLT.

Lemoine-Busserolle, M.; Sánchez, S. F.; Kissler-Patig, M.; Pelló, R.; Bunker, A.; Kneib, J.-P.

2013-10-01

43

Laboratory experiments to study supersonic astrophysical flows interacting with clumpy environments  

NASA Astrophysics Data System (ADS)

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

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

2009-08-01

44

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 ...

45

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

46

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

47

Internal dynamics of Abell 2254: a merging galaxy cluster with a clumpy, diffuse radio emission  

NASA Astrophysics Data System (ADS)

Context. The mechanisms giving rise to diffuse radio emission in galaxy clusters and, in particular, their connection with cluster mergers are still being debated. Aims: We explore the internal dynamics of Abell 2254, which has been shown to host a very clumpy and irregular radio halo. Methods: Our analysis is mainly based on redshift data for 128 galaxies acquired at the Telescopio Nazionale Galileo. We combined galaxy velocities and positions to select 110 cluster galaxies and analyze its internal dynamics. We also used new (g', r', i') photometric data acquired at the Isaac Newton Telescope, and (V, i') photometric data available in the Subaru Archive. X-ray data from the XMM-Newton Science Archive were analyzed to study the hot gas component. Results: We estimate the cluster redshift ?z? = 0.177, a high line-of-sight (LOS) velocity dispersion, ?V 1350 km s-1, and the X-ray temperature kT 6.4 keV. Both our optical and X-ray analyses reveal complex dynamical activity. The analysis of the 2D galaxy distribution reveals the presence of two density peaks, one to the east and the other to the west (E and W peaks). Using the full 3D information we detect a high-velocity (?Vrf,LOS 3000 km s-1), low-mass (?V 200-500 km s-1) group at the position of the 2D E peak. For the main system we compute a velocity dispersion ?V 1000-1200 km s-1. In the assumption of a bimodal system we estimate a mass Msys = 1.5-2.9 × 1015 h70-1 M_{?}. The X-ray morphological analysis, which is based on power ratios, centroid shifts, and concentration parameter, confirms that Abell 2254 is a dynamically disturbed cluster. The X-ray isophotes are elongated in the east direction, in agreement with a merger in the post core-crossing phase. A simple bimodal model finds that data are consistent with a bound, outgoing subcluster observed a few fractions of Gyr after the core crossing. However, both optical and X-ray analyses suggest that the main system is, in turn, a nonrelaxed structure, indicating north-south as a possible direction for a past accretion. Conclusions: We conclude that Abell 2254, for its mass and merging structure, fits well among the typical clusters with radio halos. We briefly discuss how the particular irregularity of the radio halo might be linked to the complexity of the Abell 2254 structure.

Girardi, M.; Bardelli, S.; Barrena, R.; Boschin, W.; Gastaldello, F.; Nonino, M.

2011-12-01

48

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.

2007-12-12

49

Common cold  

MedlinePLUS

... C for preventing and treating the common cold. Cochrane Database of Systematic Reviews 2007, Issue 3. Art. ... M, Das RR. Zinc for the common cold. Cochrane Database of Systematic Reviews 2011, Issue 2. Art. ...

50

Drill string shock absorber  

Microsoft Academic Search

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

E. A. Anderson; D. D. Webb

1985-01-01

51

Smooth and clumpy dust distributions in AGN: a direct comparison of two commonly explored infrared emission models  

NASA Astrophysics Data System (ADS)

The geometry of dust distribution within the inner regions of active galactic nuclei (AGN) is still a debated issue and relates directly to the AGN unified scheme. Traditionally, models discussed in the literature assume one of the two distinct dust distributions in what is believed to be a toroidal region around the supermassive black holes: a continuous distribution, customarily referred to as smooth, and a concentration of dust in clumps or clouds, referred to as clumpy. In this paper we perform a thorough comparison between two of the most popular models in the literature, namely the smooth models by Fritz et al. and the clumpy models by Nenkova et al., in their common parameter space. Particular attention is paid to the silicate features at ˜9.7 and ˜18 ?m, the width of the infrared bump, the near-infrared index and the luminosity at 12.3 ?m, all previously reported as possible diagnostic tools to distinguish between the two dust distributions. We find that, due to different dust chemical compositions used in the two models, the behaviour of the silicate features at 9.7 and 18 ?m is quite distinct between the two models. The width of the infrared bump and the peak of the infrared emission can take comparable values; their distributions do, however, vary. The near-infrared index is also quite different, due partly to the primary sources adopted by the two models. Models with matched parameters do not produce similar spectral energy distributions (SEDs) and virtually no random parameter combinations can result in seemingly identical SEDs.

Feltre, A.; Hatziminaoglou, E.; Fritz, J.; Franceschini, A.

2012-10-01

52

Methods for absorbing neutrons  

SciTech Connect

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

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

2012-07-24

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.

Industry, Oregon M.

1997-01-01

54

Cold injuries.  

PubMed

There are two categories of cold injury. The first is hypothermia, which is a systemic injury to cold, and the second is frostbite, which is a local injury. Throughout history, entire armies, from George Washington to the Germans on the Russian Front in World War II, have fallen prey to prolonged cold exposure. Cold injury is common and can occur in all seasons if ambient temperature is lower than the core body temperature. In the 1985 Boston Marathon, even though it was 76 degrees and sunny, there were 75 runners treated for hypothermia. In general, humans adapt poorly to cold exposure. Children are at particular risk because of their relatively greater surface area/body mass ratio, causing them to cool even more rapidly than adults. Because of this, the human's best defense against cold injury is to limit his/her exposure to cold and to dress appropriately. If cold injury has occurred and is mild, often simple passive rewarming such as dry blankets and a warm room are sufficient treatment. PMID:17630517

Kruse, R J

1995-01-01

55

Cold Intolerance  

MedlinePLUS

... Professionals Excerpt from the Handbook on the Late Effects of Poliomyelitis for Physicians and Survivors © Cold Intolerance Many polio survivors report that their feet have always been cold to the touch, their skin a purplish color. As they age, their limbs become more sensitive ...

56

Heat absorbing window  

Microsoft Academic Search

A heat absorbing window is disclosed which can receive solar energy and transmit the illumination part of the solar energy, while utilizing the heat part of such energy to provide a source of heat for useful purposes. The window includes a frame with three window panes. The outermost pane faces the exterior and is of non-heat absorbing material. The middle

Berman

1978-01-01

57

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

58

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

Microsoft Academic Search

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

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

2007-01-01

59

Radar Absorbing Material Design.  

National Technical Information Service (NTIS)

Low observable platforms have extremely low radar cross section specifications that cannot be achieved by shaping alone. The application of radar absorbing material is necessary, in which case the appropriate constitutive parameters and thickness must be ...

C. K. Yuzcelik

2003-01-01

60

Review of Radar Absorbing Materials.  

National Technical Information Service (NTIS)

Radar is a sensitive detection tool and since its development, methods for reducing microwave reflections have been explored. Radar absorbers can be classified as impedance matching or resonant absorbers. Radar absorbing materials are made from resistive ...

P. Saville

2005-01-01

61

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

SciTech Connect

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

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

2009-12-10

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

COLD TRAP  

DOEpatents

An improved linear-flow cold trap is designed for highvacuum applications such as mitigating back migration of diffusion pump oil moiecules. A central pot of liquid nitrogen is nested within and supported by a surrounding, vertical, helical coil of metai sheet, all enveloped by a larger, upright, cylindrical, vacuum vessel. The vertical interstices between successive turns of the coil afford lineal, axial, high-vacuum passages between open mouths at top and bottom of said vessel, while the coil, being cold by virtue of thermal contact of its innermost turn with the nitrogen pot, affords expansive proximate condensation surfaces. (AEC)

Milleron, N.

1963-03-12

64

Mechanical energy absorber  

NASA Astrophysics Data System (ADS)

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

Wesselski, Clarence J.

1993-07-01

65

Mechanical energy absorber  

NASA Astrophysics Data System (ADS)

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

Wesselski, Clarence J.

1995-06-01

66

Cold War  

NSDL National Science Digital Library

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

67

Heat Resistant Radar Absorber.  

National Technical Information Service (NTIS)

A foamed ceramic slab is bonded to the three-layer polyimide RAM substrate to produce a radar absorbed capable of at least 10db absorptivity of the range 3 to at least 10 GHZ and of withstanding very high temperatures, for example, 3000 F for 80 seconds o...

W. P. Manning W. T. Passiuk

1978-01-01

68

Polypyrrole Based Microwave Absorbers  

Microsoft Academic Search

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

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

1998-01-01

69

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

70

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

71

Cold soybean management decision system based on JSP  

Microsoft Academic Search

In accordance with the requirements management of cold soybean growth characters integrated climatic conditions, soil fertility status of region, the laws of cold soybean absorbing nutrients, the soil nutrient supplying capacity and other various factors to set up models and rules. The system based on the object-oriented technology of JSP VB VC had some trials on middle plant part (Hailun),

Song Yihong; Yang Yushu; Li Xiao

2010-01-01

72

Solar energy absorber  

SciTech Connect

A solar energy absorber module is described comprising a molded substantially rigid top sheet of translucent plastic material and a molded substantially rigid bottom sheet of solar energy absorbing substantially opaque plastic material bonded together by circular bond indentations formed in each of the top sheet and the bottom sheet. The circular bond indentation on each sheet is spaced from each other a distance equal to the diameter of the circular bond thereby forming convex lens-like elliptical sites located between adjacent circular bond indentations for augmentation of solar energy, the circular bond indentations being formed in successive offset rows to define longitudinal tortuous sinusoidal channels in communication with a header at each end of the module for passage of working fluid therethrough.

Smith, W.F.

1988-08-16

73

COLD TRAPS  

DOEpatents

A cold trap is presented for removing a condensable component from a gas mixture by cooling. It consists of a shell, the exterior surface of which is chilled by a refrigerant, and conductive fins welded inside the shell to condense the gas, and distribute the condensate evenly throughout the length of the trap, so that the trap may function until it becomes completely filled with the condensed solid. The contents may then be removed as either a gas or as a liquid by heating the trap. This device has particuinr use as a means for removing uranium hexafluoride from the gaseous diffusion separation process during equipment breakdown and repair periods.

Thompson, W.I.

1958-09-30

74

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

75

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

76

Corrosion resistant neutron absorbing coatings  

Microsoft Academic Search

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

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

2012-01-01

77

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

SciTech Connect

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

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

2010-12-01

78

Cold Urticaria  

PubMed Central

Sera were obtained from the venous effluents of cold-challenged arms of patients with idiopathic cold urticaria without plasma or serum cryoproteins; these sera exhibited increased neutrophil chemotactic activity without alterations of the complement system. A two- to fourfold augmentation of the base-line neutrophil chemotactic activity of serum from the immersed extremity began within 1 min, peaked at 2 min, and returned to base-line levels within 15 min, whereas there was no change in the serum chemotactic activity in the control arm. The augmented chemotactic activity in the serum specimens from the challenged arm of each patient appeared in a high molecular-weight region, as assessed by the difference in activity recovered after Sephadex G-200 gel filtration of the paired lesional and control specimens. Sequential purification of this high molecular-weight activity by anion- and cation-exchange chromatography revealed a single peak of activity at both steps. The partially purified material continued to exhibit a high molecular weight, being excluded on Sepharose 4B, and had a neutral isoelectric point. The partially purified material showed a preferential chemotactic activity for neutrophilic polymorphonuclear leukocytes, required a gradient for expression of this function, and exhibited a capacity to deactivate this cell type. This active principle, termed high molecular-weight neutrophil chemotactic factor, exhibited a time-course of release that could be superimposed upon that of histamine and the low molecular-weight eosinophil chemotactic factor and may represent another mast cell-derived mediator.

Wasserman, Stephen I.; Soter, Nicholas A.; Center, David M.; Austen, K. Frank

1977-01-01

79

Absorber for solar power.  

PubMed

A simple, economical absorber utilizing a new principle of operation to achieve very low reradiation losses while generating temperatures limited by material properties of quartz is described. Its performance is analyzed and indicates approximately 90% thermal efficiency and 73% conversion efficiency for an earth based unit with moderately concentrated (~tenfold) sunlight incident. It is consequently compatible with the most economic of concentrator mirrors (stamped) or mirrors deployable in space. Space applications are particularly attractive, as temperatures significantly below 300 K are possible and permit even higher conversion efficiency. PMID:20134700

Powell, W R

1974-10-01

80

Solar radiation absorbing material  

DOEpatents

Solar energy absorbing means in solar collectors are provided by a solar selective carbon surface. A solar selective carbon surface is a microporous carbon surface having pores within the range of 0.2 to 2 micrometers. Such a surface is provided in a microporous carbon article by controlling the pore size. A thermally conductive substrate is provided with a solar selective surface by adhering an array of carbon particles in a suitable binder to the substrate, a majority of said particles having diameters within the range of about 0.2-10 microns.

Googin, John M. (Oak Ridge, TN); Schmitt, Charles R. (Oak Ridge, TN); Schreyer, James M. (Oak Ridge, TN); Whitehead, Harlan D. (Clinton, TN)

1977-01-01

81

A modular wideband sound absorber  

NASA Astrophysics Data System (ADS)

The absorption coefficients were measured of various depths of RW2 grade Rockwool laid directly on the floor of the ISO-Standard reverberation room at BBC Research Department. The Rockwool was very effective as a wideband sound absorber. A new absorber was designed and tested, having the dimensions of the existing BBC type A modular absorbers and containing RW2 Rockwool. The new absorber has a smoother absorption coefficient curve, a less complicated construction, and weighs less than the existing BBC wideband absorber (type A8/A9). It has been named type A11 and has an equivalent performance to that of BBC type A2 and A3 absorbers combined. It complements, very well, the performance of the A10 very low frequency absorber, described in a companion Report (BBC RD No. 1992/10).

Plumb, G. D.

82

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

83

Metamaterial electromagnetic wave absorbers.  

PubMed

The advent of negative index materials has spawned extensive research into metamaterials over the past decade. Metamaterials are attractive not only for their exotic electromagnetic properties, but also their promise for applications. A particular branch-the metamaterial perfect absorber (MPA)-has garnered interest due to the fact that it can achieve unity absorptivity of electromagnetic waves. Since its first experimental demonstration in 2008, the MPA has progressed significantly with designs shown across the electromagnetic spectrum, from microwave to optical. In this Progress Report we give an overview of the field and discuss a selection of examples and related applications. The ability of the MPA to exhibit extreme performance flexibility will be discussed and the theory underlying their operation and limitations will be established. Insight is given into what we can expect from this rapidly expanding field and future challenges will be addressed. PMID:22627995

Watts, Claire M; Liu, Xianliang; Padilla, Willie J

2012-05-25

84

The microwave absorbing phenomena of ferrite microwave absorbers  

Microsoft Academic Search

The complex permeability dispersions and the microwave absorbing phenomena are investigated in ferrite microwave absorbers. The complex permeability of hexagonal (Y- and Z-type) and spinel (NiZn ferrite and NiZnCo ferrite) ferrite microwave absorbers were measured in 200 MHz-16 GHz range. The theoretical matching frequencies are determined by plotting the measured complex permeability loci on the impedance matching solution map. One

J. Y. Shin; J. H. Oh

1993-01-01

85

DUSTY STRUCTURE AROUND TYPE-I ACTIVE GALACTIC NUCLEI: CLUMPY TORUS NARROW-LINE REGION AND NEAR-NUCLEUS HOT DUST  

SciTech Connect

We fitted Spitzer/IRS approx 2-35 mum spectra of 26 luminous quasi-stellar objects in an attempt to define the main emission components. Our model has three major components: a clumpy torus, dusty narrow-line region (NLR) clouds, and a blackbody-like dust. The models utilize the clumpy torus of Nenkova et al. and are the first to allow its consistent check in type-I active galactic nuclei (AGNs). Single torus models and combined torus-NLR models fail to fit the spectra of most sources, but three-component models adequately fit the spectra of all sources. We present torus inclination, cloud distribution, covering factor, and torus mass for all sources and compare them with bolometric luminosity, black hole mass, and accretion rate. The torus mass is found to be correlated with the bolometric luminosity of the sources. Torus-covering factor may also be (anti-)correlated, if some possibly anomalous points are omitted. We find that a substantial amount of the approx2-7 mum radiation originates from a hot dust component, which is likely situated in the innermost part of the torus. The luminosity radiated by this component and its covering factor are comparable to those of the torus. We quantify the emission by the NLR clouds and estimate their distance from the center. The distances are approx700 times larger than the dust sublimation radius, and the NLR-covering factor is about 0.07. The total covering factor by all components is in good agreement with the known AGN type-I:type-II ratio.

Mor, Rivay; Netzer, Hagai [School of Physics and Astronomy and the Wise Observatory, The Raymond and Beverly Sackler Faculty of Exact Sciences, Tel-Aviv University, Tel-Aviv 69978 (Israel); Elitzur, Moshe [Department of Physics and Astronomy, University of Kentucky, Lexington, KY 40506-0055 (United States)

2009-11-01

86

Facts about the Common Cold  

MedlinePLUS

... Disease > Influenza > In-Depth-Resources Facts About the Common Cold What is a Cold? Colds are minor infections ... are no antiviral medications available for treating the common cold. Antibiotics are not useful for treating a cold, ...

87

Shock Absorbers - Are They Necessary?  

Microsoft Academic Search

The economic benefits of running a shock absorber seem evident from their growing use in oil and gas drilling operations. However, some controversy still exists over when they should be used, how to get the greatest benefit from them, and whether there are some negative effects such as hole deviation associated with the usage of some shock absorbers. Extensive experience

S. W. Worford; P. G. Craig

1983-01-01

88

Shock absorbers - Are they necessary  

SciTech Connect

The economic benefits of running a shock absorber seem evident from their growing use in oil and gas drilling operations. However, some controversy still exists over when they should be used, how to get the greatest benefit from them, and whether there are some negative effects such as hole deviation associated with the usage of some shock absorbers. Extensive experience in recent years has included results with a wide variety of shock absorber designs in the full range of hole depths and sizes. The results show that lateral stiffness of the tool, the type of spring or other energy absorption system, and tool length have a significant influence on shock absorber performance. The energy absorption system and its location in the drill string, in conjunction with the type of bottom hole assembly design, bit selection, and formation characteristics, determine whether the maximum benefits possible from the shock absorber are attained. Major benefits from proper use of the appropriate shock absorber are longer bit life, higher drilling rates, longer drill-string life, reduced hazard from bending fatigue of the threaded connections in the drill string, and reduced wear on the rig equipment. These all result in a significant reduction of the overall drilling costs. Guidelines for shock absorber selection, placement in the drill string, and operating practices which yield the greatest overall benefit from the use of a shock absorber in oil field drilling are described. Ultimately, the decision to use a shock absorber will be based on economics. Does the use of a shock absorber reduce the overall drilling cost.

Worford, S.W.; Craig, P.G.

1983-02-01

89

Cold Signaling and Cold Response in Plants  

PubMed Central

Plants are constantly exposed to a variety of environmental stresses. Freezing or extremely low temperature constitutes a key factor influencing plant growth, development and crop productivity. Plants have evolved a mechanism to enhance tolerance to freezing during exposure to periods of low, but non-freezing temperatures. This phenomenon is called cold acclimation. During cold acclimation, plants develop several mechanisms to minimize potential damages caused by low temperature. Cold response is highly complex process that involves an array of physiological and biochemical modifications. Furthermore, alterations of the expression patterns of many genes, proteins and metabolites in response to cold stress have been reported. Recent studies demonstrate that post-transcriptional and post-translational regulations play a role in the regulation of cold signaling. In this review article, recent advances in cold stress signaling and tolerance are highlighted.

Miura, Kenji; Furumoto, Tsuyoshi

2013-01-01

90

Method for designing an absorbent article  

US Patent & Trademark Office Database

A method for designing an absorbent article. The steps of the method are generating a physical spatial map of saturation of a fluid within an absorbent in a physical test environment, generating a virtual spatial map of saturation of a fluid within an absorbent in a virtual test environment, identifying absorbent-fluid interaction properties for the absorbent such that the virtual spatial map of saturation approximates the physical spatial map of saturation, inputting the absorbent-fluid interaction properties into a virtual model of the absorbent article to produce a representation of at least one feature of the absorbent article, evaluating the virtual model of the absorbent article to determine the performance of the at least one feature of the absorbent article, modifying the design of the absorbent article in response to the performance of the at least one feature of the absorbent article determined from the virtual model of the absorbent article.

Allende-Blanco; Mel (Loveland, OH); Anderson; Brian Bert (Liberty Township, OH); Hartt, IV; William Handy (Mason, OH); Lipic; Paul Martin (West Chester, OH); Schmidt; Mattias (Idstein, DE); Stevens; Douglas Gregory (Blue Ash, OH); Ehrnsperger; Bruno Johannes (Evendale, OH)

2010-03-23

91

Ultrathin multiband gigahertz metamaterial absorbers  

NASA Astrophysics Data System (ADS)

We propose ultrathin multiband metamaterial absorbers in the microwave frequencies in which the design, analysis, fabrication, and measurement of the absorbers working in multiple bands are presented. The metamaterial absorbers consist of a periodic arrangement of different scales of electric-field-coupled-LC (ELC) resonators and a metallic background plane, separated by only 1 mm dielectric spacer. By tuning the scale factor of the ELC unit cells, we achieve independently multiple absorptions at different customized frequencies. Experiments demonstrate excellent absorption rates in the designed frequency bands over wide angles of incident waves for both transverse electric and magnetic polarizations. The explanation to the physical mechanism of the multiband metamaterial absorber is presented and verified.

Li, Hui; Yuan, Li Hua; Zhou, Bin; Shen, Xiao Peng; Cheng, Qiang; Cui, Tie Jun

2011-07-01

92

Ultrasensitive cold-electron bolometer  

NASA Astrophysics Data System (ADS)

The Cold-Electron Bolometer (CEB) is an ultrasensitive device designed for the detection of cosmic microwave background radiation. The key to its sensitivity is the electron cooling of the absorber by the superconductor-insulator-normal metal (SIN) tunnel junction. At a voltage near and below the superconducting gap, the electrons in the absorber are cooled well below the phonon temperature of the normal metal. This translates to the enhanced sensitivity of the CEB. This thesis describes the work we have done on the optimization of electron cooling of the normal metal absorber, and our measurement of the sensitivity of the CEB. We have optimized the electron cooling of the absorber by SIN tunnel junctions. The best electron cooling was achieved when normal metal traps were added in proximity to the superconducting electrodes in addition to the advanced geometry of the superconducting electrodes. With these modifications, we have decreased the electron temperature by 198 mK. With just the advanced geometry, the electron temperature drop was 129 mK. With just a simple geometry, the drop in temperature was 56 mK. The noise equivalent power (NEP) of the CEB was also measured at 100 mK to be at the level of 10 -18 W/Hz 1/2 at 1 kHz. The NEP was obtained by measuring the noise of the CEB, and then dividing that by its power responsivity, dV/dP. The main limitation in our measurements was the noise component from the amplifier. Finally, we have made measurements on the temperature sensitivity of the SIN tunnel junctions. We have compared the sensitivity between single and ten SIN junctions in series and found that it increases proportionally to the number of junctions. The best temperature responsivity obtained for 10 junctions was approximately 15 mV/mK. Using such thermometer, we have been able to measure the temperature stability of the Oxford Instruments cryogenfree refrigerator to be ±250 mK for a period of 8 hours. The resolution of the thermometer was measured to be ±100 mK, limited by the noise due to the amplifier. The current and future works are also discussed. These include: a CEB array designed to distribute the total power load, improving further the sensitivity; a one-thousand SIN tunnel junction series thermometer in order to realize and understand the fundamental limitation of such a device; a superconducting cold- electron bolometer (SCEB) for high background power loads; and different read- out systems including an on-chip quasiparticle amplifier (QPA).

Agulo, Ian Jasper Ayagan

2007-08-01

93

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.…

Silverthorn, Dee U.; Michael, Joel

2013-01-01

94

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

95

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.

Wilkinson, William H. (Columbus, OH)

1984-01-01

96

Skin Reactions to Cold  

PubMed Central

Although skin reactions to cold are seen surprisingly infrequently in Canada, it is important to manage them correctly when they do occur. Frostbite, cold urticarias, Raynaud's disease and phenomenon, and several miscellaneous changes are discussed.

Talpash, Orest

1976-01-01

97

Coping with Colds  

MedlinePLUS

... hanging out with someone who is smoking. And people who smoke are more likely to catch colds than people ... cold. Stay clear of smokers, too: even secondhand smoke can make people more likely to get sick. Don't use ...

98

Radiative Transfer in a Clumpy Universe. IV. New Synthesis Models of the Cosmic UV/X-Ray Background  

NASA Astrophysics Data System (ADS)

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? 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, ?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/~pmadau/CUBA.

Haardt, Francesco; Madau, Piero

2012-02-01

99

Evaluation of the Mark 11 Mod 0 UBA in Cold Water.  

National Technical Information Service (NTIS)

The MK 11 Mod 0 UBA was evaluated for its ability to efficiently absorb carbon dioxide during prolonged moderate work in cold water. In addition, thermal protection of the absorbent bed and the degree of inspired gas warming were analyzed. The results sho...

R. K. O'Bryan R. L. Clinton R. A. Vendetto

1978-01-01

100

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

101

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

102

The X-Ray Warm Absorber in NGC 3516  

NASA Astrophysics Data System (ADS)

The Seyfert 1 galaxy, NGC 3516 has been the subject of many absorption line studies at both ultraviolet and X-ray wavelengths. In the UV, strong, broad, variable associated metal line absorption with velocity width ~2000 km s-1 is thought to originate in gas with NH >~ 1019 cm-2 lying between 0.01 and 9 pc from the central active nucleus. The Ginga X-ray data are consistent with several possibilities: a warm absorber and a cold absorber combined either with partial covering or an unusually strong reflection spectrum. We present ROSAT observations of NGC 3516 which show a strong detection of a warm absorber dominated by a blend of O VII/O VIII edges at ~0.8 keV with NH ~ 7 x 1021 cm-2 and U:8--12. We argue that NGC 3516 contains an outflowing "XUV" absorber showing the presence of X-ray absorption edges which are consistent with the presence of broad absorption lines in the old IUE spectra and their disappearance in the new UV observations. Our dynamical model suggests that the O VII absorption edge will continue to weaken compared to the O VIII edge, an easily testable prediction with future missions like AXAF. Eventually the source would be transparent to the X-rays unless a new absorption system is produced.

Mathur, Smita; Wilkes, Belinda J.; Aldcroft, Thomas

1997-03-01

103

Novel planar absorber designs using genetic algorithms  

Microsoft Academic Search

Electromagnetic absorbers are often used to reduce radar echo from anechoic chambers, aircraft and so on. For many applications, the absorber must be built conformable to a complex surface, or must have a flat interface with the air. A new class of planar electromagnetic absorbers is proposed. This absorber is created by drilling textures within or on top of lossy

Suomin Cui; D. S. Weile; J. L. Volakis

2005-01-01

104

Counterflow absorber for an absorption refrigeration system  

DOEpatents

An air-cooled, vertical tube absorber for an absorption refrigeration system is disclosed. Strong absorbent solution is supplied to the top of the absorber and refrigerant vapor is supplied to the bottom of the absorber to create a direct counterflow of refrigerant vapor and absorbent solution in the absorber. The refrigeration system is designed so that the volume flow rate of refrigerant vapor in the tubes of the absorber is sufficient to create a substantially direct counterflow along the entire length of each tube in the absorber. This provides several advantages for the absorber such as higher efficiency and improved heat transfer characteristics, and allows improved purging of non-condensibles from the absorber.

Reimann, Robert C. (Lafayette, NY)

1984-01-01

105

Cranial reossification with absorbable plates.  

