Momentum deposition on Wolf-Rayet winds: Nonisotropic diffusion with effective gray opacity

NASA Astrophysics Data System (ADS)

Gayley, Kenneth G.; Owocki, Stanley P.; Cranmer, Steven R.

1995-03-01

We derive the velocity and mass-loss rate of a steady state Wolf-Rayet (WR) wind, using a nonisotropic diffusion approximation applied to the transfer between strongly overlapping spectral lines. Following the approach of Friend & Castor (1983), the line list is assumed to approximate a statistically parameterized Poisson distribution in frequency, so that photon transport is controlled by an angle-dependent, effectively gray opacity. We show the nonisotropic diffusion approximation yields good agreement with more accurate numerical treatments of the radiative transfer, while providing analytic insight into wind driving by multiple scattering. We illustrate, in particular, that multiple radiative momentum deposition does not require that photons be repeatedly reflected across substantial distances within the spherical envelope, but indeed is greatest when photons undergo a nearly local diffusion, e.g., through scattering by many lines closely spaced in frequency. Our results reiterate the view that the so-called 'momentum problem' of Wolf-Rayet winds is better characterized as an 'opacity problem' of simply identifying enough lines. One way of increasing the number of thick lines in Wolf-Rayet winds is to transfer opacity from saturated to unsaturated lines, yielding a steeper opacity distribution than that found in OB winds. We discuss the implications of this perspective for extending our approach to W-R wind models that incorporate a more fundamental treatment of the ionization and excitation processes that determine the line opacity. In particular, we argue that developing statistical descriptions of the lines to allow an improved effective opacity for the line ensemble would offer several advantages for deriving such more fundamental W-R wind models.

An Evaluation of Online Help for the NOTIS OPAC.

ERIC Educational Resources Information Center

White, Frank

1994-01-01

Discussion of online help systems in online public access catalogs (OPACs) focuses on a study that evaluated the online help system for the NOTIS (Northwestern Online Total Integrated System) OPAC. Features of the system reviewed include online functions; training features; general interface features; access points; and message content and display…

Web OPAC Interfaces: An Overview.

ERIC Educational Resources Information Center

Babu, B. Ramesh; O'Brien, Ann

2000-01-01

Discussion of Web-based online public access catalogs (OPACs) focuses on a review of six Web OPAC interfaces in use in academic libraries in the United Kingdom. Presents a checklist and guidelines of important features and functions that are currently available, including search strategies, access points, display, links, and layout. (Author/LRW)

Correlation of plume opacity with particles and sulfates from boilers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lou, J.C.; Lee, M.; Chen, K.S.

1997-07-01

The effects of emission concentrations of particulate matters and sulfates on plume opacity are investigated by in situ measurements. The studies are conducted for three processes of two coal-fired plants and one oil-fired that are all equipped with electrostatic precipitators. Flue-gas sampling and analysis include the concentrations of particles and total water soluble sulfates, particle size distribution, and flue-gas composition; while in-stack and out-of-stack opacities are determined by a transmissometer and certified smoke inspectors, respectively. Experimental results show that plume opacity outside the stack linearly correlates well with the in-stack opacity. The mixing of hot flue gas with cold ambientmore » air would result in the condensation of hygroscopic sulfuric acid aerosols and an increase about 1.6% out of typical 15--25% measured opacity. An empirical equation similar to the Beer-Lambert-Bouger form is derived for predicting the plume opacity in terms of the stack diameter and the concentrations of particles and total water soluble sulfates. Good comparisons are achieved between predictions by the empirical equation and other available field data.« less

The neutrino opacity of neutron rich matter

NASA Astrophysics Data System (ADS)

Alcain, P. N.; Dorso, C. O.

2017-05-01

The study of neutron rich matter, present in neutron star, proto-neutron stars and core-collapse supernovae, can lead to further understanding of the behavior of nuclear matter in highly asymmetric nuclei. Heterogeneous structures are expected to exist in these systems, often referred to as nuclear pasta. We have carried out a systematic study of neutrino opacity for different thermodynamic conditions in order to assess the impact that the structure has on it. We studied the dynamics of the neutrino opacity of the heterogeneous matter at different thermodynamic conditions with semiclassical molecular dynamics model already used to study nuclear multifragmentation. For different densities, proton fractions and temperature, we calculate the very long range opacity and the cluster distribution. The neutrino opacity is of crucial importance for the evolution of the core-collapse supernovae and the neutrino scattering.

Formation of Silicate and Titanium Clouds on Hot Jupiters

NASA Astrophysics Data System (ADS)

Powell, Diana; Zhang, Xi; Gao, Peter; Parmentier, Vivien

2018-06-01

We present the first application of a bin-scheme microphysical and vertical transport model to determine the size distribution of titanium and silicate cloud particles in the atmospheres of hot Jupiters. We predict particle size distributions from first principles for a grid of planets at four representative equatorial longitudes, and investigate how observed cloud properties depend on the atmospheric thermal structure and vertical mixing. The predicted size distributions are frequently bimodal and irregular in shape. There is a negative correlation between the total cloud mass and equilibrium temperature as well as a positive correlation between the total cloud mass and atmospheric mixing. The cloud properties on the east and west limbs show distinct differences that increase with increasing equilibrium temperature. Cloud opacities are roughly constant across a broad wavelength range, with the exception of features in the mid-infrared. Forward-scattering is found to be important across the same wavelength range. Using the fully resolved size distribution of cloud particles as opposed to a mean particle size has a distinct impact on the resultant cloud opacities. The particle size that contributes the most to the cloud opacity depends strongly on the cloud particle size distribution. We predict that it is unlikely that silicate or titanium clouds are responsible for the optical Rayleigh scattering slope seen in many hot Jupiters. We suggest that cloud opacities in emission may serve as sensitive tracers of the thermal state of a planet’s deep interior through the existence or lack of a cold trap in the deep atmosphere.

Evidence for dust transport in Viking IR thermal mapper opacity data

NASA Technical Reports Server (NTRS)

Martin, Terry Z.

1993-01-01

Global maps of 9-micron dust opacity derived from radiometric observations made by the Viking Orbiter IR Thermal Mapper instruments have revealed a wealth of new information about the distribution of airborne dust over 1.36 Mars years from 1976-1979. In particular, the changing dust distribution during major dust storms is of interest since the data provide a point of contact with both Earth-based observations of storm growth and with global circulation models.

Time Patterns in Remote OPAC Use.

ERIC Educational Resources Information Center

Lucas, Thomas A.

1993-01-01

Describes a transaction log analysis of the New York Public Library research libraries' OPAC (online public access catalog). Much of the remote searching occurred when the libraries were closed and was more evenly distributed than internal searching, demonstrating that remote searching could expand access and reduce peak system loads. (Contains…

THE COLUMN DENSITY DISTRIBUTION AND CONTINUUM OPACITY OF THE INTERGALACTIC AND CIRCUMGALACTIC MEDIUM AT REDSHIFT (z) = 2.4

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rudie, Gwen C.; Steidel, Charles C.; Shapley, Alice E.

2013-06-01

We present new high-precision measurements of the opacity of the intergalactic and circumgalactic medium (IGM; CGM) at (z) = 2.4. Using Voigt profile fits to the full Ly{alpha} and Ly{beta} forests in 15 high-resolution high-S/N spectra of hyperluminous QSOs, we make the first statistically robust measurement of the frequency of absorbers with H I column densities 14{approx}< log (N{sub H{sub I}}/cm{sup -2}){approx}<17.2. We also present the first measurements of the frequency distribution of H I absorbers in the volume surrounding high-z galaxies (the CGM, 300 pkpc), finding that the incidence of absorbers in the CGM is much higher than inmore » the IGM. In agreement with Rudie et al., we find that there are fractionally more high-N{sub H{sub I}} absorbers than low-N{sub H{sub I}} absorbers in the CGM compared to the IGM, leading to a shallower power law fit to the CGM frequency distribution. We use these new measurements to calculate the total opacity of the IGM and CGM to hydrogen-ionizing photons, finding significantly higher opacity than most previous studies, especially from absorbers with log (N{sub H{sub I}}/cm{sup -2}) < 17.2. Reproducing the opacity measured in our data as well as the incidence of absorbers with log (N{sub H{sub I}}/cm{sup -2})>17.2 requires a broken power law parameterization of the frequency distribution with a break near N{sub H{sub I}} Almost-Equal-To 10{sup 15} cm{sup -2}. We compute new estimates of the mean free path ({lambda}{sub mfp}) to hydrogen-ionizing photons at z{sub em} = 2.4, finding {lambda}{sub mfp} = 147 {+-} 15 Mpc when considering only IGM opacity. If instead, we consider photons emanating from a high-z star-forming galaxy and account for the local excess opacity due to the surrounding CGM of the galaxy itself, the mean free path is reduced to {lambda}{sub mfp} = 121 {+-} 15 Mpc. These {lambda}{sub mfp} measurements are smaller than recent estimates and should inform future studies of the metagalactic UV background and of ionizing sources at z Almost-Equal-To 2-3.« less

Effects of Nongray Opacity on Radiatively Driven Wolf-Rayet Winds

NASA Astrophysics Data System (ADS)

Onifer, A. J.; Gayley, K. G.

2002-05-01

Wolf-Rayet winds are characterized by their large momentum fluxes, and simulations of radiation driving have been increasingly successful in modeling these winds. Simple analytic approaches that help understand the most critical processes for copious momentum deposition already exist in the effectively gray approximation, but these have not been extended to more realistic nongray opacities. With this in mind, we have developed a simplified theory for describing the interaction of the stellar flux with nongray wind opacity. We replace the detailed line list with a set of statistical parameters that are sensitive not only to the strength but also the wavelength distribution of lines, incorporating as a free parameter the rate of photon frequency redistribution. We label the resulting flux-weighted opacity the statistical Sobolev- Rosseland (SSR) mean, and explore how changing these various statistical parameters affects the flux/opacity interaction. We wish to acknowledge NSF grant AST-0098155

X ray opacity in cluster cooling flows

NASA Technical Reports Server (NTRS)

Wise, Michael W.; Sarazin, Craig L.

1993-01-01

We have calculated the emergent x-ray properties for a set of spherically symmetric, steady-state cluster cooling flow models including the effects of radiative transfer. Opacity due to resonant x-ray lines, photoelectric absorption, and electron scattering have been included in these calculations, and homogeneous and inhomogeneous gas distributions were considered. The effects of photoionization opacity are small for both types of models. In contrast, resonant line optical depths can be quite high in both homogeneous and inhomogeneous models. The presence of turbulence in the gas can significantly lower the line opacity. We find that integrated x-ray spectra for the flow cooling now are only slightly affected by radiative transfer effects. However x-ray line surface brightness profiles can be dramatically affected by radiative transfer. Line profiles are also strongly affected by transfer effects. The combined effects of opacity and inflow cause many of the lines in optically thick models to be asymmetrical.

Sensitivity of simulated Martian atmospheric temperature to prescribed dust opacity distribution: Comparison of model results with reconstructed data from Mars Exploration Rover missions

NASA Astrophysics Data System (ADS)

Natarajan, Murali; Dwyer Cianciolo, Alicia; Fairlie, T. Duncan; Richardson, Mark I.; McConnochie, Timothy H.

2015-11-01

We use the Mars Weather Research and Forecasting (MarsWRF) general circulation model to simulate the atmospheric structure corresponding to the landing location and time of the Mars Exploration Rovers (MER) Spirit (A) and Opportunity (B) in 2004. The multiscale capability of MarsWRF facilitates high-resolution nested model runs centered near the landing site of each of the rovers. Dust opacity distributions based on measurements by Thermal Emission Spectrometer (TES) aboard the Mars Global Surveyor spacecraft, and those from an old version of the Mars Climate Database (MCD v3.1 released in 2001) are used to study the sensitivity of the model temperature profile to variations in the dust prescription. The reconstructed entry, descent, and landing (EDL) data from the rover missions are used for comparisons. We show that the model using dust opacity from TES limb and nadir data for the year of MER EDL, Mars Year 26 (MY26), yields temperature profiles in closer agreement with the reconstructed data than the prelaunch EDL simulations and models using other dust opacity specifications. The temperature at 100 Pa from the model (MY26) and the reconstruction are within 5°K. These results highlight the role of vertical dust opacity distribution in determining the atmospheric thermal structure. Similar studies involving data from past missions and models will be useful in understanding the extent to which atmospheric variability is captured by the models and in developing realistic preflight characterization required for future lander missions to Mars.

Chest Radiological Findings of Patients With Severe H1N1 Pneumonia Requiring Intensive Care.

PubMed

Rohani, Payam; Jude, Cecilia M; Chan, Kelvin; Barot, Nikhil; Kamangar, Nader

2016-01-01

A new strain of human influenza A (H1N1) virus originated from Mexico in 2009 and spread to more than 190 countries and territories. The World Health Organization (WHO) declared it a level 6 (highest level) pandemic. In August 2010, WHO announced that the H1N1 2009 influenza virus had moved into the postpandemic period. The WHO also declared that this flu strain is expected to continue to circulate as a seasonal virus "for some years to come." The objective of this study is to describe the chest radiographic and computed tomography (CT) findings of patients with severe H1N1 pneumonia admitted to the intensive care unit (ICU) during the 2009 pandemic. Patients with severe H1N1 pneumonia requiring ICU admission have extensive radiographic and CT abnormalities. Eighteen patients, aged 23 to 62 (mean 41), admitted to the ICU at UCLA-Olive View Medical Center with a primary diagnosis of pandemic H1N1 infection, confirmed either via rapid influenza detection test or by real-time reverse transcriptase polymerase chain reaction assay, formed the study population. All patients had chest x-ray (CXR) within 24 hours of admission and 5 patients had CT examinations. In this retrospective study, images were evaluated for the pattern (ground-glass opacities, consolidation, reticular opacities, and nodular opacities), distribution (unilateral/bilateral, upper/middle/lower lung zone, and central/peripheral/peribronchovascular), and extent (focal/multifocal/diffuse; number of lung zones) of abnormalities. All (100%) patients had abnormal CXR and CT studies. The predominant radiographic findings were ground-glass opacities (16 of 18; 89%), consolidation (16 of 18; 89%), and reticular opacities (6 of 18, 33%). The radiographic abnormalities were bilateral in 17 (94%) patients; involved lower lung distribution in 18 (100%) patients, and mid and lower lung distribution in 16 (89%) patients. Radiographic abnormalities were peribronchovascular in 11 (61%) patients and multifocal in 10 (56%). Sixteen (89%) patients had extensive abnormalities involving 3 or more lung zones. The patients requiring mechanical ventilation had a higher incidence of bilateral, diffuse consolidation in a peribronchovascular distribution on chest radiographs. The predominant CT abnormalities were consolidation (5 of 5; 100%), ground-glass opacities (5 of 5; 100%), and nodular opacities (3 of 5, 60%). The CT findings were peribronchovascular and multifocal in 4 (80%) patients and extensive and bilateral in all (100%) patients. Patients with H1N1 pneumonia admitted to the ICU had bilateral, extensive CXR, and CT abnormalities. Consolidations and ground-glass opacities were the most common imaging findings, predominantly affecting mid and lower lung zones. Imaging abnormalities were peribronchovascular and multifocal in a majority of patients. © The Author(s) 2014.

The Column Density Distribution and Continuum Opacity of the Intergalactic and Circumgalactic Medium at Redshift langzrang = 2.4

NASA Astrophysics Data System (ADS)

Rudie, Gwen C.; Steidel, Charles C.; Shapley, Alice E.; Pettini, Max

2013-06-01

We present new high-precision measurements of the opacity of the intergalactic and circumgalactic medium (IGM; CGM) at langzrang = 2.4. Using Voigt profile fits to the full Lyα and Lyβ forests in 15 high-resolution high-S/N spectra of hyperluminous QSOs, we make the first statistically robust measurement of the frequency of absorbers with H I column densities 14 \\lesssim log (N_H\\,\\scriptsize{ I}/ {cm}^{-2}) \\lesssim 17.2. We also present the first measurements of the frequency distribution of H I absorbers in the volume surrounding high-z galaxies (the CGM, 300 pkpc), finding that the incidence of absorbers in the CGM is much higher than in the IGM. In agreement with Rudie et al., we find that there are fractionally more high-N H I absorbers than low-N H I absorbers in the CGM compared to the IGM, leading to a shallower power law fit to the CGM frequency distribution. We use these new measurements to calculate the total opacity of the IGM and CGM to hydrogen-ionizing photons, finding significantly higher opacity than most previous studies, especially from absorbers with log (N_H\\,\\scriptsize{ I}/ {cm}^{-2}) < 17.2. Reproducing the opacity measured in our data as well as the incidence of absorbers with log (N_H\\,\\scriptsize{ I}/ {cm}^{-2}) \\gt 17.2 requires a broken power law parameterization of the frequency distribution with a break near N H I ≈1015 cm-2. We compute new estimates of the mean free path (λmfp) to hydrogen-ionizing photons at z em = 2.4, finding λmfp = 147 ± 15 Mpc when considering only IGM opacity. If instead, we consider photons emanating from a high-z star-forming galaxy and account for the local excess opacity due to the surrounding CGM of the galaxy itself, the mean free path is reduced to λmfp = 121 ± 15 Mpc. These λmfp measurements are smaller than recent estimates and should inform future studies of the metagalactic UV background and of ionizing sources at z ≈ 2-3. Based on data obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration, and was made possible by the generous financial support of the W. M. Keck Foundation.

Ionization competition effects on population distribution and radiative opacity of mixture plasmas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Yongjun; Gao, Cheng; Tian, Qinyun

2015-11-15

Ionization competition arising from the electronic shell structures of various atomic species in the mixture plasmas was investigated, taking SiO{sub 2} as an example. Using a detailed-level-accounting approximation, we studied the competition effects on the charge state population distribution and spectrally resolved and Planck and Rosseland mean radiative opacities of mixture plasmas. A set of coupled equations for ionization equilibria that include all components of the mixture plasmas are solved to determine the population distributions. For a given plasma density, competition effects are found at three distinct temperature ranges, corresponding to the ionization of M-, L-, and K-shell electrons ofmore » Si. Taking the effects into account, the spectrally resolved and Planck and Rosseland mean opacities are systematically investigated over a wide range of plasma densities and temperatures. For a given mass density, the Rosseland mean decreases monotonically with plasma temperature, whereas Planck mean does not. Although the overall trend is a decrease, the Planck mean increases over a finite intermediate temperature regime. A comparison with the available experimental and theoretical results is made.« less

Recovering Galaxy Rotation Speeds from Irregular Emission Profiles

NASA Astrophysics Data System (ADS)

Lavezzi, T. E.; Dickey, J. M.

1997-12-01

We simulate extragalactic emission spectra in order to determine whether the spectra of molecular gas measure the full velocity of disk rotation, despite their confined gas distributions. We present synthetic emission profiles to determine the effects on profile shapes due to factors such as telescope beam size. gas distribution, opacity, and pointing errors. We find that linewidths cease to be useful if the telescope beam resolves the solid body rotation region of the galaxy disk, or if the disk is very optically thick. Opacity is more problematic for edge-on galaxies; at lower optical depths, we find that very often a trough is created in the center of the emission line. We establish guidelines for rejecting spectra as unreliable disk-velocity indicators, and determine what corrections to the measured line widths at 20% and 50% of the peak intensity are best to recover twice the disk rotation velocity. Following the procedure of Bicay & Giovanelli (1986, AJ, 91, 705) we find that the 50% of peak intensity threshold for measuring linewidths (W50p, or FWHM) is the most robust, yielding the smallest measurement errors as a function of signal to noise, and requires the smallest turbulence corrections.

A Generalised Porosity Formalism for Isotropic and Anisotropic Effective Opacity and Its Effects on X-ray Line Attenuation in Clumped O Star Winds

NASA Technical Reports Server (NTRS)

Sundqvist, Jon O.; Owocki, Stanley P.; Cohen, David H.; Leutenegger, Maurice A.; Townsend, Richard H. D.

2002-01-01

We present a generalised formalism for treating the porosity-associated reduction in continuum opacity that occurs when individual clumps in a stochastic medium become optically thick. As in previous work, we concentrate on developing bridging laws between the limits of optically thin and thick clumps. We consider geometries resulting in either isotropic or anisotropic effective opacity, and, in addition to an idealised model in which all clumps have the same local overdensity and scale, we also treat an ensemble of clumps with optical depths set by Markovian statistics. This formalism is then applied to the specific case of bound-free absorption of X- rays in hot star winds, a process not directly affected by clumping in the optically thin limit. We find that the Markov model gives surprisingly similar results to those found previously for the single clump model, suggesting that porous opacity is not very sensitive to details of the assumed clump distribution function. Further, an anisotropic effective opacity favours escape of X-rays emitted in the tangential direction (the venetian blind effect), resulting in a bump of higher flux close to line centre as compared to profiles computed from isotropic porosity models. We demonstrate how this characteristic line shape may be used to diagnose the clump geometry, and we confirm previous results that for optically thick clumping to significantly influence X-ray line profiles, very large porosity lengths, defined as the mean free path between clumps, are required. Moreover, we present the first X-ray line profiles computed directly from line-driven instability simulations using a 3-D patch method, and find that porosity effects from such models also are very small. This further supports the view that porosity has, at most, a marginal effect on X-ray line diagnostics in O stars, and therefore that these diagnostics do indeed provide a good clumping insensitive method for deriving O star mass-loss rates.

IR spectral properties of dust and ice at the Mars south polar cap

NASA Astrophysics Data System (ADS)

Titus, T. N.; Kieffer, H. H.

2001-11-01

Removal of atmospheric dust effects is required to derive surface IR spectral emissivity. Commonly, the atmospheric-surface separation is based on radiative transfer (RT) spectral inversion methods using nadir-pointing observations. This methodology depends on a priori knowledge of the spectral shape of each atmospheric aerosol (e.g. dust or water ice) and a large thermal contrast between the surface and atmosphere. RT methods fail over the polar caps due to low thermal contrast between the atmosphere and the surface. We have used multi-angle Emission Phase Function (EPF) observations to estimate the opacity spectrum of dust over the springtime south polar cap and the underlying surface radiance, and thus, the surface emissivity. We include a few EPFs from Hellas Basin as a basis for comparisons between the spectral shape of polar and non-polar dust. Surface spectral emissivities over the seasonal cap are compared to CO2 models. Our results show that the spectral shape of the polar dust opacity is not constant, but is a two-parameter family that can be characterized by the 9 um and 20 um opacities. The 9 um opacity varies from 0.15 to 0.45 and characterizes the overall atmospheric conditions. The 9 um to 20 um opacity ratio varies from 2.0 to 5.1, suggesting changes in dust size distribution over the polar caps. Derived surface temperatures from the EPFs confirm that the slightly elevated temperatures (relative to CO2 frost temperature) observed in ``cryptic'' regions are a surface effect, not atmospheric. Comparison of broad-band reflectivity and surface emissivities to model spectra suggest the bright regions (e.g. perennial cap, Mountains of Mitchell) have higher albedos due to a thin surface layer of fine-grain CO2 (perhaps either frost or fractured ice) with an underlying layer of either coarse grain or slab CO2 ice.

A Generalised Porosity Formalism for Isotropic and Anisotropic Effective Opacity and its Effects on X-ray Line Attenuation in Clumped O Star Winds

NASA Technical Reports Server (NTRS)

Sundqvist, Jon O.; Owocki, Stanley P.; Cohen, David H.; Leutenegger, Maurice A.

2011-01-01

We present a generalised formalism for treating the porosity-associated reduction in continuum opacity that occurs when individual clumps in a stochastic medium become optically thick. As in previous work, we concentrate on developing bridging laws between the limits of optically thin and thick clumps. We consider geometries resulting in either isotropic or anisotropic effective opacity, and, in addition to an idealised model in which all clumps have the same local overdensity and scale, we also treat an ensemble of clumps with optical depths set by Markovian statistics. This formalism is then applied to the specific case of bound-free absorption of X- rays in hot star winds, a process not directly affected by clumping in the optically thin limit. We find that the Markov model gives surprisingly similar results to those found previously for the single clump model, suggesting that porous opacity is not very sensitive to details of the assumed clump distribution function. Further, an anisotropic effective opacity favours escape of X-rays emitted in the tangential direction (the venetian blind effect), resulting in a bump of higher flux close to line centre as compared to profiles computed from isotropic porosity models. We demonstrate how this characteristic line shape may be used to diagnose the clump geometry, and we confirm previous results that for optically thick clumping to significantly influence X-ray line profiles, very large porosity lengths, defined as the mean free path between clumps, are required. Moreover, we present the first X-ray line profiles computed directly from line-driven instability simulations using a 3-D patch method, and find that porosity effects from such models also are very small. This further supports the view that porosity has, at most, a marginal effect on X-ray line diagnostics in O stars, and therefore that these diagnostics do indeed provide a good clumping insensitive method for deriving O star mass-loss rates.

Dust observations by PFS on Mars Express

NASA Astrophysics Data System (ADS)

Zasova, L. V.; Formisano, V.; Moroz, V. I.; Grassi, D.; Ignatiev, N. I.; Blecka, M. I.; Maturilli, A.; Palomba, E.; Piccioni, G.; Pfs Team

Dust is always present in the Martian atmosphere with opacity, which changes from values below 0.1 (at 9 μ m) up to several units during the dust storms. From the thermal IR (LW channel of PFS) the dust opacity is retrieved in a self consistent way together with the temperature profile from the same spectrum A preliminary investigation along the orbit, which comes through Hellas, shows that the value of dust opacity anticorrelates with surface altitude. From -70 to +25 of latitude the vertical dust distribution follows the exponential low with the scale of 12 km, which corresponds to the gaseous scale height near noon and indicates for well mixed condition. The dust opacity, corresponding to the zero surface altitude, is found of 0.25+-0.05. More detailed investigations of all available data will be presented, including analysis of both short- and long- wavelength spectra of PFS.

Model Stellar Atmospheres and Real Stellar Atmospheres and Status of the ATLAS12 Opacity Sampling Program and of New Programs for Rosseland and for Distribution Function Opacity

NASA Technical Reports Server (NTRS)

Kurucz, Robert L.

1996-01-01

I discuss errors in theory and in interpreting observations that are produced by the failure to consider resolution in space, time, and energy. I discuss convection in stellar model atmospheres and in stars. Large errors in abundances are possible such as the factor of ten error in the Li abundance for extreme Population II stars. Finally I discuss the variation of microturbulent velocity with depth, effective temperature, gravity, and abundance. These variations must be dealt with in computing models and grids and in any type of photometric calibration. I have also developed a new opacity-sampling version of my model atmosphere program called ATLAS12. It recognizes more than 1000 atomic and molecular species, each in up to 10 isotopic forms. It can treat all ions of the elements up through Zn and the first 5 ions of heavier elements up through Es. The elemental and isotopic abundances are treated as variables with depth. The fluxes predicted by ATLAS12 are not accurate in intermediate or narrow bandpass intervals because the sample size is too small. A special stripped version of the spectrum synthesis program SYNTHE is used to generate the surface flux for the converged model using the line data on CD-ROMs 1 and 15. ATLAS12 can be used to produce improved models for Am and Ap stars. It should be very useful for investigating diffusion effects in atmospheres. It can be used to model exciting stars for H II regions with abundances consistent with those of the H II region. These programs and line files will be distributed on CD-ROMs.

Nongrayness Effects in Wolf-Rayet Wind Momentum Deposition

NASA Astrophysics Data System (ADS)

Onifer, A. J.; Gayley, K. G.

2004-05-01

Wolf-Rayet winds are characterized by their large momentum fluxes and optically thick winds. A simple analytic approach that helps to understand the most critical processes is the effecively gray approximation, but this has not been generalized to more realistic nongray opacities. We have developed a simplified theory for describing the interaction of the stellar flux with nongray wind opacity. We replace the detailed line list with a set of statistical parameters that are sensitive to the line strengths as well as the wavelength distribution of lines. We determine these statistical parameters for several real line lists, exploring the effects of temperature and density changes on the efficiency of momentum driving relative to gray opacity. We wish to acknowledge NSF grant AST-0098155.

Continuous opacity from Ne^-

NASA Astrophysics Data System (ADS)

John, T. L.

1996-04-01

Free-free absorption coefficients of the negative neon ion are calculated by the phase-shift approximation based on multiconfiguration Hartree-Fock continuum wave functions. These wave functions accurately account for electron-neon correlation and polarization, and yield scattering cross-sections in excellent agreement with the latest experimental values. The coefficients are expected to give the best current estimates of Ne^- continuous absorption. We find that Ne^- makes only a small contribution (less than 0.3 per cent) to stellar opacities, including hydrogen-deficient stars with enhanced Ne abundances.

Measurements of the K -Shell Opacity of a Solid-Density Magnesium Plasma Heated by an X-Ray Free-Electron Laser

DOE PAGES

Preston, T. R.; Vinko, S. M.; Ciricosta, O.; ...

2017-08-25

We present measurements of the spectrally resolved x rays emitted from solid-density magnesium targets of varying sub-μm thicknesses isochorically heated by an x-ray laser. The data exhibit a largely thickness independent source function, allowing the extraction of a measure of the opacity to K-shell x rays within well-defined regimes of electron density and temperature, extremely close to local thermodynamic equilibrium conditions. The deduced opacities at the peak of the Kα transitions of the ions are consistent with those predicted by detailed atomic-kinetics calculations.

MAFAGS-OS: New opacity sampling model atmospheres for A, F and G stars. I. The model and the solar flux

NASA Astrophysics Data System (ADS)

Grupp, F.

2004-06-01

We present a new opacity sampling model atmosphere code, named MAFAGS-OS. This code, designed for stars reaching from A0 down to G9 on a solar and metal poor main sequence and up to an evolutionary stage represented by the turnoff is introduced in its basic input physics and modelling techniques. Fe I bound-free cross-sections of \\citet{BAUTISTA97} are used and convection is treated according to \\citet{canuto91}. An αcm-parameter for the efficiency of convection of 0.82 is used as determined by \\citet{BERNKOPF98} from stellar evolution requirements. Within the process of opacity sampling, special attention is drawn to the matter of line selection. We show that a selection criterion, in which lines are chosen by their opacity weighted relative to the continuous background opacity, is useful and valid. The solar model calculated using this new code is shown to fit the measured solar flux distribution. It is also tested against the measured solar colours and leads to U-B=0.21 and B-V=0.64, in good agreement with observation. Comparison with measured centre-to-limb continuum data show only small improvement with respect to opacity-sampling type model atmospheres. This is the first of a series of 2 papers. Paper II will deal with the matter of temperature determination using Balmer lines and the infrared-flux method; furthermore it will present three ``standard'' stars analysed using this new model.

Light Scattering by Fractal Dust Aggregates. II. Opacity and Asymmetry Parameter

NASA Astrophysics Data System (ADS)

Tazaki, Ryo; Tanaka, Hidekazu

2018-06-01

Optical properties of dust aggregates are important at various astrophysical environments. To find a reliable approximation method for optical properties of dust aggregates, we calculate the opacity and the asymmetry parameter of dust aggregates by using a rigorous numerical method, the T-Matrix Method, and then the results are compared to those obtained by approximate methods: the Rayleigh–Gans–Debye (RGD) theory, the effective medium theory (EMT), and the distribution of hollow spheres method (DHS). First of all, we confirm that the RGD theory breaks down when multiple scattering is important. In addition, we find that both EMT and DHS fail to reproduce the optical properties of dust aggregates with fractal dimensions of 2 when the incident wavelength is shorter than the aggregate radius. In order to solve these problems, we test the mean field theory (MFT), where multiple scattering can be taken into account. We show that the extinction opacity of dust aggregates can be well reproduced by MFT. However, it is also shown that MFT is not able to reproduce the scattering and absorption opacities when multiple scattering is important. We successfully resolve this weak point of MFT, by newly developing a modified mean field theory (MMF). Hence, we conclude that MMF can be a useful tool to investigate radiative transfer properties of various astrophysical environments. We also point out an enhancement of the absorption opacity of dust aggregates in the Rayleigh domain, which would be important to explain the large millimeter-wave opacity inferred from observations of protoplanetary disks.

Size distribution and concentration of soot generated in oil and gas-fired residential boilers under different combustion conditions

NASA Astrophysics Data System (ADS)

Jiménez, Santiago; Barroso, Jorge; Pina, Antonio; Ballester, Javier

2016-05-01

In spite of the relevance of residential heating burners in the global emission of soot particles to the atmosphere, relatively little information on their properties (concentration, size distribution) is available in the literature, and even less regarding the dependence of those properties on the operating conditions. Instead, the usual procedure to characterize those emissions is to measure the smoke opacity by several methods, among which the blackening of a paper after filtering a fixed amount of gas (Bacharach test) is predominant. In this work, the size distributions of the particles generated in the combustion of a variety of gaseous and liquid fuels in a laboratory facility equipped with commercial burners have been measured with a size classifier coupled to a particle counter in a broad range of operating conditions (air excesses), with simultaneous determination of the Bacharach index. The shape and evolution of the distribution with progressively smaller oxygen concentrations depends essentially on the state of the fuel: whereas the combustion of the gases results in monomodal distributions that 'shift' towards larger diameters, in the case of the gas-oils an ultrafine mode is always observed, and a secondary mode of coarse particle grows in relevance. In both cases, there is a strong, exponential correlation between the total mass concentration and the Bacharach opacity index, quite similar for both groups of fuels. The empirical expressions proposed may allow other researchers to at least estimate the emissions of numerous combustion facilities routinely characterized by their smoke opacities.

Autofluorescence imaging of macular pigment: influence and correction of ocular media opacities

NASA Astrophysics Data System (ADS)

Sharifzadeh, Mohsen; Obana, Akira; Gohto, Yuko; Seto, Takahiko; Gellermann, Werner

2014-09-01

The healthy adult human retina contains in its macular region a high concentration of blue-light absorbing carotenoid compounds, known as macular pigment (MP). Consisting of the carotenoids lutein, zeaxanthin, and meso-zeaxanthin, the MP is thought to shield the vulnerable tissue layers in the retina from light-induced damage through its function as an optical attenuator and to protect the tissue cells within its immediate vicinity through its function as a potent antioxidant. Autofluorescence imaging (AFI) is emerging as a viable optical method for MP screening of large subject populations, for tracking of MP changes over time, and for monitoring MP uptake in response to dietary supplementation. To investigate the influence of ocular media opacities on AFI-based MP measurements, in particular, the influence of lens cataracts, we conducted a clinical trial with a large subject population (93 subjects) measured before and after cataract surgery. General AFI image contrast, retinal blood vessel contrast, and presurgery lens opacity scores [Lens Opacities Classification System III (LOCS III)] were investigated as potential predictors for image degradation. These clinical results show that lens cataracts can severely degrade the achievable pixel contrasts in the AFI images, which results in nominal MP optical density levels that are artifactually reduced. While LOCS III scores and blood vessel contrast are found to be only a weak predictor for this effect, a strong correlation exists between the reduction factor and the image contrast, which can be quantified via pixel intensity histogram parameters. Choosing the base width of the histogram, the presence or absence of ocular media opacities can be determined and, if needed, the nominal MP levels can be corrected with factors depending on the strength of the opacity.

Modeling the Hydrological Cycle in the Atmosphere of Mars: Influence of a Bimodal Size Distribution of Aerosol Nucleation Particles

NASA Astrophysics Data System (ADS)

Shaposhnikov, Dmitry S.; Rodin, Alexander V.; Medvedev, Alexander S.; Fedorova, Anna A.; Kuroda, Takeshi; Hartogh, Paul

2018-02-01

We present a new implementation of the hydrological cycle scheme into a general circulation model of the Martian atmosphere. The model includes a semi-Lagrangian transport scheme for water vapor and ice and accounts for microphysics of phase transitions between them. The hydrological scheme includes processes of saturation, nucleation, particle growth, sublimation, and sedimentation under the assumption of a variable size distribution. The scheme has been implemented into the Max Planck Institute Martian general circulation model and tested assuming monomodal and bimodal lognormal distributions of ice condensation nuclei. We present a comparison of the simulated annual variations, horizontal and vertical distributions of water vapor, and ice clouds with the available observations from instruments on board Mars orbiters. The accounting for bimodality of aerosol particle distribution improves the simulations of the annual hydrological cycle, including predicted ice clouds mass, opacity, number density, and particle radii. The increased number density and lower nucleation rates bring the simulated cloud opacities closer to observations. Simulations show a weak effect of the excess of small aerosol particles on the simulated water vapor distributions.

Mars dust and cloud opacities and scattering properties

NASA Technical Reports Server (NTRS)

Clancy, R. T.; Lee, S. W.

1992-01-01

We have recently completed an analysis of the visible emission-phase function (EPF) sequences obtained with the solar-band channel of the Infrared Thermal Mapping (IRTM) instrument onboard the two Viking Orbiters. Roughly 100 of these EPF sequences were gathered during the 1977-1980 period, in which the total broadband (.3-3.0 microns) reflectances of the atmosphere/surface above specific locations on Mars were measured versus emission angle as the spacecraft passed overhead. A multiple scattering radiative transfer program was employed to model the EPF observations in terms of the optical depths of dust/clouds, their single scattering albedos and phase functions, and the Lambert albedos and phase coefficient of the underlying surfaces. Due to the predominance of atmospheric scattering at large atmospheric pathlengths and/or large dust opacities, we were able to obtain strong constraints on the scattering properties of dust/clouds and their opacities for a wide range of latitudes, longitudes, and seasons on Mars.

Model-independent Constraints on Cosmic Curvature and Opacity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Guo-Jian; Li, Zheng-Xiang; Xia, Jun-Qing

2017-09-20

In this paper, we propose to estimate the spatial curvature of the universe and the cosmic opacity in a model-independent way with expansion rate measurements, H ( z ), and type Ia supernova (SNe Ia). On the one hand, using a nonparametric smoothing method Gaussian process, we reconstruct a function H ( z ) from opacity-free expansion rate measurements. Then, we integrate the H ( z ) to obtain distance modulus μ {sub H}, which is dependent on the cosmic curvature. On the other hand, distances of SNe Ia can be determined by their photometric observations and thus are opacity-dependent.more » In our analysis, by confronting distance moduli μ {sub H} with those obtained from SNe Ia, we achieve estimations for both the spatial curvature and the cosmic opacity without any assumptions for the cosmological model. Here, it should be noted that light curve fitting parameters, accounting for the distance estimation of SNe Ia, are determined in a global fit together with the cosmic opacity and spatial curvature to get rid of the dependence of these parameters on cosmology. In addition, we also investigate whether the inclusion of different priors for the present expansion rate ( H {sub 0}: global estimation, 67.74 ± 0.46 km s{sup −1} Mpc{sup −1}, and local measurement, 73.24 ± 1.74 km s{sup −1} Mpc{sup −1}) exert influence on the reconstructed H ( z ) and the following estimations of the spatial curvature and cosmic opacity. Results show that, in general, a spatially flat and transparent universe is preferred by the observations. Moreover, it is suggested that priors for H {sub 0} matter a lot. Finally, we find that there is a strong degeneracy between the curvature and the opacity.« less

Atmospheric imaging results from the Mars Exploration Rovers

NASA Astrophysics Data System (ADS)

Lemmon, M.; Athena Science Team

The Athena science payload of the Spirit and Opportunity Mars Exploration Rovers contains instruments capable of measuring radiometric properties of the Martian atmosphere in the visible and the thermal infrared. Remote sensing instruments include Pancam, a color panoramic camera covering 0.4-1.0 microns, and Mini-TES, a thermal infrared spectrometer covering 5-29 microns. Results from atmospheric imaging by Pancam will be covered here. Visible and near-infrared aerosol opacity is monitored by direct solar imaging. Early results show dust opacity near 1 when both rovers landed. Both Spirit and Opportunity have seen dust opacity fall with time, somewhat faster at Spirit's Gusev crater landing site. Diurnal variations are also being monitored at both sites. There is no direct probe of the dust's vertical distribution, but images of the Sun near the horizon and of the twilight will provide constraints on the dust distribution. Dust optical properties and a cross-section weighted aerosol size will be estimated from Pancam images of the sky at varying geometries and times of day. A series of sky imaging sequences has been run with varying illumination geometry. The observations are similar to those reported for Mars Pathfinder.

The Christiansen Effect in Saturn's narrow dusty rings and the spectral identification of clumps in the F ring

USGS Publications Warehouse

Hedman, M.M.; Nicholson, P.D.; Showalter, M.R.; Brown, R.H.; Buratti, B.J.; Clark, R.N.; Baines, K.; Sotin, Christophe

2011-01-01

Stellar occultations by Saturn's rings observed with the Visual and Infrared Mapping Spectrometer (VIMS) onboard the Cassini spacecraft reveal that dusty features such as the F ring and the ringlets in the Encke and the Laplace Gaps have distinctive infrared transmission spectra. These spectra show a narrow optical depth minimum at wavelengths around 2.87??m. This minimum is likely due to the Christiansen Effect, a reduction in the extinction of small particles when their (complex) refractive index is close to that of the surrounding medium. Simple Mie-scattering models demonstrate that the strength of this opacity dip is sensitive to the size distribution of particles between 1 and 100??m across. Furthermore, the spatial resolution of the occultation data is sufficient to reveal variations in the transmission spectra within and among these rings. In both the Encke Gap ringlets and F ring, the opacity dip weakens with increasing local optical depth, which is consistent with the larger particles being concentrated near the cores of these rings. The Encke Gap ringlets also show systematically weaker opacity dips than the F ring and Laplace Gap ringlet, implying that the former has a smaller fraction of grains less than ~30??m across. However, the strength of the opacity dip varies most dramatically within the F ring; certain compact regions of enhanced optical depth lack an opacity dip and therefore appear to have a greatly reduced fraction of grains in the few-micron size range. Such spectrally-identifiable structures probably represent a subset of the compact optically-thick clumps observed by other Cassini instruments. These variations in the ring's particle size distribution can provide new insights into the processes of grain aggregation, disruption and transport within dusty rings. For example, the unusual spectral properties of the F-ring clumps could perhaps be ascribed to small grains adhering onto the surface of larger particles in regions of anomalously low velocity dispersion. ?? 2011 Elsevier Inc.

The role of transparency in da Vinci stereopsis.

PubMed

Zannoli, Marina; Mamassian, Pascal

2011-10-15

The majority of natural scenes contains zones that are visible to one eye only. Past studies have shown that these monocular regions can be seen at a precise depth even though there are no binocular disparities that uniquely constrain their locations in depth. In the so-called da Vinci stereopsis configuration, the monocular region is a vertical line placed next to a binocular rectangular occluder. The opacity of the occluder has been mentioned to be a necessary condition to obtain da Vinci stereopsis. However, this opacity constraint has never been empirically tested. In the present study, we tested whether da Vinci stereopsis and perceptual transparency can interact using a classical da Vinci configuration in which the opacity of the occluder varied. We used two different monocular objects: a line and a disk. We found no effect of the opacity of the occluder on the perceived depth of the monocular object. A careful analysis of the distribution of perceived depth revealed that the monocular object was perceived at a depth that increased with the distance between the object and the occluder. The analysis of the skewness of the distributions was not consistent with a double fusion explanation, favoring an implication of occlusion geometry in da Vinci stereopsis. A simple model that includes the geometry of the scene could account for the results. In summary, the mechanism responsible to locate monocular regions in depth is not sensitive to the material properties of objects, suggesting that da Vinci stereopsis is solved at relatively early stages of disparity processing. Copyright © 2011 Elsevier Ltd. All rights reserved.

Elasticity-based three dimensional ultrasound real-time volume rendering

NASA Astrophysics Data System (ADS)

Boctor, Emad M.; Matinfar, Mohammad; Ahmad, Omar; Rivaz, Hassan; Choti, Michael; Taylor, Russell H.

2009-02-01

Volumetric ultrasound imaging has not gained wide recognition, despite the availability of real-time 3D ultrasound scanners and the anticipated potential of 3D ultrasound imaging in diagnostic and interventional radiology. Their use, however, has been hindered by the lack of real-time visualization methods that are capable of producing high quality 3D rendering of the target/surface of interest. Volume rendering is a known visualization method, which can display clear surfaces out of the acquired volumetric data, and has an increasing number of applications utilizing CT and MRI data. The key element of any volume rendering pipeline is the ability to classify the target/surface of interest by setting an appropriate opacity function. Practical and successful real-time 3D ultrasound volume rendering can be achieved in Obstetrics and Angio applications where setting these opacity functions can be done rapidly, and reliably. Unfortunately, 3D ultrasound volume rendering of soft tissues is a challenging task due to the presence of significant amount of noise and speckle. Recently, several research groups have shown the feasibility of producing 3D elasticity volume from two consecutive 3D ultrasound scans. This report describes a novel volume rendering pipeline utilizing elasticity information. The basic idea is to compute B-mode voxel opacity from the rapidly calculated strain values, which can also be mixed with conventional gradient based opacity function. We have implemented the volume renderer using GPU unit, which gives an update rate of 40 volume/sec.

[Toxicity of ethylene oxide on the crystalline lense in an occupational milieu. Difficulty of epidemiologic surveys of cataract].

PubMed

Deschamps, D; Leport, M; Cordier, S; Laurent, A M; Festy, B; Hamard, H; Renard, G; Pouliquen, Y; Conso, F

1990-01-01

Ethylene oxide is a sterilizing gas for heat-sensitive materials. Eight cases of subcapsular cataract were attributed to this compound from 1982 to 1985. This epidemiological study was conducted in 55 persons to determine the prevalence of lens opacities and cataracts in workers exposed to this gas. The 21 persons of more than 45 years of age were then compared to 16 non-exposed persons matched for age and gender. Lens opacities (independently of visual acuity) were observed in 19 of the 55 exposed. Among exposed and non-exposed persons of more than 45 years of age, there were no significantly differences with regard to the following characteristics of lens opacities: prevalence (13 in the 21 exposed; 10 in the 16 non-exposed), distribution of the localisations, morphology and importance of the cortical opacities. No link was found between the characteristics of the lens opacities and the characteristics of the exposure: habitual exposure and accidental overexposures. For cataracts, defined by the association of lens opacities and a visual acuity less than 20/25 (this loss not being attributable to another cause), their prevalence differed significantly (p less than 0.05) between the exposed (6 of 21) and the non-exposed (0 of 16). There was no relation between their existence and accidental overexposures. The risk of lens opacification by ethylene oxide, established in cases of massive exposures as previously described, could also exist during chronic exposure to low concentrations, but is to be confirmed by other studies. It could be explained by saturation of the protective mechanisms against alkylating action of this product. This study prompted us to discuss the epidemiological difficulties in studies of cataracts.

[Predicting Spectra of Accretion Disks Around Galactic Black Holes

NASA Technical Reports Server (NTRS)

Krolik, Julian H.

2004-01-01

The purpose of this grant was to construct detailed atmosphere solutions in order to predict the spectra of accretion disks around Galactic black holes. Our plan of action was to take an existing disk atmosphere code (TLUSTY, created by Ivan Hubeny) and introduce those additional physical processes necessary to make it applicable to disks of this variety. These modifications include: treating Comptonization; introducing continuous opacity due to heavy elements; incorporating line opacity due to heavy elements; adopting a disk structure that reflects readjustments due to radiation pressure effects; and injecting heat via a physically-plausible vertical distribution.

Research on Spectroscopy, Opacity, and Atmospheres

NASA Technical Reports Server (NTRS)

Oliversen, Ronald (Technical Monitor); Kurucz, Robert L.

2004-01-01

I propose to continue providing observers with basic data for interpreting spectra from stars, novas, supernovas, clusters, and galaxies. These data will include allowed forbidden line lists both laboratory and computed, for the first five to ten ions of all atoms and for all relevant diatomic molecules. I will eventually expend to all ions of the first thirty elements to treat far UV end X-ray spectra, and for envelope opacities. I also include triatomic molecules providing by other researchers. I have made CDs with Partridge and Schwanke's water data for work on M stars.The luna data also serve as input to my model atmosphere and synthesis programs that generated energy distributions, photometry, limb darkening, and spectra that can be used for planning observations and for fitting observed spectra. The spectrum synthesis programs produce detailed plots with the line identified. Grids of stellar spectra can be used for radial velocity-, rotation-, or abundance templates and for population synthesis. I am fitting spectra of bright stars to test the data and to produce atlases to guide observer. For each star the whole spectrum is computed from the UV to the far IR. The line data, opacities, models, spectra, and programs are freely distributed on CDs and on my web site and represent a unique resource for many NASA programs.

Thermal Structure and Dynamics of Saturn's Northern Springtime Disturbance

NASA Technical Reports Server (NTRS)

Fletcher, Leigh N.; Hesman, Brigette E.; Irwin, Patrick G.; Baines, Kevin H.; Momary, Thomas W.; SanchezLavega, Agustin; Flasar, F. Michael; Read, Peter L.; Orton, Glenn S.; SimonMiller, Amy;

Albedo of Carbon Dioxide Ice in Mars' Residual South Polar Cap

NASA Astrophysics Data System (ADS)

James, P. B.; Wolff, M. J.; Bonev, B.

2015-12-01

The albedo of surface CO2 deposits in the Residual South Polar Cap (RSPC) of Mars controls their net condensation / sublimation over a martian year and is therefore a crucial parameter in determining RSPC stability. The albedo used in previous analyses is obtained by dividing I/F, determined from radiometrically calibrated imaging data, by the cosine of the incidence angle. Because of atmospheric aerosols, the albedo calculated from I/F above the atmosphere is not the surface albedo that enters into stability considerations. In order to determine the surface albedo, we interpolate optical depths determined from CRISM EPF measurements to provide estimates of the dust and ice opacities over the RSPC (Wolff et al., 2009) and use these to determine the actual surface albedos from MARCI images using the radiative transport program DISORT (Stamnes et al., 1988). Assuming that dust is the only contributor to atmospheric opacity, the retrieved surface albedos for the longer wavelength MARCI filters in MY 28 and 29 are found to be consistent despite very different dust opacities in the two years (James et al., 2014). However, this model fails to reproduce the short wavelength behavior in early summer and suggests either an additional opacity source or modification of the CRISM dust opacity or the dust phase function. The consequences of these changes will be discussed.

Retrieval of ammonia abundances and cloud opacities on Jupiter from Voyager IRIS spectra

NASA Technical Reports Server (NTRS)

Conrath, B. J.; Gierasch, P. J.

1986-01-01

Gaseous ammonia abundances and cloud opacities are retrieved from Voyager IRIS 5- and 45-micron data on the basis of a simplified atmospheric model and a two-stream radiative transfer approximation, assuming a single cloud layer with 680-mbar base pressure and 0.14 gas scale height. Brightness temperature measurements obtained as a function of emission angle from selected planetary locations are used to verify the model and constrain a number of its parameters.

A Novel Technique to Calculate UV Opacity at Gale Crater from MSL/REMS Measurements

NASA Astrophysics Data System (ADS)

Vicente-Retortillo, Álvaro; Martínez, Germán M.; Renno, Nilton O.; Lemmon, Mark T.; Mason, Emily L.; de la Torre-Juárez, Manuel

2016-04-01

The Rover Environmental Monitoring Station (REMS) on board the Mars Science Laboratory (MSL) mission carries a UV sensor that for the first time is measuring the solar radiation at the surface of Mars in six bands between 200 and 380 nm [1]. Here we present a novel methodology to calculate the atmospheric opacity by using the UV photodiode output currents measured by this sensor (TELRDR products) and ancillary (ADR) data. We estimate the diffuse and total radiation signals by analyzing the events in which the direct solar beam was temporarily blocked by the masthead or by the mast of the rover. Then we use a radiative transfer model with updated radiative properties of the Martian aerosols ([2], [3]) based on the Monte-Carlo method to retrieve the UV opacity from those measurements. Therefore, this methodology is not sensitive to the degradation of the sensor due to the deposition of dust on it. In addition, by using TELRDR and ADR data, inconsistencies in the processed reduced data (ENVRDR and MODRDR products, in units of W/m2) found when the solar zenith angle relative to REMS rover frame is above 30° are avoided. In order to validate our technique, we compare the UV opacities with those derived from Mastcam observations at 880 nm. We find that both opacities show a good agreement and follow a similar seasonal trend, with the UV opacity showing values generally lower than at 880 nm. The difference between both opacities varies over the year, with the minimum difference occurring during the first half of the winter, when both opacities show their annual lowest values. The temporal variation of this difference may be used to analyze changes in the dust size distribution. [1] Gómez-Elvira, J., Armiens, C., Castañer, L., Domínguez, M., Genzer, M. et al. REMS: the environmental sensor suite for the Mars Science Laboratory rover. Space Sci. Rev., 170 (1-4), 583-640, 2012. [2] Vicente-Retortillo, A., Valero, F., Vázquez, L. and Martínez, G. M. A model to calculate solar radiation fluxes on the Martian surface. J. Space Weather Space Clim., 5, A33, 2015. [3] Wolff, M. J., Clancy, R. T., Goguen, J. D., Malin, M. C., and Cantor, B. A. Ultraviolet dust aerosol properties as observed by MARCI. Icarus, 208 (1), 143-155, 2010.

Consequences of a chromospheric temperature gradient on the width of H Alpha in late-type giants

NASA Technical Reports Server (NTRS)

Zarro, D. M.

1984-01-01

An analytic expression for the integrated H alpha optical depth profile is derived for a one dimensional slab geometry model chromosphere, with electron temperature increasing as a power law with height. The formula predicts H alpha opacity and profile width to be sensitive functions of the thermal gradient. Application of the model to observation reveals that broad H alpha absorption widths in G and K giant stars are consistent with a mean H alpha chromospheric optical depth of 50, while narrower widths in M stars indicate slightly lower opacities. It is proposed that differences in H alpha width between late-type giants of similar spectral type may be due, in part, to differences in their chromospheric thermal gradient, and associated H alpha opacity.

A non-grey analytical model for irradiated atmospheres. I. Derivation

NASA Astrophysics Data System (ADS)

Parmentier, Vivien; Guillot, Tristan

2014-02-01

Context. Semi-grey atmospheric models (with one opacity for the visible and one opacity for the infrared) are useful for understanding the global structure of irradiated atmospheres, their dynamics, and the interior structure and evolution of planets, brown dwarfs, and stars. When compared to direct numerical radiative transfer calculations for irradiated exoplanets, however, these models systematically overestimate the temperatures at low optical depths, independently of the opacity parameters. Aims: We investigate why semi-grey models fail at low optical depths and provide a more accurate approximation to the atmospheric structure by accounting for the variable opacity in the infrared. Methods: Using the Eddington approximation, we derive an analytical model to account for lines and/or bands in the infrared. Four parameters (instead of two for the semi-grey models) are used: a visible opacity (κv), two infrared opacities, (κ1 and κ2), and β (the fraction of the energy in the beam with opacities κ1). We consider that the atmosphere receives an incident irradiation in the visible with an effective temperature Tirr and at an angle μ∗, and that it is heated from below with an effective temperature Tint. Results: Our non-grey, irradiated line model is found to provide a range of temperatures that is consistent with that obtained by numerical calculations. We find that if the stellar flux is absorbed at optical depth larger than τlim = (κR/κ1κ2)(κRκP/3)1/2, it is mainly transported by the channel of lowest opacity whereas if it is absorbed at τ ≳ τlim it is mainly transported by the channel of highest opacity, independently of the spectral width of those channels. For low values of β (expected when lines are dominant), we find that the non-grey effects significantly cool the upper atmosphere. However, for β ≳ 1/2 (appropriate in the presence of bands with a wavelength-dependence smaller than or comparable to the width of the Planck function), we find that the temperature structure is affected down to infrared optical depths unity and deeper as a result of the so-called blanketing effect. Conclusions: The expressions that we derive can be used to provide a proper functional form for algorithms that invert the atmospheric properties from spectral information. Because a full atmospheric structure can be calculated directly, these expressions should be useful for simulations of the dynamics of these atmospheres and of the thermal evolution of the planets. Finally, they should be used to test full radiative transfer models and to improve their convergence. A FORTRAN implementation of the analytical model is available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/562/A133 Warning, no authors found for 2014A&A...562A.130.

Mars atmosphere studies with the SPICAM IR emission phase function observations

NASA Astrophysics Data System (ADS)

Trokhimovskiy, Alexander; Fedorova, Anna; Montmessin, Franck; Korablev, Oleg; Bertaux, Jean-Loup

Emission Phase Function (EPF) observations is a powerful tool for characterization of atmosphere and surface. EPF sequence provides the extensive coverage of scattering angles above the targeted surface location which allow to separate the surface and aerosol scattering, study a vertical distribution of minor species and aerosol properties. SPICAM IR instrument on Mars Express mission provides continuous atmospheric observations in near IR (1-1.7 mu) in nadir and limb starting from 2004. For the first years of SPICAM operation only a very limited number of EPFs was performed. But from the mid 2013 (Ls=225, MY31) SPICAM EPF observations become rather regular. Based on the multiple-scattering radiative transfer model SHDOM, we analyze equivalent depths of carbon dioxide (1,43 mu) and water vapour (1,38 mu) absorption bands and their dependence on airmass during observation sequence to get aerosol optical depths and properties. The derived seasonal dust opacities from near IR can be used to retrieve the size distribution from comparison with simultaneous results of other instruments in different spectral ranges. Moreover, the EPF observations of water vapour band allow to access poorly known H2O vertical distribution for different season and locations.

Density functional theory calculations of continuum lowering in strongly coupled plasmas.

PubMed

Vinko, S M; Ciricosta, O; Wark, J S

2014-03-24

An accurate description of the ionization potential depression of ions in plasmas due to their interaction with the environment is a fundamental problem in plasma physics, playing a key role in determining the ionization balance, charge state distribution, opacity and plasma equation of state. Here we present a method to study the structure and position of the continuum of highly ionized dense plasmas using finite-temperature density functional theory in combination with excited-state projector augmented-wave potentials. The method is applied to aluminium plasmas created by intense X-ray irradiation, and shows excellent agreement with recently obtained experimental results. We find that the continuum lowering for ions in dense plasmas at intermediate temperatures is larger than predicted by standard plasma models and explain this effect through the electronic structure of the valence states in these strong-coupling conditions.

Mars Dust and LETKF Data Assimilation of TES Observations

NASA Astrophysics Data System (ADS)

Greybush, S. J.; Hoffman, R. N.; Wilson, R.; Kang, J.; Zhao, Y.; Hoffman, M. J.; Kalnay, E.; Miyoshi, T.

2012-12-01

Simulation and prediction of dust storms remains one of the greatest challenges in Martian meteorology. Large-scale dust storms impact all Mars operations including spacecraft observations. What makes the difference between a regional event and a planet-encircling event? What are the predictability characteristics of these events and of the transition from regional to global? We examine the meteorology, including dustiness, in the Mars reanalysis created with the GFDL Mars Global Climate Model (MGCM) Local Ensemble Transform Kalman Filter (LETKF) data assimilation system (DAS). Characterizing the distribution and temporal evolution of dust in the Martian atmosphere is a considerable challenge. Spacecraft observations are sparse and have limitations in vertical coverage, dust physical properties are not well known, and model parameterizations of surface lifting have limited success in reproducing observed variability. Methods for generating a dust reanalysis begin with satellite inferred dust information in the form of column opacities, dust profile retrievals, or the original radiances. Opacities may be estimated from a formal retrieval of the satellite data or inferred through surface brightness temperatures. The opacities have been ingested via ad hoc adjustments to model tracer fields (Conrath vertical distributions, changes to the boundary layer dust only, etc.), but could also be assimilated by the LETKF or other advanced DAS. We will present dust distributions in the most recent version of the MGCM-LETKF Mars reanalysis. Current results are from two DASs, one assuming a fixed dust distribution and one using TES opacities and updating the boundary layer dust only. In these reanalyses, a full year of Thermal Emission Spectrometer (TES) temperature profiles have been assimilated. Since an accurate characterization of the sources and sinks of dust would greatly improve our understanding of the Martian dust cycle and its representation in numerical weather prediction models, we will examine two advanced DAS techniques that have been demonstrated in terrestrial DASs and could be applied to the problem -- surface dust flux estimation and estimating the surface parameters that control the source of dust (roughness, inventories). The surface dust flux method requires no a priori information about the fluxes, and uses only atmospheric observations. For the terrestrial CO2 problem, surface sources and sinks of CO2 have been estimated using only time-dependent measurements of atmospheric CO2, temperatures, and winds, and without a priori information on the surface fluxes. This scenario is very analogous to the case of Mars. On Mars we have only information on temperature and dust opacities at spacecraft overpass locations. Results for terrestrial CO2 and plans for Mars dust will be presented. However, to improve model parameterizations of dust lifting, we need to understand not only the planetary distribution of dust but also the evolution of its sources and sinks and their relation to meteorology. The surface parameters method assumes the physical properties have a persistence or damped persistence evolution equation. These are then treated as part of the model state vector in the LETKF. This approach is then analogous to the bias correction method used in LETKF to improve the atmospheric state estimation.

Optical properties of highly compressed polystyrene: An ab initio study

NASA Astrophysics Data System (ADS)

Hu, S. X.; Collins, L. A.; Colgan, J. P.; Goncharov, V. N.; Kilcrease, D. P.

2017-10-01

Using all-electron density functional theory, we have performed an ab initio study on x-ray absorption spectra of highly compressed polystyrene (CH). We found that the K -edge shifts in strongly coupled, degenerate polystyrene cannot be explained by existing continuum-lowering models adopted in traditional plasma physics. To gain insights into the K -edge shift in warm, dense CH, we have developed a model designated as "single mixture in a box" (SMIAB), which incorporates both the lowering of the continuum and the rising of the Fermi surface resulting from high compression. This simple SMIAB model correctly predicts the K -edge shift of carbon in highly compressed CH in good agreement with results from quantum molecular dynamics (QMD) calculations. Traditional opacity models failed to give the proper K -edge shifts as the CH density increased. Based on QMD calculations, we have established a first-principles opacity table (FPOT) for CH in a wide range of densities and temperatures [ρ =0.1 -100 g /c m3 and T =2000 -1 000 000 K ]. The FPOT gives much higher Rosseland mean opacity compared to the cold-opacity-patched astrophysics opacity table for warm, dense CH and favorably compares to the newly improved Los Alamos atomic model for moderately compressed CH (ρCH≤10 g /c m3 ), but remains a factor of 2 to 3 higher at extremely high densities (ρCH≥50 g /c m3 ). We anticipate the established FPOT of CH will find important applications to reliable designs of high-energy-density experiments. Moreover, the understanding of K -edge shifting revealed in this study could provide guides for improving the traditional opacity models to properly handle the strongly coupled and degenerate conditions.

Improvement of chronic corneal opacity in ocular surface disease with prosthetic replacement of the ocular surface ecosystem (PROSE) treatment.

PubMed

Cressey, Anna; Jacobs, Deborah S; Remington, Crystal; Carrasquillo, Karen G

2018-06-01

To demonstrate clearing of chronic corneal opacities and improvement of visual acuity with the use of BostonSight prosthetic replacement of the ocular surface ecosystem (PROSE) treatment in ocular surface disease. We undertook retrospective analysis of the medical records of a series of patients who underwent PROSE treatment from August 2006 to December 2014. Patients were referred for ocular surface disease of various etiologies. Primary inclusion criterion was corneal opacity that improved with PROSE treatment. Patients were excluded if topical steroids or adjuvant therapy used once PROSE treatment was initiated. Underlying disease, prior treatment, clinical presentation, and clinical course were extracted from the medical record. Four patients are included in this series. There were three females and one male; median age at time of treatment initiation was 30 years (range = 0.5-58 years). Median duration of PROSE treatment at time of retrospective analysis was 3.5 years (range = 1-8 years). Two cases had corneal opacification in the context of neurotrophic keratopathy: a unilateral case due to presumed herpes simplex keratitis and a bilateral case due to congenital corneal anesthesia associated with familial dysautonomia. One case had corneal opacity from exposure related to seventh nerve palsy, and one had corneal opacification associated with recurrent surface breakdown, neurotrophic keratopathy, and limbal stem deficiency of uncertain etiology. After consistent wear of prosthetic devices used in PROSE treatment for support of the ocular surface, visual acuity improved and clearing of the opacities was observed, without use of topical steroids or adjuvant therapy. These cases demonstrate clearing of chronic corneal opacity with PROSE treatment for ocular surface disease. This clearing can occur with no adjuvant therapy, suggesting that restoration of ocular surface function and integrity allows for corneal remodeling.

Analysis of clinical value of CT in the diagnosis of pediatric pneumonia and mycoplasma pneumonia.