PubMed

The purpose of this study was to examine the effect of Lactosorb absorbable plates on bone healing across cranial bone defects in the rabbit skull. Two 10-mm diameter parietal skull defects were created in each of 20 rabbits, with one defect being placed on either side of the sagittal suture. In 10 rabbits, an absorbable plate was placed across both the inner and outer cortices of the left defect, and in the other 10 rabbits, an absorbable plate was placed across the outer cortex only of the left defect. The right defect always served as the control side, with no plate being placed across it. Rabbits were killed an average of 25 weeks postoperatively. Areas of reossification in the experimental and control defects of each rabbit were then measured, examined histologically, and compared. Growth across defects spanned by one plate was also compared with growth across defects spanned by two plates. Histologic and statistical analyses revealed no significant differences in reossification between the control and experimental defects in each animal and between the defects spanned by one versus two plates. This study suggests that these copolymer absorbable plates neither inhibit nor facilitate reossification across 10-mm diameter rabbit cranial defects. PMID:11304603

Ascherman, J; Knowles, S; Marin, V; Prisant, N; Hu, G; Chiu, D T

2001-03-01

106

Microwave absorbing composite lattice grids  

Microsoft Academic Search

Stretching dominated lattice grids reinforced by glass fibers and carbon fibers filled with spongy materials were designed and manufactured to achieve multifunctional structures with microwave absorbing abilities. The reflectivity of the GFRC and CFRC grid panels was measured in the darkroom at normal and oblique incidences, respectively. GFRC grid panels of 20mm thickness and CFRC panels of 18mm thickness displayed

H. L. Fan; W. Yang; Z. M. Chao

2007-01-01

107

How Greenhouse Gases Absorb Heat  

NSDL National Science Digital Library

Learners observe two model atmospheres -- one with normal atmospheric composition and another with an elevated concentration of carbon dioxide. These two model atmospheres are exposed to light energy from a sunny window or from a lamp. This activity will help learners understand that greenhouse gases in the atmosphere absorb and hold heat, relating to global warming and climate change.

History, American M.

2008-01-01

108

Performance Testing of Shock Absorbers  

Microsoft Academic Search

For a better understanding and evaluation of shock absorber performance, detailed data upon their relevant physical parameters, such as spring characteristics and energy dissipation properties, have been measured in a test jig. Down hole tests where well defined sinusoidal vibrations are generated in a 1000 m vertical drill string by means of a down hole exciter were also performed. The

E. Skaugen; A. Kyllingstad

1986-01-01

109

Mitochondria in the Cold  

Microsoft Academic Search

Development of hibernation strategies for cold preservation of human organs represents a far-reaching goal in transplantation surgery. Short cold storage times of <6 h tolerated by the human heart remain a major clinical problem. Mitochondrial cold storage-reperfusion injury is becoming recognized as a limiting factor in preservation of organs from non-hibernating mammals. Damaged mitochondria lead to cellular injury by reduction

110

Cold fusion: Alchemist's dream  

NASA Astrophysics Data System (ADS)

In this report the following topics relating to cold fusion are discussed: muon catalyzed cold fusion; piezonuclear fusion; sundry explanations pertaining to cold fusion; cosmic ray muon catalyzed cold fusion; vibrational mechanisms in excited states of D2 molecules; barrier penetration probabilities within the hydrogenated metal lattice/piezonuclear fusion; branching ratios of D2 fusion at low energies; fusion of deuterons into He-4; secondary D+T fusion within the hydrogenated metal lattice; helium-3 to helium-4 ratio within the metal lattice; shock induced fusion; and anomalously high isotopic ratios of helium-3/helium-4.

Clayton, E. D.

1989-09-01

111

Light-absorbing impurities in Arctic snow  

NASA Astrophysics Data System (ADS)

Absorption of radiation by ice is extremely weak at visible and near-ultraviolet wavelengths, so small amounts of light-absorbing impurities in snow can dominate the absorption of solar radiation at these wavelengths, reducing the albedo relative to that of pure snow, contributing to the surface energy budget and leading to earlier snowmelt. In this study Arctic snow is surveyed for its content of light-absorbing impurities, expanding and updating the 1983-1984 survey of Clarke and Noone. Samples were collected in Alaska, Canada, Greenland, Svalbard, Norway, Russia, and the Arctic Ocean during 1998 and 2005-2009, on tundra, glaciers, ice caps, sea ice, frozen lakes, and in boreal forests. Snow was collected mostly in spring, when the entire winter snowpack is accessible for sampling. Sampling was carried out in summer on the Greenland Ice Sheet and on the Arctic Ocean, of melting glacier snow and sea ice as well as cold snow. About 1200 snow samples have been analyzed for this study. The snow is melted and filtered; the filters are analyzed in a specially designed spectrophotometer system to infer the concentration of black carbon (BC), the fraction of absorption due to non-BC light-absorbing constituents and the absorption Ångstrom exponent of all particles. This is done using BC calibration standards having a mass absorption efficiency of 6.0 m2 g-1 at 550 nm and by making an assumption that the absorption Angstrom exponent for BC is 1.0 and for non-BC light-absorbing aerosol is 5.0. The reduction of snow albedo is primarily due to BC, but other impurities, principally brown (organic) carbon, are typically responsible for ~40% of the visible and ultraviolet absorption. The meltwater from selected snow samples was saved for chemical analysis to identify sources of the impurities. Median BC amounts in surface snow are as follows (nanograms of carbon per gram of snow): Greenland 3, Arctic Ocean snow 7, melting sea ice 8, Arctic Canada 8, subarctic Canada 14, Svalbard 13, Northern Norway 21, western Arctic Russia 27, northeastern Siberia 34. Concentrations are more variable in the European Arctic than in Arctic Canada or the Arctic Ocean, probably because of the proximity to BC sources. Individual samples of falling snow were collected on Svalbard, documenting the springtime decline of BC from March through May. Absorption Ångstrom exponents are 1.5-1.7 in Norway, Svalbard, and western Russia, 2.1-2.3 elsewhere in the Arctic, and 2.5 in Greenland. Correspondingly, the estimated contribution to absorption by non-BC constituents in these regions is ~25%, 40%, and 50% respectively. It has been hypothesized that when the snow surface layer melts some of the BC is left at the top of the snowpack rather than being carried away in meltwater. This process was observed in a few locations and would cause a positive feedback on snowmelt. The BC content of the Arctic atmosphere has declined markedly since 1989, according to the continuous measurements of near-surface air at Alert (Canada), Barrow (Alaska), and Ny-Ålesund (Svalbard). Correspondingly, the new BC concentrations for Arctic snow are somewhat lower than those reported by Clarke and Noone for 1983-1984, but because of methodological differences it is not clear that the differences are significant. Nevertheless, the BC content of Arctic snow appears to be no higher now than in 1984, so it is doubtful that BC in Arctic snow has contributed to the rapid decline of Arctic sea ice in recent years.

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

2010-12-01

112

Progress with cold antihydrogen  

Microsoft Academic Search

The creation of cold antihydrogen by the ATHENA and ATRAP collaborations, working at CERN’s unique Antiproton Decelerator (AD) facility, has ushered in a new era in atomic physics. This contribution will briefly review recent results from the ATHENA experiment. These include discussions of antiproton slowing down in a cold positron gas during antihydrogen formation, information derived on the dependence of

M. Amoretti; C. Amsler; G. Bonomi; P. D. Bowe; C. Canali; C. Carraro; C. L. Cesar; M. Charlton; M. Doser; A. Fontana; M. C. Fujiwara; R. Funakoshi; P. Genova; J. S. Hangst; R. S. Hayano; I. Johnson; L. V. Jørgensen; A. Kellerbauer; V. Lagomarsino; R. Landua; E. Lodi Rizzini; M. Macrí; N. Madsen; G. Manuzio; D. Mitchard; P. Montagna; H. Pruys; C. Regenfus; A. Rotondi; G. Testera; A. Variola; L. Venturelli; D. P. van der Werf; Y. Yamazaki; N. Zurlo

2006-01-01

113

Chilling Out with Colds  

MedlinePLUS

... in these droplets can spread a cold from one person to another. You also can catch a cold ... and watery eyes coughing feeling tired and not hungry congestion (when your nose is stuffy and it's hard to breathe) Helping Kids Feel Better Here are some feel-better ...

114

Exercise in the cold  

Microsoft Academic Search

Exercising in the cold is not an attractive option for many athletes; however, defining what represents cold is difficult and is not standard for all events. If the exercise is prolonged and undertaken at a moderate intensity, environmental temperatures around 11°C can be an advantage. If the intensity is lower than this value and the individual does not generate sufficient

Myra Nimmo

2004-01-01

115

Cold waves in Serbia  

NASA Astrophysics Data System (ADS)

Climate extreme indices allow the assessment of changes in extreme climate events. The cold Spell Duration Indice (CSDI), from which the duration and severity of the cold waves are estimated, was applied to the seasonal series of the daily minimum temperatures at 15 meteorological stations in Serbia during the period 1949 to 2012. An analysis of the daily minimum temperatures during the winter season revealed that the longest (up to 20-22 days) and most severe cold waves were recorded in 1954, 1956, 1963 and 1983. In the transient seasons, the cooling episodes were observed in 1983 and 1988 (autumn season) and in 1987 (spring season) followed with a great reduction in duration and severity of cold waves. During the summer season, only in 1962, the longest (from 6 to 8 days) and most intense cold wave was registered almost over the whole territory of Serbia.

Unkasevic, Miroslava; Tosic, Ivana

2013-04-01

116

Terahertz Backscattering Behavior of Various Absorbing Materials.  

National Technical Information Service (NTIS)

The Submillimeter-Wave Technology Laboratory (STL) at the University of Massachusetts Lowell has investigated the electromagnetic scattering behavior of various broadband absorbers. Several absorbing materials were tested in a compact radar range operatin...

A. J. Gatesman C. Wu L. DeRoeck R. H. Giles T. Horgan

2009-01-01

117

Waveguide characterization of flexible absorbing material  

Microsoft Academic Search

Among the materials with adequate performance to be used as radar absorbing material (RAM), the conducting polymers have been under intensive study due to their excellent potential for application in electromagnetic interference and microwave absorption areas, replacing conventional absorbing materials. The aim of this work is to present electromagnetic characterization of the flexible radar absorbing material at microwave frequency range

L. C. Folgueras; R. Faez; M. C. Rezende

2003-01-01

118

An introduction to Radar Absorbent Materials (RAM)  

Microsoft Academic Search

The electromagnetic principles of radar absorbent materials are summarized. The fundamental theory of electromagnetic wave propagation in media and at the interfaces between different media is reviewed, and approaches to absorber design are described. The types of materials required and the techniques for measuring their electromagnetic properties and the performance of the finished absorber are outlined. A means of designing

P. G. Lederer

1986-01-01

119

Embedded absorbers for helicopter rotor lag damping  

Microsoft Academic Search

Radial and chordwise damped vibration absorbers embedded in the rotor blade are compared for rotor lag damping augmentation. Results show that the radial absorber is more effective in transferring damping to the rotor blade lag mode. The chordwise absorber needs to be at a more outboard location and have a larger mass to introduce levels of lag damping comparable to

Lynn Byers; Farhan Gandhi

2009-01-01

120

Embedded absorbers for helicopter rotor lag damping  

NASA Astrophysics Data System (ADS)

Radial and chordwise damped vibration absorbers embedded in the rotor blade are compared for rotor lag damping augmentation. Results show that the radial absorber is more effective in transferring damping to the rotor blade lag mode. The chordwise absorber needs to be at a more outboard location and have a larger mass to introduce levels of lag damping comparable to that introduced by the radial absorber. The 1/rev amplitude of a chordwise absorber at the blade tip, per degree of blade lead-lag motion in forward flight, is of the order of 35% of the blade chord, and such a stroke might be difficult to accommodate. The 1/rev amplitude of a radial absorber at 70% span (having significantly lower mass than the chordwise absorber and producing comparable lag damping) is of the order of 4% of the rotor blade span. The static displacement of the radial absorber under centrifugal load needs to be limited using a frequency-dependent (high static stiffness, low dynamic stiffness) or nonlinear spring. The chordwise absorber can also undergo a large static displacement under the chordwise component of the centrifugal load if there is an offset from the feather axis, and this would again have to be limited using a strategy such as a frequency-dependent spring. Significant advantages of the radial absorber are—higher lag damping, lower absorber mass, space for absorber mass travel, and no chordwise travel of blade center of gravity reducing susceptibility to aeroelastic instability and dynamic pitch-link loads.

Byers, Lynn; Gandhi, Farhan

2009-09-01

121

FFTF absorber-pin performance verification test  

Microsoft Academic Search

The FFTF (Fast Flux Test Facility) Absorber Pin Performance Verification Test - (HA006) is an irradiation test of neutron absorber pins with integral temperature and pressure monitoring instrumentation. The pins, containing boron carbide, are representative of the FFTF Row 3 Safety, Row 5 Control and Row 7 Fixed Shim Absorber Assemblies. In the 300 full power days (FPD) this test

J. A. Basmajian; D. C. King; J. L. Jackson; M. A. Vogel

1982-01-01

122

Polarization Signature of AGN Warm Absorber Flows  

NASA Astrophysics Data System (ADS)

Active Galactic Nuclei (AGN), Seyfert galaxies and quasars, are powered by luminous accretion and often accompanied by winds which are powerful enough to affect the AGN mass budget, and whose observational appearance bears an imprint of processes which are happening within the central parsec around the black hole (BH). One example of such a wind is the partially ionized gas responsible for X-ray and UV absorption ('warm absorbers') observed in many AGN. Here we show that such gas will have a distinct signature when viewed in polarized X-rays. Observations of such polarization can test models for the geometry of the flow, and the gas responsible for launching and collimating it. We present calculations which show that the polarization depends on the hydrodynamics of the flow, the quantum mechanics of resonance line scattering and the transfer of polarized X-ray light in the highly ionized moving gas. The results emphasize the significance of the three dimensional nature of the wind for modeling spectra. We show that the polarization in the 0.1-10 keV energy range is dominated by the effects of resonance lines. We predict a 5 - 25% X-ray polarization signature of type-2 objects in this energy range. These results are general to flows which originate from a cold torus-like structure, located 1pc from the BH, which wraps the BH and is ultimately responsible for the apparent dichotomy between type 1 and type 2 AGNs. Such signals will be detectable by future dedicated X-ray polarimetry space missions, such as the NASA Gravity and Extreme Magnetism SMEX, "GEMS."

Dorodnitsyn, Anton; Kallman, T.

2010-02-01

123

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

124

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 compounds 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.

Iverson, Daniel C. (Aiken, SC)

1990-01-01

125

Mulitlayered Nanostructured Broad Band Absorber  

NASA Astrophysics Data System (ADS)

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

Corrigan, Timothy; Ide, Benjamin

2013-03-01

126

Light-absorbing impurities in Arctic snow  

NASA Astrophysics Data System (ADS)

Absorption of radiation by ice is extremely weak at visible and near-ultraviolet wavelengths, so small amounts of light-absorbing impurities in snow can dominate the absorption of solar radiation at these wavelengths, reducing the albedo relative to that of pure snow, contributing to the surface energy budget and leading to earlier snowmelt. In this study Arctic snow is surveyed for its content of light-absorbing impurities, expanding and updating the 1983-1984 survey of Clarke and Noone. Samples were collected in Alaska, Canada, Greenland, Svalbard, Norway, Russia, and the Arctic Ocean during 2005-2009, on tundra, glaciers, ice caps, sea ice, frozen lakes, and in boreal forests. Snow was collected mostly in spring, when the entire winter snowpack is accessible for sampling. Sampling was carried out in summer on the Greenland ice sheet and on the Arctic Ocean, of melting glacier snow and sea ice as well as cold snow. About 1200 snow samples have been analyzed for this study. The snow is melted and filtered; the filters are analyzed in a specially designed spectrophotometer system to infer the concentration of black carbon (BC), the fraction of absorption due to non-BC light-absorbing constituents and the absorption Ångstrom exponent of all particles. The reduction of snow albedo is primarily due to BC, but other impurities, principally brown (organic) carbon, are typically responsible for ~40% of the visible and ultraviolet absorption. The meltwater from selected snow samples was saved for chemical analysis to identify sources of the impurities. Median BC amounts in surface snow are as follows (nanograms of carbon per gram of snow): Greenland 3, Arctic Ocean snow 7, melting sea ice 8, Arctic Canada 8, Subarctic Canada 14, Svalbard 13, Northern Norway 21, Western Arctic Russia 26, Northeastern Siberia 17. Concentrations are more variable in the European Arctic than in Arctic Canada or the Arctic Ocean, probably because of the proximity to BC sources. Individual samples of falling snow were collected on Svalbard, documenting the springtime decline of BC from March through May. Absorption Ångstrom exponents are 1.5-1.7 in Norway, Svalbard, and Western Russia, 2.1-2.3 elsewhere in the Arctic, and 2.5 in Greenland. Correspondingly, the estimated contribution to absorption by non-BC constituents in these regions is ~25%, 40%, and 50%, respectively. It has been hypothesized that when the snow surface layer melts some of the BC is left at the top of the snowpack rather than being carried away in meltwater. This process was observed in a few locations and would cause a positive feedback on snowmelt. The BC content of the Arctic atmosphere has declined markedly since 1989, according to the continuous measurements of near-surface air at Alert (Canada), Barrow (Alaska), and Ny-Ålesund (Svalbard). Correspondingly, the new BC concentrations for Arctic snow are somewhat lower than those reported by Clarke and Noone for 1983-1984, but because of methodological differences it is not clear that the differences are significant.

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

2010-08-01

127

Febrile/cold agglutinins  

MedlinePLUS

Cold agglutinins; Weil-Felix reaction; Widal's test; Warm agglutinins; Agglutinins ... but may include: Excessive bleeding Fainting or feeling light-headed Hematoma (blood accumulating under the skin) Infection ( ...

128

Exercise in the Cold.  

National Technical Information Service (NTIS)

Humans have developed the technical capability to protect themselves, from a thermoregulation point of view, against almost any terrestrial extreme. With respect to the extreme cold, it is understood that the best technique to ensure survival resides in e...

A. L. Vallerand

1995-01-01

129

Cold Sores (Herpes)  

MedlinePLUS Videos and Cool Tools

... Unfortunately, the cold sore virus usually hides in nerve cells. This makes it impossible for antibodies to totally kill the virus. The virus “sleeps” in the nerve cells. While “asleep,” the virus is called dormant. When ...

130

Cold plasma dispersion surfaces  

Microsoft Academic Search

Following the work of Stringer (1963), this study presents three-dimensional plots of dispersion in a cold anisotropic plasma. The omega(k, theta) surfaces (where k is the wave vector for a fixed angle of propagation) provide a clear picture of the behavior of cold plasma waves as the direction of propagation is varied. The group velocity (dw\\/dk) has a simple geometrical

M. E. Oakes; R. B. Michie; K. H. Tsui; J. E. Copeland

1979-01-01

131

Transmission of colds  

Microsoft Academic Search

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

Diane E. Pappas; J. Owen Hendley

132

Exercise in the cold.  

PubMed

Exercising in the cold is not an attractive option for many athletes; however, defining what represents cold is difficult and is not standard for all events. If the exercise is prolonged and undertaken at a moderate intensity, environmental temperatures around 11 degrees C can be an advantage. If the intensity is lower than this value and the individual does not generate sufficient metabolic heat to offset the effects imposed by the cold environment, then temperatures of 11 degrees C can be detrimental to performance. Similarly, when the performance involves dynamic explosive contractions, then a Cold ambient temperature can have a negative influence. Additional factors such as the exercising medium, air or water, and the anthropometric characteristics of the athlete will also make a difference to the strategies that can be adopted to offset any negative impact of a cold environment on performance. To plan for a performance in the cold requires an understanding of the mechanisms underpinning the physiological response. This review attempts to outline these mechanisms and how they can be manipulated to optimize performance. PMID:15768724

Nimmo, Myra

2004-10-01

133

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

134

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

135

Clumpy disc and bulge formation  

NASA Astrophysics Data System (ADS)

We present a set of hydrodynamical/N-body controlled simulations of isolated gas-rich galaxies that self-consistently include supernova (SN) feedback and a detailed chemical evolution model, both tested in cosmological simulations. The initial conditions are motivated by the observed star-forming galaxies at z ˜ 2-3. We find that the presence of a multiphase interstellar media in our models promotes the growth of disc instability favouring the formation of clumps which, in general, are not easily disrupted on time-scales compared to the migration time. We show that stellar clumps migrate towards the central region and contribute to form a classical-like bulge with a Sérsic index, n > 2. Our physically motivated SN feedback has a mild influence on clump survival and evolution, partially limiting the mass growth of clumps as the energy released per SN event is increased, with the consequent flattening of the bulge profile. This regulation does not prevent the building of a classical-like bulge even for the most energetic feedback tested. Our SN feedback model is able to establish self-regulated star formation, producing mass-loaded outflows and stellar age spreads comparable to observations. We find that the bulge formation by clumps may coexist with other channels of bulge assembly such as bars and mergers. Our results suggest that galactic bulges could be interpreted as composite systems with structural components and stellar populations storing archaeological information of the dynamical history of their galaxy.

Perez, Josefa; Valenzuela, Octavio; Tissera, Patricia B.; Michel-Dansac, Leo

2013-09-01

136

Clumpy disc and bulge formation  

NASA Astrophysics Data System (ADS)

We present a set of hydrodynamical/N-body controlled simulations of isolated gas-rich galaxies that self-consistently include supernova (SN) feedback and a detailed chemical evolution model, both tested in cosmological simulations. The initial conditions are motivated by the observed star-forming galaxies at z ˜ 2-3. We find that the presence of a multiphase interstellar media in our models promotes the growth of disc instability favouring the formation of clumps which, in general, are not easily disrupted on time-scales compared to the migration time. We show that stellar clumps migrate towards the central region and contribute to form a classical-like bulge with a Sérsic index, n > 2. Our physically motivated SN feedback has a mild influence on clump survival and evolution, partially limiting the mass growth of clumps as the energy released per SN event is increased, with the consequent flattening of the bulge profile. This regulation does not prevent the building of a classical-like bulge even for the most energetic feedback tested. Our SN feedback model is able to establish self-regulated star formation, producing mass-loaded outflows and stellar age spreads comparable to observations. We find that the bulge formation by clumps may coexist with other channels of bulge assembly such as bars and mergers. Our results suggest that galactic bulges could be interpreted as composite systems with structural components and stellar populations storing archaeological information of the dynamical history of their galaxy.

Perez, Josefa; Valenzuela, Octavio; Tissera, Patricia B.; Michel-Dansac, Leo

2013-11-01

137

Liquid crystal tunable metamaterial absorber.  

PubMed

We present an experimental demonstration of electronically tunable metamaterial absorbers in the terahertz regime. By incorporation of active liquid crystal into strategic locations within the metamaterial unit cell, we are able to modify the absorption by 30% at 2.62 THz, as well as tune the resonant absorption over 4% in bandwidth. Numerical full-wave simulations match well to experiments and clarify the underlying mechanism, i.e., a simultaneous tuning of both the electric and magnetic response that allows for the preservation of the resonant absorption. These results show that fundamental light interactions of surfaces can be dynamically controlled by all-electronic means and provide a path forward for realization of novel applications. PMID:23679774

Shrekenhamer, David; Chen, Wen-Chen; Padilla, Willie J

2013-04-25

138

Quality improvement of Pleurotus mushrooms by modified atmosphere packaging and moisture absorbers  

Microsoft Academic Search

Quality of Pleurotusostreatus mushrooms was compared during cold storage under various temperatures and modified atmospheres with and without moisture absorbers. CO2 production followed a non-climacteric pattern and was about 0.50, 0.99 and 1.23 ?mol CO2 kg?1 s?1 at 0, 4 and 7°C, respectively, after 12 h. At the end of 11 days of storage, the respiration rates were very similar

R Villaescusa; M. I Gil

2003-01-01

139

ANL Advanced Photon Source crotch absorber design  

Microsoft Academic Search

The ANL 7 GeV Advanced Photon Source storage ring crotch absorber will be subjected to a very high photon loading power density, approximately 750 w\\/mm2 at normal incidence. To accommodate this high heat load, two designs are studied: a V-type compound angle absorber and a horizontally rotated plate absorber. For both model, thermal and structural analyses have been carried out

M. Choi; J. D. Gonczy; J. W. Howell; R. C. Niemann

1991-01-01

140

Cold Regions Bibliography  

NSDL National Science Digital Library

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

141

Hexaferrite contribution to microwave absorbers characteristics  

NASA Astrophysics Data System (ADS)

The influence is studied of Co-Ti substituted Ba hexaferrite on the efficiency of the hexaferrite-magnetite-graphite triple absorbing system of fillers dispersed in a rubber matrix. Using the planned experiment technique, the optimal ratio is determined of its components, as well as their influence on the absorber's optimal thickness. The introduction of a hexaferrite in the system improves the composite absorbing properties manifested mostly in broadening the maximal absorption frequency band. It is assumed that the presence of the hexaferrite results in improving the long-range order of the absorbing fillers arrangement in the polymer matrix.

Dishovski, N.; Petkov, A.; Nedkov,, IV; Razkazov,, IV

1994-03-01

142

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

143

Crazy Cold Air  

NSDL National Science Digital Library

This activity has students record the temperatures in and around a walk-in refrigerator or freezer to see how cold air behaves when it meets warmer air. The printable five-page handout includes a series of inquiry-based questions to get students thinking about how the temperature of air changes its density, detailed experiment directions, and a worksheet that helps students use experimental results to obtain insight into the wind patterns of Antarctica. They will observe why cold air rushes out of a freezer when you open the door and how it then moves through a room. Through this experiment the students gain insight into the blustery winds of Antarctica.

144

The broad band X-ray spectra of Seyfert 2s: constraining the geometry of the absorber in AGN  

NASA Astrophysics Data System (ADS)

The unified model of AGN foresees that different types of Seyfert galaxies are intrinsically the same object, and that observational differences are solely due to different inclination angles with respect to an obscuring toroidal structure. However, recent results have shown that the anisotropic absorber appear to be clumpy and to have covering factors inversely proportional to the luminosity, and that some objects classified as Seyfert 2s intrinsically lack the broad line region. The hard X-rays (>10 keV) are a very suitable energy band for studying the unified model. In fact, absorption does not play an important role at these energies, allowing to have a direct look at the central engine of the AGN. In a recent paper (Ricci et al. 2011) we found, by analyzing the INTEGRAL IBIS/ISGRI average hard X-ray spectra of ˜200 Seyfert galaxies, that while Seyfert 1s and Seyfert 2s have the same continuum emission, Seyfert 2s have a significantly larger reflection component, which cannot be easily explained by the unified model, but might require an intrinsic difference in the average covering factor of the torus between Seyfert 1s and Seyfert 2s. I will present a study of the broad band X-ray (0.3-200 keV) spectra of ˜100 hard X-ray selected Seyfert 2s, using XMM-Newton, Suzaku, INTEGRAL, Swift and Chandra data. The work is aimed at understanding the results found in Ricci et al. (2011), and at constraining the structure of the reflecting/absorbing medium, applying phenomenological models and, for the first time on a large sample, the physical torus models recently developed by Ikeda et al. (2009) and Murphy and Yaqoob (2009). I will also discuss the results of recent simulations we performed, aimed at explaining the X-ray Baldwin effect with the receding torus model.

Ricci, Claudio; Paltani, Stephane

2012-07-01

145

Device for absorbing mechanical shock  

DOEpatents

This invention is a comparatively inexpensive but efficient shock-absorbing device having special application to the protection of shipping and storage cylinders. In a typical application, two of the devices are strapped to a cylinder to serve as saddle-type supports for the cylinder during storage and to protect the cylinder in the event it is dropped during lifting or lowering operations. In its preferred form, the invention includes a hardwood plank whose grain runs in the longitudinal direction. The basal portion of the plank is of solid cross-section, whereas the upper face of the plank is cut away to form a concave surface fittable against the sidewall of a storage cylinder. The concave surface is divided into a series of segments by transversely extending, throughgoing relief slots. A layer of elastomeric material is positioned on the concave face, the elastomer being extrudable into slots when pressed against the segments by a preselected pressure characteristic of a high-energy impact. The compressive, tensile, and shear properties of the hardwood and the elastomer are utilized in combination to provide a surprisingly high energy-absorption capability.

Newlon, Charles E. (Knoxville, TN)

1980-01-01

146

Device for absorbing mechanical shock  

SciTech Connect

This invention is a comparatively inexpensive but efficient shock-absorbing device having special application to the protection of shipping and storage cylinders. In a typical application, two of the devices are strapped to a cylinder to serve as saddle-type supports for the cylinder during storage and to protect the cylinder in the event it is dropped during lifting or lowering operations. In its preferred form, the invention includes a hardwood plank whose grain runs in the longitudinal direction. The basal portion of the plank is of solid cross-section, whereas the upper face of the plank is cut away to form a concave surface fittable against the sidewall of a storage cylinder. The concave surface is divided into a series of segments by transversely extending, throughgoing relief slots. A layer of elastomeric material is positioned on the concave face, the elastomer being extrudable into slots when pressed against the segments by a preselected pressure characteristic of a high-energy impact. The compressive, tensile, and shear properties of the hardwood and the elastomer are utilized in combination to provide a surprisingly high energy -absorption capability.

Newlon, C.E.