PubMed

Gong, Liang; Zhang, Chong-Lin; Zhen, Qing

2016-04-01

Pneumonia is an infectious disease of the lung causing mortality. Mycoplasma pneumonia (MP) is an atypical bacterial pneumonia that damages several organs. Lung computed tomography (CT) has been utilized in its identification. The aim of the present study was to examine the value of computed tomography diagnosis for pediatric MP. The present study prospectively analyzed the clinical and imaging data of 1,280 cases of pediatric MP in the out- and inpatient departments from March, 2010 to March, 2014; analyzed the morphology and distribution of the pneumonic lesion in the lungs; and summarized the value of CT diagnosis for pediatric MP. In the included children, there were 688 cases of lesions in the unilateral lobe, 592 cases of lesions in the bilateral lobes, 1,101 cases of extensive patchy opacity, 496 cases of mottled opacity, 432 cases of increased lung marking, 256 cases of streak opacity, 192 cases of ground-glass opacity, 992 cases of thickened bronchial wall in the lesions, 128 cases of lymphadenopathy in the hilar lymph nodes and mediastinal lymph nodes, and the lung CT showed 32 cases of pulmonary cavity and 144 cases of pleural effusion. In conclusion, the CT signals of pediatric MP had several types with some children exhibiting complicated changes. The child's clinical manifestation and symptoms should thus be considered in the diagnosis to improve the diagnostic rate.

Dust Coagulation in Protoplanetary Accretion Disks

NASA Technical Reports Server (NTRS)

Schmitt, W.; Henning, Th.; Mucha, R.

1996-01-01

The time evolution of dust particles in circumstellar disk-like structures around protostars and young stellar objects is discussed. In particular, we consider the coagulation of grains due to collisional aggregation. The coagulation of the particles is calculated by solving numerically the non-linear Smoluchowski equation. The different physical processes leading to relative velocities between the grains are investigated. The relative velocities may be induced by Brownian motion, turbulence and drift motion. Starting from different regimes which can be identified during the grain growth we also discuss the evolution of dust opacities. These opacities are important for both the derivation of the circumstellar dust mass from submillimeter/millimeter continuum observations and the dynamical behavior of the disks. We present results of our numerical studies of the coagulation of dust grains in a turbulent protoplanetary accretion disk described by a time-dependent one-dimensional (radial) alpha-model. For several periods and disk radii, mass distributions of coagulated grains have been calculated. From these mass spectra, we determined the corresponding Rosseland mean dust opacities. The influence of grain opacity changes due to dust coagulation on the dynamical evolution of a protostellar disk is considered. Significant changes in the thermal structure of the protoplanetary nebula are observed. A 'gap' in the accretion disk forms at the very frontier of the coagulation, i.e., behind the sublimation boundary in the region between 1 and 5 AU.

Saturn's Regional and Global Cloud Properties from Cassini/VIMS 4.5-5.1 Micron Spectroscopy

NASA Astrophysics Data System (ADS)

Fletcher, Leigh N.; Baines, K. H.; Momary, T. W.; Orton, G. S.; Roos-Serote, M.; Irwin, P. G. J.

2009-09-01

Exploiting a region of Saturn's thermal-IR spectrum between 4.5-5.1 microns where there is a dearth of opacity sources, Cassini/VIMS has revealed a wealth of dynamical phenomena in the 1-4 bar region that are transforming our understanding of the gas giant. Narrow dark lanes and discrete cloud features are observed in silhouette against the 5-micron background thermal glow of Saturn's deep atmosphere. The NEMESIS optimal-estimation retrieval algorithm (Irwin et al., JSQRT, 2008) is used to model the 4.5-5.1 micron region using the correlated-k approximation. We determine (a) the sensitivity and correlations associated with determinations of cloud properties and gaseous composition from the Cassini/VIMS dataset; (b) the meridional variation in opacity sources (a multi-layer cloud model, the abundances of phosphine and arsine); (c) the contribution of the thermal and reflected components to VIMS spectra and (d) the spatial variability of opacity sources associated with Saturn's string of pearls and ribbon wave features in the northern hemisphere. The meridional gradients in composition are compared to the Cassini/CIRS derivations of phosphine at higher altitudes (pressures less than 1 bar; Fletcher et al., Icarus, 2009). The seasonal origin of the north-south asymmetry in 5-micron opacity (Baines et al., BAAS, 2006) and the dynamical motions associated with Saturn's complex zonal wave activity will be discussed. The vertical distribution of cloud opacity demonstrates the necessity for aerosols at the 2-3 bar level to successfully replicate the VIMS data. Finally, we search Cassini/CIRS mapping observations at 15.0 cm-1 resolution for mid-IR counterparts (0.1-0.5 bar) to the zonal wave activity in the deeper troposphere (1-4 bars) to investigate the vertical coupling in Saturn's troposphere.

Monitoring temporal opacity fluctuations of large structures with muon radiography: a calibration experiment using a water tower

PubMed Central

Jourde, Kevin; Gibert, Dominique; Marteau, Jacques; de Bremond d’Ars, Jean; Gardien, Serge; Girerd, Claude; Ianigro, Jean-Christophe

2016-01-01

Usage of secondary cosmic muons to image the geological structures density distribution significantly developed during the past ten years. Recent applications demonstrate the method interest to monitor magma ascent and volcanic gas movements inside volcanoes. Muon radiography could be used to monitor density variations in aquifers and the critical zone in the near surface. However, the time resolution achievable by muon radiography monitoring remains poorly studied. It is biased by fluctuation sources exterior to the target, and statistically affected by the limited number of particles detected during the experiment. The present study documents these two issues within a simple and well constrained experimental context: a water tower. We use the data to discuss the influence of atmospheric variability that perturbs the signal, and propose correction formulas to extract the muon flux variations related to the water level changes. Statistical developments establish the feasibility domain of muon radiography monitoring as a function of target thickness (i.e. opacity). Objects with a thickness comprised between ≈50 ± 30 m water equivalent correspond to the best time resolution. Thinner objects have a degraded time resolution that strongly depends on the zenith angle, whereas thicker objects (like volcanoes) time resolution does not. PMID:26971718

Risk Factors for Cortical, Nuclear, Posterior Subcapsular, and Mixed Lens Opacities: The Los Angeles Latino Eye Study

PubMed Central

Richter, Grace M.; Torres, Mina; Choudhury, Farzana; Azen, Stanley P.; Varma, Rohit

2012-01-01

Purpose To identify socio-demographic and biological risk factors associated with having cortical, nuclear, posterior sub-capsular (PSC), and mixed lens opacities. Design Population-based, cross-sectional study Participants Five thousand nine hundred forty-five Latinos 40 years and older from 6 census tracts in Los Angeles, California. Methods Participants underwent an interview and detailed eye examination, including best-corrected visual acuity and slit-lamp assessment of lens opacities using the Lens Opacities Classification System II. Univariate and stepwise logistic regression analyses were used to identify independent risk factors associated with each type of lens opacity. Main Outcome Measures Odds ratios for socio-demographic and biological risk factors associated with cortical only, nuclear only, PSC only, and mixed lens opacities. Results Of the 5945 participants with gradable lenses, 468 had cortical only lens opacities, 217 had nuclear only lens opacities, 27 had PSC only opacities, and 364 had mixed lens opacities. Older age, higher hemoglobin A1c, and history of diabetes mellitus were independent risk factors for cortical only lens opacities. Older age, smoking, and myopic refractive error were independent risk factors for nuclear only lens opacities. Higher systolic blood pressure and history of diabetes were independent risk factors for posterior sub-capsular lens opacities. Older age, myopic refractive error, history of diabetes, higher systolic blood pressure, female gender, and presence of large drusen were independent risk factors for mixed lens opacities. Conclusions The modifiable and non-modifiable risk factors identified in this study provide insight into the mechanisms related to the development of lens opacification. Improved glycemic control, smoking cessation and prevention, and blood pressure control may help to reduce the risk of having lens opacities and their associated vision loss. PMID:22197433

Temporal and spatial mapping of atmospheric dust opacity and surface albedo on Mars

NASA Technical Reports Server (NTRS)

Lee, S. W.; Clancy, R. T.; Gladstone, G. R.; Martin, T. Z.

1993-01-01

The Mariner 9 and Viking missions provided abundant evidence that eolian processes are active over much of the surface of Mars. Past studies have demonstrated that variations in regional albedo and wind streak patterns are indicative of sediment transport through a region, while thermal inertia data (derived from the Viking Infrared Thermal Mapper (IRTM) datasets) are indicative of the degree of surface mantling by dust deposits. We are making use of the method developed by T. Z. Martin to determine dust opacity from IRTM thermal observations. We have developed a radiative transfer model that allows corrections for the effects of atmospheric dust loading on observations of surface albedo to be made. This approach to determining 'dust-corrected surface albedo' incorporates the atmospheric dust opacity, the single-scattering albedo and particle phase function of atmospheric dust, the bidirectional reflectance of the surface, and accounts for variable lighting and viewing geometry.

Modeling Broadband X-Ray Absorption of Massive Star Winds

NASA Technical Reports Server (NTRS)

Leutenegger, Maurice A.; Cohen,David H.; Zsargo, Janos; Martell, Erin M.; MacArthur, James P.; Owocki, Stanley P.; Gagne, Marc; Hillier, D. John

2010-01-01

We present a method for computing the net transition of X-rays emitted by shock-heated plasma distributed throughout a partially optically thick stellar wind from a massive star. We find the transmission by an exact integration of the formal solution, assuming the emitting plasma and absorbing plasma are mixed at a constant mass ratio above some minimum radius, below which there is assumed to be no emission. This model is more realistic than either the slab absorption associated with a corona at the base of the wind or the exospheric approximation that assumes all observed X-rays are emitted without attenuation from above the radius of optical depth unity. Our model is implemented in XSPEC as a pre-calculated table that can be coupled to a user-defined table of the wavelength dependent wind opacity. We provide a default wind opacity model that is more representative of real wind opacities than the commonly used neutral ISM tabulation. Preliminary modeling of Chandra grating data indicates that the X-ray hardness trend of OB stars with spectral subtype cars largely be understood as a wind absorption effect.

Multilevel Analysis of Trachomatous Trichiasis and Corneal Opacity in Nigeria: The Role of Environmental and Climatic Risk Factors on the Distribution of Disease.

PubMed

Smith, Jennifer L; Sivasubramaniam, Selvaraj; Rabiu, Mansur M; Kyari, Fatima; Solomon, Anthony W; Gilbert, Clare

2015-01-01

The distribution of trachoma in Nigeria is spatially heterogeneous, with large-scale trends observed across the country and more local variation within areas. Relative contributions of individual and cluster-level risk factors to the geographic distribution of disease remain largely unknown. The primary aim of this analysis is to assess the relationship between climatic factors and trachomatous trichiasis (TT) and/or corneal opacity (CO) due to trachoma in Nigeria, while accounting for the effects of individual risk factors and spatial correlation. In addition, we explore the relative importance of variation in the risk of trichiasis and/or corneal opacity (TT/CO) at different levels. Data from the 2007 National Blindness and Visual Impairment Survey were used for this analysis, which included a nationally representative sample of adults aged 40 years and above. Complete data were available from 304 clusters selected using a multi-stage stratified cluster-random sampling strategy. All participants (13,543 individuals) were interviewed and examined by an ophthalmologist for the presence or absence of TT and CO. In addition to field-collected data, remotely sensed climatic data were extracted for each cluster and used to fit Bayesian hierarchical logistic models to disease outcome. The risk of TT/CO was associated with factors at both the individual and cluster levels, with approximately 14% of the total variation attributed to the cluster level. Beyond established individual risk factors (age, gender and occupation), there was strong evidence that environmental/climatic factors at the cluster-level (lower precipitation, higher land surface temperature, higher mean annual temperature and rural classification) were also associated with a greater risk of TT/CO. This study establishes the importance of large-scale risk factors in the geographical distribution of TT/CO in Nigeria, supporting anecdotal evidence that environmental conditions are associated with increased risk in this context and highlighting their potential use in improving estimates of disease burden at large scales.

Dust in AGB Stars: Transparent or Opaque?

NASA Astrophysics Data System (ADS)

Bladh, S.; Höfner, S.; Aringer, B.

2011-09-01

The optical properties of the dust particles that drive the winds of cool giant stars affect the stellar spectra in two ways: (1) indirectly, through their influence on the dynamical structure of the atmosphere/envelope and the resulting molecular features, and (2) directly, by changes of the spectral energy distribution due to absorption and scattering on dust grains. The qualitative differences in the energy distributions of C-type and M-type AGB stars in the visual and near-infrared regions suggest that the dust particles in oxygen rich atmospheres are relatively transparent to radiation. By using detailed dynamical models of gas and radiation combined with a simple description for the dust opacity (which can be adjusted to mimic different wavelength dependences and condensation temperatures) and also by adjusting the fraction of the opacity that is treated as true absorption, we investigate which dust properties produce synthetic photometry consistent with observations. The goal of this study is to narrow down the possible dust species that may be driving the winds in M-type AGB stars.

Silicosis Appears Inevitable Among Former Denim Sandblasters: A 4-Year Follow-up Study.

PubMed

Akgun, Metin; Araz, Omer; Ucar, Elif Yilmazel; Karaman, Adem; Alper, Fatih; Gorguner, Metin; Kreiss, Kathleen

2015-09-01

The course of denim sandblasting silicosis is unknown. We aimed to reevaluate former sandblasters studied in 2007 for incident silicosis, radiographic progression, pulmonary function loss, and mortality and to examine any associations between these outcomes and previously demonstrated risk factors for silicosis. We defined silicosis on chest radiograph as category 1/0 small opacity profusion using the International Labor Organization classification. We defined radiographic progression as a profusion increase of two or more subcategories, development of a new large opacity, or an increase in large opacity category. We defined pulmonary function loss as a ≥ 12% decrease in FVC. Among the 145 former sandblasters studied in 2007, 83 were reassessed in 2011. In the 4-year follow-up period, nine (6.2%) had died at a mean age of 24 years. Of the 74 living sandblasters available for reexamination, the prevalence of silicosis increased from 55.4% to 95.9%. Radiographic progression, observed in 82%, was associated with younger age, never smoking, foreman work, and sleeping at the workplace. Pulmonary function loss, seen in 66%, was positively associated with never smoking and higher initial FVC % predicted. Death was associated with never smoking, foreman work, number of different denim-sandblasting places of work, sleeping at the workplace, and lower pulmonary function, of which only the number of different places worked remained in multivariate analyses. This 4-year follow-up suggests that almost all former denim sandblasters may develop silicosis, despite short exposures and latency.

Radiative opacities of iron using a difference algebraic converging method at temperatures near solar convection zone

NASA Astrophysics Data System (ADS)

Fan, Zhixiang; Sun, Weiguo; Zhang, Yi; Fu, Jia; Hu, Shide; Fan, Qunchao

2018-03-01

An interpolation method named difference algebraic converging method for opacity (DACMo) is proposed to study the opacities and transmissions of metal plasmas. The studies on iron plasmas at temperatures near the solar convection zone show that (1) the DACMo values reproduce most spectral structures and magnitudes of experimental opacities and transmissions. (2) The DACMo can be used to predict unknown opacities at other temperature Te' and density ρ' using the opacity constants obtained at ( Te , ρ). (3) The DACMo may predict reasonable opacities which may not be available experimentally but the least-squares (LS) method does not. (4) The computational speed of the DACMo is at least 10 times faster than that of the original difference converging method for opacity.

Dust lifting in GEM-Mars using a roughness length map

NASA Astrophysics Data System (ADS)

Daerden, F.; Neary, L.; Whiteway, J. A.; Hébrard, E.

2013-09-01

Lifting of size distributed dust due to surface wind stress and dust devils has been implemented in the GEM-Mars 3D-GCM. It turned out that a detailed surface roughness length map was necessary to bring the simulated dust opacities in accordance with observations.

Mars atmospheric opacity effects observed in the Northern Hemisphere by Viking orbiter imaging

NASA Technical Reports Server (NTRS)

Thorpe, T. E.

1981-01-01

Viking orbiter television camera observations of Mars contrasts show variations of atmospheric opacity in the Southern Hemisphere. The study is extended into the Northern Hemisphere, over a longer time period, and results in a detailed description of photometric changes at the lander sites, as seen from orbit. During the period of January 1977 to April 1978, a series of four storms at 202 deg, 264 deg, 40 deg and 86 deg latitudes have provided photometric changes and planetwide aerosol distributions for 18 months. It is found that the large, forward-scattering particles did not enter the atmosphere at the storm's onsets. A reduction of atmospheric transmission by over 20% at visual wavelengths remained for nearly one Martian year.

Three-dimensional microscopic tomographic imagings of the cataract in a human lens in vivo

NASA Astrophysics Data System (ADS)

Masters, Barry R.

1998-10-01

The problem of three-dimensional visualization of a human lens in vivo has been solved by a technique of volume rendering a transformed series of 60 rotated Scheimpflug (a dual slit reflected light microscope) digital images. The data set was obtained by rotating the Scheimpflug camera about the optic axis of the lens in 3 degree increments. The transformed set of optical sections were first aligned to correct for small eye movements, and then rendered into a volume reconstruction with volume rendering computer graphics techniques. To help visualize the distribution of lens opacities (cataracts) in the living, human lens the intensity of light scattering was pseudocolor coded and the cataract opacities were displayed as a movie.

Thermal Emission Spectrometer Results: Mars Atmospheric Thermal Structure and Aerosol Distribution

NASA Technical Reports Server (NTRS)

Smith, Michael D.; Pearl, John C.; Conrath, Barney J.; Christensen, Philip R.; Vondrak, Richard R. (Technical Monitor)

2001-01-01

Infrared spectra returned by the Thermal Emission Spectrometer (TES) are well suited for retrieval of the thermal structure and the distribution of aerosols in the Martian atmosphere. Combined nadir- and limb-viewing spectra allow global monitoring of the atmosphere up to 0.01 mbar (65 km). We report here on the atmospheric thermal structure and the distribution of aerosols as observed thus far during the mapping phase of the Mars Global Surveyor mission. Zonal and temporal mean cross sections are used to examine the seasonal evolution of atmospheric temperatures and zonal winds during a period extending from northern hemisphere mid-summer through vernal equinox (L(sub s) = 104-360 deg). Temperature maps at selected pressure levels provide a characterization of planetary-scale waves. Retrieved atmospheric infrared dust opacity maps show the formation and evolution of regional dust storms during southern hemisphere summer. Response of the atmospheric thermal structure to the changing dust loading is observed. Maps of water-ice clouds as viewed in the thermal infrared are presented along with seasonal trends of infrared water-ice opacity. Uses of these observations for diagnostic studies of the dynamics of the atmosphere are discussed.

40 CFR 60.1760 - What is required for my continuous opacity monitoring system and how are the data used?

Code of Federal Regulations, 2011 CFR

2011-07-01

... opacity monitoring system and how are the data used? 60.1760 Section 60.1760 Protection of Environment... continuous opacity monitoring system and how are the data used? (a) Install, calibrate, maintain, and operate a continuous opacity monitoring system. (b) Install, evaluate, and operate each continuous opacity...

VizieR Online Data Catalog: Analytical model for irradiated atmospheres (Parmentier+, 2015)

NASA Astrophysics Data System (ADS)

Parmentier, V.; Guillot, T.; Fortney, J.; Marley, M.

2014-11-01

The model has six parameters to describe the opacities: - {kappa}(N) is the Rosseland mean opacity at each levels of the atmosphere it does not have to be constant with depth. - Gp is the ratio of the thermal Plank mean opacity to the thermal Rosseland mean opacity. - Beta is the width ratio of the two thermal bands in the frequency space. - Gv1 is the ratio of the visible opacity in the first visible band to the thermal Rosseland mean opacity - Gv2 is the ratio of the visible opacity in the second visible band to the thermal Rosseland mean opacity - Gv3 is the ratio of the visible opacity in the second visible band to the thermal Rosseland mean opacity Each visible band has a fixed width of 1/3. Additional parameters describe the physical setting: - Teq0 is the equilibrium temperature of the planet for 0 albedo and full redistribution of energy. - mu is the angle between the vertical direction and the stellar direction. For average profiles set mu=1/sqrt(3) - f is a parameter equal to 0.5 to compute a dayside average profile and 0.25 for planet average profile. - Tint is the internal temperature, given by the internal luminosity - grav is the gravity of the planet - Ab is the Bond albedo of the planet - P(i) are the pressure levels where the temperature is computed. - N is the number of atmospheric levels. Several options are available in order to use the coefficients derived in Parmentier et al. (2014A&A...562A.133P, Cat. J/A+A/562/A133): ROSS can take the values : - "USER" for a Rosseland mean opacity set by the user {kappa}(nlevels) through the atmosphere. - "AUTO" in order to use {kappa}(P,T), the functional form of the Rosseland mean opacities provided by Valencia et al. (2013ApJ...775...10V) and based on the opacities calculated by Freedman et al. (2008ApJS..174..504F). The value of {kappa} is then recalculated and the initial value set by the user is NOT taken into account. COEFF can take the values : - "USER" for coefficients set by the user - "AUTO" for using the fit of the coefficients provided in Parmentier et al. (2014A&A...562A.133P, Cat. J/A+A/562/A133). In that case all the coefficients set by the user are NOT taken into account (apart for the Rosseland mean opacities) COMP can take the values (Valid only if COEFF="AUTO") : - "SOLAR" to use the fit of the coefficients for a solar composition atmosphere - "NOTIO" to use the fit of the coefficients without TiO STAR can take the value (Valid only if COEFF="AUTO"): - "SUN" to use the fit of the coefficients for a sun-like stellar irradiation ALBEDO can thake the value : - "USER" for a user defined albedo - "AUTO" to use the fit of the albedos for solar-composition, clear-sky atmospheres CONV can be either : - "NO" for a pure radiative solution - "YES" for a radiative/convective solution (without taking into account detached convective layers) The code and all the outputs uses SI units. Installation and use : to install the code use the command "make". To test use "make test". The test should be done with the downloaded version of the code, without any changes. To execute the code, once it has been compiled, type ./NonGrey in the same directory.This will output a file PTprofile.csv with the temperature structure in csv format and a file PTprofile.dat in dat format. The input parameters must be changed inside the file paper2.f90. It is necessary to compile the code again each time. The subroutine tprofile2e.f90 can be directly implemented into one's code. (5 data files).

Dust Aerosol Particle Size at the Mars Science Laboratory Landing Site

NASA Astrophysics Data System (ADS)

Vicente-Retortillo, Alvaro; Martínez, Germán; Renno, Nilton; Lemmon, Mark; de la Torre-Juárez, Manuel

2017-04-01

We have developed a new methodology to retrieve dust aerosol particle size from Mars Science Laboratory (MSL) observations [1]. We use photodiode output currents measured by the Rover Environmental Monitoring Station (REMS) UV sensor (UVS), ancillary data records (ADR) containing the geometry of the rover and the Sun, and values of the atmospheric opacity retrieved from Mastcam measurements. In particular, we analyze REMS UVS measurements when the Sun is blocked by the masthead and the mast of the rover since the behavior of the output currents during these shadow events depends on the dust phase function, which depends on particle size. The retrieved dust effective radii show a significant seasonal variability, ranging from 0.6 μm during the low opacity season (Ls = 60° - 140°) to 2 μm during the high opacity season (Ls = 180° - 360°). The relationship between atmospheric opacity and dust particle size indicates that dust-lifting events originate at various distances from Gale Crater. The external origin of high dust content events is consistent with the strong and persistent northerly and northwesterly winds at Gale Crater during the perihelion season centered around Ls = 270° [2]. From an interannual perspective, the general behavior of the particle size evolution in MY 31-32 is similar to that in MY 32-33, although some differences are noted. During the low opacity season (Ls = 60° - 140°), the retrieved dust effective radii in MY 33 are significantly lower than in MY 32. A larger contribution of water ice clouds to the total atmospheric opacity during the aphelion season of MY 33 can partially explain such a departure. Differences during the perihelion season are caused by interannual variability of enhanced opacity events. The determination of dust aerosol particle size is important to improve the accuracy of models in simulating the UV environment at the surface [3] and in predicting heating rates, which affect the atmospheric thermal and dynamical fields, and aerosol atmospheric transport, including gravitational settling rates. References: [1] Vicente-Retortillo, A. et al., GRL, submitted. [2] Rafkin, S. et al. (2016), Icarus, 280, 114-138. [3] Webster, C.R., et al. (2016), AGU Fall Meeting.

Thermal Cyclotron Absorption Coefficients. II. Opacities in the Stokes Formalism

NASA Astrophysics Data System (ADS)

Vaeth, H. M.; Chanmugam, G.

1995-05-01

We extend the discussion of the calculation of the cyclotron opacities α± of the ordinary and extraordinary mode (Chanmugam et al.) to the opacities κ, q, υ in the Stokes formalism. We derive formulae with which a can be calculated from κ, q, υ. We are hence able to compare our calculations of the opacities, which are based on the single-particle method, with results obtained with the dielectric tensor method of Tam or. Excellent agreement is achieved. We present extensive tables of the opacities in the Stokes formalism for frequencies up to 25ωc, where ωc is the cyclotron frequency, and temperatures kT = 5, 10,20, 30,40, and 50 keV. Furthermore, we derive approximate formulae with which κ, q, υ can be calculated from α± and hence use the Robinson & Melrose analytic formulae for α± in order to calculate the opacities in the Stokes formalism. We compare these opacities to accurate numerical opacities and find that the analytic formulae can reproduce the qualitative behavior of the opacities in the regions where the harmonic structure is unimportant.

An improved random walk algorithm for the implicit Monte Carlo method

DOE Office of Scientific and Technical Information (OSTI.GOV)

Keady, Kendra P., E-mail: keadyk@lanl.gov; Cleveland, Mathew A.

In this work, we introduce a modified Implicit Monte Carlo (IMC) Random Walk (RW) algorithm, which increases simulation efficiency for multigroup radiative transfer problems with strongly frequency-dependent opacities. To date, the RW method has only been implemented in “fully-gray” form; that is, the multigroup IMC opacities are group-collapsed over the full frequency domain of the problem to obtain a gray diffusion problem for RW. This formulation works well for problems with large spatial cells and/or opacities that are weakly dependent on frequency; however, the efficiency of the RW method degrades when the spatial cells are thin or the opacities aremore » a strong function of frequency. To address this inefficiency, we introduce a RW frequency group cutoff in each spatial cell, which divides the frequency domain into optically thick and optically thin components. In the modified algorithm, opacities for the RW diffusion problem are obtained by group-collapsing IMC opacities below the frequency group cutoff. Particles with frequencies above the cutoff are transported via standard IMC, while particles below the cutoff are eligible for RW. This greatly increases the total number of RW steps taken per IMC time-step, which in turn improves the efficiency of the simulation. We refer to this new method as Partially-Gray Random Walk (PGRW). We present numerical results for several multigroup radiative transfer problems, which show that the PGRW method is significantly more efficient than standard RW for several problems of interest. In general, PGRW decreases runtimes by a factor of ∼2–4 compared to standard RW, and a factor of ∼3–6 compared to standard IMC. While PGRW is slower than frequency-dependent Discrete Diffusion Monte Carlo (DDMC), it is also easier to adapt to unstructured meshes and can be used in spatial cells where DDMC is not applicable. This suggests that it may be optimal to employ both DDMC and PGRW in a single simulation.« less

Polarization simulations of stellar wind bow-shock nebulae - I. The case of electron scattering

NASA Astrophysics Data System (ADS)

Shrestha, Manisha; Neilson, Hilding R.; Hoffman, Jennifer L.; Ignace, Richard

2018-06-01

Bow shocks and related density enhancements produced by the winds of massive stars moving through the interstellar medium provide important information regarding the motions of the stars, the properties of their stellar winds, and the characteristics of the local medium. Since bow-shock nebulae are aspherical structures, light scattering within them produces a net polarization signal even if the region is spatially unresolved. Scattering opacity arising from free electrons and dust leads to a distribution of polarized intensity across the bow-shock structure. That polarization encodes information about the shape, composition, opacity, density, and ionization state of the material within the structure. In this paper, we use the Monte Carlo radiative transfer code SLIP to investigate the polarization created when photons scatter in a bow-shock-shaped region of enhanced density surrounding a stellar source. We present results for electron scattering, and investigate the polarization behaviour as a function of optical depth, temperature, and source of photons for two different cases: pure scattering and scattering with absorption. In both regimes, we consider resolved and unresolved cases. We discuss the implications of these results as well as their possible use along with observational data to constrain the properties of observed bow-shock systems. In different situations and under certain assumptions, our simulations can constrain viewing angle, optical depth and temperature of the scattering region, and the relative luminosities of the star and shock.

Water Ice Cloud Opacities and Temperatures Derived from the Viking IRTM Data Set

NASA Technical Reports Server (NTRS)

TamppariL. K.; Zurek, R. W.; Paige, D. A.

1999-01-01

The degree to which water ice clouds play a role in the Mars climate is unknown. Latent heating of water ice clouds is small and since most hazes appeared to be thin (tau less than or = 1) their radiative effects have been neglected. Condensation likely limits the vertical extent of water vapor in the water column and a lowering of the condensation altitude, as seen in the northern spring and summer, could increase the seasonal exchange of water between the atmosphere and the surface. It has been suggested that water ice cloud formation is more frequent and widespread in the aphelic hemisphere (currently the northern). This may limit water to the northern hemisphere through greater exchange with the regolith and through restricted southward transport of water vapor by the Mars Hadley circulation. In addition, it has been suggested that water ice cloud formation also controls the vertical distribution of atmospheric dust in some seasons. This scavenging of dust may Continuing from the IRTM cloud maps, derived cloud opacities and cloud temperatures for several locations and seasons will be presented. Sensitivities to cloud particle sizes, surface temperature, and dust opacity will be discussed.

Phonology without universal grammar

PubMed Central

Archangeli, Diana; Pulleyblank, Douglas

2015-01-01

The question of identifying the properties of language that are specific human linguistic abilities, i.e., Universal Grammar, lies at the center of linguistic research. This paper argues for a largely Emergent Grammar in phonology, taking as the starting point that memory, categorization, attention to frequency, and the creation of symbolic systems are all nonlinguistic characteristics of the human mind. The articulation patterns of American English rhotics illustrate categorization and systems; the distribution of vowels in Bantu vowel harmony uses frequencies of particular sequences to argue against Universal Grammar and in favor of Emergent Grammar; prefix allomorphy in Esimbi illustrates the Emergent symbolic system integrating phonological and morphological generalizations. The Esimbi case has been treated as an example of phonological opacity in a Universal Grammar account; the Emergent analysis resolves the pattern without opacity concerns. PMID:26388791

Formation of Planetary Populations I: Metallicity & Envelope Opacity Effects

NASA Astrophysics Data System (ADS)

Alessi, Matthew; Pudritz, Ralph E.

2018-05-01

We present a comprehensive body of simulations of the formation of exoplanetary populations that incorporate the role of planet traps in slowing planetary migration. The traps we include in our model are the water ice line, the disk heat transition, and the dead zone outer edge. We reduce our model parameter set to two physical parameters: the opacity of the accreting planetary atmospheres (κenv) and a measure of the efficiency of planetary accretion after gap opening (fmax). We perform planet population synthesis calculations based on the initial observed distributions of host star and disk properties - their disk masses, lifetimes, and stellar metallicities. We find the frequency of giant planet formation scales with disk metallicity, in agreement with the observed Jovian planet frequency-metallicity relation. We consider both X-ray and cosmic ray disk ionization models, whose differing ionization rates lead to different dead zone trap locations. In both cases, Jovian planets form in our model out to 2-3 AU, with a distribution at smaller radii dependent on the disk ionization source and the setting of envelope opacity. We find that low values of κenv (0.001-0.002 cm2 g-1) and X-ray disk ionization are necessary to obtain a separation between hot Jupiters near 0.1 AU, and warm Jupiters outside 0.6 AU, a feature present in the data. Our model also produces a large number of super Earths, but the majority are outside of 2 AU. As our model assumes a constant dust to gas ratio, we suggest that radial dust evolution must be taken into account to reproduce the observed super Earth population.

77 FR 18709 - Quality Assurance Requirements for Continuous Opacity Monitoring Systems at Stationary Sources

Federal Register 2010, 2011, 2012, 2013, 2014

2012-03-28

... Quality Assurance Requirements for Continuous Opacity Monitoring Systems at Stationary Sources AGENCY... direct final rule titled ``Quality Assurance Requirements for Continuous Opacity Monitoring Systems at...--Quality Assurance Requirements for Continuous Opacity Monitoring Systems at Stationary Sources Docket, EPA...

Replicating the Z iron opacity experiments on the NIF

NASA Astrophysics Data System (ADS)

Perry, T. S.; Heeter, R. F.; Opachich, Y. P.; Ross, P. W.; Kline, J. L.; Flippo, K. A.; Sherrill, M. E.; Dodd, E. S.; DeVolder, B. G.; Cardenas, T.; Archuleta, T. N.; Craxton, R. S.; Zhang, R.; McKenty, P. W.; Garcia, E. M.; Huffman, E. J.; King, J. A.; Ahmed, M. F.; Emig, J. A.; Ayers, S. L.; Barrios, M. A.; May, M. J.; Schneider, M. B.; Liedahl, D. A.; Wilson, B. G.; Urbatsch, T. J.; Iglesias, C. A.; Bailey, J. E.; Rochau, G. A.

2017-06-01

X-ray opacity is a crucial factor of all radiation-hydrodynamics calculations, yet it is one of the least validated of the material properties in the simulation codes. Recent opacity experiments at the Sandia Z-machine have shown up to factors of two discrepancies between theory and experiment, casting doubt on the validity of the opacity models. Therefore, a new experimental opacity platform is being developed on the National Ignition Facility (NIF) not only to verify the Z-machine experimental results but also to extend the experiments to other temperatures and densities. The first experiments will be directed towards measuring the opacity of iron at a temperature of ∼160 eV and an electron density of ∼7 × 1021 cm-3. Preliminary experiments on NIF have demonstrated the ability to create a sufficiently bright point backlighter using an imploding plastic capsule and also a hohlraum that can heat the opacity sample to the desired conditions. The first of these iron opacity experiments is expected to be performed in 2017.

A Case of Bilateral Descemet's Membrane and Subepithelial Opacity: In vivo Laser Confocal Microscopic Study.

PubMed

Hatta, Yukiko; Yokogawa, Hideaki; Kobayashi, Akira; Torisaki, Makoto; Sugiyama, Kazuhisa

2013-01-01

To report the in vivo laser confocal microscopy findings from a patient with Descemet's membrane and subepithelial opacity OU. A healthy 41-year-old male with Descemet's membrane and subepithelial opacity OU was studied. Routine ophthalmic examination, standard slit-lamp biomicroscopy, and in vivo laser confocal microscopic analysis of the entire corneal layer were performed. Slit-lamp biomicroscopy revealed subepithelial opacity in the mid-peripheral to peripheral cornea and numerous opacities located at the level of Descemet's membrane. It was difficult to distinguish the precise histological location of the opacity. In vivo laser confocal microscopy showed numerous hyperreflective particles in the subepithelium to superficial stroma and hyperreflectivity of Descemet's membrane. No abnormalities could be detected in the epithelial cell layer, midstromal layer, deep stromal layer, or endothelial cell layer. Although the origin of the corneal opacities was unclear, in vivo laser confocal microscopy was useful for observing microstructural abnormalities in a case of Descemet's membrane and subepithelial opacity.

A Case of Bilateral Descemet's Membrane and Subepithelial Opacity: In vivo Laser Confocal Microscopic Study

PubMed Central

Hatta, Yukiko; Yokogawa, Hideaki; Kobayashi, Akira; Torisaki, Makoto; Sugiyama, Kazuhisa

2013-01-01

Purpose To report the in vivo laser confocal microscopy findings from a patient with Descemet's membrane and subepithelial opacity OU. Case Report A healthy 41-year-old male with Descemet's membrane and subepithelial opacity OU was studied. Routine ophthalmic examination, standard slit-lamp biomicroscopy, and in vivo laser confocal microscopic analysis of the entire corneal layer were performed. Slit-lamp biomicroscopy revealed subepithelial opacity in the mid-peripheral to peripheral cornea and numerous opacities located at the level of Descemet's membrane. It was difficult to distinguish the precise histological location of the opacity. In vivo laser confocal microscopy showed numerous hyperreflective particles in the subepithelium to superficial stroma and hyperreflectivity of Descemet's membrane. No abnormalities could be detected in the epithelial cell layer, midstromal layer, deep stromal layer, or endothelial cell layer. Conclusion Although the origin of the corneal opacities was unclear, in vivo laser confocal microscopy was useful for observing microstructural abnormalities in a case of Descemet's membrane and subepithelial opacity. PMID:23626574

Calibrated simulations of Z opacity experiments that reproduce the experimentally measured plasma conditions

DOE PAGES

Nagayama, T.; Bailey, J. E.; Loisel, G.; ...

2016-02-05

Recently, frequency-resolved iron opacity measurements at electron temperatures of 170–200 eV and electron densities of (0.7 – 4.0) × 10 22 cm –3 revealed a 30–400% disagreement with the calculated opacities [J. E. Bailey et al., Nature (London) 517, 56 (2015)]. The discrepancies have a high impact on astrophysics, atomic physics, and high-energy density physics, and it is important to verify our understanding of the experimental platform with simulations. Reliable simulations are challenging because the temporal and spatial evolution of the source radiation and of the sample plasma are both complex and incompletely diagnosed. In this article, we describe simulationsmore » that reproduce the measured temperature and density in recent iron opacity experiments performed at the Sandia National Laboratories Z facility. The time-dependent spectral irradiance at the sample is estimated using the measured time- and space-dependent source radiation distribution, in situ source-to-sample distance measurements, and a three-dimensional (3D) view-factor code. The inferred spectral irradiance is used to drive 1D sample radiation hydrodynamics simulations. The images recorded by slit-imaged space-resolved spectrometers are modeled by solving radiation transport of the source radiation through the sample. We find that the same drive radiation time history successfully reproduces the measured plasma conditions for eight different opacity experiments. These results provide a quantitative physical explanation for the observed dependence of both temperature and density on the sample configuration. Simulated spectral images for the experiments without the FeMg sample show quantitative agreement with the measured spectral images. The agreement in spectral profile, spatial profile, and brightness provides further confidence in our understanding of the backlight-radiation time history and image formation. Furthermore, these simulations bridge the static-uniform picture of the data interpretation and the dynamic-gradient reality of the experiments, and they will allow us to quantitatively assess the impact of effects neglected in the data interpretation.« less

The Knuckle-Cracker's Dilemma: A Transaction Log Study of OPAC Subject Searching.

ERIC Educational Resources Information Center

Ferl, Terry Ellen; Milsap, Larry

1996-01-01

Researchers studying subject searching distributed an online questionnaire to users who access the University of California's online public access catalog, MELVYL, from public access terminals in the libraries of the University of California at Santa Cruz. This article discusses the results of transaction log analysis, comparison of in-library and…

Dust Coagulation in Infalling Protostellar Envelopes I. Compact Grains

NASA Technical Reports Server (NTRS)

Yorke, H.; Suttner, G.; Lin, D.

1999-01-01

Dust plays a key role in the optical, thermodynamic and gas dynamical behavior of collapsing molecular cores. Because of relative velocities of the individual dust grains, coagulation and shattering can modify the grain size distribution and due to corresponding changes in the medium's opacity significantly influence the evolution during early phase of star formation.

Dust Coagulation in Infalling Protostellar Envelopes I. Compact Grains

NASA Technical Reports Server (NTRS)

Yorke, H.; Lin, D.; Suttner, G.

1999-01-01

Dust plays a key role in the optical, thermodynamic and gas dynamical behavior of collapsing molecular cores. Because of relative velocities of the individual dust grains, coagulation and shattering can modify the grain size distribution and -- due to corresponding changes in the medium's opacity significantly -- influence the evolution during early phases of star formation.

MASS ESTIMATES OF RAPIDLY MOVING PROMINENCE MATERIAL FROM HIGH-CADENCE EUV IMAGES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Williams, David R.; Baker, Deborah; Van Driel-Gesztelyi, Lidia, E-mail: d.r.williams@ucl.ac.uk

We present a new method for determining the column density of erupting filament material using state-of-the-art multi-wavelength imaging data. Much of the prior work on filament/prominence structure can be divided between studies that use a polychromatic approach with targeted campaign observations and those that use synoptic observations, frequently in only one or two wavelengths. The superior time resolution, sensitivity, and near-synchronicity of data from the Solar Dynamics Observatory's Advanced Imaging Assembly allow us to combine these two techniques using photoionization continuum opacity to determine the spatial distribution of hydrogen in filament material. We apply the combined techniques to SDO/AIA observationsmore » of a filament that erupted during the spectacular coronal mass ejection on 2011 June 7. The resulting 'polychromatic opacity imaging' method offers a powerful way to track partially ionized gas as it erupts through the solar atmosphere on a regular basis, without the need for coordinated observations, thereby readily offering regular, realistic mass-distribution estimates for models of these erupting structures.« less

Systematic measurements of opacity dependence on temperature, density, and atomic number at stellar interior conditions

NASA Astrophysics Data System (ADS)

Nagayama, Taisuke

2017-10-01

Model predictions for iron opacity are notably different from measurements performed at matter conditions similar to the boundary between the solar radiation and convection zones. The calculated iron opacities have narrower spectral lines, weaker quasi-continuum at short wavelength, and deeper opacity windows than the measurements. If correct, these measurements help resolve a decade old problem in solar physics. A key question is therefore: What is responsible for the model-data discrepancy? The answer is complex because the experiments are challenging and opacity theories depend on multiple entangled physical processes such as the influence of completeness and accuracy of atomic states, line broadening, contributions from myriad transitions from excited states, and multi-photon absorption processes. To help determine the cause of this discrepancy, a systematic study of opacity variation with temperature, density, and atomic number is underway. Measurements of chromium, iron, and nickel opacities have been performed at two different temperatures and densities. The collection of measured opacities provides constraints on hypotheses to explain the discrepancy. We will discuss implications of measured opacities, experimental errors, and possible opacity model refinements. Sandia National Laboratories is a multi-mission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC., a wholly owned subsidiary of Honeywell International, Inc., for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-NA0003525.

Thus Spake the OPAC User.

ERIC Educational Resources Information Center

Markey, Karen

1983-01-01

Findings of focused-group interviews conducted for OCLC study of library users and online public access catalogs (OPACs) indicate users like OPACs, have problems finding right subject heading, envision features to improve subject access, want access to more than books, and want OPACs to provide new services. Eight references are listed. (EJS)

A Determination of the Intergalactic Redshift Dependent UV-Optical-NIR Photon Density Using Deep Galaxy Survey Data and the Gamma-Ray Opacity of the Universe

NASA Technical Reports Server (NTRS)

Stecker, Floyd W.

2012-01-01

We calculate the intensity and photon spectrum of the intergalactic background light (IBL) as a function of red shift using an approach based on observational data obtained at in different wavelength bands from local to deep galaxy surveys. Our empirically based approach allows us, for the firs.t time, to obtain a completely model independent determination of the IBL and to quantify its uncertainties. Using our results on the IBL, we then place upper and lower limits on the opacity of the universe to gamma-rays, independent of previous constraints.

Optical properties of highly compressed polystyrene: An ab initio study

DOE PAGES

Hu, S. X.; Collins, L. A.; Colgan, J. P.; ...

2017-10-16

Using all-electron density functional theory, we have performed an ab initio study on x ray absorption spectra of highly compressed polystyrene (CH). Here, we found that the K-edge shifts in strongly coupled, degenerate polystyrene cannot be explained by existing continuum-lowering models adopted in traditional plasma physics. To gain insights into the K edge shift in warm, dense CH, we have developed a model designated as “single-mixture-in-a-box” (SMIAB), which incorporates both the lowering of continuum and the rising of Fermi surface resulting from high compression. This simple SMIAB model correctly predicts the K-edge shift of carbon in highly compressed CH inmore » good agreement with results from quantum-molecular-dynamics (QMD) calculations. Traditional opacity models failed to give the proper K-edge shifts as the CH density increased. Based on QMD calculations, we have established a first-principles opacity table (FPOT) for CH in a wide range of densities and temperatures [p = 0.1 to 100 g/cm 3 and T = 2000 to 1,000,000 K]. The FPOT gives much higher Rosseland mean opacity compared to the cold-opacity–patched astrophysics opacity table for warm, dense CH and favorably compares to the newly improved Los Alamos ATOMIC model for moderately compressed CH (pCH ≤10 g/cm 3) but remains a factor of 2 to 3 higher at extremely high densities (pCH ≥ 50 g/cm 3). We anticipate the established FPOT of CH will find important applications to reliable designs of high-energy-density experiments. Moreover, the understanding of K-edge shifting revealed in this study could provide guides for improving the traditional opacity models to properly handle the strongly coupled and degenerate conditions.« less

Optical properties of highly compressed polystyrene: An ab initio study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hu, S. X.; Collins, L. A.; Colgan, J. P.

Using all-electron density functional theory, we have performed an ab initio study on x ray absorption spectra of highly compressed polystyrene (CH). Here, we found that the K-edge shifts in strongly coupled, degenerate polystyrene cannot be explained by existing continuum-lowering models adopted in traditional plasma physics. To gain insights into the K edge shift in warm, dense CH, we have developed a model designated as “single-mixture-in-a-box” (SMIAB), which incorporates both the lowering of continuum and the rising of Fermi surface resulting from high compression. This simple SMIAB model correctly predicts the K-edge shift of carbon in highly compressed CH inmore » good agreement with results from quantum-molecular-dynamics (QMD) calculations. Traditional opacity models failed to give the proper K-edge shifts as the CH density increased. Based on QMD calculations, we have established a first-principles opacity table (FPOT) for CH in a wide range of densities and temperatures [p = 0.1 to 100 g/cm 3 and T = 2000 to 1,000,000 K]. The FPOT gives much higher Rosseland mean opacity compared to the cold-opacity–patched astrophysics opacity table for warm, dense CH and favorably compares to the newly improved Los Alamos ATOMIC model for moderately compressed CH (pCH ≤10 g/cm 3) but remains a factor of 2 to 3 higher at extremely high densities (pCH ≥ 50 g/cm 3). We anticipate the established FPOT of CH will find important applications to reliable designs of high-energy-density experiments. Moreover, the understanding of K-edge shifting revealed in this study could provide guides for improving the traditional opacity models to properly handle the strongly coupled and degenerate conditions.« less

Replicating the Z iron opacity experiments on the NIF

DOE Office of Scientific and Technical Information (OSTI.GOV)

Perry, T. S.; Heeter, R. F.; Opachich, Y. P.

Here, X-ray opacity is a crucial factor of all radiation-hydrodynamics calculations, yet it is one of the least validated of the material properties in the simulation codes. Recent opacity experiments at the Sandia Z-machine have shown up to factors of two discrepancies between theory and experiment, casting doubt on the validity of the opacity models. Therefore, a new experimental opacity platform is being developed on the National Ignition Facility (NIF) not only to verify the Z-machine experimental results but also to extend the experiments to other temperatures and densities. The first experiments will be directed towards measuring the opacity ofmore » iron at a temperature of ~160 eV and an electron density of ~7 x 10 21 cm -3. Preliminary experiments on NIF have demonstrated the ability to create a sufficiently bright point backlighter using an imploding plastic capsule and also a hohlraum that can heat the opacity sample to the desired conditions. The first of these iron opacity experiments is expected to be performed in 2017.« less

Replicating the Z iron opacity experiments on the NIF

DOE PAGES

Perry, T. S.; Heeter, R. F.; Opachich, Y. P.; ...

2017-05-12

Here, X-ray opacity is a crucial factor of all radiation-hydrodynamics calculations, yet it is one of the least validated of the material properties in the simulation codes. Recent opacity experiments at the Sandia Z-machine have shown up to factors of two discrepancies between theory and experiment, casting doubt on the validity of the opacity models. Therefore, a new experimental opacity platform is being developed on the National Ignition Facility (NIF) not only to verify the Z-machine experimental results but also to extend the experiments to other temperatures and densities. The first experiments will be directed towards measuring the opacity ofmore » iron at a temperature of ~160 eV and an electron density of ~7 x 10 21 cm -3. Preliminary experiments on NIF have demonstrated the ability to create a sufficiently bright point backlighter using an imploding plastic capsule and also a hohlraum that can heat the opacity sample to the desired conditions. The first of these iron opacity experiments is expected to be performed in 2017.« less

Wavelength Does Not Equal Pressure: Vertical Contribution Functions and Their Implications for Mapping Hot Jupiters

NASA Astrophysics Data System (ADS)

Dobbs-Dixon, Ian; Cowan, Nicolas B.

2017-12-01

Multi-band phase variations, in principle, allow us to infer the longitudinal temperature distributions of planets as a function of height in their atmospheres. For example, 3.6 μm emission originates from deeper layers of the atmosphere than 4.5 μm due to greater water vapor absorption at the longer wavelength. Because heat transport efficiency increases with pressure, we expect thermal phase curves at 3.6 μm to exhibit smaller amplitudes and greater phase offsets than at 4.5 μm—yet this trend is not observed. Of the seven hot Jupiters with full-orbit phase curves at 3.6 and 4.5 μm, all of them have greater phase amplitude at 3.6 μm than at 4.5 μm, while four of the seven exhibit a greater phase offset at 3.6 μm. We use a 3D radiative-hydrodynamic model to calculate theoretical phase curves of HD 189733b, assuming thermo-chemical equilibrium. The model exhibits temperature, pressure, and wavelength-dependent opacity, primarily driven by carbon chemistry: CO is energetically favored on the dayside, while CH4 is favored on the cooler nightside. Infrared opacity, therefore, changes by orders of magnitude between day and night, producing dramatic vertical shifts in the wavelength-specific photospheres, which would complicate eclipse or phase mapping with spectral data. The model predicts greater relative phase amplitude and greater phase offset at 3.6 μm than at 4.5 μm, in agreement with the data. Our model qualitatively explains the observed phase curves, but it is in tension with current thermo-chemical kinetics models that predict zonally uniform atmospheric composition due to the transport of CO from the hot regions of the atmosphere.

Observational Constraints on Submillimeter Dust Opacity

NASA Astrophysics Data System (ADS)

Shirley, Yancy L.; Huard, Tracy L.; Pontoppidan, Klaus M.; Wilner, David J.; Stutz, Amelia M.; Bieging, John H.; Evans, Neal J., II

2011-02-01

Infrared extinction maps and submillimeter dust continuum maps are powerful probes of the density structure in the envelope of star-forming cores. We make a direct comparison between infrared and submillimeter dust continuum observations of the low-mass Class 0 core, B335, to constrain the ratio of submillimeter to infrared opacity (κsmm/κir) and the submillimeter opacity power-law index (κ vprop λ-β). Using the average value of theoretical dust opacity models at 2.2 μm, we constrain the dust opacity at 850 and 450 μm. Using new dust continuum models based upon the broken power-law density structure derived from interferometric observations of B335 and the infall model derived from molecular line observations of B335, we find that the opacity ratios are \\frac{\\kappa _{850}}{\\kappa _{2.2}} = (3.21{--}4.80)^{+0.44}_{-0.30} \\times 10^{-4} and \\frac{\\kappa _{450}}{\\kappa _{2.2}} = (12.8{--}24.8)^{+2.4}_{-1.3} \\times 10^{-4}with a submillimeter opacity power-law index of βsmm = (2.18-2.58)+0.30 -0.30. The range of quoted values is determined from the uncertainty in the physical model for B335. For an average 2.2 μm opacity of 3800 ± 700 cm2 g-1, we find a dust opacity at 850 and 450 μm of κ850 = (1.18-1.77)+0.36 -0.24 and κ450 = (4.72-9.13)+1.9 -0.98 cm2 g-1 of dust. These opacities are from (0.65-0.97)κOH5 850 of the widely used theoretical opacities of Ossenkopf and Henning for coagulated ice grains with thin mantles at 850 μm.

Influence of Projection Operator on Oxygen Line Shapes and its effect on Rosseland-Mean Opacity in Stellar Interiors

NASA Astrophysics Data System (ADS)

Gomez, Thomas; Nagayama, Taisukue; Kilcrease, David; Hansen, Stephanie; Montgomery, Mike; Winget, Don

2018-01-01

The Rosseland-Mean opacity (RMO) is an important quantity in determining radiation transport through stars. The solar-convection-zone boundary predicted by the standard solar model disagrees with helioseismology measurements by many sigma; a 14% increase in the RMO would resolve this discrepancy. Experiments at Sandia National Laboratories are now measuring iron opacity at solar-interior conditions, and significant discrepancies are already observed. Highly-ionized oxygen is one of the dominant contributions to the RMO. The strongest line, Lyman alpha, is at the peak of the Rosseland weighting function. The accuracy of line-broadening calculations has been called into question due to various experimental results and comparisons between theory. We have developed an ab-initio calculation to explore different physical effects, our current focus is treating penetrating collisions explicitly. The equation of motion used to calculate line shapes within the relaxation and unified theories includes a projection operator, which performs an average over plasma electron states; this is neglected due to past calculations approximate treatment of penetrations. We now include this projection term explicitly, which results in a significant broadening of spectral lines from highly-charged ions (low-Z elements are not much affected). The additional broadening raises the O Ly-alpha wing opacity by a factor of 5; we examine the consequences of this additional broadening on the Rosseland mean.

Redesigning the OPAC: Moving outside the ILMS

ERIC Educational Resources Information Center

Sokvitne, Lloyd O.

2006-01-01

The need to develop new OPACs that meet the needs of users better is becoming well acknowledged. How libraries can transform their OPACs to modern web friendly formats is not yet clear. This paper describes the State Library of Tasmania's experience in developing a new OPAC by exporting bibliographic data to a software package outside the ILMS.…

E-Referencer: Transforming Boolean OPACs to Web Search Engines.

ERIC Educational Resources Information Center

Khoo, Christopher S. G.; Poo, Danny C. C.; Toh, Teck-Kang; Hong, Glenn

E-Referencer is an expert intermediary system for searching library online public access catalogs (OPACs) on the World Wide Web. It is implemented as a proxy server that mediates the interaction between the user and Boolean OPACs. It transforms a Boolean OPAC into a retrieval system with many of the search capabilities of Web search engines.…

40 CFR 62.15215 - What is required for my continuous opacity monitoring system and how are the data used?

Code of Federal Regulations, 2011 CFR

2011-07-01

... opacity monitoring system and how are the data used? 62.15215 Section 62.15215 Protection of Environment... required for my continuous opacity monitoring system and how are the data used? (a) Install, calibrate, maintain, and operate a continuous opacity monitoring system. (b) Install, evaluate, and operate each...

A new description of Titan's aerosol optical properties from the analysis of VIMS Emission Phase Function observations

NASA Astrophysics Data System (ADS)

Maltagliati, Luca; Rodriguez, Sebastien; Sotin, Christophe; Rannou, Pascal; Bezard, Bruno; Cornet, Thomas

2016-06-01

The Huygens probe gave unprecedented information on the properties of Titan's aerosols (vertical distribution, opacity as a function of wavelength, phase function, single scattering albedo) by in-situ measurements (Tomasko et al. 2008). Being the only existing in-situ atmospheric probing for Titan, this aerosol model currently is the reference for many Titan studies (e.g. by being applied as physical input in radiative transfer models of the atmosphere). Recently a reanalysis of the DISR dataset, corroborated by data from the Downward-Looking Visible Spectrometer (DLVS), was carried out by the same group (Doose et al. 2016), leading to significant changes to the indications given by Tomasko et al. (2008). Here we present the analysis of the Emission Phase Function observation (EPF) performed by VIMS during the Cassini flyby T88 (November 2012). An EPF observes the same spot on the surface (and thus the same atmosphere) with the same emergence angle but with different incidence angles. In this way, our EPF allows, for the first time, to have direct information on the phase function of Titan's aerosols, as well as on other important physical parameters of the aerosols as the behavior of their extinction as a function of wavelength and the single scattering albedo (also as a function of wavelength) for the whole VIMS range (0.8-5.2 µm). The T88 EPF is composed of 25 VIMS datacubes spanning a scattering angle range approximately from 0°to 70°. We used the radiative transfer model described in Hirtzig et al. (2013) as baseline, updated with improved methane (+ related isotopes) spectroscopy. By changing the aerosol description in the model, we found the combination of aerosol optical parameters that fits best a constant aerosol column density over the whole set of the VIMS datacubes. We confirmed that the new results from Doose et al. (2016) do improve the fit for what concerns the vertical profile and the extinction as a function of wavelength. However, a different phase function with respect to what they propose must be employed, especially in the trend towards the backscattering peak. We also find that darker aerosols are needed in order to reproduce the value of the column opacity measured in-situ by Huygens.

A new description of Titan's aerosol optical properties from the analysis of VIMS Emission Phase Function observations

NASA Astrophysics Data System (ADS)

Rodriguez, Sebastien; Maltagliati, Luca; Sotin, Christophe; Rannou, Pascal; Bézard, Bruno; Cornet, Thomas

2016-10-01

The Huygens probe gave unprecedented information on the properties of Titan's aerosols (vertical distribution, opacity as a function of wavelength, phase function, single scattering albedo) by in-situ measurements (Tomasko et al. 2008). Being the only existing in-situ atmospheric probing for Titan, this aerosol model currently is the reference for many Titan studies (e.g. by being applied as physical input in radiative transfer models of the atmosphere). Recently a reanalysis of the DISR dataset, corroborated by data from the Downward-Looking Visible Spectrometer (DLVS), was carried out by the same group (Doose et al. 2016), leading to significant changes to the indications given by Tomasko et al. (2008).Here we present the analysis of the Emission Phase Function observation (EPF) performed by VIMS during the Cassini flyby T88 (November 2012). An EPF observes the same spot on the surface (and thus the same atmosphere) with the same emergence angle but with different incidence angles. In this way, our EPF allows, for the first time, to have direct information on the phase function of Titan's aerosols, as well as on other important physical parameters of the aerosols as the behavior of their extinction as a function of wavelength and the single scattering albedo (also as a function of wavelength) for the whole VIMS range (0.8-5.2 μm). The T88 EPF is composed of 25 VIMS datacubes spanning a scattering angle range approximately from 0°to 70°.We used the radiative transfer model described in Hirtzig et al. (2013) as baseline, updated with improved methane (+ related isotopes) spectroscopy. By changing the aerosol description in the model, we found the combination of aerosol optical parameters that fits best a constant aerosol column density over the whole set of the VIMS datacubes. We confirmed that the new results from Doose et al. (2016) do improve the fit for what concerns the vertical profile and the extinction as a function of wavelength. However, a different phase function with respect to what they propose must be employed, especially in the trend towards the backscattering peak. We also find that darker aerosols are needed in order to reproduce the value of the column opacity measured in-situ by Huygens.

Characterization of Forest Opacity Using Multi-Angular Emission and Backscatter Data

NASA Technical Reports Server (NTRS)

Kurum, Mehmet; O'Neill, Peggy; Lang, Roger H.; Joseph, Alicia T.; Cosh, Michael H.; Jackson, Thomas J.

2010-01-01

This paper discusses the results from a series of field experiments using ground-based L-band microwave active/passive sensors. Three independent approaches are employed to the microwave data to determine vegetation opacity of coniferous trees. First, a zero-order radiative transfer model is fitted to multi-angular microwave emissivity data in a least-square sense to provide "effective" vegetation optical depth. Second, a ratio between radar backscatter measurements with the corner reflector under trees and in an open area is calculated to obtain "measured" tree propagation characteristics. Finally, the "theoretical" propagation constant is determined by forward scattering theorem using detailed measurements of size/angle distributions and dielectric constants of the tree constituents (trunk, branches, and needles). The results indicate that "effective" values underestimate attenuation values compared to both "theoretical" and "measured" values.

Diagnostic performance of qualitative shear-wave elastography according to different color map opacities for breast masses.

PubMed

Kim, Hana; Youk, Ji Hyun; Gweon, Hye Mi; Kim, Jeong-Ah; Son, Eun Ju

2013-08-01

To compare the diagnostic performance of qualitative shear-wave elastography (SWE) according to three different color map opacities for breast masses 101 patients aged 21-77 years with 113 breast masses underwent B-mode US and SWE under three different color map opacities (50%, 19% and 100%) before biopsy or surgery. Following SWE features were reviewed: visual pattern classification (pattern 1-4), color homogeneity (Ehomo) and six-point color score of maximum elasticity (Ecol). Combined with B-mode US and SWE, the likelihood of malignancy (LOM) was also scored. The area under the curve (AUC) was obtained by ROC curve analysis to assess the diagnostic performance under each color opacity. A visual color pattern, Ehomo, Ecol and LOM scoring were significantly different between benign and malignant lesions under all color opacities (P<0.001). For 50% opacity, AUCs of visual color pattern, Ecol, Ehomo and LOM scoring were 0.902, 0.951, 0.835 and 0.975. But, for each SWE feature, there was no significant difference in the AUC among three different color opacities. For all color opacities, visual color pattern and Ecol showed significantly higher AUC than Ehomo. In addition, a combined set of B-mode US and SWE showed significantly higher AUC than SWE alone for color patterns, Ehomo, but no significant difference was found in Ecol. Qualitative SWE was useful to differentiate benign from malignant breast lesion under all color opacities. The difference in color map opacity did not significantly influence diagnostic performance of SWE. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

A higher-than-predicted measurement of iron opacity at solar interior temperatures.

PubMed

Bailey, J E; Nagayama, T; Loisel, G P; Rochau, G A; Blancard, C; Colgan, J; Cosse, Ph; Faussurier, G; Fontes, C J; Gilleron, F; Golovkin, I; Hansen, S B; Iglesias, C A; Kilcrease, D P; MacFarlane, J J; Mancini, R C; Nahar, S N; Orban, C; Pain, J-C; Pradhan, A K; Sherrill, M; Wilson, B G

2015-01-01

Nearly a century ago it was recognized that radiation absorption by stellar matter controls the internal temperature profiles within stars. Laboratory opacity measurements, however, have never been performed at stellar interior conditions, introducing uncertainties in stellar models. A particular problem arose when refined photosphere spectral analysis led to reductions of 30-50 per cent in the inferred amounts of carbon, nitrogen and oxygen in the Sun. Standard solar models using the revised element abundances disagree with helioseismic observations that determine the internal solar structure using acoustic oscillations. This could be resolved if the true mean opacity for the solar interior matter were roughly 15 per cent higher than predicted, because increased opacity compensates for the decreased element abundances. Iron accounts for a quarter of the total opacity at the solar radiation/convection zone boundary. Here we report measurements of wavelength-resolved iron opacity at electron temperatures of 1.9-2.3 million kelvin and electron densities of (0.7-4.0) × 10(22) per cubic centimetre, conditions very similar to those in the solar region that affects the discrepancy the most: the radiation/convection zone boundary. The measured wavelength-dependent opacity is 30-400 per cent higher than predicted. This represents roughly half the change in the mean opacity needed to resolve the solar discrepancy, even though iron is only one of many elements that contribute to opacity.

40 CFR 60.1270 - What is required for my continuous opacity monitoring system and how are the data used?

Code of Federal Regulations, 2011 CFR

2011-07-01

... opacity monitoring system and how are the data used? 60.1270 Section 60.1270 Protection of Environment... Continuous Emission Monitoring § 60.1270 What is required for my continuous opacity monitoring system and how... system. (b) Install, evaluate, and operate each continuous opacity monitoring system according to § 60.13...

Quantification of plume opacity by digital photography.

PubMed

Du, Ke; Rood, Mark J; Kim, Byung J; Kemme, Michael R; Franek, Bill; Mattison, Kevin

2007-02-01

The United States Environmental Protection Agency (USEPA) developed Method 9 to describe how plume opacity can be quantified by humans. However, use of observations by humans introduces subjectivity, and is expensive due to semiannual certification requirements of the observers. The Digital Opacity Method (DOM) was developed to quantify plume opacity at lower cost, with improved objectivity, and to provide a digital record. Photographs of plumes were taken with a calibrated digital camera under specified conditions. Pixel values from those photographs were then interpreted to quantify the plume's opacity using a contrast model and a transmission model. The contrast model determines plume opacity based on pixel values that are related to the change in contrast between two backgrounds that are located behind and next to the plume. The transmission model determines the plume's opacity based on pixel values that are related to radiances from the plume and its background. DOM was field tested with a smoke generator. The individual and average opacity errors of DOM were within the USEPA Method 9 acceptable error limits for both field campaigns. Such results are encouraging and support the use of DOM as an alternative to Method 9.

NLTE opacity calculations: C-Si and C-Ge mixtures

NASA Astrophysics Data System (ADS)

Jarrah, W.; Benredjem, D.; Pain, J.-C.; Dubau, J.

2017-09-01

The opacity is an important issue in the knowledge of the radiative properties of ICF and astrophysical plasmas. We present the opacity of dopants (silicon, germanium) embedded in the ablator of some ICF capsules. In recent works, Hill and Rose calculated the opacity of silicon in LTE and non-LTE plasmas, while Minguez and co-workers focused on the opacity of carbon. We have used the Cowan code to calculate the atomic structure of carbon, silicon and germanium in various ionic stages. The cross-sections of atomic processes (collisional excitation, collisional ionization) are obtained by fitting the values given by the code FAC to the Van Regemorter-like formulas of Sampson and Zhang. A corrected Gaunt factor is then obtained. A collisional-radiative code was developed in order to obtain the ionic populations, the level populations and the opacity. Line broadening and line shift are taken into account. The ionization potential depression is included in our calculations. The effect of a radiation field on the opacity is examined.