1980-12-30

147

Device for absorbing mechanical shock  

DOEpatents

This invention is a comparatively inexpensive but efficient shock-absorbing device having special application to the protection of shipping and storage cylinders. In a typical application, two of the devices are strapped to a cylinder to serve as saddle-type supports for the cylinder during storage and to protect the cylinder in the event it is dropped during lifting or lowering operations. In its preferred form, the invention includes a hardwood plank whose grain runs in the longitudinal direction. The basal portion of the plank is of solid cross-section, whereas the upper face of the plank is cut away to form a concave surface fittable against the sidewall of a storage cylinder. The concave surface is divided into a series of segments by transversely extending, throughgoing relief slots. A layer of elastomeric material is positioned on the concave face, the elastomer being extrudable into slots when pressed against the segments by a preselected pressure characteristic of a high-energy impact. The compressive, tensile, and shear properties of the hardwood and the elastomer are utilized in combination to provide a surprisingly high energy-absorption capability.

Newlon, C.E.

1979-08-29

148

Koldstartsanalyse. (Cold start analysis).  

National Technical Information Service (NTIS)

During the period in which a petrol-driven private car is driven with a cold engine, it uses a richer petrol/air mixture in order to overcome carburation difficulties in the inlet manifold. This results in higher emission. With or without catalytic conver...

H. C. Thorsen H. Bendtsen

1994-01-01

149

Hot Talk, Cold Science  

Microsoft Academic Search

One of the hottest topics in climate science is understanding and evaluating the impacts of possible global warming caused by anthropogenic emissions of greenhouse gases. In Hot Talk, Cold Science, S. Fred Singer does not accept global warming. Singer says in his preface, ``The purpose of this book is to demonstrate that the evidence [for global warming] is neither settled,

Robert J. Oglesby

1998-01-01

150

Recent Cold War Studies  

ERIC Educational Resources Information Center

|Cold War historiography has undergone major changes since the 1991 collapse of the Soviet Union. For two years (1992-1993) the principal Soviet archives fell open to scholars, and although some of the richest holdings are now once again closed, new information continues to find its way out. Moreover, critical documentary information has become…

Pineo, Ronn

2003-01-01

151

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

152

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.

Tugel, Joyce; Keeley, Page

2009-03-01

153

The cold reading technique.  

PubMed

For many people, belief in the paranormal derives from personal experience of face-to-face interviews with astrologers, palm readers, aura and Tarot readers, and spirit mediums. These encounters typically involve cold reading, a process in which a reader makes calculated guesses about a client's background and problems and, depending on the reaction, elaborates a reading which seems to the client so uniquely appropriate that it carries with it the illusion of having been produced by paranormal means. The cold reading process is shown to depend initially on the Barnum effect, the tendency for people to embrace generalized personality descriptions as idiosyncratically their own. Psychological research into the Barnum effect is critically reviewed, and uses of the effect by a professional magician are described. This is followed by detailed analysis of the cold reading performances of a spirit medium. Future research should investigate the degree to which cold readers may have convinced themselves that they actually possess psychic or paranormal abilities. PMID:3360083

Dutton, D L

1988-04-15

154

The cold reading technique  

Microsoft Academic Search

Summary For many people, belief in the paranormal derives from personal experience of face-to-face interviews with astrologers, palm readers, aura and Tarot readers, and spirit mediums. These encounters typically involve cold reading, a process in which a reader makes calculated guesses about a client's background and problems and, depending on the reaction, elaborates a reading which seems to the client

D. L. Dutton

1988-01-01

155

Cold war thaws  

Microsoft Academic Search

The cold war on energy conservation seems to be thawing in the nation's capitol. After a decade of relentless attacks on energy conservation research and development budgets that left them 75% below their high water mark, the US Congress is embracing energy conservation as a vital ally. The authors describe all the current proposals in both the House and Senate

Totten

2009-01-01

156

Cold-Weather Sports  

MedlinePLUS

... Your Cool in the Cold and Snow Bad-Weather Driving Contact Us Print Additional resources Send to a friend Reprint guidelines Share this page using: What are these? Note: Clicking these links will take you to a site outside of KidsHealth's control.

157

The design of broadband radar absorbing surfaces  

Microsoft Academic Search

There has been a growing and widespread interest in radar absorbing material technology. As the name implies, radar absorbing materials or RAM's are coatings whose electric and magnetic properties have been selected to allow the absorption of microwave energy at discrete or broadband frequencies. In military applications low radar cross section (RCS) of a vehicle may be required in order

Go H. Suk

1990-01-01

158

Wideband thin resistive metamaterial radar absorbing screen  

Microsoft Academic Search

It has been demonstrated that two layer metamaterial Hilbert curve array constructed from low conductivity material can act as a thin wideband radar absorbing screen. The advantage of using Hilbert curve over traditional circuit analogue radar absorbing screen is the smaller unit cell size, resulting in reduced coupling to higher order Floquent modes and reduced diffraction effects, which in turn

A. Noor; Zhirun Hu; H. H. Ouslimani; A. Priou

2009-01-01

159

Modelling of magnetic radar absorbing composites  

Microsoft Academic Search

This paper addresses the modelling of radar absorbing composite layers with ferromagnetic inclusions. The radar absorbing properties of these layers are strongly determined by the effective permeability of the composite material. The applicability of mixing formulas is discussed to determine the effective permeability. Furthermore, the RF-frequency behaviour of ferromagnetic inclusions is described. The mixing formulas and the RF-frequency behaviour of

Harmen Schippers; Tomas Lundin; Jaap Heijstek

2010-01-01

160

Terahertz backscattering behavior of various absorbing materials  

Microsoft Academic Search

The Submillimeter-Wave Technology Laboratory (STL) at the University of Massachusetts Lowell has investigated the electromagnetic scattering behavior of various broadband absorbers. Several absorbing materials were tested in a compact radar range operating at a center frequency of 160 GHz. The polarimetric radar cross section was measured at elevation angles from 15° to 75°. In addition to the backscattering behavior, the

C. Wu; A. J. Gatesman; L. Deroeck; T. Horgan; R. H. Giles; W. E. Nixon

2009-01-01

161

Orally Ingested Heparin Is Absorbed in, Humans  

Microsoft Academic Search

It has been accepted for many years that orally ingested heparin is not absorbed. Recent evidence has shown that heparin placed in the stomach of rats is very rapidly absorbed and that it also quickly and almost completely attaches to the vascular endothelium and prevents jugular vein thrombosis. Within 6 min, heparin was undetectable in the blood plasma. If a

Hyman Engelberg

1995-01-01

162

Evaluation of commercial fuel tank water absorbers  

NASA Astrophysics Data System (ADS)

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, William R.

1994-11-01

163

Gas absorber and refrigeration system using same  

Microsoft Academic Search

A refrigeration system is described comprising: (a) a separator for separating a refrigerant gas from a refrigerant-rich solution to produce a refrigerant-lean solution; (b) a condenser for emitting heat to thereby condense the refrigerant gas received from the separator and an evaporator for absorbing heat to thereby evaporate the condensed refrigerant gas; (c) an absorber assembly including: a precooler for

Dehne

1993-01-01

164

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

165

Cold Injury of Amputated Digits.  

National Technical Information Service (NTIS)

Patients who acquired an upper extremity nerve injury often complain about cold intolerance, reduced sensitivity and decreased task performance. This study tried to quantify these complaints and look in more detail at the thermal reaction to local cold ex...

U. Ahcan B. Luzar F. Bajrovic I. Mekjavic

2005-01-01

166

Cold Weather and Cardiovascular Disease  

MedlinePLUS

Cold Weather and Cardiovascular Disease Updated:Dec 11,2012 The fall and winter seasons will bring cooler temperatures, and ... and snow. It’s important to know how cold weather can affect your heart, especially if you have ...

167

Stay Safe in Cold Weather!  

MedlinePLUS

... Health and Aging » Publications Stay Safe in Cold Weather! What is hypothermia? Keep warm inside Bundle up ... to find more information Stay Safe in Cold Weather! Learn Why You Need to Stay Warm When ...

168

Prototype Cold Weather Face Mask.  

National Technical Information Service (NTIS)

An improved cold weather face mask has been developed which should provide protection from cold, wind, blowing snow, and frostbite in environments to -65F and 35 mph wind velocities. The mask provides physical compatibility with military clothing and equi...

D. Mangelsdorf M. Goldberg R. Colman S. Tobey

1971-01-01

169

Remedies for Common Cold Symptoms  

PubMed Central

Individuals suffering from intolerable symptoms of the common cold can now be advised of safe and effective products for symptomatic relief. This article describes and discusses four categories of drugs used to treat the common cold. To simplify the product selection process for family physicians, suggestions are included for possible ingredients for treatments of specific cold symptoms.

Miller, Penny F.

1991-01-01

170

COLD WAR CULTURE AND RELIGION  

Microsoft Academic Search

In this course, we will adopt a different focus. We will emphasize the cultural processes through which people in the United States participated in, and came to understand, the cold war as a way of life. (This course deals with cold war culture and religion only in the U.S.) During the cold war, American citizens struggled to construct a \\

Ira Chernus

171

Cold Drawn ERW Pipes with Superior Formability,  

National Technical Information Service (NTIS)

Cold drawn ERW pipes have been applied in various fields. Cold drawn pipes show recrystallized microstructures when they are annealed for softening. Cold drawn ERW pipes sometimes show a difficulty in formability during cold working of expanding, swaging ...

T. Adaniya T. Takamura T. Meada F. Nishimura M. Morimoto

1988-01-01

172

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

173

WISPy cold dark matter  

NASA Astrophysics Data System (ADS)

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; Cadamuro, Davide; Goodsell, Mark; Jaeckel, Joerg; Redondo, Javier; Ringwald, Andreas

2012-06-01

174

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

2012-06-26

175

Antioxidant power quantification of decoction and cold infusions of Hibiscus sabdariffa flowers  

Microsoft Academic Search

In this paper the overall antioxidant power, expressed as Briggs–Rauscher antioxidant index, of decoction or cold infusions of dried Hibiscus sabdariffa flowers was determined at 25 and 37°C, to compare the scavenger ability of the beverages at either room or physiological temperature. Total polyphenol contents and the absorbance of anthocyanin pigments were also determined, and the trend with the overall

Enrico Prenesti; Silvia Berto; Pier G. Daniele; Simona Toso

2007-01-01

176

Study of the thermal behavior of a latent heat cold storage unit operating under frosting conditions  

Microsoft Academic Search

A study is performed of the thermal behavior of a latent heat cold storage unit operating under frosting conditions. This unit is employed to maintain the temperature inside the refrigerated compartment of a truck below 265 K. The system consists of parallel plates filled with a phase change material (PCM) that absorbs heat from the flow of warm moist air.

A. P. Simard; M. Lacroix

2003-01-01

177

Conformal metamaterial absorber for curved surface.  

PubMed

In this paper, three different unit cells are designed on the basis split-ring-cross resonators, and each unit cell has an absorption rate greater than 90% at incident angles of 0°, 30°, and 45°, respectively. They are non-periodically placed in three different zones on the curved surface. Therefore, the proposed conformal metamaterial absorber can achieve a high absorption rate. The performance of the proposed absorber is compared with that of a metallic curved surface and a conformal metamaterial absorber with the same unit cells. PMID:24104326

Jang, Youngsoo; Yoo, Minyeong; Lim, Sungjoon

2013-10-01

178

Cold denaturation of ubiquitin  

Microsoft Academic Search

Temperature induced unfolding of bovine ubiquitin in solutions with different concentrations of guanidinium hydrochloride (GdmCl) has been measured using differential scanning calorimetry. It has been shown that at high concentrations of GdmCl the ubiquitin molecule can undergo both heat and cold induced denaturation. Analysis of the enthalpy of unfolding of ubiquitin in the presence of GdmCl shows a good agreement

Beatriz Ibarra-Molero; George I. Makhatadze; Jose M. Sanchez-Ruiz

1999-01-01

179

Cold Front Characteristics  

NSDL National Science Digital Library

In this activity, students will study animations of several atmospheric variables (air temperature, dew point, solar radiation, rainfall, and wind) to investigate the characteristics of weather produced by a cold front passage. Working in small groups, they will view animations from two different cases, identify patterns and changes, and answer questions about what they see. Links to a student worksheet, to the animations, and to viewing software are provided.

180

Crazy Cold Air  

NSDL National Science Digital Library

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

181

Cold nuclear fusion  

SciTech Connect

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

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

2012-02-15

182

The X-ray warm absorber and nuclear obscuration in the Seyfert 1.8 galaxy ESO 113-G010  

NASA Astrophysics Data System (ADS)

We present the first analysis of the X-ray warm absorber and nuclear obscuration in the Seyfert 1.8 galaxy ESO 113-G010. We used archival data from a 100 ks XMM-Newtonobservation made in 2005. From high resolution spectroscopy analysis of the RGS data, we detect absorption lines originating from a warm absorber consisting of two distinct phases of ionisation, with log ? ? 3.2 and 2.3 respectively. The higher-ionised component has a larger column density and outflow velocity (NH ? 1.6 × 1022 cm-2, v ? - 1100 km s-1) than the lower-ionised component (NH ? 0.5 × 1022 cm-2, v ? -700 km s-1). The shape of the optical-UV continuum and the large Balmer decrement (H?/H? ~ 8) indicate significant amount of reddening is taking place in our line of sight in the host galaxy of the AGN; however, the X-ray spectrum is not absorbed by cold neutral gas intrinsic to the source. We discuss different explanations for this discrepancy between the reddening and the X-ray absorption, and suggest that the most likely solution is a dusty warm absorber. We show that dust can exist in the lower-ionised phase of the warm absorber, which causes the observed reddening of the optical-UV emission, whereas the X-rays remain unabsorbed due to lack of cold neutral gas in the ionised warm absorber. Furthermore, we have investigated the uncertainties in the construction of the spectral energy distribution (SED) of this object due to obscuration of the nuclear source and the effects this has on the photoionisation modelling of the warm absorber. We show how the assumed SEDs influence the thermal stability of each phase and whether or not the two absorber phases in ESO 113-G010can co-exist in pressure equilibrium.

Mehdipour, M.; Branduardi-Raymont, G.; Page, M. J.

2012-06-01

183

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

184

Radar Absorbing Materials: Mechanisms and Materials.  

National Technical Information Service (NTIS)

An introduction is given to the theoretical basis for the design of radar absorbing materials (RAM) with emphasis given on techniques for modifying material properties to give the desired performance. These techniques include additives in the form of scat...

K. Gaylor

1989-01-01

185

FFTF absorber-pin performance verification test  

SciTech Connect

The FFTF (Fast Flux Test Facility) Absorber Pin Performance Verification Test - (HA006) is an irradiation test of neutron absorber pins with integral temperature and pressure monitoring instrumentation. The pins, containing boron carbide, are representative of the FFTF Row 3 Safety, Row 5 Control and Row 7 Fixed Shim Absorber Assemblies. In the 300 full power days (FPD) this test will reside in its 2610 Position in the reactor, it will generate test data that will be used to infer the effects of irradiation on the absorber assemblies it simulates. Design and fabrication of the test vehicle began in 1976 and the forty-foot test assembly was loaded in the FFTF on February 10, 1981. The test provided data in March 1981 during a series of natural circulation tests, and again in November 1981 during the eight-day full power run establishing base-line data.

Basmajian, J.A.; King, D.C.; Jackson, J.L.; Vogel, M.A.

1982-03-01

186

Measurement of Tampon Absorbency; Test Method Evaluation.  

National Technical Information Service (NTIS)

The 'Syngyna' test, developed by the tampon industry to measure tampon absorbency has been evaluated in the FDA Center for Medical Device Analysis. In addition, two other tests were evaluated which were slight modifications of the 'Syngyna' test but which...

D. E. Marlowe R. M. Weigle R. S. Stauffenberg

1981-01-01

187

Thermal Neutron Spect+a Near Absorbers.  

National Technical Information Service (NTIS)

The perturbation in a thermal neutron spectrum near an absorber immersed in a moderator has been studied using activation techniques. The results show two separate effects for pure thermal spectra, a 'transmission hardening' depending on the energy variat...

C. B. Bigham

1964-01-01

188

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

189

Introduction to Radar Absorbent Materials (RAM).  

National Technical Information Service (NTIS)

The purpose of this Introduction is to present, in a straightforward way, the electromagnetic principles of Radar Absorbent Materials (RAM) for the benefit of the non-electromagnetic-specialist who finds himself involved in this field. The fundamental the...

P. G. Lederer

1986-01-01

190

Highly Absorbent Starch-Containing Polymeric Compositions.  

National Technical Information Service (NTIS)

The patent application concerns aqueous fluid-absorbing compositions comprising water-insoluble alkali salts of saponified gelatinized-starch-polyacrylonitrile graft polymers containing gelatinized starch (GS) and saponified polyacrylonitrile (HPAN). The ...

M. G. Weaver E. B. Bagley G. F. Fants W. M. Doane

1974-01-01

191

21 CFR 872.6050 - Saliva absorber.  

Code of Federal Regulations, 2013 CFR

...FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Miscellaneous Devices § 872...absorb moisture from the oral cavity during dental procedures. (b)...

2013-04-01

192

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

NASA Astrophysics Data System (ADS)

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

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

2007-05-01

193

Porous absorber for solar air heaters  

SciTech Connect

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

Finch, J.A.

1980-09-10

194

Water-Absorbent Polymers: A Patent Survey  

Microsoft Academic Search

Water-absorbent polymers or hydrogels, sometimes defined as superabsorbent polymers (SAP) in the literature, are water-insoluble hydrophilic polymers, able to swell and absorb amounts of water, saline solutions, or physiological fluids as high as 10-1000 times their own weight. They consist of polyelectrolytes or other highly hydrophilic polymeric matrices, usually bearing crosslinking sites along the macromolecular chains in order to avoid

Riccardo Pó

1994-01-01

195

Terahertz backscattering behavior of various absorbing materials  

NASA Astrophysics Data System (ADS)

The Submillimeter-Wave Technology Laboratory (STL) at the University of Massachusetts Lowell has investigated the electromagnetic scattering behavior of various broadband absorbers. Several absorbing materials were tested in a compact radar range operating at a center frequency of 160 GHz. The polarimetric radar cross section was measured at elevation angles from 15° to 75°. In addition to the backscattering behavior, the normal incidence transmittance of the materials was evaluated.

Wu, C.; Gatesman, A. J.; Deroeck, L.; Horgan, T.; Giles, R. H.; Nixon, W. E.

2009-05-01

196

Estimating the radiation absorbed by a human  

Microsoft Academic Search

The complexities of the interactions between long- and short-wave radiation fluxes and the human body make it inherently difficult\\u000a to estimate precisely the total radiation absorbed (R) by a human in an outdoor environment. The purpose of this project was to assess and compare three methods to estimate the\\u000a radiation absorbed by a human in an outdoor environment, and to

Natasha A. Kenny; Jon S. Warland; Robert D. Brown; Terry G. Gillespie

2008-01-01

197

Organic Absorbents for Triple Point Absorption Freeze Crystallization Processes.  

National Technical Information Service (NTIS)

Calculations were made to predict the absorption characteristics of various classes of organic molecules. Pertinent absorption refrigeration characteristics were found to be water-absorbent composition, miscibility of the absorbent and absorbed water, and...

J. A. Heist

1982-01-01

198

21 CFR 868.5300 - Carbon dioxide absorbent.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 false Carbon dioxide absorbent. 868.5300 Section...DEVICES Therapeutic Devices § 868.5300 Carbon dioxide absorbent. (a) Identification. A carbon dioxide absorbent is a device...

2013-04-01

199

21 CFR 868.5310 - Carbon dioxide absorber.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 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...

2013-04-01

200

21 CFR 880.5300 - Medical absorbent fiber.  

Code of Federal Regulations, 2013 CFR

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

2013-04-01

201

Modal properties and stability of centrifugal pendulum vibration absorber systems with equally spaced, identical absorbers  

NASA Astrophysics Data System (ADS)

This work develops an analytical model of centrifugal pendulum vibration absorber systems with equally spaced, identical absorbers and uses it to investigate the structure of the modal vibration properties. The planar model admits two translational and one rotational degrees-of-freedom for the rotor and a single arclength degree-of-freedom for each absorber. The gyroscopic effects from rotor rotation are taken into account. Examination of the associated eigenvalue problem reveals well-defined structure of the vibration modes resulting from the cyclic symmetry of the absorbers. The vibration modes are classified into rotational, translational, and absorber modes. Characteristics of each mode type are analytically proved. The effects of the absorber tuning order on the modes are derived. The critical speeds and flutter instability of the system are studied numerically and analytically.

Shi, Chengzhi; Parker, Robert G.

2012-10-01

202

Absorption enhancement of fractal frequency selective surface absorbers by using microwave absorbing material based substrates  

Microsoft Academic Search

In this paper, the effect of microwave absorbing material-based (MAM) substrate on the absorption properties of fractal frequency selective surface (FSS) absorbers was investigated in detail. The fractal shapes were proposed to construct the schematic diagrams of the FSS unit cell. The absorption properties of the absorber samples containing different substrates, including FR-4dielectric substrate and MAM-based substrate, were exhibited via

Zhangqi Liao; Rongzhou Gong; Yan Nie; Tao Wang; Xian Wang

2011-01-01

203

Research on Cold Water of Ground Absorb the Heat of Dry Heat Rocks Underground of Mine  

Microsoft Academic Search

In order to achieve the heat energy development of mine heat rocks mass of Shandong; described Shandong underground heat water utilization and negative effects of it; put forward the new method of develop mine underground dry heat rocks' energy ; established seepage model of water in the heat rock fissures; the method had a small-scale test in the mine and

Zhang Yongliang; Cai Sijing; Wang Jun; Chen Haiyan

2010-01-01

204

Hot Talk, Cold Science  

NASA Astrophysics Data System (ADS)

One of the hottest topics in climate science is understanding and evaluating the impacts of possible global warming caused by anthropogenic emissions of greenhouse gases. In Hot Talk, Cold Science, S. Fred Singer does not accept global warming. Singer says in his preface, “The purpose of this book is to demonstrate that the evidence [for global warming] is neither settled, nor compelling, nor even convincing. On the contrary, scientists continue to discover new mechanisms for climate change and to put forth new theories to try to account for the fact that global temperature is not rising, even though greenhouse theory says it should”.

Oglesby, Robert J.

205

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

206

Absorbing Information about a Child's Incurable Cancer  

PubMed Central

Purpose To assess parents’ ability to absorb information that their child's cancer was incurable and to identify factors associated with parents’ ability to absorb this information. Patients and Methods: An anonymous mail-in questionnaire study was performed as a population-based investigation in Sweden between August and October of 2001. 449 parents who lost a child to cancer 4–9 years earlier (response rate 80%) completed the survey. 191 (43%) of the bereaved parents were fathers and 251 (56%) were mothers. Results Sixty percent of parents (n = 258) reported that they were able to absorb the information that their child's illness was incurable. Parents were better able to absorb this information when the information was given in an appropriate manner (RR 1.6; CI 1.3–2.0), when they shared their problems with others during the child's illness course (RR 1.4; CI 1.1–1.8) and when they had no history of depression (RR 1.3; CI 1.0–1.8). Parents who reported that they were able to absorb the information were more likely to have expressed their farewells to the child in their desired manner (RR 1.3; CI 1.0–1.5). Conclusions Parents who received information that their child's illness was incurable in an appropriate manner are more likely to absorb that information. Whether or not parents are able to absorb the information that their child's cancer is incurable has implications in terms of preparation for the child's impending death.

Lannen, Patrizia; Wolfe, Joanne; Mack, Jennifer; Onelov, Erik; Nyberg, Ullakarin; Kreicbergs, Ulrika

2010-01-01

207

Gas absorber and refrigeration system using same  

SciTech Connect

A refrigeration system is described comprising: (a) a separator for separating a refrigerant gas from a refrigerant-rich solution to produce a refrigerant-lean solution; (b) a condenser for emitting heat to thereby condense the refrigerant gas received from the separator and an evaporator for absorbing heat to thereby evaporate the condensed refrigerant gas; (c) an absorber assembly including: a precooler for precooling the refrigerant-lean solution received from the separator; a mixer for mixing the refrigerant gas from the evaporator with the precooled refrigerant-lean solution received form the precooler to thereby form a gas-solution mixture, the mixer having nozzles for allowing the refrigerant-lean solution to be injected there through into a flow of the gas-solution mixture, the nozzles being adapted to cause the refrigerant-lean solution to experience a predetermined pressure drop there across; and absorbent tubes for allowing the gas-solution mixture to flow there through while causing the refrigerant-lean solution to absorb the refrigerant gas to thereby generate a refrigerant-rich solution; (d) a solution receiver for receiving the refrigerant-rich solution through the absorber tubes and a manifold for containing an overflow through the absorber tubes during a normal operation of the refrigeration system, an upper part of the solution receiver serving to contain the refrigerant gas; (e) recycling means for controllably recycling the refrigerant gas from the solution receiver into the absorber assembly; and a solution pump for delivering the refrigerant-rich solution from the solution receiver to the separator through a generator for heating the refrigerant-rich solution.

Dehne, H.

1993-08-24

208

ANL Advanced Photon Source crotch absorber design  

SciTech Connect

The ANL 7-GeV Advanced Photon Source storage ring crotch absorber will be subjected to a very high photon loading power density, approximately 750 W/mm{sup 2} at normal incidence. To accommodate this high heat load, two designs were studied: one is a V-type compound angle absorber and the other is a horizontally rotated plate absorber. For both models, thermal and structural analyses have been carried out using 3-D finite element analysis. The analysis indicates that the V-type compound angle absorber controlled the peak temperatures effectively within the given geometric constraints. Test samples made of GlidCop Al 15 (alumina dispersion strengthened copper) were evaluated with an electron beam welder. The predicted and measured temperatures were in reasonable agreement. The overall absorber design includes a perforated screen in the positron beam area of the storage ring vacuum chamber to reduce rf impedance and to provide pumping access for the high local gas load. 3 refs., 4 figs., 2 tabs.

Choi, M. (Seoul National Univ. (Republic of Korea)); Gonczy, J.D.; Howell, J.W.; Niemann, R.C. (Argonne National Lab., IL (USA))

1991-01-01

209

Non-Absorbable Gas Behavior in the Absorber/Evaporator of a Absorption Chiller  

NASA Astrophysics Data System (ADS)

A two-dimensional numerical study on non-absorbable gas behavior in the absorber/evaporator of an absorption chiller has been performed. In the present study, the effect of the pitch-to-diameter ratio of a cylinder bundle in the absorber was highlighted. From the results, a sudden decrease of the overall heat transfer coefficient of the absorber was observed at a certain mean concentration of non-absorbable gas for each pitch-to-diameter ratio. Such a critical concentration was also found to decrease as the pitch-to- diameter ratio increased. The sudden decrease occurs due to the sudden disappearance of recirculating region, which is formed between the absorber and the evaporator, and where most of non-absorbable gas stays when it exists. As the pitch-to-diameter ratio increases, the recirculating region becomes weak because the velocity of the high velocity region supporting the recirculating flow decreases. Then, the critical mean concentration of non-absorbable gas is found to decrease as pitch-to-ratio increases.

Suzuki, Hiroshi; Nagamoto, Wataru; Sugiyama, Takahide

210

Design, simulation, and measurement of metamaterial absorber  

NASA Astrophysics Data System (ADS)

We present a design for metamaterial absorber which is resonant with strong absorbance in the microwave frequency range. Our fabricated design consists of two resonators and a metal wire that couple separately so as to absorb all incident electric and magnetic fields within a single planar layer which is only 0.9 mm thick. Experiments demonstrate that the transmission coefficients (S21) are lower than -10 dB across the entire measurement frequency range and the reflectance coefficients (S11) are about -20 dB around 10.4 GHz. The absorptivity which can be obtained through S parameters is greater than 98% around 10.4 GHz in experiments and 99.9% in simulations.

Cheng, Yongzhi; Yang, Helin

2010-08-01

211

Distributed electric absorbers of beam vibrations  

NASA Astrophysics Data System (ADS)

Several electric vibration absorbers based on distributed piezoelectric control of beam vibrations are studied. The damping devices are conceived by interconnecting with different modular electric networks an array of piezoelectric transducers uniformly distributed on a beam. Five different vibration absorbers made of five different network interconnecting topologies are considered and their damping performances are analyzed and compared. The analysis is based on homogenized models of modular piezo-electromechanical systems. The optimal parameters of these absorbers are found by adopting the criterion of critical damping of waves with a single wave number. We show that: i) there is an interconnecting network providing an optimal multimodal damping; ii) the performances required to the electr(on)ic components can be significantly decreased by increasing the number (and decreasing the dimensions) of the piezoelectric transducers.

dell'lsola, Francesco; Del Vescovo, Dionisio; Maurini, Corrado

2003-07-01

212

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

213

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

214

Human Vascular Fluid Responses to Cold Stress Are Not Altered by Cold Acclimation.  