The role of configuration interaction in the LTE opacity of Fe

NASA Astrophysics Data System (ADS)

Colgan, James; Kilcrease, David; Magee, Norm; Armstrong, Gregory; Abdallah, Joe; Sherrill, Manolo; Fontes, Christopher; Zhang, Honglin; Hakel, Peter

2013-05-01

The Los Alamos National Laboratory code ATOMIC has been recently used to generate a series of local-thermodynamic-equilibrium (LTE) light element opacities for the elements H through Ne. Our calculations, which include fine-structure detail, represent a systematic improvement over previous Los Alamos opacity calculations using the LEDCOP legacy code. Recent efforts have resulted in comprehensive new calculations of the opacity of Fe. In this presentation we explore the role of configuration interaction (CI) in the Fe opacity, and show where CI influences the monochromatic opacity. We present such comparisons for conditions of astrophysical interest. The Los Alamos National Laboratory is operated by Los Alamos National Security, LLC for the National Nuclear Security Administration of the U.S. Department of Energy under Contract No. DE-AC5206NA25396.

Epidemiological study of respiratory disease in workers exposed to polyvinylchloride dust.

PubMed Central

Soutar, C A; Copland, L H; Thornley, P E; Hurley, J F; Ottery, J; Adams, W G; Bennett, B

1980-01-01

The respiratory health of workers exposed to polyvinylchloride (PVC) dust has been investigated in 818 men sampled from the work force of a factory manufacturing PVC. In a cross-sectional survey, the lung function and prevalences of respiratory symptoms and chest radiographic abnormalities were compared with estimates of individual PVC dust exposures based on detailed occupational histories and current measurements of respirable PVC dust. Complaints of slight exertional dyspnoea were associated with PVC dust exposure, though age and smoking effects were much stronger. The forced expired volume in one second (FEV1) and forced vital capacity (FVC) were inversely related to dust exposure after age, height, and smoking effects had been taken into account. This effect was seen principally in cigarette smokers, and there was suggestive evidence that PVC dust exposure and cigarette smoking interacted in the reduction of FEV1 and FVC. Gas transfer factor was not related to dust exposure. The chest radiographs were read according to the ILO U/C classification by three experienced readers. One reader recorded a low prevalence of small rounded opacities, and these were not related to age or dust exposure. Another reader recorded a higher prevalence of small rounded opacities category 0/1 or more, and these were related to age but not to dust exposure. The third reader recorded the highest prevalence of small rounded opacities (though none greater than category 1/1), and these were independently related both to age and to PVC dust exposure, indicating an effect of PVC dust on the appearance of the chest radiography. These appearances were so slight that only the higher sensitivity of this reader in the interpretation of profusion of small rounded opacities on the ILO U/C scale enabled detection of this effect of PVC dust. In conclusion, exposure to PVC dust is associated with some deterioration of lung function, slight abnormalities of the chest radiograph, and complaints of slight dyspnoea. The mean decline in FEV1 associated with the average dust exposure experienced in the study was small, though some of the men with higher dust exposures may have suffered clinically important loss of lung function as a result of their occupation. PMID:7444838

Design of the opacity spectrometer for opacity measurements at the National Ignition Facility

DOE PAGES

Ross, P. W.; Heeter, R. F.; Ahmed, M. F.; ...

2016-10-03

Recent experiments at the Sandia National Laboratory Z facility have called into question models used in calculating opacity, of importance for modeling stellar interiors. An effort is being made to reproduce these results at the National Ignition Facility (NIF). These experiments require a new X-ray opacity spectrometer (OpSpec) spanning 540 eV–2100 eV with a resolving power E/ΔE > 700. The design of the OpSpec is presented. Photometric calculations based on expected opacity data are also presented in this paper. First use on NIF is expected in September 2016.

Design of the opacity spectrometer for opacity measurements at the National Ignition Facility.

PubMed

Ross, P W; Heeter, R F; Ahmed, M F; Dodd, E; Huffman, E J; Liedahl, D A; King, J A; Opachich, Y P; Schneider, M B; Perry, T S

2016-11-01

Recent experiments at the Sandia National Laboratory Z facility have called into question models used in calculating opacity, of importance for modeling stellar interiors. An effort is being made to reproduce these results at the National Ignition Facility (NIF). These experiments require a new X-ray opacity spectrometer (OpSpec) spanning 540 eV-2100 eV with a resolving power E/ΔE > 700. The design of the OpSpec is presented. Photometric calculations based on expected opacity data are also presented. First use on NIF is expected in September 2016.

A Comparative Study of Major OPACs in Selected Academic Libraries for Developing Countries: User Study and Subjective User Evaluation.

ERIC Educational Resources Information Center

Park, Iljong

1997-01-01

A study of five Texas academic libraries provided information on OPAC use by Korean college students to assist system managers select OPACs. The study determined that academic level and age influence preference for the type of OPAC system, that more specific search instructions are needed, and that system menus were the most commonly used source…

Radiographic features of cardiogenic pulmonary edema in dogs with mitral regurgitation: 61 cases (1998-2007).

PubMed

Diana, Alessia; Guglielmini, Carlo; Pivetta, Mauro; Sanacore, Antonina; Di Tommaso, Morena; Lord, Peter F; Cipone, Mario

2009-11-01

To evaluate radiographic distribution of pulmonary edema (PE) in dogs with mitral regurgitation (MR) and investigate the association between location of radiographic findings and direction of the mitral regurgitant jet (MRJ). Retrospective case series. 61 dogs with cardiogenic PE and MR resulting from mitral valve disease (MVD; 51 dogs), dilated cardiomyopathy (9), and hypertrophic cardiomyopathy (1). Thoracic radiographs of dogs with Doppler echocardiographic evidence of MR were reviewed for location (diffuse, perihilar, or focal) of PE. Also, direction (central or eccentric) of the MRJ, as evaluated by Doppler color flow mapping (DCFM), and distribution (symmetric or asymmetric) of radiographic findings were evaluated. Diffuse, perihilar, and focal increases in pulmonary opacity were observed in 11 (18.0%), 7 (11.5%), and 43 (70.5%) of 61 dogs, respectively. Radiographic evidence of asymmetric PE in a single lung lobe or 2 ipsilateral lobes was found in 21 dogs, with involvement of only the right caudal lung lobe in 17 dogs. Doppler color flow mapping of the MRJ was available for 46 dogs. Of 31 dogs with a central MRJ, 28 had radiographic findings indicative of symmetric PE. Of 15 dogs with eccentric MRJ, 11 had radiographic evidence of asymmetric PE, and all of these dogs had MVD. In dogs with cardiogenic PE, a symmetric radiographic distribution of increased pulmonary opacity was predominantly associated with a central MRJ, whereas an asymmetric radiographic distribution was usually associated with eccentric MRJ, especially in dogs with MVD.

Pulmonary Toxocariasis: Initial and Follow-Up CT Findings in 63 Patients.

PubMed

Lee, Kyung Hee; Kim, Tae Jung; Lee, Kyung Won

2015-06-01

The objective of our study was to describe the characteristic radiologic findings of pulmonary toxocariasis on initial and follow-up chest CT. Between June 2010 and May 2014, 63 patients with serologically proven, clinically diagnosed pulmonary toxocariasis and chest CT examinations performed within 2 months of an enzyme-linked immunosorbent assay for toxocariasis were identified. Two chest radiologists retrospectively analyzed the chest CT examinations in consensus; they focused on the distribution, location, number, and internal characteristics of the pulmonary lesions. The pulmonary lesions tended to involve three or more lobes (49% [31/63]) on the initial CT; predominance of the abnormalities in a subpleural location (81% [51/63]) and in the lower lung zone (98% [62/63]) was noted. The number of pulmonary lesions per patient were from two to five (46% [29/63]), more than five (32% [20/63]), or one (22% [14/63]). The radiologic findings of pulmonary toxocariasis could be categorized into four different patterns: ground-glass opacities (GGOs), solid nodules, consolidations, and linear opacities. The most common pattern was ill-defined GGOs with or without solid portions (84% [53/63]). The solid nodule and patchy consolidation patterns were found in 29% (18/63) and 21% (13/63) of patients, respectively. In addition, linear opacities (1-2 mm thick and 8-25 mm long) were present in 19% of patients (12/63); this finding is a subtle, yet novel, finding. On follow-up CT, the pulmonary lesions had either disappeared or migrated; when they had migrated, they revealed radiologic manifestations similar to the findings on the initial CT. Pulmonary toxocariasis manifested as multiple lesions in four radiologic patterns with subpleural and lower lung predominance on initial and follow-up CT. A linear opacity may be one of many clues in the diagnosis of pulmonary toxocariasis on CT.

Deep neural network convolution (NNC) for three-class classification of diffuse lung disease opacities in high-resolution CT (HRCT): consolidation, ground-glass opacity (GGO), and normal opacity

NASA Astrophysics Data System (ADS)

Hashimoto, Noriaki; Suzuki, Kenji; Liu, Junchi; Hirano, Yasushi; MacMahon, Heber; Kido, Shoji

2018-02-01

Consolidation and ground-glass opacity (GGO) are two major types of opacities associated with diffuse lung diseases. Accurate detection and classification of such opacities are crucially important in the diagnosis of lung diseases, but the process is subjective, and suffers from interobserver variability. Our study purpose was to develop a deep neural network convolution (NNC) system for distinguishing among consolidation, GGO, and normal lung tissue in high-resolution CT (HRCT). We developed ensemble of two deep NNC models, each of which was composed of neural network regression (NNR) with an input layer, a convolution layer, a fully-connected hidden layer, and a fully-connected output layer followed by a thresholding layer. The output layer of each NNC provided a map for the likelihood of being each corresponding lung opacity of interest. The two NNC models in the ensemble were connected in a class-selection layer. We trained our NNC ensemble with pairs of input 2D axial slices and "teaching" probability maps for the corresponding lung opacity, which were obtained by combining three radiologists' annotations. We randomly selected 10 and 40 slices from HRCT scans of 172 patients for each class as a training and test set, respectively. Our NNC ensemble achieved an area under the receiver-operating-characteristic (ROC) curve (AUC) of 0.981 and 0.958 in distinction of consolidation and GGO, respectively, from normal opacity, yielding a classification accuracy of 93.3% among 3 classes. Thus, our deep-NNC-based system for classifying diffuse lung diseases achieved high accuracies for classification of consolidation, GGO, and normal opacity.

Measurement of nurses' attitudes and knowledge regarding acute care older patients: Psychometrics of the OPACS-US combined with the KOP-Q.

PubMed

Dikken, Jeroen; Hoogerduijn, Jita G; Lagerwey, Mary D; Shortridge-Baggett, Lillie; Klaassen, Sharon; Schuurmans, Marieke J

In clinical practice, identifying positive and negative attitudes toward older patients is very important to improve quality of care provided to them. The Older People in Acute Care Survey - United States (OPACS-US) is an instrument measuring hospital nurses attitudes regarding older patients. However, psychometrics have never been assessed. Furthermore, knowledge being related to attitude and behavior should also be measured complementing the OPACS-US. The purpose of this study was to assess structural validity and reliability of the OPACS-US and assess whether the OPACS-US can be complemented with the Knowledge about Older Patients-Quiz (KOP-Q). A multicenter cross sectional design was conducted. Registered nurses (n = 130, mean age 39,9 years; working experience 14,6 years) working in four general hospitals were included in the study. Nurses completed the OPACS-US section A: practice experiences, B: general opinion and the KOP-Q online. Findings demonstrated that the OPACS-US is a valid and reliable survey instrument that measures practice experiences and general opinion. Furthermore, the OPACS-US can be combined with the KOP-Q adding a knowledge construct, and is ready for use within education and/or quality improvement programs in the USA. Copyright © 2017 Elsevier Inc. All rights reserved.

Scale covariant gravitation. V - Kinetic theory. VI - Stellar structure and evolution

NASA Technical Reports Server (NTRS)

Hsieh, S.-H.; Canuto, V. M.

1981-01-01

A scale covariant kinetic theory for particles and photons is developed. The mathematical framework of the theory is given by the tangent bundle of a Weyl manifold. The Liouville equation is derived, and solutions to corresponding equilibrium distributions are presented and shown to yield thermodynamic results identical to the ones obtained previously. The scale covariant theory is then used to derive results of interest to stellar structure and evolution. A radiative transfer equation is derived that can be used to study stellar evolution with a variable gravitational constant. In addition, it is shown that the sun's absolute luminosity scales as L approximately equal to GM/kappa, where kappa is the stellar opacity. Finally, a formula is derived for the age of globular clusters as a function of the gravitational constant using a previously derived expression for the absolute luminosity.

Wider pulsation instability regions for β Cephei and SPB stars calculated using new Los Alamos opacities

DOE Office of Scientific and Technical Information (OSTI.GOV)

Walczak, Przemysław; Fontes, Christopher John; Colgan, James Patrick

Here, our goal is to test the newly developed OPLIB opacity tables from Los Alamos National Laboratory and check their influence on the pulsation properties of B-type stars. We calculated models using MESA and Dziembowski codes for stellar evolution and linear, nonadiabatic pulsations, respectively. We derived the instability domains of β Cephei and SPB-types for different opacity tables OPLIB, OP, and OPAL. As a result, the new OPLIB opacities have the highest Rosseland mean opacity coefficient near the so-called Z-bump. Therefore, the OPLIB instability domains are wider than in the case of OP and OPAL data.

Wider pulsation instability regions for β Cephei and SPB stars calculated using new Los Alamos opacities

DOE PAGES

Walczak, Przemysław; Fontes, Christopher John; Colgan, James Patrick; ...

2015-08-13

Here, our goal is to test the newly developed OPLIB opacity tables from Los Alamos National Laboratory and check their influence on the pulsation properties of B-type stars. We calculated models using MESA and Dziembowski codes for stellar evolution and linear, nonadiabatic pulsations, respectively. We derived the instability domains of β Cephei and SPB-types for different opacity tables OPLIB, OP, and OPAL. As a result, the new OPLIB opacities have the highest Rosseland mean opacity coefficient near the so-called Z-bump. Therefore, the OPLIB instability domains are wider than in the case of OP and OPAL data.

Investigating the Effect of Cosmic Opacity on Standard Candles

NASA Astrophysics Data System (ADS)

Hu, J.; Yu, H.; Wang, F. Y.

2017-02-01

Standard candles can probe the evolution of dark energy over a large redshift range. But the cosmic opacity can degrade the quality of standard candles. In this paper, we use the latest observations, including Type Ia supernovae (SNe Ia) from the “joint light-curve analysis” sample and Hubble parameters, to probe the opacity of the universe. A joint fitting of the SNe Ia light-curve parameters, cosmological parameters, and opacity is used in order to avoid the cosmological dependence of SNe Ia luminosity distances. The latest gamma-ray bursts are used in order to explore the cosmic opacity at high redshifts. The cosmic reionization process is considered at high redshifts. We find that the sample supports an almost transparent universe for flat ΛCDM and XCDM models. Meanwhile, free electrons deplete photons from standard candles through (inverse) Compton scattering, which is known as an important component of opacity. This Compton dimming may play an important role in future supernova surveys. From analysis, we find that about a few per cent of the cosmic opacity is caused by Compton dimming in the two models, which can be corrected.

Validation of the digital opacity compliance system under regulatory enforcement conditions.

PubMed

McFarland, Michael J; Rasmussen, Steve L; Stone, Daniel A; Palmer, Glenn R; Wander, Joseph D

2006-09-01

U.S. Environmental Protection Agency (EPA) Emission Measurement Center in conjunction with EPA Regions VI and VIII, the state of Utah, and the U.S. Department of Defense have conducted a series of long-term pilot and field tests to determine the accuracy and reliability of a visible opacity monitoring system consisting of a conventional digital camera and a separate computer software application for plume opacity determination. This technology, known as the Digital Opacity Compliance System (DOCS), has been successfully demonstrated at EPA-sponsored Method-9 "smoke schools", as well as at a number of government and commercially operated industrial facilities. Results from the current DOCS regulatory pilot study demonstrated that, under regulatory enforcement conditions, the average difference in opacity measurement between the DOCS technology and EPA Reference Method 9 (Method 9) was 1.12%. This opacity difference, which was computed from the evaluation of 241 regulated air sources, was found to be statistically significant at the 99% confidence level. In evaluating only those sources for which a nonzero visible opacity level was recorded, the

Atomic structure data based on average-atom model for opacity calculations in astrophysical plasmas

NASA Astrophysics Data System (ADS)

Trzhaskovskaya, M. B.; Nikulin, V. K.

2018-03-01

Influence of the plasmas parameters on the electron structure of ions in astrophysical plasmas is studied on the basis of the average-atom model in the local thermodynamic equilibrium approximation. The relativistic Dirac-Slater method is used for the electron density estimation. The emphasis is on the investigation of an impact of the plasmas temperature and density on the ionization stages required for calculations of the plasmas opacities. The level population distributions and level energy spectra are calculated and analyzed for all ions with 6 ≤ Z ≤ 32 occurring in astrophysical plasmas. The plasma temperature range 2 - 200 eV and the density range 2 - 100 mg/cm3 are considered. The validity of the method used is supported by good agreement between our values of ionization stages for a number of ions, from oxygen up to uranium, and results obtained earlier by various methods among which are more complicated procedures.

A New Generation of Los Alamos Opacity Tables

DOE PAGES

Colgan, James Patrick; Kilcrease, David Parker; Magee, Jr., Norman H.; ...

2016-01-26

We present a new, publicly available, set of Los Alamos OPLIB opacity tables for the elements hydrogen through zinc. Our tables are computed using the Los Alamos ATOMIC opacity and plasma modeling code, and make use of atomic structure calculations that use fine-structure detail for all the elements considered. Our equation-of-state (EOS) model, known as ChemEOS, is based on the minimization of free energy in a chemical picture and appears to be a reasonable and robust approach to determining atomic state populations over a wide range of temperatures and densities. In this paper we discuss in detail the calculations thatmore » we have performed for the 30 elements considered, and present some comparisons of our monochromatic opacities with measurements and other opacity codes. We also use our new opacity tables in solar modeling calculations and compare and contrast such modeling with previous work.« less

Experiment to measure oxygen opacity at high density and temperature

NASA Astrophysics Data System (ADS)

Keiter, Paul; Mussack, Katie; Orban, Chris; Colgan, James; Ducret, Jean-Eric; Fontes, Christopher J.; Guzik, Joyce Ann; Heeter, Robert F.; Kilcrease, Dave; Le Pennec, Maelle; Mancini, Roberto; Perry, Ted; Turck-Chièze, Sylvaine; Trantham, Matt

2017-06-01

In recent years, there has been a debate over the abundances of heavy elements (Z >2) in the solar interior. Recent solar atmosphere models [Asplund 2009] find a significantly lower abundance for C, N, and O compared to models used roughly a decade ago. This discrepancy has led to an investigation of opacities through laboratory experiments and improved opacity models for many of the larger contributors to the sun’s opacity, including iron and oxygen. Recent opacity measurements of iron disagree with opacity model predictions [Bailey et al, 2015]. Although these results are still controversial, repeated scrutiny of the experiment and data has not produced a conclusive reason for the discrepancy. New models have been implemented in the ATOMIC opacity code for C, O and Fe to address the solar abundance issue [Colgan, 2013]. Armstrong et al [2014] have also implemented changes in the ATOMIC code for low-Z elements. However, no data currently exists to test the low-Z material models in the regime relevant to the solar convection zone. We present an experimental design using the opacity platform developed at the National Ignition Facility to study the oxygen opacity at densities and temperatures near the solar convection zone conditions.This work is funded by the U.S. DOE, through the NNSA-DS and SC-OFES Joint Program in HEDPLP, grant No. DE-NA0001840, and the NLUF Program, grant No. DE-NA0000850, and through LLE, University of Rochester by the NNSA/OICF under Agreement No. DE-FC52-08NA28302.

A computer-aided differential diagnosis between UIP and NSIP using automated assessment of the extent and distribution of regional disease patterns at HRCT: comparison with the radiologist's decision

NASA Astrophysics Data System (ADS)

Kim, Namkug; Seo, Joon Beom; Park, Sang Ok; Lee, Youngjoo; Lee, Jeongjin

2009-02-01

To evaluate the accuracy of computer aided differential diagnosis (CADD) between usual interstitial pneumonia (UIP) and nonspecific interstitial pneumonia (NSIP) at HRCT in comparison with that of a radiologist's decision. A computerized classification for six local disease patterns (normal, NL; ground-glass opacity, GGO; reticular opacity, RO; honeycombing, HC; emphysema, EM; and consolidation, CON) using texture/shape analyses and a SVM classifier at HRCT was used for pixel-by-pixel labeling on the whole lung area. The mode filter was applied on the results to reduce noise. Area fraction (AF) of each pattern, directional probabilistic density function (pdf) (dPDF: mean, SD, skewness of pdf /3 directions: superior-inferior, anterior-posterior, central-peripheral), regional cluster distribution pattern (RCDP: number, mean, SD of clusters, mean, SD of centroid of clusters) were automatically evaluated. Spatially normalized left and right lungs were evaluated separately. Disease division index (DDI) on every combination of AFs and asymmetric index (AI) between left and right lung ((left-right)/left) were also evaluated. To assess the accuracy of the system, fifty-four HRCT data sets in patients with pathologically diagnosed UIP (n=26) and NSIP (n=28) were used. For a classification procedure, a CADD-SVM classifier with internal parameter optimization, and sequential forward floating feature selection (SFFS) were employed. The accuracy was assessed by a 5-folding cross validation with 20- times repetition. For comparison, two thoracic radiologists reviewed the whole HRCT images without clinical information and diagnose each case either as UIP or NSIP. The accuracies of radiologists' decision were 0.75 and 0.87, respectively. The accuracies of the CADD system using the features of AF, dPDF, AI of dPDF, RDP, AI of RDP, DDI were 0.70, 0.79, 0.77, 0.80, 0.78, 0.81, respectively. The accuracy of optimized CADD using all features after SFFS was 0.91. We developed the CADD system to differentiate between UIP and NSIP using automated assessment of the extent and distribution of regional disease patterns at HRCT.

Overview of Graphical User Interfaces.

ERIC Educational Resources Information Center

Hulser, Richard P.

1993-01-01

Discussion of graphical user interfaces for online public access catalogs (OPACs) covers the history of OPACs; OPAC front-end design, including examples from Indiana University and the University of Illinois; and planning and implementation of a user interface. (10 references) (EA)

Impact of Neutrino Opacities on Core-collapse Supernova Simulations

NASA Astrophysics Data System (ADS)

Kotake, Kei; Takiwaki, Tomoya; Fischer, Tobias; Nakamura, Ko; Martínez-Pinedo, Gabriel

2018-02-01

The accurate description of neutrino opacities is central to both the core-collapse supernova (CCSN) phenomenon and the validity of the explosion mechanism itself. In this work, we study in a systematic fashion the role of a variety of well-selected neutrino opacities in CCSN simulations where the multi-energy, three-flavor neutrino transport is solved using the isotropic diffusion source approximation (IDSA) scheme. To verify our code, we first present results from one-dimensional (1D) simulations following the core collapse, bounce, and ∼250 ms postbounce of a 15 {M}ȯ star using a standard set of neutrino opacities by Bruenn. A detailed comparison with published results supports the reliability of our three-flavor IDSA scheme using the standard opacity set. We then investigate in 1D simulations how individual opacity updates lead to differences with the baseline run with the standard opacity set. Through detailed comparisons with previous work, we check the validity of our implementation of each update in a step-by-step manner. Individual neutrino opacities with the largest impact on the overall evolution in 1D simulations are selected for systematic comparisons in our two-dimensional (2D) simulations. Special attention is given to the criterion of explodability in the 2D models. We discuss the implications of these results as well as its limitations and the requirements for future, more elaborate CCSN modeling.

Effects of adhesive used as modeling liquid on the stability of the color and opacity of composites.

PubMed

Araujo, Fernanda Santos; Barros, Mellany Cristie Ramos; Santana, Márcia Luciana Carregosa; de Jesus Oliveira, Ludmila Smith; Silva, Paula Fernanda Damasceno; Lima, Giana da Silveira; Faria-E-Silva, André Luis

2018-04-01

This study evaluated the effects of adhesive type used as modeling liquid on the stability of the color and opacity of composites submitted to thermal cycling in staining solutions followed by a bleaching procedure. Thirty cylinder-shaped composite specimens (10 mm diameter × 1.5 mm thickness) were built using or not using (control) an adhesive (Adper Universal or Scotchbond Multipurpose) as the modeling liquid. After polishing procedures, the color and opacity were measured, and the specimens were submitted to 200 thermal cycles with 10 s of dwell time in baths of grape juice at 5°C, water at 37°C, and coffee at 55°C. Changes in opacity and color caused by the staining solutions were measured. Then, the specimens were bleached with 35% hydrogen peroxide for 45 minutes followed by color/opacity measurements. Data were analyzed by ANOVA and Tukey's test (α = 0.05). The use of modeling liquids did not affect the initial color and opacity of composite. Reduced changes to color (E 00  = 3.44) and opacity (+2.67%) were observed for specimens modeled using Adper Universal. Bleaching procedures reduced the color (E 00  = 1.9-3.8) and opacity (-2.3 to 3.1%) alterations caused by staining solutions but were unable to restore the values observed at baseline. The use of universal adhesive as modeling liquid significantly reduced the color and opacity changes caused by staining solutions, and the bleaching procedure partially re-established the opacity and color of the composites. This study evaluates whether using adhesive systems for modeling a composite affects the color and opacity changes caused by staining solutions followed by a bleaching procedure. The findings suggest that the use of a universal adhesive as modeling liquid can reduce the alterations in optical properties caused by staining solutions, and the application of high-concentrated hydrogen peroxide over the composite reduce the color changes without fully recover the initial color. © 2018 Wiley Periodicals, Inc.

Effect of partial wave parameter identification on IOS opacities and integral cross sections for rotationally inelastic collisions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pack, R.T

1977-02-15

The effect of identification of the partial wave parameter of the J/sub z/ CCS and IOS approximations as an orbital angular momentum rather than the total angular momentum is studied. Comparison with accurate close coupling calculations for Ar--N/sub 2/ and He--CO/sub 2/ collisions is made, and it is found that this identification results in a marked improvement, both quantitative and qualitative, in calculated IOS opacity functions and integral cross sections for both elastic and inelastic collisions. Use of the correct energy in the cross section formula also makes a marked improvement even though T matrices are computed with an averagemore » energy. (AIP)« less

Pediatric genetic disease of the cornea

PubMed Central

Fecarotta, Christopher M.; Huang, Wendy W.

2014-01-01

Our objective is to evaluate the literature regarding selected genetic diseases of the cornea, including megalocornea, keratoglobus, keratoconus, cystinosis, the mucopolysaccharidoses, sclerocornea, Peters' anomaly, familial dysautonomia, and various corneal dystrophies. The transparency of the cornea is a consequence of uniformity in both size and spacing of the collagen lamellae. The cornea's clarity depends on a delicate biochemical and structural balance; consequently, genetic disorders that disrupt either its metabolic or anatomic function can cause opacity and vision loss. Many childhood corneal diseases have a genetic etiology and are associated with known syndromes. Each disorder has unique associated set of possible complications. Prognosis often depends on the extent of opacity and disorganization of the anterior segment. Corneal transplantation has been performed for these disorders with variable success. PMID:27625877

Water clouds and dust aerosols observations with PFS MEX at Mars

NASA Astrophysics Data System (ADS)

Zasova, L.; Formisano, V.; Moroz, V.; Grassi, D.; Ignatiev, N.; Giuranna, M.; Hansen, G.; Blecka, M.; Ekonomov, A.; Lellouch, E.; Fonti, S.; Grigoriev, A.; Hirsch, H.; Khatuntsev, I.; Mattana, A.; Maturilli, A.; Moshkin, B.; Patsaev, D.; Piccioni, G.; Rataj, M.; Saggin, B.

2005-08-01

Observations of water ice clouds and dust are among the main scientific goals of the Planetary Fourier Spectrometer (PFS), a payload instrument of the European Mars Express mission. We report some results, obtained in three orbits: 37, 41 and 68. The temperature profile, and dust and water ice cloud opacities are retrieved from the thermal infrared (long-wavelength channel of PFS) in a self-consistent way using the same spectrum. Orographic ice clouds are identified above Olympus (orbit 37) and Ascraeus Mons (orbit 68). Both volcanoes were observed near noon at Ls=337° and 342°, respectively. The effective radius of ice particles is preliminary estimated as 1-3 μm, changing along the flanks. The corresponding visual opacity changes in the interval 0.2-0.4 above Olympus and 0.1-0.6 above Ascraeus Mons. In the case of Ascraeus Mons, the ice clouds were observed mainly above the Southern flank of the volcano with maximum opacity near the summit. In the case of Olympus, the clouds were found above both sides of the top. A different type of ice cloud is observed at latitudes above 50°N (orbit 68) in the polar hood: the effective particle radius is estimated to be 4 μm. Below the 1 mb level an inversion in the temperature profiles is found with maximum temperature at around 0.6 mb. Along orbit 68 it appears above Alba Patera, then it increases to the north and decreases above the CO 2 polar cap. Beginning from latitude 20°S above Tharsis (orbit 68), the ice clouds and dust contribute equally to the spectral shape. Further on, the ice clouds are found everywhere along orbit 68 up to the Northern polar cap, except the areas between the Northern flank of Ascraeus Mons (below 10 km) and the edge of Alba Patera. Orbit 41 is shifted from the orbit 68 by roughly 180° longitude and passes through Hellas. Ice clouds are not visible in this orbit at latitudes below 80°S. The dust opacity is anticorrelated with the surface altitude. From 70°S to 25°N latitude the vertical dust distribution follows an exponential law with a scale height of 11.5±0.5 km, which corresponds to the gaseous scale height near noon and indicates a well-mixed condition. The 9 μm dust opacity, reduced to zero surface altitude, is found to be 0.25±0.05, which corresponds to a visual opacity of 0.5-0.7 (depending on the particle size).

Characterization of the atmosphere above a site for millimeter wave astronomy

NASA Astrophysics Data System (ADS)

Nasir, Francesco Tony; Buffa, Franco; Deiana, Gian Luigi

2011-04-01

The Sardinia Radio Telescope (SRT) is a challeging scientific project managed by the National Institute for Astrophysics (INAF), it is being developed at 30 km North of the city of Cagliari, Italy. The goal of the SRT project is to build a general purpose, fully steerable, 64 m diameter radio telescope, capable of operating with high efficiency in the centimeter and millimeter frequency range (0.3-100 GHz). In portions of this frequency range, especially towards the high end, astronomical observations can be heavily deteriorated by non-optimal atmospheric conditions, especially by water vapor content. The water molecule permanent electric dipole in fact, leads to pressure broadened rotational transitions around the 22.23 GHz spectral line. Furthermore, water vapor's continuum absorption and emission may influence higher frequency observations too. To a lower degree, cloud liquid black body radiation can also affect centimeter and millimeter observations. In addition to this, inhomogeneities in water vapor distributions can cause signal phase errors which introduce a great amount of uncertainty to VLBI mode observations. The Astronomical Observatory of Cagliari (OA-CA) has obtained historical timeseries of radiosonde profiles conducted at the airport of Cagliari. Through the radiosonde measurements and an appropriate radiative transfer model, we have performed a statistical analysis of the SRT site's atmosphere which accounts for atmospheric opacity at different frequencies, integrated water vapor (IWV), integrated liquid water (ILW) and cloud cover distributions during the year. This will help to investigate in which period of the year astronomical observations at different frequencies should be performed preferably. The results show that, at the SRT site, K-band astronomical observations are possible all year round, the median opacity at 22.23 GHz is 0.10 Np in the winter (Dec-Jan-Feb) and 0.16 Np in the summer (Jun-Jul-Aug). Integrated water vapor during winter months ranges, on average, between 7 and 15 mm. Cloud cover is usually not present for more than 36% of the time during the year. The atmospheric opacity study indicates that observations at higher frequencies (50-100 GHz) may be performed usefully: the median opacity at 100 GHz is usually below or equal to 0.2 Np in the period that ranges from January to April.

Measurement of dust optical depth using the solar irradiance sensor (SIS) onboard the ExoMars 2016 EDM

NASA Astrophysics Data System (ADS)

Toledo, D.; Arruego, I.; Apéstigue, V.; Jiménez, J. J.; Gómez, L.; Yela, M.; Rannou, P.; Pommereau, J.-P.

2017-04-01

The solar irradiance sensor (SIS) was included in the DREAMS package onboard the ExoMars 2016 Entry Descent and Landing Demonstrator Module, and has been selected in the METEO meteorological station onboard the ExoMars 2020 Lander. This instrument is designed to measure at different time intervals the scattered flux or the sum of direct flux and scattered flux in UVA (315-400 nm) and NIR (700-1100 nm) bands. For SIS'16, these measurements are performed by a total of 3 sensors per band placed at the faces of a truncated tetrahedron with face inclination angles of 60°. The principal goal of SIS'16 design is to perform measurements of the dust opacity in UVA and NIR wavelengths ranges, crucial parameters in the understanding of the Martian dust cycle. The retrieval procedure is based on the use of radiative transfer simulations to reproduce SIS observations acquired during daytime as a function of dust opacity. Based on different sensitivity analysis, the retrieval procedure also requires to include as free parameters (1) the dust effective radius; (2) the dust effective variance; and (3) the imaginary part of the refractive index of dust particles in UVA band. We found that the imaginary part of the refractive index of dust particles does not have a big impact on NIR signal, and hence we can kept constant this parameter in the retrieval of dust opacity at this channel. In addition to dust opacity measurements, this instrument is also capable to detect and characterize clouds by looking at the time variation of the color index (CI), defined as the ratio between the observations in NIR and UVA channels, during daytime or twilight. By simulating CI signals with a radiative transfer model, the cloud opacity and cloud altitude (only during twilight) can be retrieved. Here the different retrieval procedures that are used to analyze SIS measurements, as well as the results obtained in different sensitivity analysis, are presented and discussed.

Invisible excess of sense in social interaction

PubMed Central

Koubová, Alice

2014-01-01

The question of visibility and invisibility in social understanding is examined here. First, the phenomenological account of expressive phenomena and key ideas of the participatory sense-making theory are presented with regard to the issue of visibility. These accounts plead for the principal visibility of agents in interaction. Although participatory sense-making does not completely rule out the existence of opacity and invisible aspects of agents in interaction, it assumes the capacity of agents to integrate disruptions, opacity and misunderstandings in mutual modulation. Invisibility is classified as the dialectical counterpart of visibility, i.e., as a lack of sense whereby the dynamics of perpetual asking, of coping with each other and of improvements in interpretation are brought into play. By means of empirical exemplification this article aims at demonstrating aspects of invisibility in social interaction which complement the enactive interpretation. Without falling back into Cartesianism, it shows through dramaturgical analysis of a practice called “(Inter)acting with the inner partner” that social interaction includes elements of opacity and invisibility whose role is performative. This means that opacity is neither an obstacle to be overcome with more precise understanding nor a lack of meaning, but rather an excess of sense, a “hiddenness” of something real that has an “active power” (Merleau-Ponty). In this way it contributes to on-going social understanding as a hidden potentiality that naturally enriches, amplifies and in part constitutes human participation in social interactions. It is also shown here that this invisible excess of sense already functions on the level of self-relationship due to the essential self-opacity and self-alterity of each agent of social interaction. The analysis consequently raises two issues: the question of the enactive ethical stance toward the alterity of the other and the question of the autonomy of the self-opaque agent. PMID:25324798

Low-contrast detectability in volume rendering: a phantom study on multidetector-row spiral CT data.

PubMed

Shin, Hoen-Oh; Falck, Christian V; Galanski, Michael

2004-02-01

To cope with the increasing amount of CT data, there is growing interest in direct volume-rendering techniques (VRT) as a diagnostic tool. The aim of this phantom study was to analyze the low-contrast detectability (LCD) of VRT compared with multi-planar reformations (MPR). Soft tissue lesions were simulated by spheres of different diameters (3-8 mm). The average lesion density was 15 HU compared with a background density of 35 HU. Two different CT protocols with 40 and 150 mAs were performed on a multi-detector row CT. The scanning parameters were as following: 140 kV; 2x0.5-mm slice collimation; pitch 2 (table movement per rotation/single slice collimation), and reconstruction with 0.5-mm slice thickness at 0.5-mm interval. A B30 kernel was used for reconstruction. The VRT was performed by mapping Hounsfield values to gray levels equal to a CT window (center: 60 HU; window: 370 HU ). A linear ramp was applied for the opacity transfer function varying the maximum opacity between 0.1 and 1.0. A statistical method based on the Rose model was used to calculate the detection threshold depending on lesion size and image noise. Additionally, clinical data of 2 patients with three liver lesions of different sizes and density were evaluated. In VRT, LCD was most dependent on object size. Regarding lesions larger than 5 mm, VRT is significantly superior to MPR (p<0.05) for all opacity settings. In lesions sized 3-5 mm a maximum opacity level approximately 40-50% showed a near equivalent detectability in VRT and MPR. For higher opacity levels VRT was superior to MPR. Only for 3-mm lesions MPR performed slightly better in low-contrast detectability (p<0.05). Compared with MPR, VRT shows similar performance in LCD. Due to noise suppression effects, it is suited for visualization of data with high noise content.

Pulmonary effects of exposure to fine fibreglass: irregular opacities and small airways obstruction.

PubMed Central

Kilburn, K H; Powers, D; Warshaw, R H

1992-01-01

OBJECTIVE--Man made mineral fibres imitate asbestos and produce tumours of the pleura in animals. To answer the question, Does prolonged exposure to fibreglass adversely affect pulmonary function or produce radiographic abnormalities in human subjects? we studied workers in a midwestern appliance plant where refrigerator doors and previously entire cabinets were insulated with fibreglass sheeting and loose rotary spun fibreglass. METHODS--Spirometry and lung volumes were measured, respiratory and occupational questionnaires were administered, and chest x-ray films were read for pneumoconiosis using International Labour Office (ILO) 1980 criteria in 284 workers with exposure of 20 years or more. RESULTS--Expiratory flows were reduced including FEV1 (mean 90.3% of predicted (pr), FEF25-75 (85.5% pr), and FEF75-85 (76.2% pr). Forced vital capacity was significantly reduced (92.8% pr) and total lung capacity was significantly increased (109.2% pr). In white male smokers, a group large enough for comparisons, parameters of pulmonary function were reduced further in the presence of irregular opacities. Forty three workers (15.1%) had evidence of pneumoconiosis on chest radiographs: 26 of these (9.1%), had no known exposure to asbestos and 17 (6.0%) had some exposure. The best judgement was that in 36 (13.0%), pulmonary opacities or pleural abnormalities were due to fibreglass. CONCLUSION--Commercial rotary spun fibreglass used for insulating appliances appears to produce human disease that is similar to asbestosis. PMID:1419860

Investigating the Effect of Cosmic Opacity on Standard Candles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hu, J.; Yu, H.; Wang, F. Y., E-mail: fayinwang@nju.edu.cn

Standard candles can probe the evolution of dark energy over a large redshift range. But the cosmic opacity can degrade the quality of standard candles. In this paper, we use the latest observations, including Type Ia supernovae (SNe Ia) from the “joint light-curve analysis” sample and Hubble parameters, to probe the opacity of the universe. A joint fitting of the SNe Ia light-curve parameters, cosmological parameters, and opacity is used in order to avoid the cosmological dependence of SNe Ia luminosity distances. The latest gamma-ray bursts are used in order to explore the cosmic opacity at high redshifts. The cosmicmore » reionization process is considered at high redshifts. We find that the sample supports an almost transparent universe for flat ΛCDM and XCDM models. Meanwhile, free electrons deplete photons from standard candles through (inverse) Compton scattering, which is known as an important component of opacity. This Compton dimming may play an important role in future supernova surveys. From analysis, we find that about a few per cent of the cosmic opacity is caused by Compton dimming in the two models, which can be corrected.« less

Comment on “Large Enhancement in High-Energy Photoionization of Fe XVII and Missing Continuum Plasma Opacity”

DOE PAGES

Blancard, C.; Colgan, J.; Cosse, Ph.; ...

2016-12-09

Recent R-matrix calculations claim to provide a significant enhancement in the opacity of Fe XVII due to atomic core excitations and assert that this enhancement is consistent with recent measurements of higher-than-predicted iron opacities. Here this comment shows that the standard opacity models which have already been directly compared with experimental data produce photon absorption cross-sections for Fe XVII that are effectively equivalent to the R-matrix opacities reported in.

The GUI OPAC: Approach with Caution.

ERIC Educational Resources Information Center

Hildreth, Charles R.

1995-01-01

Discusses the graphical user interface (GUI) online public access catalog (OPAC), a user interface that uses images to represent options. Topics include user interface design for information retrieval; designing effective bibliographic displays, including subject headings; two design principles; and what GUIs can bring to OPACs. (LRW)

The Effect of Ionic Correlations on Radiative Properties in the Solar Interior and Terrestrial Experiments

NASA Astrophysics Data System (ADS)

Krief, Menahem; Kurzweil, Yair; Feigel, Alexander; Gazit, Doron

2018-04-01

With the aim of solving the decade-old problem of solar opacity, we report substantial photoabsorption uncertainty due to the effect of ion–ion correlations. By performing detailed opacity calculations of the solar mixture, we find that taking into account the ionic structure changes the Rosseland opacity near the convection zone by ∼10%. We also report a ∼15% difference in the Rosseland opacity for iron, which was recently measured at the Sandia Z facility, where the temperature reached that prevailing in the convection zone boundary while the density was 2.5 times lower. Finally, we propose a method to measure opacities at solar temperatures and densities that have never been reached in the past via laboratory radiation flow experiments, by using plastic foams doped with permilles of dominant photon absorbers in the Sun. The method is advantageous for an experimental study of solar opacities that may lead to a resolution of the solar abundance problem.

Observations of the global haze redistribution on Titan from 2006 to 2015 with OSIRIS at Keck

NASA Astrophysics Data System (ADS)

Ádámkovics, Máté; de Pater, Imke

2017-07-01

We observed Titan with the OH Suppressing InfraRed Imaging Spectrograph (OSIRIS) at the W. M. Keck observatory from 2006 through 2015 using adaptive optics. The sunlight scattered by atmospheric haze was spatially resolved in the 2.0 μm (K) band window, and the spectra were analyzed with a radiative transfer model to determine the vertical (altitude) and meridional (latitudinal) variation in the haze distribution over this time period. This study complements recent work by Karkoschka (2016) in the season of observations, in the time span and sampling interval, in wavelength coverage and spectral resolution, as well as in the radiative transfer methodology and analysis. We observe the largest meridional gradient in haze opacity above 20 km toward the northern hemisphere in January 2010. Individual observations can show significant deviations from a relatively smooth linear gradient in haze across the entire disk. The variation in haze below 20 km is rarely well-described by a simple model and there is a systematically smaller amount of haze opacity retrieved from the equator to 10° S when observing the disk with a sub-observer longitude near 150° W. This correlation with longitude suggests one of the following; a localized decrease in haze scattering, a localized increase in gas opacity, or a systematic over-estimate of the surface albedo in this region.

Temperatures and aerosol opacities of the Mars atmosphere at aphelion: Validation and inter-comparison of limb sounding profiles from MRO/MCS and MGS/TES

NASA Astrophysics Data System (ADS)

Shirley, James H.; McConnochie, Timothy H.; Kass, David M.; Kleinböhl, Armin; Schofield, John T.; Heavens, Nicholas G.; McCleese, Daniel J.; Benson, Jennifer; Hinson, David P.; Bandfield, Joshua L.

2015-05-01

We exploit the relative stability and repeatability of the Mars atmosphere at aphelion for an inter-comparison of Mars Global Surveyor/Thermal Emission Spectrometer (MGS/TES) and Mars Reconnaissance Orbiter/Mars Climate Sounder (MRO/MCS) nighttime temperature profiles and aerosol opacity profiles in Mars years 25, 26, 29, 30, and 31. Cross-calibration of these datasets is important, as they together provide an extended climatology for this planetary atmosphere. As a standard of comparison we employ temperature profiles obtained by radio occultation methods during the MGS mission in Mars years 24, 25, and 26. We first compare both zonal mean TES limb sounding profiles and zonal mean MCS limb sounding profiles with zonal means of radio occultation temperature profiles for the same season (Ls = 70-80°) and latitudes (55-70°N). We employ a statistical z test for quantifying the degree of agreement of temperature profiles by pressure level. For pressures less than 610 Pa (altitudes > 3 km), the ensemble mean temperature difference between the radio occultation and TES limb sounding profiles found in these comparisons was 1.7 ± 0.7 K. The ensemble mean temperature difference between radio occultation and MCS profiles was 1.4 ± 1.0 K. These differences fall within the formal error estimates for both TES and MCS, validating the accuracy of the instruments and their respective retrieval algorithms. In the second phase of our investigation, we compare aphelion season zonal mean TES limb sounding temperature, water ice opacity, and dust opacity profiles with those obtained at the same latitudes in different years by MCS. The ensemble mean temperature difference found for three comparisons between TES and MCS zonal mean temperature profiles was 2.8 ± 2.1 K. MCS and TES temperatures between 610 Pa and 5 Pa from 55 to 70°N are largely in agreement (with differences < 2 K) when water ice aerosol opacities are comparable. Temperature differences increase when the opacities are dissimilar; TES profiles exhibit colder temperatures when TES water ice opacities are greater than those observed by MCS. Our comparisons reveal a possible systematic offset of TES and MCS temperatures at the highest altitudes resolved in the TES retrievals; TES temperatures are consistently colder than the corresponding MCS temperatures at pressures ⩽ 1 Pa (altitudes ⩾ 58 km). We otherwise find no evidence of systematic bias between TES limb sounding and MCS retrieved atmospheric quantities between 610 Pa and 1 Pa. Inter-annual variability is noted in comparisons of latitudinal temperature gradients from 55 to 70°N, in the amplitude of inversions linked with thermal tides in the middle atmosphere, and in the abundance and vertical distribution of water ice aerosols from 55 to 70°N during the aphelion season.

Infrared dust and millimeter-wave carbon monoxide emission in the Orion region

NASA Technical Reports Server (NTRS)

Bally, John; Langer, William D.; Liu, Weihong

1991-01-01

The far-infrared dust emission seen by the IRAS satellite in the Orion region is analyzed as a function of the local radiation field intensity, and the dust temperature and opacity are compared with (C-12)O and (C-13)O emission. The infrared radiation is interpreted within the framework of a single-component large grain model and a multicomponent grain model consisting of subpopulations of grains with size-dependent temperatures. A strong dependence of the 100-micron optical depth derived is found using the large grain model on the average line-of-sight dust temperature and radiation field. In the hot environment surrounding high-luminosity sources and H II regions, all dust along the line-of-sight radiates at 100 microns, and the dust-to-gas ratio, based on the 100-micron opacity and I(/C-13/O), appears to be in agreement with the standard value, about 1 percent by mass. A relationship is found between the inferred dust-to-gas ratio and the radiation field intensity responsible for heating the dust which can be used to estimate the gas column density from the dust opacity derived from the 60- and 100-micron IRAS fluxes.

Serendipity and Holism: The Beauty of OPACs.

ERIC Educational Resources Information Center

Rice, James

1988-01-01

Identifies factors which may account for user dissatisfaction with online public access catalogs (OPACs) and discusses some advantages of OPACs over card catalogs: (1) design for subject searching; (2) flexibility; (3) browsing capability; (4) precision; (5) availability of status information; and (6) development of microcomputer software to…

The wind geometry of the Wolf-Rayet star HD 191765

NASA Technical Reports Server (NTRS)

Schulte-Ladbeck, R. F.; Nordsieck, K. H.; Taylor, M.; Bjorkman, K. S.; Magalhaes, A. M.; Wolff, M. J.

1992-01-01

A time-dependent spectropolarimetric data set of HD 191765 in the wavelength range 3159-7593 A is presented. At all epochs the present observations display a large and strongly wavelength-dependent continuum polarization and reduced levels of polarization across the emission lines. The data imply a significant intrinsic continuum polarization which requires a general deviation of the electron distribution from spherical symmetry. The global shape is quite stable as a function of time; small fluctuations may arise from localized density/temperature changes. The line polarizations are consistent with an axisymmetric wind geometry and ionization stratification. A qualitative model for polarization in a Wolf-Rayet atmosphere is developed. It is argued that the blueward rise of the continuum polarization in HD 191765 can be explained if the density in the wind is high, resulting in a competition of thermal and electron-scattering continuum opacity in the vertical.

Stellar Atmospheric Parameterization Based on Deep Learning

NASA Astrophysics Data System (ADS)

Pan, R. Y.; Li, X. R.

2016-07-01

Deep learning is a typical learning method widely studied in machine learning, pattern recognition, and artificial intelligence. This work investigates the stellar atmospheric parameterization problem by constructing a deep neural network with five layers. The proposed scheme is evaluated on both real spectra from Sloan Digital Sky Survey (SDSS) and the theoretic spectra computed with Kurucz's New Opacity Distribution Function (NEWODF) model. On the SDSS spectra, the mean absolute errors (MAEs) are 79.95 for the effective temperature (T_{eff}/K), 0.0058 for lg (T_{eff}/K), 0.1706 for surface gravity (lg (g/(cm\\cdot s^{-2}))), and 0.1294 dex for metallicity ([Fe/H]), respectively; On the theoretic spectra, the MAEs are 15.34 for T_{eff}/K, 0.0011 for lg (T_{eff}/K), 0.0214 for lg (g/(cm\\cdot s^{-2})), and 0.0121 dex for [Fe/H], respectively.

40 CFR 60.2155 - May I conduct performance testing less often?

Code of Federal Regulations, 2010 CFR

2010-07-01

... pollutant (particulate matter, hydrogen chloride, or opacity) over 3 consecutive years show that you comply... limitation for particulate matter, hydrogen chloride, or opacity, you may choose to conduct performance tests... matter, hydrogen chloride, or opacity, you must conduct annual performance tests for that pollutant until...

TI-59 PROGRAMMABLE CALCULATOR PROGRAMS FOR IN-STACK OPACITY, VENTURI SCRUBBERS, AND ELECTROSTATIC PRECIPITATORS

EPA Science Inventory

The report explains the basic concepts of in-stack opacity as measured by in-stack opacity monitors. Also included are calculator programs that model the performance of venturi scrubbers and electrostatic precipitators. The effect of particulate control devices on in-stack opacit...

40 CFR 63.1357 - Temporary, conditioned exemption from particulate matter and opacity standards.

Code of Federal Regulations, 2011 CFR

2011-07-01

... particulate matter and opacity standards. 63.1357 Section 63.1357 Protection of Environment ENVIRONMENTAL... Cement Manufacturing Industry Other § 63.1357 Temporary, conditioned exemption from particulate matter... methods) is exempt from: (1) Any particulate matter and opacity standards of part 60 or part 63 of this...

Computing NLTE Opacities -- Node Level Parallel Calculation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Holladay, Daniel

Presentation. The goal: to produce a robust library capable of computing reasonably accurate opacities inline with the assumption of LTE relaxed (non-LTE). Near term: demonstrate acceleration of non-LTE opacity computation. Far term (if funded): connect to application codes with in-line capability and compute opacities. Study science problems. Use efficient algorithms that expose many levels of parallelism and utilize good memory access patterns for use on advanced architectures. Portability to multiple types of hardware including multicore processors, manycore processors such as KNL, GPUs, etc. Easily coupled to radiation hydrodynamics and thermal radiative transfer codes.

The effect of Livermore OPAL opacities on the evolutionary masses of RR Lyrae stars

NASA Technical Reports Server (NTRS)

Yi, Sukyoung; Lee, Young-Wook; Demarque, Pierre

1993-01-01

We have investigated the effect of the new Livermore OPAL opacities on the evolution of horizontal-branch (HB) stars. This work was motivated by the recent stellar pulsation calculations using the new Livermore opacities, which suggest that the masses of double-mode RR Lyrae stars are 0.1-0.2 solar mass larger than those based on earlier opacities. Unlike the pulsation calculations, we find that the effect of opacity change on the evolution of HB stars is not significant. In particular, the effect of the mean masses of RR Lyrae stars is very small, showing a decrease of only 0.01-0.02 solar mass compared to the models based on old Cox-Stewart opacities. Consequently, with the new Livermore OPAL opacities, both the stellar pulsation and evolution models now predict approximately the same masses for the RR Lyrae stars. Our evolutionary models suggest that the mean masses of the RR Lyrae stars are about 0.76 and about 0.71 solar mass for M15 (Oosterhoff group II) and M3 (group I), respectively. If (alpha/Fe) = 0.4, these values are decreased by about 0.03 solar mass. Variations of the mean masses of RR Lyrae stars with HB morphology and metallicity are also presented.

Computational design of short pulse laser driven iron opacity experiments

DOE PAGES

Martin, M. E.; London, R. A.; Goluoglu, S.; ...

2017-02-23

Here, the resolution of current disagreements between solar parameters calculated from models and observations would benefit from the experimental validation of theoretical opacity models. Iron's complex ionic structure and large contribution to the opacity in the radiative zone of the sun make iron a good candidate for validation. Short pulse lasers can be used to heat buried layer targets to plasma conditions comparable to the radiative zone of the sun, and the frequency dependent opacity can be inferred from the target's measured x-ray emission. Target and laser parameters must be optimized to reach specific plasma conditions and meet x-ray emissionmore » requirements. The HYDRA radiation hydrodynamics code is used to investigate the effects of modifying laser irradiance and target dimensions on the plasma conditions, x-ray emission, and inferred opacity of iron and iron-magnesium buried layer targets. It was determined that plasma conditions are dominantly controlled by the laser energy and the tamper thickness. The accuracy of the inferred opacity is sensitive to tamper emission and optical depth effects. Experiments at conditions relevant to the radiative zone of the sun would investigate the validity of opacity theories important to resolving disagreements between solar parameters calculated from models and observations.« less

Computational design of short pulse laser driven iron opacity experiments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Martin, M. E.; London, R. A.; Goluoglu, S.

Here, the resolution of current disagreements between solar parameters calculated from models and observations would benefit from the experimental validation of theoretical opacity models. Iron's complex ionic structure and large contribution to the opacity in the radiative zone of the sun make iron a good candidate for validation. Short pulse lasers can be used to heat buried layer targets to plasma conditions comparable to the radiative zone of the sun, and the frequency dependent opacity can be inferred from the target's measured x-ray emission. Target and laser parameters must be optimized to reach specific plasma conditions and meet x-ray emissionmore » requirements. The HYDRA radiation hydrodynamics code is used to investigate the effects of modifying laser irradiance and target dimensions on the plasma conditions, x-ray emission, and inferred opacity of iron and iron-magnesium buried layer targets. It was determined that plasma conditions are dominantly controlled by the laser energy and the tamper thickness. The accuracy of the inferred opacity is sensitive to tamper emission and optical depth effects. Experiments at conditions relevant to the radiative zone of the sun would investigate the validity of opacity theories important to resolving disagreements between solar parameters calculated from models and observations.« less

Global Modeling of Nebulae with Particle Growth, Drift, and Evaporation Fronts. I. Methodology and Typical Results

NASA Astrophysics Data System (ADS)

Estrada, Paul R.; Cuzzi, Jeffrey N.; Morgan, Demitri A.

2016-02-01

We model particle growth in a turbulent, viscously evolving protoplanetary nebula, incorporating sticking, bouncing, fragmentation, and mass transfer at high speeds. We treat small particles using a moments method and large particles using a traditional histogram binning, including a probability distribution function of collisional velocities. The fragmentation strength of the particles depends on their composition (icy aggregates are stronger than silicate aggregates). The particle opacity, which controls the nebula thermal structure, evolves as particles grow and mass redistributes. While growing, particles drift radially due to nebula headwind drag. Particles of different compositions evaporate at “evaporation fronts” (EFs) where the midplane temperature exceeds their respective evaporation temperatures. We track the vapor and solid phases of each component, accounting for advection and radial and vertical diffusion. We present characteristic results in evolutions lasting 2 × 105 years. In general, (1) mass is transferred from the outer to the inner nebula in significant amounts, creating radial concentrations of solids at EFs; (2) particle sizes are limited by a combination of fragmentation, bouncing, and drift; (3) “lucky” large particles never represent a significant amount of mass; and (4) restricted radial zones just outside each EF become compositionally enriched in the associated volatiles. We point out implications for millimeter to submillimeter SEDs and the inference of nebula mass, radial banding, the role of opacity on new mechanisms for generating turbulence, the enrichment of meteorites in heavy oxygen isotopes, variable and nonsolar redox conditions, the primary accretion of silicate and icy planetesimals, and the makeup of Jupiter’s core.

A Determination of the Intergalactic Redshift Dependent UV-Optical-NIR Photon Density Using Deep Galaxy Survey Data and the Gamma-ray Opacity of the Universe

NASA Technical Reports Server (NTRS)

Stecker, Floyd W.; Malkan, Matthew A.; Scully, Sean T.

2012-01-01

We calculate the intensity and photon spectrum of the intergalactic background light (IBL) as a function of redshift using an approach based on observational data obtained in many different wavelength bands from local to deep galaxy surveys. This allows us to obtain an empirical determination of the IBL and to quantify its observationally based uncertainties. Using our results on the IBL, we then place 68% confidence upper and lower limits on the opacity of the universe to gamma-rays, free of the theoretical assumptions that were needed for past calculations. We compare our results with measurements of the extragalactic background light and upper limits obtained from observations made by the Fermi Gamma-ray Space Telescope.

VizieR Online Data Catalog: Analytical model for irradiated atmospheres (Parmentier+, 2014)

NASA Astrophysics Data System (ADS)

Parmentier, V.; Guillot, G.

2013-11-01

The model have six parameters to describe the opacities: - Kappa(N) is the Rosseland mean opacity at each levels of the atmosphere it does not have to be constant with depth - Gp is the ratio of the thermal Plank mean opacity to the thermal Rosseland mean opacity - Beta is the width ratio of the two thermal bands in the frequency space - Gv1 is the ratio of the visible opacity in the first visible band to the thermal Rosseland mean opacity - Gv2 is the ratio of the visible opacity in the second visible band to the thermal Rosseland mean opacity - Betav is the width ratio of the two visible band in the frequency space Additional parameters describe the physical setting: - Tirr is the irradiation temperature, given by the stellar flux - mu is the angle between the vertical direction and the stellar direction - Tint is the internal temperature, given by the internal luminosity - P(i) are the pressure levels where the temperature is computed - grav is the gravity of the planet - N is the number of atmospheric levels The code and all the outputs uses SI units. Installation and use : to install the code use the command "make". The input parameters must be changed inside the file PaperI.f90. It is necessary to compile the code again each time. The subroutine Tprofile.f90 can be directly implemented into one's code. To launch the code, launch the executable file NonGrey. The output is in the file PTprofile.csv (4 data files).

A hydrodynamic treatment of the cold dark matter cosmological scenario

NASA Technical Reports Server (NTRS)

Cen, Renyue; Ostriker, Jeremiah

1992-01-01

The evolution of structure in a postrecombination Friedmann-Robertson-Walker universe containing both gaseous baryons and cold dark matter (CDM) is studied by means of an Eulerian code coupled with a standard particle-mesh code. Ionization state and radiative opacity are calculated in detail, and the hydrodynamic simulations make it possible to compute properties of gas distribution on scales larger than three cell sizes. The model yields a soft X-ray background consistent with the latest cosmic nucleosynthesis values, and can accurately reproduce the galaxy-galaxy two-point correlation. The rate of galaxy formation peaks at a relatively late epoch. With regard to mass function, the smallest objects are stabilized against collapse by thermal energy: the mass-weighted mass spectrum peaks in the vicinity of m(b) = 10 exp 9.2 solar masses with a reasonable fit to the Schecter luminosity function if the baryon mass to blue light ratio is approximately 4. Overall, the simulations provide strong support for the CMD scenario. Of particular interest is that, while the baryons are not biased on scales greater than 1/h Mpc, the galaxies are, and that the 'galaxies' have a correlation function of the required slope and the correct amplitude.

Graphical User Interfaces and Library Systems: End-User Reactions.

ERIC Educational Resources Information Center

Zorn, Margaret; Marshall, Lucy

1995-01-01

Describes a study by Parke-Davis Pharmaceutical Research Library to determine user satisfaction with the graphical user interface-based (GUI) Dynix Marquis compared with the text-based Dynix Classic Online Public Access Catalog (OPAC). Results show that the GUI-based OPAC was preferred by endusers over the text-based OPAC. (eight references) (DGM)

40 CFR Table 1 to Subpart Llllll... - Applicability of General Provisions to Subpart LLLLLL

Code of Federal Regulations, 2011 CFR

2011-07-01

... Modacrylic Fibers Production Area Sources Pt. 63, Subpt. LLLLLL, Table 1 Table 1 to Subpart LLLLLL of Part 63... not include opacity or visible emissions standards or require a continuous opacity monitoring system... does not require a continuous opacity monitoring system or continuous emissions monitoring system. 63.9...

40 CFR Table 1 to Subpart Llllll... - Applicability of General Provisions to Subpart LLLLLL

Code of Federal Regulations, 2010 CFR

2010-07-01

... Modacrylic Fibers Production Area Sources Pt. 63, Subpt. LLLLLL, Table 1 Table 1 to Subpart LLLLLL of Part 63... not include opacity or visible emissions standards or require a continuous opacity monitoring system... does not require a continuous opacity monitoring system or continuous emissions monitoring system. 63.9...

A Comparison of Keyword Subject Searching on Six British University OPACs Online Public Access Catalogs.

ERIC Educational Resources Information Center

Aanonson, John

1987-01-01

Compares features of online public access catalogs (OPACs) at six British universities: (1) Cambridge; (2) Hull; (3) Newcastle; (4) Surrey; (5) Sussex; and (6) York. Results of keyword subject searches on two topics performed on each of the OPACs are reported and compared. Six references are listed. (MES)

Catalog Use Studies--Since the Introduction of Online Interactive Catalogs: Impact on Design for Subject Access.

ERIC Educational Resources Information Center

Cochrane, Pauline A.; Markey, Karen

1983-01-01

This review of the transition from library card catalogs to online public access catalogs (OPAC) (1981-1982) discusses methods employed by online catalog use studies (self-administered questionnaires, OPAC transaction logs, focused-group interviews, feature analysis, online search and retrieval experiments) and new directions for OPAC research…

Dialogue with an OPAC: How Visionary Was Swanson in 1964?

ERIC Educational Resources Information Center

Su, Shiao-Feng

1994-01-01

Traces the development of online public access catalogs (OPACs) and compares what has occurred with a 1964 article that outlined recommendations for a future card catalog. Subject access is emphasized, including Library of Congress Subject Headings, expansion of OPACs, user-friendly interfaces, new technologies, and current visions of the future…

Relativistic opacities for astrophysical applications

DOE PAGES

Fontes, Christopher John; Fryer, Christopher Lee; Hungerford, Aimee L.; ...

2015-06-29

Here, we report on the use of the Los Alamos suite of relativistic atomic physics codes to generate radiative opacities for the modeling of astrophysically relevant plasmas under local thermodynamic equilibrium (LTE) conditions. The atomic structure calculations are carried out in fine-structure detail, including full configuration interaction. Three example applications are considered: iron opacities at conditions relevant to the base of the solar convection zone, nickel opacities for the modeling of stellar envelopes, and samarium opacities for the modeling of light curves produced by neutron star mergers. In the first two examples, comparisons are made between opacities that are generatedmore » with the fully and semi-relativistic capabilities in the Los Alamos suite of codes. As expected for these highly charged, iron-peak ions, the two methods produce reasonably similar results, providing confidence that the numerical methods have been correctly implemented. However, discrepancies greater than 10% are observed for nickel and investigated in detail. In the final application, the relativistic capability is used in a preliminary investigation of the complicated absorption spectrum associated with cold lanthanide elements.« less

Atmospheric Modeling of the Martian Polar Regions: One Mars Year of CRISM EPF Observations of the South Pole

NASA Astrophysics Data System (ADS)

Brown, A. J.; Wolff, M. J.

2009-03-01

We have used CRISM Emission Phase Function gimballed observations to investigate atmospheric dust/ice opacity and surface albedo in the south polar region for the first Mars year of MRO operations. This covers the MY28 "dust event" and cap recession.

Limits of Pattern Discrimination in Human Vision.