National Technical Information Service (NTIS)

Repeated cold water immersion can induce the development of an insulative type of cold acclimation in man. This investigation determined if repeated cold water immersion produced changes in vascular fluid response to cold stress in addition to the previou...

A. J. Young S. R. Muza M. N. Sawka K. B. Pandolf

1986-01-01

215

Wavelength-tunable microbolometers with metamaterial absorbers.  

PubMed

Microbolometers are modified by metallic resonant absorber elements, leading to an enhanced responsivity at selectable wavelengths. The dissipative energy absorption of tailored metamaterials allows for engineering the response of conventional bolometer microbridges. The absorption peak position and height are determined by the geometry of the metamaterial. Square-shaped metal/dielectric/metal stacks as absorber elements show spectral resonances at wavelengths between 4.8 and 7.0 microm in accordance with numerical simulations. Total peak absorptions of 0.8 are obtained. The metamaterial modified bolometers are suitable for multispectral thermal imaging systems in the mid-IR and terahertz regime. PMID:19794799

Maier, Thomas; Brückl, Hubert

2009-10-01

216

Optical axes in various absorbing crystals  

NASA Astrophysics Data System (ADS)

Analytical expressions have been derived for the components of the complex permittivity tensor as a function of the number of optical axes existing in an absorbing monoclinic crystal. Some specific features of the orientation of these axes are considered. The ellipticities of natural waves are calculated for these crystals, as well as the ellipticities of transmitted light for right- or left-hand circularly polarized waves normally incident on a crystal. A significant difference of particular cases of absorbing monoclinic crystals from the general case of crystal with four circular axes is demonstrated.

Golovina, T. G.; Konstantinova, A. F.; Evdishchenko, E. A.; Nabatov, B. V.; Konstantinov, K. K.

2012-11-01

217

Absorbing phase transition in energy exchange models  

NASA Astrophysics Data System (ADS)

We study energy exchange models with dissipation (?) and noise (of amplitude ?) and show that in presence of a threshold these models undergo an absorbing phase transition when either dissipation or noise strength or both are varied. Using Monte Carlo simulations we find that the behaviour along the critical line, which separates the active phase from the absorbing one, belongs to directed percolation (DP) universality class. We claim that the conserved version with ? = 1 and ? = 0 also shows a DP transition; the apparent non-DP behaviour observed earlier is an artifact of undershooting in the decay of activity density starting from a random initial condition.

Basu, U.; Basu, M.; Mohanty, P. K.

2013-05-01

218

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

219

Cold quark matter  

NASA Astrophysics Data System (ADS)

We perform an O(?s2) perturbative calculation of the equation of state of cold but dense QCD matter with two massless and one massive quark flavor, finding that perturbation theory converges reasonably well for quark chemical potentials above 1 GeV. Using a running coupling constant and strange quark mass, and allowing for further nonperturbative effects, our results point to a narrow range where absolutely stable strange quark matter may exist. Absent stable strange quark matter, our findings suggest that quark matter in (slowly rotating) compact star cores becomes confined to hadrons only slightly above the density of atomic nuclei. Finally, we show that equations of state including quark matter lead to hybrid star masses up to M˜2M?, in agreement with current observations. For strange stars, we find maximal masses of M˜2.75M? and conclude that confirmed observations of compact stars with M>2M? would strongly favor the existence of stable strange quark matter.

Kurkela, Aleksi; Romatschke, Paul; Vuorinen, Aleksi

2010-05-01

220

Cold / Smallest Ice  

NSDL National Science Digital Library

This radio broadcast contains a discussion with the author of a book about history, heat, and the quest for absolute zero. Absolute zero, (-273.15 degrees Celsius), the temperature at which all molecules stop moving entirely, is ultimately cold. Research into what temperature really means and ways to alter the temperature of objects has resulted in more efficient engines, air conditioning, new materials, and even a new form of matter, the Bose-Einstein Condensate. The broadcast also contains discussion about researchers who say that they have made the smallest piece of ice possible - a hexagonal shape built out of just six molecules of water. (A normal drop of water contains about 100,000,000,000,000,000,000 water molecules). The research may help the scientists examine how water molecules bond together, information of great interest to biologists, chemists, and pharmaceutical researchers. The broadcast is 47 minutes in length.

221

Nonfreezing Cold-Induced Injuries.  

National Technical Information Service (NTIS)

Nonfreezing cold-induced injury (NFCI) is a clinical syndrome that results from damage caused to tissues exposed to cold temperatures at or above the freezing point of water (0 deg to 15 deg C 32 deg to 59 deg F). NFCI does not involve tissue freezing, wh...

C. H. Imray J. W. Castellani

2012-01-01

222

Caffeine and the common cold  

Microsoft Academic Search

An experiment was carried out to determine whether caffeinated and decaffeinated coffee removed the malaise (reduced alertness, slower psychomotor performance) associated with having a common cold. One hundred volunteers were tested when healthy and 46 returned to the laboratory when they developed colds. Those subjects who remained healthy were then recalled as a control group. On the second visit subjects

Andrew Smith; Marie Thomas; Kate Perry; Helen Whitney

1997-01-01

223

Nanofriction in cold ion traps  

Microsoft Academic Search

Sliding friction between crystal lattices and the physics of cold ion traps are so far non-overlapping fields. Two sliding lattices may either stick and show static friction or slip with dynamic friction; cold ions are known to form static chains, helices or clusters, depending on the trapping conditions. Here we show, based on simulations, that much could be learnt about

A. Benassi; A. Vanossi; E. Tosatti

2011-01-01

224

Hypothermia and localized cold injuries  

Microsoft Academic Search

Accidental hypothermia and localized cold injuries remain a significant public health problem. The deleterious effect of cold exposure on human performance and health has been documented for centuries. Some of the earliest descriptions came from Baron de Larrey, Napoleon's chief surgeon. During the disastrous invasion of Russia in 1812 he depicted the mental and physical hardships endured by the French

Andrew S. Ulrich; Niels K. Rathlev

2004-01-01

225

Microscopic Mechanism for Cold Denaturation  

Microsoft Academic Search

We elucidate the mechanism of cold denaturation through constant-pressure simulations for a model of hydrophobic molecules in an explicit solvent. We find that the temperature dependence of the hydrophobic effect induces, facilitates, and is the driving force for cold denaturation. The physical mechanism underlying this phenomenon is identified as the destabilization of hydrophobic contact in favor of solvent-separated configurations, the

Cristiano L. Dias; Tapio Ala-Nissila; Mikko Karttunen; Ilpo Vattulainen; Martin Grant

2008-01-01

226

Encyclopedia of the Cold War  

Microsoft Academic Search

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

Dijk van R

2008-01-01

227

Going deep for cold water  

Microsoft Academic Search

The cold sink comtemplated for ocean thermal energy conversion (OTEC) plants resides several thousand feet below the surface of the ocean. Therefore, the success of the OTEC concept depends in part on the development of a means to tap this sink. Although bringing up cold waters from the depths of the ocean to an OTEC plant has never been regarded

H. Ottsen; J. R. Maison

1977-01-01

228

Cold War history in Italy  

Microsoft Academic Search

The article aims at reviewing the historical production on the Cold War in Italy (both research and teaching activities). Some preliminary remarks deal with the Italian university system and the role some historical disciplines, especially the history of international relations, play in such a context. In Italy, historical studies on the Cold War had their origins in the 1970s mainly

Antonio Varsori

2008-01-01

229

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

230

Genetic algorithm design of Pareto optimal broadband microwave absorbers  

Microsoft Academic Search

The concept of Pareto optimality is applied to the study of choice tradeoffs between reflectivity and thickness in the design of multilayer microwave absorbers. Absorbers composed of a given number of layers of absorbing materials selected from a predefined database of available materials are considered. Three types of Pareto genetic algorithms for absorber synthesis are introduced and compared to each

D. S. Weile; E. Michielssen; D. E. Goldberg

1996-01-01

231

Tips to Protect Workers in Cold Environments  

MedlinePLUS

... during normal business hours.) Tips To Protect Workers In Cold Environments Prolonged exposure to freezing or cold ... problems such as trench foot, frostbite and hypothermia. In extreme cases, including cold water immersion, exposure can ...

232

Wave propagation in a disordered absorbing waveguide  

NASA Astrophysics Data System (ADS)

We consider scattering of wave from a disordered absorbing waveguide. Starting from the invariant-imbedding equations, we derive a Fokker-Plank equation for the joint probability distribution of the reflection eigenvalues. When absorption is absent, this equation reduces to the well-known Dorokhov-Mello-Pereyra-Kumar equation. The limits of the validity of the equation are carefully examined.

Pustilnik, Michael

1997-03-01

233

Impact Response of an Energy Absorbing Earcup.  

National Technical Information Service (NTIS)

Twelve impacts tests on instrumented human cadavers were performed at Wayne State University to compare the load attenuating capability of an energy absorbing earcup with that of the standard rigid earcup used in SPH-4 flight helmets. SPH-4 helmeted cadav...

D. F. Shanahan

1983-01-01

234

Design of a wideband radar absorbing structure  

Microsoft Academic Search

In this paper, a thin planar electromagnetic absorber consisting of two lossy Frequency Selective Surface (FSS) layers is introduced. The layers are separated by foam material and they are backed by the ground plane. Square rings and crossed dipoles are used in the design of these lossy layers. A wideband absorption characteristic is achieved for zero degrees of incidence angle

Egemen Yildirim; Ozlem Aydin Civi

2011-01-01

235

Solar Absorber Surfaces Treated by Femtosecond Laser  

Microsoft Academic Search

Using a femtosecond laser surface structuring technique, we produce technologically important solar absorbers (black aluminum, titanium, tungsten, copper, and stainless steel) with absorptance of about 85-95% over a broad wavelength range from ultraviolet to infrared. Scanning electron microscopy shows that the enhanced absorption of the black metals is caused by a rich variety of nano- and microscale surface structures. The

Anatoliy Y. Vorobyev; Chunlei Guo

2010-01-01

236

Inverse scattering problems in absorbing media  

Microsoft Academic Search

We study inverse scattering problems which occur in various fields of physics (transmission lines theory, electromagnetism, elasticity theory), and in which the inhomogeneous media considered are absorbing. We suppose that waves propagate in a z direction from z=0 to z=? and are totally reflected at z=0, the input data being the values of the reflection coefficient to the right S+(k)

M. Jaulent

1976-01-01

237

ANL Advanced Photon Source crotch absorber design.  

National Technical Information Service (NTIS)

The ANL 7-GeV Advanced Photon Source storage ring crotch absorber will be subjected to a very high photon loading power density, approximately 750 W/mm(sup 2) at normal incidence. To accommodate this high heat load, two designs were studied: one is a V-ty...

M. Choi J. D. Gonczy J. W. Howell R. C. Niemann

1991-01-01

238

Ultrasonic waves propagation in absorbing thin plates  

Microsoft Academic Search

Guided wave theory is applied to a thin orthotropic and absorbing plate for low frequency propagation of ultrasonic waves. The aim of this paper is to give some physical interpretations of the non-destructive characterization of paper materials, which are cellulosic fibrous networks. It is shown that the propagation problem reduces to two normal modes of propagation in the plane of

A. Bonnin; R. Huchon; M. Deschamps

2000-01-01

239

Absorption cross section of absorber cylinders  

NASA Astrophysics Data System (ADS)

The paper covers derivation and calculation of absorption and scattering cross sections of three types of cylinders made out of porous absorber material. These types are, respectively, (a) completely bulk reacting (homogeneous and isotropic), (b) axially locally reacting but bulk reacting about the circumference (rigid partitions inserted normal to the cylinder's axis), and (c) locally reacting in all directions. The sound field may be either plane waves with oblique incidence or diffuse sound fields. The characteristic data used for the absorber materials, propagation constant and wave impedance, are in the form of simple approximations taken from a model theory of fibrous absorbers for low frequencies, with experimental data being used at medium and high frequencies. A formulation of the scattered sound field in series of Bessel function is used. The numerical results show the influence of the frequency, the diameter, the materials' flow resistance and the angle of incidence. Maps are plotted of lines of constant absorption cross-sections for the different types of cylinders and sound fields, revealing the dependence upon these parameters. Acoustical phenomena of the sound absorption by absorber cylinders are discussed, such as resonance scattering, surface waves, frequency ranges with small angular dependence and parameter combinations with only small frequency dependence of the absorption. Such cylinders would be appropriate as calibration objects in round robin tests of sound absorption measurement in reverberant rooms.

Mechel, F. P.

1986-05-01

240

Absorption enhancement of fractal frequency selective surface absorbers by using microwave absorbing material based substrates  

NASA Astrophysics Data System (ADS)

In this paper, the effect of microwave absorbing material-based (MAM) substrate on the absorption properties of fractal frequency selective surface (FSS) absorbers was investigated in detail. The fractal shapes were proposed to construct the schematic diagrams of the FSS unit cell. The absorption properties of the absorber samples containing different substrates, including FR-4dielectric substrate and MAM-based substrate, were exhibited via the Naval Research Laboratory (NRL)-arch method, respectively. Then the power loss density distributions of the absorbers were illustrated by the finite integration technology (FIT) method to obtain an insight of the physical picture into the absorption properties. The results indicate that with the increase of the substrate thicknesses, the FR-4-based FSS absorbers could achieve the strongest absorbing performance at a certain thickness. However, employing the MAM-based substrate to replace the FR-4 substrate with the same substrate thickness enhances the absorbing properties greatly, including the peak values and the bandwidths. As a result, the way of introducing the MAM-based substrates instead of the traditional dielectric substrates provides a potential practical application in device miniaturization.

Liao, Zhangqi; Gong, Rongzhou; Nie, Yan; Wang, Tao; Wang, Xian

2011-07-01

241

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

NASA Astrophysics Data System (ADS)

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 GHz was created. Based on the database, the single-layer and double-layer absorbers were designed and prepared, and their microwave absorption properties were investigated. The results indicate that the carbonyl iron powder prepared via thermal decomposition of iron pentacarbonyl is single cubic iron and of spherical shape. The barium ferrite powder is single W-type ferrite and a hexagonal flake. The absorption band of the double-layer microwave absorber is obviously more than that of the single-layer absorber. The double-layer microwave absorbers with reflection loss <-13 dB over the range of 6 18 GHz and reflection loss <-8 dB over the range of 2 18 GHz were prepared. The thicknesses of the absorbers are only 3.6 and 3.7 mm, respectively.

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

2007-11-01

242

Radiative and climate impacts of absorbing aerosols  

NASA Astrophysics Data System (ADS)

By integrating experimental data, radiative transfer theory, and numerical modelling, this dissertation aims to improve our understanding of the radiative and the climate impacts of the major absorbing aerosols: mineral dust, black carbon (BC) and brown carbon. The research presented here combines existing surface, satellite and aircraft measurements and develops self-consistent models for aerosol mixing state, global and regional radiative forcing of absorbing aerosols and their climate effects. The first part of this dissertation presents the climatology and radiative impacts of dust plumes over the Pacific, the Indian and the Atlantic Oceans using multiple satellite datasets in conjunction with MACR (Monte Carlo Aerosol-Cloud-Radiation) model. A core-shell internally mixed aerosol model has been developed using the microphysical, chemical, and radiative observations as constraints. It is shown that internal mixing enhances the aerosol absorption and contributes to over 20% increase of radiative forcing. The aerosol mixing model is validated by comparing model simulated spectrally-resolved irradiance with observations. The results show that aerosol induced forcing is mainly confined in the visible band and the largest forcing occurs in the blue channel. Having validated the modelling of the mixing-state of absorbing aerosols with broadband and high-resolution spectral radiation data, global three-dimensional distribution of the spectral radiative forcing is obtained. The aerosol forcing is used to drive a general circulation model (GCM) with prescribed sea surface temperature to investigate the impact of absorbing aerosols on regional climate. One of the main model findings is that heating of the atmosphere by absorbing aerosols can contribute to significant reductions in low level clouds, which in turn amplifies the warming. The simulated cloudiness reduction is particularly strong over the Arctic and China and the simulated warming over the Arctic exceeds 1.5°C. The findings of cloud reduction over China and the warming over the Arctic are consistent with observations. The above effects are relatively weak or negligible when absorbing aerosols are treated as externally mixed which is used as the assumption by most GCM studies thus far. This study reveals the fundamental importance of accounting for the observed chemical and physical properties of absorbing aerosols.

Zhu, Aihua

243

Absorbed fractions for electrons in ellipsoidal volumes  

NASA Astrophysics Data System (ADS)

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

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

2011-01-01

244

Cold Fusion, A Journalistic Investigation  

NASA Astrophysics Data System (ADS)

Author of the recent book, The Rebirth of Cold Fusion, and founder of New Energy Times, Steven B. Krivit presents a summary of cold fusion's, past, present and possible future. This talk will briefly review five highlights of the recent New Energy Times investigation into cold fusion research:1. Analysis of early studies that supposedly disproved cold fusion.2. Key early corroborations that supported the claims of Fleischmann and Pons.3. The evolving understanding of cold fusion reaction paths and by-products.4. A look at volumetric power density.5. Brief comparison of the progress in hot fusion research as compared to cold fusion research.New Energy Times, founded in 2000, is an independent communications company which currently specializes in reporting on cold fusion researchootnotetextReferences and copies of the presentation are available at www.newenergytimes.com/reports/aps2005.htmhttp://www.newenergytimes.com/reports/aps2005.htm. It has no affiliations with any organization, entity or party which invests in these technologies, nor any individual researcher or research facility.

Krivit, Steven B.

2005-03-01

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

2011-12-09

246

Inside The Cold War. A Cold Warrior's Reflections.  

National Technical Information Service (NTIS)

This publication reflects a compilation of excerpts from an unpublished broader treatment that recounts the nearly five decades of delicate coexistence between two nations known as the 'superpowers' during the international conflict known as the 'Cold War...

C. Adams

1999-01-01

247

Method of warming cold engines in cold climates  

SciTech Connect

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

Forschirm, A.

1988-12-06

248

Versatile cold atom target apparatus  

NASA Astrophysics Data System (ADS)

We report on a compact and transportable apparatus that consists of a cold atomic target at the center of a high resolution recoil ion momentum spectrometer. Cold rubidium atoms serve as a target which can be operated in three different modes: in continuous mode, consisting of a cold atom beam generated by a two-dimensional magneto-optical trap, in normal mode in which the atoms from the beam are trapped in a three-dimensional magneto-optical trap (3D MOT), and in high density mode in which the 3D MOT is operated in dark spontaneous optical trap configuration. The targets are characterized using photoionization.

Götz, Simone; Höltkemeier, Bastian; Hofmann, Christoph S.; Litsch, Dominic; DePaola, Brett D.; Weidemüller, Matthias

2012-07-01

249

Microscopic Mechanism for Cold Denaturation  

NASA Astrophysics Data System (ADS)

We elucidate the mechanism of cold denaturation through constant-pressure simulations for a model of hydrophobic molecules in an explicit solvent. We find that the temperature dependence of the hydrophobic effect induces, facilitates, and is the driving force for cold denaturation. The physical mechanism underlying this phenomenon is identified as the destabilization of hydrophobic contact in favor of solvent-separated configurations, the same mechanism seen in pressure-induced denaturation. A phenomenological explanation proposed for the mechanism is suggested as being responsible for cold denaturation in real proteins.

Dias, Cristiano L.; Ala-Nissila, Tapio; Karttunen, Mikko; Vattulainen, Ilpo; Grant, Martin

2008-03-01

250

Versatile cold atom target apparatus  

SciTech Connect

We report on a compact and transportable apparatus that consists of a cold atomic target at the center of a high resolution recoil ion momentum spectrometer. Cold rubidium atoms serve as a target which can be operated in three different modes: in continuous mode, consisting of a cold atom beam generated by a two-dimensional magneto-optical trap, in normal mode in which the atoms from the beam are trapped in a three-dimensional magneto-optical trap (3D MOT), and in high density mode in which the 3D MOT is operated in dark spontaneous optical trap configuration. The targets are characterized using photoionization.

Goetz, Simone; Hoeltkemeier, Bastian; Hofmann, Christoph S.; Litsch, Dominic; DePaola, Brett D.; Weidemueller, Matthias [Physikalisches Insitut, Universitaet Heidelberg, Philosophenweg 12, 69120 Heidelberg (Germany)

2012-07-15

251

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

252

Process for producing cold and/or heat by means of an adsorption cycle comprising at least two absorption steps  

SciTech Connect

A process is provided for producing cold and/or heat by means of a thermal unit operating by absorption. Increased performances are obtained by using a condensable auxiliary fluid and performing the absorption in two successive steps. The unit for conducting the process essentially comprises a generator, a condenser, an evaporator and two absorbers.

Rojey, A.; Bonifay, R.; Cariou, J.-P.

1985-08-06

253

Acclimatization to Cold in Humans.  

National Technical Information Service (NTIS)

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 s...

H. Kaciuba-Uscilko J. E. Greenleaf

1989-01-01

254

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

255

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

256

Absorbing Software Testing into the Scrum Method  

NASA Astrophysics Data System (ADS)

In this paper we study, how to absorb software testing into the Scrum method. We conducted the research as an action research during the years 2007-2008 with three iterations. The result showed that testing can and even should be absorbed to the Scrum method. The testing team was merged into the Scrum teams. The teams can now deliver better working software in a shorter time, because testing keeps track of the progress of the development. Also the team spirit is higher, because the Scrum team members are committed to the same goal. The biggest change from test manager’s point of view was the organized Product Owner Team. Test manager don’t have testing team anymore, and in the future all the testing tasks have to be assigned through the Product Backlog.

Tuomikoski, Janne; Tervonen, Ilkka

257

Liquid neutron absorber alternatives for the MPTRR  

SciTech Connect

The Multi-Purpose Type Research Reactor (MPTRR) control and first shutdown systems consist of six control plates of a Ag-In-Cd alloy. The second shutdown system is given by a liquid neutron absorber, a solution of boric acid, filling the inside of the chimney separating the core from the reflectors. The chimney is composed of four sides (four independent systems), each of them formed by two Zircaloy walls of 0.6 cm, and the empty central space inside (1.8 cm) filled with pure nitrogen during normal operation. The licensing criterion for the second shutdown system (the chimney, for brevity) requires a reactivity worth of {approximately}5000 pcm. The purpose of the work is the analysis of alternative liquid absorbers and the maximum reactivity worth reachable by the second shut-down system.

Jatuff, F.E.; Villarino, E.A. [INVAP S.E., S.C. de Bariloche (Argentina)

1995-12-31

258

Driving apparatus for an absorber rod  

SciTech Connect

A driving apparatus for raising and lowering an absorber rod within a nuclear reactor pressure vessel is described. The apparatus comprises a driving system which includes a motor-driven flexible support member that is connected to the absorber rod through both a coupling element and a connecting element, and a storage means for storing any excess length of flexible support member. Both the driving system and the storage means are detachably enclosed within a desired gaseous environment that is isolated from the interior of the pressure vessel by a screening plug having a passageway therein through which the connecting element is disposed for movement between an upper end position and a lower end position.

Cramer, H.; Handel, H.; Maisach, M.S.; Schmitt, H.; Schoening, J.

1980-08-26

259

Water-absorbing balls: a "growing" problem.  

PubMed

Foreign body ingestion is a potentially serious clinical problem in children. We report a case of an 8-month-old infant who developed complete bowel obstruction requiring laparotomy due to ingestion of a superabsorbent polymer ball with advertised growth up to 400 times its original size. Most ingested foreign bodies that pass through the pylorus will make it safely through the gastrointestinal tract. This is not true for water-absorbing balls that progressively increase in size and cause intestinal obstruction. Other household products and toys on the market use a similar polymer-based water-absorbing technology, thus increasing the risk for accidental ingestion by young children. These rapidly expanding objects can cause significant morbidity, and timely diagnosis and treatment are prudent to improve patient outcomes. PMID:22987870

Zamora, Irving J; Vu, Lan T; Larimer, Emily L; Olutoye, Oluyinka O

2012-09-17

260

Wide band cryogenic ultra-high vacuum microwave absorber  

DOEpatents

An absorber wave guide assembly for absorbing higher order modes of microwave energy under cryogenic ultra-high vacuum conditions, that absorbs wide-band multi-mode energy. The absorber is of a special triangular shape, made from flat tiles of silicon carbide and aluminum nitride. The leading sharp end of the absorber is located in a corner of the wave guide and tapers to a larger cross-sectional area whose center is located approximately in the center of the wave guide. The absorber is relatively short, being of less height than the maximum width of the wave guide.

Campisi, Isidoro E. (Newport News, VA)

1992-01-01

261

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

262

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

263

Cold gas in elliptical galaxies  

Microsoft Academic Search

We explore the evolution of the cold gas (molecular and neutral hydrogen) of\\u000aelliptical galaxies and merger remnants ordered into a time sequence on the\\u000abasis of spectroscopic age estimates. We find that the fraction of cold gas in\\u000aearly merger remnants decreases significantly for ~1-2 Gyr, but subsequent\\u000aevolution toward evolved elliptical systems sees very little change. This trend

A. Georgakakis; P A. M. Hopkins; P A. Caulton; T. Wiklind; A. I. Terlevich; Duncan A. Forbes

2001-01-01

264

Trends in radar absorbing materials technology  

Microsoft Academic Search

The research in the area of Radar Absorbing Materials (RAMs) has been actively pursued for at least four decades. Although\\u000a resonant RAMs were originally designed by transmission line approach, and the broad band RAMs were obtained by multilayering,\\u000a the quest for ultrawide band performance has led to novel approaches such as chirality and even exploring biochemical products.\\u000a It is observed

K J Vinoy; R M Jha

1995-01-01

265

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); Bryan A. Laffitte (University of California, Los Angeles (UCLA) School of Medicine;Howard Hughes Medical Institute); Aldons J. Lusis (University of California, Los Angeles (UCLA) School of Medicine;Department of Medicine and the Department of Microbiology, Immunology and Molecular Genetics)

2000-12-01

266

Long pathlength, three-dimensional absorbance microchip  

Microsoft Academic Search

A long pathlength, three-dimensional U-type flow cell was microfabricated and evaluated for improved absorbance detection on a glass microdevice. A small diameter hole (75?m) was laser etched in a thin glass substrate whose thickness (100?m) defined much of the pathlength of the cell. This substrate was thermally bonded and sandwiched between two different glass substrates. The top substrate contained a

Greg E. Collins; Qin Lu; Nicholas Pereira; Peter Wu

2007-01-01

267

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

268

Cosmic Dust in Mg II Absorbers  

NASA Astrophysics Data System (ADS)

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 ? ? 2 × 10-6, 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 ? ? 1.5 × 10-4, 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 Å, at which the absorption by the Lyman edge dominates over scattering by dust in the extinction opacity.

Ménard, Brice; Fukugita, Masataka

2012-08-01

269

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

270

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.

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

2002-01-01

271

Cold regions hydrology, snow, and PUB  

Microsoft Academic Search

Cold regions hydrology has a great demand for improved prediction because most cold regions are notoriously ungauged and because the cold regions hydrological cycle has some uniquely important components related to the solid phase of water. For instance, snow accumulation controls water balance and peak streamflow in many cold region catchments. However, the quantity of snow accumulated in forested catchments

JOHN POMEROY

2007-01-01

272

Effect of cold acclimatization on exercise economy in the cold.  