DTIC Science & Technology

1988-01-01

viewed with Nomarski differential interference microscopy at a level just vitreal to the ellipsoid-myoid junction. Positions of the cone centers were...using laser interferometry" 3. Chander Samy "Rod and cone areas as a function of retinal eccentricity" 4. Zachary Klett "Lens opacity and interferometric

New Generation of Los Alamos Opacity Tables

NASA Astrophysics Data System (ADS)

Colgan, James; Kilcrease, D. P.; Magee, N. H.; Sherrill, M. E.; Abdallah, J.; Hakel, P.; Fontes, C. J.; Guzik, J. A.; Mussack, K. A.

2016-05-01

We present a new generation of Los Alamos OPLIB opacity tables that have been computed using the ATOMIC code. Our tables have been calculated for all 30 elements from hydrogen through zinc and are publicly available through our website. In this poster we discuss the details of the calculations that underpin the new opacity tables. We also show several recent applications of the use of our opacity tables to solar modeling and other astrophysical applications. In particular, we demonstrate that use of the new opacities improves the agreement between solar models and helioseismology, but does not fully resolve the long-standing `solar abundance' problem. The Los Alamos National Laboratory is operated by Los Alamos National Security, LLC for the National Nuclear Security Administration of the U.S. Department of Energy under Contract No. DE-AC5206NA25396.

Electrolysis for corneal opacities in a young patient with superficial variant of granular corneal dystrophy (Reis-Bücklers corneal dystrophy).

PubMed

Kamoi, Mizuka; Mashima, Yukihiko; Kawashima, Motoko; Tsubota, Kazuo

2005-06-01

To report the efficacy of electrolysis as a treatment of corneal opacities in a young patient with the superficial variant of granular corneal dystrophy. Interventional case report. An 11-year-old boy presented with subepithelial opacities in both eyes. His visual acuity was 0.2 in the left eye; he received corneal electrolysis under topical anesthesia. The electrolysis, which required only 5 minutes, resulted in the disappearance of the subepithelial opacities. His visual acuity improved to 0.4 on the next day and was 1.0 eight months later. The corneal curvature and thickness were not altered by the electrolysis. Corneal electrolysis proved to be an effective treatment for subepithelial opacities, and we recommend electrolysis as an effective and simple treatment for young patients with SGCD.

HELIOS-R: An Ultrafast, Open-Source Retrieval Code For Exoplanetary Atmosphere Characterization

NASA Astrophysics Data System (ADS)

LAVIE, Baptiste

2015-12-01

Atmospheric retrieval is a growing, new approach in the theory of exoplanet atmosphere characterization. Unlike self-consistent modeling it allows us to fully explore the parameter space, as well as the degeneracies between the parameters using a Bayesian framework. We present HELIOS-R, a very fast retrieving code written in Python and optimized for GPU computation. Once it is ready, HELIOS-R will be the first open-source atmospheric retrieval code accessible to the exoplanet community. As the new generation of direct imaging instruments (SPHERE, GPI) have started to gather data, the first version of HELIOS-R focuses on emission spectra. We use a 1D two-stream forward model for computing fluxes and couple it to an analytical temperature-pressure profile that is constructed to be in radiative equilibrium. We use our ultra-fast opacity calculator HELIOS-K (also open-source) to compute the opacities of CO2, H2O, CO and CH4 from the HITEMP database. We test both opacity sampling (which is typically used by other workers) and the method of k-distributions. Using this setup, we compute a grid of synthetic spectra and temperature-pressure profiles, which is then explored using a nested sampling algorithm. By focusing on model selection (Occam’s razor) through the explicit computation of the Bayesian evidence, nested sampling allows us to deal with current sparse data as well as upcoming high-resolution observations. Once the best model is selected, HELIOS-R provides posterior distributions of the parameters. As a test for our code we studied HR8799 system and compared our results with the previous analysis of Lee, Heng & Irwin (2013), which used the proprietary NEMESIS retrieval code. HELIOS-R and HELIOS-K are part of the set of open-source community codes we named the Exoclimes Simulation Platform (www.exoclime.org).

68 Ga-PSMA-PET/CT for the evaluation of pulmonary metastases and opacities in patients with prostate cancer.

PubMed

Damjanovic, Jonathan; Janssen, Jan-Carlo; Furth, Christian; Diederichs, Gerd; Walter, Thula; Amthauer, Holger; Makowski, Marcus R

2018-05-16

The purpose of this study was to investigate the imaging properties of pulmonary metastases and benign opacities in 68 Ga-PSMA positron emission tomography (PET) in patients with prostate cancer (PC). 68 Ga-PSMA-PET/CT scans of 739 PC patients available in our database were evaluated retrospectively for lung metastases and non-solid focal pulmonary opacities. Maximum standardized uptake values (SUV max ) were assessed by two- and three-dimensional regions of interest (2D/3D ROI). Additionally CT features of the lesions, such as location, morphology and size were identified. Ninety-one pulmonary metastases and fourteen opacities were identified in 34 PC patients. In total, 66 PSMA-positive (72.5%) and 25 PSMA-negative (27.5%) metastases were identified. The mean SUV max of pulmonary opacities was 2.2±0.7 in 2D ROI and 2.4±0.8 in 3D ROI. The mean SUV max of PSMA-positive pulmonary metastases was 4.5±2.7 in 2D ROI and in 4.7±2.9 in 3D ROI; this was significantly higher than the SUV max of pulmonary opacities in both 2D and 3D ROI (p<0.001). The mean SUV max of PSMA-negative metastases was 1.0±0.5 in 2D ROI and 1.0±0.4 in 3D ROI, and significantly lower than that of the pulmonary opacities (p<0.001). A significant (p<0.05) weak linear correlation between size and 3D SUV max in lung metastases (ρ Spearman =0.207) was found. Based on the SUV max in 68 Ga-PSMA-PET alone, it was not possible to differentiate between pulmonary metastases and pulmonary opacities. The majority of lung metastases highly overexpressed PSMA, while a relevant number of metastases were PSMA-negative. Pulmonary opacities demonstrated a moderate tracer uptake, significantly lower than PSMA-positive lung metastases, yet significantly higher than PSMA-negative metastases.

Preliminary results of aerosols' properties studied with EPF measurements from the SPICAM/UV instrument

NASA Astrophysics Data System (ADS)

Willame, Yannick; Carine Vandaele, Ann; Depiesse, Cedric; Gillotay, Didier; Kochenova, Svetlana; Montmessin, Franck

2013-04-01

Aerosols on Mars have an important impact on the radiative transfer properties of its atmosphere. Today their spectral properties and therefore their interaction with UV radiation are only poorly known. Improving the radiative transfer modeling requires a better knowledge of their characteristics, in particular of their opacity, phase function and single scattering albedo. Part of such information can be accessed by using EPF observations. The SPICAM instrument on board of the Mars-Express satellite is a 2 channel spectrometer. One channel operates in the ultraviolet (118-320 nm) and the second one in the infrared (1.0-1.7μm). SPICAM has been orbiting around the red planet since 2003 and has thus provided a large set of data. The instrument is capable of measuring under different geometries (nadir, limb, occultation) and one of them, called EPF (Emission Phase Function), can be a tool to study aerosols' properties. We have developed a new retrieval algorithm for nadir measurements based on the radiative transfer model LIDORT. This new code performs simulations of spectra taking into account gas absorption, surface reflection and scattering by aerosols and gases. The retrieval method, based on the optimal estimation, allows us up to now to deduce the ozone column density, the aerosols' optical depth and the surface albedo (with fixed wavelength dependencies). We are developing our model further in order to better study the aerosols' characteristics using EPF observations, which consist in looking at the same point on the planet while the satellite moves along the orbit. As the attempt to study all the aerosols' properties simultaneously was not convincing, we started studying their opacity and the influence of its altitude distribution with the other characteristics fixed. We will present preliminary results of our study on aerosols' properties using EPF data from SPICAM.

Preliminary results of aerosols' properties studied with EPF measurements from the SPICAM/UV instrument

NASA Astrophysics Data System (ADS)

Willame, Y.; Vandaele, A.-C.; Depiesse, C.; Gillotay, D.; Kochenova, S.; Montmessin, F.

2012-04-01

Aerosols on Mars have an important impact on the radiative transfer properties of its atmosphere. Today their spectral properties and therefore their interaction with UV radiation are only poorly known. Improving the radiative transfer modeling requires a better knowledge of their characteristics, in particular of their opacity, phase function and single scattering albedo. We will show that such information can be accessed by using EPF observations. The SPICAM instrument on board of the Mars-Express satellite is a 2 channel spectrometer. One channel operates in the ultraviolet (118-320 nm) and the second one in the infrared (1.0-1.7μm). SPICAM has been orbiting around the red planet since 2003 and has thus provided a large set of data. The instrument is capable of measuring under different geometries (nadir, limb, occultation) and one of them, called EPF (Emission Phase Function), is a practical tool to study aerosols' properties. We have developed a new retrieval algorithm for nadir measurements based on the radiative transfer model LIDORT. This new code performs simulations of spectra taking into account gas absorption, surface reflection and scattering by aerosols and gases. The retrieval method, based on the optimal estimation, allows us up to now to deduce the ozone column density, the aerosols' optical depth and the surface albedo (with fixed wavelength dependencies). We are developing our model further in order to better study the aerosols' characteristics using EPF observations, which consist in looking at the same point on the planet while the satellite moves along the orbit. As the attempt to study all the aerosols' properties simultaneously was not convincing, we will start with studying their opacity and its altitude distribution with the other characteristics fixed. We will present preliminary results of our study on aerosols' properties and their wavelength dependencies, using EPF data. The method will be illustrated by investigating SPICAM observations obtained in EPF mode.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Inada, G.J.; Hall, C.W.

Results are reported from ophthalmologic observations carried out on residents of Nagasaki and Hiroshima and exposed to radiation from an atomic explosion. Very significant statistical test results indicate that lenticular opacities observed have definite relationship to ionizing radiation exposure distance from the hypocenter (exposure distance in this instance is used as a relative index of radiation dosage received). Exposure to ionizing radiation does increase the incidence of lenticular changes indicative of ionizing radiation (definite opacities, polychrome posterior capsular roughening, excessive cortical opacities unexplained and, especially, the polychrome posterior capsular plaques). No appreciable differences in opacities by sex or loss ofmore » visual acuity were observed.« less

Monochromatic, Rosseland mean, and Planck mean opacity routine

NASA Astrophysics Data System (ADS)

Semenov, D.

2006-11-01

Several FORTRAN77 codes were developed to compute frequency-dependent, Rosseland and Planck mean opacities of gas and dust in protoplanetary disks. The opacities can be computed for an ensemble of dust grains having various compositions (ices, silicates, organics, etc), sizes, topologies (homogeneous/composite aggregates, homogeneous/layered/composite spheres, etc.), porosities, and dust-to-gas ratio. Several examples are available. In addition, a very fast opacity routine to be used in modeling of the radiative transfer in hydro simulations of disks is available upon request (10^8 routine calls require about 30s on Pentium 4 3.0GHz).

Measuring the radiative properties of astrophysical matter using the Z X-ray source

NASA Astrophysics Data System (ADS)

Bailey, James; ZAPP Team

2017-06-01

The Z Astrophysical Plasma Properties (ZAPP) collaboration is staging Z experiments that simultaneously investigate multiple topics in radiative properties of hot dense matter. The four astrophysics questions presently guiding this research are: 1) Why can’t we predict the location of the convection zone base in the Sun?; 2) How does radiation transport affect spectrum formation in accretion-powered objects?; 3) Why doesn’t spectral fitting provide the correct properties for White Dwarfs?; and 4) Why can’t we predict the heating and charge state distribution in photoionized plasmas? Recent progress using Z, the most energetic x-ray source on earth, to address these questions will be described. We emphasize the first two topics. Opacity models are an essential ingredient of stellar models and are highly sophisticated, but laboratory opacity tests have only now become possible at the conditions existing inside stars. Our opacity research emphasizes measuring iron at conditions relevant to the base of the solar convection zone, where the electron temperature and density are believed to be 190 eV and 9x1022 e/cc, respectively. The results exhibit large disagreements between iron opacity measurements and models and ongoing research is aimed at testing hypotheses for this discrepancy. The second project is motivated by the fact that emission lines from L-shell ions are not observed from iron in black hole accretion disks, but are observed from silicon in x-ray binaries. These disparate observations may be explained by differences in the radiation transport within the plasmas, but models for the spectral line formation and transport in photoionized plasmas have never been tested. We investigate photoionized silicon plasmas using absorption spectroscopy to infer the plasma conditions and emission spectroscopy to determine the dependence of spectral emission on plasma column density.++Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy under contract DE-AC04-94AL85000.

Life cycle cost evaluation of the digital opacity compliance system.

PubMed

McFarland, Michael J; Palmer, Glenn R; Olivas, Arthur C

2010-01-01

The US Environmental Protection Agency (EPA) has established EPA Reference Method 9 (Method 9) as the preferred enforcement approach for verifying compliance with federal visible opacity standards. While Method 9 has an extensive history of successful employment, reliance on human observers to quantify visible emissions is inherently subjective, a characteristic that exposes Method 9 results to claims of inaccuracy, bias and, in some cases, outright fraud. The Digital Opacity Compliance System (DOCS), which employs commercial-off-the-shelf digital photography coupled with simple computer processing, is a new approach for quantifying visible opacity. The DOCS technology has been previously demonstrated to meet and, in many cases, surpass the Method 9 accuracy and reliability standards (McFarland et al., 2006). Beyond its performance relative to Method 9, DOCS provides a permanent visual record of opacity, a vital feature in legal compliance challenges. In recent DOCS field testing, the opacity analysis of two hundred and forty one (241) regulated air emissions from the following industrial processes: 1) industrial scrubbers, 2) emergency generators, 3) asphalt paving, 4) steel production and 5) incineration indicated that Method 9 and DOCS were statistically equivalent at the 99% confidence level. However, a life cycle cost analysis demonstrated that implementation of DOCS could potentially save a facility $15,732 per trained opacity observer compared to utilization of Method 9. Copyright 2009 Elsevier Ltd. All rights reserved.

Dependent lung opacity at thin-section CT: evaluation by spirometrically-gated CT of the influence of lung volume.

PubMed

Lee, Ki Nam; Yoon, Seong Kuk; Sohn, Choon Hee; Choi, Pil Jo; Webb, W Richard

2002-01-01

To evaluate the influence of lung volume on dependent lung opacity seen at thin-section CT. In thirteen healthy volunteers, thin-section CT scans were performed at three levels (upper, mid, and lower portion of the lung) and at different lung volumes (10, 30, 50, and 100% vital capacity), using spirometric gated CT. Using a three-point scale, two radiologists determined whether dependent opacity was present, and estimated its degree. Regional lung attenuation at a level 2 cm above the diaphragm was determined using semiautomatic segmentation, and the diameter of a branch of the right lower posterior basal segmental artery was measured at each different vital capacity. At all three anatomic levels, dependent opacity occurred significantly more often at lower vital capacities (10, 30%) than at 100% vital capacity (p = 0.001). Visually estimated dependent opacity was significantly related to regional lung attenuation (p < 0.0001), which in dependent areas progressively increased as vital capacity decreased (p < 0.0001). The presence of dependent opacity and regional lung attenuation of a dependent area correlated significantly with increased diameter of a segmental arterial branch (r = 0.493 and p = 0.0002; r = 0.486 and p = 0.0003, respectively). Visual estimation and CT measurements of dependent opacity obtained by semiautomatic segmentation are significantly influenced by lung volume and are related to vascular diameter.

Thermal Electrons in Gamma-Ray Burst Afterglows

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ressler, Sean M.; Laskar, Tanmoy

2017-08-20

To date, nearly all multi-wavelength modeling of long-duration γ -ray bursts has ignored synchrotron radiation from the significant population of electrons expected to pass the shock without acceleration into a power-law distribution. We investigate the effect of including the contribution of thermal, non-accelerated electrons to synchrotron absorption and emission in the standard afterglow model, and show that these thermal electrons provide an additional source of opacity to synchrotron self-absorption, and yield an additional emission component at higher energies. The extra opacity results in an increase in the synchrotron self-absorption frequency by factors of 10–100 for fiducial parameters. The nature ofmore » the additional emission depends on the details of the thermal population, but is generally observed to yield a spectral peak in the optical brighter than radiation from the nonthermal population by similar factors a few seconds after the burst, remaining detectable at millimeter and radio frequencies several days later.« less

77 FR 8160 - Quality Assurance Requirements for Continuous Opacity Monitoring Systems at Stationary Sources

Federal Register 2010, 2011, 2012, 2013, 2014

2012-02-14

..., glass windows (uncoated or anti-reflection coated, but with no curvature), lenses with mounts where such... requirements must I meet if I use a substitute opacity monitor? In the event that your certified opacity... the above in the maintenance log or in other appropriate permanently maintained records. 10.7 When do...

The Searching Behavior of Remote Users: A Study of One Online Public Access Catalog (OPAC).

ERIC Educational Resources Information Center

Kalin, Sally W.

1991-01-01

Describes a study that was conducted to determine whether the searching behavior of remote users of LIAS (Library Information Access System), Pennsylvania State University's online public access catalog (OPAC), differed from those using the OPAC within the library. Differences in search strategies and in user satisfaction are discussed. (eight…

Open-Source Tools for Enhancing Full-Text Searching of OPACs: Use of Koha, Greenstone and Fedora

ERIC Educational Resources Information Center

Anuradha, K. T.; Sivakaminathan, R.; Kumar, P. Arun

2011-01-01

Purpose: There are many library automation packages available as open-source software, comprising two modules: staff-client module and online public access catalogue (OPAC). Although the OPAC of these library automation packages provides advanced features of searching and retrieval of bibliographic records, none of them facilitate full-text…

Fac-Back-OPAC: An Open Source Interface to Your Library System

ERIC Educational Resources Information Center

Beccaria, Mike; Scott, Dan

2007-01-01

The new Fac-Back-OPAC (a faceted backup OPAC) is built on code that was originally developed by Casey Durfee in February 2007. It represents the convergence of two prominent trends in library tools: the decoupling of discovery tools from the traditional integrated library system (ILS) and the use of readily available open source components to…

On the methane opacity for Uranus and Neptune.

NASA Technical Reports Server (NTRS)

Trafton, L.

1972-01-01

The contribution of methane to the thermal opacity in the atmospheres of Uranus and Neptune is shown to be negligible. The relevance of this finding lies in the importance of knowing all the sources of thermal opacity to include in models of these atmospheres, for only then may it be possible to deduce their atmospheric structure and composition correctly.

Bibliographic Displays in OPACs and Web Catalogs: How Well Do They Comply with Display Guidelines?

ERIC Educational Resources Information Center

Cherry, Joan M.

1998-01-01

Evaluation of data from assessments of full bibliographic displays in academic library OPACs (online public access catalogs) and World Wide Web catalogs against a checklist of desirable features found that OPAC displays scored 58% and Web displays scored 60%. Discusses weaknesses, focusing on those found in the majority of the displays…

Asymptotic expansions of the kernel functions for line formation with continuous absorption

NASA Technical Reports Server (NTRS)

Hummer, D. G.

1991-01-01

Asymptotic expressions are obtained for the kernel functions M2(tau, alpha, beta) and K2(tau, alpha, beta) appearing in the theory of line formation with complete redistribution over a Voigt profile with damping parameter a, in the presence of a source of continuous opacity parameterized by beta. For a greater than 0, each coefficient in the asymptotic series is expressed as the product of analytic functions of a and eta. For Doppler broadening, only the leading term can be evaluated analytically.

Radiographic abnormalities in relation to total dust exposure at a bauxite refinery and alumina-based chemical products plant.

PubMed

Townsend, M C; Sussman, N B; Enterline, P E; Morgan, W K; Belk, H D; Dinman, B D

1988-07-01

A cross-sectional study of 788 male employees of an aluminum production company examined the relationship of radiographic abnormalities to smoking and dust exposure from the mining and refining of bauxite to alumina. Among the aluminas produced were low temperature range transitional forms. The present analyses were limited to nonsmokers and current smokers. Two National Institute of Occupational Safety and Health (NIOSH)-certified "B" readers interpreted the radiographs. The predominant radiographic abnormalities noted were scanty, small, irregular opacities in the lower zones of profusion 0/1 to 1/1. Rounded opacities were rare. Among nonsmokers with low dust exposures, the prevalence of opacities greater than or equal to 1/0 showed no trend with increasing age and duration of exposure, suggesting no relationship between age and prevalence of opacities of Category 1 or more in this cohort (p greater than 0.10). Nonsmokers who had accumulated higher dust exposures showed a trend of increasing prevalence of opacities with increasing duration, suggesting an effect of occupational exposure at higher cumulative exposure levels (p less than 0.05). In most exposure categories, smokers exceeded nonsmokers in their prevalence of opacities greater than or equal to 1/0; the overall prevalence among smokers being 12 and 11% according to Readers A and B, respectively, compared with 4% in nonsmokers (p less than 0.01). In conclusion, 7 to 8% of aluminum workers in this cohort had radiographic findings of scanty, small, irregular opacities, the prevalence of which was increased among smokers (p less than 0.01). There was a moderate increase in the prevalence of opacities with increasing tenure in nonsmokers with high cumulative exposures (p less than 0.05).

A new in vitro method to evaluate radio-opacity of endodontic sealers.

PubMed

Malka, V B; Hochscheidt, G L; Larentis, N L; Grecca, F S; Fontanella, V R C; Kopper, P M P

2015-01-01

To evaluate a new method for assessing the radio-opacity of endodontic sealers and to compare radio-opacity values with a well-established standard method. The sealers evaluated in this study were AH Plus(®) (Dentsply DeTrey GmbH, Konstanz, Germany), Endo CPM Sealer (EGEO SRL, Buenos Aires, Argentina) and MTA Fillapex(®) (Angelus Dental Products Industry S/A, Londrina, Parana, Brazil). Two methods were used to evaluate radio-opacity: (D) standard discs and (S) a tissue simulator. For (D), ten standard discs were prepared for each sealer and were radiographed using Digora(®) phosphor storage plates (Soredex; Orion Corporation, Helsinki, Finland), alongside an aluminium stepwedge. For (S), polyethylene tubes filled with sealer (n = 10 for each) were radiographed inside the simulator as described. The digital images were analysed using Adobe Photoshop(®) software v. 10.0 (Adobe Systems, San Jose, CA). To compare the radio-opacity among the sealers, the data were analysed by ANOVA and Tukey's test, and to compare methods, they were analysed by the Mann-Whitney U test. To compare the data obtained from dentin and sealers in method (S), Student's paired t-test was used (=0.05). In both methods, the sealers showed significant differences, according to the following decreasing order: AH Plus, MTA Fillapex and Endo CPM. In (D), MTA Fillapex and Endo CPM showed less radio-opacity than aluminium. For all of the materials, the radio-opacity was higher in (S) than in (D). Compared with dentin, all of the materials were more radio-opaque. The comparison of the two assessment methods for sealer radio-opacity testing validated the use of a tissue simulator block.

A new in vitro method to evaluate radio-opacity of endodontic sealers

PubMed Central

Malka, V B; Hochscheidt, G L; Larentis, N L; Grecca, F S; Kopper, P M P

2015-01-01

Objectives: To evaluate a new method for assessing the radio-opacity of endodontic sealers and to compare radio-opacity values with a well-established standard method. Methods: The sealers evaluated in this study were AH Plus® (Dentsply DeTrey GmbH, Konstanz, Germany), Endo CPM Sealer (EGEO SRL, Buenos Aires, Argentina) and MTA Fillapex® (Angelus Dental Products Industry S/A, Londrina, Parana, Brazil). Two methods were used to evaluate radio-opacity: (D) standard discs and (S) a tissue simulator. For (D), ten standard discs were prepared for each sealer and were radiographed using Digora® phosphor storage plates (Soredex; Orion Corporation, Helsinki, Finland), alongside an aluminium stepwedge. For (S), polyethylene tubes filled with sealer (n = 10 for each) were radiographed inside the simulator as described. The digital images were analysed using Adobe Photoshop® software v. 10.0 (Adobe Systems, San Jose, CA). To compare the radio-opacity among the sealers, the data were analysed by ANOVA and Tukey's test, and to compare methods, they were analysed by the Mann–Whitney U test. To compare the data obtained from dentin and sealers in method (S), Student's paired t-test was used (=0.05). Results: In both methods, the sealers showed significant differences, according to the following decreasing order: AH Plus, MTA Fillapex and Endo CPM. In (D), MTA Fillapex and Endo CPM showed less radio-opacity than aluminium. For all of the materials, the radio-opacity was higher in (S) than in (D). Compared with dentin, all of the materials were more radio-opaque. Conclusions: The comparison of the two assessment methods for sealer radio-opacity testing validated the use of a tissue simulator block. PMID:25651275

Radiation Transport for Explosive Outflows: Opacity Regrouping

NASA Astrophysics Data System (ADS)

Wollaeger, Ryan T.; van Rossum, Daniel R.

2014-10-01

Implicit Monte Carlo (IMC) and Discrete Diffusion Monte Carlo (DDMC) are methods used to stochastically solve the radiative transport and diffusion equations, respectively. These methods combine into a hybrid transport-diffusion method we refer to as IMC-DDMC. We explore a multigroup IMC-DDMC scheme that in DDMC, combines frequency groups with sufficient optical thickness. We term this procedure "opacity regrouping." Opacity regrouping has previously been applied to IMC-DDMC calculations for problems in which the dependence of the opacity on frequency is monotonic. We generalize opacity regrouping to non-contiguous groups and implement this in SuperNu, a code designed to do radiation transport in high-velocity outflows with non-monotonic opacities. We find that regrouping of non-contiguous opacity groups generally improves the speed of IMC-DDMC radiation transport. We present an asymptotic analysis that informs the nature of the Doppler shift in DDMC groups and summarize the derivation of the Gentile-Fleck factor for modified IMC-DDMC. We test SuperNu using numerical experiments including a quasi-manufactured analytic solution, a simple 10 group problem, and the W7 problem for Type Ia supernovae. We find that opacity regrouping is necessary to make our IMC-DDMC implementation feasible for the W7 problem and possibly Type Ia supernova simulations in general. We compare the bolometric light curves and spectra produced by the SuperNu and PHOENIX radiation transport codes for the W7 problem. The overall shape of the bolometric light curves are in good agreement, as are the spectra and their evolution with time. However, for the numerical specifications we considered, we find that the peak luminosity of the light curve calculated using SuperNu is ~10% less than that calculated using PHOENIX.

Comparative pulsation calculations with OP and OPAL opacities

NASA Technical Reports Server (NTRS)

Kanbur, Shashi M.; Simon, Norman R.

1994-01-01

Comparative linear nonadiabatic pulsation calculations are presented using the OPAL and Opacity Project opacities. The two sets of opacities include effects due to intermediate coupling and fine structure as well as new abundances. We used two mass luminosity (M-L) relations, one standard (BIT), and one employing substantial convective core overshoot (COV). The two sets of opacities cannot be differentiated on the basis of the stellar pulsation calculations presented here. The BIT relation can model the beat and bump Cepheids with masses between 4 and 7 solar mass, while if the overshoot relation is used, masses between 2 and 6 solar mass are required. In the RR Lyrae regime, we find the inferred masses of globular cluster RRd stars to be little influenced by the choice of OPAL or OP. Finally, the limited modeling we have done is not able to constrain the Cepheid M-L relation based upon period ratios observed in the beat and bump stars.

Lanthanide/Actinide Opacities

NASA Astrophysics Data System (ADS)

Hungerford, Aimee; Fontes, Christopher J.

2018-06-01

Gravitational wave observations benefit from accompanying electromagnetic signals in order to accurately determine the sky positions of the sources. The ejecta of neutron star mergers are expected to produce such electromagnetic transients, called macronovae (e.g. the recent and unprecedented observation of GW170817). Characteristics of the ejecta include large velocity gradients and the presence of heavy r-process elements, which pose significant challenges to the accurate calculation of radiative opacities and radiation transport. Opacities include a dense forest of bound-bound features arising from near-neutral lanthanide and actinide elements. Here we present an overview of current theoretical opacity determinations that are used by neutron star merger light curve modelers. We will touch on atomic physics and plasma modeling codes that are used to generate these opacities, as well as the limited body of laboratory experiments that may serve as points of validation for these complex atomic physics calculations.

Mars Global Surveyor TES Results: Observations of Water Ice Clouds

NASA Technical Reports Server (NTRS)

Pearl, John C.; Smith, M. D.; Conrath, B. J.; Bandfield, J. L.; Christensen, P. R.

1999-01-01

On July 31, 1999, Mars Global Surveyor completed its first martian year in orbit. During this time, the Thermal Emission Spectrometer (TES) experiment gathered extensive data on water ice clouds. We report here on three types of martian clouds. 1) Martian southern summer has long been characterized as the season when the most severe dust storms occur. It is now apparent that northern spring/summer is characterized as a time of substantial low latitude ice clouds [1]. TES observations beginning in the northern summer (Lsubs=107) show a well developed cloud belt between 10S and 30N latitude; 12 micron opacities were typically 0.15. This system decreased dramatically after Lsubs= 130. Thereafter, remnants were most persistent over the Tharsis ridge. 2) Clouds associated with major orographic features follow a different pattern [2]. Clouds of this type were present prior to the regional Noachis dust storm of 1997. They disappeared with the onset of the storm, but reappeared rather quickly following its decay. Typical infrared opacities were near 0.5. 3) Extensive, very thin clouds are also widespread [3]. Found at high altitudes (above 35 km), their opacities are typically a few hundredths. At times, such as in northern spring, these clouds are limited in their northern extent only by the southern edge of the polar vortex. We describe the distribution, infrared optical properties, and seasonal trends of these systems during the first martian year of TES operations.

Tile-based parallel coordinates and its application in financial visualization

NASA Astrophysics Data System (ADS)

Alsakran, Jamal; Zhao, Ye; Zhao, Xinlei

2010-01-01

Parallel coordinates technique has been widely used in information visualization applications and it has achieved great success in visualizing multivariate data and perceiving their trends. Nevertheless, visual clutter usually weakens or even diminishes its ability when the data size increases. In this paper, we first propose a tile-based parallel coordinates, where the plotting area is divided into rectangular tiles. Each tile stores an intersection density that counts the total number of polylines intersecting with that tile. Consequently, the intersection density is mapped to optical attributes, such as color and opacity, by interactive transfer functions. The method visualizes the polylines efficiently and informatively in accordance with the density distribution, and thus, reduces visual cluttering and promotes knowledge discovery. The interactivity of our method allows the user to instantaneously manipulate the tiles distribution and the transfer functions. Specifically, the classic parallel coordinates rendering is a special case of our method when each tile represents only one pixel. A case study on a real world data set, U.S. stock mutual fund data of year 2006, is presented to show the capability of our method in visually analyzing financial data. The presented visual analysis is conducted by an expert in the domain of finance. Our method gains the support from professionals in the finance field, they embrace it as a potential investment analysis tool for mutual fund managers, financial planners, and investors.

HP2 survey. III. The California Molecular Cloud: A sleeping giant revisited

NASA Astrophysics Data System (ADS)

Lada, Charles J.; Lewis, John A.; Lombardi, Marco; Alves, João

2017-10-01

We present new high resolution and dynamic range dust column density and temperature maps of the California Molecular Cloud derived from a combination of Planck and Herschel dust-emission maps, and 2MASS NIR dust-extinction maps. We used these data to determine the ratio of the 2.2 μm extinction coefficient to the 850 μm opacity and found the value to be close to that found in similar studies of the Orion B and Perseus clouds but higher than that characterizing the Orion A cloud, indicating that variations in the fundamental optical properties of dust may exist between local clouds. We show that over a wide range of extinction, the column density probability distribution function (pdf) of the cloud can be well described by a simple power law (I.e., PDFN ∝ AK -n) with an index (n = 4.0 ± 0.1) that represents a steeper decline with AK than found (n ≈ 3) in similar studies of the Orion and Perseus clouds. Using only the protostellar population of the cloud and our extinction maps we investigate the Schmidt relation, that is, the relation between the protostellar surface density, Σ∗, and extinction, AK, within the cloud. We show that Σ∗ is directly proportional to the ratio of the protostellar and cloud pdfs, I.e., PDF∗(AK)/PDFN(AK). We use the cumulative distribution of protostars to infer the functional forms for both Σ∗ and PDF∗. We find that Σ∗ is best described by two power-law functions. At extinctions AK ≲ 2.5 mag, Σ∗ ∝ AK β with β = 3.3 while at higher extinctions β = 2.5, both values steeper than those (≈2) found in other local giant molecular clouds (GMCs). We find that PDF∗ is a declining function of extinction also best described by two power-laws whose behavior mirrors that of Σ∗. Our observations suggest that variations both in the slope of the Schmidt relation and in the sizes of the protostellar populations between GMCs are largely driven by variations in the slope, n, of PDFN(AK). This confirms earlier studies suggesting that cloud structure plays a major role in setting the global star formation rates in GMCs HP2 (Herschel-Planck-2MASS) survey is a continuation of the series originally entitled "Herschel-Planck dust opacity and column density maps" (Lombardi et al. 2014, Zari et al. 2016).The reduced Herschel and Planck map and the column density and temperature maps are available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/606/A100

Student User Preferences for Features of Next-Generation OPACs: A Case Study of University of Sheffield International Students

ERIC Educational Resources Information Center

Tam, Winnie; Cox, Andrew M.; Bussey, Andy

2009-01-01

Purpose: The purpose of this paper is to identify the features that international student users prefer for next generation OPACs. Design/methodology/approach: A total of 16 international students of the University of Sheffield were interviewed in July 2008 to explore their preferences among potential features in next generation OPACs. A…

Interannual Variability of Dust and Ice in the Mars Atmosphere: Comparison of MRO Mars Climate Sounder Retrievals with MGS-TES Limb Sounding Retrievals

NASA Technical Reports Server (NTRS)

Shirley, J. H.; McConnochie, T. H.; Kleinbohl, A.; Schofield, J. T.; Kass, D.; Heavens, N. G.; Benson, J.; McCleese, D. J.

2011-01-01

Dust and ice play important roles in Martian atmospheric dynamics on all time scales. Dust loading in particular exerts an important control on atmospheric temperatures and thereby on the strength of the atmospheric circulation in any given year. We present the first comparisons of MGS-TES aerosol opacity profiles with MRO-MCS aerosol opacity profiles. While the differences in vertical resolution are significant (a factor of 2), we find good agreement at particular seasons between nightside zonal average dust opacity profiles from the two instruments. Derived water ice opacities are likewise similar but show greater variability.

OPserver: opacities and radiative accelerations on demand

NASA Astrophysics Data System (ADS)

Mendoza, C.; González, J.; Seaton, M. J.; Buerger, P.; Bellorín, A.; Meléndez, M.; Rodríguez, L. S.; Delahaye, F.; Zeippen, C. J.; Palacios, E.; Pradhan, A. K.

2009-05-01

We report on developments carried out within the Opacity Project (OP) to upgrade atomic database services to comply with e-infrastructure requirements. We give a detailed description of an interactive, online server for astrophysical opacities, referred to as OPserver, to be used in sophisticated stellar modelling where Rosseland mean opacities and radiative accelerations are computed at every depth point and each evolution cycle. This is crucial, for instance, in chemically peculiar stars and in the exploitation of the new asteroseismological data. OPserver, downloadable with the new OPCD_3.0 release from the Centre de Données Astronomiques de Strasbourg, France, computes mean opacities and radiative data for arbitrary chemical mixtures from the OP monochromatic opacities. It is essentially a client-server network restructuring and optimization of the suite of codes included in the earlier OPCD_2.0 release. The server can be installed locally or, alternatively, accessed remotely from the Ohio Supercomputer Center, Columbus, Ohio, USA. The client is an interactive web page or a subroutine library that can be linked to the user code. The suitability of this scheme in grid computing environments is emphasized, and its extension to other atomic database services for astrophysical purposes is discussed.

Constraining the Dust Opacity Law in Three Small and Isolated Molecular Clouds

DOE Office of Scientific and Technical Information (OSTI.GOV)

Webb, K. A.; Thanjavur, K.; Di Francesco, J.

Density profiles of isolated cores derived from thermal dust continuum emission rely on models of dust properties, such as mass opacity, that are poorly constrained. With complementary measures from near-infrared extinction maps, we can assess the reliability of commonly used dust models. In this work, we compare Herschel -derived maps of the optical depth with equivalent maps derived from CFHT WIRCAM near-infrared observations for three isolated cores: CB 68, L 429, and L 1552. We assess the dust opacities provided from four models: OH1a, OH5a, Orm1, and Orm4. Although the consistency of the models differs between the three sources, themore » results suggest that the optical properties of dust in the envelopes of the cores are best described by either silicate and bare graphite grains (e.g., Orm1) or carbonaceous grains with some coagulation and either thin or no ice mantles (e.g., OH5a). None of the models, however, individually produced the most consistent optical depth maps for every source. The results suggest that either the dust in the cores is not well-described by any one dust property model, the application of the dust models cannot be extended beyond the very center of the cores, or more complex SED fitting functions are necessary.« less

Inference of dust opacities for the 1977 Martian great dust storms from Viking Lander 1 pressure data

NASA Technical Reports Server (NTRS)

Zurek, R. W.

1981-01-01

The tidal heating components for the dusty Martian atmosphere are computed based on dust optical parameters estimated from Viking Lander imaging data, and used to compute the variation of the tidal surface pressure components at the Viking Lander sites as a function of season and the total vertical extinction optical depth of the atmosphere. An atmospheric tidal model is used which is based on the inviscid, hydrostatic primitive equations linearized about a motionless basic state the temperature of which varies only with height, and the profiles of the tidal forcing components are computed using a delta-Eddington approximation to the radiative transfer equations. Comparison of the model results with the observed variations of surface pressure and overhead dust opacity at the Viking Lander 1 site reveal that the dust opacities and optical parameters derived from imaging data are roughly representative of the global dust haze necessary to reproduce the observed surface pressure amplitudes, with the exception of the model-inferred asymmetry parameter, which is smaller during the onset of a great storm. The observed preferential enhancement of the semidiurnal tide with respect to the diurnal tide during dust storm onset is shown to be due primarily to the elevation of the tidal heating source in a very dusty atmosphere.

NIMS Observes the Structure and Composition of Jupiter Clouds

NASA Image and Video Library

1998-03-26

With the NIMS instrument high quality observations are being obtained from all parts of Jupiter. The images in the upper panel are taken at a wavelength of 4.8 microns. At this wavelength thermal radiation from about 100 km deep below the visible cloud deck is escaping, allowing us to study the deep atmospheric region. The overlying cloud deck absorbs a part of the radiation, but there are places where it is thin and more radiation can escape. These are called hot spot regions. Many hotspots regions occur in a zone between the equator and 15 degrees north latitude, the North Equatorial Belt (NEB), but thermal radiation is seen from much of the planet. The uniqueness of NIMS is that it is capable of observing the same spatial region at a maximum of 408 different wavelengths between 0.7 and 5.2 micron simultaneously. Every picture element (pixel) contains a spectrum of up to 408 wavelengths. The gases that compose the atmosphere leave there traces in the spectra. In this particular case, 48 wavelengths were available between 4.6 and 5.2 micron, and we see spectral signatures of water, ammonia, and phosphine. Also, the total amount of radiation is determined by the amount of overlying cloud, characterized by the cloud opacity. By means of model calculations, we can determine the amount of water and the cloud opacity for each individual spectrum. The amount ammonia and phosphine is more difficult to obtain because its influence on the spectra is weaker. The results of these calculations are shown in the form of maps in the next two panels. With NIMS, we can now have a detailed look at the spatial distribution of the water and ammonia amounts and the cloud opacity in the atmosphere. Not all the pixels from the observations have good spectra, so for some data points no reliable determination of the water and cloud opacity could be made. We find that the atmosphere is extremely dry in, and close to, the hot spot, with relative humidities between 0.02 % and 10 %, with the dryest places being inside the hot spot. This corroborates the in-situ Galileo Entry Probe measurements. The Probe entered the atmosphere, on December 5 1995, in a hot spot region. Whereas the Probe obtained only a very localized snapshot, with NIMS we can do observations of larger areas and over longer periods. The spatial distribution of water is more complex than expected. More detailed investigations will be necessary to fully understand these results. http://photojournal.jpl.nasa.gov/catalog/PIA01224

A DETERMINATION OF THE INTERGALACTIC REDSHIFT-DEPENDENT ULTRAVIOLET-OPTICAL-NIR PHOTON DENSITY USING DEEP GALAXY SURVEY DATA AND THE GAMMA-RAY OPACITY OF THE UNIVERSE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stecker, Floyd W.; Malkan, Matthew A.; Scully, Sean T., E-mail: Floyd.W.Stecker@nasa.gov, E-mail: malkan@astro.ucla.edu, E-mail: scullyst@jmu.edu

2012-12-20

We calculate the intensity and photon spectrum of the intergalactic background light (IBL) as a function of redshift using an approach based on observational data obtained in many different wavelength bands from local to deep galaxy surveys. This allows us to obtain an empirical determination of the IBL and to quantify its observationally based uncertainties. Using our results on the IBL, we then place 68% confidence upper and lower limits on the opacity of the universe to {gamma}-rays, free of the theoretical assumptions that were needed for past calculations. We compare our results with measurements of the extragalactic background lightmore » and upper limits obtained from observations made by the Fermi Gamma-ray Space Telescope.« less

Effects of injection pressure and injection timing to exhaust gas opacity for a conventional indirect diesel engine

NASA Astrophysics Data System (ADS)

Budiman, Agus; Majid, Akmal Irfan; Pambayun, Nirmala Adhi Yoga; Yuswono, Lilik Chaerul; Sukoco

2016-06-01

In relation to pollution control and environmental friendliness, the quality of exhaust gas from diesel engine needs to be considered. The influences of injection pressure and timing to exhaust gas opacity were investigated. A series of experiments were conducted in a one-cylinder conventional diesel engine with a naturally aspirated system and indirect injection. The default specification of injection pressure was 120 kg/cm2. To investigate the injection pressure, the engine speed was retained on 1000 rpm with pressure variations from 80 to 215 kg/cm2. On the other hand, the various injection timing (8, 10, 12, 16 degrees before TDC point and exact 18 degrees before TDC point) were used to determine their effects to exhaust gas opacity. In this case, the engine speed was varied from 1000 to 2400 rpm. The injector tester was used to measure injection pressure whereas the exhaust gas opacity was determined by the smoke meter. Those data were also statistically analyzed by product moment correlation. As the results, the injection pressure of diesel engine had a non-significant positive correlation to the exhaust gas opacity with r = 0.113 and p > 5 %. Injection pressure should be adjusted to the specification listed on the diesel engine as if it was too high or too low will lead to the higher opacity. Moreover, there was a significant positive correlation between injection timing and the exhaust gas opacity in all engine speeds.

Using a Web OPAC To Deliver Digital Collections.

ERIC Educational Resources Information Center

Mathias, Eileen C.

2003-01-01

Describes a major digital imaging project just completed at the Ewell Sale Steward Library of the Academy of Natural Sciences (Philadelphia, PA). Discusses options that were considered for Web delivery of images and text, and reasons for choosing Innovative Interfaces, Inc.'s image management function. Describes the data entry process and reviews…

Higher-order aberrations of lenticular opacities.

PubMed

Sachdev, Nisha; Ormonde, Susan E; Sherwin, Trevor; McGhee, Charles N J

2004-08-01

To measure and quantify higher-order aberrations induced by different types of lenticular opacities. Department of Ophthalmology, University of Auckland, and Department of Ophthalmology, Auckland Public Hospital, Auckland, New Zealand. Patients with lenticular opacities were recruited from outpatient clinics of a major tertiary referral center for ophthalmology. Patients were included if they had clinically evident, mild to moderate lenticular opacity with no coexisting ocular pathology. Patients were examined using standard preoperative techniques with additional assessment by wavefront aberrometry (Zywave, Bausch & Lomb) and Scheimpflug photography (EAS-1000, Nidek). For comparison, 20 eyes of 10 subjects with no lenticular opacity (control group) were recruited and assessed in an identical manner. Thirty persons were recruited and 40 eyes assessed, 20 with lenticular opacities. Ten eyes had predominantly cortical opacification, and 10 had mainly nuclear opacification. In eyes with predominantly cortical opacification, the mean logMAR uncorrected visual acuity (UCVA) was 0.5 +/- 0.2 (SD) (6/18 Snellen equivalent) and the mean logMAR best spectacle-corrected visual acuity (BSCVA), 0.2 +/- 0.2 (6/9). Analysis of aberrometry data for a 6.0 mm pupil in this group revealed an increase in coma of cosine phase (Z(3), P =.06) and tetrafoil of cosine phase (Z(4), P =.07) compared to eyes in the control group. Eyes with predominantly nuclear opacification had a mean logMAR UCVA of 0.7 +/- 0.2 (6/30) and a logMAR BSCVA of 0.4 +/- 0.2 (6/15). Aberrometry data for this cohort for a 6.0 mm pupil showed a statistically greater amount of spherical aberration (Z(4)(0), P =.001) and tetrafoil of cosine phase (Z(4), P =.005; Z(4)(-4), P =.004). This pilot study suggests that different types of early lenticular opacities induce different wavefront aberration profiles. Predominantly cortical opacification produced an increase in coma and nuclear opacification induced an increase in spherical aberration compared to eyes without opacities. Both types of lenticular opacities also induced a higher amount of tetrafoil. This could explain the significant visual symptoms in patients with early cataract and relatively good high-contrast Snellen acuity.

Types, Sizes, Shapes and Distributions of Mars Ice and Dust Aerosols from the MGS TES Emission Phase Function Observations

NASA Astrophysics Data System (ADS)

Clancy, R. T.; Wolff, M. J.; Christensen, P. R.

2001-12-01

A full Mars year (1999-2001) of emission phase function (EPF observations from Mars Global Surveyor (MGS) Thermal Emission Spectrometer (TES) provide the most complete study of Mars dust and ice aerosol properties to date. TES visible (solar band average) and infrared spectral (6-30 micron, 10 invcm res) EPF sequences are analyzed self-consistently with detailed multiple scattering radiative transfer (RT) codes to obtain first-time seasonal/latitudinal distributions of aerosol visible optical depths, particle sizes, and single scattering phase functions. As a consequence of the combined angular and wavelength coverage, we are able to define two distinct ice cloud types at 45S-45N latitudes on Mars. Type 1 ice clouds exhibit small particle sizes (1-2 micron radii), as well as a broad, deep minimum in side scattering indicative of aligned ice grains (see Wolff et al., 2001). Type 1 ice aerosols are most prevalent in the southern hemisphere during Mars aphelion, but also appear more widely distributed in season and latitude as topographic and high altitude (above 20 km) ice hazes. Type 2 ice clouds exhibit larger particle sizes (2-4 microns) and a much narrower side-scattering minimum, indicative of poorer grain alignment or a change in particle shape relative to the type 1 ice clouds (see Wolff et al., 2001). Type 2 ice clouds appear most prominently in the northern subtropical aphelion cloud belt, where relatively low altitudes of water vapor saturation (10 km) coincide with strong advective transport (Clancy et al., 1996). Retrieved dust particle radii of 1.5-1.8 micron are consistent with Pathfinder (Tomasko et al., 1999) and recent Viking/Mariner 9 reanalyses (e.g., size distribution B of Clancy et al., 1995). Detailed spectral modeling of the solar passband also implies agreement of EPF-derived dust single scattering albedos (ssa) with the ssa results from Tomasko et al.(table 8 therein). Spatial and seasonal changes in the dust ssa (0.92-0.95, solar band average) and phase functions suggest possible dust property variations, but may also be a consequence of variable high altitude ice hazes. The annual variations of both dust and ice clouds at 45S-45N latitudes are predominately orbital rather than seasonal in character and have shown close repeatability during the portions of first two Mars years observed by MGS (i.e., prior to the July 2001 global dust storm which began at Ls=185, a most striking departure from the previous two Mars years observed). Minimum visible dust opacities of 0.05-0.10 occur at southern latitudes in aphelion, maximum dust opacities of 1.0-1.5 at northern latitudes after Ls=200 (and greater than 3 in the 2001 global dust storm). Type 2 ice clouds abruptly disappear at Ls=145, as does the widespread occurrence of type 1 clouds in the southern hemisphere. Dust loading in the southern hemisphere increases at this time, but does not do so in the northern hemisphere. A comparison of dust solar band to thermal infrared optical depth ratios also provides strong evidence for non-uniform vertical mixing of the dust loading. A large fraction of the dust column (20-50 percent) appears to be concentrated in the lower boundary layer of the Mars atmosphere, particularly during conditions of low-to-moderate dust loading.

Cosmic Reionization on Computers: Properties of the Post-reionization IGM

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gnedin, Nickolay Y.; Becker, George D.; Fan, Xiaohui

Here, we present a comparison between several observational tests of the post-reionization IGM and the numerical simulations of reionization completed under the Cosmic Reionization On Computers (CROC) project. The CROC simulations match the gap distribution reasonably well, and also provide a good match for the distribution of peak heights, but there is a notable lack of wide peaks in the simulated spectra and the flux PDFs are poorly matched in the narrow redshift interval 5.5 < z < 5.7, with the match at other redshifts being significantly better, albeit not exact. Both discrepancies are related: simulations show more opacity thanmore » the data.« less

Cosmic Reionization on Computers: Properties of the Post-reionization IGM

DOE PAGES

Gnedin, Nickolay Y.; Becker, George D.; Fan, Xiaohui

2017-05-19

Here, we present a comparison between several observational tests of the post-reionization IGM and the numerical simulations of reionization completed under the Cosmic Reionization On Computers (CROC) project. The CROC simulations match the gap distribution reasonably well, and also provide a good match for the distribution of peak heights, but there is a notable lack of wide peaks in the simulated spectra and the flux PDFs are poorly matched in the narrow redshift interval 5.5 < z < 5.7, with the match at other redshifts being significantly better, albeit not exact. Both discrepancies are related: simulations show more opacity thanmore » the data.« less

Jupiter's para-H2 distribution from SOFIA/FORCAST and Voyager/IRIS 17-37 μm spectroscopy

NASA Astrophysics Data System (ADS)

Fletcher, Leigh N.; de Pater, I.; Reach, W. T.; Wong, M.; Orton, G. S.; Irwin, P. G. J.; Gehrz, R. D.

2017-04-01

Spatially resolved maps of Jupiter's far-infrared 17-37 μm hydrogen-helium collision-induced spectrum were acquired by the FORCAST instrument on the Stratospheric Observatory for Infrared Astronomy (SOFIA) in May 2014. Spectral scans in two grisms covered the broad S(0) and S(1) absorption lines, in addition to contextual imaging in eight broad-band filters (5-37 μm) with spatial resolutions of 2-4″. The spectra were inverted to map the zonal-mean temperature and para-H2 distribution (fp, the fraction of the para spin isomer with respect to the ortho spin isomer) in Jupiter's upper troposphere (the 100-700 mbar range). We compared these to a reanalysis of Voyager-1 and -2 IRIS spectra covering the same spectral range. Tropospheric temperature contrasts match those identified by Voyager in 1979, within the limits of temporal variability consistent with previous investigations. Para-H2 increases from equator to pole, with low-fp air at the equator representing sub-equilibrium conditions (i.e., less para-H2 than expected from thermal equilibration), and high-fp air and possible super-equilibrium at higher latitudes. In particular, we confirm the continued presence of a region of high-fp air at high northern latitudes discovered by Voyager/IRIS, and an asymmetry with generally higher fp in the north than in the south. Far-IR aerosol opacity is not required to fit the data, but cannot be completely ruled out. We note that existing collision-induced absorption databases lack opacity from (H2)2 dimers, leading to under-prediction of the absorption near the S(0) and S(1) peaks. There appears to be no spatial correlation between para-H2 and tropospheric ammonia, phosphine and cloud opacity derived from Voyager/IRIS at mid-infrared wavelengths (7-15 μm). We note, however, that para-H2 tracks the similar latitudinal distribution of aerosols within Jupiter's upper tropospheric and stratospheric hazes observed in reflected sunlight, suggesting that catalysis of hydrogen equilibration within the hazes (and not the main clouds) may govern the equator-to-pole gradient, with conditions closer to equilibrium at higher latitudes. This gradient is superimposed onto smaller-scale variations associated with regional advection of para-H2 at the equator and poles.

Opacplot2: Enabling tabulated EoS and opacity compatibility for HEDLP simulations with the FLASH code

NASA Astrophysics Data System (ADS)

Laune, Jordan; Tzeferacos, Petros; Feister, Scott; Fatenejad, Milad; Yurchak, Roman; Flocke, Norbert; Weide, Klaus; Lamb, Donald

2017-10-01

Thermodynamic and opacity properties of materials are necessary to accurately simulate laser-driven laboratory experiments. Such data are compiled in tabular format since the thermodynamic range that needs to be covered cannot be described with one single theoretical model. Moreover, tabulated data can be made available prior to runtime, reducing both compute cost and code complexity. This approach is employed by the FLASH code. Equation of state (EoS) and opacity data comes in various formats, matrix-layouts, and file-structures. We discuss recent developments on opacplot2, an open-source Python module that manipulates tabulated EoS and opacity data. We present software that builds upon opacplot2 and enables easy-to-use conversion of different table formats into the IONMIX format, the native tabular input used by FLASH. Our work enables FLASH users to take advantage of a wider range of accurate EoS and opacity tables in simulating HELP experiments at the National Laser User Facilities.

The effect of the Mihalas, Hummer, and Daeppen equation of state and the molecular opacity on the standard solar model

NASA Technical Reports Server (NTRS)

Kim, Y.-C.; Demarque, P.; Guenther, D. B.

1991-01-01

Improvements to the Yale Rotating Stellar Evolution Code (YREC) by incorporating the Mihalas-Hummer-Daeppen equation of state, an improved opacity interpolation routine, and the effects of molecular opacities, calculated at Los Alamos, have been made. the effect of each of the improvements on the standard solar model has been tested independently by computing the corresponding solar nonradial oscillation frequencies. According to these tests, the Mihalas-Hummer-Daeppen equation of state has very little effect on the model's low l p-mode oscillation spectrum compared to the model using the existing analytical equation of state implemented in YREC. On the other hand, the molecular opacity does improve the model's oscillation spectrum. The effect of molecular opacity on the computed solar oscillation frequencies is much larger than that of the Mihalas-Hummer-Daeppen equation of state. together, the two improvements to the physics reduce the discrepancy with observations by 10 microHz for the low l modes.

In vitro evaluation of UV opacity potential of Aloe vera L. gel from different germplasms.

PubMed

Kumar, M Shyam; Datta, P K; Dutta Gupta, S

2009-04-01

In this study, lyophilized crude and methanolic extracts of aloe gel from different germplasms (S24, RM, TN, OR, and RJN) of Aloe vera L. were tested for their ultraviolet (UV) opacity potential. UV absorption profiles, sun protection factor (SPF), and percentage blocking of UVA and UVB were considered to test UV opacity potential. Both the extracts showed UV absorption and followed the same path in the wavelength range of 250-400 nm in all the germplasms. Methanolic extract showed a stronger absorptivity than the crude lyophilized extract. Among the tested germplasms, maximum UV opacity property with a SPF of 9.97% and 79.12% UVB blocking was obtained with RJN, whereas a poor response was evident in TN with a SPF of 1.37% and 28.5% UVB blocking at 4 mg/ml methanolic extract. To our knowledge the present work for the first time documents UV opacity properties of A. vera L. gel and opens up new vistas in Aloe gel characterization.

Constraints on cosmic silicates

NASA Astrophysics Data System (ADS)

Ossenkopf, V.; Henning, Th.; Mathis, J. S.

1992-08-01

Observational determinations of opacities of circumstellar silicates, relative to the peak value near 10 microns, are used to estimate the optical constants n and k, the real and imaginary parts of the index of refraction. Circumstellar dust is modified by processing within the interstellar medium. This leads to higher band strengths and a somewhat larger ratio of the opacities at the 18 and 10-micron peaks, compared with circumstellar silicates. By using an effective-medium theory, we calculate the effects of small spherical inclusions of various materials (various oxides, sulfides, carbides, amorphous carbon, and metallic iron) upon silicate opacities. Some of these can increase the absorption coefficient k in the 2-8 micron region appreciably, as is needed to reconcile laboratory silicate opacities with observations of both the interstellar medium and envelopes around late-type stars. We give tables of two sets of optical constants for warm oxygen-deficient and cool oxygen-rich silicates, representative for circumstellar and interstellar silicates. The required opacity in the 2-8 micron region is provided by iron and magnetite.

An asymptotic preserving unified gas kinetic scheme for frequency-dependent radiative transfer equations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sun, Wenjun, E-mail: sun_wenjun@iapcm.ac.cn; Jiang, Song, E-mail: jiang@iapcm.ac.cn; Xu, Kun, E-mail: makxu@ust.hk

This paper presents an extension of previous work (Sun et al., 2015 [22]) of the unified gas kinetic scheme (UGKS) for the gray radiative transfer equations to the frequency-dependent (multi-group) radiative transfer system. Different from the gray radiative transfer equations, where the optical opacity is only a function of local material temperature, the simulation of frequency-dependent radiative transfer is associated with additional difficulties from the frequency-dependent opacity. For the multiple frequency radiation, the opacity depends on both the spatial location and the frequency. For example, the opacity is typically a decreasing function of frequency. At the same spatial region themore » transport physics can be optically thick for the low frequency photons, and optically thin for high frequency ones. Therefore, the optical thickness is not a simple function of space location. In this paper, the UGKS for frequency-dependent radiative system is developed. The UGKS is a finite volume method and the transport physics is modeled according to the ratio of the cell size to the photon's frequency-dependent mean free path. When the cell size is much larger than the photon's mean free path, a diffusion solution for such a frequency radiation will be obtained. On the other hand, when the cell size is much smaller than the photon's mean free path, a free transport mechanism will be recovered. In the regime between the above two limits, with the variation of the ratio between the local cell size and photon's mean free path, the UGKS provides a smooth transition in the physical and frequency space to capture the corresponding transport physics accurately. The seemingly straightforward extension of the UGKS from the gray to multiple frequency radiation system is due to its intrinsic consistent multiple scale transport modeling, but it still involves lots of work to properly discretize the multiple groups in order to design an asymptotic preserving (AP) scheme in all regimes. The current scheme is tested in a few frequency-dependent radiation problems, and the results are compared with the solutions from the well-defined implicit Monte Carlo (IMC) method. The UGKS is much more efficient than IMC, and the computational times of both schemes for all test cases are listed. The UGKS seems to be the first discrete ordinate method (DOM) for the accurate capturing of multiple frequency radiative transport physics from ballistic particle motion to the diffusive wave propagation.« less

Opacity from two-photon processes

DOE PAGES

More, Richard M.; Hansen, Stephanie B.; Nagayama, Taisuke

2017-07-22

Here, the recent iron opacity measurements performed at Sandia National Laboratory by Bailey and collaborators have raised questions about the completeness of the physical models normally used to understand partially ionized hot dense plasmas. We describe calculations of two-photon absorption, which is a candidate for the observed extra opacity. Our calculations do not yet match the experiments but show that the two-photon absorption process is strong enough to require careful consideration.

On measurements of Effective Residual Ink Concentration (ERIC) of deinked papers using Kubelka-Munk theory

Treesearch

D.W. Vahey; J.Y. Zhu; C.J. Houtman

2006-01-01

The measurement of effective residual ink concentration (ERIC) in recycled papers depends on their opacity. For opacity less than 97.0%, the method is based on application of the Kubelka-Munk theory to diffuse reflection from papers measured once with a black backing and again with a thick backing of the same papers. At opacities above 97.0%, the two reflection values...

Eye Lens Opacities Among Physicians Occupationally Exposed to Ionizing Radiation.

PubMed

Auvinen, Anssi; Kivelä, Tero; Heinävaara, Sirpa; Mrena, Samy

2015-08-01

We compared the frequency of lens opacities among physicians with and without occupational exposure to ionizing radiation, and estimated dose-response between cumulative dose and opacities. We conducted ophthalmologic examinations of 21 physicians with occupational exposure to radiation and 16 unexposed physicians. Information on cumulative radiation doses (mean 111 mSv) was based on dosimeter readings recorded in a national database on occupational exposures. Lens changes were evaluated using the Lens Opacities Classification System II, with an emphasis on posterior subcapsular (PSC) and cortical changes. Among the exposed physicians, the prevalences of cortical and PSC changes were both 11% (3/21), and the corresponding frequencies in the unexposed group were 44% (n = 7) and 6% (n = 1). For dose-response analysis, the data were pooled with 29 exposed physicians from our previous study. No association of either type of lens changes with cumulative recorded dose was observed. Our findings do not indicate an increased frequency of lens opacities in physicians with occupational exposure to ionizing radiation. However, the subjects in this study have received relatively low doses and therefore the results do not exclude small increases in lens opacities or contradict the studies reporting increases among interventional cardiologists with materially higher cumulative doses. © The Author 2015. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.

Atomic structure considerations for the low-temperature opacity of Sn

DOE PAGES

Colgan, J.; Kilcrease, D. P.; Abdallah, J.; ...

2017-03-31

Here, we have begun a preliminary investigation into the opacity of Sn at low temperatures (< 50 eV). The emissivity and opacity of Sn is a crucial factor in determining the utility of Sn in EUV lithography, with numerous industrial implications. To this end, we have been exploring the accuracy of some approximations used in opacity models for the relevant ion stages of Sn (neutral through ~ 18 times ionized). We also find that the use of intermediate-coupling, as compared to full configuration-interaction, is not adequate to obtain accurate line positions of the important bound-bound transitions in Sn. One requiresmore » full configuration-interaction to properly describe the strong mixing between the various n=4 sub-shells that give rise to the Δn= 0 transitions that dominate the opacity spectrum at low temperatures. Furthermore, since calculations that include full configuration-interaction for large numbers of configurations quickly become computationally prohibitive, we have explored hybrid calculations, in which full configuration-interaction is retained for the most important transitions, while intermediate-coupling is employed for all other transitions. After extensive exploration of the atomic structure properties, local-thermodynamic-equilibrium (LTE) opacities are generated using the ATOMIC code at selected temperatures and densities and compared to experiment.« less

Atomic structure considerations for the low-temperature opacity of Sn

DOE Office of Scientific and Technical Information (OSTI.GOV)

Colgan, J.; Kilcrease, D. P.; Abdallah, J.

Here, we have begun a preliminary investigation into the opacity of Sn at low temperatures (< 50 eV). The emissivity and opacity of Sn is a crucial factor in determining the utility of Sn in EUV lithography, with numerous industrial implications. To this end, we have been exploring the accuracy of some approximations used in opacity models for the relevant ion stages of Sn (neutral through ~ 18 times ionized). We also find that the use of intermediate-coupling, as compared to full configuration-interaction, is not adequate to obtain accurate line positions of the important bound-bound transitions in Sn. One requiresmore » full configuration-interaction to properly describe the strong mixing between the various n=4 sub-shells that give rise to the Δn= 0 transitions that dominate the opacity spectrum at low temperatures. Furthermore, since calculations that include full configuration-interaction for large numbers of configurations quickly become computationally prohibitive, we have explored hybrid calculations, in which full configuration-interaction is retained for the most important transitions, while intermediate-coupling is employed for all other transitions. After extensive exploration of the atomic structure properties, local-thermodynamic-equilibrium (LTE) opacities are generated using the ATOMIC code at selected temperatures and densities and compared to experiment.« less

Io's SO2 Atmosphere Viewed in Silhouette by Jupiter Lyman-α

NASA Astrophysics Data System (ADS)

Retherford, Kurt D.; Roth, Lorenz; Feaga, Lori M.; Becker, Tracy M.; Tsang, Constantine; Jessup, Kandis-Lea; Grava, Cesare

2016-10-01

We report a new technique for mapping Io's SO2 vapor distribution. Hubble's Space Telescope Imaging Spectrograph (STIS) instrument observed Io during four Jupiter transit events to obtain medium resolution far-UV spectral images near the Lyman-α wavelength of 121.6 nm. Jupiter's bright Lyman-α dayglow provides a background light source for opacity measurements, much like during a stellar occultation or transiting exoplanet event. Peaks in the photoabsorption cross-sections for sulfur dioxide occur near 122 nm, with resulting absorptions raising the altitude where a tangential line of sight opacity of tau=1 is detected up to resolvable distances above the disk. This method of measuring column densities along lines of sight above the limb complements Lyman-α reflectance imaging and other methods for measuring Io's SO2 gas. For example, interpretation of Io's surface reflected components at far-UV wavelengths is complicated by SO2 frost features being correlated with regions of known volcanic outgassing activity, while Jupiter's Lyman-α dayglow provides a more spatially uniform background light source. Initial examination of these near-terminator limb observations with STIS confirms the findings from previous Lyman-α disk reflectance imaging using STIS's G140L mode (e.g., Feldman et al., GRL, 2000; Feaga et al. 2009) that Io's polar SO2 density is roughly an order of magnitude lower than found at the equator. As Strobel & Wolven (2001) described it, Io appears to wear its dayside atmosphere as "a belt" around the equator. We describe detailed simulations, now underway, that incorporate the STIS point spread function and consideration of additional attenuation by atmospheric hydrogen atoms, which are produced by charge exchange reactions between magnetospheric protons and Io's atmosphere.