PubMed

We sought to determine if cold acclimatized men display higher economy (i.e. lower oxygen consumption at a given workload) during graded cycle ergometry in the cold (5°C). After completing a familiarization trial 1 week prior, five cold weather athletes (CWA) and eight physically active men (NON) underwent graded exercise tests to volitional fatigue in 5°C. The protocol always started at 60 W and increased by 20 W each minute. Oxygen consumption (VO(2)), respiration rate (RR), tidal volume (TV), and respiratory exchange ratio (RER) were determined via open circuit spirometry. Individuals were matched for body size and minutes of weekly physical activity. Repeated measures analyses of variance were conducted across time (workload) and cold acclimatization was entered as a between subjects factor. VO(2) peak was not different between groups but CWA had lower VO(2) at 60 and 240 W. CWA also had lower RR at 180 and 260 W as well as lower RER at 240 and 260 W. At submaximal workloads, cold acclimatized men have higher exercise economy than non-acclimatized men. This could have implications for those who work in this context. PMID:21671101

Muller, Matthew D; Kim, Chul-Ho; Bellar, David M; Ryan, Edward J; Seo, Yongsuk; Muller, Sarah M; Glickman, Ellen L

2011-06-14

273

Cold Fusion at Hotspots  

NASA Astrophysics Data System (ADS)

Olivine-liquid FeO-MgO (OLFM) equilibria is often assumed and used to estimate eruptive (To) and melting (potential) temperatures (TP) of primitive magmas and their MgO contents at spreading ridges and linear volcanic chains. The technique involves incremental addition of melt calculated to be in equilibrium with successively more magnesian olivine until an olivine of “mantle” composition is reached. Incremental olivine addition depends on the assumption that that this olivine and the host liquid lie along a single liquid line of descent determined by crystallization of olivine and no other mineral; i.e., the parental liquid was formally picritic in composition. This assumption can be questioned on three grounds, which may vary in importance from place to place, but at least one of which always appears to be operative: 1) most picrites are hybrids between primitive and differentiated magmas, the latter expressing cotectic crystallization of olivine, plagioclase and/or clinopyroxene (e.g., Baffin-West Greenland, Hawaii, Samoa), and have higher Fe/Mg than primitive magma, making estimates of To and TP too high; 2) the rocks themselves contain phenocrysts of plagioclase (e.g., Iceland) and/or clinopyroxene (e.g., Samoa) as well as olivine; 3) not even the most primitive magmas, evidenced by mineral associations in accumulative magmatic xenoliths (dunite, wehrlite, olivine clinopyroxene; many examples) indicate stages of crystallization involving olivine by itself. An alternative approach that uses liquid compositions to estimate compositions of Cr-spinel (Poustovetov and Roeder, 2000) predicts no natural Cr-spinel that crystallized at temperature >1400C or pressure 1.5 GPa either in picrites or xenoliths at any of these localities; no parental liquid had MgO > 16%. Spinel predicted from high-MgO (>20%) parental liquids postulated by OLFM matches nothing in nature. Natural glass in Samoan harzburgite xenoliths is mainly differentiated basalt, hawaiite and mugearite with average melt temperature of ~1100C, the same temperature as given by Ca-in-orthopyroxene of the harzburgites. Cold ambient mantle draws heat from ascending magma, forcing differentiation at depth. Magma with TP greater by 200C than primitive basalt at spreading ridges does not exist at any of these places. TP does not constrain temperature of the mantle below the depth of melt extraction. High and variable 3He/4He at all these places may result from volatile incorporation from old harzburgite through which magmas must ascend. Poustovetov, A., and Roeder, P.L., 2000. Canad. Min. 39: 309-317.

Natland, J. H.

2009-12-01

274

21 CFR 880.6025 - Absorbent tipped applicator.  

Code of Federal Regulations, 2013 CFR

...absorbent tipped applicator is a device intended for medical purposes that consists of an absorbent swab on a wooden, paper, or plastic stick. The device is used to apply medications to, or to take specimens from, a patient. (b)...

2013-04-01

275

Material Model Evaluation of a Composite Honeycomb Energy Absorber.  

National Technical Information Service (NTIS)

A study was conducted to evaluate four different material models in predicting the dynamic crushing response of solid-element-based models of a composite honeycomb energy absorber, designated the Deployable Energy Absorber (DEA). Dynamic crush tests of th...

E. L. Fasanella K. E. Jackson M. A. Polanco M. S. Annett

2012-01-01

276

Radarabsorberande Material: En Oeversikt (Radar Absorbing Materials: An Overview).  

National Technical Information Service (NTIS)

The report discusses the present state of knowledge of radar absorbing materials (RAM). In particular, the possibility to make thin absorbents that are efficient in a wide frequency band is discussed. The properties of two types of materials, polymers and...

P. O. Olsson

1995-01-01

277

Experiment research on MM wavelength radar absorbing materials  

Microsoft Academic Search

Experiments to obtain high quality millimeter wavelengths radar absorbing materials are discussed. In order to obtain the best mixing proportion of materials, a great number of materials had been investigated. Several absorbing coating materials achieving this aim are found

Chen ZhiPing; Zhu Qi; Xu Shan-Jia

1999-01-01

278

21 CFR 878.4830 - Absorbable surgical gut suture.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 false Absorbable surgical gut suture. 878.4830 Section 878...DEVICES GENERAL AND PLASTIC SURGERY DEVICES Surgical Devices § 878.4830 Absorbable surgical gut suture. (a) Identification....

2013-04-01

279

21 CFR 878.4840 - Absorbable polydioxanone surgical suture.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 false Absorbable polydioxanone surgical suture. 878.4840 Section 878... GENERAL AND PLASTIC SURGERY DEVICES Surgical Devices § 878.4840 Absorbable polydioxanone surgical suture. (a) Identification....

2013-04-01

280

?-Cyclodextrin-based oil-absorbent microspheres: preparation and high oil absorbency.  

PubMed

This article reports the preparation and evaluation of polymeric microspheres as a new class of oil-absorbent (POAMs). Based on our earlier oil-absorbents, the present microspheres contained ?-cyclodextrin (?-CD) moieties as both cross-linking agent and porogen agent, and showed exciting high oil absorbency, fast oil absorption speed and good reusability. Such microspheres were prepared via suspension polymerization with octadecyl acrylate and butyl acrylate as co-monomers, ?-CD derivative as cross-linking agent, 2,2'-azoisobutyronitrile as initiator and polyvinylalcohol as stabilizer. Oil absorbency of the POAMs was, for CCl(4), 83.4; CHCl(3), 75.1; xylene, 48.7; toluene, 42.8; gasoline, 30.0; kerosene 27.1; and diesel, 18.2 g/g (oil/POAMs). Saturation oil absorption reached within 3h in CCl(4). The POAMs exhibited high oil retention percentage (>90%), and can be reused for at least 10 times while keeping oil absorbency almost unchanged. PMID:23044125

Song, Ci; Ding, Lei; Yao, Fei; Deng, Jianping; Yang, Wantai

2012-08-17

281

14 CFR 27.475 - Tires and shock absorbers.  

Code of Federal Regulations, 2013 CFR

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

2013-01-01

282

14 CFR 29.475 - Tires and shock absorbers.  

Code of Federal Regulations, 2010 CFR

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

2010-01-01

283

14 CFR 29.475 - Tires and shock absorbers.  

Code of Federal Regulations, 2010 CFR

...2009-01-01 2009-01-01 false Tires and shock absorbers. 29.475 Section 29.475... Ground Loads § 29.475 Tires and shock absorbers. Unless otherwise prescribed...assumed to be in their static position and the shock absorbers to be in their most critical...

2009-01-01

284

14 CFR 27.475 - Tires and shock absorbers.  

Code of Federal Regulations, 2010 CFR

...2009-01-01 2009-01-01 false Tires and shock absorbers. 27.475 Section 27.475... Ground Loads § 27.475 Tires and shock absorbers. Unless otherwise prescribed...assumed to be in their static position and the shock absorbers to be in their most critical...

2009-01-01

285

14 CFR 27.475 - Tires and shock absorbers.  

Code of Federal Regulations, 2010 CFR

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

2010-01-01

286

14 CFR 29.475 - Tires and shock absorbers.  

Code of Federal Regulations, 2013 CFR

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

2013-01-01

287

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

288

Electrical tree initiation in polyethylene absorbing Penning gas  

Microsoft Academic Search

AC tree initiation voltage was examined in untreated LDPE, vacuum degassed LDPE and LDPE absorbing He gas (He gas was absorbed after vacuum degassing). The authors have already reported that vacuum degassed LDPE shows much higher tree initiation voltage than untreated LDPE because of the absence of oxygen. Therefore they expected that LDPE absorbing He would show the same property

N. Shimizu; N. Tohyama; H. Sato

1996-01-01

289

Wet waste flue gas desulfurizing process using lime as absorbent  

Microsoft Academic Search

A wet waste flue gas desulfurizing process using lime as absorbent is disclosed wherein a sulfur oxide-containing waste flue gas is washed with a liquid absorbent containing calcium hydroxide or calcium carbonate for the purpose of removing the sulfur oxide from said waste flue gas, characterized in that an absorbing device is divided into two stages, i.e., a former stage

M. Atsukawa; K. Kamei; N. Shinoda; H. Ushio

1977-01-01

290

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

291

Rotor blade lag damping using embedded chordwise absorbers  

Microsoft Academic Search

The feasibility of helicopter blade lag damping using embedded chordwise absorbers is investigated. The basic feature of this approach is the use of tuned vibration absorbers along the blades. This concept, utilizing a portion of the leading edge weights that are already incorporated into the blade as a part of the mass of the absorbers, may have the potential to

Hao Kang

2001-01-01

292

DAMPED LYalpha ABSORBER KINEMATICS AND OUTFLOWS FROM STARBURST GALAXIES  

SciTech Connect

We present results from a numerical study of the multiphase interstellar medium in sub-Lyman-break galaxy protogalactic clumps. Such clumps are abundant at z = 3 and are thought to be a major contributor to damped Lyalpha absorption. We model the formation of winds from these clumps and show that during star formation (SF) episodes they feature outflows with neutral gas velocity widths up to several hundred km s{sup -1}. Such outflows might, in principle, produce the high velocity dispersion observed in damped Lyalpha absorbers (DLAs). Since the majority of DLAs have low SF rates, and only a small fraction of them might host a starburst at any given time, our median velocity width v {sub 90} still falls short of the observed value. This discrepancy with observations could indicate that at l = 12 pc grid resolution the efficiency of conversion of feedback energy into hydrodynamical flows is less than optimal, even though these models show a remarkable improvement compared to the lower resolution runs. At l = 24 pc, the first signs of the multiphase medium are spotted; however, at this low resolution thermal injection of feedback energy cannot yet create hot expanding bubbles around star-forming regions-instead feedback tends to erase high-density peaks and suppress SF. At l = 12 pc, we see the formation of cold (approx<300 K), dense (approx>100 M {sub sun} pc{sup -3}) clouds that maintain SF while being compressed by the hot medium; at the same time a large fraction of feedback energy is channeled into low-density bubbles and winds. These winds often entrain compact neutral clumps which produce multi-component metal absorption lines.

Razoumov, Alexei O., E-mail: razoumov@ap.smu.c [Institute for Computational Astrophysics, Department of Astronomy and Physics, Saint Mary's University, Halifax, NS, B3H 3C3 (Canada)

2009-12-10

293

Cold fronts in galaxy clusters  

NASA Astrophysics Data System (ADS)

Context. Cold fronts have been observed in several galaxy clusters. Understanding their nature and origin is extremely important for investigating the internal dynamics of clusters. Aims: To gain insight into the nature of these features, we carry out a statistical investigation of their occurrence in a sample of galaxy clusters observed with XMM-Newton and correlate this occurrence with different cluster properties. Methods: We selected a sample of 45 clusters starting from the B55 flux limited sample (Edge et al. 1990, MNRAS, 245, 559) and performed a systematic search for cold fronts. Results: We find that a large fraction of clusters host at least one cold front. Cold fronts are easily detected in all systems that are manifestly undergoing a merger event in the plane of the sky, while the presence of these features in the remaining clusters is related to a steep entropy gradient, in agreement with theoretical expectations. Assuming that cold fronts in cool core clusters are triggered by minor merger events, we estimate a minimum of 1/3 merging events per halo per Gyr. Appendix is only available in electronic form at http://www.aanda.org

Ghizzardi, S.; Rossetti, M.; Molendi, S.

2010-06-01

294

[Performance of desulfurizing absorbent of roasted navajoite].  

PubMed

An innovative flue gas desulfurization (FGD) coupling process was proposed in this study to overcome the problems in wet-type limestone/lime processes which include fouling, clogging, and difficulty of selling the by-products and the problems in traditional process for vanadium extraction from navajoite ore such as excessive consumption of sulfuric acid and emissions of pollutants. The performance of a jet bubbling reactor (JBR) at pilot-scale was evaluated using navajoite ore produced in the process of extracting vanadium pentoxide as desulfurization absorbent. Results showed that navajoite ore slurry achieved better desulfurization performance than limestone slurry. When the inlet flue gas pressure drop was 3.0 kPa, the gas flow was about 2350 m3 x h(-1) and the pH of the navajoite ore slurry was higher than 4.5, the desulfurization efficiency was stable about 90%. The SO2 removal efficiency appeared to increase along with the increasing of absorbent cycle-index. The efficiency of the second circulation was improved 3.5% compared to the first circulation. After an operating duration of 40 minutes, the leaching rate of vanadium pentoxide was about 20%, and reached 60% when the by-products were leached with 5% dilute sulfuric acid for 10 hours. The by-product from this process not only could be used to produce vanadium pentoxide which is a valuable industrial product, but also could significantly overcome the pollution problem existing in the traditional refining process of vanadium pentoxide when navajoite ore is used as the feed material. This FGD process using roasted navajoite slurry as absorbent is environmental sound and cost-effective, and shows the potential for application in the field of flue gas desulfurization as well as hydrometallurgy. PMID:20527168

Chen, Fang; Yang, Chun-ping; Gan, Hai-ming; Wu, Ting; Chen, Hai-lin; Chen, Hong; Xu, Ke-hui; Xie, Geng-xin

2010-04-01

295

Flexor Tenorrhaphy Using Absorbable Suture Materials  

PubMed Central

Background Nonabsorbable sutures are favorable for repairing flexor tendons. However, absorbable sutures have performed favorably in an animal model. Methods Two-strand sutures using the interlocking modified Kessler method with polydioxanone absorbable sutures 4-0 were used to repair completely ruptured flexor tendons in 55 fingers from 41 consecutive patients. The medical records of average 42 follow up weeks were analyzed retrospectively. The data analyzed using the chi-squared test, and Fisher's exact test was used for postoperative complications. The results were compared with those of other studies. Results Among the index, middle, ring, and little fingers were injured in 9, 17, 16, and 13 fingers, respectively. The injury levels varied from zone 1 to 5. Of the 55 digits in our study, there were 26 (47%) isolated flexor digitorum profundus (FDP) injuries and 29 (53%) combined FDP and with flexor digitorum superficialis injuries. Pulley repair was also conducted. Concomitant injuries of blood vessels and nerves were found in 17 patients (23 fingers); nerve injuries occurred in 5 patients (10 fingers). Two patients had ruptures (3.6%), and one patient had two adhesions (3.6%). Using the original Strickland criteria, all the patients were assessed to be excellent or good. Also, fibrosis and long-term foreign body tissue reactions such as stitch granuloma were less likely occurred in our study. Compared to the Cullen's report that used nonabsorbable sutures, there was no significant difference in the rupture or adhesion rates. Conclusions Therefore, this study suggests that appropriate absorbable core sutures can be used safely for flexor tendon repairs.

Kang, Hyung Joo; Kim, Jin Soo; Ki, Sae Hwi; Roh, Si Young; Yang, Jae Won

2012-01-01

296

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

297

Absorbing filter to flatten gaussian beams.  

PubMed

An absorbing filter that flattens the Gaussian intensity profile of a laser beam has been developed. The filter was fabricated by dc magnetron sputtering a thin tantalum film, by using a combination of substrate masking and motion. A model of the filter production has been developed that successfully predicts the film profile and performance. A typical filter produced by using these techniques results in a flat output to within +/-3% over a 2.2 mm with a transmission of 60% of the peak intensity of the Gaussian beam. PMID:20725305

Dew, S K; Parsons, R R

1992-06-20

298

Cold Roller-Compacted Concrete for Roads and Hardstands on Army Installations in Cold Regions.  

National Technical Information Service (NTIS)

Cold roller compacted concrete (Cold-RCC) is the result of merging the RCC paving technology with Cold Weather Admixture Systems (CWAS) technology. It extends the use of RCC paving beyond the traditional construction season. A laboratory investigation was...

C. Smith E. Cortez L. Barna T. Peltz

2010-01-01

299

Properties of Propagation of Electromagnetic Wave in a Multilayer Radar-Absorbing Structure With Plasma and Radar-Absorbing Material  

Microsoft Academic Search

A multilayer radar-absorbing structure with plasma- and radar-absorbing material (RAM) is established to investigate the stealth mechanisms of the multilayer absorber. The method of impedance transformation with multiple dielectrics is used to analyze the propagation of electromagnetic (EM) waves in the multilayer structure. The dependences of EM waves attenuation on the parameters of the plasma and RAMs are provided. The

Cheng-Xun Yuan; Zhong-Xiang Zhou; Jingwen W. Zhang; Xiao-Li Xiang; Yue Feng; Hong-Guo Sun

2011-01-01

300

A novel structure for tunable terahertz absorber based on graphene.  

PubMed

Graphene can be used as a platform for tunable absorbers for its tunability of conductivity. In this paper, we proposed an "uneven dielectric slab structure" for the terahertz (THz) tunable absorber based on graphene. The absorber consists of graphene-dielectric stacks and an electric conductor layer, which is easy to fabricate in the manufacturing technique. Fine tuning of the absorption resonances can be conveniently achieved by adjusting the bias voltage. Both narrowband and broadband tunable absorbers made of this structure are demonstrated without using a patterned graphene. In addition, this type of graphene-based absorber exhibits stable resonances with a wide range angles of obliquely incident electromagnetic waves. PMID:24104291

Xu, Bing-Zheng; Gu, Chang-Qing; Li, Zhuo; Niu, Zhen-Yi

2013-10-01

301

Front-end Combination Component Of Fixed Mask And Absorber  

SciTech Connect

A front-end combination component of fixed mask and absorber is a device that combines a fixed mask and a photon absorber in one body to save space, setup work and maintenance in the photon beamline front-end. The SPring-8 undulator absorber consists of an upper V-shaped photon absorber part and a lower rectangular beam-transfer channel part. The upper wall of the beam-transfer channel is cut in the V-shape notch as the photon absorber. The combination component design based on the absorber is adopted. The photon duct part is modified in the shape of the fixed mask. The combination component moves up and down. In the upper limit, it acts as the mask and the beam-transfer channel. In the lower limit, it acts as the photon absorber. Design details of the component and its commissioning are presented.

Mochizuki, Tetsuro; Takahashi, Sunao [SPring-8/JASRI, 1-1-1, Kouto, Mikazuki-cho, Sayo-gun, Hyogo 679-5198 (Japan); Kitamura, Hideo [SPring-8/JASRI, 1-1-1, Kouto, Mikazuki-cho, Sayo-gun, Hyogo 679-5198 (Japan); SPring-8/RIKEN, 1-1-1, Kouto, Mikazuki-cho, Sayo-gun, Hyogo 679-5148 (Japan)

2004-05-12

302

Phase-shifting effect of thin-absorber EUV masks  

NASA Astrophysics Data System (ADS)

Phase-shifting effect of EUV masks with various absorber thicknesses has been studied both by simulations and experiments. In EUV lithography, masks with 180 phase shifting absorber work like embedded attenuated phase-shifting masks. At 66nm thickness of TaN/TaON absorber, 180 degree phase shifting can be achieved in theory. Based on the experiments, we observed that the true180 degree phase shifting can be achieved with absorber thickness between 66 and 76 nm. In this paper, phase shifting impact of the various thickness absorbers has been characterized. Imaging performance of masks with 51 nm, 66 nm and 76 nm thick absorber has been experimentally compared. The process window of various thickness absorber masks are rigorously studied.

Tanabe, Hiroyoshi; Murachi, Tetsunori; Lee, Sang H.; Chandhok, Manish; Park, Seh-Jin; Zhang, Guojing; Abe, Tsukasa; Ogase, Taichi; Hayashi, Naoya

2011-10-01

303

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

304

Numerical study of metamaterial absorber and extending absorbance bandwidth based on multi-square patches  

Microsoft Academic Search

A simple design of metamaterial absorber (MA) was proposed based on a periodic array of metal patch at microwave frequencies. Our design could exhibit absorption of 99.9% confirmed by numerical simulation. Such high narrowband absorption which mainly based on strong electric and magnetic resonances overlapping in a certain frequency range and perfect impedance-matched ( z = 1) to the free

H. Luo; Y. Z. Cheng; R. Z. Gong

2011-01-01

305

Sagnac interferometry with cold atoms  

Microsoft Academic Search

Summary form only given. Matter wave interferometers have become very promising tools in fundamental physics and metrology. The sensitivities obtained with such atomic quantum sensors compete with classical state-of-the-art devices for acceleration and rotation measurements. Currently, we are setting up a new cold atom Sagnac interferometer (CASI) to realize high precision measurements of rotations with a compact and flexible setup.

C. Jentsch; S. Chelkowski; E. M. Rasel; W. Ertmer

2003-01-01

306

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...

307

Cold panniculitis in a neonate  

Microsoft Academic Search

Symmetric areas of erythema and induration developed on the cheeks of a 17-day-old black girl after ice packs were applied to her face for treatment of supraventricular tachycardia. To our knowledge, this is the first report of cold panniculitis caused by treatment of a cardiac arrhythmia with ice packs.

Jon C Ter Poorten; Adelaide A Hebert; Roma Ilkiw

1995-01-01

308

Cold panniculitis in a neonate.  

PubMed

Symmetric areas of erythema and induration developed on the cheeks of a 17-day-old black girl after ice packs were applied to her face for treatment of supraventricular tachycardia. To our knowledge, this is the first report of cold panniculitis caused by treatment of a cardiac arrhythmia with ice packs. PMID:7615891

Ter Poorten, J C; Hebert, A A; Ilkiw, R

1995-08-01

309

Cold Water Near-Drowning.  

National Technical Information Service (NTIS)

The workbook is for people who have occasion to be on the water in Alaska. The information presented on cold water near-drowning and cardiopulmonary resuscitation (CPR) represents only a general approach to these subjects. Some additional sources are list...

1990-01-01

310

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

311

Cold Denaturation of Staphylococcal Nuclease  

Microsoft Academic Search

Denaturation of staphylococcal nuclease was studied in a temperature range from -7 to 70 degrees C by scanning microcalorimetry and spectropolarimetry. It was found that the native protein is maximally stable at about 20 degrees C and is denatured upon heating and cooling from this temperature. The heat and cold denaturation processes are approximated rather well by a two-state transition

Yuri V. Griko; Peter L. Privalov; Julian M. Sturtevant; Sergey Yu. Venyaminov

1988-01-01

312

Cold War Geopolitics: Embassy Locations.  

ERIC Educational Resources Information Center

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

Vogeler, Ingolf

1995-01-01

313

A New Cold Sterilization Unit.  

National Technical Information Service (NTIS)

The reasons for an absolutely reliable cold sterilization method are outlined. Experience with a new sterilization unit operating with ethylene oxide under tension, operating at 5.5 atmospheres and 55 C is discussed. The device can also be used for packag...

M. Schmidt-mende W. Heiss

1976-01-01

314

Compressibility of cold catalyzed matter  

Microsoft Academic Search

The properties of cold catalyzed matter (CCM) of density near and above the density characteristic of the central region of heavy atomic nuclei are of fundamental importance for the physics of neutron stars. In this paper the compression modulus of CCM (an electrically neutral, spatially homogeneous mixture of electrons, neutrons, and protons at a temperature of 0 K) is studied

P. Haensel

1980-01-01

315

Gating ratchet for cold atoms.  

PubMed

We demonstrate experimentally a gating ratchet with cold rubidium atoms in a driven near-resonant optical lattice. A single-harmonic periodic modulation of the optical potential depth is applied, together with a single-harmonic rocking force. Directed motion is observed as a result of the breaking of the symmetries of the system. PMID:18352250

Gommers, R; Lebedev, V; Brown, M; Renzoni, F

2008-01-30

316

On Future European Cold Spells  

NASA Astrophysics Data System (ADS)

Many studies exist that show that in a warming future climate, European winter cold spells will become less frequent, less intense, and less persistent. Indeed, many metrics like, the annual number of frost days, the number of ice days, and winter heating degree days (known from the energy sector) do show significant negative trends. Yet the anomalous circulations that lead to the cold spells appear not to show such strong negative trends. With advection being the most important source for temperature variability at mid-latitudes, and especially for Western Europe, this brings forward the idea that the non-uniform pattern of global warming itself, and the modification of the mean (westerly) circulation must be the key-factors to explain the changes in cold-spell statistics. These two factors mainly affect the mean and variance of the winter probability density function. It is shown that many of the future changes in cold-spell statistics are indeed readily explained by taking into account only changes of the (increased) mean and (reduced) variance of the daily winter temperature probability density function.

de Vries, H.; Haarsma, R. J.; Hazeleger, W.

2012-04-01

317

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.

Roth, Jerry; Service, Noaa O.

318

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.

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

2013-01-01

319

Cusps, self-organization, and absorbing states.  

PubMed

Elastic interfaces embedded in (quenched) random media exhibit metastability and stick-slip dynamics. These nontrivial dynamical features have been shown to be associated with cusp singularities of the coarse-grained disorder correlator. Here we show that annealed systems with many absorbing states and a conservation law but no quenched disorder exhibit identical cusps. On the other hand, similar nonconserved systems in the directed percolation class are also shown to exhibit cusps but of a different type. These results are obtained both by a recent method to explicitly measure disorder correlators and by defining an alternative new protocol inspired by self-organized criticality, which opens the door to easily accessible experimental realizations. PMID:19518401

Bonachela, Juan A; Alava, Mikko; Muñoz, Miguel A

2009-05-26

320

Microcellular ceramic foams for radar absorbing structures  

SciTech Connect

This is the final report of a one-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The goal of this project is to develop a lightweight, semi-structural, radar-absorbing ceramic foam that can be incorporated into aircraft exhaust systems to replace many of the currently used dense ceramic parts and thereby improve the radar cross section. Although the conventional processes for producing ceramic foams have not been able to provide materials that meet the design specifications for high strength at low density, we have developed and demonstrated a novel sol-gel emulsion process for preparing microcellular ceramic foams in which compositional and microstructural control is expected to provide the requisite high-temperature radar-absorption, strength-to-weight ratio, and thermal insulative properties.

Huling, J.; Phillips, D.

1996-09-01

321

Synthesis of a new Moessbauer absorber  

SciTech Connect

A method is developed for preparing Mg paraperiodate that consists of the oxidation by ozone of elemental I{sub 2} to iodic acid with subsequent preparation of Mg(IO{sub 3}){sub 2} and thermal decomposition of it to Mg{sub 5}(IO{sub 6}){sub 2}. This method enables semimicrogram quantities of the compound to be used and is directed toward the preparation of a {sup 129}I Moessbauer absorber. X-ray structural data are presented for Mg iodate and paraperiodate. A sample of formula 19MgO{center_dot}Mg{sub 5}(IO{sub 6}){sub 2} is prepared. Preliminary Moessbauer measurements with a source 2MgO{center_dot}Mg{sub 3}{sup 129M}TeO{sub 6} suggests that the paraperiodate has a singlet absorption and a relatively large Debye-Waller factor that depends weakly on temperature.

Grushko, Y.S.; Kokovina, L.A.; Kolesnik, S.N.

1994-07-01

322

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

323

Quasiperiodicity in lasers with saturable absorbers  

SciTech Connect

In this paper, we consider the mean-field equations for the laser with a saturable absorber (LSA) and concentrate on the low-intensity solutions. We show that the LSA equations may admit two successive bifurcations. The first bifurcation corresponds to the transition from the zero-intensity state to time-periodic intensities and is a Hopf bifurcation. The second bifurcation corresponds to the transition from these time-periodic intensities to quasiperiodic intensities which are characterized by two incommensurable frequencies. In order to describe these transitions, we investigate a particular limit of the parameters and propose a new perturbation method for solving the LSA equations. We give analytical conditions for the existence of both the primary and secondary bifurcations.

Erneux, T.; Mandel, P.; Magnan, J.F.

1984-05-01

324

Cold-Weather Sports and Your Family  

MedlinePLUS

... once the weather turns frosty. Beating the Cold-Weather Blahs Once a chill is in the air, ... your kids while being active. Types of Cold-Weather Sports Skiing, snowboarding, ice skating, and snowshoeing are ...

325

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

326

75 FR 52213 - Cold Treatment Regulations  

Federal Register 2010, 2011, 2012, 2013

...temperature before initiating cold treatment. To gain a better understanding...pallets of fruit undergoing cold treatment while in transit. Hot spots...dioxide, a process that generates heat. After 7 days of treatment, fruit respiration can...

2010-08-25

327

Is It a Cold or the Flu?  

MedlinePLUS

... Issue Past Issues Is It a Cold or the Flu? Past Issues / Fall 2006 Table of Contents For ... this page please turn Javascript on. Symptoms Cold Flu ... at the beginning of the illness Stuffy Nose Common Sometimes ...

328

Zinc for Colds: The Final Word?  

MedlinePLUS

... may be reprinted for personal, noncommercial use only. Zinc for colds: The final word? By Mayo Clinic ... share your e-mail address Sign up Question Zinc for colds: The final word? Will taking zinc ...

329

Predictors of Cold Weather Health Behaviors.  

National Technical Information Service (NTIS)

This study screened potential predictors of maladaptive cold weather behaviors. Male Marine Corps volunteers (n = 161) completed questionnaires providing a battery of predictor measures, including: (a) Personal history variables related to cold injuries, ...

R. R. Vickers L. K. Hervig

1984-01-01

330

Physiological Acceptance Criteria for Cold Weather Clothing.  

National Technical Information Service (NTIS)

The purpose of the present investigation was to develop physiological limit criteria for cold weather clothing items which meet the limits for protection against development of a cold injury, and which are also associated with an increased level of subjec...

N. A. Pimental

1991-01-01

331

Clearance of absorbed selenium by the liver  

SciTech Connect

The liver plays a central role in the metabolism of selenium. It secretes plasma selenoproteins, contains a major fraction of the glutathione peroxidase in the body, and synthesizes excretory metabolites. The role of the liver in processing newly absorbed selenium was studied. Male chow-fed rats were fasted overnight and given 24 ng of selenium as {sup 75}SeO{sub 3}{sup 2{minus}} by stomach tube. Animals were exsanguinated at 15, 30, 45, 60, 90, 120, and 180 min after dosing. Comparison of {sup 75}Se uptake by liver, kidney, heart, muscle, testis, brain, and spleen indicated an earlier uptake by liver than by any other tissue. At 15 min, {sup 75}Se in the portal vein blood was 2.6 times that in the hepatic vein blood. Gel filtration analysis suggested a loose association of {sup 75}Se with protein in plasma at 15 min, but immunoprecipitation indicated it was largely in the form of selenoprotein P after 30 min. End-to-side portacaval shunts (PCS) were constructed in rats and sham-operated animals were used as controls. When {sup 75}SeO{sub 3}{sup 2{minus}} was given to animals with PCS, uptake of {sup 75}Se by liver did not precede uptake by other tissues. Also no gradient was detected across the lungs or kidney. {sup 75}Se content of the kidney was higher in PCS rats than in sham-operated rats. This is consistent with removal of the first-pass effect of the liver facilitating uptake of {sup 75}Se by systemic tissues. These results suggest that the preferential uptake of absorbed selenium by the liver is due both to its position in the portal circulation and to an intrinsic high uptake capacity.

Kato, Tatsuko; Read, R.; Rozga, J.; Burk, R.F. (Vanderbilt Univ., Nashville, TN (United States))

1991-03-11

332

Upper airways reactions to cold air  

Microsoft Academic Search

Cold air-induced rhinitis is a common complaint of individuals with chronic allergic or nonallergic rhinitis and those with\\u000a no chronic nasal disease. It is characterized by rhinorrhea, nasal congestion, and nasal burning that appear within minutes\\u000a of exposure to cold air and dissipate soon after exposure is terminated. The symptoms of cold-air rhinitis are reproduced\\u000a experimentally with nasal cold-air provocation.

Alvaro A. Cruz; Alkis Togias

2008-01-01

333

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

334

Two-Photon Cooperative Absorption in Colliding Cold Na Atoms  

NASA Astrophysics Data System (ADS)

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

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

2012-06-01

335

Rotor blade lag damping using embedded chordwise absorbers  

NASA Astrophysics Data System (ADS)

The feasibility of helicopter blade lag damping using embedded chordwise absorbers is investigated. The basic feature of this approach is the use of tuned vibration absorbers along the blades. This concept, utilizing a portion of the leading edge weights that are already incorporated into the blade as a part of the mass of the absorbers, may have the potential to replace current blade lag dampers and reduce complexity, aerodynamic drag, and weight. The effectiveness of the embedded absorbers is evaluated by analyzing and testing blade lag damping and rotor system aeromechanical stability. An aeromechanical stability analysis of the rotor system with embedded chordwise absorbers is developed. The rotor blade is modeled as an elastic beam undergoing axial, flapwise, lagwise, and torsional deflections. The fuselage is modeled as a rigid body with roll and pitch rotations about its center of mass. Each embedded absorber is modeled as a mass-spring pair. The rotor-absorber-fuselage system equations of motion are formulated using Hamilton's Principle and spatially discretized using the finite element method. The modal frequencies and damping of the system are found using complex eigenvalue solutions of the linearized equations. A rigid blade-absorber model is developed to explore the dynamic response of the embedded absorbers, including the static and steady-state dynamic response, and to examine the effect of the embedded absorber on rotor blade aeroelastic stability, including flap-lag flutter, pitch-flap flutter, and pitch divergence. A small-scale model rotor system with embedded absorbers is designed and constructed. A set of experiments measuring blade lag frequency and damping is conducted. The effects of some key issues, including absorber mass, location, and tuning frequency, are examined experimentally. The analytical results are correlated with the experimental data. The theoretical lag frequencies and damping of the blade with embedded absorbers are in good agreement with the experimental data. The aeromechanical stability analysis of the rotor-fuselage system also shows a good agreement with the experimental data. The theoretical and experimental results both show promising blade lag damping augmentation using embedded chordwise absorbers. The blade damping augmentation using embedded chordwise absorber varies from 0.3% to 15% critical damping ratio, depending on blade and absorber parameters. The ground resonance stability analysis of the hingeless rotor system and articulated rotor system shows that the blade lag damping augmentation using embedded chordwise absorbers improves the ground resonance stability. (Abstract shortened by UMI.)

Kang, Hao

336

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

337

Cold Room and Mold Fact Sheet  

Cancer.gov

Biosafety Technical Bulletin:  Cold Rooms and Mold  Low temperatures and limited air movement present ideal conditions for condensation and  moisture build?up, which presents an ideal environment for mold growth in cold rooms.   Improper work practices can quickly lead to surface contamination within a cold room.  

338

Cold Acclimation Can Be Induced in Humans by Repeated Cold Water Immersion.  

National Technical Information Service (NTIS)

The effects of repeated cold water immersion on thermoregulatory responses to cold air were studied in seven males. A cold air stress test (CAST) was performed before and after completion of an acclimation program consisting of daily 90-min cold (18C) wat...

A. J. Young S. R. Muza M. N. Sawka K. B. Pandolf

1986-01-01

339

Development of a Compact Photon Absorber for a Multipole Wiggler  

Microsoft Academic Search

A compact photon absorber for the accelerator diagnosis beamline #2 of the SPring-8 storage ring, which withstands high heat load of the synchrotron radiation from a multi-pole wiggler, has been developed. In order to make the absorber compact, two absorber blocks made of GlidCop with a different tilt angle of surface have been arranged in tandem in the vacuum chamber.

Kazuhiro Tamura; Masaya Oishi; Haruo Ohkuma; Shiro Takano; Mitsuhiro Masaki; Tetsuhiko Yorita

2006-01-01

340

Large area bismuth absorbers for X-ray microcalorimeters  

Microsoft Academic Search

Two challenges facing the use of large area (2mm×2mm) bismuth absorbers for microcalorimetry are uncertainties in the heat capacity of bismuth and the effects of lateral heat conduction and position dependence due to the absorber's large size. We have measured the heat capacity of three Bi samples to be 0.3?0.6JK?1m?3 at 100mK. These absorbers also exhibit response variations as phonons

J. E Vaillancourt; C. A Allen; R. Brekosky; A. Dosaj; M. Galeazzi; R. Kelley; D. Liu; D. McCammon; F. S Porter; L. E Rocks; W. T Sanders; C. K Stahle

2004-01-01

341

Laser mode locking using a saturable absorber incorporating carbon nanotubes  

Microsoft Academic Search

This paper describes a new class of saturable absorber device based on single-wall carbon nanotube (SWNT)-the saturable absorber incorporating nano tube (SAINT). The device possesses ultrafast optical properties comparable to that of the industrial standard semiconductor saturable absorber mirror (SESAM). Passively mode-locked picosecond fiber lasers in different configurations are demonstrated using SAINTs as mode lockers. This is the first demonstration

Sze Y. Set; Hiroshi Yaguchi; Yuichi Tanaka; Mark Jablonski

2004-01-01

342

A simple measuring method of reflectivity for radar absorbing material  

Microsoft Academic Search

The basic principle of measuring reflectivity for radar absorbing material (RAM) is analyzed. And a simple method for measuring reflectivity of radar absorbing material using vector network analyzer HP8722ET and APC-7mm coaxial line is presented. The results indicate that the reflectivity of the radar absorbing material can be measured in 0.05-18 GHz using this method. Under the ordinary laboratory condition,

Feng Yongbao; Qiu Tai; Shen Chunying; Li Xiaoyun

2005-01-01

343

FUNDAMENTALS OF DOSIMETRY BASED ON ABSORBED-DOSE STANDARDS  

Microsoft Academic Search

This chapter reviews the fundamentals of radiation dosimetry needed to do reference dosimetry for external beam radiotherapy when starting from an ion chamber calibrated in terms of absorbed-dose to water. It briefly reviews the status of primary standards for absorbed dose to water. The kQ formalism developed to utilize these absorbed-dose calibration factors is described for use in electron and

D. W. O. Rogers

344

Absorbing boundaries in the mean-field approximation  

SciTech Connect

Absorbing boundaries in the mean-field approximation are investigated and applied to small systems interacting with strong laser fields. Two types of calculations are considered: (i) a variational approach with a complex absorbing potential included in the full Hamiltonian and (ii) the inclusion of a complex absorbing potential in the single-particle equations. It is elucidated that the second approach outperforms the variational approach for small grids.

Jhala, Chirag; Dreissigacker, Ingo; Lein, Manfred [Institut fuer Theoretische Physik and Centre for Quantum Engineering and Space-Time Research (QUEST), Leibniz Universitaet Hannover, Appelstrasse 2, D-30167 Hannover (Germany)

2010-12-15

345

Solar energy applications for heat-absorbing glass  

Microsoft Academic Search

Commercially-available infrared-absorbing glass transmits over 70% of the visible part of the solar spectrum and absorbs nearly 100% of the infrared. The application of such glass to solar energy production has been suggested as the composition of the heat-absorbing glass may be adapted for various applications. Such applications include: (1) liquid collectors, where the collector consists of a glass-panel structure

C. Deminet

1977-01-01

346

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

347

Markaryan 277: a clumpy irregular galaxy  

SciTech Connect

The results are given of a densitometric and detailed spectrophotometric study of the galaxy Mark. 277. The observational material was obtained with the Zeiss-600 and 6-m reflecting telescope of the Special Astro-physical Observatory. In Mark. 277 there are four condensations with spectra characteristic of giant H II regions. The physical conditions in them correspond to those for normal H II regions, and a metal deficit is observed in the chemical composition. It is concluded that Mark. 277 consists of four clumps, these being H II complexes with a metal deficit.

Andreasyan, N.K.; Burenkov, A.N.; Khachikyan, E.E.

1988-01-01

348

Clumpy Molecular Hydrogen in the Dumbbell Nebula  

NASA Astrophysics Data System (ADS)

We present a high resolution image of the planetary nebula NGC 6853 (the Dumbbell Nebula) in the 2.122?m narrow band, which corresponds to the molecular hydrogen (H2) rotational vibration line, v = 1 ? 0 S(1). The image was obtained from the Subaru 8.2m telescope atop Mauna Kea, Hawaii. Seeing for this observation was 0.49”, which is good enough to observe fine details in the distribution of molecular hydrogen throughout the nebula with specific emphasis on H2 in cometary knots. Cometary knots present themselves as excellent cosmic laboratories for studying the chemistry of planetary nebulae and their role in the repopulation of dust and molecules to the interstellar medium (ISM). The distribution and shape of the knots are analyzed and compared with optical images of the Dumbbell as well as with previous surveys of H2 in the Helix and Ring nebulae. It is found that cometary knots observed by Hubble in optical wavelengths are all associated with H2 emission. Observations of ionized gas show both localized and diffuse distribution, while molecular gas seems limited to survive primarily in clumps. When compared to the Helix, the knots in the dumbbell are less well-defined, which could signify an age difference or simply be a projection effect due to opposite viewing angles. It is also noteworthy that observations of the Helix, while of similar seeing, provide much better detail due to being half the distance of the Dumbbell.

Baldridge, Sean; Speck, A.; Matsuura, M.; Jacoby, G.

2013-01-01

349

Numerical study of metamaterial absorber and extending absorbance bandwidth based on multi-square patches  

Microsoft Academic Search

A simple design of metamaterial absorber (MA) was\\u000a proposed based on a periodic array of metal patch at microwave frequencies.\\u000a Our design could exhibit absorption of 99.9% confirmed by numerical\\u000a simulation. Such high narrowband absorption which mainly based on strong\\u000a electric and magnetic resonances overlapping in a certain frequency range\\u000a and perfect impedance-matched (z = 1) to the free space.

H. Luo; Y. Z. Cheng; R. Z. Gong

350

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

351

Absorbable pin: a new method of fixation for digital arthrodesis.  

PubMed

A new method of fixation of digital arthrodesis is being used at Atlanta Hospital. A total of 58 digits have been arthrodesed at the proximal interphalangeal joint using absorbable pin fixation. The technique of absorbable pin insertion, as well as the advantages and disadvantages, are discussed in this article. Infection, foreign body reaction, vascular compromise, or excessive swelling and edema were not evident in any of the 58 digits reviewed. The internal absorbable pin fixation is considered a viable alternative to previous forms of fixation for digital arthrodesis. The absorbable pin previously has been used for osteochondral fractures of the knee. PMID:2338471

Patton, G W; Shaffer, M W; Kostakos, D P

352

Optimal active vibration absorber: Design and experimental results  

NASA Astrophysics Data System (ADS)

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.

1992-12-01

353

Absorbing boundary condition for Bloch–Floquet eigenmodes  

NASA Astrophysics Data System (ADS)

We present an absorbing boundary condition for electromagnetic frequency domain simulations of photonic crystals and metamaterials. This boundary condition can simultaneously absorb multiple Bloch-Floquet eigenmodes of a periodic crystal, including both propagating and evanescent modes. The photonic crystal or metamaterial in question can include lossy, active, anisotropic and even bi-anisotropic inclusions. The absorbing boundary condition is dependent on an orthogonality condition for Bloch-Floquet eigenmodes, a generalized version of which is presented here. We test this absorbing boundary condition numerically and present the results.

Fietz, Chris

2013-10-01

354

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

Microsoft Academic Search

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

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

2008-01-01

355

Medical problems from cold exposure  

SciTech Connect

Problems resulting from cold exposure can be successfully treated when a coordinated emergency medical transport system and appropriate equipment are available, as well as medical personnel knowledgeable in the management of frostbite and hypothermia. Clinical suspicion of these disorders is essential. Profoundly hypothermic individuals with no recordable vital signs have been resuscitated after controlled, rapid rewarming measures and the use of emergency life-support systems.

Dembert, M.L.

1982-01-01

356

Dismantling the Cold War economy  

Microsoft Academic Search

End-of-the-Cold-War economic realities include political jockeying over the future of weapons systems, a paucity of meaningful conversion efforts, and a suspicion that a weak economy will be unable to compensate for the loss of jobs and purchasing power as defense budgets are reduced. The authors of this book present three interrelated hypotheses: The first is that the existence of a

A. Markusen; J. Yudkin

1992-01-01

357

Hot and Cold Ideal Gases  

NSDL National Science Digital Library

The EJS Hot and Cold Ideal Gases model simulates the mixing of hot and cold two-dimensional ideal gases in a square box. This simulation can be used as part of the activity described in "The Statistical Interpretation of Entropy: An Activity" by Todd Timberlake, to be published in The Physics Teacher. In the model, one gas is initially confined to the left side of the box while the other gas is confined to the right side. An animation window shows the motion of the particles in the box, while an optional graph window plots the temperature of each side of the box, which is determined by measuring the average KE of the particles on each side. The initial number of particles and temperature on each side of the square can be changed and a button allows the user to reverse the particle velocities at any time. The user can modify this simulation if EJS is installed locally by right-clicking within the plot and selecting "Open Ejs Model" from the pop-up menu item. EJS Hot and Cold Ideal Gases model was created using the Easy Java Simulations (EJS) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_entropy_HotAndColdIdealGases.jar file will run the program if Java is installed. EJS is a part of the Open Source Physics Project and is designed to make it easier to access, modify, and generate computer models. Additional EJS models are available. They can be found by searching ComPADRE for Open Source Physics, OSP, or EJS.

Timberlake, Todd

2010-07-01

358

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

359

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

360

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

361

Physiological characteristics of cold acclimatization in man  

NASA Astrophysics Data System (ADS)

Studies were conducted on 15 healthy young soldiers to evaluate the effect of a cold acclimatization schedule on the thermoregulatory and metabolic activity on exposure to acute cold stress. These men were exposed to cold (10‡C) for 4 h daily wearing only shorts for 21 days, in a cold chamber. They were subjected to a standard cold test at 10 ± 1‡C the day 1, 6, 11 and 21. The subjects were made to relax in a thermoneutral room (26 28‡C) for 1 h and their heart rate, blood pressure, oxygen consumption, oral temperature, mean skin temperature, mean body temperature, peripheral temperatures, and shivering activity were recorded. Then they were exposed to 10‡C and measurements were repeated at 30 min intervals, for 2 h. The cold induced vasodilatation (CIVD), cold pressor response and thermoregulatory efficiency tests were measured initially and at the end of acclimatization schedule. The data show that the procedure resulted in elevated resting metabolism, less fall in body temperature during acute cold stress, reduction in shivering, improvement in CIVD and thermoregulatory efficiency and less rise in BP and HR during cold pressor response. The data suggest the possibility of cold acclimatization in man by repeated exposure to moderately severe cold stress.

Mathew, Lazar; Purkayastha, S. S.; Jayashankar, A.; Nayar, H. S.

1981-09-01

362

Calorimetric particle detectors with superconducting absorber materials  

NASA Astrophysics Data System (ADS)

Massive superconducting absorbers of molybdenum and vanadium are used as low temperature calorimeter particle detectors. The high temperature resolution of the thermometry system, consisting of a superconducting phase transition thermometer monitored with a DC Squid, enables the detection of alpha particles with large single crystals. With a 35 g molybdenum single crystal, an energy resolution of 10 percent Full Width Half Maximum (FWHM) on 5.8 MeV alpha particles is obtained. The observed temperature rise of 1.2 mK is a factor of eight less than expected from the calculated heat capacity. Using a 15g vanadium single crystal, the energy resolution in 5.8 MeV alpha particles is 1.2 percent FWHM. In this case, the pulse height is a factor of five smaller than expected from the calculated heat capacity. A possible reason for the large deviations from the expected heat capacity is the presence of hydrogen dissolved in these transition metals, another reason might be the presence of surface impurities or defects.

Forster, G.; Ferger, P.; Feilitzsch, F. V.; Moessbauer, R. L.; Azgui, F.; Igalson, J.

1991-11-01

363

Magnetorheological elastomers in tunable vibration absorbers  

NASA Astrophysics Data System (ADS)

Filling an elastomeric material with magnetizable particles leads to mechanical properties -shear moduli, tensile moduli, and magnetostriction coefficients - that are reversibly and rapidly controllable by an applied magnetic field. The origin of the field dependence of these properties is the existence of field-induced dipole magnetic forces between the particles. These 'smart' composites, which are sometimes termed magnetorheological (MR) elastomers, have been explored for use in a number of components, including automotive suspension bushings. In these and other applications, the tunability of the stiffness can enhance the compliance-control or vibration-transfer performance of the complex mechanical systems in which they are used. In the present study, we have constructed a simple one-degree-of-freedom mass-spring system - an adaptive tuned vibration absorber - that utilizes MR elastomers as variable-spring-rate elements. This device was used not only to explore the performance of such tunable components, but also to extend measurements of the shear moduli of these materials to higher frequencies than has previously been reported. We find that the field-induced increase in moduli of these materials is effective to mechanical frequencies well above 1 kHz, and that the moduli are consistent with the behavior expected for filled elastomers.

Ginder, John M.; Schlotter, William F.; Nichols, Mark E.

2001-07-01

364

Venus glory and the unknown uv absorber  

NASA Astrophysics Data System (ADS)

We report on the first observation of a complete glory on top of the Venus clouds captured with the Venus Monitoring Camera (VMC) when the Sun was almost directly behind the Venus Express space-craft. The wavelengths dependence of the position of the glory is consistent with clouds being composed of spherical droplets of sulphuric acid with radius of 1.2 micron, the so called mode-2 particles. The ratio of backscattering (zero phase angle) to maximum intensity of the glory as well the slope of the observed intensity at larger phase angles cannot be explained by the sulphuric acid droplets alone suggesting a need of an additional component.We investigated several possibilities and argue that one good explanation is that the acid droplets nucleate on small inner cores composed of iron chloride. Iron chloride is one candidate for the so-called unknown absorber in the ultraviolet wavelengths range. An alternate explanation could be that the sulphuric acid droplets are coated with a thin layer of sulphur.

Markiewicz, Wojciech; Almeida, Miguel; Limaye, Sanjay; Ignatiev, Nikolay; Petrova, Elena; Shalygina, Oksana; Titov, Dmitrij

2012-07-01

365

Venus glory and the unknown uv absorber  

NASA Astrophysics Data System (ADS)

We report on the first observation of a complete glory on top of the Venus clouds captured with the Venus Monitoring Camera (VMC) when the Sun was almost directly behind the Venus Express space-craft. The wavelengths dependence of the position of the glory is consistent with clouds being composed of spherical droplets of sulphuric acid with radius of 1.2 micron, the so called mode-2 particles. The ratio of backscattering (zero phase angle) to maximum intensity of the glory as well the slope of the observed intensity at larger phase angles cannot be explained by the sulphuric acid droplets alone suggesting a need of an additional component. We investigated several possibilities and argue that one good explanation is that the acid droplets nucleate on small inner cores composed of iron chloride. Iron chloride is one candidate for the so-called unknown absorber in the ultraviolet wavelengths range. An alternate explanation could be that the sulphuric acid droplets are coated with a thin layer of sulphur.

Markiewicz, W. J.; Petrova, E.; Shalygina, O.; Almeida, M.; Titov, D. V.; Limaye, S. S.; Ignatiev, N.

2012-04-01

366

A variable passive low-frequency absorber  

NASA Astrophysics Data System (ADS)

Multi-purpose concert halls face a dilemma. They can host classical music concerts, rock concerts and spoken word performances in a matter of a short period. These different performance types require significantly different acoustic conditions in order to provide the best sound quality to both the performers and the audience. A recommended reverberation time for classical music may be in the range of 1.5-2 s for empty halls, where rock music sounds best with a reverberation time around 0.8-1 s. Modern rhythmic music often contains high levels of sound energy in the low frequency bands but still requires a high definition for good sound quality. Ideally, the absorption of the hall should be adjustable in all frequency bands in order to provide good sound quality for all types of performances. The mid and high frequency absorption is easily regulated, but adjusting the low-frequency absorption has typically been too expensive or requires too much space to be practical for multi-purpose halls. Measurements were made on a variable low-frequency absorber to develop a practical solution to the dilemma. The paper will present the results of the measurements as well as a possible design.

Larsen, Niels Werner; Thompson, Eric R.; Gade, Anders Christian

2005-04-01

367

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

368

Absorbing state phase transitions with quenched disorder  

NASA Astrophysics Data System (ADS)

Quenched disorder—in the sense of the Harris criterion—is generally a relevant perturbation at an absorbing state phase transition point. Here using a strong disorder renormalization group framework and effective numerical methods we study the properties of random fixed points for systems in the directed percolation universality class. For strong enough disorder the critical behavior is found to be controlled by a strong disorder fixed point, which is isomorph with the fixed point of random quantum Ising systems. In this fixed point dynamical correlations are logarithmically slow and the static critical exponents are conjecturedly exact for one-dimensional systems. The renormalization group scenario is confronted with numerical results on the random contact process in one and two dimensions and satisfactory agreement is found. For weaker disorder the numerical results indicate static critical exponents which vary with the strength of disorder, whereas the dynamical correlations are compatible with two possible scenarios. Either they follow a power-law decay with a varying dynamical exponent, like in random quantum systems, or the dynamical correlations are logarithmically slow even for a weak disorder. For models in the parity conserving universality class there is no strong disorder fixed point according to our renormalization group analysis.

Hooyberghs, Jef; Iglói, Ferenc; Vanderzande, Carlo

2004-06-01

369

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 pK(h) 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

2010-10-01

370

Ultimate cold-electron bolometer with strong electrothermal feedback  

NASA Astrophysics Data System (ADS)

A novel concept of the Cold-Electron Bolometer (CEB) with strong electrothermal feedback has been proposed. The concept is based on direct electron cooling of the absorber that serves as negative electrothermal feedback for incoming signal. This feedback is analogous to TES (transition-edge sensor) but additional dc heating is replaced by deep electron cooling to minimum temperature. It could mean a principle breakthrough in realization of supersensitive detectors. Noise properties are considerably improved by decreasing the electron temperature. The loop gain of electrothermal feedback could exceed 1000. The response time is reduced by electrothermal feedback to 10ns in comparison with the intrinsic e-ph time constant of 10ms. The CEB gives opportunity to increase dynamic range by removing all incoming power from supersensitive absorber to the next stage of readout system (SQUID) with higher dynamic range. Saturation problems are not so severe for CEB as for TES: after exceeding the cooling power there is only slight deviation from linear dependence for voltage response. The full saturation comes at the level of 100pW when temperature of absorber achieves Tc of Al. Ultimate performance of the CEB is determined by shot noise of the signal readout. For relatively low background load P0 =10fW and quantization level Te= 50mK, the limit NEP is equal to 10-19W/Hz1/2. The estimations show that it is realistic to achieve ultimate NEP at 100 mK with SQUID readout system and NEP=10-18W/Hz1/2 at 300mK for background load of 10fW. Applicability of the CEB to post-Herschel missions looks very promising.

Kuzmin, Leonid

2004-10-01

371

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

NASA Astrophysics Data System (ADS)

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

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

2001-06-01

372

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

373

Absorbed dose from traversing spherically symmetric, Gaussian radioactive clouds  

Microsoft Academic Search

If a large radioactive cloud is produced, sampling may require that an airplane traverse the cloud. A method to predict the absorbed dose to the aircrew from penetrating the radioactive cloud is needed. Dose rates throughout spherically symmetric Gaussian clouds of various sizes, and the absorbed doses from traversing the clouds, were calculated. Cloud size is a dominant parameter causing

Jay M. Thompson; John W. Poston

1999-01-01

374

Measurement of Tampon Absorbency; Evaluation of Tampon Brands.  

National Technical Information Service (NTIS)

In an earlier report, a protocol for the measurement of tampon absorbency was evaluated. The Syngyna Test, slightly modified for this study, was used to measure the tampon absorbency of all brands of tampons which are currently marketed. This report prese...

D. E. Marlowe

1981-01-01

375

State-Switched Absorber/Damper for Structural Control.  

National Technical Information Service (NTIS)

This project investigated a novel variation on the concept of a tuned vibration absorber or damper: the State-Switched Absorber (SSA). The SSA is capable of altering its stiffness state nearly instantaneously. The change in stiffness causes a change in th...

K. A. Cunefare

2002-01-01

376

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

377

Science on a Roll. Part One: Absorbing Inquiry.  