HELIOS: An Open-source, GPU-accelerated Radiative Transfer Code for Self-consistent Exoplanetary Atmospheres

NASA Astrophysics Data System (ADS)

Malik, Matej; Grosheintz, Luc; Mendonça, João M.; Grimm, Simon L.; Lavie, Baptiste; Kitzmann, Daniel; Tsai, Shang-Min; Burrows, Adam; Kreidberg, Laura; Bedell, Megan; Bean, Jacob L.; Stevenson, Kevin B.; Heng, Kevin

2017-02-01

We present the open-source radiative transfer code named HELIOS, which is constructed for studying exoplanetary atmospheres. In its initial version, the model atmospheres of HELIOS are one-dimensional and plane-parallel, and the equation of radiative transfer is solved in the two-stream approximation with nonisotropic scattering. A small set of the main infrared absorbers is employed, computed with the opacity calculator HELIOS-K and combined using a correlated-k approximation. The molecular abundances originate from validated analytical formulae for equilibrium chemistry. We compare HELIOS with the work of Miller-Ricci & Fortney using a model of GJ 1214b, and perform several tests, where we find: model atmospheres with single-temperature layers struggle to converge to radiative equilibrium; k-distribution tables constructed with ≳ 0.01 cm-1 resolution in the opacity function (≲ {10}3 points per wavenumber bin) may result in errors ≳ 1%-10% in the synthetic spectra; and a diffusivity factor of 2 approximates well the exact radiative transfer solution in the limit of pure absorption. We construct “null-hypothesis” models (chemical equilibrium, radiative equilibrium, and solar elemental abundances) for six hot Jupiters. We find that the dayside emission spectra of HD 189733b and WASP-43b are consistent with the null hypothesis, while the latter consistently underpredicts the observed fluxes of WASP-8b, WASP-12b, WASP-14b, and WASP-33b. We demonstrate that our results are somewhat insensitive to the choice of stellar models (blackbody, Kurucz, or PHOENIX) and metallicity, but are strongly affected by higher carbon-to-oxygen ratios. The code is publicly available as part of the Exoclimes Simulation Platform (exoclime.net).

GLOBAL MODELING OF NEBULAE WITH PARTICLE GROWTH, DRIFT, AND EVAPORATION FRONTS. I. METHODOLOGY AND TYPICAL RESULTS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Estrada, Paul R.; Cuzzi, Jeffrey N.; Morgan, Demitri A., E-mail: Paul.R.Estrada@nasa.gov

2016-02-20

We model particle growth in a turbulent, viscously evolving protoplanetary nebula, incorporating sticking, bouncing, fragmentation, and mass transfer at high speeds. We treat small particles using a moments method and large particles using a traditional histogram binning, including a probability distribution function of collisional velocities. The fragmentation strength of the particles depends on their composition (icy aggregates are stronger than silicate aggregates). The particle opacity, which controls the nebula thermal structure, evolves as particles grow and mass redistributes. While growing, particles drift radially due to nebula headwind drag. Particles of different compositions evaporate at “evaporation fronts” (EFs) where the midplanemore » temperature exceeds their respective evaporation temperatures. We track the vapor and solid phases of each component, accounting for advection and radial and vertical diffusion. We present characteristic results in evolutions lasting 2 × 10{sup 5} years. In general, (1) mass is transferred from the outer to the inner nebula in significant amounts, creating radial concentrations of solids at EFs; (2) particle sizes are limited by a combination of fragmentation, bouncing, and drift; (3) “lucky” large particles never represent a significant amount of mass; and (4) restricted radial zones just outside each EF become compositionally enriched in the associated volatiles. We point out implications for millimeter to submillimeter SEDs and the inference of nebula mass, radial banding, the role of opacity on new mechanisms for generating turbulence, the enrichment of meteorites in heavy oxygen isotopes, variable and nonsolar redox conditions, the primary accretion of silicate and icy planetesimals, and the makeup of Jupiter’s core.« less

Implicit Monte Carlo with a linear discontinuous finite element material solution and piecewise non-constant opacity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wollaeger, Ryan T.; Wollaber, Allan B.; Urbatsch, Todd J.

2016-02-23

Here, the non-linear thermal radiative-transfer equations can be solved in various ways. One popular way is the Fleck and Cummings Implicit Monte Carlo (IMC) method. The IMC method was originally formulated with piecewise-constant material properties. For domains with a coarse spatial grid and large temperature gradients, an error known as numerical teleportation may cause artificially non-causal energy propagation and consequently an inaccurate material temperature. Source tilting is a technique to reduce teleportation error by constructing sub-spatial-cell (or sub-cell) emission profiles from which IMC particles are sampled. Several source tilting schemes exist, but some allow teleportation error to persist. We examinemore » the effect of source tilting in problems with a temperature-dependent opacity. Within each cell, the opacity is evaluated continuously from a temperature profile implied by the source tilt. For IMC, this is a new approach to modeling the opacity. We find that applying both source tilting along with a source tilt-dependent opacity can introduce another dominant error that overly inhibits thermal wavefronts. We show that we can mitigate both teleportation and under-propagation errors if we discretize the temperature equation with a linear discontinuous (LD) trial space. Our method is for opacities ~ 1/T 3, but we formulate and test a slight extension for opacities ~ 1/T 3.5, where T is temperature. We find our method avoids errors that can be incurred by IMC with continuous source tilt constructions and piecewise-constant material temperature updates.« less

The influence of urban area opacity on biologically active UV-B irradiance

NASA Astrophysics Data System (ADS)

Chubarova, Nataly; Rozental', Victor

2013-04-01

The study of UV irradiance changes in urban area is an essential problem due to the significant effect of UV irradiance on human health which can be positive (vitamin D synthesis) and negative (erythema, skin cancer, eye damage). According to the results of several experiments within the Moscow megacity we studied the effects of urban area opacity on the different types of biologically active UV-B irradiance on the base of a specially developed mobile photometric complex snd additional measurements of the urban opacity by Nikon Fisheye Converter FC-E8. We analyzed both the level of erythemally-active irradiance and the UV eye damaging radiation using the broadband UVB-1 YES pyranometer calibrated against ultraviolet spectroradiometer Bentham DTM-300 of the Medical University of Innsbruck (courtesy of Dr. M.Blumthaler). In order to estimate the effects of the urban opacity the measurements were normalized on similar measurements at the Meteorological Observatory of Moscow State University with zero opacity. This ratio is defined as an urban radiative transmittance (URT). Different atmospheric conditions were considered. In cloudy conditions the effect of opacity on URT is much less than that in conditions when the sun disk is open from clouds. We revealed some spectral features in transmittance of biologically active UV-B irradiance which is characterized by higher URT variations in overcast cloudy conditions due to more intensive scattering and smaller direct solar radiation component. In the absence of cloudiness the effect of opacity was studied for open and screening solar disk conditions. We obtained much higher URT in UVB spectral region compared with that for total solar irradiance for screening solar disk conditions with a significant URT dependence on the opacity only in UVB spectral region. No URT dependence was obtained for total solar irradiance in these conditions. Some model calculations were fulfilled to match the experimental results.

Pneumoconiosis in different sectors and their differences in Turkey.

PubMed

Alıcı, Nur Şafak; Çımrın, Arif; Coşkun Beyan, Ayşe

2016-12-01

Pneumoconiosis which is one of the ancient diseases, still affects many workers throughout the world despite "existing" control programs. We add data from a single center reviewing risk factors for pneumoconiosis; evaluate functional and radiological findings in different sectors. We reviewed medical records of patients diagnosed with pneumoconiosis who were admitted to our center between the years 2013 and 2015. Several personal and occupational features, together with functional and radiologic data, were collected. 60 were young males. Twenty-four of the cases (39.3%) worked at dental technician, 24 cases (39.3%) were ceramic workers, 5 cases (8.2%) were sandblasters, 2 cases (3.3%) were welders, 3 cases (4.9%) were miners, and 3 cases (4.9%) were marble cutters. The sectors in which the exposure started at the earliest ages were dental technicians and sandblasters, while the shortest working time was in sandblasting. The dental technicians were younger than the ceramic workers at the age of diagnosis (Kruskall-Wallis p= 0.003). The exposure time of the sandblasters was significantly shorter, especially than the ceramic workers (Kruskall-Wallis p= 0.002). The cases have been referred to us with pneumoconiosis suspicion based on the radiographic findings in the PA chest roentgenogram performed during the periodic examinations at their work place; but unlike other studies, in our study, following the HRCT assessment, cases which did not present any visible pathology in the re-evaluation of their PA chest roentgenogram, but had HRCT findings have been diagnosed as pneumoconiosis. Among the 44 cases in which micro-nodules had been detected at their HRCT, 15 of them had been previously classified as profusion of small opacities 0/1 according to their PA chest roentgenogram findings. It has been seen that the HRCT findings differ among sectors. Ceramics workers and sandblasters had significantly more micro-nodules, while dental technicians had significantly more mediastinal lymphadenopathies (Chi square, p= 0.004 and p= 0.007 respectively). When the relationship between the existence of big opacities and complaints was studied, statistically significant weight loss was detected in cases which had C opacities (chi square p= 0.01). Statistically significant FEV1 decrease was observed in cases which had weight loss (independent samples t-test p= 0.046). It has been observed that when the profusion of small opacities increased, while there was no statistically significant functional status change in non-smokers, a significant functional impairment was observed in smokers. Pneumoconiosis still exists in Turkey. Even a short exposure time as 2 years can cause pneumoconiosis. Workers in different sectors had different functional, radiological properties and smoking can affect the diseases' course. There are serious limitations related to the surveillance of both the workplace environment and the employees' health in Turkey. Without institutional preventive measures, personal protection and surveillance examinations, occupational hazards will continue to cause premature deaths. Pneumoconiosis in different sectors is a prototype of uncontrolled industry in the developing world.

Relationships (II) of International Classification of High-resolution Computed Tomography for Occupational and Environmental Respiratory Diseases with ventilatory functions indices for parenchymal abnormalities.

PubMed

Tamura, Taro; Suganuma, Narufumi; Hering, Kurt G; Vehmas, Tapio; Itoh, Harumi; Akira, Masanori; Takashima, Yoshihiro; Hirano, Harukazu; Kusaka, Yukinori

2015-01-01

The International Classification of High-Resolution Computed Tomography (HRCT) for Occupational and Environmental Respiratory Diseases (ICOERD) is used to screen and diagnose respiratory illnesses. Using univariate and multivariate analysis, we investigated the relationship between subject characteristics and parenchymal abnormalities according to ICOERD, and the results of ventilatory function tests (VFT). Thirty-five patients with and 27 controls without mineral-dust exposure underwent VFT and HRCT. We recorded all subjects' occupational history for mineral dust exposure and smoking history. Experts independently assessed HRCT using the ICOERD parenchymal abnormalities (Items) grades for well-defined rounded opacities (RO), linear and/or irregular opacities (IR), and emphysema (EM). High-resolution computed tomography showed that 11 patients had RO; 15 patients, IR; and 19 patients, EM. According to the multiple regression model, age and height had significant associations with many indices ventilatory functions such as vital capacity, forced vital capacity, and forced expiratory volume in 1 s (FEV1). The EM summed grades on the upper, middle, and lower zones of the right and left lungs also had significant associations with FEV1 and the maximum mid-expiratory flow rate. The results suggest the ICOERD notation is adequate based on the good and significant multiple regression modeling of ventilatory function with the EM summed grades.

Epidemiological-environmental study of diesel bus garage workers: chronic effects of diesel exhaust on the respiratory system.

PubMed

Gamble, J; Jones, W; Minshall, S

1987-10-01

Two hundred and eighty-three (283) male diesel bus garage workers from four garages in two cities were examined to determine if there was excess chronic respiratory morbidity related to diesel exposure. The dependent variables were respiratory symptoms, radiographic interpretation for pneumoconiosis, and pulmonary function (FVC, FEV1, and flow rates). Independent variables included race, age, smoking, drinking, height, and tenure (as surrogate measure of exposure). Exposure-effect relationships within the study population showed no detectable associations of symptoms with tenure. There was an apparent association of pulmonary function and tenure. Seven workers (2.5%) had category 1 pneumoconiosis (three rounded opacities, two irregular opacities, and one with both rounded and irregular). The study population was also compared to a nonexposed "blue-collar" population. After indirect adjustment for age, race, and smoking, the study population had elevated prevalences of cough, phlegm, and wheezing, but there was no association with tenure. Dyspnea showed a dose-response trend but no apparent increase in prevalence. Mean percent predicted pulmonary function of the study population was greater than 100%, i.e., elevated above the comparison population. These data show there is an apparent effect of diesel exhaust on pulmonary function but not chest radiographs. Respiratory symptoms are high compared to "blue-collar" workers, but there is no relationship with tenure.

Silicosis and lung function decrements among female ceramic workers in Italy.

PubMed

Forastiere, Francesco; Goldsmith, David F; Sperati, Alessandra; Rapiti, Elisabetta; Miceli, Maria; Cavariani, Fulvio; Perucci, Carlo A

2002-11-01

It is well known that male ceramic workers have elevated risks of chronic silicosis. The objective of this study was to assess whether female ceramic workers also have an increased risk of silicosis and whether these women have decreased lung function related to silica exposure. Ceramic workers from Civitacastellana, Italy, were enrolled in health surveillance during the 1970s. A total of 642 women were under surveillance; a respiratory monitoring program was conducted from 1974 to 1987, with follow-up through 1991 that included annual chest radiography and measurement of lung function. Radiography findings were defined as silicosis if the chest films were > or =1/0 with small, rounded opacities. Multiple linear regression models for repeated measures (generalized estimating equations) were run to evaluate associations of forced vital capacity (FVC) and forced expiratory volume in 1 second (FEV(1)) with years of exposure and radiograph opacities. Nine cases of silicosis were identified on the basis of radiographic evidence. Silicosis risk was not associated with smoking but was related to employment before 1970 and demonstrated a dose-response gradient for years of exposure. FVC and FEV(1) both showed significant (p < 0.05) associations with duration of exposure and with positive radiography findings. The results for female ceramic workers are consistent with those for male employees regarding exposure to fibrogenic dusts.

Thermal infrared properties of Titan's stratospheric aerosol

NASA Technical Reports Server (NTRS)

Samuelson, Robert E.; Mayo, Louis A.

1991-01-01

The monotonic increase with wavenumber of stratospheric IR opacities in the north polar neighborhood of Titan, in the 250-600/cm bandpass, becomes more extreme with decreasing altitude, consistent with an opacity that is primarily dependent on a high altitude photochemical aerosol, on the one hand, but which is moderated by condensed organics at lower altitudes. Because condensates exhibit a wavenumber dependence for opacity which is the opposite of that required, it is suggested that condensed nitriles may be prominent; either of these condensates may be acceptable for sufficiently large particles. While comparisons with low-latitude data indicate no clear dependence of vertically-integrated opacity on latitude above 80 km, indications of a particle size and/or composition gradient with latitude in the lower stratosphere are noted.

Probing the interstellar dust towards the Galactic Centre: dust-scattering halo around AX J1745.6-2901

NASA Astrophysics Data System (ADS)

Jin, Chichuan; Ponti, Gabriele; Haberl, Frank; Smith, Randall

2017-07-01

AX J1745.6-2901 is an X-ray binary located at only 1.45 arcmin from Sgr A⋆, showcasing a strong X-ray dust-scattering halo. We combine Chandra and XMM-Newton observations to study the halo around this X-ray binary. Our study shows two major thick dust layers along the line of sight (LOS) towards AX J1745.6-2901. The LOS position and NH of these two layers depend on the dust grain models with different grain size distributions and abundances. But for all the 19 dust grain models considered, dust layer-1 is consistently found to be within a fractional distance of 0.11 (mean value: 0.05) to AX J1745.6-2901 and contains only (19-34) per cent (mean value: 26 per cent) of the total LOS dust. The remaining dust is contained in layer-2, which is distributed from the Earth up to a mean fractional distance of 0.64. A significant separation between the two layers is found for all the dust grain models, with a mean fractional distance of 0.31. Besides, an extended wing component is discovered in the halo, which implies a higher fraction of dust grains with typical sizes ≲590 Å than considered in current dust grain models. Assuming AX J1745.6-2901 is 8 kpc away, dust layer-2 would be located in the Galactic disc several kpc away from the Galactic Centre (GC). The dust scattering halo biases the observed spectrum of AX J1745.6-2901 severely in both spectral shape and flux, and also introduces a strong dependence on the size of the instrumental point spread function and the source extraction region. We build xspec models to account for this spectral bias, which allow us to recover the intrinsic spectrum of AX J1745.6-2901 free from dust-scattering opacity. If dust layer-2 also intervenes along the LOS to Sgr A⋆ and other nearby GC sources, a significant spectral correction for the dust-scattering opacity would be necessary for all these GC sources.

Temporal evolution of UV opacity and dust particle size at Gale Crater from MSL/REMS measurements

NASA Astrophysics Data System (ADS)

Vicente-Retortillo, Álvaro; Martinez, German; Renno, Nilton O.; Lemmon, Mark T.; Mason, Emily; De la Torre, Manuel

2016-10-01

A better characterization of the size, radiative properties and temporal variability of suspended dust in the Martian atmosphere is necessary to improve our understanding of the current climate of Mars. The REMS UV sensor onboard the Mars Science Laboratory (MSL) Curiosity rover has performed ground-based measurements of solar radiation in six different UV spectral bands for the first time on Mars.We developed a novel technique to retrieve dust opacity and particle size from REMS UV measurements. We use the electrical output current (TELRDR products) of the six photodiodes and the ancillary data (ADR products) to avoid inconsistencies found in the processed data (units of W/m2) when the solar zenith angle is above 30°. In addition, we use TELRDR and ADR data only in events during which the Sun is temporally blocked by the rover's masthead or mast to mitigate uncertainties associated to the degradation of the sensor due to the deposition of dust on it. Then we use a radiative transfer model with updated dust properties based on the Monte-Carlo method to retrieve the dust opacity and particle size.We find that the seasonal trend of UV opacity is consistent with opacity values at 880 nm derived from Mastcam images of the Sun, with annual maximum values in spring and in summer and minimum values in winter. The interannual variability is low, with two local maxima in mid-spring and mid-summer. Finally, dust particle size also varies throughout the year with typical values of the effective radius in the range between 0.5 and 2 μm. These variations in particle size occur in a similar way to those in dust opacity; the smallest sizes are found when the opacity values are the lowest.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wollaeger, Ryan T.; Van Rossum, Daniel R., E-mail: wollaeger@wisc.edu, E-mail: daan@flash.uchicago.edu

Implicit Monte Carlo (IMC) and Discrete Diffusion Monte Carlo (DDMC) are methods used to stochastically solve the radiative transport and diffusion equations, respectively. These methods combine into a hybrid transport-diffusion method we refer to as IMC-DDMC. We explore a multigroup IMC-DDMC scheme that in DDMC, combines frequency groups with sufficient optical thickness. We term this procedure ''opacity regrouping''. Opacity regrouping has previously been applied to IMC-DDMC calculations for problems in which the dependence of the opacity on frequency is monotonic. We generalize opacity regrouping to non-contiguous groups and implement this in SuperNu, a code designed to do radiation transport inmore » high-velocity outflows with non-monotonic opacities. We find that regrouping of non-contiguous opacity groups generally improves the speed of IMC-DDMC radiation transport. We present an asymptotic analysis that informs the nature of the Doppler shift in DDMC groups and summarize the derivation of the Gentile-Fleck factor for modified IMC-DDMC. We test SuperNu using numerical experiments including a quasi-manufactured analytic solution, a simple 10 group problem, and the W7 problem for Type Ia supernovae. We find that opacity regrouping is necessary to make our IMC-DDMC implementation feasible for the W7 problem and possibly Type Ia supernova simulations in general. We compare the bolometric light curves and spectra produced by the SuperNu and PHOENIX radiation transport codes for the W7 problem. The overall shape of the bolometric light curves are in good agreement, as are the spectra and their evolution with time. However, for the numerical specifications we considered, we find that the peak luminosity of the light curve calculated using SuperNu is ∼10% less than that calculated using PHOENIX.« less

Measuring the opacity of stellar interior matter in terrestrial laboratories

NASA Astrophysics Data System (ADS)

Bailey, James

2015-11-01

How does energy propagate from the core to the surface of the Sun, where it emerges to warm the Earth? Nearly a century ago Eddington recognized that the attenuation of radiation by stellar matter controls the internal structure of stars like the sun. Opacities for high energy density (HED) matter are challenging to calculate because accurate and complete descriptions of the energy levels, populations, and plasma effects such as continuum lowering and line broadening are needed for partially ionized atoms. This requires approximations, in part because billions of bound-bound and bound-free electronic transitions can contribute to the opacity. Opacity calculations, however, have never been benchmarked against laboratory measurements at stellar interior conditions. Laboratory opacity measurements were limited in the past by the challenges of creating and diagnosing sufficiently large and uniform samples at the extreme conditions found inside stars. In research conducted over more than 10 years, we developed an experimental platform on the Z facility and measured wavelength-resolved iron opacity at electron temperatures Te = 156-195 eV and densities ne = 0.7-4.0 x 1022 cm-3 - conditions very similar to the radiation/convection boundary zone within the Sun. The wavelength-dependent opacity in the 975-1775 eV photon energy range is 30-400% higher than models predict. This raises questions about how well we understand the behavior of atoms in HED plasma. These measurements may also help resolve decade-old discrepancies between solar model predictions and helioseismic observations. This talk will provide an overview of the measurements, investigations of possible errors, and ongoing experiments aimed at testing hypotheses to resolve the model-data discrepancy. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy under contract DE-AC04-94AL85000.

Identification of preoperative prediction factors of tumor subtypes for patients with solitary ground-glass opacity pulmonary nodules.

PubMed

Li, Meishuang; Wang, Yanan; Chen, Yulong; Zhang, Zhenfa

2018-01-17

Recent wide spread use of low-dose helical computed tomography for the screening of lung cancer have led to an increase in the detection rate of very faint and smaller lesions known as ground-glass opacity nodules. The purpose of this study was to investigate the clinical factors of lung cancer patients with solitary ground-glass opacity pulmonary nodules on computed tomography. A total of 423 resected solitary ground-glass opacity nodules were retrospectively evaluated. We analyzed the clinical, imaging and pathological data and investigated the clinical differences in patient with adenocarcinoma in situ / minimally invasive adenocarcinoma and those with invasive adenocarcinoma. Three hundred and ninety-three adenocarcinomas (92.9%) and 30 benign nodules were diagnosed. Age, the history of family cancer, serum carcinoembryonic antigen level, tumor size, ground-glass opacity types, and bubble-like sign in chest CT differed significantly between adenocarcinoma in situ / minimally invasive adenocarcinoma and invasive adenocarcinoma (p:0.008, 0.046, 0.000, 0.000, 0.000 and 0.001). Receiver operating characteristic curves and univariate analysis revealed that patients with more than 58.5 years, a serum carcinoembryonic antigen level > 1.970 μg/L, a tumor size> 13.50 mm, mixed ground-glass opacity nodules and a bubble-like sign were more likely to be diagnosed as invasive adenocarcinoma. The combination of five factors above had an area under the curve of 0.91, with a sensitivity of 82% and a specificity of 87%. The five-factor combination helps us to distinguish adenocarcinoma in situ / minimally invasive adenocarcinoma from invasive adenocarcinoma and to perform appropriate surgery for solitory ground-glass opacity nodules.

Robust lung identification in MSCT via controlled flooding and shape constraints: dealing with anatomical and pathological specificity

NASA Astrophysics Data System (ADS)

Fetita, Catalin; Tarando, Sebastian; Brillet, Pierre-Yves; Grenier, Philippe A.

2016-03-01

Correct segmentation and labeling of lungs in thorax MSCT is a requirement in pulmonary/respiratory disease analysis as a basis for further processing or direct quantitative measures: lung texture classification, respiratory functional simulations, intrapulmonary vascular remodeling evaluation, detection of pleural effusion or subpleural opacities, are only few clinical applications related to this requirement. Whereas lung segmentation appears trivial for normal anatomo-pathological conditions, the presence of disease may complicate this task for fully-automated algorithms. The challenges come either from regional changes of lung texture opacity or from complex anatomic configurations (e.g., thin septum between lungs making difficult proper lung separation). They make difficult or even impossible the use of classic algorithms based on adaptive thresholding, 3-D connected component analysis and shape regularization. The objective of this work is to provide a robust segmentation approach of the pulmonary field, with individualized labeling of the lungs, able to overcome the mentioned limitations. The proposed approach relies on 3-D mathematical morphology and exploits the concept of controlled relief flooding (to identify contrasted lung areas) together with patient-specific shape properties for peripheral dense tissue detection. Tested on a database of 40 MSCT of pathological lungs, the proposed approach showed correct identification of lung areas with high sensitivity and specificity in locating peripheral dense opacities.

Tamper asymmetry and its effect on transmission for x-ray driven opacity simulations

DOE PAGES

Morris, H. E.; Tregillis, I. L.; Hoffman, N. M.; ...

2017-08-01

This paper reports on synthetic transmission results from Lasnex [1] radiation-hydrodynamics simulations of opacity experiments carried out at Sandia National Laboratories' recently upgraded ZR facility. The focus is on experiments utilizing disk targets composed of a half-moon Fe/Mg mixture tamped on either end with 10- m CH and an additional 35- m beryllium tamper accessory on the end facing the spectrometer. Five x-ray sources with peak power ranging from 10 to 24 TW were used in the simulations to heat and backlight the opacity target. The dominant effect is that the beryllium behind the Fe/Mg mixture is denser and moremore » opaque than the beryllium unshielded by metal during the times of greatest importance for the transmission measurement for all drives. This causes the simulated transmission to be lower than expected, and this is most pronounced for the case using the lowest drive power. While beryllium has a low opacity, its areal density is sufficiently high such that the expected reduction of the measured transmission is significant. This situation leads to an overestimate of iron opacity by 10-215% for a photon energy range of 975- 1775 eV for the 10-TW case. It is shown that if the tamper conditions are known, the transmission through each component of the target can be calculated and the resulting opacity can be corrected.« less

Relationships (I) of International Classification of High-resolution Computed Tomography for Occupational and Environmental Respiratory Diseases with the ILO International Classification of Radiographs of Pneumoconioses for parenchymal abnormalities.

PubMed

Tamura, Taro; Suganuma, Narufumi; Hering, Kurt G; Vehmas, Tapio; Itoh, Harumi; Akira, Masanori; Takashima, Yoshihiro; Hirano, Harukazu; Kusaka, Yukinori

2015-01-01

The International Classification of High-resolution Computed Tomography (HRCT) for Occupational and Environmental Respiratory Diseases (ICOERD) has been developed for the screening, diagnosis, and epidemiological reporting of respiratory diseases caused by occupational hazards. This study aimed to establish a correlation between readings of HRCT (according to the ICOERD) and those of chest radiography (CXR) pneumoconiotic parenchymal opacities (according to the International Labor Organization Classification/International Classification of Radiographs of Pneumoconioses [ILO/ICRP]). Forty-six patients with and 28 controls without mineral dust exposure underwent posterior-anterior CXR and HRCT. We recorded all subjects' exposure and smoking history. Experts independently read CXRs (using ILO/ICRP). Experts independently assessed HRCT using the ICOERD parenchymal abnormalities grades for well-defined rounded opacities (RO), linear and/or irregular opacities (IR), and emphysema (EM). The correlation between the ICOERD summed grades and ILO/ICRP profusions was evaluated using Spearman's rank-order correlation. Twenty-three patients had small opacities on CXR. HRCT showed that 21 patients had RO; 20 patients, IR opacities; and 23 patients, EM. The correlation between ILO/ICRP profusions and the ICOERD grades was 0.844 for rounded opacities (p<0.01). ICOERD readings from HRCT scans correlated well with previously validated ILO/ICRP criteria. The ICOERD adequately detects pneumoconiotic micronodules and can be used for the interpretation of pneumoconiosis.

Is the Universe transparent?

NASA Astrophysics Data System (ADS)

Liao, Kai; Avgoustidis, A.; Li, Zhengxiang

2015-12-01

We present our study on cosmic opacity, which relates to changes in photon number as photons travel from the source to the observer. Cosmic opacity may be caused by absorption or scattering due to matter in the Universe, or by extragalactic magnetic fields that can turn photons into unobserved particles (e.g., light axions, chameleons, gravitons, Kaluza-Klein modes), and it is crucial to correctly interpret astronomical photometric measurements like type Ia supernovae observations. On the other hand, the expansion rate at different epochs, i.e., the observational Hubble parameter data H (z ), are obtained from differential ageing of passively evolving galaxies or from baryon acoustic oscillations and thus are not affected by cosmic opacity. In this work, we first construct opacity-free luminosity distances from H (z ) determinations, taking into consideration correlations between different redshifts for our error analysis. Moreover, we let the light-curve fitting parameters, accounting for distance estimation in type Ia supernovae observations, free to ensure that our analysis is authentically cosmological-model independent and gives a robust result. Any nonzero residuals between these two kinds of luminosity distances can be deemed as an indication of the existence of cosmic opacity. While a transparent Universe is currently consistent with the data, our results show that strong constraints on opacity (and consequently on physical mechanisms that could cause it) can be obtained in a cosmological-model-independent fashion.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Perry, Theodore Sonne; Dodd, Evan S.; DeVolder, Barbara Gloria

X-ray opacity is a crucial factor in all radiation-hydrodynamics calculations, yet it is one of the least validated of the material properties in simulation codes for high-energy-density plasmas. Recent opacity experiments at the Sandia Z-machine have shown up to factors of two discrepancies between theory and experiment for various mid-Z elements (Fe, Cr, Ni). These discrepancies raise doubts regarding the accuracy of the opacity models which are used in ICF and stewardship as well as in astrophysics. Therefore, a new experimental opacity platform has been developed on the National Ignition Facility (NIF), not only to verify the Z-machine experimental results,more » but also to extend the experiments to other temperatures and densities. Within the context of the national opacity strategy, the first NIF experiments were directed towards measuring the opacity of iron at a temperature of ~160 eV and an electron density of ~7xl021 cm-3(Anchor 1). The Z data agree with theory at these conditions, providing a reference point for validation of the NIF platform. Development shots on NIF have demonstrated the ability to create a sufficiently bright point backlighter using an imploding plastic capsule, and also a combined hohlraum, sample and laser drive able to produce iron plasmas at the desired conditions. Spectrometer qualification has been completed, albeit with additional improvements planned, and the first iron absorption spectra have now been obtained.« less

Opacity annotation of diffuse lung diseases using deep convolutional neural network with multi-channel information

NASA Astrophysics Data System (ADS)

Mabu, Shingo; Kido, Shoji; Hashimoto, Noriaki; Hirano, Yasushi; Kuremoto, Takashi

2018-02-01

This research proposes a multi-channel deep convolutional neural network (DCNN) for computer-aided diagnosis (CAD) that classifies normal and abnormal opacities of diffuse lung diseases in Computed Tomography (CT) images. Because CT images are gray scale, DCNN usually uses one channel for inputting image data. On the other hand, this research uses multi-channel DCNN where each channel corresponds to the original raw image or the images transformed by some preprocessing techniques. In fact, the information obtained only from raw images is limited and some conventional research suggested that preprocessing of images contributes to improving the classification accuracy. Thus, the combination of the original and preprocessed images is expected to show higher accuracy. The proposed method realizes region of interest (ROI)-based opacity annotation. We used lung CT images taken in Yamaguchi University Hospital, Japan, and they are divided into 32 × 32 ROI images. The ROIs contain six kinds of opacities: consolidation, ground-glass opacity (GGO), emphysema, honeycombing, nodular, and normal. The aim of the proposed method is to classify each ROI into one of the six opacities (classes). The DCNN structure is based on VGG network that secured the first and second places in ImageNet ILSVRC-2014. From the experimental results, the classification accuracy of the proposed method was better than the conventional method with single channel, and there was a significant difference between them.

40 CFR 63.1653 - Opacity standards.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 60 percent opacity, measured as a 6-minute average. (b) Blowing taps, poling and oxygen lancing of the tap hole; burndowns associated with electrode measurements; and maintenance activities associated...

Interpretation of the BRITE oscillation data of the hybrid pulsator ν Eridani: a call for the modification of stellar opacities

DOE Office of Scientific and Technical Information (OSTI.GOV)

Daszyńska-Daszkiewicz, J.; Pamyatnykh, A. A.; Walczak, P.

The analysis of the BRIght Target Explorer (BRITE) oscillation spectrum of the main-sequence early B-type star ν Eridani is presented in this paper. Only models with the modified mean opacity profile can account for the observed frequency ranges as well as for the values of some individual frequencies. The number of the κ-modified seismic models is constrained by the non-adiabatic parameter f, which is very sensitive to the opacity changes in the subphotospheric layers, where the pulsations are driven. We present an example of the model that satisfies all the above conditions. It seems that the OPLIB opacities are preferredmore » over those from the OPAL and OP projects. Finally and moreover, we discuss additional consequences of the opacity modification, namely, an enhancement of the efficiency of convection in the Z bump as well as an occurrence of close radial modes which is a kind of avoided-crossing phenomenon common for non-radial modes in standard main-sequence models.« less

Interpretation of the BRITE oscillation data of the hybrid pulsator ν Eridani: a call for the modification of stellar opacities

DOE PAGES

Daszyńska-Daszkiewicz, J.; Pamyatnykh, A. A.; Walczak, P.; ...

2016-12-22

The analysis of the BRIght Target Explorer (BRITE) oscillation spectrum of the main-sequence early B-type star ν Eridani is presented in this paper. Only models with the modified mean opacity profile can account for the observed frequency ranges as well as for the values of some individual frequencies. The number of the κ-modified seismic models is constrained by the non-adiabatic parameter f, which is very sensitive to the opacity changes in the subphotospheric layers, where the pulsations are driven. We present an example of the model that satisfies all the above conditions. It seems that the OPLIB opacities are preferredmore » over those from the OPAL and OP projects. Finally and moreover, we discuss additional consequences of the opacity modification, namely, an enhancement of the efficiency of convection in the Z bump as well as an occurrence of close radial modes which is a kind of avoided-crossing phenomenon common for non-radial modes in standard main-sequence models.« less

Influence of the atmospheric opacity cycle on the near surface environment of Gale Crater on Mars

NASA Astrophysics Data System (ADS)

de la Torre Juarez, Manuel; Gomez-Elvira, Javier; Guzewich, Scott David; Lemmon, Mark T.; Martinez, German; Mason, Emily; Navarro, Sara; Newman, Claire E.; Smith, Michael D.; Retortillo, Alvaro de Vicente

2016-10-01

The Mars atmospheric dust changes the capacity of the atmosphere to absorb solar radiation or release outgoing thermal infrared radiation. This alters the atmospheric heat exchange fluxes and can interfere with the global circulation. The response of near surface pressure, temperature and winds has been characterized at the higher northern latitudes of 45 degree N at the Viking landing sites. The Rover Environmental Monitoring Station (REMS) on Curiosity allows a similar characterization at near-equatorial latitudes of 4.5 degree S. Using MCAM-880 nm opacities as a measure of local atmospheric dust load, we analyze the response of changes in surface variables measured by REMS and compare to those observed by Viking. As on Viking, diurnal and semidiurnal pressure tide amplitudes track very closely the atmospheric opacity and the mean daily pressure shows the increased wave activity. Temperature tides show a more complex response that combines its sensitivity to changes in dust and cloud opacities. Differences in UV opacities for the REMS set of finite spectral windows are explored during the dust and clear seasons.

The relationship between elastomer opacity, colorimeter beam size, and measured colorimetric response.

PubMed

Rugh, E H; Johnston, W M; Hesse, N S

1991-01-01

The effect of opacity on the colorimetric responses of large-area and small-area colorimeters was determined using an elastomer intended for maxillofacial prosthetics use and containing various pigments at different concentrations. Opacity was determined by calculating the contrast ratio of 2-mm-thick specimens against black and white backings, using Kubelka-Munk analyses to correct for thickness and backing color variations. The measure of comparison of the two colorimeters was the relative difference in tristimulus reflectance, with the tristimulus reflectance of the large-area colorimeter as the basis of the relative difference. A significant quadratic relationship was found between contrast ratio and the relative difference in tristimulus reflectance. This relationship may be used to describe opacity without the need to make optical observations or measurements of a thin layer of material on contrasting backings. The small-area colorimeter produced color parameters that are a measure of the combined effects of both color and opacity. The importance of beam size considerations of optical measuring devices for translucent natural and prosthetic materials was emphasized.

Numerical investigations of potential systematic uncertainties in iron opacity measurements at solar interior temperatures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nagayama, T.; Bailey, J. E.; Loisel, G. P.

Iron opacity calculations presently disagree with measurements at an electron temperature of ~180–195 eV and an electron density of (2–4)×10 22cm –3, conditions similar to those at the base of the solar convection zone. The measurements use x rays to volumetrically heat a thin iron sample that is tamped with low-Z materials. The opacity is inferred from spectrally resolved x-ray transmission measurements. Plasma self-emission, tamper attenuation, and temporal and spatial gradients can all potentially cause systematic errors in the measured opacity spectra. In this article we quantitatively evaluate these potential errors with numerical investigations. The analysis exploits computer simulations thatmore » were previously found to reproduce the experimentally measured plasma conditions. The simulations, combined with a spectral synthesis model, enable evaluations of individual and combined potential errors in order to estimate their potential effects on the opacity measurement. Lastly, the results show that the errors considered here do not account for the previously observed model-data discrepancies.« less

High surface area bio-waste based carbon as a superior electrode for vanadium redox flow battery

NASA Astrophysics Data System (ADS)

Maharjan, Makhan; Bhattarai, Arjun; Ulaganathan, Mani; Wai, Nyunt; Oo, Moe Ohnmar; Wang, Jing-Yuan; Lim, Tuti Mariana

2017-09-01

Activated carbon (AC) with high surface area (1901 m2 g-1) is synthesized from low cost bio-waste orange (Citrus sinensis) peel for vanadium redox flow battery (VRB). The composition, structure and electrochemical properties of orange peel derived AC (OP-AC) are characterized by elemental analyzer, field emission-scanning electron microscopy, X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, cyclic voltammetry (CV), and electrochemical impedance spectroscopy. CV results show that OP-AC coated bipolar plate demonstrates improved electro-catalytic activity in both positive and negative side redox couples than the pristine bipolar plate electrode and this is ascribed to the high surface area of OP-AC which provides effective electrode area and better contact between the porous electrode and bipolar plate. Consequently, the performance of VRB in a static cell shows higher energy efficiency for OP-AC electrode than the pristine electrode at all current densities tested. The results suggest the OP-AC to be a promising electrode for VRB applications and can be incorporated into making conducting plastics electrode to lower the VRB cell stack weight and cost.

Numerical investigations of potential systematic uncertainties in iron opacity measurements at solar interior temperatures

DOE PAGES

Nagayama, T.; Bailey, J. E.; Loisel, G. P.; ...

2017-06-26

Iron opacity calculations presently disagree with measurements at an electron temperature of ~180–195 eV and an electron density of (2–4)×10 22cm –3, conditions similar to those at the base of the solar convection zone. The measurements use x rays to volumetrically heat a thin iron sample that is tamped with low-Z materials. The opacity is inferred from spectrally resolved x-ray transmission measurements. Plasma self-emission, tamper attenuation, and temporal and spatial gradients can all potentially cause systematic errors in the measured opacity spectra. In this article we quantitatively evaluate these potential errors with numerical investigations. The analysis exploits computer simulations thatmore » were previously found to reproduce the experimentally measured plasma conditions. The simulations, combined with a spectral synthesis model, enable evaluations of individual and combined potential errors in order to estimate their potential effects on the opacity measurement. Lastly, the results show that the errors considered here do not account for the previously observed model-data discrepancies.« less

Translucent Procedures, Abstraction without Opacity

DTIC Science & Technology

1993-10-01

Justi1ficatilon By- Distribut •c._/ rAviiii andi or Dist Sp• ialI I ..da A Guillermo Rozas Mazo (1931-1990). c~uyo desco de dar a sus hijos la cducaci6n... que dI no pudo recibir. con este trabajo realizo. Lo proinetido es deuda. Acknowledgments There are many people to whom I owe my sanity and to whom I...constant value). This expression gives us the value of the last unknown. 4. Once the residual system is solved, compute the value of the eliminated un

Studies of atmospheric dust from Viking IR thermal mapper data

NASA Technical Reports Server (NTRS)

Martin, T. Z.

1993-01-01

Following earlier work to map the dust opacity of the Mars atmosphere, a number of separate studies have been performed employing the radiometric measurements of the Viking IR Thermal Mappers. These efforts have resulted in a new perspective on the atmospheric dust distribution during the Viking Mission, as well as quantitative measures useful in the modeling of likely behavior at other times, and improved boundary conditions for circulation models of Mars. The significant findings from these studies are presented.

The Sun as a sub-GeV dark matter accelerator

NASA Astrophysics Data System (ADS)

Emken, Timon; Kouvaris, Chris; Nielsen, Niklas Grønlund

2018-03-01

Sub-GeV halo dark matter that enters the Sun can potentially scatter off hot solar nuclei and be ejected much faster than its incoming velocity. We derive an expression for the rate and velocity distribution of these reflected particles, taking into account the Sun's temperature and opacity. We further demonstrate that future direct-detection experiments could use these energetic reflected particles to probe light dark matter in parameter space that cannot be accessed via ordinary halo dark matter.

Titan's stratospheric temperatures - A case for dynamical inertia?

NASA Technical Reports Server (NTRS)

Flasar, F. M.; Conrath, B. J.

1990-01-01

Voyager IRIS spectral radiances in the nu4-band of CH4 for the Titan atmosphere exhibit a hemispheric asymmetry. While asymmetry in the meridional distribution of opacity about the equator cannot be discounted, attention is given to the need for angular momentum transport concurrent with seasonally varying temperatures in the Titan stratosphere, which would maintain the cyclostrophic thermal wind relation between zonal winds and temperatures. The adiabatic heating and cooling associated with these motions can produce the observed temperature asymmetry.

The (lack of) relation between straylight and visual acuity. Two domains of the point-spread-function.

PubMed

van den Berg, Thomas J T P

2017-05-01

The effect of cataract and other media opacities on functional vision is typically assessed clinically using visual acuity. In both clinical and basic research, straylight (the functional result of light scattering in the eye) is commonly measured. The purpose of the present study was to determine the link between these two measures: is visual acuity in cataract and other media opacities related to straylight? Interdependence between acuity and straylight is addressed from three different points of view: (1) Methodological: can acuity differences affect the measurement value of straylight, and vice versa? (2) Basic optics: does the optical process of light scattering in the human eye affect both straylight and visual acuity? (3) Statistical: how strongly are acuity and straylight correlated in the practice of important clinical conditions? Experimental and theoretical aspects will be considered, with a focus on normal ageing and cataract formation. (1) Methodological: testing potential effects of acuity, artificially manipulated with positive trial lenses, showed no effect on measured straylight values. Since light scattering in the eye involves a low percentage of the light and has large angular spreading, contrast reduction due to straylight is limited, resulting in virtually absent acuity effects. (2) Basic optics: light scattering from the human donor eye lens is found to have virtually no effect in the centre of the point-spread-function, also for cataractous lenses, resulting in virtually absent acuity effects. (3) Statistical: literature data on straylight and visual acuity show a weak correlation for the important groups of normal ageing and cataract populations. The point-spread-function of the normal ageing and cataractous human eye is built upon two rather independent basic parts. Aberrations control the central peak. Light scattering controls the periphery from about 1° onwards. The way acuity and straylight are measured ensures no confounding between them. Statistically within the normal ageing and cataract populations, visual acuity and straylight vary quite independently from each other. Visual acuity losses with cataract and other media opacities are not due to straylight, but caused by aberrations and micro-aberrations. Straylight defines disability glare, and causes symptoms of glare, haloes, hazy vision etc. Overall, visual acuity and straylight are rather independent aspects of quality of vision. © 2017 The Author Ophthalmic & Physiological Optics © 2017 The College of Optometrists.

Predicting Rosseland mean opacities of Aluminum using a difference converging method

NASA Astrophysics Data System (ADS)

Sun, Weiguo; Fan, Zhixiang; Zhang, Yi; Fu, Jia; Hu, Shide; Zhang, Lulu; Fan, Qunchao

2018-01-01

A difference converging method for opacity (DCMo) calculation is suggested to predict opacities and transmissions of metal plasmas at other photon energies that were not measured. The applications of the DCMo to the opacity and transmission calculations of Aluminum plasmas, in the spectral range of 73.5eV ≤ hν ≤ 245eV with Te = 20eV, and of 1475eV ≤ hν ≤ 1540eV with Te = 19eV, show that: 1) the DCMo correctly reproduce all important absorption structures of the Al plasmas and their corresponding intensities; 2) the agreement between the experimental and the DCMo transmissions is notably better than that between the experimental and some other computational transmissions like the ones obtained using OPAL and ATOMIC models.

Changes of Dust Opacity with Density in the Orion A Molecular Cloud

NASA Astrophysics Data System (ADS)

Roy, Arabindo; Martin, Peter G.; Polychroni, Danae; Bontemps, Sylvain; Abergel, Alain; André, Philippe; Arzoumanian, Doris; Di Francesco, James; Hill, Tracey; Konyves, Vera; Nguyen-Luong, Quang; Pezzuto, Stefano; Schneider, Nicola; Testi, Leonardo; White, Glenn

2013-01-01

We have studied the opacity of dust grains at submillimeter wavelengths by estimating the optical depth from imaging at 160, 250, 350, and 500 μm from the Herschel Gould Belt Survey and comparing this to a column density obtained from the Two Micron All Sky Survey derived color excess E(J - K s). Our main goal was to investigate the spatial variations of the opacity due to "big" grains over a variety of environmental conditions and thereby quantify how emission properties of the dust change with column (and volume) density. The central and southern areas of the Orion A molecular cloud examined here, with N H ranging from 1.5 × 1021 cm-2 to 50 × 1021 cm-2, are well suited to this approach. We fit the multi-frequency Herschel spectral energy distributions (SEDs) of each pixel with a modified blackbody to obtain the temperature, T, and optical depth, τ1200, at a fiducial frequency of 1200 GHz (250 μm). Using a calibration of N H/E(J - Ks ) for the interstellar medium (ISM) we obtained the opacity (dust emission cross-section per H nucleon), σe(1200), for every pixel. From a value ~1 × 10-25 cm2 H-1 at the lowest column densities that is typical of the high-latitude diffuse ISM, σe(1200) increases as N 0.28 H over the range studied. This is suggestive of grain evolution. Integrating the SEDs over frequency, we also calculated the specific power P (emission power per H) for the big grains. In low column density regions where dust clouds are optically thin to the interstellar radiation field (ISRF), P is typically 3.7 × 10-31 W H-1, again close to that in the high-latitude diffuse ISM. However, we find evidence for a decrease of P in high column density regions, which would be a natural outcome of attenuation of the ISRF that heats the grains, and for localized increases for dust illuminated by nearby stars or embedded protostars.

First Light LBT AO Images of HR 8799 bcde at 1.6 and 3.3 μm: New Discrepancies between Young Planets and Old Brown Dwarfs

NASA Astrophysics Data System (ADS)

Skemer, Andrew J.; Hinz, Philip M.; Esposito, Simone; Burrows, Adam; Leisenring, Jarron; Skrutskie, Michael; Desidera, Silvano; Mesa, Dino; Arcidiacono, Carmelo; Mannucci, Filippo; Rodigas, Timothy J.; Close, Laird; McCarthy, Don; Kulesa, Craig; Agapito, Guido; Apai, Daniel; Argomedo, Javier; Bailey, Vanessa; Boutsia, Konstantina; Briguglio, Runa; Brusa, Guido; Busoni, Lorenzo; Claudi, Riccardo; Eisner, Joshua; Fini, Luca; Follette, Katherine B.; Garnavich, Peter; Gratton, Raffaele; Guerra, Juan Carlos; Hill, John M.; Hoffmann, William F.; Jones, Terry; Krejny, Megan; Males, Jared; Masciadri, Elena; Meyer, Michael R.; Miller, Douglas L.; Morzinski, Katie; Nelson, Matthew; Pinna, Enrico; Puglisi, Alfio; Quanz, Sascha P.; Quiros-Pacheco, Fernando; Riccardi, Armando; Stefanini, Paolo; Vaitheeswaran, Vidhya; Wilson, John C.; Xompero, Marco

2012-07-01

As the only directly imaged multiple planet system, HR 8799 provides a unique opportunity to study the physical properties of several planets in parallel. In this paper, we image all four of the HR 8799 planets at H band and 3.3 μm with the new Large Binocular Telescope adaptive optics system, PISCES, and LBTI/LMIRCam. Our images offer an unprecedented view of the system, allowing us to obtain H and 3.3 μm photometry of the innermost planet (for the first time) and put strong upper limits on the presence of a hypothetical fifth companion. We find that all four planets are unexpectedly bright at 3.3 μm compared to the equilibrium chemistry models used for field brown dwarfs, which predict that planets should be faint at 3.3 μm due to CH4 opacity. We attempt to model the planets with thick-cloudy, non-equilibrium chemistry atmospheres but find that removing CH4 to fit the 3.3 μm photometry increases the predicted L' (3.8 μm) flux enough that it is inconsistent with observations. In an effort to fit the spectral energy distribution of the HR 8799 planets, we construct mixtures of cloudy atmospheres, which are intended to represent planets covered by clouds of varying opacity. In this scenario, regions with low opacity look hot and bright, while regions with high opacity look faint, similar to the patchy cloud structures on Jupiter and L/T transition brown dwarfs. Our mixed-cloud models reproduce all of the available data, but self-consistent models are still necessary to demonstrate their viability. The LBT is an international collaboration among institutions in the United States, Italy, and Germany. LBT Corporation partners are as follows: The University of Arizona on behalf of the Arizona university system; Istituto Nazionale di AstroÞsica, Italy; LBT Beteiligungsgesellschaft, Germany, representing the Max-Planck Society, the Astrophysical Institute Potsdam, and Heidelberg University; The Ohio State University, and The Research Corporation, on behalf of The University of Notre Dame, University of Minnesota, and University of Virginia.

Opacity broadening and interpretation of suprathermal CO linewidths: Macroscopic turbulence and tangled molecular clouds

NASA Astrophysics Data System (ADS)

Hacar, A.; Alves, J.; Burkert, A.; Goldsmith, P.

2016-06-01

Context. Since their first detection in the interestellar medium, (sub-)millimeter line observations of different CO isotopic variants have routinely been employed to characterize the kinematic properties of the gas in molecular clouds. Many of these lines exhibit broad linewidths that greatly exceed the thermal broadening expected for the low temperatures found within these objects. These observed suprathermal CO linewidths are assumed to originate from unresolved supersonic motions inside clouds. Aims: The lowest rotational J transitions of some of the most abundant CO isotopologues, 12CO and 13CO, are found to present large optical depths. In addition to well-known line saturation effects, these large opacities present a non-negligible contribution to their observed linewidths. Typically overlooked in the literature, in this paper we aim to quantify the impact of these opacity broadening effects on the current interpretation of the CO suprathermal line profiles. Methods: Combining large-scale observations and LTE modeling of the ground J = 1-0 transitions of the main 12CO, 13CO, C18O isotopologues, we have investigated the correlation of the observed linewidths as a function of the line opacity in different regions of the Taurus molecular cloud. Results: Without any additional contributions to the gas velocity field, a large fraction of the apparently supersonic (ℳ ~ 2-3) linewidths measured in both 12CO and 13CO (J = 1-0) lines can be explained by the saturation of their corresponding sonic-like, optically thin C18O counterparts assuming standard isotopic fractionation. Combined with the presence of multiple components detected in some of our C18O spectra, these opacity effects also seem to be responsible for most of the highly supersonic linewidths (ℳ > 8-10) detected in some of the broadest 12CO and 13CO spectra in Taurus. Conclusions: Our results demonstrate that most of the suprathermal 12CO and 13CO linewidths reported in nearby clouds like Taurus could be primarily created by a combination of opacity broadening effects and multiple gas velocity components blended in these saturated emission lines. Once corrected by their corresponding optical depth, each of these gas components present transonic intrinsic linewidths consistently traced by the three isotopologues, 12CO, 13CO, and C18O, with differences within a factor of 2. Highly correlated and velocity-coherent at large scales, the largest and highly supersonic velocity differences inside clouds are generated by the relative motions between individual gas components. In contrast to the classical interpretation within the framework of microscopic turbulence, this highly discretized structure of the molecular gas traced in CO suggest that the gas dynamics inside molecular clouds could be better described by the properties of a fully resolved macroscopic turbulence.

Molecular clouds in galaxies with different Z - Fragmentation of diffuse clouds driven by opacity

NASA Technical Reports Server (NTRS)

Franco, Jose; Cox, Donald P.

1986-01-01

Molecular clouds are formed from diffuse interstellar clouds when the external ultraviolet radiation field is prevented from penetrating into the cloud. The opacity is provided mainly by dust grains and the required column density to the cloud center is larger than about 5 x 10 to the 20th (solar Z/Z)/sq cm. This high-opacity criterion could have a significant impact on the radial trends observed in spiral galaxies, and on the distinctions between spiral and dwarf irregular galaxies.

Computational Design of Short Pulse Laser Driven Iron Opacity Measurements at Stellar-Relevant Conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Martin, Madison E.

Opacity is a critical parameter in the simulation of radiation transport in systems such as inertial con nement fusion capsules and stars. The resolution of current disagreements between solar models and helioseismological observations would bene t from experimental validation of theoretical opacity models. Overall, short pulse laser heated iron experiments reaching stellar-relevant conditions have been designed with consideration of minimizing tamper emission and optical depth effects while meeting plasma condition and x-ray emission goals.

Free-free opacity in dense plasmas with an average atom model

DOE PAGES

Shaffer, Nathaniel R.; Ferris, Natalie G.; Colgan, James Patrick; ...

2017-02-28

A model for the free-free opacity of dense plasmas is presented. The model uses a previously developed average atom model, together with the Kubo-Greenwood model for optical conductivity. This, in turn, is used to calculate the opacity with the Kramers-Kronig dispersion relations. Furthermore, comparisons to other methods for dense deuterium results in excellent agreement with DFT-MD simulations, and reasonable agreement with a simple Yukawa screening model corrected to satisfy the conductivity sum rule.

Free-free opacity in dense plasmas with an average atom model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shaffer, Nathaniel R.; Ferris, Natalie G.; Colgan, James Patrick

A model for the free-free opacity of dense plasmas is presented. The model uses a previously developed average atom model, together with the Kubo-Greenwood model for optical conductivity. This, in turn, is used to calculate the opacity with the Kramers-Kronig dispersion relations. Furthermore, comparisons to other methods for dense deuterium results in excellent agreement with DFT-MD simulations, and reasonable agreement with a simple Yukawa screening model corrected to satisfy the conductivity sum rule.

New dust opacity maps from Viking IR thermal mapper data

NASA Technical Reports Server (NTRS)

Martin, T. Z.; Richardson, M. I.

1992-01-01

Mapping of dust opacity of the Martian atmosphere, using the silicate-induced absorption of 9 micron radiation, was performed with the Viking Infrared Thermal Mapper (IRTM) data for several local dust storms and in a global sense. We present here the first results from an effort to extend the earlier mapping work to the period of the 1977b major storm, and to concentrate attention on the details of opacity behavior during the initial phases of the 1977a and b storms.

Non-LTE H2+ as the source of missing opacity in the solar atmosphere

NASA Technical Reports Server (NTRS)

Swamy, K. S. K.; Stecher, T. P.

1974-01-01

The population of the various vibrational levels of the H2+ molecule has been calculated from the consideration of formation and destruction mechanisms. The resulting population is used in calculating the total absorption due to H2+ and is compared with the other known sources of opacity at several optical depths of the solar atmosphere. It is shown that the absorption due to H2+ can probably account for the missing ultraviolet opacity in the solar atmosphere.

40 CFR 63.1653 - Opacity standards.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Opacity standards. No owner or operator shall cause emissions exiting from a shop due solely to operations... during any performance test, with the following exceptions: (a) Visible particulate emissions from a shop...

Canines are affected in 16-year-olds with molar-incisor hypomineralisation (MIH): an epidemiological study based on the Tromsø study: "Fit Futures".

PubMed

Schmalfuss, A; Stenhagen, K R; Tveit, A B; Crossner, C-G; Espelid, I

2016-04-01

This was to determine the prevalence, distribution of affected teeth and severity of MIH in adolescents from Northern Norway. It was part of a cross-sectional health survey Fit Futures including 16-year-olds from two neighbouring municipalities, Tromsø and Balsfjord. The prevalence of MIH was 13.9% (110 of 794). The maxillary first permanent molars (FPMs) were 1.6 times more frequently affected than in the mandible (P < 0.001). The FPMs on the right side were 1.2 times more often affected than the FPMs on the left side (P = 0.038). The maxillary incisors were 2.5 times more often affected than the incisors in the mandible (P < 0.001). The proportions of participants whose canines and incisors were involved were 22.8 and 41.8%, respectively. Altogether 201 FPMs were affected; 54.0% of these had opacities only, 24.3% had posteruptive breakdown (PEB), 18.8% had atypical restorations, and 3.0% had been extracted due to MIH. The buccal surfaces were most often affected in FPMs. More severe lesions were found in the mandibular FPMs compared with the maxillary FPMs (P = 0.002). In the lower canines, only opacities were recorded, while in the upper jaw 13.0% of the affected canines showed PEBs. The distribution of MIH in the dentition was not symmetrical. The prevalence of MIH (13.9%) in the study population of 16-year-olds from Northern Norway is consistent with previous Scandinavian reports. The distribution pattern shows that one participant in four with MIH had at least one affected canine. Further studies are needed to describe the localisation of defects on the enamel surface and to relate these findings to enamel thickness and the duration of amelogenesis.

Capsule implosions for continuum x-ray backlighting of opacity samples at the National Ignition Facility

NASA Astrophysics Data System (ADS)

Opachich, Y. P.; Heeter, R. F.; Barrios, M. A.; Garcia, E. M.; Craxton, R. S.; King, J. A.; Liedahl, D. A.; McKenty, P. W.; Schneider, M. B.; May, M. J.; Zhang, R.; Ross, P. W.; Kline, J. L.; Moore, A. S.; Weaver, J. L.; Flippo, K. A.; Perry, T. S.

2017-06-01

Direct drive implosions of plastic capsules have been performed at the National Ignition Facility to provide a broad-spectrum (500-2000 eV) X-ray continuum source for X-ray transmission spectroscopy. The source was developed for the high-temperature plasma opacity experimental platform. Initial experiments using 2.0 mm diameter polyalpha-methyl styrene capsules with ˜20 μm thickness have been performed. X-ray yields of up to ˜1 kJ/sr have been measured using the Dante multichannel diode array. The backlighter source size was measured to be ˜100 μm FWHM, with ˜350 ps pulse duration during the peak emission stage. Results are used to simulate transmission spectra for a hypothetical iron opacity sample at 150 eV, enabling the derivation of photometrics requirements for future opacity experiments.

Physical and Chemical Processes Opacity Project: an Overview and Some Preliminary Results

NASA Astrophysics Data System (ADS)

Mendoza, C.

1990-11-01

RESUMEN. El Proyecto de la Opacidad es un esfuerzo internacional dedicado a calcular con precisi6n la gran cantidad de datos at6micos que se necesitan para estimar opacidades en los envolventes estelares. Describimos el panorama general del proyecto incluyendo aspectos astrofisicos, flsico-at6micos y computacionales. El volumen y calidad de los datos que se estan generando se puede apreciar en los resultados preliminares que se presentan. ABSTRACT The Opacity Project is an international effort dedicated to the calculation of the vast, accurate, atomic data required to estimate stellar envelope opacities. We give an overview of the project including astrophysical, atomic-physical and computational aspects. The volume and quality of the data which are being generated can be appreciated in the preliminary results that are presented. }% words: ATOMIC PROCESSES - OPACITIES - STARS-INThRIORS

Night and Day: The Opacity of Clouds Measured by the Mars Orbiter Laser Altimeter (MOLA)

NASA Technical Reports Server (NTRS)

Neumann, G. A.; Wilson, R. J.

2006-01-01

The Mars Orbiter Laser Altimeter (MOLA) [l] on the Mars Global Surveyor spacecraft ranged to clouds over the course of nearly two Mars years [2] using an active laser ranging system. While ranging to the surface, the instrument was also able to measure the product of the surface reflectivity with the two-way atmospheric transmission at 1064 nm. Furthermore, the reflectivity has now been mapped over seasonal cycles using the passive radiometric capability built into MOLA [3]. Combining these measurements, the column opacity may be inferred. MOLA uniquely provides these measurements both night and day. This study examines the pronounced nighttime opacity of the aphelion season tropical water ice clouds, and the indiscernibly low opacity of the southern polar winter clouds. The water ice clouds (Figure 1) do not themselves trigger the altimeter but have measured opacities tau > 1.5 and are temporally and spatially correlated with temperature anomalies predicted by a Mars Global Circulation Model (MGCM) that incorporates cloud radiative effects [4]. The south polar CO2 ice clouds trigger the altimeter with a very high backscatter cross-section over a thickness of 3-9 m and are vertically dispersed over several km, but their total column opacities lie well below the MOLA measurement limit of tau = 0.7. These clouds correspond to regions of supercooled atmosphere that may form either very large specularly reflecting particles [2] or very compact, dense concentrations (>5x10(exp 6)/cu m) of 100-p particles

Tamper asymmetry and its effect on transmission for x-ray driven opacity simulations

NASA Astrophysics Data System (ADS)

Morris, H. E.; Tregillis, I. L.; Hoffman, N. M.; Sherrill, M. E.; Fontes, C. J.; Marshall, A. J.; Urbatsch, T. J.; Bradley, P. A.

2017-09-01

This paper reports on synthetic transmission results from Lasnex [Zimmerman and Kruer, Comments Plasma Phys. 2, 51 (1975)] radiation-hydrodynamics simulations of opacity experiments carried out at Sandia National Laboratories' recently upgraded ZR facility. The focus is on experiments utilizing disk targets composed of a half-moon Fe/Mg mixture tamped on either end with 10-μm CH and an additional 35-μm beryllium tamper accessory on the end facing the spectrometer. Five x-ray sources with peak power ranging from 10 to 24 TW were used in the simulations to heat and backlight the opacity target. The dominant effect is that the beryllium behind the Fe/Mg mixture is denser and more opaque than the beryllium unshielded by metal during the times of greatest importance for the transmission measurement for all drives. This causes the simulated transmission to be lower than expected, and this is most pronounced for the case using the lowest drive power. While beryllium has a low opacity, its areal density is sufficiently high such that the expected reduction of the measured transmission is significant. This situation leads to an overestimate of iron opacity by 10%-215% for a photon energy range of 975-1775 eV for the 10-TW case. It is shown that if the tamper conditions are known, the transmission through each component of the target can be calculated and the resulting opacity can be corrected.

Corneal Opacity in Domestic Ducks Experimentally Infected With H5N1 Highly Pathogenic Avian Influenza Virus.

PubMed

Yamamoto, Y; Nakamura, K; Yamada, M; Mase, M

2016-01-01

Domestic ducks can be a key factor in the regional spread of H5N1 highly pathogenic avian influenza (HPAI) virus in Asia. The authors performed experimental infections to examine the relationship between corneal opacity and H5N1 HPAI virus infection in domestic ducks (Anas platyrhyncha var domestica). A total of 99 domestic ducks, including 3 control birds, were used in the study. In experiment 1, when domestic ducks were inoculated intranasally with 2 H5N1 HPAI viruses, corneal opacity appeared more frequently than neurologic signs and mortality. Corneal ulceration and exophthalmos were rare findings. Histopathologic examinations of the eyes of domestic ducks in experiment 2 revealed that corneal opacity was due to the loss of corneal endothelial cells and subsequent keratitis with edema. Influenza viral antigen was detected in corneal endothelial cells and some other ocular cells by immunohistochemistry. Results suggest that corneal opacity is a characteristic and frequent finding in domestic ducks infected with the H5N1 HPAI virus. Confirming this ocular change may improve the detection rate of infected domestic ducks in the field. © The Author(s) 2015.