ERIC Educational Resources Information Center

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

Brendzel, Sharon

2002-01-01

378

A determination of the electron distribution function near absorbing surfaces  

Microsoft Academic Search

A precise description of the electron distribution function near absorbing surfaces has been obtained based on the solution of the inhomogeneous electron Boltzmann equation. The absorbing surface creates a large gradient of the electron distribution function that consequently leads to an axial variation of the electron density and other electron transport parameters. The axial variation of the electron distribution function

George Marinov Petrov; Tzvetelina Petrova

2000-01-01

379

Theory of mode locking with a slow saturable absorber  

Microsoft Academic Search

A closed-form solution is presented for the pulses of a homogeneously broadened laser mode locked by a saturable absorber of relaxation time much longer than the pulsewidth. With suitable approximations, the pulse shape is a secant hyperbolic. The system is described in terms of the linewidth omegaCof the system, the saturation energies of the saturable absorber and the laser medium,

H. Haus

1975-01-01

380

Estimating PAR absorbed by vegetation from bidirectional reflectance measurements  

Microsoft Academic Search

Satellite remote sensing allows estimation, at a global scale, of the photosynthetically active radiation absorbed (APAR) by the vegetation. Current estimates are based on retrieving the fraction (fAPAR) of PAR absorbed by the canopy from spectral vegetation indices (SVI) derived from combinations of spectral reflectance measurements. We show that currently used SVI are strongly affected by the soil reflectance as

Jean-Louis Roujean; François-Marie Breon

1995-01-01

381

Reusable oil absorbent bilge and fuel tank opening pads  

Microsoft Academic Search

For removing oil from the bilge area and fuel tank filler area of a boat, an oil absorbent pad is constructed with an outer wide mesh structural envelope confining and reinforcing an inner containment envelope of woven synthetic crepe material that will absorb oil with a wicking action while repelling water and which will contain therein granular open pore synthetic

Pedone

1977-01-01

382

CFRP-based broad-band Radar Absorbing Materials  

Microsoft Academic Search

Strong interest in radar absorbing materials (RAMs) took place with years due to their extensive sectors of application. RAMs are coatings whose electric and magnetic properties allow the absorption of microwave energy over certain frequencies. In particular, RAMs are very effective means of Radar Cross Section (RCS) reduction in the context of stealth technology. RCS reduction requires absorbers with broad-band

C. Mitrano; A. Balzano; M. Bertacca; M. Flaccavento; R. Mancinelli

2008-01-01

383

Computational method for radar absorbing composite lattice grids  

Microsoft Academic Search

Composite lattice grids reinforced by glass fibers (GFRC) and carbon fibers (CFRC) filled with spongy materials can be designed as lightweight radar absorbing structures (RAS). In the present paper, a computational approach based on periodic moment method (PMM) has been developed to calculate reflection coefficients of radar absorbing composite lattice grids. Total reflection backing (TRB) is considered directly in our

Mingji Chen; Yongmao Pei; Daining Fang

2009-01-01

384

Hybrid multilayer structures for use as microwave absorbing material  

Microsoft Academic Search

The aim of this study is the in situ processing of flexible multilayer radar absorbing structures materials based on polymeric substrates impregnated with polyaniline conducting polymer. There is a growing interest in the development of low density flexible absorber material for applications that require the reduction of the reflectivity of targets with complex shapes and improvement of the ease of

Luiza de C. Folgueras; Mirabel C. Rezende

2007-01-01

385

Application of Impedance Loading to Geometric Transition Radar Absorbent Material  

Microsoft Academic Search

This paper describes a novel, lightweight technique for significantly improving the low-frequency reflectivity performance of conventional geometric transition radar absorbent materials as used typically in anechoic chamber facilities for electromagnetic compatibility testing. The improvement is achieved by the inclusion of impedance-loading elements within the base region of the absorber, and these are implemented in the form of one or more

Kenneth Lee Ford; Barry Chambers

2007-01-01

386

Physically absorbable reagents-collectors in elementary flotation  

SciTech Connect

Based on the reviewed researches held at the Institute of Mining, Siberian Branch, Russian Academy of Sciences, the effect of physically absorbable reagents-collectors on formation of a flotation complex and its stability in turbulent pulp flows in flotation machines of basic types is considered. The basic requirements for physically absorbable reagents-collectors at different flotation stages are established.

S.A. Kondrat'ev; I.G. Bochkarev [Russian Academy of Sciences, Novosibirsk (Russian Federation). Institute of Mining

2007-09-15

387

Microwave Absorbing Property of Stacked Polypyrrole-Coated Nonwoven Textiles  

NASA Astrophysics Data System (ADS)

A new microwave absorber was formed using stacked polypryrrole nanoparticle-coated nonwoven textiles with surface resistivities from 8.5 × 107 to 3.0 ?\\cdotcm. This microwave absorber showed typical frequency dispersion in both \\varepsilonr' and \\varepsilonr'' in a wide frequency range (1 to 75 GHz). A large reflection loss \\dot?21 with a wide bandwidth was achieved with \\varepsilonr'' dispersion characteristics.

Yamamoto, Takashi; Egami, Yoshihiro; Nishida, Ken; Suzuki, Kunio; Inoue, Hiroshi

2011-09-01

388

Moving localized structures in quadratic media with a saturable absorber  

Microsoft Academic Search

Spatial moving pulses are found in an optical resonator with a quadratic medium coupled to an intra-cavity saturable absorber. In the context of frequency degenerate optical parametric oscillators, the saturable absorber is shown to be able to generate large amplitude asymmetric pulses in the transverse section of the signal beam. They arise in a regime where the lasing solution undergoes

A. Barsella; C. Lepers; M. Taki; M. Tlidi

2004-01-01

389

Design Method for Dynamic Vibration Absorbers Considering Excitation Frequency Range  

Microsoft Academic Search

A new optimum design method for dynamic vibration absorbers is proposed for cases when the dynamic characteristics of the primary system vary by a considerable amount and the excitation frequency fluctuates in a small range. When the excitation frequency is constant, it is well known that an undamped dynamic vibration absorber is very effective for attenuating the vibration amplitude of

Yoshio Inoue; Kyoko Shibata

2010-01-01

390

Minimax design of vibration absorbers for linear damped systems  

Microsoft Academic Search

This paper addresses the issue of design of a passive vibration absorber in the presence of uncertainties in the forcing frequency. A minimax problem is formulated to determine the parameters of a vibration absorber which minimize the maximum motion of the primary mass over the domain of the forcing frequency. The limiting solutions corresponding to the forcing frequency being unrestricted

Brandon Brown; Tarunraj Singh

2011-01-01

391

Performance of solar systems employing collectors with colored absorber  

Microsoft Academic Search

Flat plate solar collectors are of black appearance because of the color of the absorber, which is employed to maximize the absorption of solar spectrum. Generally, to avoid the monotony of the black color we can use collectors with absorbers of blue, red–brown, green or other color. These collectors are of lower thermal efficiency than that of the usual black

S. Kalogirou; Y. Tripanagnostopoulos; M. Souliotis

2005-01-01

392

Shock load mitigation using magnetorheological energy absorber with bifold valves  

Microsoft Academic Search

Magnetorheological energy absorbers (MREAs) have been identified as a candidate for tunable impact energy absorber applications, meaning those in which a high shock load is applied during a short time period. In this study, we focused on the theoretical analysis, design and laboratory implementation of a compact high force MREA for shock and impact loads. This study included the design

Min Mao; Wei Hu; Norman M. Wereley; Alan L. Browne; John C. Ulicny

2007-01-01

393

Noise properties of coherent perfect absorbers and critically coupled resonators  

NASA Astrophysics Data System (ADS)

The performance of a coherent perfect absorber (time-reversed laser) is limited by quantum and thermal noise. At zero temperature, the quantum shot noise dominates the signal for frequencies close to the resonance frequency and both vanish exactly at the resonance frequency. We compute the sensitivity of the absorbing cavity as a background-free detector, limited by finite signal or detector bandwidth.

Chong, Y. D.; Cao, Hui; Stone, A. D.

2013-01-01

394

Plasma Walls Beyond the Perfect Absorber Approximation for Electrons  

Microsoft Academic Search

Plasma walls accumulate electrons more efficiently than ions, leading to wall potentials which are negative with respect to the plasma potential. Theoretically, walls are usually treated as perfect absorber for electrons and ions, implying perfect sticking of the particles to the wall and infinitely long desorption times for particles stuck to the wall. For electrons, we question the perfect absorber

Franz X. Bronold; Rafael L. Heinisch; Johannes Marbach; Holger Fehske

2011-01-01

395

Co and Cd Absorber Rod Experiments in ZED-2.  

National Technical Information Service (NTIS)

Experiments have been performed in the ZED-2 critical faclity to evaluate reactivity worths of NRU cobalt and cadmium absorber rods. The object of the measurements was to provide data useful in validating NRU reactor physics codes. Using a Cd or Co absorb...

G. M. Arbique

1981-01-01

396

Voltage tuning of plasmonic absorbers by indium tin oxide  

NASA Astrophysics Data System (ADS)

We experimentally demonstrate electrical tuning of plasmonic mid-infrared absorber resonances at 4 ?m wavelength. The perfect infrared absorption is realized by an array of gold nanostrip antennas separated from a back reflector by a thin dielectric layer. An indium tin oxide active layer strongly coupled to the optical near field of the plasmonic absorber allows for spectral tunability.

Yi, Fei; Shim, Euijae; Zhu, Alexander Y.; Zhu, Hai; Reed, Jason C.; Cubukcu, Ertugrul

2013-06-01

397

Thermogravimetric and calorimetric studies of water absorbed in polyaniline  

Microsoft Academic Search

Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) were used to study the behavior of residual water absorbed by an emeraldine base and a salt of chemically synthesized polyaniline (PANI—EB, PANI-ES). The matrix of PANI is shown to contain water molecules participating in both reversible and irreversible absorption. In its turn, the reversibly absorbed water consists of two components. The

E. S. Matveeva; R. Diaz Calleja; V. P. Parkhutik

1995-01-01

398

Science on a Roll. Part One: Absorbing Inquiry.  

ERIC Educational Resources Information Center

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

Brendzel, Sharon

2002-01-01

399

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

400

A tunable electromagnetic vibration absorber: Characterization and application  

NASA Astrophysics Data System (ADS)

The paper presents a newly designed electromagnetic vibration absorber (EMVA), whose stiffness is on-line tunable. The EMVA is capable of suppressing vibration of the primary system excited by a harmonic force with a variable frequency. The EMVA consists of a clamped clamped aluminum beam and a permanent magnet that is embedded in the center of the beam and placed between two poles of a C-shaped electromagnet. By varying the current of the electromagnet, stiffness of the EMVA can be adjusted instantaneously such that the absorber frequency can be tuned. A detailed characterization of the EMVA is presented. The effective stiffness of the absorber is determined numerically and validated experimentally. To test its effectiveness in vibration suppression, the EMVA is used to track two types of the exciting frequency variations: multi-step and linear. The response of the absorber mass is used to tune the EMVA to ensure that the absorber frequency equals the exciting frequency.

Liu, Jie; Liu, Kefu

2006-08-01

401

Experimental results on indoor electromagnetic wave absorber using magnetic wood  

NASA Astrophysics Data System (ADS)

The purpose of this paper is to propose a new type of indoor electromagnetic wave absorber using magnetic wood. This magnetic wood has good electromagnetic wave absorbing characteristics, a low specific gravity, a wood texture and other wood characteristics and can be easily processed. Electromagnetic wave absorbing characteristics were measured for four types of magnetic wood. The sandwich-type magnetic wood demonstrated the best wave absorbing characteristics among the four types of magnetic wood that were studied. The experimental results showed that the proposed indoor electromagnetic wave absorber can be used to suppress the transmission and reception of cellular phone and Personal Handy Phone System (PHS) signals and can be used as a cross protection for indoor wireless Local Area Networks (LAN). This wood can be processed for use in furniture, building materials, and other applications.

Oka, Hideo; Narita, Koichi; Osada, Hiroshi; Seki, Kyoushirou

2002-05-01

402

Improvement on the wave absorbing property of a lossy frequency selective surface absorber using a magnetic substrate  

NASA Astrophysics Data System (ADS)

An equivalent-circuit model is used to analyse the improvement of the wave absorbing performance of the lossy frequency selective surface (FSS) absorber by using a magnetic substrate, showing that it is possible to widen the wave absorbing bandwidth. Three pieces of magnetic substrates are prepared. According to the complex permittivity and permeability, the reflectivity of the corresponding absorber is calculated by the finite difference time-domain (FDTD) method, and the bandwidth of the reflectivity below -10 dB is optimized by genetic algorithm. The calculated results indicate that the wave absorbing performance is significantly improved by increasing the complex permeability of the substrate; the reflectivity bandwidth below -10 dB of the single layer FSS absorber can reach 3.6-18 GHz with a thickness of 5 mm, which is wider than that with a dielectric substrate. The density of the FSS absorber is only 0.92 g/cm3. Additionally, the absorption band can be further widened by inserting a second lossy FSS. Finally, a double layer lossy FSS absorber with a magnetic substrate is fabricated based on the design result. The experimental result is consistent with the design one.

Sun, Liang-Kui; Cheng, Hai-Feng; Zhou, Yong-Jiang; Wang, Jun

2012-05-01

403

Probing Cold Dense Nuclear Matter  

SciTech Connect

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

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

2008-06-01

404

Axinos as Cold Dark Matter  

SciTech Connect

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

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

2006-11-28

405

Modeling Hot and Cold Planets  

NSDL National Science Digital Library

These are the student pages for a three part lesson plan in which students investigate a physical model representing a cold and a hot planet. In the second part, the students interact with a computer model that simulates extreme conditions on some planets, and in the third part they will utilize a data source from the internet to determine the average temperature of the earth and specify the characteristics of a sampling necessary to achieve an accurate average. The lesson plan includes an overview, learning objectives, a list of materials, procedure, data analysis, and worksheets. Teachers' notes are also included.

406

Principles of quantitative absorbance measurements in anisotropic crystals  

NASA Astrophysics Data System (ADS)

The accurate measurement of absorbance ( A=-log T; T=I/I 0) in anisotropic materials like crystals is highly important for the determination of the concentration and orientation of the oscillator (absorber) under investigation. The absorbance in isotropic material is linearly dependent on the concentration of the absorber and on the thickness of the sample ( A=?·c·t). Measurement of absorbance in anisotropic media is more complicated, but it can be obtained from polarized spectra (i) on three random, but orthogonal sections of a crystal, or (ii) preferably on two orthogonal sections oriented parallel to each of two axes of the indicatrix ellipsoid. To compare among different crystal classes (including cubic symmetry) it is useful to convert measured absorbance values to one common basis (the total absorbance A tot), wherein all absorbers are corrected as if they were aligned parallel to the E-vector of the incident light. The total absorption coefficient ( a tot= A tot/ t) is calculated by 269_2004_Article_BF00199497_TeX2GIFE1.gif left( {text{i}} right)a_{{text{tot}}} = sumlimits_{i = 1}^3 {(a_{max ,i} + a_{min ,i} )} /2, {text{or}} {text{by}} {text{(ii) }}a_{{text{tot}}} = a_x + a_y + a_z . Only in special circumstances will unpolarized measurements of absorbance provide data useful for quantitative studies of anisotropic material. The orientation of the absorber with respect to the axes of the indicatrix ellipsoid is calculated according to A x/ A tot=cos2 ( x < absorber), and analogously for A yand A z. In this way, correct angles are obtained for all cases of symmetry. The extinction ratio of the polarizer ( Pe=I crossed/ I parallel) has considerable influence on the measured amplitude of absorption bands, especially in cases of strong anisotropic absorbance. However, if Pe is known, the true absorbance values can be calculated even with polarizers of low extinction ratio, according to A max=-log[( T max,obs-0.5· Pe· T min,obs)/(1-0.5· Pe)], and similar for A min. The theoretical approach is confirmed by measurements on calcite and topaz.

Libowitzky, Eugen; Rossman, George R.

1996-08-01

407

TRPA1 Contributes to Cold Hypersensitivity  

PubMed Central

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

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

2010-01-01

408

Anaerobic Bacteria and Archaea in Cold Ecosystems  

Microsoft Academic Search

Permanently cold environments are very common on Earth. For example, the average temperature in bottom waters of the largest\\u000a fraction of the world oceans is 5°C or less and including terrestrial habitats about 80% of the Earth's biosphere is to be\\u000a found in permanently cold habitats (Russell 1990). In addition to being cold, many of these environments are also oxygen-free,

Kai Finster

409

Cold storage of Phytoseiulus persimilis (Phytoseiidae)  

Microsoft Academic Search

Phytoseiulus persimilis is commerelally mass-reared for use as a biological control agent for spider mites, primarilyTetranychus urticae, and cold storage is a potentially valuable aspect of mass-production. Cold storage ofP. persimilis in empty containers was found to be unsatisfactory, but provision of moisture during cold storage greatly increased survival. Provision of food further increased survival even though the mites were

W. D. Morewood

1992-01-01

410

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, W.G.

1982-02-09

411

Experimental verification of metamaterial based subwavelength microwave absorbers  

NASA Astrophysics Data System (ADS)

We designed, implemented, and experimentally characterized electrically thin microwave absorbers by using the metamaterial concept. The absorbers consist of (i) a metal back plate and an artificial magnetic material layer; (ii) metamaterial back plate and a resistive sheet layer. We investigated absorber performance in terms of absorbance, fractional bandwidth, and electrical thickness, all of which depend on the dimensions of the metamaterial unit cell and the distance between the back plate and metamaterial layer. As a proof of concept, we demonstrated a ?/4.7 thick absorber of type I, with a 99.8% absorption peak along with a 8% fractional bandwidth. We have shown that as the electrical size of the metamaterial unit cell decreases, the absorber electrical thickness can further be reduced. We investigated this concept by using two different magnetic metamaterial inclusions: the split-ring resonator (SRR) and multiple SSR (MSRR). We have also demonstrated experimentally a ?/4.7 and a ?/4.2 thick absorbers of type II, based on SRR and MSRR magnetic metamaterial back plates, respectively. The absorption peak of the SRR layout is 97.4%, while for the MSRR one the absorption peak is 98.4%. The 10 dB bandwidths were 9.9% and 9.6% for the SRR and MSRR cases, respectively.

Alici, Kamil Boratay; Bilotti, Filiberto; Vegni, Lucio; Ozbay, Ekmel

2010-10-01

412

Simulation, fabrication and characterization of THz metamaterial absorbers.  

PubMed

Metamaterials (MM), artificial materials engineered to have properties that may not be found in nature, have been widely explored since the first theoretical(1) and experimental demonstration(2) 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 optical(3), near IR(4), mid IR(5) , THz(6) , mm-wave(7) , microwave(8) and radio(9) bands. Applications include perfect lenses(10), sensors(11), telecommunications(12), invisibility cloaks(13) and filters(14,15). We have recently developed single band(16), dual band(17) and broadband(18) 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 absorbers(19). 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

2012-12-27

413

Primary cold agglutinin disease: a case report.  

PubMed

Chronic cold agglutinin disease is a subgroup of auto-immune haemolytic anaemia. Primary cold agglutinin disease has traditionally been defined by the absence of any underlying or associated disease. It usually affects elderly. The term cold refers to the fact that the auto-antibody involved reacts with red cells poorly or not at all at 37 degrees C, whereas it reacts strongly at lower temperature. Here a case of severe pallor, jaundice and red colour urine in winter season for last 10 years diagnosed as a case of primary cold agglutinin disease is reported.The patient was managed conservatively. PMID:23738411

Das, Susanta Kumar; Ghosh, Amritava; Banerjee, Niloy; Khaskil, Sudarshan; Mukherjee, Sabya Sachi

2012-10-01

414

Sound waves in ultra-cold matter  

NASA Astrophysics Data System (ADS)

We review recent theoretical work on various types of sound waves, which take place in different phases of the ultra-cold matter. These phases can be identified as the steady-state ultracold gas, the Bose Einstein condensates, and the ultra-cold Rydberg plasmas. Sound waves appear as similar but distinct manifestations of low frequency oscillations in the three phases: hybrid sound waves in the non-condensed ultra-cold gas, Bogoliubov oscillations in condensates, and ion acoustic waves in expanding ultra-cold plasmas, are successively described and compared.

Mendonça, J. T.

2012-02-01

415

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

416

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

417

Evaluation of Two Cold Thermoregulatory Models for Prediction of Core Temperature During Exercise in Cold Water.  

National Technical Information Service (NTIS)

COld thermoregulatory model(CTM) have primirily been developed to predict core temperature (t sub core) responses during sednetary immersion. Few studies have examined their efficacy to predict T(sub core) during exercise cold exposure. The purpose of thi...

C. O'Brien I. V. Sils J. W. Castellani P. Tikuisis X. Xu

2007-01-01

418

Solar absorber material stability under high solar flux  

NASA Astrophysics Data System (ADS)

Solar absorbing Black Chrome coatings have been exposed to high temperatures (350-400 C) under high solar fluxes (0.4 to 2.0 MW/sq m) to test for their stability under actual operating conditions. Field tests at the White Sands Solar Furnace have shown higher stability than expected from oven tested samples. Laboratory studies utilizing spectrally selective concentrated solar simulated radiation have indicated that the cause of the higher stability under solar irradiation is photo-stimulated desorption of oxygen bearing species at the absorber surface and resultant reduced oxidation of the absorber.

Ignatiev, A.; Zajac, G.; Smith, G. B.

419

Absorbable, invisible, and flexible plating system for the craniofacial skeleton.  

PubMed

This report demonstrates further experience in the use of the absorbable plating system since our preliminary report in 1996. We found more indications for the application of the absorbable plating system in the craniofacial skeleton in children and in covering cranial bone graft donor sites. The system is unique, the applications are widespread over the horizon, and the only limitations are those of the operating surgeon. The advantage is that in 1 year the system absorbs completely by hydrolysis, giving minimal inflammatory reaction at the site. PMID:10332279

Habal, M B

1997-03-01

420

Microwave absorbing properties of ferrite-based nanocomposites  

NASA Astrophysics Data System (ADS)

A study of the microwave absorbing properties of polymer (epoxy) based nanocomposites is presented. The ferrite nanoparticles employed as filler materials were produced by a co-precipitation method, which was designed for production of large amounts at low cost. The absorbing properties of different kinds of ferrite nanoparticles, soft (manganese) and hard (cobalt) magnetic nanoparticles, are compared. In addition, the impact of high and low densities of the respective ferrite type has been investigated. Our analysis of the microwave absorbing properties is made over a wide frequency band including both MHz and GHz regions, which is of high interest for a number of different applications both military and civilian.

Jänis, A.; Olsson, R. T.; Savage, S. J.; Gedde, U. W.; Klement, U.

2007-04-01

421

Experimental development and theoretical studies of radio-frequency absorbers  

NASA Astrophysics Data System (ADS)

A mathematical model based on the equivalence with a sequence of lossy transmission lines has been developed and applied, by numerical calculus, to the study of radio-frequency absorbers of piramidal shape, made of polyurethane foam impregnated with finely powered carbon black. The model has been used to find the expected performance of absorbers with different electrical conductivities in the microwave range of frequencies. The results agree with the measurements of reflectivity which have been previously obtained, by the arch method, during the phase of experimental development of the absorbers, when the carbon black concentration was progressively changed.

Massa, J. L. L. M.

1991-04-01

422

Infrared perfect absorber based on nanowire metamaterial cavities.  

PubMed

An infrared perfect absorber based on a gold nanowire metamaterial cavities array on a gold ground plane is designed. The metamaterial made of gold nanowires embedded in an alumina host exhibits an effective permittivity with strong anisotropy, which supports cavity resonant modes of both electric dipole and magnetic dipole. The impedance of the cavity modes matches the incident plane wave in free space, leading to nearly perfect light absorption. The incident optical energy is efficiently converted into heat so that the local temperature of the absorber will increase. Results show that the designed absorber is polarization-insensitive and nearly omnidirectional for the incident angle. PMID:23546283

He, Yingran; Deng, Huixu; Jiao, Xiangyang; He, Sailing; Gao, Jie; Yang, Xiaodong

2013-04-01

423

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

424

Genotypic variation for cold tolerance during reproductive development in rice: Screening with cold air and cold water  

Microsoft Academic Search

Rice (Oryza sativa L.) plants are susceptible to low temperature during the young microspore stage, which occurs 10–12 days before heading. Low temperature at this time increases spikelet sterility which can cause massive yield loss. Increasing the cold tolerance of cultivars can reduce yield variability in temperate rice-growing environments. Two experiments were conducted in cold air screenings and two were

T. C. Farrell; K. M. Fox; R. L. Williams; S. Fukai

2006-01-01

425

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

426

Respiratory and Cardiovascular Responses to Cold Stress Following Repeated Cold Water Immersion,  

National Technical Information Service (NTIS)

The effects of cold acclimation (CA) on the cardiorespiratory responses to cold air and water stress tests (CST) were studied in seven males before and after a CA program of daily 90 min cold water (18 C) immersions repeated five times a week for five con...

S. B. Muza A. J. Young M. N. Sawka J. E. Bogart K. B. Pandolf

1987-01-01

427

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

428

[Russian intra vehicular space suit and cold protection].  

PubMed

During space flights, astronauts use equipment allowing protection against many environmental factors. During tests realised in Russia, space suit efficiency was evaluated particularly concerning cold protection capacity in cold water (3 degrees C) and in cold air (-30 degrees C). Obtained results prove that this equipment allows to prevent hypothermia in cold water and ensure thermal comfort in cold air. PMID:11541088

Lejeune, D; Beaumont, M; Marotte, H; Loncle, M

1997-01-01

429

Cold gas accretion in galaxies  

NASA Astrophysics Data System (ADS)

Evidence for the accretion of cold gas in galaxies has been rapidly accumulating in the past years. H I observations of galaxies and their environment have brought to light new facts and phenomena which are evidence of ongoing or recent accretion: (1) A large number of galaxies are accompanied by gas-rich dwarfs or are surrounded by H I cloud complexes, tails and filaments. This suggests ongoing minor mergers and recent arrival of external gas. It may be regarded, therefore, as direct evidence of cold gas accretion in the local universe. It is probably the same kind of phenomenon of material infall as the stellar streams observed in the halos of our galaxy and M 31. (2) Considerable amounts of extra-planar H I have been found in nearby spiral galaxies. While a large fraction of this gas is undoubtedly produced by galactic fountains, it is likely that a part of it is of extragalactic origin. Also the Milky Way has extra-planar gas complexes: the Intermediate- and High-Velocity Clouds (IVCs and HVCs). (3) Spirals are known to have extended and warped outer layers of H I. It is not clear how these have formed, and how and for how long the warps can be sustained. Gas infall has been proposed as the origin. (4) The majority of galactic disks are lopsided in their morphology as well as in their kinematics. Also here recent accretion has been advocated as a possible cause. In our view, accretion takes place both through the arrival and merging of gas-rich satellites and through gas infall from the intergalactic medium (IGM). The new gas could be added to the halo or be deposited in the outer parts of galaxies and form reservoirs for replenishing the inner parts and feeding star formation. The infall may have observable effects on the disk such as bursts of star formation and lopsidedness. We infer a mean “visible” accretion rate of cold gas in galaxies of at least {0.2 M_{odot} year^{-1}} . In order to reach the accretion rates needed to sustain the observed star formation ({? 1 M_{odot} year^{-1}}), additional infall of large amounts of gas from the IGM seems to be required.

Sancisi, Renzo; Fraternali, Filippo; Oosterloo, Tom; van der Hulst, Thijs

2008-06-01

430

Cold exposure increases intestinal paracellular permeability to nutrients in the mouse.  

PubMed

In situations of increased energy demand and food intake, animals can often acclimate within several days. The intestine generally responds to elevated digestive demand by increasing in size. However, there is likely a limit to how quickly the intestine can grow to meet the new demand. We investigated the immediate and longer-term changes to intestinal properties of the mouse when suddenly exposed to 4°C. We hypothesized that paracellular permeability to nutrients would increase as part of an immediate response to elevated absorptive demand. We measured absorption of l-arabinose, intestinal size and gene expression of several tight junction proteins (claudin-2, claudin-4, claudin-15 and ZO-1) at three time points: pre-exposure, and after 1 day and 2 weeks of cold exposure. Cold exposure increased food intake by 62% after 2 weeks but intake was not significantly increased after 1 day. Intestinal wet mass was elevated after 1 day and throughout the experiment. Absorption of arabinose rose by 20% after 1 day in the cold and was 33% higher after 2 weeks. Expression of claudin-2 increased after 1 day of cold exposure, but there were no changes in expression of any claudin genes when normalized to ZO-1 expression. Our results indicate that intestinal mass can respond rapidly to increased energy demand and that increased paracellular permeability is also part of that response. Increased paracellular permeability may be a consequence of enterocyte hyperplasia, resulting in more tight junctions across which molecules can absorb. PMID:23913950

Price, Edwin R; Ruff, Lisa J; Guerra, Alberto; Karasov, William H

2013-08-02

431

Integrated microcalorimeters using Ir TES and Sn mushroom absorbers  

NASA Astrophysics Data System (ADS)

The University of Miami has recently started a program to fabricate fully integrated microcalorimeter arrays using iridium thin films as Transition Edge Sensors (TES) and tin mushroom absorbers. We present our preliminary results in both areas.

Galeazzi, M.; Bogorin, D.; Chen, C.

2006-04-01

432

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

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

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

433

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

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

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

434

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

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

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

435

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

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

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

436

Composite infrared bolometers with Si3N4 micromesh absorbers.  

PubMed

We report the design and performance of 300-mK composite bolometers that use micromesh absorbers and support structures patterned from thin films of low-stress silicon nitride. The small geometrical filling factor of the micromesh absorber provides 20x reduction in heat capacity and cosmic ray cross section relative to a solid absorber with no loss in IR-absorption efficiency. The support structure is mechanically robust and has a thermal conductance, G < 2 x 10(-11) W/K, which is four times smaller than previously achieved at 300 mK. The temperature rise of the bolometer is measured with a neutron transmutation doped germanium thermistor attached to the absorbing mesh. The dispersion in electrical and thermal parameters of a sample of 12 bolometers optimized for the Sunyaev-Zel'dovich Infrared Experiment is +/-7% in R (T), +/-5% in optical efficiency, and +/-4% in G. PMID:18250736

Mauskopf, P D; Bock, J J; Del Castillo, H; Holzapfel, W L; Lange, A E

1997-02-01

437

Liquid absorbent solutions for separating nitrogen from natural gas  

DOEpatents

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

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

2000-01-01

438

Microwave-absorbing properties of Co-filled carbon nanotubes  

SciTech Connect

Co-filled carbon nanotubes composites were synthesized via using a simple and efficient wet chemistry solution method. The samples were characterized by transmission electron microscopy. Microwave-absorbing properties were investigated by measuring complex permittivity and complex permeability of the absorber in a frequency range of 2-18 GHz. The reflection loss (R.L.), matching frequency (f{sub m}) and matching thickness (d{sub m}) were calculated using the theory of the absorbing wall. The electromagnetic properties and microwave-absorbing characteristics effects of the modified carbon nanotubes by the encapsulation of metal Co were investigated. A matching thickness is found corresponding to a matching frequency. The maximum reflection loss is about -39.32 dB and the bandwidth corresponding to the reflection loss below -10 dB is 3.47 GHz. With increasing thickness, the maximum reflection loss shifts to lower frequency.

Lin Haiyan [School of Science, Beijing Jiaotong University, Beijing 100044 (China); Zhu Hong [School of Science, Beijing Jiaotong University, Beijing 100044 (China)], E-mail: zhuho128@263.net; Guo Hongfan; Yu Liufang [School of Science, Beijing Jiaotong University, Beijing 100044 (China)

2008-10-02

439

Theoretical and experimental investigation of hybrid broadband terahertz metamaterial absorber  

NASA Astrophysics Data System (ADS)

Among electromagnetic spectrum, terahertz region has been utilized less due to the lack of appropriate devices that works well in these frequencies But recently growing interest has been focused to design devices with functionality in terahertz region because of potential terahertz applications. We present a novel structure that broadens bandwidth of terahertz metamaterial absorber. Our structure takes a benefit of multiband absorber by making the bands close enough to each other but in a multilayer pattern. The absorber has composed of two concentric copper rings in two different layers followed by polyimide and a metal back layer. Simulation shows 100 GHz bandwidth which is double of that of a single layer single ring absorber.

Hokmabadi, Mohammad P.; Wilbert, David S.; Kung, Patrick; Kim, Seongsin M.

2013-02-01

440

Horizontal Radiative Fluxes in Clouds at Absorbing Wavelengths.  

National Technical Information Service (NTIS)

We discuss the effect of horizontal fluxes on the accuracy of a conventional plane-parallel radiative transfer calculation for a single pixel, known as the Independent Pixel Approximation (IPA) at absorbing wavelengths. Vertically integrated horizontal fl...

A. Marshak L. Oreopoulos A. B. Davis W. J. Wiscombe

1998-01-01

441

Diagnostic beam absorber in Mu2e beam line  

SciTech Connect

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

Rakhno, Igor; /Fermilab

2011-03-01

442

21 CFR 878.4490 - Absorbable hemostatic agent and dressing.  

Code of Federal Regulations, 2013 CFR

...FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Surgical Devices § 878.4490 Absorbable hemostatic agent and dressing. (a)...

2013-04-01

443

Equilibrium-Vapor Cell for Quantitative Infrared Absorbance Measurements.  

National Technical Information Service (NTIS)

Infrared (IR) absorbance measurements, through a gas flow cell, are made with the closed-loop circulation of vapor-air mixtures that are generated by temperature equilibrated aqueous solutions. Accurate vapor pressures of organic solutes are established w...

P. E. Field R. J. Combs R. B. Knapp

1995-01-01

444

The MuCool/MICE LH2 Absorber Program  

NASA Astrophysics Data System (ADS)

Hydrogen absorber R&D for the MuCool Collaboration is actively pushing ahead on two parallel and complementary fronts. The continuing LH2 engineering and technical developments by the MuCool group, conducted by ICAR institutions (NIU, IIT and UIUC), the University of Mississippi and Oxford University in cooperation with Fermilab, are summarized here, including plans for the first tests of an absorber prototype from Osaka University and KEK cooled by internal convection at the newly constructed FNAL MuCool Test Area (MTA). Designs for the high-power test of another absorber prototype (employing external heat exchange) are complete and the system will be installed by summer 2004. A convection-cooled absorber design is being developed for the approved MICE cooling demonstration at Rutherford Appleton Laboratory.

Cummings, Mary Anne

2004-10-01

445

The Mucool/mice LH2 Absorber Program  

NASA Astrophysics Data System (ADS)

The continuing LH2 R & D by the MuCool group, conducted by Illinois Consortium for Accelerator Research (ICAR) institutions (NIU, IIT and UIUC), the University of Mississippi, Oxford University and Fermilab, are summarized here, including results for the first hydrogen tests of an absorber prototype from Osaka University and KEK cooled by internal convection at the newly constructed FNAL MuCool Test Area (MTA). The program includes designs for the high-powered test of an absorber prototype (external heat exchange) at the MTA which are nearing completion to be installed by fall 2005, an alternative absorber design (internal heat exchange) being finalized for the approved cooling experiment (MICE) at Rutherford-Appleton Laboratory, and a novel idea for gaseous hydrogen absorbers being developed at Fermilab for a high powered test at the MTA in 2006.

Cummings, M. A. C.

446

DEVELOPMENT OF SOYBEAN OIL-BASED ENERGY ABSORBING MATERIALS  

Technology Transfer Automated Retrieval System (TEKTRAN)

The energy absorbing materials were prepared from epoxidized soybean oil with three different curing agents: Jeffamine EDR-148 (EDR-148), diethylenetriamine (DETA) and triethylenetetramine (TETA). Resulting polymers exhibited tensile stress-strain behavior similar to rubbery materials with good da...

447

Wave Absorber with Fine Weatherability for Improving ETC Environment  

NASA Astrophysics Data System (ADS)

Wave absorber of rubber sheet containing natural rubber and EPDM is designed, fabricated and measured for improving ETC environment. As a result, proposed absorption material has fine weatherability and wave absorption satisfied with ETC standard can be realized theoretically before and after the weatherability test if the thickness of absorber is fabricated at the ranging from 2.26mm to 2.52mm. Moreover, absorber sheet sample based on theoretical values is fabricated and are measured. As a result, 20dB or more is also confirmed at the incident angle ranging from 5 to 55 degrees experimentally. Therefore, the wave absorber with fine weatherability being satisfied with ETC standard can be realized.

Miura, Yu; Matsumoto, Kouta; Okada, Osamu; Hashimoto, Osamu

448

The cold-fog test  

SciTech Connect

The electrical performance of outdoor insulation degrades severely during combinations of factors that include surface contamination (C), ice (I), fog (F) and an ambient temperature that rises through 0 C (T{sub 0{degree}}). Failures at operating voltage on 115-kV, 230-kV and 500-kV systems occur with increasing probability under these conditions. A new CFT{sub 0{degree}} or cold-fog test method has been developed to reproduce the flashovers at all three voltage levels. Three options are identified for improving CFT{sub 0{degree}} performance: use of semi-conductive glazes, substitution of silicone for porcelain and use of silicone coatings on existing porcelain insulators.

Chisholm, W.A.; Ringler, K.G.; Erven, C.C. [Ontario Hydro Technologies, Toronto, Ontario (Canada)] [and others

1996-10-01

449

Compensating for cold war cancers.  

PubMed

Although the Cold War has ended, thousands of workers involved in nuclear weapons production are still living with the adverse health effects of working with radioactive materials, beryllium, and silica. After a series of court battles, the U.S. government passed the Energy Employees Occupational Illness Act in October 2000 to financially assist workers whose health has been compromised by these occupational exposures. Now work is underway to set out guidelines for determining which workers will be compensated. The National Institute for Occupational Safety and Health has been assigned the task of developing a model that can scientifically make these determinations, a heavy task considering the controversies that lie in estimating low-level radiation risks and the inadequate worker exposure records kept at many of the plants. PMID:12117658

Parascandola, Mark J

2002-07-01

450

Cold warriors target arms control  

SciTech Connect

While disagreements over the conflict in Bosnia have strained US relations with Western Europe and Russia, these divisions will pale in comparison to the tensions that will arise if recent congressional arms control decisions become law. If the Republicans who dominate Congress are successful, a series of arms control agreements painstakingly negotiated by Republican and Democratic presidents could be consigned to the ash heap. This list includes the Start I and Start II nuclear reduction agreements, the 1972 Anti-Ballistic Missile (ABM) Treaty and the ongoing negotiations to achieve a comprehensive test ban (CTB) by 1996. US leadership in the post-Cold War era will undermined as the international community, already skeptical about this country`s direction, will question the ability of the executive branch to surmount isolantionist impulses.

Isaacs, J.

1995-09-01

451

Gaseous saturable absorbers for the Helios CO2 laser systems  

Microsoft Academic Search

Saturable absorbers are widely used to suppress parasitic oscillations in large-aperture, high-power CO2 fusion-laser systems. This paper reports experimental results on SF6-based gaseous saturable absorbers used for parasitic suppression in the eight-beam, 10 kJ Helios fusion-laser system. The gas mix effectively quenches self-lasing in the 9 and 10 microns branches of the CO2 laser spectrum while simultaneously allowing high transmission

R. F. Haglund Jr.; A. V. Nowak; S. J. Czuchlewski

1981-01-01

452

Characteristics of new-type energy absorber for vehicle collision  

Microsoft Academic Search

A new type energy absorber was introduced, which is composed of thousands of thin ring plates with different diameters. Because\\u000a it can switch the impact to thousands of shearing actions among thin ring plates inside the absorber, the impact energy is\\u000a decentralized and dissipated gradually, the impact acting time is extended and the peak of acceleration is reduced obviously.\\u000a Numerical

Qing-xin Xu; Rong-ying Shen; Hai-ting Zhou

2008-01-01

453

Development of absorber coupled TES polarimeter at millimeter wavelengths.  

SciTech Connect

We report an absorber coupled TES bolometric polarimeter, consisting of an absorptive metal grid and a Mo/Au bi-layer TES on a suspended silicon nitride membrane disk. The electromagnetic design of the polarization sensitive absorbers, the heat transport modeling of the detector, the thermal response of the TES, and the micro-fabrication processes are presented. We also report the results of laboratory tests of a single pixel prototype detector, and compare with theoretical expectations.

Wang, G.; Yefremenko, V.; Novosad, V.; Bleem, L.; Chang, C.; McMahon, J.; Datesman, A.; Pearson, J.; Divan, R.; Downes, T.; Crites, A. T.; Meyer, S. S.; Carlstrom, J. E.; Univ. of Chicago

2009-06-01

454

Three intervening galaxy absorbers towards GRB 060418: faint and dusty?  

Microsoft Academic Search

We present an analysis of three strong, intervening Mg II absorption systems (zabs = 0.603, 0.656, 1.107) towards the optical afterglow of gamma-ray burst (GRB) 060418. From high-resolution Ultraviolet and Visual Echelle Spectrograph (UVES) spectra we measure metal column densities and find that the highest redshift absorber exhibits a large amount of dust depletion compared with damped Lyman absorbers (DLAs)

Sara L. Ellison; Paul Vreeswijk; Cédric Ledoux; Jon P. Willis; Andreas Jaunsen; Ralph A. M. J. Wijers; Alain Smette; Johan P. U. Fynbo; Palle Møller; Jens Hjorth; Andreas Kaufer

2006-01-01

455

Stretched-pulse fiber lasers based on semiconductor saturable absorbers  

Microsoft Academic Search

Stretched-pulse mode-locked erbium-doped fiber lasers based on monolithically grown InGaAsP\\/InP semiconductor saturable absorber mirrors are described. The saturable absorbers are used to initiate the mode locking, to stabilize the pulse train and to control the cavity dispersion. We obtained reliable operation at the fundamental repetition rate with 1.3 nJ of pulse energy, limited by the maximum available pump power of 175 mW.

M. Guina; N. Xiang; O. G. Okhotnikov

2002-01-01

456

Monocryl® suture, a new ultra-pliable absorbable monofilament suture  

Microsoft Academic Search

Synthetic absorbable sutures are available as braided constructions or as monofilaments. Braided absorbable sutures are made either from 90:10 poly(glycolide-co-l(?)-lactide), sold by Ethicon, Inc. under the trade name Vicryl®, or from polyglycolide, as sold, for instance, by Davis and Geck under the trade name Dexon®. There are, however, some concerns with braided sutures that relate to tissue drag and the

Rao S. Bezwada; Dennis D. Jamiolkowski; In-Young Lee; Vishvaroop Agarwal; Joseph Persivale; Susan Trenka-Benthin; Modesto Erneta; Jogendra Suryadevara; Alan Yang; Sylvia Liu

1995-01-01

457

Star Library: Which Paper Towel is More Absorbent?  

NSDL National Science Digital Library

This group activity focuses on conducting an experiment to determine which of two brands of paper towels are more absorbent by measuring the amount of water absorbed. A two-sample t-test can be used to analyze the data, or simple graphics and descriptive statistics can be used as an exploratory analysis. Students are asked to think about design issues, and to write a short report stating their results and conclusions, along with an evaluation of the experimental design.

Malone, Christopher; Boyer, John E.; Rumsey, Deborah J.; Bilder, Christopher R.

2009-02-11

458

Fundamental principles of absorbed dose determination in radiation technology  

Microsoft Academic Search

The use of ionizing radiation in radiation technology is characterized by a number of features associated with the high values of the absorbed dose (i04-i09 rad) and the absorbed dose intensity (10-107 rad\\/sec) as well as the extensive assortment of objects of exposure of different chemical composition. The main radiation sources used in radiation technology are powerful gamma apparatus with

V. A. Berlyand; Yu. I. Bregadze; V. V. Generalova; M. N. Gurskii; B. M. Isaev

1979-01-01

459

Multi-objective optimization design of radar absorbing sandwich structure  

Microsoft Academic Search

By introducing a dimensionless parameter to couple the two objectives, weight and radar absorbing performance, into a single\\u000a objective function, a multi-objective optimization procedure for the radar absorbing sandwich structure (RASS) with a cellular\\u000a core is proposed. The optimization models considered are one-side clamped sandwich panels with four kinds of cores subject\\u000a to uniformly distributed loads. The average specular reflectivity

Ming-ji Chen; Yong-mao Pei; Dai-ning Fang

2010-01-01

460

Exergy analysis of absorber using water\\/lithium bromide solution  

Microsoft Academic Search

It is necessary to understand the heat and mass transfer processes and determine the variation of the exergy destruction in\\u000a the absorber for improving the performance. In this study, the exergy analysis of a coil absorber using water\\/lithium bromide\\u000a solution pair is carried out. By using the developed simulation, the effects of variation of parameters affecting the performance\\u000a of the

O. Kaynakli

2008-01-01

461

Determining factors for high performance silicone rubber microwave absorbing materials  

NASA Astrophysics Data System (ADS)

Silicone rubber microwave absorbing materials (RMAMs) based on ferrite as the major absorbent were prepared by the mechanical blending method. The determining factors for the complex permittivity, complex permeability, and reflectivity of RMAM were thoroughly investigated with various samples including different crystal structures of Ba-ferrite (M-type, W-type, and Y-type), the ferrite with doped elements (Ba, Sr), the materials' thickness, the combination ratio of ferrite and carbonyl iron. The effects of surface modification and loading amount of ferrite on the mechanical properties, processing performance, and absorbing property of RMAM were also assessed. The results show that W-type Ba-ferrite based RMAM exhibits better absorbing property at high frequencies (8-18 GHz) than the other two barium ferrites (M-type and Y-type) based ones, and the absorbing property of RMAM based on Sr-ferrite is best. As the thickness of RMAM and the amount of absorbents increase, the absorption peak moves toward low frequency, the absorption frequency bandwidth is narrowed, and the reflectivity first decreases and later increases. The optimum thickness is 1.5-1.7 mm, and the amount of ferrite is 450 parts per hundreds of rubber (phr). Surface modification of the absorbent with silane coupling agent could improve the mechanical properties and processing performance of RMAM. It is concluded that there will be a synergistic effect when carbonyl iron (CI) is used in combination with Sr-ferrite (Sr-W) in an appropriate proportion. When the total volume fraction of absorbents is 51%, the optimum ratio of Cl to Sr-W is 17:34, the absorption frequency bandwidth (<-10 dB) is about 8 GHz, and the absorption area is -99 dB.

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

2011-06-01

462

Plasma walls beyond the perfect absorber approximation for electrons  

Microsoft Academic Search

Plasma walls accumulate electrons more efficiently than ions leading to wall\\u000apotentials which are negative with respect to the plasma potential.\\u000aTheoretically, walls are usually treated as perfect absorber for electrons and\\u000aions implying perfect sticking of the particles to the wall and infinitely long\\u000adesorption times for particles stuck to the wall. For electrons we question the\\u000aperfect absorber

Franz X. Bronold; Rafael L. Heinisch; Johannes Marbach; Holger Fehske

2010-01-01

463

Perfect absorbers on curved surfaces and their potential applications.  

PubMed

Recently perfect metamaterial absorbers triggered some fascination since they permit the observation of an extreme interaction of light with a nanostructured thin film. For the first time we evaluate here the functionality of such perfect absorbers if they are applied on curved surfaces. We probe their optical response and discuss potential novel applications. Examples are the complete suppression of back-scattered light from the covered objects, rendering it cloaked in reflection, and their action as optical black holes. PMID:23038388

Alaee, Rasoul; Menzel, Christoph; Rockstuhl, Carsten; Lederer, Falk

2012-07-30

464

A novel composite sound absorber with recycled rubber particles  

NASA Astrophysics Data System (ADS)

A new kind of composite sound absorber has been fabricated, using recycled rubber particles with good attenuation property as sound energy attenuation layer, low characteristic impedance materials such as polymer porous foam or perforated panel as matching layer. Its’ attractive characteristics include: low-cost, broad-band sound absorption, thin in thickness and relatively simple processing. An acoustic transmission analytical model is developed and successfully applied to evaluate the sound absorption of the composite absorber.

Hong, Zhou; Bo, Li; Guangsu, Huang; Jia, He

2007-07-01

465

China's security agenda after the cold war  

Microsoft Academic Search

The end of the cold war has changed China's basic perception of world politics and its conception of national security. In the cold war era, Chinese leaders tended to view national security from the perspective of global balance of power and China's strategic relations with the two superpowers. It was in Beijing's security interests to maintain a comfortable position in

Weixing Hu

1995-01-01

466

A Cool Channel in Cold Transduction  

NSDL National Science Digital Library

Transient receptor potential melastatin 8 (TRPM8), a calcium-permeable cation channel activated by cold, cooling compounds and voltage, is the main molecular entity responsible for detection of cold temperatures in the somatosensory system. Here, we review the biophysical properties, physiological role, and near-membrane trafficking of this exciting polymodal ion channel.

PhD Ramon Latorre (Universidad de Chile Facultad de Ciencias Departamento de Biologýôa and Centro de Estudios Cientýôficos); Sebastian Brauchi (Universidad Austral de Chile Instituto de Fisiología); Rodolfo Madrid (Universidad de Santiago de Chile Laboratorio de Neurociencia, Departamento de Biología); Patricio Orio (Universidad de Valparaíso Centro Interdisciplinario de Neurociencia de Valparaíso)

2011-08-01

467

Advanced Cold X-Ray Source Program.  

National Technical Information Service (NTIS)

This report, the final technical report for the Advanced Cold X-Ray Source Program, describes experimental research efforts to develop plasma radiation sources (PRS) for the simulation of cold x-ray effects. On the Double- EAGLE generator we have investig...

J. C. Riordan P. D. LePell C. Deeney B. H. Failor C. A. Coverdale

2000-01-01

468

Prevention of Cold Injuries During Exercise.  

National Technical Information Service (NTIS)

In is the position of the American College of Sports Medicine that exercise can be performed safely in most cold-weather environments without incurring cold-weather injuries. The key to prevention is use of a comprehensive risk management strategy that: (...

A. J. Young E. Glickman G. G. Giesbrecht J. W. Castellani M. B. Ducharme

2006-01-01

469

Cold denaturation of proteins under high pressure  

Microsoft Academic Search

The advantageous usage of the high pressure technique in studies of cold denaturation of proteins is reviewed, with a brief explanation of the theoretical background of this universal phenomenon. Various experimental results are presented and discussed, explaining the plausible image of the cold denatured state of proteins. In order to understand more clearly this phenomenon and protein structure transition in

Shigeru Kunugi; Naoki Tanaka

2002-01-01

470

Asymptomatic myocardial ischemia following cold provocation  

Microsoft Academic Search

Cold is thought to provoke angina in patients with coronary disease either by an increase in myocardial demand or an increase in coronary vascular resistance. We investigated and compared the effects of cold pressor stimulation and symptom-limited supine bicycle exercise on regional myocardial perfusion in 35 patients with stable angina and coronary disease and in 10 normal subjects. Regional myocardial

M. J. Shea; J. E. Deanfield; C. M. deLandsheere; R. A. Wilson; M. Kensett; A. P. Selwyn

1987-01-01

471

Is It a Cold or the Flu?  

MedlinePLUS

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 ... can be life-threatening. Complications more likely in the elderly, those with chronic ... Diseases November 2008 www.niaid.nih.gov

472

Cough and Cold Medicine Abuse (For Parents)  

MedlinePLUS

... on cough and cold medicine. Why Do Kids Abuse Cough and Cold Remedies? Before the U.S. Food and Drug Administration (FDA) replaced the narcotic codeine with dextromethorphan as an over-the-counter (OTC) cough suppressant in the 1970s, teens were ...

473

Was the Cold War a Security Dilemma?  

Microsoft Academic Search

Under the security dilemma, tensions and conºicts can arise between states even when they do not intend them. Some analysts have argued that the Cold War was a classic example of a security dilemma. This article disputes that notion. Although the Cold War contained elements of a deep security dilemma, it was not purely a case in which tensions and

Robert Jervis

2001-01-01

474

Preserving Alaska's early Cold War legacy  

Microsoft Academic Search

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

J. Hoffecker; M. Whorton

1999-01-01

475

Common colds. Causes, potential cures, and treatment.  

PubMed Central

Colds are a common clinical condition, caused by a variety of pathogens. This article reviews the etiology of the cold, proposed cures, symptomatic relief, method of transmission, and advice for patients. Transmission through indirect contact, or self-inoculation, seems more common than was once thought. Experimental antiviral agents hold some promise; in the meantime, symptomatic relief is available.

Saroea, H. G.

1993-01-01

476

Cold Chemical Oxidation of Proteins  

PubMed Central

Various methods of protein footprinting use hydrogen peroxide as oxidant. Its removal by various solid-phase desalting methods, catalase treatment, or freeze-drying after the footprinting is critical to insure no uncontrolled oxidation. Although catalase treatment removes hydrogen peroxide with little loss of protein or additional protein oxidation, we discovered that freeze-drying or freezing of the protein in peroxide solution does lead to protein oxidation. Interestingly, the oxidation is not a result of freeze or thaw processes but depends on the temperature and length of time for incubation. After 2 h, apomyoglobin undergoes nearly complete single oxidation at ?80 °C and double oxidation at ?15 °C. The oxidation extents are in addition to the number of methionine residues. Minimal oxidation is observed at 4 °C and 22 °C compared to oxidation at ?80 °C or ?20 °C. The concentration of hydrogen peroxide is critical; 75 mM (0.2%) is required to oxidize > 50% of the protein at ?15 °C and 100-mM (0.3%) at ?80 °C. In addition to Met, ~ 5% of the tryptophan and tyrosine residues are oxidized as well as lower amounts of His and Phe. Oxidation of Val 68 and Val 17 (a buried residue) also occurs, with the oxidation of Val 17 likely occurring by electron transfer from one of two of the oxidized aromatic residues contacting Val 17. We describe here the need to remove the hydrogen peroxide prior to cold storage of proteins, and we also report some preliminary results pertaining to the mechanism of cold, solid-state oxidation.

Hambly, David M.; Gross, Michael L.

2010-01-01

477

Progress toward high bandwidth cold atom source  

NASA Astrophysics Data System (ADS)

Confined cold and ultra-cold atomic devices have operated at bandwidths of significantly less than 1 Hz, because the laser cooling stage and the trapping stage typically occur in the same experimental region. The low bandwidth is a current limitation of cold atom devices (e.g. interferometers). One option for a high bandwidth source of cold atoms is concurrent laser cooling in one chamber and magnetic trapping in a second chamber so the magnetic trap can be continuously maintained. This dual chamber source of atoms will at least require: optical isolation, a method for transporting between the chambers, merging new atoms with existing atoms, and providing a stable trap during all of the cooling and transport operations. We present the simulation and results of transporting atoms with high efficiency, the optimization of magnetic trapping fields, and the transfer of atoms to an atom chip for cold atom interferometry.

Squires, Matthew; Stickney, James; Baker, Paul; Carlson, Evan; Fagan-Kelly, Stefan; Miller, Steven

2010-03-01

478

Social science in the Cold War.  

PubMed

This essay examines ways in which American social science in the late twentieth century was--and was not--a creature of the Cold War. It identifies important work by historians that calls into question the assumption that all social science during the Cold War amounts to "Cold War social science." These historians attribute significant agency to social scientists, showing how they were enmeshed in both long-running disciplinary discussions and new institutional environments. Key trends in this scholarship include a broadening historical perspective to see social scientists in the Cold War as responding to the ideas of their scholarly predecessors; identifying the institutional legacies of World War II; and examining in close detail the products of extramural--especially governmental--funding. The result is a view of social science in the Cold War in which national security concerns are relevant, but with varied and often unexpected impacts on intellectual life. PMID:20718280

Engerman, David C

2010-06-01

479

21 CFR 878.4480 - Absorbable powder for lubricating a surgeon's glove.  

Code of Federal Regulations, 2010 CFR

...Absorbable powder for lubricating a surgeon's glove. 878.4480 Section 878.4480 Food...Absorbable powder for lubricating a surgeon's glove. (a) Identification. Absorbable powder for lubricating a surgeon's glove is a powder made from corn starch...

2009-04-01

480

21 CFR 878.4480 - Absorbable powder for lubricating a surgeon's glove.  

Code of Federal Regulations, 2010 CFR

...Absorbable powder for lubricating a surgeon's glove. 878.4480 Section 878.4480 Food...Absorbable powder for lubricating a surgeon's glove. (a) Identification. Absorbable powder for lubricating a surgeon's glove is a powder made from corn starch...

2010-04-01

481

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

Code of Federal Regulations, 2013 CFR

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

2013-07-01

482

Blood Pressure: Is It Affected by Cold Weather?  

MedlinePLUS

... only. Blood pressure: Is it affected by cold weather? By Mayo Clinic staff Original Article: http://www. ... Question Blood pressure: Is it affected by cold weather? Can cold weather or seasonal changes in weather ...

483

13. VIEW FROM COLD CALIBRATION BLOCKHOUSE LOOKING DOWN CONNECTING TUNNEL ...  

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

13. VIEW FROM COLD CALIBRATION BLOCKHOUSE LOOKING DOWN CONNECTING TUNNEL TO COLD CALIBRATION TEST STAND BASEMENT, SHOWING HARD WIRE CONNECTION (INSTRUMENTATION AND CONTROL). - Marshall Space Flight Center, East Test Area, Cold Calibration Test Stand, Huntsville, Madison County, AL

484

2. VIEW NORTHWEST FROM LEFT TO RIGHT: COLD CALIBRATION BLOCKHOUSE, ...  

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

2. VIEW NORTHWEST FROM LEFT TO RIGHT: COLD CALIBRATION BLOCKHOUSE, COLD CALIBRATION TEST STAND FOR FL ENGINE FOR SATURN V. EXHAUST DUCT IN FOREGROUND. - Marshall Space Flight Center, East Test Area, Cold Calibration Test Stand, Huntsville, Madison County, AL

485

1. VIEW NORTHEAST, LEFT TO RIGHT COLD CALIBRATION TEST STAND ...  

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

1. VIEW NORTHEAST, LEFT TO RIGHT COLD CALIBRATION TEST STAND COLD CALIBRATION BLOCKHOUSE IN FOREGROUND. - Marshall Space Flight Center, East Test Area, Cold Calibration Test Stand, Huntsville, Madison County, AL