Detailed opacity calculations for stellar models

NASA Astrophysics Data System (ADS)

Pain, Jean-Christophe; Gilleron, Franck

2016-10-01

We present a state of the art of precise spectral opacity calculations illustrated by stellar applications. The essential role of laboratory experiments to check the quality of the computed data is underlined. We review some X-ray and XUV laser and Z-pinch photo-absorption measurements as well as X-ray emission spectroscopy experiments of hot dense plasmas produced by ultra-high-intensity laser interaction. The measured spectra are systematically compared with the fine-structure opacity code SCO-RCG. Focus is put on iron, due to its crucial role in the understanding of asteroseismic observations of Beta Cephei-type and Slowly Pulsating B stars, as well as in the Sun. For instance, in Beta Cephei-type stars (which should not be confused with Cepheid variables), the iron-group opacity peak excites acoustic modes through the kappa-mechanism. A particular attention is paid to the higher-than-predicted iron opacity measured on Sandia's Z facility at solar interior conditions (boundary of the convective zone). We discuss some theoretical aspects such as orbital relaxation, electron collisional broadening, ionic Stark effect, oscillator-strength sum rules, photo-ionization, or the ``filling-the-gap'' effect of highly excited states.

Opacity Variations in the Ionized Absorption in NGC 3783: A Compact Absorber

NASA Astrophysics Data System (ADS)

Krongold, Y.; Nicastro, F.; Brickhouse, N. S.; Elvis, M.; Mathur, S.

2005-04-01

We show that the Fe VII-Fe XII M-shell unresolved transition array (UTA) in the Chandra HETGS observation of NGC 3783 (900 ks) clearly changes in opacity on a timescale of 31 days, responding to a factor of ~2 change in the ionizing continuum. The opacity variation is observed at a level >10 σ. There is also evidence for variability in the O VI K edge (at ~3 σ). The observed changes are consistent with the gas producing these absorption features (i.e., the low-ionization component) being close to photoionization equilibrium. The gas responsible for the Fe XVII-Fe XXII L-shell absorption (i.e., the high-ionization component) does not seem to be responding as expected in photoionization equilibrium. The observed change in opacity for the UTA implies a density >1×104 cm-3, thus locating the gas within 6 pc of the X-ray source. The scenario in which the gas is composed of a continuous radial range of ionization structures is ruled out, as in such scenario, no opacity variations are expected. Rather, the structure of the absorber is likely composed of heavily clumped gas.

40 CFR 63.1653 - Opacity standards.

Code of Federal Regulations, 2014 CFR

2014-07-01

... Silicomanganese § 63.1653 Opacity standards. No owner or operator shall cause emissions exiting from a shop due... particulate emissions from a shop due solely to operation of a semi-closed submerged arc furnace, may exceed...

40 CFR 63.1653 - Opacity standards.

Code of Federal Regulations, 2013 CFR

2013-07-01

... Silicomanganese § 63.1653 Opacity standards. No owner or operator shall cause emissions exiting from a shop due... particulate emissions from a shop due solely to operation of a semi-closed submerged arc furnace, may exceed...

40 CFR 63.1653 - Opacity standards.

Code of Federal Regulations, 2012 CFR

2012-07-01

... Silicomanganese § 63.1653 Opacity standards. No owner or operator shall cause emissions exiting from a shop due... particulate emissions from a shop due solely to operation of a semi-closed submerged arc furnace, may exceed...

[The "light" water effect on lenticular opacity development in mice after repeated low dose gamma-irradiation].

PubMed

Abrosimova, A N; Rakov, D V; Siniak, Iu E

2009-01-01

Action of "light" water with reduced quantities of heavy stable hydrogen and 18O ions on incidence and progress of lenticular opacity was studied in gamma-irradiated mice (60Co, 1.0 Gy). The animals were subjected to electroophthalmoscopy regularly till end of life time. The observation showed that chronic intake of "light" water safeguarded the irradiated mice against lenticular opacity. The experimental data indicate that "light" water strengthens the general body resistance as well as slows down aging of mammals.

Metal Hydride and Alkali Halide Opacities in Extrasolar Giant Planets and Cool Stellar Atmospheres

NASA Technical Reports Server (NTRS)

Weck, Philippe F.; Stancil, Phillip C.; Kirby, Kate; Schweitzer, Andreas; Hauschildt, Peter H.

2006-01-01

The lack of accurate and complete molecular line and continuum opacity data has been a serious limitation to developing atmospheric models of cool stars and Extrasolar Giant Planets (EGPs). We report our recent calculations of molecular opacities resulting from the presence of metal hydrides and alkali halides. The resulting data have been included in the PHOENIX stellar atmosphere code (Hauschildt & Baron 1999). The new models, calculated using spherical geometry for all gravities considered, also incorporate our latest database of nearly 670 million molecular lines, and updated equations of state.

Dental caries and developmental defects of enamel in relation to fluoride levels in drinking water in an arid area of Sri Lanka.

PubMed

Ekanayake, L; van der Hoek, W

2002-01-01

The study was conducted to assess caries and developmental defects of enamel in relation to fluoride levels in drinking water and the association between caries experience and the severity of diffuse opacities in children living in Uda Walawe, an area with varying concentrations of fluoride in drinking water in Sri Lanka. A total of 518 14-year-old children who were lifelong residents in this area were examined for dental caries and developmental defects of enamel. But the present analysis is confined to 486 children from whom drinking water samples were collected. The prevalence of enamel defects and diffuse opacities ranged from 27 to 57% while the prevalence of caries ranged from 18 to 29% in the different fluoride exposure groups. The prevalence of enamel defects increased significantly with the increase in the fluoride level in drinking water. Both the caries prevalence and the mean caries experience were significantly higher in children with diffuse opacities than in those without in the group consuming water containing >0.70 mg/l of fluoride. The association between dental caries and the severity of diffuse opacities was also significant only in this group. Children with the mildest form of opacities (DDE scores 3 and 4) had the lowest DMFS (0.25 +/- 0.7), and the highest DMFS (1.1 +/- 1.7) was found in those with the most severe form of opacities (DDE score 6). In conclusion, the relationship that was observed in this study between fluoride levels in drinking water, diffuse opacities and caries suggests that the appropriate level of fluoride in drinking water for arid areas of Sri Lanka is around 0.3 mg/l. Also individuals with severe forms of enamel defects in high-fluoride areas are susceptible to dental caries. Copyright 2002 S. Karger AG, Basel

Evaluation of low-contrast perceptibility in dental restorative materials under the influence of ambient light conditions

PubMed Central

Lobo, I C; Lemos, A L B; Aguiar, M F

2015-01-01

Objectives: This study aimed to assess how details on dental restorative composites with different radio-opacities are perceived under the influence of ambient light. Methods: Resin composite step wedges (six steps, each 1-mm thick) were custom manufactured from three materials, respectively: (M1) Filtek™ Z350 (3M/ESPE, Saint Paul, MN); (M2) Prisma AP.H™ (Dentsply International Inc., Brazil) and (M3) Glacier® (SDI Limited, Victoria, Australia). Each step of the manufactured wedge received three standardized drillings of different diameters and depths. An aluminium (Al) step wedge with 12 steps (1-mm thick) was used as an internal standard to calculate the radio-opacity as pixel intensity values. Standardized digital images of the set were obtained, and 11 observers independently recorded the images, noting the number of noticeable details (drillings) under 2 dissimilar conditions: in a light environment (light was turned on in the room) and in low-light conditions (light in the room was turned off). The differences between images in terms of the number of details that were observed were statistically compared using ANOVA, Cronbach's alpha coefficient and Wilcoxon and Kruskal–Wallis tests, with a significance level setting of 5% (α = 0.05). Results: The M2 showed higher radio-opacity, the M1 displayed intermediate radio-opacity and the M3 showed lower radio-opacity, respectively; however, all three were without significance (p > 0.05) compared with each other. The differences in radio-opacity resulted in a significant variation (p < 0.05) in the number of noticeable details in the image, which were influenced by characteristics of details, in addition to the ambient-light level. Conclusions: The radio-opacity of materials and ambient light can affect the perception of details in digital radiographic images. PMID:25629721

First-principles opacity table of warm dense deuterium for inertial-confinement-fusion applications.

PubMed

Hu, S X; Collins, L A; Goncharov, V N; Boehly, T R; Epstein, R; McCrory, R L; Skupsky, S

2014-09-01

Accurate knowledge of the optical properties of a warm dense deuterium-tritium (DT) mixture is important for reliable design of inertial confinement fusion (ICF) implosions using radiation-hydrodynamics simulations. The opacity of a warm dense DT shell essentially determines how much radiation from hot coronal plasmas can be deposited in the DT fuel of an imploding capsule. Even for the simplest species of hydrogen, the accurate calculation of their opacities remains a challenge in the warm-dense matter regime because strong-coupling and quantum effects play an important role in such plasmas. With quantum-molecular-dynamics (QMD) simulations, we have derived a first-principles opacity table (FPOT) of deuterium (and the DT mixture by mass scaling) for a wide range of densities from ρ(D)=0.5 to 673.518g/cm(3) and temperatures from T=5000K up to the Fermi temperature T(F) for each density. Compared with results from the astrophysics opacity table (AOT) currently used in our hydrocodes, the FPOT of deuterium from our QMD calculations has shown a significant increase in opacity for strongly coupled and degenerate plasma conditions by a factor of 3-100 in the ICF-relevant photon-energy range. As conditions approach those of classical plasma, the opacity from the FPOT converges to the corresponding values of the AOT. By implementing the FPOT of deuterium and the DT mixture into our hydrocodes, we have performed radiation-hydrodynamics simulations for low-adiabat cryogenic DT implosions on the OMEGA laser and for direct-drive-ignition designs for the National Ignition Facility. The simulation results using the FPOT show that the target performance (in terms of neutron yield and energy gain) could vary from ∼10% up to a factor of ∼2 depending on the adiabat of the imploding DT capsule; the lower the adiabat, the more variation is seen in the prediction of target performance when compared to the AOT modeling.

Detection of artificial air space opacities with digital radiography: ex vivo study on enhanced latitude post-processing.

PubMed

Biederer, J; Bolte, H; Schmidt, T; Charalambous, N; Both, M; Kopp, U; Hoffmann, B; Freitag-Wolf, S; Van Metter, R; Heller, M

2010-03-01

To evaluate in a.-p. digital chest radiograms of an ex vivo system if increased latitude and enhanced image detail contrast (EVP) improve the accuracy of detecting artificial air space opacities in parts of the lung that are superimposed by the diaphragm. 19 porcine lungs were inflated inside a chest phantom, prepared with 20-50 ml gelatin-stabilized liquid to generate alveolar air space opacities, and examined with direct radiography (3.0 × 2.5 k detector/ 125 kVp/ 4 mAs). 276 a.-p. images with and without EVP of 1.0-3.0 were presented to 6 observers. 8 regions were read for opacities, the reference was defined by CT. Statistics included sensitivity/specificity, interobserver variability, and calculation of Az (area under ROC curve). Behind the diaphragm (opacities in 32/92 regions), the median sensitivity increased from 0.35 without EVP to 0.53-0.56 at EVP 1.5-3.0 (significant in 5/6 observers). The specificity decreased from 0.96 to 0.90 (significant in 6/6), and the Az value and interobserver correlation increased from 0.66 to 0.74 and 0.39 to 0.48, respectively. Above the diaphragm, the median sensitivity for artificial opacities (136/276 regions) increased from 0.71 to 0.77-0.82 with EVP (significant in 4/6 observers). The specificity and Az value decreased from 0.76 to 0.62 and 0.74 to 0.70, respectively, (significant in 3/6). In this ex vivo experiment, EVP improved the diagnostic accuracy for artificial air space opacities in the superimposed parts of the lung (area under the ROC curve). Above the diaphragm, the accuracy was not affected due to a tradeoff in sensitivity/specificity. © Georg Thieme Verlag KG Stuttgart · New York.

The Moon Illusion and the Height of the Sky

NASA Astrophysics Data System (ADS)

Abhyankar, K. D.

1989-09-01

It is shown that the apparently flattened celestial vault can be represented by a geocentric sphere at a height of 3000-4000 km above the surface of the earth. It is also argued that our eye estimates the distance to this `sky sphere' by its apparent opacity which is a function of the air mass. A hypothesis regarding the physiology of distance vision is proposed.

An Empirical Determination of the Intergalactic Background Light Using Near-Infrared Deep Galaxy Survey Data Out to 5 Micrometers and the Gamma-Ray Opacity of the Universe

NASA Technical Reports Server (NTRS)

Scully, Sean T.; Malkan, Matthew A.; Stecker, Floyd W.

2014-01-01

We extend our previous model-independent determination of the intergalactic background light, based purely on galaxy survey data, out to a wavelength of 5 micrometers. Our approach enables us to constrain the range of photon densities, based on the uncertainties from observationally determined luminosity densities and colors. We further determine a 68% confidence upper and lower limit on the opacity of the universe to gamma-rays up to energies of 1.6/(1 + z) terraelectron volts. A comparison of our lower limit redshift-dependent opacity curves to the opacity limits derived from the results of both ground-based air Cerenkov telescope and Fermi-LAT observations of PKS 1424+240 allows us to place a new upper limit on the redshift of this source, independent of IBL modeling.

An empirical determination of the intergalactic background light using near-infrared deep galaxy survey data out to 5 μm and the gamma-ray opacity of the universe

DOE Office of Scientific and Technical Information (OSTI.GOV)

Scully, Sean T.; Malkan, Matthew A.; Stecker, Floyd W., E-mail: Floyd.W.Stecker@nasa.gov

2014-04-01

We extend our previous model-independent determination of the intergalactic background light, based purely on galaxy survey data, out to a wavelength of 5 μm. Our approach enables us to constrain the range of photon densities, based on the uncertainties from observationally determined luminosity densities and colors. We further determine a 68% confidence upper and lower limit on the opacity of the universe to γ-rays up to energies of 1.6/(1 + z) TeV. A comparison of our lower limit redshift-dependent opacity curves to the opacity limits derived from the results of both ground-based air Cerenkov telescope and Fermi-LAT observations of PKSmore » 1424+240 allows us to place a new upper limit on the redshift of this source, independent of IBL modeling.« less

Models of H II regions - Heavy element opacity, variation of temperature

NASA Technical Reports Server (NTRS)

Rubin, R. H.

1985-01-01

A detailed set of H II region models that use the same physics and self-consistent input have been computed and are used to examine where in parameter space the effects of heavy element opacity is important. The models are briefly described, and tabular data for the input parameters and resulting properties of the models are presented. It is found that the opacities of C, Ne, O, and to a lesser extent N play a vital role over a large region of parameter space, while S and Ar opacities are negligible. The variation of the average electron temperature T(e) of the models with metal abundance, density, and T(eff) is investigated. It is concluded that by far the most important determinator of T(e) is metal abundance; an almost 7000 K difference is expected over the factor of 10 change from up to down abundances.

Capsule implosions for continuum x-ray backlighting of opacity samples at the National Ignition Facility

DOE PAGES

Opachich, Y. P.; Heeter, R. F.; Barrios, M. A.; ...

2017-06-08

Direct drive implosions of plastic capsules have been performed at the National Ignition Facility to provide a broad-spectrum (500–2000 eV) X-ray continuum source for X-ray transmission spectroscopy. The source was developed for the high-temperature plasma opacity experimental platform. Initial experiments using 2.0 mm diameter polyalpha-methyl styrene capsules with ~20 μm thickness have been performed. X-ray yields of up to ~1 kJ/sr have been measured using the Dante multichannel diode array. The backlighter source size was measured to be ~100 μm FWHM, with ~350 ps pulse duration during the peak emission stage. Lastly, these results are used to simulate transmission spectramore » for a hypothetical iron opacity sample at 150 eV, enabling the derivation of photometrics requirements for future opacity experiments.« less

Capsule implosions for continuum x-ray backlighting of opacity samples at the National Ignition Facility.

PubMed

Opachich, Y P; Heeter, R F; Barrios, M A; Garcia, E M; Craxton, R S; King, J A; Liedahl, D A; McKenty, P W; Schneider, M B; May, M J; Zhang, R; Ross, P W; Kline, J L; Moore, A S; Weaver, J L; Flippo, K A; Perry, T S

2017-06-01

Direct drive implosions of plastic capsules have been performed at the National Ignition Facility to provide a broad-spectrum (500-2000 eV) X-ray continuum source for X-ray transmission spectroscopy. The source was developed for the high-temperature plasma opacity experimental platform. Initial experiments using 2.0 mm diameter polyalpha-methyl styrene capsules with ∼20  μ m thickness have been performed. X-ray yields of up to ∼1 kJ/sr have been measured using the Dante multichannel diode array. The backlighter source size was measured to be ∼100  μ m FWHM, with ∼350 ps pulse duration during the peak emission stage. Results are used to simulate transmission spectra for a hypothetical iron opacity sample at 150 eV, enabling the derivation of photometrics requirements for future opacity experiments.

The Iron Project & Opacity Project: Photoionization, radiative transitions of iron ions for Opacities and Astrophysical Applications

NASA Astrophysics Data System (ADS)

Zhao, Lianshui; Nahar, Sultana; Pradhan, Anil; Eissner, Werner

2017-04-01

We have carried out converged close coupling R-Matrix (CCC-RM) calculations for photoionization of Ne-like Fe XVII and demonstrate orders-of-magnitude enhancements in cross section due to successive core excitations. Convergence criteria are: (i) inclusion of sufficient number of residual ion Fe XVIII core states, (ii) high-resolution of myriad autoionizing resonances, and (iii) high-energy cross sections. We discuss verification of the conventional oscillator strength sum-rule in limited energy regions for bound-free plasma opacity. High energy cross sections are also under investigation. In order to obtain solar iron opacity at the boundary of the radiative and convection zones, we have studied the residual ion states that should provide convergence of resonances of other L-shell iron ions, Fe XIV - Fe XX, in the plasma region. Preliminary results from R-matrix calculations of photoionization cross sections will be reported. NSF, DOE, OSC.

Helioseismic and neutrino data-driven reconstruction of solar properties

NASA Astrophysics Data System (ADS)

Song, Ningqiang; Gonzalez-Garcia, M. C.; Villante, Francesco L.; Vinyoles, Nuria; Serenelli, Aldo

2018-06-01

In this work, we use Bayesian inference to quantitatively reconstruct the solar properties most relevant to the solar composition problem using as inputs the information provided by helioseismic and solar neutrino data. In particular, we use a Gaussian process to model the functional shape of the opacity uncertainty to gain flexibility and become as free as possible from prejudice in this regard. With these tools we first readdress the statistical significance of the solar composition problem. Furthermore, starting from a composition unbiased set of standard solar models (SSMs) we are able to statistically select those with solar chemical composition and other solar inputs which better describe the helioseismic and neutrino observations. In particular, we are able to reconstruct the solar opacity profile in a data-driven fashion, independently of any reference opacity tables, obtaining a 4 per cent uncertainty at the base of the convective envelope and 0.8 per cent at the solar core. When systematic uncertainties are included, results are 7.5 per cent and 2 per cent, respectively. In addition, we find that the values of most of the other inputs of the SSMs required to better describe the helioseismic and neutrino data are in good agreement with those adopted as the standard priors, with the exception of the astrophysical factor S11 and the microscopic diffusion rates, for which data suggests a 1 per cent and 30 per cent reduction, respectively. As an output of the study we derive the corresponding data-driven predictions for the solar neutrino fluxes.

Spectroscopic Infrared Extinction Mapping as a Probe of Grain Growth in IRDCs

NASA Astrophysics Data System (ADS)

Lim, Wanggi; Carey, Sean J.; Tan, Jonathan C.

2015-11-01

We present spectroscopic tests of MIR to FIR extinction laws in IRDC G028.36+00.07, a potential site of massive star and star cluster formation. Lim & Tan developed methods of FIR extinction mapping of this source using Spitzer-MIPS 24 μm and Herschel-PACS 70 μm images, and by comparing to MIR Spitzer-IRAC 3-8 μm extinction maps, found tentative evidence for grain growth in the highest mass surface density regions. Here we present results of spectroscopic infrared extinction mapping using Spitzer-IRS (14-38 μm) data of the same Infrared dark cloud (IRDC). These methods allow us to first measure the SED of the diffuse Galactic interstellar medium that is in the foreground of the IRDC. We then carry out our primary investigation of measuring the MIR to FIR opacity law and searching for potential variations as a function of mass surface density within the IRDC. We find relatively flat, featureless MIR-FIR opacity laws that lack the ˜12 and ˜35 μm features associated with the thick water ice mantle models of Ossenkopf & Henning. Their thin ice mantle models and the coagulating aggregate dust models of Ormel et al. are a generally better match to the observed opacity laws. We also find evidence for generally flatter MIR to FIR extinction laws as mass surface density increases, strengthening the evidence for grain and ice mantle growth in higher density regions.

SPECTROSCOPIC INFRARED EXTINCTION MAPPING AS A PROBE OF GRAIN GROWTH IN IRDCs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lim, Wanggi; Carey, Sean J.; Tan, Jonathan C.

We present spectroscopic tests of MIR to FIR extinction laws in IRDC G028.36+00.07, a potential site of massive star and star cluster formation. Lim and Tan developed methods of FIR extinction mapping of this source using Spitzer-MIPS 24 μm and Herschel-PACS 70 μm images, and by comparing to MIR Spitzer-IRAC 3–8 μm extinction maps, found tentative evidence for grain growth in the highest mass surface density regions. Here we present results of spectroscopic infrared extinction mapping using Spitzer-IRS (14–38 μm) data of the same Infrared dark cloud (IRDC). These methods allow us to first measure the SED of the diffusemore » Galactic interstellar medium that is in the foreground of the IRDC. We then carry out our primary investigation of measuring the MIR to FIR opacity law and searching for potential variations as a function of mass surface density within the IRDC. We find relatively flat, featureless MIR–FIR opacity laws that lack the ∼12 and ∼35 μm features associated with the thick water ice mantle models of Ossenkopf and Henning. Their thin ice mantle models and the coagulating aggregate dust models of Ormel et al. are a generally better match to the observed opacity laws. We also find evidence for generally flatter MIR to FIR extinction laws as mass surface density increases, strengthening the evidence for grain and ice mantle growth in higher density regions.« less

Molar-incisor hypomineralization (MIH) in a group of school-aged children in Benghazi, Libya.

PubMed

Fteita, D; Ali, A; Alaluusua, S

2006-06-01

Molar-incisor hypomineralization (MIH) is common in many countries and it has significant impact on treatment need. The aim of the present study was to assess developmental enamel defects with an emphasis to MIH in children from four primary schools in Benghazi, Libya. Permanent first molars of a total of 378 (188 females) 7.0-8.9-year-old children were examined for demarcated opacities, diffuse opacities and hypoplasia in their schools using a portable light, a mirror, and a probe. A subgroup of children attending two of the four schools and having all incisors and first molars erupted (N = 154) was examined for enamel defects in these teeth. Eleven children (2.9%) had MIH. The mean value of demarcated opacities in their first molars was 1.5. MIH lesions were found only in 1.1% of the children's first molars (tooth prevalence) and all lesions were mild. Six children (1.6%) had diffuse opacities and 3 (0.8%) had hypoplastic defects in their first molars. Fourteen out of 154 children (9%) who had both incisors and molars examined had some kind of developmental enamel defect: 11 children (7.1%) had demarcated opacities, 3 (1.9%) had diffuse opacities, and none had hypoplasia. MIH was rare in Benghazi, Libya. The prevalence was clearly lower than in comparable studies performed in Italy or in Nordic countries, where, according to the earlier reports, MIH is seen in every fifth or sixth child. Our result may be valuable when so far mostly unknown etiology behind MIH is investigated.

Laboratory Measurements of Sulfuric Acid Vapor Opacity at Millimeter Wavelengths Under Venus Conditions

NASA Astrophysics Data System (ADS)

Akins, Alexander Brooks; Steffes, Paul G.

2017-10-01

Radio astronomical observations of the lower-cloud and sub-cloud regions of the Venusian atmosphere at millimeter wavelengths can provide insight into the nature of the sub-cloud sulfur chemistry. Previous observations (de Pater et al., Icarus 90, 1991 and Sagawa, J. Natl. Inst. of Inf. And Comm. Tech. 55, 2008) indicate substantial variations in Venus disc brightness at millimeter wavelengths, likely due to variations in SO2 and H2SO4 vapor abundances. Although previous measurements of H2SO4 vapor opacity provide accurate information at centimeter wavelengths (Kolodner and Steffes, Icarus 132, 1998), extrapolation to millimeter wavelength observations is speculative. A Fabry-Perot open resonator with a quality factor in excess of 15,000 has been designed to measure the opacity of H2SO4 vapor in a CO2 atmosphere under Venus temperature and pressure conditions below the clouds. The resonator system has been designed using corrosion-resistant materials to ensure data integrity. Opacity measurements made with this system target the 2-4 millimeter wavelength range, applicable to recent Atacama Large Millimeter Array observations of Venus. Initial laboratory results for H2SO4 vapor opacity will be presented, and the implications of these results for pressure broadened opacity formalisms will be discussed. In addition to radio astronomical observations, these results of these measurements can aid in the interpretation of radiometer and radio occultation measurements from future Venus missions, such as the Venera D orbiter. This work is supported by the NASA Solar System Workings Program under grant NNX17AB19G.

Quantitative determination of radio-opacity: equivalence of digital and film X-ray systems.

PubMed

Nomoto, R; Mishima, A; Kobayashi, K; McCabe, J F; Darvell, B W; Watts, D C; Momoi, Y; Hirano, S

2008-01-01

To evaluate the equivalence of a digital X-ray system (DenOptix) to conventional X-ray film in terms of the measured radio-opacity of known filled-resin materials and the suitability of attenuation coefficient for radio-opacity determination. Discs of five thicknesses (0.5-2.5mm) and step-wedges of each of three composite materials of nominal aluminum-equivalence of 50%, 200% and 450% were used. X-ray images of a set of discs (or step-wedge), an aluminum step-wedge, and a lead block were taken at 65 kV and 10 mA at a focus-film distance of 400 mm for 0.15s and 1.6s using an X-ray film or imaging plate. Radio-opacity was determined as equivalent aluminum thickness and attenuation coefficient. The logarithm of the individual optical density or gray scale value, corrected for background, was plotted against thickness, and the attenuation coefficient determined from the slope. The method of ISO 4049 was used for equivalent aluminum thickness. The equivalent aluminum thickness method is not suitable for materials of low radio-opacity, while the attenuation coefficient method could be used for all without difficulty. The digital system gave attenuation coefficients of greater precision than did film, but the use of automatic gain control (AGC) distorted the outcome unusably. Attenuation coefficient is a more precise and generally applicable approach to the determination of radio-opacity. The digital system was equivalent to film but with less noise. The use of AGC is inappropriate for such determinations.

Vector correlation between the alignment of reactant N2 (A 3Σu+) and the alignment of product NO (A 2Σ+) rotation in the energy transfer reaction of aligned N2 (A 3Σu+) + NO (X 2Π) → NO (A 2Σ+) + N2 (X 1Σg+).

PubMed

Ohoyama, H

2013-12-21

The vector correlation between the alignment of reactant N2 (A (3)Σu(+)) and the alignment of product NO (A (2)Σ(+)) rotation has been studied in the energy transfer reaction of aligned N2 (A (3)Σu(+)) + NO (X (2)Π) → NO (A (2)Σ(+)) + N2 (X (1)Σg(+)) under the crossed beam condition at a collision energy of ~0.07 eV. NO (A (2)Σ(+)) emission in the two linear polarization directions (i.e., parallel and perpendicular with respect to the relative velocity vector v(R)) has been measured as a function of the alignment of N2 (A (3)Σu(+)) along its molecular axis in the collision frame. The degree of polarization of NO (A (2)Σ(+)) emission is found to depend on the alignment angle (θ(v(R))) of N2 (A (3)Σu(+)) in the collision frame. The shape of the steric opacity function at the two polarization conditions turns out to be extremely different from each other: The steric opacity function at the parallel polarization condition is more favorable for the oblique configuration of N2 (A (3)Σu(+)) at an alignment angle of θ(v(R)) ~ 45° as compared with that at the perpendicular polarization condition. The alignment of N2 (A (3)Σu(+)) is found to give a significant effect on the alignment of NO (A (2)Σ(+)) rotation in the collision frame: The N2 (A (3)Σu(+)) configuration at an oblique alignment angle θ(v(R)) ~ 45° leads to a parallel alignment of NO (A (2)Σ(+)) rotation (J-vector) with respect to v(R), while the axial and sideways configurations of N2 (A (3)Σu(+)) lead to a perpendicular alignment of NO (A (2)Σ(+)) rotation with respect to vR. These stereocorrelated alignments of the product rotation have a good correlation with the stereocorrelated reactivity observed in the multi-dimensional steric opacity function [H. Ohoyama and S. Maruyama, J. Chem. Phys. 137, 064311 (2012)].

Patchy intergalactic He II absorption in HE 2347-4342. II. The possible discovery of the epoch of He-reionization

NASA Astrophysics Data System (ADS)

Reimers, D.; Kohler, S.; Wisotzki, L.; Groote, D.; Rodriguez-Pascual, P.; Wamsteker, W.

1997-11-01

We report on observations of redshifted Heii303.8 Angstroms absorption in the high-redshift QSO HE2347-4342 (z=2.885, V=16.1) with the Goddard High Resolution Spectrograph on board HST in its low resolution mode (bigtriangleup lambda = 0.7 Angstroms). With f_λ=3.6\\ 10(-15) ergcm(-2) s(-1) Angstroms(-1) at the expected position of Heii304 Angstroms absorption it is the most UV-bright high redshift QSO discovered so far. We show that the Heii opacity as a function of redshift is patchy showing spectral regions with low Heii opacity (``voids'') and regions with high Heii opacity (blacked-out ``troughs'') and no detectable flux. Combination with high-resolution optical spectra of the Lyalpha forest using CASPEC at the 3.6m telescope shows that the voids can be explained either exclusively by Lyalpha forest cloud absorption with a moderate N_{subs {He{sc ii}}}/N_{subs {H{sc i}}} ratio eta <=100 and turbulent line broadening or by a combination of Lyalpha forest with eta = 45 and thermal broadening plus a diffuse medium with tau_ {subs {GP}}({subs {He{sc ) ii}}} ~ 0.3. Since the latter is a minimum assumption for the Lyalpha forest, a strict upper limit to a diffuse medium is Omega_ {subs {diff}}<0.02 h50(-1.5) at z=2.8. In the troughs in addition to the Lyalpha forest opacity a continuous Heii 304 Angstroms opacity tau = 4.8(+infty }_{-2) is required. In case of photoionization, the troughs would require a diffuse component with a density close to Omega =~ 0.077(eta /45)(-0.5) h50(-1.5) , i.e. all baryons in the universe, which is inconsistent, however, with the observed absence of such a component in the voids. A tentative interpretation is that we observe the epoch of partial Heii reionization of the universe with patches not yet reionized. In that case a diffuse component with Omega_ {subs {diff}}>= 1.3\\ 10(-4) h(-1}_{50) would be sufficient to explain the ``trough'' opacity. The size of the 1163--1172 Angstroms trough is ~ 6 h50(-1) Mpc or ~ 2300 kms(-1) , respectively. We also discuss partially resolved Heii absorption of a high-ionization associated absorption system. Despite its high luminosity HE2347-4342 does not show a Heii proximity effect. A possible reason is that the strong associated system shields the Heii ionizing continuum. Based on observations collected at the European Southern Observatory, La Silla, Chile (ESO No.\\ 58.B--0116). Based on IUE observations collected at the ESA VILSPA ground station near Madrid, Spain. Based on observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by Aura, Inc., under NASA contract NAS 5--26\\,555.

Transient Asymptomatic Pulmonary Opacities Occurring during Osimertinib Treatment.

PubMed

Noonan, Sinead A; Sachs, Peter B; Camidge, D Ross

2016-12-01

Osimertinib is an EGFR inhibitor licensed for the treatment of EGFR-mutant, T790M-positive NSCLC. Previously unreported, frequent transient asymptomatic pulmonary opacities were noted in patients during osimertinib therapy at the University of Colorado. Computed tomography imaging and clinical notes on patients with NSCLC who had been treated with osimertinib at the University of Colorado were retrospectively reviewed. Transient asymptomatic pulmonary opacities developed in seven of 20 patients (35%) while they were receiving osimertinib. The radiological patterns seen included ground-glass opacities with or without nodular consolidation. The median time to development of the first lesion was 8.7 weeks (range 1.6-43 weeks), the median time to resolution during continued osimertinib was 6 weeks (range 1-11 weeks). Transient asymptomatic pulmonary opacities may be a previously unrecognized, benign feature associated with osimertinib therapy that may be mistaken for isolated pulmonary progression or the beginning of more severe pneumonitis. If new-onset pulmonary lesions, especially those associated with ground-glass appearances, are asymptomatic and localized and there is no evidence of disease progression elsewhere, it may be reasonable to continue treatment with osimertinib and monitor the lesions for resolution. Copyright © 2016 International Association for the Study of Lung Cancer. Published by Elsevier Inc. All rights reserved.

Color and opacity of composites protected with surface sealants and submitted to artificial accelerated aging.

PubMed

Aguilar, Fabiano Gamero; Roberti Garcia, Lucas da Fonseca; Cruvinel, Diogo Rodrigues; Sousa, Ana Beatriz Silva; de Carvalho Panzeri Pires-de-Souza, Fernanda

2012-01-01

To evaluate the color similarity, stability and opacity of composites (TPH, Charisma, and Concept, shade A2) protected with surface sealants (Fortify Plus and Biscover) and cyanoacrylate (Super Bonder). Forty specimens of each composite were made and separated into 4 groups (n=10) according to the surface protection: GI - without sealant; GII - cyanoacrylate; GIII - Fortify Plus; GIV - Biscover. Color and opacity readings were taken before and after Artificial Acelerated Aging (AAA) and the values obtained for color stability were submitted to statistical analysis by 2-way ANOVA and Bonferroni's test (P<.05). The values acquired for color similarity were submitted to 1-way ANOVA and Tukey's test (P<.05). The specimen sufaces were compared before and after AAA using Scanning Electronic Microscopy (SEM). Studied composites did not present the same values for the coordinates L*, a* and b * before AAA, indicating that there was no color similarity among them. All composites presented color alteration after AAA with clinically unacceptable values. Protected groups presented lower opacity variation after AAA, in comparison with the control goup. SEM evaluation demonstrated that AAA increased the surface irregularities in all of the studied groups. Surface sealants were not effective in maintaining composite color, but were able to maintain opacity.

The Error Structure of the SMAP Single and Dual Channel Soil Moisture Retrievals

NASA Astrophysics Data System (ADS)

Dong, Jianzhi; Crow, Wade T.; Bindlish, Rajat

2018-01-01

Knowledge of the temporal error structure for remotely sensed surface soil moisture retrievals can improve our ability to exploit them for hydrologic and climate studies. This study employs a triple collocation analysis to investigate both the total variance and temporal autocorrelation of errors in Soil Moisture Active and Passive (SMAP) products generated from two separate soil moisture retrieval algorithms, the vertically polarized brightness temperature-based single-channel algorithm (SCA-V, the current baseline SMAP algorithm) and the dual-channel algorithm (DCA). A key assumption made in SCA-V is that real-time vegetation opacity can be accurately captured using only a climatology for vegetation opacity. Results demonstrate that while SCA-V generally outperforms DCA, SCA-V can produce larger total errors when this assumption is significantly violated by interannual variability in vegetation health and biomass. Furthermore, larger autocorrelated errors in SCA-V retrievals are found in areas with relatively large vegetation opacity deviations from climatological expectations. This implies that a significant portion of the autocorrelated error in SCA-V is attributable to the violation of its vegetation opacity climatology assumption and suggests that utilizing a real (as opposed to climatological) vegetation opacity time series in the SCA-V algorithm would reduce the magnitude of autocorrelated soil moisture retrieval errors.

Spectrally resolved opacities and Rosseland and Planck mean opacities of lowly ionized gold plasmas: a detailed level-accounting investigation.

PubMed

Zeng, Jiaolong; Yuan, Jianmin

2007-08-01

Calculation details of radiative opacity for lowly ionized gold plasmas by using our developed fully relativistic detailed level-accounting approach are presented to show the importance of accurate atomic data for a quantitative reproduction of the experimental observations. Even though a huge number of transition lines are involved in the radiative absorption of high- Z plasmas so that one believes that statistical models can often give a reasonable description of their opacities, we first show in detail that an adequate treatment of physical effects, in particular the configuration interaction (including the core-valence electron correlation), is essential to produce atomic data of bound-bound and bound-free processes for gold plasmas, which are accurate enough to correctly explain the relative intensity of two strong absorption peaks experimentally observed located near photon energy of 70 and 80 eV. A detailed study is also carried out for gold plasmas of an average ionization degree sequence of 10, for both spectrally resolved opacities and Rosseland and Planck means. For comparison, results obtained by using an average atom model are also given to show that even for a relatively higher density of matter, correlation effects are also important to predict the correct positions of absorption peaks of transition arrays.

Toxic Inhalational Injury-Associated Interstitial Lung Disease in Children

PubMed Central

Lee, Eun; Seo, Ju-Hee; Kim, Hyung Young; Yu, Jinho; Jhang, Won-Kyoung; Park, Seong-Jong; Kwon, Ji-Won; Kim, Byoung-Ju; Do, Kyung-Hyun; Cho, Young Ah; Kim, Sun-A; Jang, Se Jin

2013-01-01

Interstitial lung disease in children (chILD) is a group of disorders characterized by lung inflammation and interstitial fibrosis. In the past recent years, we noted an outbreak of child in Korea, which is possibly associated with inhalation toxicity. Here, we report a series of cases involving toxic inhalational injury-associated chILD with bronchiolitis obliterans pattern in Korean children. This study included 16 pediatric patients confirmed by lung biopsy and chest computed tomography, between February 2006 and May 2011 at Asan Medical Center Children's Hospital. The most common presenting symptoms were cough and dyspnea. The median age at presentation was 26 months (range: 12-47 months), with high mortality (44%). Histopathological analysis showed bronchiolar destruction and centrilobular distribution of alveolar destruction by inflammatory and fibroproliferative process with subpleural sparing. Chest computed tomography showed ground-glass opacities and consolidation in the early phase and diffuse centrilobular nodular opacity in the late phase. Air leak with severe respiratory difficulty was associated with poor prognosis. Although respiratory chemicals such as humidifier disinfectants were strongly considered as a cause of this disease, further studies are needed to understand the etiology and pathophysiology of the disease to improve the prognosis and allow early diagnosis and treatment. PMID:23772158

The corneal fibrosis response to epithelial-stromal injury

PubMed Central

Torricelli, Andre A. M.; Santhanam, Abirami; Wu, Jiahui; Singh, Vivek; Wilson, Steven E.

2014-01-01

The corneal wound healing response, including the development of stromal opacity in some eyes, is a process that often leads to scarring that occurs after injury, surgery or infection to the cornea. Immediately after epithelial and stromal injury, a complex sequence of processes contributes to wound repair and regeneration of normal corneal structure and function. In some corneas, however, often depending on the type and extent of injury, the response may also lead to the development of mature vimentin+ α-smooth muscle actin+ desmin+ myofibroblasts. Myofibroblasts are specialized fibroblastic cells generated in the cornea from keratocyte-derived or bone marrow-derived precursor cells. The disorganized extracellular matrix components secreted by myofibroblasts, in addition to decreased expression of corneal crystallins in these cells, are central biological processes that result in corneal stromal fibrosis associated with opacity or “haze”. Several factors are associated with myofibroblast generation and haze development after PRK surgery in rabbits, a reproducible model of scarring, including the amount of tissue ablated, which may relate to the extent of keratocyte apoptosis in the early response to injury, irregularity of stromal surface after surgery, and changes on corneal stromal proteoglycans, but normal regeneration of the epithelial basement membrane (EBM) appears to be a critical factor determining whether a cornea heals with relative transparency or vision-limiting stromal opacity. Structural and functional abnormalities of the regenerated EBM facilitate prolonged entry of epithelium-derived growth factors such as transforming growth factor β (TGF-β) and platelet-derived growth factor (PDGF) into the stroma that both drive development of mature myofibroblasts from precursor cells and lead to persistence of the cells in the anterior stroma. A major discovery that has contributed to our understanding of haze development is that keratocytes and corneal fibroblasts, but not myofibroblasts, produce large amounts of critical EBM components, such as nidogen-1, nidogen-2 and perlecan, that are essential for complete regeneration of a normal EBM once laminin secreted by epithelial cells self-polymerizes into a nascent EBM. Mature myofibroblasts that become established in the anterior stroma are a barrier to keratocyte contributions to the nascent EBM. These myofibroblasts, and the opacity they produce, often persist for months or years after the injury. Transparency is subsequently restored when the EBM is completely regenerated, myofibroblasts are deprived of TGFβ and undergo apoptosis, and the keratocytes re-occupy the anterior stroma and reabsorb disordered extracellular matrix. The aim of this review is to highlight factors involved in the generation of stromal haze and its subsequent removal. PMID:26675407

Library OPACs on the Web: Finding and Describing Directories.

ERIC Educational Resources Information Center

Henry, Marcia

1997-01-01

Provides current descriptions of some of the major directories that link to library catalogs on the World Wide Web. Highlights include LibWeb; Hytelnet; WebCats; WWW Library Directory; and techniques for finding new library OPAC (online public access catalog) directories. (LRW)

Colour stability and opacity of resin cements and flowable composites for ceramic veneer luting after accelerated ageing.

PubMed

Archegas, Lucí Regina Panka; Freire, Andrea; Vieira, Sergio; Caldas, Danilo Biazzetto de Menezes; Souza, Evelise Machado

2011-11-01

Colour changes of the luting material can become clinically visible affecting the aesthetic appearance of thin ceramic laminates. The aim of this in vitro study was to evaluate the colour stability and opacity of light- and dual-cured resin cements and flowable composites after accelerated ageing. The luting agents were bonded (0.2 mm thick) to ceramic disks (0.75 mm thick) built with the pressed-ceramic IPS Aesthetic Empress (n=7). Colour measurements were determined using a FTIR spectrophotometer before and after accelerated ageing in a weathering machine with a total energy of 150 kJ. Changes in colour (ΔE) and opacity (ΔO) were obtained using the CIE L*a*b* system. The results were submitted to one-way ANOVA, Tukey HSD test and Student's t test (α=5%). All the materials showed significant changes in colour and opacity. The ΔE of the materials ranged from 0.41 to 2.40. The highest colour changes were attributed to RelyX ARC and AllCem, whilst lower changes were found in Variolink Veneer, Tetric Flow and Filtek Z350 Flow. The opacity of the materials ranged from -0.01 to 1.16 and its variation was not significant only for Opallis Flow and RelyX ARC. The accelerated ageing led to colour changes in all the evaluated materials, although they were considered clinically acceptable (ΔE<3). Amongst the dual-cured resin cements, Variolink II demonstrated the highest colour stability. All the flowable composites showed proper colour stability for the luting of ceramic veneers. After ageing, an increase in opacity was observed for most of the materials. Copyright © 2011 Elsevier Ltd. All rights reserved.

WVR-GPS comparison measurements and calibration of the 20-32 GHz tropospheric water vapor absorption model.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Keihm, S. J.; Bar-Server, Y.; Liljegren, J. C.

2002-06-01

Collocated measurements of opacity (from water vapor radiometer brightness temperatures) and wet path delay (from ground-based tracking of global positioning satellites) are used to constrain the model of atmospheric water vapor absorption in the 20-32 GHz band. A differential approach is presented in which the slope of opacity-versus-wet delay data is used as the absorption model constraint. This technique minimizes the effects of radiometric calibration errors and oxygen model uncertainties in the derivation of a best-fit vapor absorption model. A total of approximately five months of data was obtained from two experiment sites. At the Cloud and Radiation Testbed (CART)more » site near Lamont, Oklahoma, three independent water vapor radiometers (WVRs) provided near-continuous opacity measurements over the interval July-September 1998. At the NASA/Goldstone tracking station in the California desert two WVRs; obtained opacity data over the September-October 1997 interval. At both sites a Global Positioning Satellite (GPS) receiver and surface barometer obtained the data required for deriving the zenith wet delays over the same time frames. Measured values of the opacity-versus-wet delay slope parameter were obtained at four WVR frequencies (20.7, 22.2, 23.8, and 31.4 GHz) and compared with predictions of four candidate absorption models referenced in the literature. With one exception, all three models provide agreement within 5% of the opacity-versus-wet delay slope measurements at all WVR frequencies at both sites. One model provides agreement for all channels at both sites to the 2-3% level. This absorption model accuracy level represents a significant improvement over that attainable using radiosondes.« less

40 CFR 61.177 - Reporting requirements.

Code of Federal Regulations, 2010 CFR

2010-07-01

...) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS National Emission Standard for Inorganic Arsenic... opacity level determination required in § 61.175(c) to afford the Administrator the opportunity to have an... normally during the reference opacity level determination; and (3) A written report each quarter of each...

40 CFR 61.177 - Reporting requirements.

Code of Federal Regulations, 2011 CFR

2011-07-01

...) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS National Emission Standard for Inorganic Arsenic... opacity level determination required in § 61.175(c) to afford the Administrator the opportunity to have an... normally during the reference opacity level determination; and (3) A written report each quarter of each...

OPAC Missing Record Retrieval.

ERIC Educational Resources Information Center

Johnson, Karl E.

1996-01-01

When the Higher Education Library Information Network of Rhode Island transferred members' bibliographic data into a shared online public access catalog (OPAC), 10% of the University of Rhode Island's monograph records were missing. This article describes the consortium's attempts to retrieve records from the database and the effectiveness of…

Web-based OPACs: Between Tradition and Innovation.

ERIC Educational Resources Information Center

Moscoso, Purificacion; Ortiz-Repiso, Virginia

1999-01-01

Analyzes the change that Internet-based OPACs (Online Public Access Catalogs) have represented to the structure, administration, and maintenance of the catalogs, retrieval systems, and user interfaces. Examines the structure of databases and traditional principles that have governed systems development. Discusses repercussions of the application…

Uranium Workers Demonstrate Lower Lobe Predominant Irregular Pneumoconiotic Opacities on Chest Radiographs.

PubMed

Kocher, Elizabeth; Rendon, Kristi J; Kesler, Denece; Boyce, Tawny Wilson; Myers, Orrin; Evans, Kandace; Cook, Linda S; Sood, Akshay

2016-01-01

There is a paucity of literature on the chest radiographic findings in uranium workers. To characterize the chest radiographic findings of pneumoconiosis in a New Mexican cohort of uranium workers. The most recent results from chest radiographs were abstracted in this cross-sectional study. Radiographs showed small pneumoconiotic opacities of profusion score of ≥ 1/0 in 155/429 (36.1%) uranium workers. The most common shape/size of the primary and secondary opacities was s (90.3%) and t (83.7%) types, respectively. Lower lung zones were the most affected. American Indians were the population group at greatest odds for having profusion score ≥ 1/0 (O.R. 2.65, 95% C.I. 1.61, 4.36). Uranium workers' pneumoconiosis is associated with predominantly lower lobe, irregular, and small opacities. Clinical providers and policymakers must consider uranium workers' pneumoconiosis in the differential diagnosis for lower lobe-predominant interstitial lung disease, in the appropriate exposure setting.

Studying effects of non-equilibrium radiative transfer via HPC

DOE Office of Scientific and Technical Information (OSTI.GOV)

Holladay, Daniel

This report presents slides on Ph.D. Research Goals; Local Thermodynamic Equilibrium (LTE) Implications; Calculating an Opacity; Opacity: Pictographic Representation; Opacity: Pictographic Representation; Opacity: Pictographic Representation; Collisional Radiative Modeling; Radiative and Collisional Excitation; Photo and Electron Impact Ionization; Autoionization; The Rate Matrix; Example: Total Photoionization rate; The Rate Coefficients; inlinlte version 1.1; inlinlte: Verification; New capabilities: Rate Matrix – Flexibility; Memory Option Comparison; Improvements over previous DCA solver; Inter- and intra-node load balancing; Load Balance – Full Picture; Load Balance – Full Picture; Load Balance – Internode; Load Balance – Scaling; Description; Performance; xRAGE Simulation; Post-process @ 2hr; Post-process @ 4hr;more » Post-process @ 8hr; Takeaways; Performance for 1 realization; Motivation for QOI; Multigroup Er; Transport and NLTE large effects (1mm, 1keV); Transport large effect, NLTE lesser (1mm, 750eV); Blastwave Diagnostici – Description & Performance; Temperature Comparison; NLTE has effect on dynamics at wall; NLTE has lesser effect in the foam; Global Takeaways; The end.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nagayama, T.; Bailey, J. E.; Loisel, G. P.

Iron opacity calculations presently disagree with measurements at an electron temperature of ~180–195 eV and an electron density of (2–4)×10 22cm –3, conditions similar to those at the base of the solar convection zone. The measurements use x rays to volumetrically heat a thin iron sample that is tamped with low-Z materials. The opacity is inferred from spectrally resolved x-ray transmission measurements. Plasma self-emission, tamper attenuation, and temporal and spatial gradients can all potentially cause systematic errors in the measured opacity spectra. In this article we quantitatively evaluate these potential errors with numerical investigations. The analysis exploits computer simulations thatmore » were previously found to reproduce the experimentally measured plasma conditions. The simulations, combined with a spectral synthesis model, enable evaluations of individual and combined potential errors in order to estimate their potential effects on the opacity measurement. Lastly, the results show that the errors considered here do not account for the previously observed model-data discrepancies.« less

Estimates of the Tropospheric Vertical Structure of Neptune Based on Microwave Radiative Transfer Studies

NASA Technical Reports Server (NTRS)

DeBoer, David R.; Steffes, Paul G.

1996-01-01

A radiative transfer model incorporating, among other things, the recently measured centimeter wavelength opacity of H2S, the full line catalog of PH3, and absorption due to CO has been developed to study the tropospheric vertical structure of Neptune. To match radio-telescope observations, subsolar amounts of NH3 and supersolar amounts of H2S are found to be needed, as has been previously noted. To match both the measured microwave emission and the measured opacity at 13 cm and 6.3 bars by Voyager 2, an H2S dominant atmosphere (H2S/NH3 approximately equals 40) with enhanced PH3 (15 x solar) or NH3 supersaturation with respect to the putative NH4SH cloud (400 ppbv) seems to be indicated. Due to the possible importance of PH3 opacity, it is suggested that measurements of its opacity could aid in resolving some of the outstanding ambiguities concerning Neptune's tropospheric structure.

Iron and molecular opacities and the evolution of Population I stars

NASA Technical Reports Server (NTRS)

Stothers, Richard B.; Chin, Chao-Wen

1993-01-01

Effects of recent opacity revisions on the evolution of Population I stars are explored over the range 1.5-60 solar masses. Opacity parameters considered include the angular momentum coupling scheme for iron, the relative iron abundance, the total metal abundance, and diatomic and triatomic molecular sources. Only the total metal abundance exerts an important control over the evolutionary tracks. Blue loops on the H-R diagram during core helium burning can be very sensitive to opacity, but only insofar as the simple formation or suppression of a blue loop is concerned. The blue loops are most robust for stellar masses around 10 solar masses. We confirm, from a comparison of stellar models with observational data, that the total metal abundance is close to solar and that convective core overshooting is likely to be very slight. The new models predict the existence of an iron convection zone in the envelope and a great widening of the main-sequence band in the H-R diagram at luminosities brighter than 100,000 solar luminosities.

Simulations of the National Ignition Facility Opacity Sample

NASA Astrophysics Data System (ADS)

Martin, M. E.; London, R. A.; Heeter, R. F.; Dodd, E. S.; Devolder, B. G.; Opachich, Y. P.; Liedahl, D. A.; Perry, T. S.

2017-10-01

A platform to study the opacity of high temperature materials at the National Ignition Facility has been developed. Experiments to study the opacity of materials relevant to inertial confinement fusion and stellar astrophysics are being conducted. The initial NIF experiments are focused on reaching the same plasma conditions (T >150 eV and Ne >= 7 ×1021 cm-3) , for iron, as those achieved in previous experiments at Sandia National Laboratories' (SNL) Z-facility which have shown discrepancies between opacity theory and experiment. We developed a methodology, using 1D HYDRA simulations, to study the effects of tamper thickness on the conditions of iron-magnesium samples. We heat the sample using an x-ray drive from 2D LASNEX hohlraum simulations. We also use this methodology to predict sample uniformity and expansion for comparison with experimental data. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. Lawrence Livermore National Security, LLC.

A computational approach to estimate postmortem interval using opacity development of eye for human subjects.

PubMed

Cantürk, İsmail; Özyılmaz, Lale

2018-07-01

This paper presents an approach to postmortem interval (PMI) estimation, which is a very debated and complicated area of forensic science. Most of the reported methods to determine PMI in the literature are not practical because of the need for skilled persons and significant amounts of time, and give unsatisfactory results. Additionally, the error margin of PMI estimation increases proportionally with elapsed time after death. It is crucial to develop practical PMI estimation methods for forensic science. In this study, a computational system is developed to determine the PMI of human subjects by investigating postmortem opacity development of the eye. Relevant features from the eye images were extracted using image processing techniques to reflect gradual opacity development. The features were then investigated to predict the time after death using machine learning methods. The experimental results prove that the development of opacity can be utilized as a practical computational tool to determine PMI for human subjects. Copyright © 2018 Elsevier Ltd. All rights reserved.

Comments on "Including the effects of temperature-dependent opacities in the implicit Monte Carlo algorithm" by N.A. Gentile [J. Comput. Phys. 230 (2011) 5100-5114

NASA Astrophysics Data System (ADS)

Ghosh, Karabi

2017-02-01

We briefly comment on a paper by N.A. Gentile [J. Comput. Phys. 230 (2011) 5100-5114] in which the Fleck factor has been modified to include the effects of temperature-dependent opacities in the implicit Monte Carlo algorithm developed by Fleck and Cummings [1,2]. Instead of the Fleck factor, f = 1 / (1 + βcΔtσP), the author derived the modified Fleck factor g = 1 / (1 + βcΔtσP - min [σP‧ (aTr4 - aT4)cΔt/ρCV, 0 ]) to be used in the Implicit Monte Carlo (IMC) algorithm in order to obtain more accurate solutions with much larger time steps. Here β = 4 aT3 / ρCV, σP is the Planck opacity and the derivative of Planck opacity w.r.t. the material temperature is σP‧ = dσP / dT.

Field Measurements of Particulate Matter Emissions, Carbon Monoxide, and Exhaust Opacity from Heavy-Duty Diesel Vehicles.

PubMed

Clark, Nigel N; Jarrett, Ronald P; Atkinson, Christopher M

1999-09-01

Diesel particulate matter (PM) is a significant contributor to ambient air PM 10 and PM 2.5 particulate levels. In addition, recent literature argues that submicron diesel PM is a pulmonary health hazard. There is difficulty in attributing PM emissions to specific operating modes of a diesel engine, although it is acknowledged that PM production rises dramatically with load and that high PM emissions occur during rapid load increases on turbocharged engines. Snap-acceleration tests generally identify PM associated with rapid transient operating conditions, but not with high load. To quantify the origin of PM during transient engine operation, continuous opacity measurements have been made using a Wager 650CP full flow exhaust opacity meter. Opacity measurements were taken while the vehicles were operated over transient driving cycles on a chassis dynamometer using the West Virginia University (WVU) Transportable Heavy Duty Vehicle Emissions Testing Laboratories. Data were gathered from Detroit Diesel, Cummins, Caterpillar, and Navistar heavy-duty (HD) diesel engines. Driving cycles used were the Central Business District (CBD) cycle, the WVU 5-Peak Truck cycle, the WVU 5-Mile route, and the New York City Bus (NYCB) cycle. Continuous opacity measurements, integrated over the entire driving cycle, were compared to total integrated PM mass. In addition, the truck was subjected to repeat snap-acceleration tests, and PM was collected for a composite of these snap-acceleration tests. Additional data were obtained from a fleet of 1996 New Flyer buses in Flint, MI, equipped with electronically controlled Detroit Diesel Series 50 engines. Again, continuous opacity, regulated gaseous emissions, and PM were measured. The relationship between continuous carbon monoxide (CO) emissions and continuous opacity was noted. In identifying the level of PM emissions in transient diesel engine operation, it is suggested that CO emissions may prove to be a useful indicator and may be used to apportion total PM on a continuous basis over a transient cycle. The projected continuous PM data will prove valuable in future mobile source inventory prediction.

Haze and cloud distribution in Uranus' atmosphere based on high-contrast spatially resolved polarization measurements

NASA Astrophysics Data System (ADS)

Kostogryz, Nadiia; Berdyugina, Svetlana; Gisler, Daniel; Berkefeld, Thomas

2017-04-01

In planetary atmospheres, main sources of opacity are molecular absorption and scattering on molecules, hazes and aerosols. Hence, light reflected from a planetary atmosphere can be linearly polarized. Polarization study of inner solar system planets and exoplanets is a powerful method to characterize their atmospheres, because of a wide range of observable phase angles. For outer solar system planets, observable phase angles are very limited. For instance, Uranus can only be observed up to 3.2 degrees away from conjunctions, and its disk-integrated polarization is close to zero due to the back-scattering geometry. However, resolving the disk of Uranus and measuring the center-to-limb polarization can help constraining the vertical atmospheric structure and the nature of scattering aerosols and particles. In October 2016, we carried out polarization measurements of Uranus in narrow-band filters centered at methane bands and the adjacent continuum using the GREGOR Planet Polarimeter (GPP). The GPP is a high-precision polarimeter and is mounted at the 1.5-m GREGOR solar telescope, which is suitable for observing at night. In order to reach a high spatial resolution, the instrument uses an adaptive-optics system of the telescope. To interpret our measurements, we solve the polarized radiative transfer problem taking into account different scattering and absorption opacities. We calculate the center-to-limb variation of polarization of Uranus' disk in the continuum spectrum and in methane bands. By varying the vertical distribution of haze and cloud layers, we derive the vertical structure of the best-fit Uranus atmosphere.

Ordinary Dark Matter versus Mysterious Dark Matter in Galactic Rotation

NASA Astrophysics Data System (ADS)

Gallo, C. F.; Feng, James

2008-04-01

To theoretically describe the measured rotational velocity curves of spiral galaxies, there are two different approaches and conclusions. (1) ORDINARY DARK MATTER. We assume Newtonian gravity/dynamics and successfully find (via computer) mass distributions in bulge/disk configurations that duplicate the measured rotational velocities. There is ordinary dark matter within the galactic disk towards the cooler periphery which has lower emissivity/opacity. There are no mysteries in this scenario based on verified physics. (2) MYSTERIOUS DARK MATTER. Others INaccurately assume the galactic mass distributions follow the measured light distributions, and then the measured rotational velocity curves are NOT duplicated. To alleviate this discrepancy, speculations are invoked re ``Massive Peripheral Spherical Halos of Mysterious Dark Matter.'' But NO matter has been detected in this UNtenable Halo configuration. Many UNverified ``Mysteries'' are invoked as necessary and convenient. CONCLUSION. The first approach utilizing Newtonian gravity/dynamics and searching for the ordinary mass distributions within the galactic disk simulates reality and agrees with data.

A note on the contribution of multi-photon processes to radiative opacity

NASA Astrophysics Data System (ADS)

Pain, Jean-Christophe

2018-03-01

Recently, Bailey et al. performed iron opacity measurements on the Z machine at Sandia National Laboratory in conditions close to the ones of the base of the convective zone of the Sun. Such experiments have raised questions about the physical models commonly used in opacity codes. To understand the discrepancy between experiment and theory, More et al. investigated the role of two-photon processes. In the present work we show, by simple estimate and using hydrogenic formulas, that due to the intensity of the backlight radiation seen by the sample, such processes are likely to play an important role only for highly excited states.

A preliminary theoretical line-blanketed model solar photosphere

NASA Technical Reports Server (NTRS)

Kurucz, R. L.

1974-01-01

In the theoretical approach to model-atmosphere construction, all opacities are computed theoretically and the temperature-pressure structure is determined by conservation of energy. Until recently, this has not been a very useful method for later type stars, because the line opacity was both poorly known and difficult to calculate. However, methods have now been developed that are capable of representing the line opacity well enough for construction of realistic models. A preliminary theoretical solar model is presented that produces closer agreement with observation than has been heretofore possible. The qualitative advantages and shortcomings of this model are discussued and projected improvements are outlined.

Radiological and Pathological Correlation in Anti-MDA5 Antibody-positive Interstitial Lung Disease: Rapidly Progressive Perilobular Opacities and Diffuse Alveolar Damage.

PubMed

Chino, Haruka; Sekine, Akimasa; Baba, Tomohisa; Iwasawa, Tae; Okudela, Koji; Takemura, Tamiko; Itoh, Harumi; Sato, Shinji; Suzuki, Yasuo; Ogura, Takashi

2016-01-01

We herein present the first case of rapidly progressive interstitial lung disease (RP-ILD) with anti-melanoma differentiation-associated protein 5 (MDA5) antibody evaluated by surgical lung biopsy (SLB). High-resolution CT scan revealed perilobular opacities, which rapidly became thicker and formed consolidation, resulting in remarkable loss of lung volume. Specimens taken from SLB revealed membranous organization with alveolar occlusion, dilation of alveolar ducts, and sacs with collapsed alveoli, which are typical features of diffuse alveolar damage (DAD). Rapidly progressive perilobular opacities may be characteristic of RP-ILD with anti-MDA5 antibody and DAD.

Saturn's tropospheric composition and clouds from Cassini/VIMS 4.6-5.1 μm nightside spectroscopy

NASA Astrophysics Data System (ADS)

Fletcher, Leigh N.; Baines, Kevin H.; Momary, Thomas W.; Showman, Adam P.; Irwin, Patrick G. J.; Orton, Glenn S.; Roos-Serote, Maarten; Merlet, C.

2011-08-01

The latitudinal variation of Saturn's tropospheric composition (NH 3, PH 3 and AsH 3) and aerosol properties (cloud altitudes and opacities) are derived from Cassini/VIMS 4.6-5.1 μm thermal emission spectroscopy on the planet's nightside (April 22, 2006). The gaseous and aerosol distributions are used to trace atmospheric circulation and chemistry within and below Saturn's cloud decks (in the 1- to 4-bar region). Extensive testing of VIMS spectral models is used to assess and minimise the effects of degeneracies between retrieved variables and sensitivity to the choice of aerosol properties. Best fits indicate cloud opacity in two regimes: (a) a compact cloud deck centred in the 2.5-2.8 bar region, symmetric between the northern and southern hemispheres, with small-scale opacity variations responsible for numerous narrow light/dark axisymmetric lanes; and (b) a hemispherically asymmetric population of aerosols at pressures less than 1.4 bar (whose exact altitude and vertical structure is not constrained by nightside spectra) which is 1.5-2.0× more opaque in the summer hemisphere than in the north and shows an equatorial maximum between ±10° (planetocentric). Saturn's NH 3 spatial variability shows significant enhancement by vertical advection within ±5° of the equator and in axisymmetric bands at 23-25°S and 42-47°N. The latter is consistent with extratropical upwelling in a dark band on the poleward side of the prograde jet at 41°N (planetocentric). PH 3 dominates the morphology of the VIMS spectrum, and high-altitude PH 3 at p < 1.3 bar has an equatorial maximum and a mid-latitude asymmetry (elevated in the summer hemisphere), whereas deep PH 3 is latitudinally-uniform with off-equatorial maxima near ±10°. The spatial distribution of AsH 3 shows similar off-equatorial maxima at ±7° with a global abundance of 2-3 ppb. VIMS appears to be sensitive to both (i) an upper tropospheric circulation (sensed by NH 3 and upper-tropospheric PH 3 and hazes) and (ii) a lower tropospheric circulation (sensed by deep PH 3, AsH 3 and the lower cloud deck).

A New Method for Atmospheric Correction of MRO/CRISM Data.

NASA Astrophysics Data System (ADS)

Noe Dobrea, Eldar Z.; Dressing, C.; Wolff, M. J.

2009-09-01

The Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) aboard the Mars Reconnaissance Orbiter (MRO) collects hyperspectral images from 0.362 to 3.92 μm at 6.55 nanometers/channel, and at a spatial resolution of 20 m/pixel. The 1-2.6 μm spectral range is often used to identify and map the distribution of hydrous minerals using mineralogically diagnostic bands at 1.4 μm, 1.9 μm, and 2 - 2.5 micron region. Atmospheric correction of the 2-μm CO2 band typically employs the same methodology applied to OMEGA data (Mustard et al., Nature 454, 2008): an atmospheric opacity spectrum, obtained from the ratio of spectra from the base to spectra from the peak of Olympus Mons, is rescaled for each spectrum in the observation to fit the 2-μm CO2 band, and is subsequently used to correct the data. Three important aspects are not considered in this correction: 1) absorptions due to water vapor are improperly accounted for, 2) the band-center of each channel shifts slightly with time, and 3) multiple scattering due to atmospheric aerosols is not considered. The second issue results in miss-registration of the sharp CO2 features in the 2-μm triplet, and hence poor atmospheric correction. This leads to the necessity to ratio all spectra using the spectrum of a spectrally "bland” region in each observation in order to distinguish features 1.9 μm. Here, we present an improved atmospheric correction method, which uses emission phase function (EPF) observations to correct for molecular opacity, and a discrete ordinate radiative transfer algorithm (DISORT - Stamnes et al., Appl. Opt. 27, 1988) to correct for the effects of multiple scattering. This method results in a significant improvement in the correction of the 2-μm CO2 band, allowing us to forgo the use of spectral ratios that affect the spectral shape and preclude the derivation of reflectance values in the data.

40 CFR 86.884-11 - Instrument checks.

Code of Federal Regulations, 2010 CFR

2010-07-01

... collection equipment response of zero; (3) Calibrated neutral density filters having approximately 10, 20, and 40 percent opacity shall be employed to check the linearity of the instrument. The filter(s) shall.... Filters with exposed filtering media should be checked for opacity every six months; all other filters...

40 CFR 92.122 - Smoke meter calibration.

Code of Federal Regulations, 2010 CFR

2010-07-01

... collection equipment response of zero; (b) Calibrated neutral density filters having approximately 10, 20, and 40 percent opacity shall be employed to check the linearity of the instrument. The filter(s) shall.... Filters with exposed filtering media should be checked for opacity every six months; all other filters...

40 CFR 86.884-11 - Instrument checks.

Code of Federal Regulations, 2012 CFR

2012-07-01

... collection equipment response of zero; (3) Calibrated neutral density filters having approximately 10, 20, and 40 percent opacity shall be employed to check the linearity of the instrument. The filter(s) shall.... Filters with exposed filtering media should be checked for opacity every six months; all other filters...

40 CFR 92.122 - Smoke meter calibration.

Code of Federal Regulations, 2013 CFR

2013-07-01

... collection equipment response of zero; (b) Calibrated neutral density filters having approximately 10, 20, and 40 percent opacity shall be employed to check the linearity of the instrument. The filter(s) shall.... Filters with exposed filtering media should be checked for opacity every six months; all other filters...

40 CFR 92.122 - Smoke meter calibration.

Code of Federal Regulations, 2012 CFR

2012-07-01

... collection equipment response of zero; (b) Calibrated neutral density filters having approximately 10, 20, and 40 percent opacity shall be employed to check the linearity of the instrument. The filter(s) shall.... Filters with exposed filtering media should be checked for opacity every six months; all other filters...

40 CFR 92.122 - Smoke meter calibration.

Code of Federal Regulations, 2011 CFR

2011-07-01

... collection equipment response of zero; (b) Calibrated neutral density filters having approximately 10, 20, and 40 percent opacity shall be employed to check the linearity of the instrument. The filter(s) shall.... Filters with exposed filtering media should be checked for opacity every six months; all other filters...

40 CFR 86.884-11 - Instrument checks.

Code of Federal Regulations, 2011 CFR

2011-07-01

... collection equipment response of zero; (3) Calibrated neutral density filters having approximately 10, 20, and 40 percent opacity shall be employed to check the linearity of the instrument. The filter(s) shall.... Filters with exposed filtering media should be checked for opacity every six months; all other filters...

40 CFR 86.884-11 - Instrument checks.

Code of Federal Regulations, 2013 CFR

2013-07-01

... collection equipment response of zero; (3) Calibrated neutral density filters having approximately 10, 20, and 40 percent opacity shall be employed to check the linearity of the instrument. The filter(s) shall.... Filters with exposed filtering media should be checked for opacity every six months; all other filters...

40 CFR 60.52Da - Recordkeeping requirements.

Code of Federal Regulations, 2011 CFR

2011-07-01

... (CONTINUED) STANDARDS OF PERFORMANCE FOR NEW STATIONARY SOURCES Standards of Performance for Electric Utility... opacity field data sheets; (2) For each performance test conducted using Method 22 of appendix A-4 of this... performance test; (iii) Copies of all visible emission observer opacity field data sheets; and (iv...

Integrating Subject Pathfinders into Online Catalogs.

ERIC Educational Resources Information Center

Jarvis, William E.

1985-01-01

Discusses the integration of subject pathfinders into online public access catalogs (OPAC) through following features: within the OPAC, offline user guide manuals, remotely printed upon user request, or online as saved searches displayed in help screen format. Excerpts of a pathfinder display for biotechnology are presented. Four sources are…

40 CFR 63.7131 - What reports must I submit and when?

Code of Federal Regulations, 2010 CFR

2010-07-01

... were no deviations from any emission limitations (emission limit, operating limit, opacity limit, and... deviations from the emission limitations during the reporting period. (6) If there were no periods during.... (d) For each deviation from an emission limitation (emission limit, operating limit, opacity limit...

40 CFR 63.1455 - What reports must I submit and when?

Code of Federal Regulations, 2010 CFR

2010-07-01

... from any emission limitations (emission limit, operating limit, opacity limit) that applies to you and... that there were no deviations from the emission limitations, work practice standards, or operation and... deviation from an emission limitation (emission limit, operating limit, opacity limit) and for each...

Gas and dust in the star-forming region ρ Oph A. The dust opacity exponent β and the gas-to-dust mass ratio g2d

NASA Astrophysics Data System (ADS)

Liseau, R.; Larsson, B.; Lunttila, T.; Olberg, M.; Rydbeck, G.; Bergman, P.; Justtanont, K.; Olofsson, G.; de Vries, B. L.

2015-06-01

Aims: We aim at determining the spatial distribution of the gas and dust in star-forming regions and address their relative abundances in quantitative terms. We also examine the dust opacity exponent β for spatial and/or temporal variations. Methods: Using mapping observations of the very dense ρ Oph A core, we examined standard 1D and non-standard 3D methods to analyse data of far-infrared and submillimetre (submm) continuum radiation. The resulting dust surface density distribution can be compared to that of the gas. The latter was derived from the analysis of accompanying molecular line emission, observed with Herschel from space and with APEX from the ground. As a gas tracer we used N2H+, which is believed to be much less sensitive to freeze-out than CO and its isotopologues. Radiative transfer modelling of the N2H+ (J = 3-2) and (J = 6-5) lines with their hyperfine structure explicitly taken into account provides solutions for the spatial distribution of the column density N(H2), hence the surface density distribution of the gas. Results: The gas-to-dust mass ratio is varying across the map, with very low values in the central regions around the core SM 1. The global average, = 88, is not far from the canonical value of 100, however. In ρ Oph A, the exponent β of the power-law description for the dust opacity exhibits a clear dependence on time, with high values of 2 for the envelope-dominated emission in starless Class -1 sources to low values close to 0 for the disk-dominated emission in Class III objects. β assumes intermediate values for evolutionary classes in between. Conclusions: Since β is primarily controlled by grain size, grain growth mostly occurs in circumstellar disks. The spatial segregation of gas and dust, seen in projection toward the core centre, probably implies that, like C18O, also N2H+ is frozen onto the grains. Based on observations with APEX, which is a 12 m diameter submillimetre telescope at 5100 m altitude on Llano Chajnantor in Chile. The telescope is operated by Onsala Space Observatory, Max-Planck-Institut für Radioastronomie (MPIfR), and European Southern Observatory (ESO).And also based on observations with Herschel which is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.FITS files containing the data of Figs. 2, 11, 12, and 16-18 are available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/578/A131

Cataract formation associated with ocular toxocariasis.

PubMed

Ahn, Seong Joon; Woo, Se Joon; Hyon, Joon Young; Park, Kyu Hyung

2013-06-01

To report the clinical features of cataracts in eyes with ocular toxocariasis. Department of Ophthalmology, Seoul National University Bundang Hosptal, Seongnam, South Korea. Retrospective observational case series. The clinical diagnosis of ocular toxocariasis was based on the following characteristic features: retinal granuloma with or without ocular inflammation and positive results in serum antibody enzyme-linked immunosorbent assay. Patients younger than 60 years who presented with a unilateral cataract and were diagnosed with ocular toxocariasis between January 2009 and January 2012 were included. Demographic and ocular examination data for all patients showing atypical cataract features were collected. All cataracts were documented with anterior segment photography. Seven of 83 patients (8.4%) presented with an atypical cataract in the eye with ocular toxocariasis only. The mean patient age was 49.7 years ± 8.3 (SD) (range 38 to 59 years). All patients had small, round, white lens opacities resembling retinal granulomas. The granuloma-like opacities were located primarily in the lens midperiphery and in the subcapsular level. The lens opacity migrated in 1 patient. Ocular toxocariasis can cause a cataract with distinctive clinical features. These cataracts show a granuloma-like opacity primarily in the posterior subcapsular level; the opacity can migrate. No author has a financial or proprietary interest in any material or method mentioned. Copyright © 2013 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

Opportunities for Laboratory Opacity Chemistry Studies to Facilitate Characterization of Young Giant Planets and Brown Dwarfs

NASA Technical Reports Server (NTRS)

Marley, Mark; Freedman, Richard S.

2015-01-01

The thermal emission spectra of young giant planets is shaped by the opacity of atoms and molecules residing in their atmospheres. While great strides have been made in improving the opacities of important molecules, particularly NH3 and CH4, at high temperatures, much more work is needed to understand the opacity and chemistry of atomic Na and K. The highly pressure broadened fundamental band of Na and K in the optical stretches into the near-infrared, strongly influencing the shape of the Y and K spectral bands. Since young giant planets are bright in these bands it is important to understand the influences on the spectral shape. Discerning gravity and atmospheric composition is difficult, if not impossible, without both good atomic opacities as well as an excellent understanding of the relevant atmospheric chemistry. Since Na and K condense at temperatures near 500 to 600 K, the chemistry of the condensation process must be well understood as well, particularly any disequilibrium chemical pathways. Comparisons of the current generation of sophisticated atmospheric models and available data, however, reveal important shortcomings in the models. We will review the current state of observations and theory of young giant planets and will discuss these and other specific examples where improved laboratory measurements for alkali compounds have the potential of substantially improving our understanding of these atmospheres.

Comparison of enamel defects in the primary and permanent dentitions of children from a low-fluoride District in Australia.

PubMed

Seow, W Kim; Ford, Daniel; Kazoullis, Stauros; Newman, Bruce; Holcombe, Trevor

2011-01-01

The purpose of this study was to compare developmental defects of enamel (DDE) in the primary and permanent dentitions of children from a low-fluoride district. A total of 517 healthy schoolchildren were examined using the modified DDE criteria. The prevalence of DDE in the primary and permanent dentition was 25% and 58%, respectively (P<.001). The mean number of teeth with enamel opacity per subject was approximately threefold compared to that affected by enamel hypoplasia (3.1±3.8 vs 0.8±1.4, P<.001 in the primary dentition and 3.6±4.7 vs 1.2±2.2, P<.001 in the permanent dentition). Demarcated opacities (83%) were predominant compared to diffuse opacities (17%), while missing enamel was the most common type of enamel hypoplasia (50%), followed by grooves (31%) and enamel pits (19%) (P=.04). In the permanent dentition, diffuse and demarcated opacities were equally frequent, while enamel grooves were the commonest type of hypoplasia (52%), followed by missing enamel (35%) and enamel pits (5%; P<.001). In a low-fluoride community, developmental defects of enamel were twice as common in the permanent dentition vs the primary dentition. In the primary dentition, the predominant defects were demarcated opacities and missing enamel, while in the permanent dentition, the defects were more variable.

[Bronchiolitis obliterans organizing pneumonia--experience of a pulmonology ward].

PubMed

Fonseca, Ana L; Meruje, Manuela; Barata, Fernando; Martins, Yvette

2007-01-01

Bronchiolitis obliterans organizing pneumonia (BOOP) is a physiopathologic syndrome associating suggestive clinical and imaging features with histopathologic studies showing buds of connective tissue in the lu- men of the distal pulmonary airspace. The aim of the study is a retrospective review of all patients with BOOP diagnosed in the Pulmonology Unit of Coimbra Hospital Centre (CHC) between 2000 and 2005. Eleven cases (6 female and 5 male) with mean age 54.8 years were diagnosed. Ten patients were non-smokers and one was an ex-smoker. The mean duration of symptoms was 62.1 days with the initial symptoms dyspnea (8), cough (7), fever (5) and weight loss (2). Nine patients had been given multiple antibiotics, crackles were heard in 6, fever was detected in 6 and dyspnea in 5. Chest X-ray showed bilateral alveolar opacities in 6, focal consolidation in 3, multiple bilateral nodular opacities in 1 and linear opacities in 1. Lung function, performed in 7 patients, showed a reduction in the diffusion capacity in 5. BAL was performed in 8, and all revealed an increase in the percentage of lymphocytes, with low CD4/CD8 in 4. Diagnosis was obtained by pulmonary biopsy performed by TBLB (7), VATS (2) and TTLB (1). Systemic corticosteroids were given in 9 patients. Evolution was favourable in 10 and one patient died. The authors emphasise the time symptoms took to develop, the failure of multiple antibiotics, agreement between symptoms and imaging with those published in the literature, the increased lymphocytes in the BAL, the usefulness of TBLB and the good response to corticosteroids.

Preliminary results of aerosols' optical properties studied with EPF measurements from the SPICAM/UV instrument

NASA Astrophysics Data System (ADS)

Willame, Y.; Vandaele, A.-C.; Depiesse, C.; Gillotay, D.; Kochenova, S.; Montmessin, F.

2011-10-01

Aerosols on Mars have an important impact on the radiative transfer properties of its atmosphere. Today their spectral properties and therefore their interaction with UV radiation are only poorly known. Improving the radiative transfer modeling requires a better knowledge of their characteristics, in particular of their phase function, single scattering albedo and opacity. We will show that such information can be accessed by using EPF observations.

EMISSIONS OF SULFUR TRIOXIDE FROM COAL-FIRED POWER PLANTS

EPA Science Inventory

Emissions of sulfur trioxide (SO3) are a key component of plume opacity and acid deposition. Consequently, these emissions need to be low enough not to cause opacity violations and acid deposition. Generally, a small fraction of sulfur in coal is converted to SO3 in coal-fired co...

Design Considerations for an OPAC Workstation: An Introduction to Specifications and a Model Configuration.

ERIC Educational Resources Information Center

Martin, Ron G.

1989-01-01

Describes guidelines for an online public access catalog (OPAC) workstation that will support the terminal, printer, and other peripherals. Workstation dimensions, lighting, wire management, printer and paper, acoustical treatment, seating, storage for books and coats, wastebasket, and interior decoration are addressed. Flexibility and simplicity…

40 CFR 75.14 - Specific provisions for monitoring opacity.

Code of Federal Regulations, 2010 CFR

2010-07-01

... PROGRAMS (CONTINUED) CONTINUOUS EMISSION MONITORING Monitoring Provisions § 75.14 Specific provisions for monitoring opacity. (a) Coal-fired units and oil-fired units. The owner or operator shall meet the general... 40 Protection of Environment 16 2010-07-01 2010-07-01 false Specific provisions for monitoring...

40 CFR 75.14 - Specific provisions for monitoring opacity.

Code of Federal Regulations, 2014 CFR

2014-07-01

... PROGRAMS (CONTINUED) CONTINUOUS EMISSION MONITORING Monitoring Provisions § 75.14 Specific provisions for monitoring opacity. (a) Coal-fired units and oil-fired units. The owner or operator shall meet the general... 40 Protection of Environment 17 2014-07-01 2014-07-01 false Specific provisions for monitoring...

40 CFR 75.14 - Specific provisions for monitoring opacity.

Code of Federal Regulations, 2011 CFR

2011-07-01

... PROGRAMS (CONTINUED) CONTINUOUS EMISSION MONITORING Monitoring Provisions § 75.14 Specific provisions for monitoring opacity. (a) Coal-fired units and oil-fired units. The owner or operator shall meet the general... 40 Protection of Environment 16 2011-07-01 2011-07-01 false Specific provisions for monitoring...

40 CFR 75.14 - Specific provisions for monitoring opacity.

Code of Federal Regulations, 2012 CFR

2012-07-01

... PROGRAMS (CONTINUED) CONTINUOUS EMISSION MONITORING Monitoring Provisions § 75.14 Specific provisions for monitoring opacity. (a) Coal-fired units and oil-fired units. The owner or operator shall meet the general... 40 Protection of Environment 17 2012-07-01 2012-07-01 false Specific provisions for monitoring...

40 CFR 75.14 - Specific provisions for monitoring opacity.

Code of Federal Regulations, 2013 CFR

2013-07-01

... PROGRAMS (CONTINUED) CONTINUOUS EMISSION MONITORING Monitoring Provisions § 75.14 Specific provisions for monitoring opacity. (a) Coal-fired units and oil-fired units. The owner or operator shall meet the general... 40 Protection of Environment 17 2013-07-01 2013-07-01 false Specific provisions for monitoring...

40 CFR 75.20 - Initial certification and recertification procedures.

Code of Federal Regulations, 2010 CFR

2010-07-01

... §§ 75.11 through 75.18, where no continuous emission or opacity monitoring system was previously... section. Notwithstanding this paragraph, no continuous emission or opacity monitor systems for a... for loss of initial certification in paragraph (a)(5) of this section for each continuous emission or...

40 CFR 75.20 - Initial certification and recertification procedures.

Code of Federal Regulations, 2012 CFR

2012-07-01

... §§ 75.11 through 75.18, where no continuous emission or opacity monitoring system was previously... section. Notwithstanding this paragraph, no continuous emission or opacity monitor systems for a... for loss of initial certification in paragraph (a)(5) of this section for each continuous emission or...

75 FR 10174 - Source-Specific Federal Implementation Plan for Navajo Generating Station; Navajo Nation

Federal Register 2010, 2011, 2012, 2013, 2014

2010-03-05

... Reclamation, the Los Angeles Department of Water and Power, the Arizona Public Service, the Nevada Power... over any normal 6 minute period, excluding condensed water vapour, and 40% opacity, averaged over 6 minutes, during absorber upset transition periods. The final opacity standard excludes uncombined water...

Solar neutrinos and the influences of opacity, thermal instability, additional neutrino sources, and a central black hole on solar models

NASA Technical Reports Server (NTRS)

Stothers, R. B.; Ezer, D.

1972-01-01

Significant quantities that affect the internal structure of the sun are examined for factors that reduce the temperature near the sun's center. The four factors discussed are: opacity, central black hole, thermal instability, and additional neutrino sources.

40 CFR 60.11 - Compliance with standards and maintenance requirements.

Code of Federal Regulations, 2010 CFR

2010-07-01

... (meaning those fugitive-type emission sources subject only to an opacity standard). (c) The opacity standards set forth in this part shall apply at all times except during periods of startup, shutdown... startup, shutdown, and malfunction, owners and operators shall, to the extent practicable, maintain and...

75 FR 8292 - Approval and Promulgation of Air Quality Implementation Plans; Virginia; Opacity Source...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-02-24

... ENVIRONMENTAL PROTECTION AGENCY 40 CFR Part 52 [EPA-R03-OAR-2010-0009; FRL-9115-8] Approval and Promulgation of Air Quality Implementation Plans; Virginia; Opacity Source Surveillance Methods AGENCY: Environmental Protection Agency (EPA). ACTION: Proposed rule. SUMMARY: EPA proposes to approve the State...

40 CFR Table 1 to Subpart Fffff of... - Emission and Opacity Limits

Code of Federal Regulations, 2011 CFR

2011-07-01

... (CONTINUED) National Emission Standards for Hazardous Air Pollutants for Integrated Iron and Steel... opening in the building or structure housing the discharge end that exhibit opacity greater than 20... the atmosphere any secondary emissions that exit any opening in the building or structure housing the...

40 CFR Table 1 to Subpart Fffff of... - Emission and Opacity Limits

Code of Federal Regulations, 2012 CFR

2012-07-01

... (CONTINUED) National Emission Standards for Hazardous Air Pollutants for Integrated Iron and Steel... opening in the building or structure housing the discharge end that exhibit opacity greater than 20... the atmosphere any secondary emissions that exit any opening in the building or structure housing the...

40 CFR Table 1 to Subpart Fffff of... - Emission and Opacity Limits

Code of Federal Regulations, 2010 CFR

2010-07-01

... (CONTINUED) National Emission Standards for Hazardous Air Pollutants for Integrated Iron and Steel... opening in the building or structure housing the discharge end that exhibit opacity greater than 20... the atmosphere any secondary emissions that exit any opening in the building or structure housing the...

40 CFR Table 1 to Subpart Fffff of... - Emission and Opacity Limits

Code of Federal Regulations, 2013 CFR

2013-07-01

... (CONTINUED) National Emission Standards for Hazardous Air Pollutants for Integrated Iron and Steel... opening in the building or structure housing the discharge end that exhibit opacity greater than 20... the atmosphere any secondary emissions that exit any opening in the building or structure housing the...

40 CFR Table 1 to Subpart Fffff of... - Emission and Opacity Limits

Code of Federal Regulations, 2014 CFR

2014-07-01

... (CONTINUED) National Emission Standards for Hazardous Air Pollutants for Integrated Iron and Steel... opening in the building or structure housing the discharge end that exhibit opacity greater than 20... the atmosphere any secondary emissions that exit any opening in the building or structure housing the...

40 CFR 62.15220 - What additional requirements must I meet for the operation of my continuous emission monitoring...

Code of Federal Regulations, 2011 CFR

2011-07-01

... meet for the operation of my continuous emission monitoring systems and continuous opacity monitoring system? 62.15220 Section 62.15220 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED... the operation of my continuous emission monitoring systems and continuous opacity monitoring system...

40 CFR 62.15220 - What additional requirements must I meet for the operation of my continuous emission monitoring...

Code of Federal Regulations, 2010 CFR

2010-07-01

... meet for the operation of my continuous emission monitoring systems and continuous opacity monitoring system? 62.15220 Section 62.15220 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED... the operation of my continuous emission monitoring systems and continuous opacity monitoring system...

Multimedia Visualizer: An Animated, Object-Based OPAC.

ERIC Educational Resources Information Center

Lee, Newton S.

1991-01-01

Describes the Multimedia Visualizer, an online public access catalog (OPAC) that uses animated visualizations to make it more user friendly. Pictures of the system are shown that illustrate the interactive objects that patrons can access, including card catalog drawers, librarian desks, and bookshelves; and access to multimedia items is described.…

On the relationship between the greenhouse effect, atmospheric photochemistry, and species distribution

NASA Technical Reports Server (NTRS)

Callis, L. B.; Boughner, R. E.; Natarajan, M.

1983-01-01

The coupling that exists between infrared opacity changes and tropospheric (and to a lesser extent stratospheric) chemistry is explored in considerable detail, and the effects arising from various perturbations are examined. The studies are carried out with a fully coupled one-dimensional radiative-convective-photochemical model (RCP) that extends from the surface to 53.5 km and has the capability of calculating surface temperature changes due to both chemical and radiative perturbations. The model encompasses contemporary atmospheric chemistry and photochemistry involving the O(x), HO(x), NO(x), and Cl(x) species.

More missing stellar opacity?

NASA Technical Reports Server (NTRS)

Stothers, Richard B.; Chin, Chao-Wen

1994-01-01

Observational data for Population I stars have shown that blue loops on the Hertzsprung-Russell (H-R) diagram form for stellar masses as low as approximately 4 solar mass. However, current state-of-the-art stellar models, unlike the older ones that were based on smaller opacities, fail to loop out of the red-giant region during core helium burning for masses less than 7 solar mass. A possible explanation is that the currently used Livermore opacities need to be further increased, by at least 70%, at temperatures characteristic of the base of the outer convection zone, around 1 x 10(exp 6) K. Indeed, no other suggested remedy seems to yield a blue loop at the lowest observed loop luminosities.

The influence of H2O line blanketing on the spectra of cool dwarf stars

NASA Technical Reports Server (NTRS)

Allard, F.; Hauschildt, P. H.; Miller, S.; Tennyson, J.

1994-01-01

We present our initial results of model atmosphere calculations for cool M dwarfs using an opacity sampling method and a new list of H2O lines. We obtain significantly improved fits to the infrared spectrum of the M dwarf VB10 when compared to earlier models. H2O is by far the dominant opacity source in cool stars. To illustrate this, we show the Rosseland mean of the total extinction under various assumptions. Our calculations demonstrate the importance of a good treatment of the water opacities in cool stars and the improvements possible by using up-to-date data for the water line absorption.

The lens and cataracts.

PubMed

Matthews, Andrew G

2004-08-01

It is conservatively estimated that some form of lens opacity is present in 5% to 7% of horses with otherwise clinically normal eyes.These opacities can range from small epicapsular remnants of the fetal vasculature to dense and extensive cataract. A cataract is defined technically as any opacity or alteration in the optical homogeneity of the lens involving one or more of the following: anterior epithelium, capsule, cortex, or nucleus. In the horse, cataracts rarely involve the entire lens structure (ie, complete cataracts) and are more usually localized to one anatomic landmark or sector of the lens. Complete cataracts are invariably associated with overt and significant visual disability. Focal or incomplete cataracts alone seldom cause any apparent visual dysfunction in affected horses,however.

Thoracic computerized tomographic (CT) findings in 2009 influenza A (H1N1) virus infection in Isfahan, Iran

PubMed Central

Rostami, Mojtaba; Javadi, Abbas-Ali; Khorvash, Farzin; Mostafavizadeh, Kamyar; Adibi, Atoosa; Babak, Anahita; Ataei, Behrooz; Meidani, Mohsen; Naeini, Alireza Emami; Salehi, Hasan; Avijgan, Majid; Yazdani, Mohammad Reza; Rezaei, Farshid

2011-01-01

BACKGROUND: Pandemic 2009 H1N1 influenza A virus arrived at Isfahan in August 2009. The virus is still circulating in the world. The abnormal thoracic computerized tomographic (CT) scan findings vary widely among the studies of 2009 H1N1 influenza. We evaluated the thoracic CT findings in patients with 2009 H1N1 virus infection to describe findings compared to previously reported findings, and to suggest patterns that may be suggestive for 2009 influenza A (H1N1) in an appropriate clinical setting. METHODS: Retrospectively, the archive of all patients with a diagnosis of 2009 H1N1 influenza A were reviewed, in Al-Zahra Hospital in Isfahan, central Iran, between September 23rd 2009 to February 20th 2010. Out of 216 patients with confirmed 2009 influenza A (H1N1) virus, 26 cases with abnormal CT were enrolled in the study. Radiologic findings were characterized by the type and pattern of opacities and zonal distribution. RESULTS: Patchy infiltration (34.6%), lobar consolidation (30.8%), and interstitial infiltration (26.9%) with airbronchogram (38.5%) were the predominant findings in our patients. Bilateral distribution was seen in 80.8% of the patients. Only one patient (3.8%) showed ground-glass opacity, predominant radiographic finding in the previous reports and severe acute respiratory syndrome (SARS). CONCLUSIONS: The most common thoracic CT findings in pandemic H1N1 were patchy infiltration, lobar consolidation, and interstitial infiltration with airbronchogram and bilateral distribution. While these findings can be associated with other infections; they may be suggestive to 2009 influenza A (H1N1) in the appropriate clinical setting. Various radiographic patterns can be seen in thoracic CT scans of the influenza patients. Imaging findings are nonspecific. PMID:22091280

On the Possibility of Enrichment and Differentiation in Gas Giants During Birth by Disk Instability

NASA Astrophysics Data System (ADS)

Boley, Aaron C.; Durisen, Richard H.

2010-11-01

We investigate the coupling between rock-size solids and gas during the formation of gas giant planets by disk fragmentation in the outer regions of massive disks. In this study, we use three-dimensional radiative hydrodynamic simulations and model solids as a spatial distribution of particles. We assume that half of the total solid fraction is in small grains and half in large solids. The former are perfectly entrained with the gas and set the opacity in the disk, while the latter are allowed to respond to gas drag forces, with the back reaction on the gas taken into account. To explore the maximum effects of gas-solid interactions, we first consider 10 cm size particles. We then compare these results to a simulation with 1 km size particles, which explores the low-drag regime. We show that (1) disk instability planets have the potential to form large cores due to aerodynamic capturing of rock-size solids in spiral arms before fragmentation; (2) temporary clumps can concentrate tens of M ⊕ of solids in very localized regions before clump disruption; (3) the formation of permanent clumps, even in the outer disk, is dependent on the grain-size distribution, i.e., the opacity; (4) nonaxisymmetric structure in the disk can create disk regions that have a solids-to-gas ratio greater than unity; (5) the solid distribution may affect the fragmentation process; (6) proto-gas giants and proto-brown dwarfs can start as differentiated objects prior to the H2 collapse phase; (7) spiral arms in a gravitationally unstable disk are able to stop the inward drift of rock-size solids, even redistributing them to larger radii; and (8) large solids can form spiral arms that are offset from the gaseous spiral arms. We conclude that planet embryo formation can be strongly affected by the growth of solids during the earliest stages of disk accretion.

40 CFR 60.2870 - What are the recordkeeping and reporting requirements for air curtain incinerators?

Code of Federal Regulations, 2011 CFR

2011-07-01

... SOURCES Emissions Guidelines and Compliance Times for Commercial and Industrial Solid Waste Incineration... records of results of all initial and annual opacity tests onsite in either paper copy or electronic... annual opacity test reports as electronic or paper copy on or before the applicable submittal date and...

40 CFR 60.2870 - What are the recordkeeping and reporting requirements for air curtain incinerators?

Code of Federal Regulations, 2010 CFR

2010-07-01

... SOURCES Emissions Guidelines and Compliance Times for Commercial and Industrial Solid Waste Incineration... records of results of all initial and annual opacity tests onsite in either paper copy or electronic... annual opacity test reports as electronic or paper copy on or before the applicable submittal date and...

Observations of Reflectivity of the Martian Surface in the Mars Orbiter Laser Altimeter (MOLA) Investigation

NASA Technical Reports Server (NTRS)

Ivanov, Anton B.; Muhleman, Duane O.

2000-01-01

We are presenting results of calculation of the surface albedo of Mars at 1 micron wavelength from the Mars Orbiter Laser Altimeter (MOLA) reflectivity measurements. The Mars Global Surveyor Thermal Emission Spectrometer (MGS TES) 9 micron opacity is employed to remove opacity from the MOLA measurements.

77 FR 2466 - Approval, Disapproval and Promulgation of Air Quality Implementation Plans; Colorado: Smoke...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-01-18

..., Disapproval and Promulgation of Air Quality Implementation Plans; Colorado: Smoke, Opacity and Sulfur Dioxide... Carbon Monoxide, NO 2 mean Nitrogen Dioxide and SO 2 mean Sulfur Dioxide. The initials BACT mean Best.... Summary of SIP Revisions Colorado's Regulation 1 governs opacity, particulates, sulfur dioxide (SO 2...

Engineering analysis of lightweight high-opacity newsprint production by fiber loading

Treesearch

John H. Klungness; Matthew L. Stroika; Marguerite S. Sykes; Said M. Abubakr; Werner Witek; Oliver U. Heise

1999-01-01

We estimated the capital effectiveness of fiber loading in regard to producing lightweight high-opacity newsprint. Fiber loading enhances fiber bonding at increased precipitated calcium carbonate levels without significant loss in Canadian standard freeness or additional use of energy. We investigated the return on investment (ROI) for fiber loading precipitated...

Reduction of greenhouse gases by fiber-loaded lightweight, high-opacity newsprint production

Treesearch

John H. Klungness; Matthew L. Stroika; Said M. Abubakr

1999-01-01

We estimated the effectiveness of fiber loading in reducing greenhouse gas emissions for producing lightweight high-opacity newsprint. Fiber loading enhances fiber bonding at increased precipitated calcium carbonate levels without significant loss in Canadian Standard Freeness or additional energy use. We investigated the reduction of greenhouse gas emissions for a...

76 FR 49391 - Approval, Disapproval and Promulgation of Air Quality Implementation Plans; Colorado; Smoke...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-08-10

..., Disapproval and Promulgation of Air Quality Implementation Plans; Colorado; Smoke, Opacity and Sulfur Dioxide... opacity, particulate, sulfur dioxide (SO 2 ), and carbon monoxide (CO) emissions from sources. EPA has... mean Nitrogen Dioxide and SO2 mean Sulfur Dioxide. (vii) The initials BACT mean Best Available Control...

"Garbage" In, "Refuse and Refuse Disposal" Out: Making the Most of the Subject Authority File in OPAC.

ERIC Educational Resources Information Center

Horn, Marguerite E.

2002-01-01

Discusses the difference in subject access in OPACs (online public access catalogs) between subject searching (authority, alphabetic, or controlled vocabulary) versus keyword searching (uncontrolled, free text, natural language vocabulary). Compares a query on the term "garbage" in two online catalogs and discusses results. (Author/LRW)

Designing the OPAC User Interface to Improve Access and Retrieval.

ERIC Educational Resources Information Center

Basista, Thomas; And Others

1991-01-01

Discussion of problems with retrieval of records in library online public access catalogs (OPACs) focuses on an ongoing research project at the Indiana University of Pennsylvania (IUP) that has been trying to improve subject retrieval vocabulary control using natural and thesaural language and on the design of a good graphical user interface.…

40 CFR 62.15215 - What is required for my continuous opacity monitoring system and how are the data used?

Code of Federal Regulations, 2010 CFR

2010-07-01

... initial evaluation of your continuous opacity monitoring system according to Performance Specification 1 in appendix B of 40 CFR part 60. Complete this evaluation by 180 days after your final compliance... ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) APPROVAL AND PROMULGATION OF STATE PLANS...

40 CFR 60.1760 - What is required for my continuous opacity monitoring system and how are the data used?

Code of Federal Regulations, 2010 CFR

2010-07-01

... ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) STANDARDS OF PERFORMANCE FOR NEW STATIONARY... monitoring system according to § 60.13. (c) Complete an initial evaluation of your continuous opacity monitoring system according to Performance Specification 1 in appendix B of this part. Complete the...

40 CFR 60.1765 - What additional requirements must I meet for the operation of my continuous emission monitoring...

Code of Federal Regulations, 2011 CFR

2011-07-01

... meet for the operation of my continuous emission monitoring systems and continuous opacity monitoring system? 60.1765 Section 60.1765 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... continuous emission monitoring systems and continuous opacity monitoring system? Use the required span values...

40 CFR 60.1275 - What additional requirements must I meet for the operation of my continuous emission monitoring...

Code of Federal Regulations, 2010 CFR

2010-07-01

... meet for the operation of my continuous emission monitoring systems and continuous opacity monitoring... additional requirements must I meet for the operation of my continuous emission monitoring systems and continuous opacity monitoring system? Use the required span values and applicable performance specifications...

40 CFR 60.1275 - What additional requirements must I meet for the operation of my continuous emission monitoring...

Code of Federal Regulations, 2011 CFR

2011-07-01

... meet for the operation of my continuous emission monitoring systems and continuous opacity monitoring... additional requirements must I meet for the operation of my continuous emission monitoring systems and continuous opacity monitoring system? Use the required span values and applicable performance specifications...

40 CFR 60.1765 - What additional requirements must I meet for the operation of my continuous emission monitoring...

Code of Federal Regulations, 2010 CFR

2010-07-01

... meet for the operation of my continuous emission monitoring systems and continuous opacity monitoring system? 60.1765 Section 60.1765 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... continuous emission monitoring systems and continuous opacity monitoring system? Use the required span values...

Target simulations with SCROLL non-LTE opacity/emissivity databases.

NASA Astrophysics Data System (ADS)

Klapisch, M.; Colombant, D.; Bar-Shalom, A.

2001-10-01

SCROLL[1], a collisional radiative model and code based on superconfigurations, is able to compute high Z non-LTE opacities and emissivities accurately and efficiently. It was used to create opacity/emissivity databases for Pd, Lu, Au on a 50 temperatures/80 densities grid. Incident radiation field was shown to have no effect on opacities in the case of interest, and was not taken into account. These databases were introduced in the hydrocode FAST1D[2]. SCROLL also gives an ionization temperature Tz which is used in FAST1D to obtain non-LTE corrections to the equation of state. Results will be compared to those of a previous version using Busquet’s algorithm[3]. Work supported by USDOE under a contract with NRL. [1] A. Bar-Shalom, J. Oreg and M. Klapisch, J. Quant. Spectrosc. Radiat. Transfer, 65, 43(2000). [2] J. H. Gardner, A. J. Schmitt, J. P. Dahlburg, C. J. Pawley, S. E. Bodner, S. P. Obenschain, V. Serlin and Y. Aglitskiy, Phys. Plasmas, 5, 1935 (1998). [3] M. Busquet, Phys. Fluids B, 5, 4191 (1993).

OPAC (orange peel activated carbon) derived from waste orange peel for the adsorption of chlorophenoxyacetic acid herbicides from water: Adsorption isotherm, kinetic modelling and thermodynamic studies.

PubMed

Pandiarajan, Aarthi; Kamaraj, Ramakrishnan; Vasudevan, Sudharshan; Vasudevan, Subramanyan

2018-08-01

This study presents the orange peel activated carbon (OPAC), derived from biowaste precursor (orange peel) by single step pyrolysis method and its application for the adsorption of chlorophenoxyacetic acid herbicides from the water. The OPAC exhibited the surface area of 592.471 m 2  g -1 , pore volume and pore diameter of 0.242 cc g -1 and 1.301 nm respectively. The adsorption kinetics and thermodynamic equilibrium modelling for all chlorophenoxyacetic acid herbicides were investigated. The various parametric effects such as pH and temperature were evaluated. A pseudo-second-order kinetic model was well fitted for all the herbicides. The Langmuir isotherm was obeyed for all the herbicides and the maximum Langmuir capacity of 574.71 mg g -1 was achieved. The thermodynamic studies revealed that the adsorption increases with increase in temperature. The results shows that the orange peel derived carbon (OPAC) as effective and efficient adsorbent material for the removal of chlorophenoxyacid herbicides from the water. Copyright © 2018 Elsevier Ltd. All rights reserved.

EBL Inhomogeneity and Hard-Spectrum Gamma-Ray Sources

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abdalla, Hassan; Böttcher, Markus

2017-02-01

The unexpectedly hard very-high-energy (VHE; E > 100 GeV) γ -ray spectra of a few distant blazars have been interpreted as evidence of a reduction of the γγ opacity of the universe due to the interaction of VHE γ -rays with the extragalactic background light (EBL) compared to the expectation from current knowledge of the density and cosmological evolution of the EBL. One of the suggested solutions to this problem involves the inhomogeneity of the EBL. In this paper, we study the effects of such inhomogeneity on the energy density of the EBL (which then also becomes anisotropic) and themore » resulting γγ opacity. Specifically, we investigate the effects of cosmic voids along the line of sight to a distant blazar. We find that the effect of such voids on the γγ opacity, for any realistic void size, is only of the order of ≲1% and much smaller than expected from a simple linear scaling of the γγ opacity with the line-of-sight galaxy underdensity due to a cosmic void.« less

Effect of liquid crystal birefringence on the opacity and off-axis haze of PDLC films

NASA Astrophysics Data System (ADS)

Pane, S.; Caporusso, M.

1998-02-01

PDLC systems are thin films consisting of a dispersion of liquid crystal micro-droplets in a continuous solid phase of polymer matrix. Application of an electric field on a thin layer of PDLC sandwiched between two transparent on-state. This effect make them useful for a wide variety of applications. Among them, smart windows for architectural is the most popular subject in literature. For this application, the key parameters of performance are the haze and the opacity. There are essentially two technologies used to prepare PDLC films, namely micro-encapsulation and phase separation.In the present work we will show the correlation between the opacity and the off-axis haze in PDLC films prepared with a phase separation technology. We will give the general rule in order to select the liquid crystal properties that allow the preparation of high opacity ad low haze PDLC films. Further study about the control of the parameters which influence the performances of PDLC films prepared with phase separation technology and the difference with the NCAP approach are in progress at our laboratory.

Optical properties of polypropylene upon recycling.

PubMed

De Santis, Felice; Pantani, Roberto

2013-01-01

In the last few years there has been an increasing interest in the possibility of recycling polymeric materials, using physical recycling. However, is it well known that polymers experience a depletion of all the properties upon recycling. These effects have been widely characterized in the literature for what concerns the mechanical or rheological properties. The changes of optical properties after recycling have been much less studied, even if, especially in food packaging, optical characteristics (above all the opacity) are of extreme importance, and thus it is quite significant to assess the effect of recycling on these properties. In this work, the influence of recycling steps on the opacity of films of a commercial grade of isotactic polypropylene (i-PP) was studied. The material was extruded several times to mimic the effect of recycling procedures. After extrusion, films were obtained by cooling samples of material at different cooling rates. The opacity of the obtained films was then measured and related to their crystallinity and morphology. It was found that opacity generally increases on increasing the amount of α phase and for the same amount of α phase on increasing the size of the spherulites.

Diagnosis of high-temperature implosions using low- and high-opacity Krypton lines

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yaakobi, B.; Epstein, R.; Hooper, C.F. Jr.

1996-04-01

High-temperature laser target implosions can be achieved by using relatively thin-shell targets, and they can be. diagnosed by doping the fuel with krypton and measuring K-shell and L-shell lines. Electron temperatures of up to 5 keV at modest compressed densities ({approximately}1-5g/cm{sup 3}) are predicted for such experiments, with ion temperatures peaking above 10 keV at the center. It is found that the profiles of low-opacity (optically thin) lines in the expected density range are dominated by the Doppler broadening and can provide a measurement of the ion temperature if spectrometers of spectral resolution {Delta}{lambda}/{lambda} {ge} 1000 are used. For high-opacitymore » lines, obtained with a higher krypton fill pressure, the measurement of the escape factor can yield the {rho}R of the compressed fuel. At higher densities, Stark broadening of low-opacity lines becomes important and can provide a density measurement, whereas lines of higher opacity can be used to estimate the extent of mixing.« less

Vitrectomy for primary symptomatic vitreous opacities: an evidence-based review

PubMed Central

Ivanova, T; Jalil, A; Antoniou, Y; Bishop, P N; Vallejo-Garcia, J L; Patton, N

2016-01-01

Floaters are a common ocular condition which form as a consequence of aging changes in the vitreous. Although in most patients the symptoms are minimal, they can cause significant impairment in vision-related quality of life in a small population of patients. Recently there has been an increase in awareness of the visual disability caused by floaters, and the evidence-base for treatment of this condition using small-gauge vitrectomy has increased. In this review, we define the term ‘floaters' as symptomatic vitreous opacities (SVO). We suggest a classification dependent on the presence or absence of posterior vitreous detachment and discuss their pathogenesis and natural history. We review their impact on patients' quality of life related to visual function. We review the psychological factors that may have a role in some patients who appear to be affected by SVO to the extent that they pursue all options including surgery with all its attendant risks. We summarise the available evidence-base of treatment options available for SVO with special emphasis on the safety and efficacy of vitrectomy for this condition. PMID:26939559

FIRST NEW SOLAR MODELS WITH OPAS OPACITY TABLES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Le Pennec, M.; Turck-Chièze, S.; Salmon, S.

Stellar seismology appears more and more as a powerful tool for a better determination of the fundamental properties of solar-type stars. However, the particular case of the Sun is still challenging. For about a decade now, the helioseismic sound-speed determination has continued to disagree with the standard solar model (SSM) prediction, questioning the reliability of this model. One of the sources of uncertainty could be in the treatment of the transport of radiation from the solar core to the surface. In this Letter, we use the new OPAS opacity tables, recently available for solar modeling, to address this issue. Wemore » discuss first the peculiarities of these tables, then we quantify their impact on the solar sound-speed and density profiles using the reduced OPAS tables taken on the grids of the OPAL ones. We use the two evolution codes, Modules for Experiments in Stellar Astrophysics and Code Liégeois d’Evolution Stellaire, that led to similar conclusions in the solar radiative zone. In comparison to commonly used OPAL opacity tables, the new solar models are computed for the most recent photospheric composition with OPAS tables and present improvements to the location of the base of the convective zone and to the description of the solar radiative zone in comparison to the helioseismic observations, even if the differences in the Rosseland mean opacity do not exceed 6%. We finally carry out a comparison to a solar model computed with the OP opacity tables.« less

[The occupational radiation-induced cataract in five industrial radiographers].

PubMed

Benzarti Mezni, A; Loukil, I; Hriz, N; Kallel, K; Mlaiki, N; Ben Jemaâ, A

2012-04-01

The industrial uses of ionizing radiation in Tunisia are expanding, especially in industry and most particularly in the nondestructive testing of welds. Thus workers operating in the non-destructive testing of welds may develop a radiation-induced cataract varying in time to onset depending on the dose. To describe the characteristics of the radiation-induced cataract in patients exposed to ionizing radiation, determine the risk factors of radiation-induced cataracts. This was an anamnestic, clinical, and environmental study of five cases of radiation-induced cataract in workers employed in non-destructive testing of welds. This series of five cases had a mean age of 30.2 years and 5.53 years of work experience, ranging from 14 months to 15 years. All the patients were male and industrial radiographers specialized in nondestructive testing of welds. The average duration of exposure to ionizing radiation was 5.53 years. None of the patients had worn protective gear such as eye goggles. The ophthalmic check-up for the five special industrial radiographers showed punctuate opacities in three cases, punctiform opacities in one eye in one case, and phacosclerosis with bilateral lens multiple crystalline stromal opacities in a case of micro-lens opacities in both eyes with opalescence of both eyes in one case. These cataracts had been declared as occupational diseases. The value of a specialized ophthalmologic surveillance among these workers and the early diagnosis of lens opacities must be emphasized. Copyright © 2011 Elsevier Masson SAS. All rights reserved.

The role of atmospheric heat transport in the seasonal carbon dioxide cycle

NASA Technical Reports Server (NTRS)

Pollack, James B.; Haberle, R. M.; Murphy, James R.; Schaeffer, J.

1993-01-01

We have carried out numerical experiments with a general circulations model (GCM) and energy balance model of the martian atmosphere to define the importance of heat transported to the polar regions in determining the amount of CO2 condensed on the surface during the fall and winter seasons and the amount sublimated during the spring and summer seasons. In so doing, we performed both sensitivity experiments, in which the dust opacity was varied over the full range of its observed values, and annual simulations, in which the dust opacity varied continuously with seasonal data, in accord with measurements taken at the Viking landers. Dust opacity represents the key variable for determining the contribution of atmospheric heat advection to the energy budget in the polar regions. The amount of heat advected to the winter polar regions increases monotonically as the dust opacity at low and middle latitudes increases. However, the increase is sharpest between optical depths of 0 and 1 tends to level off at still higher optical depths. Heat advection is more important at times of CO2 condensation than CO2 sublimation, since the temperature gradients are much steeper in the winter hemisphere than in the summer hemisphere. Because dust opacity is much higher during northern winter than during southern winter, atmospheric heat advection reduces the amount of CO2 that condenses in the north by a much larger factor than it does in the south.

The reflectivity of Mars at 1064 nm: Derivation from Mars Orbiter Laser Altimeter data and application to climatology and meteorology

NASA Astrophysics Data System (ADS)

Heavens, N. G.

2017-06-01

The Mars Orbiter Laser Altimeter (MOLA) on board Mars Global Surveyor (MGS) made > 108 measurements of the reflectivity of Mars at 1064 nm (R1064) by both active sounding and passive radiometry. Past studies of R1064 neglected the effects of atmospheric opacity and viewing geometry on both active and passive measurements and also identified a potential calibration issue with passive radiometry. Therefore, as yet, there exists no acceptable reference R1064 to derive a column opacity product for atmospheric studies and planning future orbital lidar observations. Here, such a reference R1064 is derived by seeking R1064M,N: a Minnaert-corrected normal albedo under clear conditions and assuming minimal phase angle dependence. Over darker surfaces, R1064M,N and the absolute level of atmospheric opacity were estimated from active sounding. Over all surfaces, the opacity derived from active sounding was used to exclude passive radiometry measurements made under opaque conditions and estimate R1064M,N. These latter estimates then were re-calibrated by comparison with RM,N derived from Hubble Space Telescope (HST) observations over areas of approximately uniform reflectivity. Estimates of R1064M,N from re-calibrated passive radiometry typically agree with HST observations within 10%. The resulting R1064M,N is then used to derive and quantify the uncertainties of a column opacity product, which can be applied to meteorological and climatological studies of Mars, particularly to detect and measure mesoscale cloud/aerosol structures.

Conceptual design of initial opacity experiments on the national ignition facility

NASA Astrophysics Data System (ADS)

Heeter, R. F.; Bailey, J. E.; Craxton, R. S.; Devolder, B. G.; Dodd, E. S.; Garcia, E. M.; Huffman, E. J.; Iglesias, C. A.; King, J. A.; Kline, J. L.; Liedahl, D. A.; McKenty, P. W.; Opachich, Y. P.; Rochau, G. A.; Ross, P. W.; Schneider, M. B.; Sherrill, M. E.; Wilson, B. G.; Zhang, R.; Perry, T. S.

2017-02-01

Accurate models of X-ray absorption and re-emission in partly stripped ions are necessary to calculate the structure of stars, the performance of hohlraums for inertial confinement fusion and many other systems in high-energy-density plasma physics. Despite theoretical progress, a persistent discrepancy exists with recent experiments at the Sandia Z facility studying iron in conditions characteristic of the solar radiative-convective transition region. The increased iron opacity measured at Z could help resolve a longstanding issue with the standard solar model, but requires a radical departure for opacity theory. To replicate the Z measurements, an opacity experiment has been designed for the National Facility (NIF). The design uses established techniques scaled to NIF. A laser-heated hohlraum will produce X-ray-heated uniform iron plasmas in local thermodynamic equilibrium (LTE) at temperatures eV and electron densities 21~\\text{cm}-3$ . The iron will be probed using continuum X-rays emitted in a ps, diameter source from a 2 mm diameter polystyrene (CH) capsule implosion. In this design, of the NIF beams deliver 500 kJ to the mm diameter hohlraum, and the remaining directly drive the CH capsule with 200 kJ. Calculations indicate this capsule backlighter should outshine the iron sample, delivering a point-projection transmission opacity measurement to a time-integrated X-ray spectrometer viewing down the hohlraum axis. Preliminary experiments to develop the backlighter and hohlraum are underway, informing simulated measurements to guide the final design.

Galactic cold cores. V. Dust opacity

NASA Astrophysics Data System (ADS)

Juvela, M.; Ristorcelli, I.; Marshall, D. J.; Montillaud, J.; Pelkonen, V.-M.; Ysard, N.; McGehee, P.; Paladini, R.; Pagani, L.; Malinen, J.; Rivera-Ingraham, A.; Lefèvre, C.; Tóth, L. V.; Montier, L. A.; Bernard, J.-P.; Martin, P.

2015-12-01

Context. The project Galactic Cold Cores has carried out Herschel photometric observations of interstellar clouds where the Planck satellite survey has located cold and compact clumps. The sources represent different stages of cloud evolution from starless clumps to protostellar cores and are located in different Galactic environments. Aims: We examine this sample of 116 Herschel fields to estimate the submillimetre dust opacity and to search for variations that might be attributed to the evolutionary stage of the sources or to environmental factors, including the location within the Galaxy. Methods: The submillimetre dust opacity was derived from Herschel data, and near-infrared observations of the reddening of background stars are converted into near-infrared optical depth. We investigated the systematic errors affecting these parameters and used modelling to correct for the expected biases. The ratio of 250 μm and J band opacities is correlated with the Galactic location and the star formation activity. We searched for local variations in the ratio τ(250 μm)/τ(J) using the correlation plots and opacity ratio maps. Results: We find a median ratio of τ(250 μm) /τ(J) = (1.6 ± 0.2) × 10-3, which is more than three times the mean value reported for the diffuse medium. Assuming an opacity spectral index β = 1.8 instead of β = 2.0, the value would be lower by ~ 30%. No significant systematic variation is detected with Galactocentric distance or with Galactic height. Examination of the τ(250 μm) /τ(J) maps reveals six fields with clear indications of a local increase of submillimetre opacity of up to τ(250 μm) /τ(J) ~ 4 × 10-3 towards the densest clumps. These are all nearby fields with spatially resolved clumps of high column density. Conclusions: We interpret the increase in the far-infrared opacity as a sign of grain growth in the densest and coldest regions of interstellar clouds. Planck (http://www.esa.int/Planck) is a project of the European Space Agency - ESA - with instruments provided by two scientific consortia funded by ESA member states (in particular the lead countries: France and Italy) with contributions from NASA (USA), and telescope reflectors provided in a collaboration between ESA and a scientific Consortium led and funded by Denmark.Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.Tables 1 and E.1 are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/584/A93Appendices are available in electronic form at http://www.aanda.org

Effect of quantifying peptide release on ruminal protein degradation determined using the inhibitor in vitro system.

PubMed

Colombini, S; Broderick, G A; Clayton, M K

2011-04-01

The aim of this work was to compare use of an o-phthaldialdehyde (OPA) colorimetric assay (OPA-C), which responds to both free AA and peptides, with an OPA fluorimetric assay (OPA-F), which is insensitive to peptides, to quantify rates of ruminal protein degradation in the inhibitor in vitro system using Michaelis-Menten saturation kinetics. Four protein concentrates (expeller-extracted soybean meal, ESBM; 2 solvent-extracted soybean meals, SSBM1 and SSBM2; and casein) were incubated in a ruminal in vitro system treated with hydrazine and chloramphenicol to inhibit microbial uptake of protein degradation products. Proteins were weighed to give a range of N concentrations (from 0.15 to 3 mg of N/mL of inoculum) and incubated with 10 mL of ruminal inoculum and 5 mL of buffer; fermentations were stopped after 2 h by adding trichloroacetic acid (TCA). Proteins were analyzed for buffer-soluble N and buffer extracts were treated with TCA to determine N degraded at t=0 (FD0). The TCA supernatants were analyzed for ammonia (phenol-hypochlorite assay), total AA (TAA; OPA-F), and TAA plus oligopeptides (OPA-C) by flow injection analysis. Velocity of protein degradation was computed from extent of release of 1) ammonia plus free TAA or 2) ammonia plus free TAA and peptides. Rate of degradation (kd) was quantified using nonlinear regression of the integrated Michaelis-Menten equation. The parameters Km (Michaelis constant) and kd (Vmax/Km), where Vmax=maximum velocity, were estimated directly; kd values were adjusted (Akd) for the fraction FD0 using the equation Akd=kd-FD0/2. The OPA-C assay yielded faster degradation rates due to the contribution of peptides to the fraction degraded (overall mean=0.280/h by OPA-C and 0.219/h by OPA-F). Degradation rates for SSBM samples (0.231/h and 0.181/h) and ESBM (0.086/h) obtained by the OPA-C assay were more rapid than rates reported by the National Research Council (NRC). Both assays indicated that the 2 SSBM differed in rumen-undegradable protein (RUP) content; the more slowly degraded SSBM had RUP content (35% by OPA-C) similar to that reported by the NRC. The RUP content of ESBM (42% by OPA-C) was lower than the NRC value. Preliminary studies with 4 additional protein concentrates confirmed that accounting for peptide formation increased degradation rate; however, a trend for an interaction between assay and protein source suggested that peptide release made a smaller contribution to rate for more slowly degraded proteins. The OPA-C assay is a simple and reliable method to quantify formation of small peptides. Copyright © 2011 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Semin Chong; Kyung Soo Lee; Myung Jin Chung

Pneumoconiosis may be classified as either fibrotic or nonfibrotic, according to the presence or absence of fibrosis. Silicosis, coal worker pneumoconiosis, asbestosis, berylliosis, and talcosis are examples of fibrotic pneumoconiosis. Siderosis, stannosis, and baritosis are nonfibrotic forms of pneumoconiosis that result from inhalation of iron oxide, tin oxide, and barium sulfate particles, respectively. In an individual who has a history of exposure to silica or coal dust, a finding of nodular or reticulonodular lesions at chest radiography or small nodules with a perilymphatic distribution at thin-section computed tomography (CT), with or without eggshell calcifications, is suggestive of silicosis or coalmore » worker pneumoconiosis. Magnetic resonance imaging is helpful for distinguishing between progressive massive fibrosis and lung cancer. CT and histopathologic findings in asbestosis are similar to those in idiopathic pulmonary fibrosis, but the presence of asbestos bodies in histopathologic specimens is specific for the diagnosis of asbestosis. Giant cell interstitial pneumonia due to exposure to hard metals is classified as a fibrotic form of pneumoconiosis and appears on CT images as mixed ground-glass opacities and reticulation. Berylliosis simulates pulmonary sarcoidosis on CT images. CT findings in talcosis include small centrilobular and subpleural nodules or heterogeneous conglomerate masses that contain foci of high attenuation indicating talc deposition. Siderosis is nonfibrotic and is indicated by a CT finding of poorly defined centrilobular nodules or ground-glass opacities.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Saumon, D.; Holberg, J. B.; Kowalski, P. M., E-mail: dsaumon@lanl.gov, E-mail: holberg@argus.lpl.arizona.edu, E-mail: p.kowalski@fz-juelich.de

The atmospheres of very cool, hydrogen-rich white dwarfs (WDs) (T{sub eff} < 6000 K) are challenging to model because of the increased complexity of the equation of state, chemical equilibrium, and opacity sources in a low-temperature, weakly ionized dense gas. In particular, many models that assume relatively simple models for the broadening of atomic levels and mostly ideal gas physics overestimate the flux in the blue part of their spectra. A solution to this problem that has met with some success is that additional opacity at short wavelengths comes for the extreme broadening of the Lyman α line of atomicmore » H by collisions primarily with H{sub 2}. For the purpose of validating this model more rigorously, we acquired Hubble Space Telescope STIS spectra of eight very cool WDs (five DA and three DC stars). Combined with their known parallaxes, BVRIJHK, and Spitzer IRAC photometry, we analyze their entire spectral energy distribution (from 0.24 to 9.3 μm) with a large grid of model atmospheres and synthetic spectra. We find that the red wing of the Lyman α line reproduces the rapidly decreasing near-UV flux of these very cool stars very well. We determine better constrained values of T{sub eff} and gravity as well as upper limits to the helium abundance in their atmospheres.« less

Experimental study on particulate and NOx emissions of a diesel engine fueled with ultra low sulfur diesel, RME-diesel blends and PME-diesel blends.

PubMed

Zhu, Lei; Zhang, Wugao; Liu, Wei; Huang, Zhen

2010-02-01

Ultra low sulfur diesel and two different kinds of biodiesel fuels blended with baseline diesel fuel in 5% and 20% v/v were tested in a Cummins 4BTA direct injection diesel engine, with a turbocharger and an intercooler. Experiments were conducted under five engine loads at two steady speeds (1500 rpm and 2500 rpm). The study aims at investigating the engine performance, NO(x) emission, smoke opacity, PM composition, PM size distribution and comparing the impacts of low sulfur content of biodiesel with ULSD on the particulate emission. The results indicate that, compared to base diesel fuel, the increase of biodiesel in blends could cause certain increase in both brake specific fuel consumption and brake thermal efficiency. Compared with baseline diesel fuel, the biodiesel blends bring about more NO(x) emissions. With the proportion of biodiesel increase in blends, the smoke opacity decreases, while total particle number concentration increases. Meanwhile the ULSD gives lower NO(x) emissions, smoke opacity and total number concentration than those of baseline diesel fuel. In addition, the percentages of SOF and sulfate in particulates increase with biodiesel in blends, while the dry soot friction decreases obviously. Compared with baseline diesel fuel, the biodiesel blends increase the total nucleation number concentration, while ULSD reduces the total nucleation number concentration effectively, although they all have lower sulfur content. It means that, for ULSD, the lower sulfur content is the dominant factor for suppressing nucleation particles formation, while for biodiesel blends, lower volatile, lower aromatic content and higher oxygen content of biodiesel are key factors for improving the nucleation particles formation. The results demonstrate that the higher NO(x) emission and total nucleation number concentration are considered as the big obstacles of the application of biodiesel in diesel engine. Copyright 2009 Elsevier B.V. All rights reserved.

INFRARED TRANSMISSION SPECTROSCOPY OF THE EXOPLANETS HD 209458b AND XO-1b USING THE WIDE FIELD CAMERA-3 ON THE HUBBLE SPACE TELESCOPE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Deming, Drake; Wilkins, Ashlee; McCullough, Peter

Exoplanetary transmission spectroscopy in the near-infrared using the Hubble Space Telescope (HST) NICMOS is currently ambiguous because different observational groups claim different results from the same data, depending on their analysis methodologies. Spatial scanning with HST/WFC3 provides an opportunity to resolve this ambiguity. We here report WFC3 spectroscopy of the giant planets HD 209458b and XO-1b in transit, using spatial scanning mode for maximum photon-collecting efficiency. We introduce an analysis technique that derives the exoplanetary transmission spectrum without the necessity of explicitly decorrelating instrumental effects, and achieves nearly photon-limited precision even at the high flux levels collected in spatial scanmore » mode. Our errors are within 6% (XO-1) and 26% (HD 209458b) of the photon-limit at a resolving power of {lambda}/{delta}{lambda} {approx} 70, and are better than 0.01% per spectral channel. Both planets exhibit water absorption of approximately 200 ppm at the water peak near 1.38 {mu}m. Our result for XO-1b contradicts the much larger absorption derived from NICMOS spectroscopy. The weak water absorption we measure for HD 209458b is reminiscent of the weakness of sodium absorption in the first transmission spectroscopy of an exoplanet atmosphere by Charbonneau et al. Model atmospheres having uniformly distributed extra opacity of 0.012 cm{sup 2} g{sup -1} account approximately for both our water measurement and the sodium absorption. Our results for HD 209458b support the picture advocated by Pont et al. in which weak molecular absorptions are superposed on a transmission spectrum that is dominated by continuous opacity due to haze and/or dust. However, the extra opacity needed for HD 209458b is grayer than for HD 189733b, with a weaker Rayleigh component.« less

Infrared Transmission Spectroscopy of the Exoplanets HD 209458b and XO-1b Using the Wide Field Camera-3 on the Hubble Space Telescope

NASA Astrophysics Data System (ADS)

Deming, Drake; Wilkins, Ashlee; McCullough, Peter; Burrows, Adam; Fortney, Jonathan J.; Agol, Eric; Dobbs-Dixon, Ian; Madhusudhan, Nikku; Crouzet, Nicolas; Desert, Jean-Michel; Gilliland, Ronald L.; Haynes, Korey; Knutson, Heather A.; Line, Michael; Magic, Zazralt; Mandell, Avi M.; Ranjan, Sukrit; Charbonneau, David; Clampin, Mark; Seager, Sara; Showman, Adam P.

2013-09-01

Exoplanetary transmission spectroscopy in the near-infrared using the Hubble Space Telescope (HST) NICMOS is currently ambiguous because different observational groups claim different results from the same data, depending on their analysis methodologies. Spatial scanning with HST/WFC3 provides an opportunity to resolve this ambiguity. We here report WFC3 spectroscopy of the giant planets HD 209458b and XO-1b in transit, using spatial scanning mode for maximum photon-collecting efficiency. We introduce an analysis technique that derives the exoplanetary transmission spectrum without the necessity of explicitly decorrelating instrumental effects, and achieves nearly photon-limited precision even at the high flux levels collected in spatial scan mode. Our errors are within 6% (XO-1) and 26% (HD 209458b) of the photon-limit at a resolving power of λ/δλ ~ 70, and are better than 0.01% per spectral channel. Both planets exhibit water absorption of approximately 200 ppm at the water peak near 1.38 μm. Our result for XO-1b contradicts the much larger absorption derived from NICMOS spectroscopy. The weak water absorption we measure for HD 209458b is reminiscent of the weakness of sodium absorption in the first transmission spectroscopy of an exoplanet atmosphere by Charbonneau et al. Model atmospheres having uniformly distributed extra opacity of 0.012 cm2 g-1 account approximately for both our water measurement and the sodium absorption. Our results for HD 209458b support the picture advocated by Pont et al. in which weak molecular absorptions are superposed on a transmission spectrum that is dominated by continuous opacity due to haze and/or dust. However, the extra opacity needed for HD 209458b is grayer than for HD 189733b, with a weaker Rayleigh component.

Herschel and SCUBA-2 observations of dust emission in a sample of Planck cold clumps

NASA Astrophysics Data System (ADS)

Juvela, Mika; He, Jinhua; Pattle, Katherine; Liu, Tie; Bendo, George; Eden, David J.; Fehér, Orsolya; Michel, Fich; Fuller, Gary; Hirano, Naomi; Kim, Kee-Tae; Li, Di; Liu, Sheng-Yuan; Malinen, Johanna; Marshall, Douglas J.; Paradis, Deborah; Parsons, Harriet; Pelkonen, Veli-Matti; Rawlings, Mark G.; Ristorcelli, Isabelle; Samal, Manash R.; Tatematsu, Ken'ichi; Thompson, Mark; Traficante, Alessio; Wang, Ke; Ward-Thompson, Derek; Wu, Yuefang; Yi, Hee-Weon; Yoo, Hyunju

2018-04-01

Context. Analysis of all-sky Planck submillimetre observations and the IRAS 100 μm data has led to the detection of a population of Galactic cold clumps. The clumps can be used to study star formation and dust properties in a wide range of Galactic environments. Aims: Our aim is to measure dust spectral energy distribution (SED) variations as a function of the spatial scale and the wavelength. Methods: We examined the SEDs at large scales using IRAS, Planck, and Herschel data. At smaller scales, we compared JCMT/SCUBA-2 850 μm maps with Herschel data that were filtered using the SCUBA-2 pipeline. Clumps were extracted using the Fellwalker method, and their spectra were modelled as modified blackbody functions. Results: According to IRAS and Planck data, most fields have dust colour temperatures TC 14-18 K and opacity spectral index values of β = 1.5-1.9. The clumps and cores identified in SCUBA-2 maps have T 13 K and similar β values. There are some indications of the dust emission spectrum becoming flatter at wavelengths longer than 500 μm. In fits involving Planck data, the significance is limited by the uncertainty of the corrections for CO line contamination. The fits to the SPIRE data give a median β value that is slightly above 1.8. In the joint SPIRE and SCUBA-2 850 μm fits, the value decreases to β 1.6. Most of the observed T-β anticorrelation can be explained by noise. Conclusions: The typical submillimetre opacity spectral index β of cold clumps is found to be 1.7. This is above the values of diffuse clouds, but lower than in some previous studies of dense clumps. There is only tentative evidence of a T-β anticorrelation and β decreasing at millimetre wavelengths. Planck (http://www.esa.int/Planck) is a project of the European Space Agency - ESA - with instruments provided by two scientific consortia funded by ESA member states (in particular the lead countries: France and Italy) with contributions from NASA (USA), and telescope reflectors provided in a collaboration between ESA and a scientific consortium led and funded by Denmark.Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.

Galactic cold cores. VI. Dust opacity spectral index

NASA Astrophysics Data System (ADS)

Juvela, M.; Demyk, K.; Doi, Y.; Hughes, A.; Lefèvre, C.; Marshall, D. J.; Meny, C.; Montillaud, J.; Pagani, L.; Paradis, D.; Ristorcelli, I.; Malinen, J.; Montier, L. A.; Paladini, R.; Pelkonen, V.-M.; Rivera-Ingraham, A.

2015-12-01

Context. The Galactic Cold Cores project has carried out Herschel photometric observations of 116 fields where the Planck survey has found signs of cold dust emission. The fields contain sources in different environments and different phases of star formation. Previous studies have revealed variations in their dust submillimetre opacity. Aims: The aim is to measure the value of dust opacity spectral index and to understand its variations spatially and with respect to other parameters, such as temperature, column density, and Galactic location. Methods: The dust opacity spectral index β and the dust colour temperature T are derived using Herschel and Planck data. The relation between β and T is examined for the whole sample and inside individual fields. Results: Based on IRAS and Planck data, the fields are characterised by a median colour temperature of 16.1 K and a median opacity spectral index of β = 1.84. The values are not correlated with Galactic longitude. We observe a clear T-β anti-correlation. In Herschel observations, constrained at lower resolution by Planck data, the variations follow the column density structure and βFIR can rise to ~2.2 in individual clumps. The highest values are found in starless clumps. The Planck 217 GHz band shows a systematic excess that is not restricted to cold clumps and is thus consistent with a general flattening of the dust emission spectrum at millimetre wavelengths. When fitted separately below and above 700 μm, the median spectral index values are βFIR ~ 1.91 and β(mm) ~ 1.66. Conclusions: The spectral index changes as a function of column density and wavelength. The comparison of different data sets and the examination of possible error sources show that our results are robust. However, β variations are partly masked by temperature gradients and the changes in the intrinsic grain properties may be even greater. Planck http://www.esa.int/Planck is a project of the European Space Agency - ESA - with instruments provided by two scientific consortia funded by ESA member states (in particular the lead countries: France and Italy) with contributions from NASA (USA), and telescope reflectors provided in a collaboration between ESA and a scientific consortium led and funded by Denmark.Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.Table 3 is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/584/A94Appendices are available in electronic form at http://www.aanda.org

Impact of Internet Search Engines on OPAC Users: A Study of Punjabi University, Patiala (India)

ERIC Educational Resources Information Center

Kumar, Shiv

2012-01-01

Purpose: The aim of this paper is to study the impact of internet search engine usage with special reference to OPAC searches in the Punjabi University Library, Patiala, Punjab (India). Design/methodology/approach: The primary data were collected from 352 users comprising faculty, research scholars and postgraduate students of the university. A…

40 CFR 60.2865 - How must I monitor opacity for air curtain incinerators?

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 6 2010-07-01 2010-07-01 false How must I monitor opacity for air curtain incinerators? 60.2865 Section 60.2865 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) STANDARDS OF PERFORMANCE FOR NEW STATIONARY SOURCES Emissions Guidelines and Compliance Times for Commercial and...

40 CFR 60.2865 - How must I monitor opacity for air curtain incinerators?

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 6 2011-07-01 2011-07-01 false How must I monitor opacity for air curtain incinerators? 60.2865 Section 60.2865 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) STANDARDS OF PERFORMANCE FOR NEW STATIONARY SOURCES Emissions Guidelines and Compliance Times for Commercial and...

40 CFR 60.2255 - How must I monitor opacity for air curtain incinerators?

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 6 2011-07-01 2011-07-01 false How must I monitor opacity for air curtain incinerators? 60.2255 Section 60.2255 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) STANDARDS OF PERFORMANCE FOR NEW STATIONARY SOURCES Standards of Performance for Commercial and Industrial Solid...

40 CFR 60.2255 - How must I monitor opacity for air curtain incinerators?

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 6 2010-07-01 2010-07-01 false How must I monitor opacity for air curtain incinerators? 60.2255 Section 60.2255 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) STANDARDS OF PERFORMANCE FOR NEW STATIONARY SOURCES Standards of Performance for Commercial and Industrial Solid...

40 CFR 63.1505 - Emission standards for affected sources and emission units.

Code of Federal Regulations, 2010 CFR

2010-07-01

...-on air pollution control device if a continuous opacity monitor (COM) or visible emissions monitoring... percent opacity from any PM add-on air pollution control device if a COM is chosen as the monitoring.../delacquering kiln/decoating kiln is equipped with an afterburner having a design residence time of at least 1...

40 CFR 63.1505 - Emission standards for affected sources and emission units.

Code of Federal Regulations, 2014 CFR

2014-07-01

... any PM add-on air pollution control device if a continuous opacity monitor (COM) or visible emissions... percent opacity from any PM add-on air pollution control device if a COM is chosen as the monitoring.../delacquering kiln/decoating kiln is equipped with an afterburner having a design residence time of at least 1...

Delivering Electronic Resources with Web OPACs and Other Web-based Tools: Needs of Reference Librarians.

ERIC Educational Resources Information Center

Bordeianu, Sever; Carter, Christina E.; Dennis, Nancy K.

2000-01-01

Describes Web-based online public access catalogs (Web OPACs) and other Web-based tools as gateway methods for providing access to library collections. Addresses solutions for overcoming barriers to information, such as through the implementation of proxy servers and other authentication tools for remote users. (Contains 18 references.)…

40 CFR 60.293 - Standards for particulate matter from glass melting furnace with modified-processes.

Code of Federal Regulations, 2014 CFR

2014-07-01

... container glass, flat glass, and pressed and blown glass with a soda-lime recipe melting furnaces. (2..., maintain, and operate a continuous monitoring system for the measurement of the opacity of emissions... conducted by § 60.8, conduct continuous opacity monitoring during each test run. (3) Calculate 6-minute...

40 CFR 60.293 - Standards for particulate matter from glass melting furnace with modified-processes.

Code of Federal Regulations, 2013 CFR

2013-07-01

... container glass, flat glass, and pressed and blown glass with a soda-lime recipe melting furnaces. (2..., maintain, and operate a continuous monitoring system for the measurement of the opacity of emissions... conducted by § 60.8, conduct continuous opacity monitoring during each test run. (3) Calculate 6-minute...

40 CFR 60.293 - Standards for particulate matter from glass melting furnace with modified-processes.

Code of Federal Regulations, 2010 CFR

2010-07-01

... container glass, flat glass, and pressed and blown glass with a soda-lime recipe melting furnaces. (2..., maintain, and operate a continuous monitoring system for the measurement of the opacity of emissions... conducted by § 60.8, conduct continuous opacity monitoring during each test run. (3) Calculate 6-minute...

40 CFR 60.293 - Standards for particulate matter from glass melting furnace with modified-processes.

Code of Federal Regulations, 2012 CFR

2012-07-01

... container glass, flat glass, and pressed and blown glass with a soda-lime recipe melting furnaces. (2..., maintain, and operate a continuous monitoring system for the measurement of the opacity of emissions... conducted by § 60.8, conduct continuous opacity monitoring during each test run. (3) Calculate 6-minute...

40 CFR 60.293 - Standards for particulate matter from glass melting furnace with modified-processes.

Code of Federal Regulations, 2011 CFR

2011-07-01

... container glass, flat glass, and pressed and blown glass with a soda-lime recipe melting furnaces. (2..., maintain, and operate a continuous monitoring system for the measurement of the opacity of emissions... conducted by § 60.8, conduct continuous opacity monitoring during each test run. (3) Calculate 6-minute...

OPACs in the Clouds

ERIC Educational Resources Information Center

Webb, Paula L.; Nero, Muriel D.

2009-01-01

In today's world of instant everything, everyone has been exposed to some form of Web 2.0 technology, and higher education is not exempt from its long reach. Libraries of all types are incorporating Web 2.0 features to attract users as well as to showcase library services. The Online Public Access Catalog (OPAC) has become more user-friendly with…

EGFR-mutant Non-small Cell Lung Cancer Accompanied by Transient Asymptomatic Pulmonary Opacities Successfully Treated with "Stop-And-Go" Osimertinib.

PubMed

Kobayashi, Keigo; Naoki, Katsuhiko; Kuroda, Aoi; Yasuda, Hiroyuki; Kawada, Ichiro; Soejima, Kenzo; Betsuyaku, Tomoko

2018-04-01

A 69-year-old man with post-operative recurrence of lung adenocarcinoma was treated with multiple chemotherapies, including epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors. A second biopsy revealed an EGFR T790M mutation. As 10th-line chemotherapy, osimertinib was initiated. After 24 weeks, chest computed tomography (CT) revealed asymptomatic ground-glass opacities in both lobes. After four weeks of osimertinib discontinuation, imaging revealed rapid lung cancer progression. Osimertinib was resumed. After 11 weeks, CT revealed decreased lung nodules with no exacerbation of interstitial lung disease. We describe a patient who experienced transient asymptomatic pulmonary opacities during treatment with osimertinib, which was successfully managed by a "stop-and-go" approach.

Observation of a strong inverse temperature dependence for the opacity of atmospheric water vapor in the mm continuum near 280 GHz

NASA Technical Reports Server (NTRS)

Emmons, Louisa K.; De Zafra, Robert L.

1990-01-01

Results are presented of the field measurements of atmospheric opacity at 278 GHz (9.3/cm) conducted at the McMurdo Station (Antarctica) during the austral springs of 1986 and 1987, in conjunction with balloon measurements of water vapor profile and total column density, showing a strong inverse temperature dependence when normalized to precipitable water vapor. The value of measured opacity per mm of precipitable water vapor (PWV) is roughly two times greater at -35 C than at -10 C and three times greater than measurements at +25 C reported by Zammit and Ade (1981). Various theories proposed to explain excess absorption in continuum regions are reviewed.

Development of an Aerosol Opacity Retrieval Algorithm for Use with Multi-Angle Land Surface Images

NASA Technical Reports Server (NTRS)

Diner, D.; Paradise, S.; Martonchik, J.

1994-01-01

In 1998, the Multi-angle Imaging SpectroRadiometer (MISR) will fly aboard the EOS-AM1 spacecraft. MISR will enable unique methods for retrieving the properties of atmospheric aerosols, by providing global imagery of the Earth at nine viewing angles in four visible and near-IR spectral bands. As part of the MISR algorithm development, theoretical methods of analyzing multi-angle, multi-spectral data are being tested using images acquired by the airborne Advanced Solid-State Array Spectroradiometer (ASAS). In this paper we derive a method to be used over land surfaces for retrieving the change in opacity between spectral bands, which can then be used in conjunction with an aerosol model to derive a bound on absolute opacity.

Fly ash system technology improves opacity

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

2007-06-15

Unit 3 of the Dave Johnston Power Plant east of Glenrock, WY, USA had problems staying at or below the opacity limits set by the state. The unit makes use of a Lodge Cottrell precipitator. When the plant changed to burning Power River Basin coal, ash buildup became a significant issue as the fly ash control system was unable to properly evacuate hoppers on the unit. To overcome the problem, the PLC on the unit was replaced with a software optimization package called SmartAsh for the precipitator fly ash control system, at a cost of $500,000. After the upgrade, theremore » have been no plugged hoppers and the opacity has been reduced from around 20% to 3-5%. 2 figs.« less

Interpretation of indeterminate lung scintigrams. [/sup 99m/Tc, /sup 133/Xe

DOE Office of Scientific and Technical Information (OSTI.GOV)

Biello, D.R.; Mattar, A.G.; Osei-Wusu, A.

1979-10-01

Lung scintigrams and pulmonary angiograms of 111 patients with suspected pulmonary embolism who had matching perfusion defects and radiographic abnormalities (infiltrate, atelectasis, or effusion) were reviewed. In 14 patients perfusion defects were substantially smaller than the corresponding radiographic opacity; only 1 (7%) had pulmonary embolism. In 77 the opacities and perfusion defects were of similar size; the abnormality was due to embolism in 20 (26%). In 18 patients perfusion defects were substantially larger than the radiographic opacities and were not associated with matching ventilation abnormalities; of these, 16 (89%) had pulmonary embolism. Evaluation of the relative size of perfusion defectsmore » and radiographic abnormalities occurring in the same region improves the ability of lung scintigrams to predict pulmonary emboli.« less

First Iron Opacity Experiments on the National Ignition Facility

NASA Astrophysics Data System (ADS)

Perry, Theodore; Dodd, Evan; Cardenas, Tana; Devolder, Barbara; Flippo, Kirk; Johns, Heather; Kline, John; Sherrill, Manolo; Urbatsch, Todd; Heeter, Robert; Ahmed, Maryum; Emig, James; Iglesias, Carlos; Liedahl, Duane; London, Richard; Martin, Madison; Schneider, Marilyn; Thompson, Nathaniel; Wilson, Brian; Opachich, Yekaterina; King, James; Huffman, Eric; Knight, Russel; Bailey, James; Rochau, Gregory

2017-10-01

Iron opacity experiments on the Sandia National Laboratories Z machine have shown up to factors of two discrepancies between theory and experiment. To help resolve these discrepancies an experimental platform for doing comparable opacity experiments is being developed on the National Ignition Facility (NIF). Initial iron data has been taken at a temperature of 150 eV and an electron density of 6x1021/cm3, but higher temperatures and densities will be required to address the discrepancies that have been observed in the Z experiments. The plans to go to higher temperatures and densities and how to deal with current issues with instrumental backgrounds will be discussed. Performed under the auspices of USDOE LANL Contract DE-AC52-06NA25396.

Two Cases of Tuberous Sclerosis Complex Suggestive of Complicating Multifocal Micronodular Pneumocyte Hyperplasia: A Case Report.

PubMed

Nishida, Chinatsu; Yatera, Kazuhiro; Kido, Takashi; Noguchi, Shingo; Akata, Kentaro; Hanaka, Minako; Yamasaki, Kei; Hoshino, Teppei; Shimono, Masayuki; Ishimoto, Hiroshi; Sakamoto, Noriho; Mukae, Hiroshi

Multifocal micronodular pneumocyte hyperplasia (MMPH) is pathologically characterized by multifocal nodular hyperplasia of type Ⅱ pneumocyte-like cells. MMPH is usually complicated with tuberous sclerosis complex (TSC). MMPH patients tend to be asymptomatic or only slightly symptomatic. MMPH tends to progress slowly and needs no treatment. We herein describe two cases of MMPH with its characteristic radiological features and clinical manifestations of TSC. Case 1: a 20-year-old female with definitive TSC in infancy. Chest CT at the age of 18 revealed multiple nodular opacities and ground-glass attenuations in a scattered and random distribution in the bilateral lungs. Case 2: a 44-year-old female with probable TSC at 36 years of age. Chest CT at the age of 43 showed random areas of small ground-glass attenuations, predominantly in the upper lung fields. Case 1 and Case 2 have had no respiratory symptoms or radiographic changes in the recent two years and four years, respectively. Although pathological examinations of the lung were not performed because consent for surgical lung biospies was unobtainable, we considered that these pulmonary manifestations were most likely MMPH with TSC because of these characteristic radiographical findings of multiple nodular opacities and ground-glass attenuations of 10 mm or less in size and their scattered distribution, and because there have been no abnormal laboratory data or changes in their chest radiological findings for years. Neither patient is under treatment for pulmonary lesions. Although MMPH is a rare disease, multiple nodules and ground-glass attenuations on lung imaging findings should be considered as pulmonary manifestations in patients with TSC.

ON HIGHLY CLUMPED MAGNETIC WIND MODELS FOR COOL EVOLVED STARS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Harper, G. M.

2010-09-10

Recently, it has been proposed that the winds of non-pulsating and non-dusty K and M giants and supergiants may be driven by some form of magnetic pressure acting on highly clumped wind material. While many researchers believe that magnetic processes are responsible for cool evolved stellar winds, existing MHD and Alfven wave-driven wind models have magnetic fields that are essentially radial and tied to the photosphere. The clumped magnetic wind scenario is quite different in that the magnetic flux is also being carried away from the star with the wind. We test this clumped wind hypothesis by computing continuum radiomore » fluxes from the {zeta} Aur semiempirical model of Baade et al., which is based on wind-scattered line profiles. The radio continuum opacity is proportional to the electron density squared, while the line scattering opacity is proportional to the gas density. This difference in proportionality provides a test for the presence of large clumping factors. We derive the radial distribution of clump factors (CFs) for {zeta} Aur by comparing the nonthermal pressures required to produce the semiempirical velocity distribution with the expected thermal pressures. The CFs are {approx}5 throughout the sub-sonic inner wind region and then decline outward. These implied clumping factors lead to excess radio emission at 2.0 cm, while at 6.2 cm it improves agreement with the smooth unclumped model. Smaller clumping factors of {approx}2 lead to better overall agreement but also increase the discrepancy at 2 cm. These results do not support the magnetic clumped wind hypothesis and instead suggest that inherent uncertainties in the underlying semiempirical model probably dominate uncertainties in predicted radio fluxes. However, new ultraviolet line and radio continuum observations are needed to test the new generations of inhomogeneous magnetohydrodynamic wind models.« less

Cloud Ozone Dust Imager (CODI). Volume 1; Investigation and Technical Plan

NASA Technical Reports Server (NTRS)

Clancy, R. Todd; Dusenbery, Paul; Wolff, Michael; James, Phil; Allen, Mark; Goguen, Jay; Kahn, Ralph; Gladstone, Rany; Murphy, Jim

1995-01-01

The Cloud Ozone Dust Imager (CODI) is proposed to investigate the current climatic balance of the Mars atmosphere, with particular emphasis on the important but poorly understood roles which dust and water ice aerosols play in this balance. The large atmospheric heating (20-50 K) resulting from global dust storms around Mars perihelion is well recognized. However, groundbased observations of Mars atmospheric temperatures, water vapor, and clouds since the Viking missions have identified a much colder, cloudier atmosphere around Mars aphelion that may prove as important as global dust storms in determining the interannual and long-term behavior of the Mars climate. The key climate issues CODI is designed to investigate are: 1) the degree to which non-linear interactions between atmospheric dust heating, water vapor saturation, and cloud nucleation influence the seasonal and interannual variability of the Mars atmosphere, and 2) whether the strong orbital forcing of atmospheric dust loading, temperatures and water vapor saturation determines the long-term balance of Mars water, as reflected in the north-south hemispheric asymmetries of atmospheric water vapor and polar water ice abundances. The CODI experiment will measure the daily, seasonal and (potentially) interannual variability of atmospheric dust and cloud opacities, and the key physical properties of these aerosols which determine their role in the climate cycles of Mars. CODI is a small (1.2 kg), fixed pointing camera, in which four wide-angle (+/- 70 deg) lenses illuminate fixed filters and CCD arrays. Simultaneous sky/surface imaging of Mars is obtained at an angular resolution of 0.28 deg/pixel for wavelengths of 255, 336, 502, and 673 nm (similar to Hubble Space Telescope filters). These wavelengths serve to measure atmospheric ozone (255 and 336 nm), discriminate ice and dust aerosols (336 and 673 nm), and construct color images (336, 502, and 673 nm). The CODI images are detected on four 512 x 512 pixel arrays, as partitioned on two 1024 x 1024 CCD's operated in frame transfer mode. The center of the CODI field-of-view is canted 40 deg from the zenith direction to obtain sky brightness measurements and a 20 deg surface field-of-view. Daily image observations will be conducted when the Sun is greater than or equal to 5 deg outside the edge of the CODI field-of-view, and twilight and nighttime imaging will obtained on a weekly basis. The 673 nm channel includes a polarizer wheel to obtain sky/surface polarimetry. A dust cover protects the entire lens assemblies of all four CODI channels. This opaque dust cover, which is normally opened for CODI imaging, includes a small fixed mirror and transparent window positioned above the 673 nm lens, to redirect the 673 nm field-of-view to the surface for descent imaging. Fixed pointing, internal data buffering, low operating power (2-4 W for less than or equal to 30 seconds), selective data transmission, and simple operational characteristics of the CODI experiment place minimum resource and operational demands on the Mars Surveyor 1998 lander. The CODI science goals are optimized for, but not restricted to, a low-latitude landing site (20 deg S-30 deg N). The primary CODI measurement objectives are the opacities, wave forms, particle properties (size, shape, and alignment), and heights of clouds; the opacities, particle properties, and vertical distribution of dust; and the opacity and vertical distribution of ozone. The variability of cloud, ozone, and dust opacities will be determined on diurnal, daily, and seasonal timescales. Wind velocities will be determined from cloud motions and wave characteristics; and the temporal variability of atmospheric water vapor, with limited altitude information, will be inferred from the CODI ozone observations. Secondary measurement objectives include limited descent imaging capability, surface uv-visible photometry and polarimetry, photochemistry, and meteorite infall rates.

Cloud Ozone Dust Imager (CODI)

NASA Astrophysics Data System (ADS)

Clancy, R. Todd; Dusenbery, Paul; Wolff, Michael; James, Phil; Allen, Mark; Goguen, Jay; Kahn, Ralph; Gladstone, Rany; Murphy, Jim

1995-01-01

The Cloud Ozone Dust Imager (CODI) is proposed to investigate the current climatic balance of the Mars atmosphere, with particular emphasis on the important but poorly understood roles which dust and water ice aerosols play in this balance. The large atmospheric heating (20-50 K) resulting from global dust storms around Mars perihelion is well recognized. However, groundbased observations of Mars atmospheric temperatures, water vapor, and clouds since the Viking missions have identified a much colder, cloudier atmosphere around Mars aphelion that may prove as important as global dust storms in determining the interannual and long-term behavior of the Mars climate. The key climate issues CODI is designed to investigate are: 1) the degree to which non-linear interactions between atmospheric dust heating, water vapor saturation, and cloud nucleation influence the seasonal and interannual variability of the Mars atmosphere, and 2) whether the strong orbital forcing of atmospheric dust loading, temperatures and water vapor saturation determines the long-term balance of Mars water, as reflected in the north-south hemispheric asymmetries of atmospheric water vapor and polar water ice abundances. The CODI experiment will measure the daily, seasonal and (potentially) interannual variability of atmospheric dust and cloud opacities, and the key physical properties of these aerosols which determine their role in the climate cycles of Mars. CODI is a small (1.2 kg), fixed pointing camera, in which four wide-angle (+/- 70 deg) lenses illuminate fixed filters and CCD arrays. Simultaneous sky/surface imaging of Mars is obtained at an angular resolution of 0.28 deg/pixel for wavelengths of 255, 336, 502, and 673 nm (similar to Hubble Space Telescope filters). These wavelengths serve to measure atmospheric ozone (255 and 336 nm), discriminate ice and dust aerosols (336 and 673 nm), and construct color images (336, 502, and 673 nm). The CODI images are detected on four 512 x 512 pixel arrays, as partitioned on two 1024 x 1024 CCD's operated in frame transfer mode. The center of the CODI field-of-view is canted 40 deg from the zenith direction to obtain sky brightness measurements and a 20 deg surface field-of-view. Daily image observations will be conducted when the Sun is greater than or equal to 5 deg outside the edge of the CODI field-of-view, and twilight and nighttime imaging will obtained on a weekly basis. The 673 nm channel includes a polarizer wheel to obtain sky/surface polarimetry. A dust cover protects the entire lens assemblies of all four CODI channels. This opaque dust cover, which is normally opened for CODI imaging, includes a small fixed mirror and transparent window positioned above the 673 nm lens, to redirect the 673 nm field-of-view to the surface for descent imaging. Fixed pointing, internal data buffering, low operating power (2-4 W for less than or equal to 30 seconds), selective data transmission, and simple operational characteristics of the CODI experiment place minimum resource and operational demands on the Mars Surveyor 1998 lander. The CODI science goals are optimized for, but not restricted to, a low-latitude landing site (20 deg S-30 deg N). The primary CODI measurement objectives are the opacities, wave forms, particle properties (size, shape, and alignment), and heights of clouds; the opacities, particle properties, and vertical distribution of dust; and the opacity and vertical distribution of ozone. The variability of cloud, ozone, and dust opacities will be determined on diurnal, daily, and seasonal timescales. Wind velocities will be determined from cloud motions and wave characteristics; and the temporal variability of atmospheric water vapor, with limited altitude information, will be inferred from the CODI ozone observations. Secondary measurement objectives include limited descent imaging capability, surface uv-visible photometry and polarimetry, photochemistry, and meteorite infall rates.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kataria, T.; Showman, A. P.; Fortney, J. J.

We present three-dimensional atmospheric circulation models of GJ 1214b, a 2.7 Earth-radius, 6.5 Earth-mass super Earth detected by the MEarth survey. Here we explore the planet's circulation as a function of atmospheric metallicity and atmospheric composition, modeling atmospheres with a low mean molecular weight (MMW; i.e., H{sub 2}-dominated) and a high MMW (i.e., water- and CO{sub 2}-dominated). We find that atmospheres with a low MMW have strong day-night temperature variations at pressures above the infrared photosphere that lead to equatorial superrotation. For these atmospheres, the enhancement of atmospheric opacities with increasing metallicity lead to shallower atmospheric heating, larger day-night temperaturemore » variations, and hence stronger superrotation. In comparison, atmospheres with a high MMW have larger day-night and equator-to-pole temperature variations than low MMW atmospheres, but differences in opacity structure and energy budget lead to differences in jet structure. The circulation of a water-dominated atmosphere is dominated by equatorial superrotation, while the circulation of a CO{sub 2}-dominated atmosphere is instead dominated by high-latitude jets. By comparing emergent flux spectra and light curves for 50× solar and water-dominated compositions, we show that observations in emission can break the degeneracy in determining the atmospheric composition of GJ 1214b. The variation in opacity with wavelength for the water-dominated atmosphere leads to large phase variations within water bands and small phase variations outside of water bands. The 50× solar atmosphere, however, yields small variations within water bands and large phase variations at other characteristic wavelengths. These observations would be much less sensitive to clouds, condensates, and hazes than transit observations.« less

Enamel defects and dental caries in 9-year-old children living in fluoridated and nonfluoridated areas of Auckland, New Zealand.

PubMed

Kanagaratnam, Sathananthan; Schluter, Philip; Durward, Callum; Mahood, Robyn; Mackay, Tim

2009-06-01

This epidemiological study aims to investigate the developmental enamel defects and dental caries among 9-year-old children resident in fluoridated and nonfluoridated regions in Auckland, New Zealand. A stratified, two-stage random selection design where strata were defined by fluoridation status, school size, and school decile. After informed consent was obtained, parents completed oral health questionnaires and children underwent dental examinations at school clinics. 612 children from 38 schools participated in the study. Overall, 175 (29%) children had lived continuously in fluoridated areas, 149 (24%) had lived continuously in nonfluoridated areas, and 288 (47%) had resided intermittently in fluoridated areas. Diffuse opacities were present in 117 (19%) children and deciduous teeth dental caries was seen in 370 (60%) children. After adjustment for covariates, a strong dose-response relationship between diffuse opacity and fluoridation status was found, with children who lived continuously in fluoridated areas being 4.17 times as likely to have diffuse opacities as children who lived continuously in nonfluoridated areas (P < 0.001). Conversely, a strong protective dose-response relationship between caries experience and fluoridation status was seen, with children who lived continuously in fluoridated areas being 0.42 times as likely to have dental caries as children who lived continuously in nonfluoridated areas (P < 0.001). Reticulated water fluoridation in Auckland reduces the risk of dental caries but increases the risk of diffuse opacities in 9-year-old children. Guidelines and health-promotion strategies that enable children to minimize their risk to diffuse opacities yet reduce their risk of dental caries should be reviewed.

Characteristics of Anterior Lens Opacities in Children

PubMed Central

Dixit, Lena; Puente, Michael; Yen, Kimberly G.

2017-01-01

Background: Anterior lens opacities (ALO) are found in 3-14% of pediatric patients with cataracts. No clear guidelines exist in the management and treatment of these cataracts. Objective: To evaluate pediatric patients with anterior lens opacities and assess rate of amblyopia and need for surgery over time. Methods: A retrospective chart review was performed on patients with unilateral and bilateral anterior lens opacities (ALOs) seen between January 2008 and December 2014. Size, location, and type of ALO were noted. Refractive error, necessity for treatment of amblyopia, and interventions were recorded. Results: A total of 31 patients were included in the study. 17 patients had unilateral ALOs and 14 had bilateral ALOs. The majority of the cataracts (90.3%) were centrally located. The most common type of cataract was the polar type of cataract and the vast majority (48.4%) was < 1mm in size. 38.7% of patients had concurrent ocular conditions and 9.7% had systemic associations. 28.6% of patients with bilateral cataracts and 35.3% of the patients with unilateral cataracts were treated for amblyopia. Three patients required cataract surgery. Conclusion: About half of anterior lens opacities are less than 1mm in size and the majority are of the polar type. Risk of amblyopia in these patients is higher than in the general population. Anisometropia is the most common cause of amblyopia. Ocular associations are seen at a relatively high frequency and systemic associations can occur but are uncommon. The need for surgical intervention is infrequent; however, growth of ALOs and associated cortical changes may be risk factors for surgery. PMID:28553426

Phenotype-genotype correlation in potential female carriers of X-linked developmental cataract (Nance-Horan syndrome).

PubMed

Khan, Arif O; Aldahmesh, Mohammed A; Mohamed, Jawahir Y; Alkuraya, Fowzan S

2012-06-01

To correlate clinical examination with underlying genotype in asymptomatic females who are potential carriers of X-linked developmental cataract (Nance-Horan syndrome). An ophthalmologist blind to the pedigree performed comprehensive ophthalmic examination for 16 available family members (two affected and six asymptomatic females, five affected and three asymptomatic males). Facial features were also noted. Venous blood was collected for sequencing of the gene NHS. All seven affected family members had congenital or infantile cataract and facial dysmorphism (long face, bulbous nose, abnormal dentition). The six asymptomatic females ranged in age from 4-35 years old. Four had posterior Y-suture centered lens opacities; these four also exhibited the facial dysmorphism of the seven affected family members. The fifth asymptomatic girl had scattered fine punctate lens opacities (not centered on the Y-suture) while the sixth had clear lenses, and neither exhibited the facial dysmorphism. A novel NHS mutation (p.Lys744AsnfsX15 [c.2232delG]) was found in the seven patients with congenital or infantile cataract. This mutation was also present in the four asymptomatic girls with Y-centered lens opacities but not in the other two asymptomatic girls or in the three asymptomatic males (who had clear lenses). Lens opacities centered around the posterior Y-suture in the context of certain facial features were sensitive and specific clinical signs of carrier status for NHS mutation in asymptomatic females. Lens opacities that did not have this characteristic morphology in a suspected female carrier were not a carrier sign, even in the context of her affected family members.

Heating rate profiles and radiative forcing due to a dust storm in the Western Mediterranean using satellite observations

NASA Astrophysics Data System (ADS)

Peris-Ferrús, C.; Gómez-Amo, J. L.; Marcos, C.; Freile-Aranda, M. D.; Utrillas, M. P.; Martínez-Lozano, J. A.

2017-07-01

We analyze the vertically-resolved radiative impact due to a dust storm in the Western Mediterranean. The dust plume travels around 3-5 km altitude and the aerosol optical depth derived by MODIS at 550 nm ranges from 0.33 to 0.52 at the overpass time (13:05 UT). The aerosol radiative forcing (ARF), forcing efficiency (FE) and heating rate profile (AHR) are determined throughout the dust trajectory in shortwave (SW) and longwave (LW) ranges. To do this, we integrate different satellite observations (CALIPSO and MODIS) and detailed radiative transfer modeling. The combined (SW + LW) effect of the dust event induces a net cooling in the studied region. On average, the FE at 22.4° solar zenith angle is -190.3 W m-2 and -38.1 W m-2, at surface and TOA, respectively. The corresponding LW/SW offset is 14% and 38% at surface and TOA, respectively. Our results at TOA are sensitive to the surface albedo in the SW and surface temperature in the LW. The absolute value of FE decrease (increase) in the SW (LW) with the surface albedo, resulting in an increasing LW/SW offset, up to 76%. The AHR profiles show a net warming within the dust layer, with a maximum value of 3.3 Kd-1. The ARF, FE and AHR are also highly sensitive to the dust optical properties in SW and LW. We evaluate this sensitivity by comparing the results obtained using two set of dust properties as input in our simulations: a) the prescribed dust model by Optical Properties of Aerosols and Clouds (OPAC) and; b) the dust optical properties derived from measurements of the size distribution and refractive index. Experimentally derived dust properties present larger SSA and asymmetry parameter in the SW than OPAC dust. Conversely, OPAC dust presents higher AOD in the LW range. These parameters drive the FE and AHR sensitivities in the SW and LW ranges, respectively. Therefore, when measured dust properties are used in our simulations: the ARF in the LW substantially reduces at surface and TOA (up to 57%); the absolute value of SW ARF is reduced by 15% at surface and an enhancement of 31% is observed at TOA; the AHR present less warming in the entire profile with deviations up to 53% within the dust layer, with respect to the results obtained using OPAC.

The embedded young stars in the Taurus-Auriga molecular cloud. I - Models for spectral energy distributions

NASA Technical Reports Server (NTRS)

Kenyon, Scott J.; Calvet, Nuria; Hartmann, Lee

1993-01-01

We describe radiative transfer calculations of infalling, dusty envelopes surrounding pre-main-sequence stars and use these models to derive physical properties for a sample of 21 heavily reddened young stars in the Taurus-Auriga molecular cloud. The density distributions needed to match the FIR peaks in the spectral energy distributions of these embedded sources suggest mass infall rates similar to those predicted for simple thermally supported clouds with temperatures about 10 K. Unless the dust opacities are badly in error, our models require substantial departures from spherical symmetry in the envelopes of all sources. These flattened envelopes may be produced by a combination of rotation and cavities excavated by bipolar flows. The rotating infall models of Terebey et al. (1984) models indicate a centrifugal radius of about 70 AU for many objects if rotation is the only important physical effect, and this radius is reasonably consistent with typical estimates for the sizes of circumstellar disks around T Tauri stars.

40 CFR Table 6 to Subpart Aaaaa of... - Periodic Monitoring for Compliance With Opacity and Visible Emissions Limits

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 14 2013-07-01 2013-07-01 false Periodic Monitoring for Compliance With Opacity and Visible Emissions Limits 6 Table 6 to Subpart AAAAA of Part 63 Protection of... Hazardous Air Pollutants for Lime Manufacturing Plants Pt. 63, Subpt. AAAAA, Table 6 Table 6 to Subpart...

40 CFR Table 6 to Subpart Aaaaa of... - Periodic Monitoring for Compliance With Opacity and Visible Emissions Limits

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 13 2010-07-01 2010-07-01 false Periodic Monitoring for Compliance With Opacity and Visible Emissions Limits 6 Table 6 to Subpart AAAAA of Part 63 Protection of... Hazardous Air Pollutants for Lime Manufacturing Plants Part 63, Subpt. AAAAA, Table 6 Table 6 to Subpart...

40 CFR Table 6 to Subpart Aaaaa of... - Periodic Monitoring for Compliance With Opacity and Visible Emissions Limits

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 14 2014-07-01 2014-07-01 false Periodic Monitoring for Compliance With Opacity and Visible Emissions Limits 6 Table 6 to Subpart AAAAA of Part 63 Protection of... Hazardous Air Pollutants for Lime Manufacturing Plants Pt. 63, Subpt. AAAAA, Table 6 Table 6 to Subpart...

40 CFR Table 6 to Subpart Aaaaa of... - Periodic Monitoring for Compliance With Opacity and Visible Emissions Limits

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 13 2011-07-01 2011-07-01 false Periodic Monitoring for Compliance With Opacity and Visible Emissions Limits 6 Table 6 to Subpart AAAAA of Part 63 Protection of... Hazardous Air Pollutants for Lime Manufacturing Plants Part 63, Subpt. AAAAA, Table 6 Table 6 to Subpart...

40 CFR Table 6 to Subpart Aaaaa of... - Periodic Monitoring for Compliance With Opacity and Visible Emissions Limits

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 14 2012-07-01 2011-07-01 true Periodic Monitoring for Compliance With Opacity and Visible Emissions Limits 6 Table 6 to Subpart AAAAA of Part 63 Protection of Environment... Pollutants for Lime Manufacturing Plants Part 63, Subpt. AAAAA, Table 6 Table 6 to Subpart AAAAA of Part 63...

Lightweight, high-opacity Bible paper by fiber loading

Treesearch

Klaus Doelle; Oliver Heise; John H. Klungness; Said M. AbuBakr

2000-01-01

This paper has been prepared in order to discuss Fiber Loading™ for lightweight, high-opacity bible paper. Incorporating fillers within pulp fibers has been subject to research since 1960 (Green et al. 1962, Scallan et al. 1985, Allen et al. 1992). Fiber Loading™ is a method for manufacturing precipitated calcium carbonate (PCC) directly within the pulp processing...

Extending fiber resources : fiber loading recycled fiber and mechanical pulps for lightweight, high opacity paper

Treesearch

Marguerite Sykes; John Klungness; Freya Tan; Mathew Stroika; Said Abubakr

1999-01-01

Production of a lightweight, high opacity printing paper is a common goal of papermakers using virgin or recycled fibers. Fiber loading is an innovative, commercially viable process that can substantially upgrade and extend most types of wood fibers. Fiber loading, a process carried out at high consistency and high alkalinity, precipitates calcium carbonate (PCC) in...

Online Public Access Catalog: The Google Maps of the Library World

ERIC Educational Resources Information Center

Bailey, Kieren

2011-01-01

What do Google Maps and a library's Online Public Access Catalog (OPAC) have in common? Google Maps provides users with all the information they need for a trip in one place; users can get directions and find out what attractions, hotels, and restaurants are close by. Librarians must find the ultimate OPAC that will provide, in one place, all the…

Web-Based Online Public Access Catalogues of IIT Libraries in India: An Evaluative Study

ERIC Educational Resources Information Center

Madhusudhan, Margam; Aggarwal, Shalini

2011-01-01

Purpose: The purpose of the paper is to examine the various features and components of web-based online public access catalogues (OPACs) of IIT libraries in India with the help of a specially designed evaluation checklist. Design/methodology/approach: The various features of the web-based OPACs in six IIT libraries (IIT Delhi, IIT Bombay, IIT…

We Never Have to Say Goodbye: Finding a Place for OPACS in Discovery Environments

ERIC Educational Resources Information Center

Matthews, J. Greg

2009-01-01

It is easy to lament the shortcomings of traditional online public access catalogs (OPACs) in the Google Age. Users cannot, for example, usually input a snippet of a long-forgotten pop song's chorus into an online library catalog and almost instantly retrieve a relevant result along with hundreds of other options. On the other hand, should OPACs…

Controlled-Release Personal Use Arthropod Repellent Formulation. Phase 2

DTIC Science & Technology

1986-09-15

damage, pitting M - Hypopyon N - Corneal neovascularization P - Pannus R - Unable to visualize due to severe opacity S - Granulation scar tissue POS...M - Hypopyon N - Corneal neovascularization P - Pannus R - Unable to visualize due to severe opacity S - Granulation scar tissue POS -Positive...Corneal epithelial damage, piling L - Corneal epithelial damage, pitting M - Hypopyon N - Corneal neovascularization P - Pannus R - Unable to

Lens opacities in women in Beaver Dam, Wisconsin: is there evidence of an effect of sex hormones?

PubMed Central

Klein, B E

1993-01-01

Analyses reported here suggest a protective effect of estrogen status on lens opacities, which are very common in adult Americans. Clinical trials are currently underway to assess protective effects of past menopausal estrogens on other disease. Evaluation of lenses of the participants would shed light on effects in the lens. PMID:8140704

40 CFR 62.15380 - How must I monitor opacity for air curtain incinerators that burn 100 percent yard waste?

Code of Federal Regulations, 2011 CFR

2011-07-01

... curtain incinerators that burn 100 percent yard waste? 62.15380 Section 62.15380 Protection of Environment... Combustion Units Constructed on or Before August 30, 1999 Air Curtain Incinerators That Burn 100 Percent Yard Waste § 62.15380 How must I monitor opacity for air curtain incinerators that burn 100 percent yard...

40 CFR 62.15380 - How must I monitor opacity for air curtain incinerators that burn 100 percent yard waste?

Code of Federal Regulations, 2014 CFR

2014-07-01

... curtain incinerators that burn 100 percent yard waste? 62.15380 Section 62.15380 Protection of Environment... Combustion Units Constructed on or Before August 30, 1999 Air Curtain Incinerators That Burn 100 Percent Yard Waste § 62.15380 How must I monitor opacity for air curtain incinerators that burn 100 percent yard...

40 CFR 60.1925 - How must I monitor opacity for air curtain incinerators that burn 100 percent yard waste?

Code of Federal Regulations, 2012 CFR

2012-07-01

... curtain incinerators that burn 100 percent yard waste? 60.1925 Section 60.1925 Protection of Environment... or Before August 30, 1999 Model Rule-Air Curtain Incinerators That Burn 100 Percent Yard Waste § 60.1925 How must I monitor opacity for air curtain incinerators that burn 100 percent yard waste? (a) Use...

40 CFR 60.1925 - How must I monitor opacity for air curtain incinerators that burn 100 percent yard waste?

Code of Federal Regulations, 2014 CFR

2014-07-01

... curtain incinerators that burn 100 percent yard waste? 60.1925 Section 60.1925 Protection of Environment... or Before August 30, 1999 Model Rule-Air Curtain Incinerators That Burn 100 Percent Yard Waste § 60.1925 How must I monitor opacity for air curtain incinerators that burn 100 percent yard waste? (a) Use...

40 CFR 62.15380 - How must I monitor opacity for air curtain incinerators that burn 100 percent yard waste?

Code of Federal Regulations, 2010 CFR

2010-07-01

... curtain incinerators that burn 100 percent yard waste? 62.15380 Section 62.15380 Protection of Environment... Combustion Units Constructed on or Before August 30, 1999 Air Curtain Incinerators That Burn 100 Percent Yard Waste § 62.15380 How must I monitor opacity for air curtain incinerators that burn 100 percent yard...

40 CFR 60.1925 - How must I monitor opacity for air curtain incinerators that burn 100 percent yard waste?

Code of Federal Regulations, 2010 CFR

2010-07-01

... curtain incinerators that burn 100 percent yard waste? 60.1925 Section 60.1925 Protection of Environment... or Before August 30, 1999 Model Rule-Air Curtain Incinerators That Burn 100 Percent Yard Waste § 60.1925 How must I monitor opacity for air curtain incinerators that burn 100 percent yard waste? (a) Use...

40 CFR 62.15380 - How must I monitor opacity for air curtain incinerators that burn 100 percent yard waste?

Code of Federal Regulations, 2012 CFR

2012-07-01

... curtain incinerators that burn 100 percent yard waste? 62.15380 Section 62.15380 Protection of Environment... Combustion Units Constructed on or Before August 30, 1999 Air Curtain Incinerators That Burn 100 Percent Yard Waste § 62.15380 How must I monitor opacity for air curtain incinerators that burn 100 percent yard...

40 CFR 62.15380 - How must I monitor opacity for air curtain incinerators that burn 100 percent yard waste?

Code of Federal Regulations, 2013 CFR

2013-07-01

... curtain incinerators that burn 100 percent yard waste? 62.15380 Section 62.15380 Protection of Environment... Combustion Units Constructed on or Before August 30, 1999 Air Curtain Incinerators That Burn 100 Percent Yard Waste § 62.15380 How must I monitor opacity for air curtain incinerators that burn 100 percent yard...

40 CFR 60.1925 - How must I monitor opacity for air curtain incinerators that burn 100 percent yard waste?

Code of Federal Regulations, 2013 CFR

2013-07-01

... curtain incinerators that burn 100 percent yard waste? 60.1925 Section 60.1925 Protection of Environment... or Before August 30, 1999 Model Rule-Air Curtain Incinerators That Burn 100 Percent Yard Waste § 60.1925 How must I monitor opacity for air curtain incinerators that burn 100 percent yard waste? (a) Use...

40 CFR 60.1925 - How must I monitor opacity for air curtain incinerators that burn 100 percent yard waste?

Code of Federal Regulations, 2011 CFR

2011-07-01

... curtain incinerators that burn 100 percent yard waste? 60.1925 Section 60.1925 Protection of Environment... or Before August 30, 1999 Model Rule-Air Curtain Incinerators That Burn 100 Percent Yard Waste § 60.1925 How must I monitor opacity for air curtain incinerators that burn 100 percent yard waste? (a) Use...

Knowing Where They Went: Six Years of Online Access Statistics via the Online Catalog for Federal Government Information

ERIC Educational Resources Information Center

Brown, Christopher C.

2011-01-01

As federal government information is increasingly migrating to online formats, libraries are providing links to this content via URLs or persistent URLs (PURLs) in their online public access catalogs (OPACs). Clickthrough statistics that accumulated as users visited links to online content in the University of Denver's library OPAC were gathered…

A Longitudinal Study of the Effects of OPAC Screen Changes on Searching Behavior and Searcher Success.

ERIC Educational Resources Information Center

Blecic, Deborah D.; Dorsch, Josephine L.; Koenig, Melissa H.; Bangalore, Nimala S.

1999-01-01

Describes a longitudinal study of four sets of OPAC (online public access catalog) transaction logs that examined the effects of screen changes in helping searchers improve their search behavior. Results show that while screen changes initially had a positive impact on search behavior, they were not always sustained over time. (Author/LRW)

The methane distribution on Titan: high resolution spectroscopy in the near-IR with Keck NIRSPEC/AO

NASA Astrophysics Data System (ADS)

Adamkovics, Mate; Mitchell, Jonathan L.

2014-11-01

The distribution of methane on Titan is a diagnostic of regional scale meteorology and large scale atmospheric circulation. The observed formation of clouds and the transport of heat through the atmosphere both depend on spatial and temporal variations in methane humidity. We have performed observations to measure the the distribution on methane Titan using high spectral resolution near-IR (H-band) observations made with NIRSPEC, with adaptive optics, at Keck Observatory in July 2014. This work builds on previous attempts at this measurement with improvement in the observing protocol and data reduction, together with increased integration times. Radiative transfer models using line-by-line calculation of methane opacities from the HITRAN2012 database are used to retrieve methane abundances. We will describe analysis of the reduced observations, which show latitudinal spatial variation in the region the spectrum that is thought to be sensitive to methane abundance. Quantifying the methane abundance variation requires models that include the spatial variation in surface albedo and meridional haze gradient; we will describe (currently preliminary) analysis of the the methane distribution and uncertainties in the retrieval.

Opacity meter for monitoring exhaust emissions from non-stationary sources

DOEpatents

Dec, John Edward

2000-01-01

Method and apparatus for determining the opacity of exhaust plumes from moving emissions sources. In operation, a light source is activated at a time prior to the arrival of a diesel locomotive at a measurement point, by means of a track trigger switch or the Automatic Equipment Identification system, such that the opacity measurement is synchronized with the passage of an exhaust plume past the measurement point. A beam of light from the light source passes through the exhaust plume of the locomotive and is detected by a suitable detector, preferably a high-rate photodiode. The light beam is well-collimated and is preferably monochromatic, permitting the use of a narrowband pass filter to discriminate against background light. In order to span a double railroad track and provide a beam which is substantially stronger than background, the light source, preferably a diode laser, must provide a locally intense beam. A high intensity light source is also desirable in order to increase accuracy at the high sampling rates required. Also included is a computer control system useful for data acquisition, manipulation, storage and transmission of opacity data and the identification of the associated diesel engine to a central data collection center.

Influence of artificial accelerated aging on the color stability and opacity of composites of different shades.

PubMed

Mundim, F M; Da Fonseca Roberti Garcia, L; Silva Sousa, A B; Cruvinel, D R; De Carvalho Panzeri Pires-De-Souza, F

2010-10-01

The aim of this study was to evaluate the influence of artificial accelerated aging on the color stability and opacity of composites of different shades. Four composites for direct use (Heliomolar, 4 Seasons, Tetric EvoCeram; QuiXfil) and one for indirect use (SR Adoro) in two shades were used: light (A2) and dark (C3 for direct, and D4 for indirect composite). QuiXfil was obtained in Universal shade. A Teflon matrix (12 X 2 mm) was used to obtain 54 specimens (N=6), which were submitted to color and opacity analysis (Spectrophotometer PCB 6807, Byk Gardner) before and after artificial accelerated aging for 384 hours. After the statistical analysis (2-way ANOVA - Bonferroni - P<0.05), significant color alteration was observed in the light and dark composites studied (P<0.05), with the exception of QuiXfil. Composite 4 Seasons/C3 showed less color alteration (ΔE=0.91). The opacity alteration (ΔOP) was higher for light composites. Artificial accelerated aging interfered in the optical properties assessed; however, the alterations seemed to be more related to the composites composition than to their shade.

Optical Properties of Polypropylene upon Recycling

PubMed Central

2013-01-01

In the last few years there has been an increasing interest in the possibility of recycling polymeric materials, using physical recycling. However, is it well known that polymers experience a depletion of all the properties upon recycling. These effects have been widely characterized in the literature for what concerns the mechanical or rheological properties. The changes of optical properties after recycling have been much less studied, even if, especially in food packaging, optical characteristics (above all the opacity) are of extreme importance, and thus it is quite significant to assess the effect of recycling on these properties. In this work, the influence of recycling steps on the opacity of films of a commercial grade of isotactic polypropylene (i-PP) was studied. The material was extruded several times to mimic the effect of recycling procedures. After extrusion, films were obtained by cooling samples of material at different cooling rates. The opacity of the obtained films was then measured and related to their crystallinity and morphology. It was found that opacity generally increases on increasing the amount of α phase and for the same amount of α phase on increasing the size of the spherulites. PMID:24288478

Particle transport in DIII-D plasmas

NASA Astrophysics Data System (ADS)

Kress, Peter; Mordijck, Saskia

2017-10-01

By analyzing the plasma opacity and density evolution during the ELM cycle in DIII-D H-mode plasmas in which the amount of gas fueling was altered, we find evidence for an inward particle pinch at the plasma edge which seems to become more pronounced at higher density. Furthermore, at the plasma edge we find a correlation between the pedestal density and opacity, which measures neutral penetration depth. The changes in edge opacity during an ELM cycle were calculated by using a detailed time history of measured plasma profiles. At the same time, the density evolution during an ELM cycle was investigated. We find that if the edge density increases through an increase in gas fueling, then opacity increases and neutral fueling penetration depth decreases. We also find that density at the top of the pedestal recovers faster following an ELM when the overall density level is higher, leading to a hollow profile inside of the pedestal top. All these results indicate that there must be an inward particle pinch in the pedestal which will be crucial in the fueling of future burning plasma devices. Supported by US DOE DE-SC0007880, DIII-D Grant Number DE-FC02-04ER54698.

Alignment effect of N2(A3Σu+) in the energy transfer reaction of aligned N2(A3Σu+) + NO(X2Π) → NO(A2Σ+) + N2(X1Σg+).

PubMed

Ohoyama, H; Maruyama, S

2012-06-28

Steric effect in the energy transfer reaction of N(2)(A(3)Σ(u)(+)) + NO(X(2)Π) → NO(A(2)Σ(+)) + N(2)(X(1)Σ(g)(+)) has been studied under crossed beam conditions at a collision energy of ~0.07 eV by using an aligned N(2)(A(3)Σ(u)(+)) beam prepared by a magnetic hexapole. The emission intensity of NO(A(2)Σ(+)) has been measured as a function of the magnetic orientation field direction (i.e., alignment of N(2)(A(3)Σ(u)(+))) in the collision frame. A significant alignment effect on the energy transfer probability is observed. The shape of the steric opacity function turns out to be most reactive at the oblique configuration of N(2)(A(3)Σ(u)(+)) with an orientation angle of γ(v(R)) ~ 45° with respect to the relative velocity vector (v(R)), which has a good correlation with the spatial distribution of the 2pπ(g)* molecular orbital of N(2)(A(3)Σ(u)(+)). We propose the electron exchange mechanism in which the energy transfer probability is dominantly controlled by the orbital overlap between N(2)(2pπ(g)*) and NO(6σ).

EGFR-mutant Non-small Cell Lung Cancer Accompanied by Transient Asymptomatic Pulmonary Opacities Successfully Treated with “Stop-And-Go” Osimertinib

PubMed Central

Kobayashi, Keigo; Naoki, Katsuhiko; Kuroda, Aoi; Yasuda, Hiroyuki; Kawada, Ichiro; Soejima, Kenzo; Betsuyaku, Tomoko

2017-01-01

A 69-year-old man with post-operative recurrence of lung adenocarcinoma was treated with multiple chemotherapies, including epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors. A second biopsy revealed an EGFR T790M mutation. As 10th-line chemotherapy, osimertinib was initiated. After 24 weeks, chest computed tomography (CT) revealed asymptomatic ground-glass opacities in both lobes. After four weeks of osimertinib discontinuation, imaging revealed rapid lung cancer progression. Osimertinib was resumed. After 11 weeks, CT revealed decreased lung nodules with no exacerbation of interstitial lung disease. We describe a patient who experienced transient asymptomatic pulmonary opacities during treatment with osimertinib, which was successfully managed by a “stop-and-go” approach. PMID:29269665

Design of Initial Opacity Platform at the National Ignition Facility

NASA Astrophysics Data System (ADS)

Heeter, R. F.; Ahmed, M. F.; Ayers, S. L.; Emig, J. A.; Iglesias, C. A.; Liedahl, D. A.; Schneider, M. B.; Wilson, B. G.; Huffman, E. J.; King, J. A.; Opachich, Y. P.; Ross, P. W.; Bailey, J. E.; Rochau, G. A.; Craxton, R. S.; Garcia, E. M.; McKenty, P. W.; Zhang, R.; Cardenas, T.; Devolder, B. G.; Dodd, E. S.; Kline, J. L.; Sherrill, M. E.; Perry, T. S.

2016-10-01

The absorption and re-emission of x-rays by partly stripped ions plays a critical role in stars and in many laboratory plasmas. A NIF Opacity Platform has been designed to resolve a persistent disagreement between theory and experiments on the Sandia Z facility, studying iron in conditions closely related to the solar radiation-convection transition boundary. A laser heated hohlraum ``oven'' will produce iron plasmas at temperatures >150 eV and electron densities >=7x1021/cm3, and be probed with continuum X-rays from a capsule implosion backlighter source. The resulting X-ray transmission spectra will be recorded on a specially designed Opacity Spectrometer. This work was performed under the auspices of the U.S. Department of Energy by LLNL under Contract DE-AC52-07NA27344.

Study of X-ray photoionized Fe plasma and comparisons with astrophysical modeling codes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Foord, M E; Heeter, R F; Chung, H

The charge state distributions of Fe, Na and F are determined in a photoionized laboratory plasma using high resolution x-ray spectroscopy. Independent measurements of the density and radiation flux indicate the ionization parameter {zeta} in the plasma reaches values {zeta} = 20-25 erg cm s{sup -1} under near steady-state conditions. A curve-of-growth analysis, which includes the effects of velocity gradients in a one-dimensional expanding plasma, fits the observed line opacities. Absorption lines are tabulated in the wavelength region 8-17 {angstrom}. Initial comparisons with a number of astrophysical x-ray photoionization models show reasonable agreement.

Cataloguing E-Books in UK Higher Education Libraries: Report of a Survey

ERIC Educational Resources Information Center

Belanger, Jacqueline

2007-01-01

Purpose: The purpose of this paper is to discuss the results of a 2006 survey of UK Higher Education OPACs in order to provide a snapshot of cataloguing practices for e-books. Design/methodology/approach: The OPACs of 30 UK HE libraries were examined in July/August 2006 to determine which e-books were catalogued, and the level of cataloguing…

Control of Hemotropic Diseases of Dogs.

DTIC Science & Technology

1977-12-31

isolant. Inoculated dogs develo- ped signs of the disease which included fever , weight loss, lym- phodenopathy, corneal opacity, and pancytopenia. Of...in Alsatian dogs infected with E. canis, was not seen in thesedogs; however, 2 dogs devel- oped cutaneous petechial and ecchymotic hemorrhages at...included fever , weight loss, lymphadenopathy, - -- 19 corneal opacity, and pancytopenia. Of 3 dogs that died during the course of the study, one died with

The Effects of Webopac Self Training Tool with Guided Exploration on Information Literacy Skills among First Year Degree Students

ERIC Educational Resources Information Center

Ismail, Mohd Nasir; Mamat, Nurfaezah; Jamaludin, Adnan

2018-01-01

The purpose of this study is to investigate effects of WebOPAC Self Training Tool with Guided Exploration (WSTTG), WebOPAC Self Training Tool with non-guided exploration (WSTT) and Traditional (T) groups as the learning strategies on information literacy (IL) skills standards among first year degree students in Malaysian public university. The…

How Next-Gen R U? A Review of Academic OPACs in the United States and Canada

ERIC Educational Resources Information Center

Hofmann, Melissa A.; Yang, Sharon Q.

2011-01-01

As a concept, the next-generation catalog (NGC) is not new to librarians, who have been wishing for better OPAC interfaces for their integrated library systems (ILSs). The NGC has been the focus of discussion for more than 5 years now, from the 2006 report of the implementation of Endeca at North Carolina State University, to Marshall Breeding's…

40 CFR 60.1450 - How must I monitor opacity for air curtain incinerators that burn 100 percent yard waste?

Code of Federal Regulations, 2012 CFR

2012-07-01

... curtain incinerators that burn 100 percent yard waste? 60.1450 Section 60.1450 Protection of Environment... Air Curtain Incinerators That Burn 100 Percent Yard Waste § 60.1450 How must I monitor opacity for air curtain incinerators that burn 100 percent yard waste? (a) Use EPA Reference Method 9 in appendix A of...

40 CFR 62.14820 - How must I monitor opacity for air curtain incinerators that burn 100 percent wood wastes, clean...

Code of Federal Regulations, 2013 CFR

2013-07-01

... curtain incinerators that burn 100 percent wood wastes, clean lumber, and/or yard waste? 62.14820 Section... Before November 30, 1999 Air Curtain Incinerators That Burn 100 Percent Wood Wastes, Clean Lumber And/or Yard Waste § 62.14820 How must I monitor opacity for air curtain incinerators that burn 100 percent...

40 CFR 60.1450 - How must I monitor opacity for air curtain incinerators that burn 100 percent yard waste?

Code of Federal Regulations, 2010 CFR

2010-07-01

... curtain incinerators that burn 100 percent yard waste? 60.1450 Section 60.1450 Protection of Environment... Air Curtain Incinerators That Burn 100 Percent Yard Waste § 60.1450 How must I monitor opacity for air curtain incinerators that burn 100 percent yard waste? (a) Use EPA Reference Method 9 in appendix A of...

40 CFR 60.1450 - How must I monitor opacity for air curtain incinerators that burn 100 percent yard waste?

Code of Federal Regulations, 2011 CFR

2011-07-01

... curtain incinerators that burn 100 percent yard waste? 60.1450 Section 60.1450 Protection of Environment... Air Curtain Incinerators That Burn 100 Percent Yard Waste § 60.1450 How must I monitor opacity for air curtain incinerators that burn 100 percent yard waste? (a) Use EPA Reference Method 9 in appendix A of...

40 CFR 60.2972 - How must I monitor opacity for air curtain incinerators that burn only wood waste, clean lumber...

Code of Federal Regulations, 2013 CFR

2013-07-01

... curtain incinerators that burn only wood waste, clean lumber, and yard waste? 60.2972 Section 60.2972... Commenced on or After June 16, 2006 Air Curtain Incinerators That Burn Only Wood Waste, Clean Lumber, and Yard Waste § 60.2972 How must I monitor opacity for air curtain incinerators that burn only wood waste...

40 CFR 60.2972 - How must I monitor opacity for air curtain incinerators that burn only wood waste, clean lumber...

Code of Federal Regulations, 2014 CFR

2014-07-01

... curtain incinerators that burn only wood waste, clean lumber, and yard waste? 60.2972 Section 60.2972... Commenced on or After June 16, 2006 Air Curtain Incinerators That Burn Only Wood Waste, Clean Lumber, and Yard Waste § 60.2972 How must I monitor opacity for air curtain incinerators that burn only wood waste...

40 CFR 62.14820 - How must I monitor opacity for air curtain incinerators that burn 100 percent wood wastes, clean...

Code of Federal Regulations, 2012 CFR

2012-07-01

... curtain incinerators that burn 100 percent wood wastes, clean lumber, and/or yard waste? 62.14820 Section... Before November 30, 1999 Air Curtain Incinerators That Burn 100 Percent Wood Wastes, Clean Lumber And/or Yard Waste § 62.14820 How must I monitor opacity for air curtain incinerators that burn 100 percent...

40 CFR 60.3067 - How must I monitor opacity for air curtain incinerators that burn only wood waste, clean lumber...

Code of Federal Regulations, 2014 CFR

2014-07-01

... curtain incinerators that burn only wood waste, clean lumber, and yard waste? 60.3067 Section 60.3067... Incinerators That Burn Only Wood Waste, Clean Lumber, and Yard Waste § 60.3067 How must I monitor opacity for air curtain incinerators that burn only wood waste, clean lumber, and yard waste? (a) Use Method 9 of...

40 CFR 60.3067 - How must I monitor opacity for air curtain incinerators that burn only wood waste, clean lumber...

Code of Federal Regulations, 2012 CFR

2012-07-01

... curtain incinerators that burn only wood waste, clean lumber, and yard waste? 60.3067 Section 60.3067... Incinerators That Burn Only Wood Waste, Clean Lumber, and Yard Waste § 60.3067 How must I monitor opacity for air curtain incinerators that burn only wood waste, clean lumber, and yard waste? (a) Use Method 9 of...

40 CFR 60.3067 - How must I monitor opacity for air curtain incinerators that burn only wood waste, clean lumber...

Code of Federal Regulations, 2013 CFR

2013-07-01

... curtain incinerators that burn only wood waste, clean lumber, and yard waste? 60.3067 Section 60.3067... Incinerators That Burn Only Wood Waste, Clean Lumber, and Yard Waste § 60.3067 How must I monitor opacity for air curtain incinerators that burn only wood waste, clean lumber, and yard waste? (a) Use Method 9 of...

40 CFR 60.1450 - How must I monitor opacity for air curtain incinerators that burn 100 percent yard waste?

Code of Federal Regulations, 2014 CFR

2014-07-01

... curtain incinerators that burn 100 percent yard waste? 60.1450 Section 60.1450 Protection of Environment... Air Curtain Incinerators That Burn 100 Percent Yard Waste § 60.1450 How must I monitor opacity for air curtain incinerators that burn 100 percent yard waste? (a) Use EPA Reference Method 9 in appendix A of...

40 CFR 62.14820 - How must I monitor opacity for air curtain incinerators that burn 100 percent wood wastes, clean...

Code of Federal Regulations, 2014 CFR

2014-07-01

... curtain incinerators that burn 100 percent wood wastes, clean lumber, and/or yard waste? 62.14820 Section... Before November 30, 1999 Air Curtain Incinerators That Burn 100 Percent Wood Wastes, Clean Lumber And/or Yard Waste § 62.14820 How must I monitor opacity for air curtain incinerators that burn 100 percent...